Freescale MC34937 Three phase field effect transistor pre-driver Datasheet

Freescale Semiconductor
Technical Data
Document Number: MC34937
Rev. 2.0, 9/2013
Three Phase Field Effect
Transistor Pre-driver
34937A
Industrial
The 34937A is a field effect transistor (FET) pre-drivers designed
for three phase motor control and similar applications. The integrated
circuit (IC) uses SMARTMOS technology.
The IC contains three high side FET pre-drivers and three low side
FET pre-drivers. Three external bootstrap capacitors provide gate
charge to the high side FETs.
The IC interfaces to a MCU via six direct input control signals, an
SPI port for device setup and asynchronous reset, enable and
interrupt signals. Both 5.0 and 3.0 V logic level inputs are accepted
and 5.0 V logic level outputs are provided.
THREE PHASE PRE-DRIVER
Features
• Extended supply voltage operating range: 6.0 to 58 V
• Wide dead time range (50 ns to 12 s) programmable via the SPI
port
• External FET gate drive capability of >1.0 A with protection
• Charge pump ensures sufficient external FET drive at low supply
voltages
• Device protection against reverse charge-injection from CGD and
CGS of external FETS
• Integrated overcurrent, desaturation, and phase fault-detection
• Immunity against positive or negative transient voltage spikes on
the gate driver
• Current shoot-through protection built into dead time control
• Supports direct 3.3 V and 5.0 V logic interface to MCUs
• Integrated current sensing amplifier
• Device configuration and diagnostics through the SPI
VSYS
EK SUFFIX (Pb-FREE)
98ASA99334D
54-PIN SOICW-EP
Applications
• 12 V - 48 V 3-phase brushless DC (BLDC) motors
and permanent magnet synchronous motors (PMSM)
• E-Bike, hospital beds, electric chair/scooter
• CPAPs, inflation pumps, industrial fans
• Portable power tools, commercial fans/blowers
• Small kitchen appliances
34937
VPUMP
VSUP
PUMP
VPWR
VLS
PA_HS_G
PB_HS_G
PC_HS_G
VDD
PA_HS_S
PB_HS_S
PC_HS_S
VSS
3
3
3
MCU
OR
DSP
PX_HS
PX_LS
PHASEX
CS
SI
SCLK
SO
RST
INT
EN1
GND
EN2
PA_LS_G
PB_LS_G
PC_LS_G
PX_LS_S
AMP_P
AMP_N
AMP_OUT
RSEN
Figure 1. 34937A Simplified Application Diagram
Freescale Semiconductor, Inc. reserves the right to change the detail specifications,
as may be required, to permit improvements in the design of its products.
© Freescale Semiconductor, Inc., 2013. All rights reserved.
ORDERABLE PARTS
ORDERABLE PARTS
Table 1. Orderable Part Variations
Part Number (1)
Notes
MC34937APEK
Temperature (TA)
Package
-40 to 125 °C
54 SOICW-EP
Notes
1. To Order parts in Tape & Reel, add the R2 suffix to the part number.
34937A
2
Analog Integrated Circuit Device Data
Freescale Semiconductor
INTERNAL BLOCK DIAGRAM
INTERNAL BLOCK DIAGRAM
PUMP
VPUMP
VPWR
VSUP
MAIN
CHARGE
PUMP
PGND
TRICKLE
CHARGE
PUMP
HOLD
-OFF
CIRCUIT
VLS
REG.
5.0 V
REG.
VDD
OSCILLATOR
VLS
VDD
UV
DETECT
3X
RST
PX_BOOT
T-LIM
INT
VSUP
EN1
EN2
3
PX_HS
CONTROL
LOGIC
3
PX_LS
+
DESAT. 1.4 V
COMP
+
-
HIGH
SIDE
DRIVER
PX_HS_S
CS
SI
+
-
SCLK
PHASE
VSUP
COMP.
SO
3
PHASEX
OC_OUT
GND(2)
PX_HS_G
+
-
LOW
SIDE
DRIVER
PX_LS_G
+
-
OVERCUR.
COMP.
PX_LS_S
I-SENSE
AMP.
VSS OC_TH AMP_OUT
AMP_N
AMP_P
VLS_CAP
Figure 2. 34937A Simplified Internal Block Diagram
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
3
PIN CONNECTIONS
PIN CONNECTIONS
PHASEA
PGND
EN1
EN2
RST
N/C
PUMP
VPUMP
VSUP
PHASEB
PHASEC
PA_HS
PA_LS
VDD
PB_HS
PB_LS
INT
CS
SI
SCLK
SO
PC_LS
PC_HS
AMP_OUT
AMP_N
AMP_P
OC_OUT
Transparent
Top View
1
54
2
53
3
52
4
51
5
50
6
49
7
48
8
47
9
46
10
45
11
44
12
43
13
42
14
41
15
40
16
39
17
38
18
37
19
36
20
.35
21
34
22
33
23
32
24
31
25
30
26
29
27
28
VPWR
N/C
N/C
VLS
N/C
N/C
PA_BOOT
PA_HS_G
PA_HS_S
PA_LS_G
PA_LS_S
PB_BOOT
PB_HS_G
PB_HS_S
PB_LS_G
PB_LS_S
PC_BOOT
PC_HS_G
PC_HS_S
PC_LS_G
PC_LS_S
N/C
VLS_CAP
GND1
GND0
VSS
OC_TH
Figure 3. 34937A Pin Connections
A functional description of each pin can be found in the Functional Pin Description section beginning on page 21.
Table 2. 34937A Pin Definitions
Pin
Pin Name
Pin Function
Formal Name
Definition
1
PHASEA
Digital Output
Phase A
Totem Pole output of Phase A comparator. This output is low when the
voltage on PA_HS_S (Source of High Side FET) is less than 50% of VSUP
2
PGND
Ground
Power Ground
3
EN1
Digital Input
Enable 1
Logic signal input must be high (ANDed with EN2) to enable any gate drive
output.
4
EN2
Digital Input
Enable 2
Logic signal input must be high (ANDed with EN1) to enable any gate drive
output
5
RST
Digital Input
Reset
6, 33, 49,
50, 52, 53
N/C
–
No Connect
7
PUMP
Power Drive
Out
Pump
Charge pump output
8
VPUMP
Power Input
Voltage Pump
Charge pump supply
9
VSUP
Analog Input
Supply Voltage
Supply voltage to the load. This pin is to be connected to the common
Drains of the external High Side FETs
10
PHASEB
Digital Output
Phase B
Power ground for charge pump
Reset input
Do not connect these pins
Totem Pole output of Phase B comparator. This output is low when the
voltage on PB_HS_S (Source of High Side FET) is less than 50% of VSUP
34937A
4
Analog Integrated Circuit Device Data
Freescale Semiconductor
PIN CONNECTIONS
Table 2. 34937A Pin Definitions (continued)
Pin
Pin Name
Pin Function
Formal Name
Definition
11
PHASEC
Digital Output
Phase C
Totem Pole output of Phase C comparator. This output is low when the
voltage on PC_HS_S (Source of High Side FET) is less than 50% of VSUP
12
PA_HS
Digital Input
Phase A High Side
Active low input logic signal enables the High Side Driver for Phase A
13
PA_LS
Digital Input
Phase A Low Side
Active high input logic signal enables the Low Side Driver for Phase A
14
VDD
Analog Output
VDD Regulator
15
PB_HS
Digital Input
Phase B High Side
Active low input logic signal enables the High Side Driver for Phase B
16
PB_LS
Digital Input
Phase B Low Side
Active high input logic signal enables the Low Side Driver for Phase B
17
INT
Digital Output
Interrupt
18
CS
Digital Input
Chip Select
19
SI
Digital Input
Serial In
20
SCLK
Digital Input
Serial Clock
21
SO
Digital Output
Serial Out
22
PC_LS
Digital Input
Phase C Low Side
Active high input logic signal enables the Low Side Driver for Phase C
23
PC_HS
Digital Input
Phase C High Side
Active low input logic signal enables the High Side Driver for Phase C
24
AMP_OUT
Analog Output
Amplifier Output
Output of the current-sensing amplifier
25
AMP_N
Analog Input
Amplifier Invert
Inverting input of the current-sensing amplifier
26
AMP_P
Analog Input
Amplifier Non-Invert
27
OC_OUT
Digital Output
Overcurrent Out
28
OC_TH
29
VSS
Ground
30, 31
GND
Ground
32
VLS_CAP
34
PC_LS_S
35
PC_LS_G
36
PC_HS_S
Power Input
Phase C High Side
Source
Source connection for Phase C High Side FET
37
PC_HS_G
Power Output
Phase C High Side
Gate Drive
Gate Drive for output Phase C High Side FET
38
PC_BOOT
Analog Input
Phase C Bootstrap
Bootstrap capacitor for Phase C
39
PB_LS_S
Power Input
Phase B Low Side
Source
Source connection for Phase B Low Side FET
40
PB_LS_G
41
PB_HS_S
Power Input
Phase B High Side
Source
Source connection for Phase B High Side FET
42
PB_HS_G
Power Output
Phase B High Side
Gate Drive
Gate Drive for output Phase B High Side
43
PB_BOOT
Analog Input
Phase B Bootstrap
Bootstrap capacitor for Phase B
VDD regulator output capacitor connection.
Interrupt pin output
Chip Select input. It frames SPI commands and enables SPI port
Input data for SPI port. Clocked on the falling edge of SCLK, MSB first
Clock for SPI port and typically is 3.0 MHz
Output data for SPI port. Tri-state until CS becomes low
Non-inverting input of the current-sensing amplifier
Totem pole digital output of the Overcurrent Comparator
Analog Input Overcurrent Threshold Threshold of the overcurrent detector
Voltage Source Supply Ground reference for logic interface and power supplies
Ground
Analog Output VLS Regulator Output
Capacitor
Power Input
Phase C Low Side
Source
Substrate and ESD reference, connect to VSS
VLS Regulator connection for additional output capacitor, providing lowimpedance supply source for Low Side Gate Drive
Source connection for Phase C Low Side FET
Power Output Phase C Low Side Gate Gate drive output for Phase C Low Side
Drive
Power Output Phase B Low Side Gate Gate Drive for output Phase B Low Side
Drive
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
5
PIN CONNECTIONS
Table 2. 34937A Pin Definitions (continued)
Pin
Pin Name
Pin Function
Formal Name
Definition
44
PA_LS_S
Power Input
Phase A Low Side
Source
45
PA_LS_G
46
PA_HS_S
Power Input
Phase A High Side
Source
Source connection for Phase A High Side FET
47
PA_HS_G
Power Output
Phase A High Side
Gate Drive
Gate Drive for output Phase A High Side
48
PA_BOOT
Analog Input
Phase A Bootstrap
Bootstrap capacitor for Phase A
51
VLS
Analog Output
VLS Regulator
VLS regulator output. Power supply for the gate drives
54
VPWR
Power Input
Voltage Power
Power supply input for gate drives
EP
Ground
Exposed Pad
Device will perform as specified with the exposed pad un-terminated
(floating) however, it is recommended that the exposed pad be terminated
to pin 29 (VSS) and system ground
Source connection for Phase A Low Side FET
Power Output Phase A Low Side Gate Gate Drive for output Phase A Low Side
Drive
34937A
6
Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
Table 3. Maximum Ratings
All voltages are with respect to VSS unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent
damage to the device.
Ratings
Symbol
Value
Unit
ELECTRICAL RATINGS
VSUP Supply Voltage
V
VSUP
Normal Operation (Steady-state)
58
Transient Survival(2)
-1.5 to 80
VPWR Supply Voltage
VPWR
Normal Operation (Steady-state)
V
58
Transient Survival(2)
-1.5 to 80
Charge Pump (PUMP, VPUMP)
VPUMP
-0.3 to 40
V
VLS Regulator Outputs (VLS, VLS_CAP)
VLS
-0.3 to 18
V
Logic Supply Voltage
VDD
-0.3 to 7.0
V
Logic Output (INT, SO, PHASEA, PHASEB, PHASEC, OC_OUT)(3)
VOUT
-0.3 to 7.0
V
VIN
-0.3 to 7.0
V
Logic Input Pin Voltage (EN1, EN2, Px_HS, Px_LS, SI, SCLK, CS, RST) 10 mA
Amplifier Input Voltage
V
VIN_A
(Both Inputs-GND), (AMP_P - GND) or (AMP_N - GND) 6.0 mA source or sink
Overcurrent comparator threshold 10 mA
-7.0 to 7.0
VOC
-0.3 to 7.0
High Side bootstrap (PA_BOOT, PB_BOOT, PC_BOOT)
VBOOT
75
High Side (PA_HS_G, PB_HS_G, PC_HS_G)
VHS_G
75
Low Side (PA_LS_G, PB_LS_G, PC_LS_G)
VLS_G
16
Driver Output Voltage
(4)
Driver Voltage Transient Survival
V
(5)
High Side (PA_HS_G, PB_HS_G, PC_HS_G, PA_HS_S, PB_HS_S,
PC_HS_S)
Low Side (PA_LS_G, PB_LS_G, PC_LS_G, PA_LS_S, PB_LS_S, PC_LS_S)
Notes
2.
3.
4.
5.
V
V
VHS_G
-7.0 to 75.0
VHS_S
-7.0 to 75.0
VLS_G
-7.0 to 18.0
VLS_S
-7.0 to 7.0
The device will withstand a voltage transient as defined by ISO7637 with peak voltage of 80 V.
Short-circuit proof, the device will not be damaged or induce unexpected behavior due to shorts to external sources within this range.
This voltage should not be applied without also taking voltage at HS_S and voltage at PX_LS_S into account.
Actual operational limitations may differ from survivability limits. The VLS - VLS_S differential and the VBOOT - VHS_S differential must be
greater than 3.0 V to insure the output gate drive will maintain a commanded OFF condition on the output.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
7
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS
Table 3. Maximum Ratings (continued)
All voltages are with respect to VSS unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent
damage to the device.
Ratings
ESD Voltage(6)
Symbol
Value
VESD
Human Body Model - HBM (All pins except for the pins listed below)
Pins: PA_Boot, PA_HS_S, PA_HS_G, PB_Boot, PB_HS_S, PB_HS_G,
PC_Boot, PC_HS_S, PC_HS_G, VPWR
Unit
V
±2000
±1000
Charge Device Model - CDM
Corner pins
±750
All other pins
±300
THERMAL RATINGS
Storage Temperature
Operating Junction Temperature
Thermal Resistance
(7)
TSTG
-55 to +150
°C
TJ
-40 to +150
°C
(8)
Junction-to-Case
Soldering Temperature(9)
°C/W
RJC
3.0
TSOLDER
Note 10
°C
Notes
6. ESD testing is performed in accordance with the Human Body Model (HBM) (CZAP = 100 pF, RZAP = 1500 W) and the Charge Device
Model (CDM), Robotic (CZAP = 4.0 pF).
7.
8.
9.
10.
In order to meet or exceed the expected reliability performance level over 10 years of continuous operation, the user must take measures
to guarantee that the device’s average junction temperature does not exceed 125ºC. The device’s maximum junction temperature
remains as specified in the data sheet.
Case is considered EP - pin 55 under the body of the device. The actual power dissipation of the device is dependent on the operating
mode, the heat transfer characteristics of the board and layout and the operating voltage. See Figure 24 and Figure 25 for examples of
power dissipation profiles of two common configurations. Operation above the maximum operating junction temperature will result in a
reduction in reliability leading to malfunction or permanent damage to the device.
Pin soldering temperature limit is for 10 seconds maximum duration. Not designed for immersion soldering. Exceeding these limits may
cause malfunction or permanent damage to the device.
Freescale’s Package Reflow capability meets Pb-free requirements for JEDEC standard J-STD-020C. For Peak Package Reflow
Temperature and Moisture Sensitivity Levels (MSL), Go to www.freescale.com, search by part number [e.g. remove prefixes/suffixes
and enter the core ID to view all orderable parts. (i.e. MC33xxxD enter 33xxx), and review parametrics.
34937A
8
Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
Table 4. Static Electrical Characteristics
Characteristics noted under conditions 8.0 V  VPWR = VSUP  40 V-40 C  TA  125 C, unless otherwise noted. Typical
values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
VPWR Supply Voltage Startup Threshold(11)
VPWR_ST
–
6.0
8.0
VSUP Supply Current, VPWR = VSUP = 40 V
ISUP
Unit
POWER INPUTS
V
mA
RST and ENABLE = 5.0 V
No output loads on Gate Drive Pins, No PWM
–
1.0
–
No output loads on Gate Drive Pins, 20 kHz, 50% Duty Cycle
–
–
10
VPWR Supply Current, VPWR = VSUP = 40 V
IPWR_ON
mA
RST and ENABLE = 5.0 V
No output loads on Gate Drive Pins, No PWM, Outputs initialized
–
11
20
Output Loads = 620 nC per FET, 20 kHz PWM(12)
–
–
95
Sleep State Supply Current, RST = 0 V
µA
VSUP = 40 V
ISUP
–
14
30
VPWR = 40 V
IPWR
–
56
100
–
–
1.3
22
28
32
–
–
1.2
Sleep State Output Gate Voltage
VGATESS
IG < 100 µA
Trickle Charge Pump (Bootstrap Voltage)(16)
V
VBoot
VSUP = 14 V
Bootstrap Diode Forward Voltage at 10 mA
VF
V
V
VDD INTERNAL REGULATOR
VDD Output Voltage, VPWR = 8 to 40 V, C = 0.47 µF(13)
VDD
External Load IDD_EXT = 0 to 1.0 mA
Internal VDD Supply Current, VDD = 5.5 V, No External Load
V
4.5
–
5.5
IDD
–
–
12
mA
IPEAK
350
600
800
mA
VLS
13.5
15
17
V
VTHVLS
7.5
8.0
8.5
V
VLS REGULATOR
Peak Output Current, VPWR = 16 V, VLS = 10 V
Linear Regulator Output Voltage, IVLS = 0 to 60 mA,VPWR > VLS + 2.0
VLS Disable Threshold(15)
V(14)
Notes
11. Operation with the Charge Pump is recommended when minimum system voltage could be less than 14 V. VPWR must exceed this
threshold in order for the Charge Pump and VDD regulator to startup and drive VPWR to > 8.0 V. Once VPWR exceeds 8.0 V, the circuits
will continue to operate even if system voltage drops below 6.0 V.
12. This parameter is guaranteed by design. It is not production tested.
13. Minimum external capacitor for stable VDD operation is 0.47 µF.
14.
Recommended external capacitor for the VLS regulator is 2.2 µF low ESR at each pin VLS and VLS_CAP.
15.
When VLS is less than this value, the outputs are disabled and HOLDOFF circuits are active. Recovery requires initialization when VLS
rises above this threshold again. A filter delay of approximately 700 ns on the comparator output eliminates responses to spurious
transients on VLS.
16.
See Figure 11 for typical capability to maintain gate voltage with a 5.0 µA load.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
9
ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
Table 4. Static Electrical Characteristics (continued)
Characteristics noted under conditions 8.0 V  VPWR = VSUP  40 V-40 C  TA  125 C, unless otherwise noted. Typical
values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
Unit
High Side Switch On Resistance
RDS(on)_HS
–
Low Side Switch On Resistance
RDS(on)_LS
–
6.0
10

5.0
9.4
VTHREG

250
500
900
mV
IOUT = 40 mA, 6.0 V < VSYS < 8.0 V
8.5
9.5
–
IOUT = 40 mA, VSYS > = 8.0 V
12
–
–
VPWR = VSUP = 16 V, -40 C  TA  25 C
–
–
6.0
VPWR = VSUP = 16 V, 25 C TA  125 C
–
–
8.5
–
–
3.0
–
–
0.5
VPWR = VSUP = 16 V, -40 C  TA  25 C
–
–
6.0
VPWR = VSUP = 16 V, 25 C TA  125 C
–
–
8.5
–
–
3.0
–
–
0.5
CHARGE PUMP
Charge Pump
Regulation Threshold Difference(17), (19)
Charge Pump Output Voltage(18), (19)
VCP
V
GATE DRIVE
High Side Driver On Resistance (Sourcing)
High Side Driver On Resistance (Sinking)
Low Side Driver On Resistance (Sourcing)
Low Side Driver On-Resistance (Sinking)
IHS_INJ

RDS(ON)_L_SINK
ILS_INJ
Gate Source Voltage, VPWR = VSUP = 40 V
High Side, IGATE =
0(21)
Low Side, IGATE = 0
Reverse High Side Gate Holding
Voltage(22)
A

RDS(ON)_L_SRC
VPWR = VSUP = 16 V
Low Side Current Injection Allowed Without Malfunction(19), (20)

RDS(ON)_H_SINK
VPWR = VSUP = 16 V
High Side Current Injection Allowed Without Malfunction(19), (20)

RDS(ON)_H_SRC

V
VGS_H
13
14.8
16.5
VGS_L
13
15.4
17
VHS_G_HOLD
V
Gate Output Holding Current = 2.0 µA
–
10
15
Gate Output Holding Current = 5.0 µA, VSUP<26 V
–
10
15
Gate Output Holding Current = 5.0 µA, VSUP<40 V
–
–
15
Notes
17. When VLS is this amount below the normal VLS linear regulation threshold, the charge pump is enabled.
18. VSYS is the system voltage on the input to the charge pump. Recommended external components: 1.0 µF MLC, MUR 120 diode.
19.
20.
21.
22.
This parameter is a design characteristic, not production tested.
Current injection only occurs during output switch transitions. The IC is immune to specified injected currents for a duration of
approximately 1.0 µs after an output switch transition. 1.0 µs is sufficient for all intended applications of this IC.
If a slightly higher gate voltage is required, larger bootstrap capacitors are required. At high duty cycles, the bootstrap voltage may not
recover completely, leading to a higher output on-resistance. This effect can be minimized by using low ESR capacitors for the bootstrap
and the VLS capacitors.
High Side Gate Holding voltage is the voltage between the Gate and Source of the high side FET when held in an on condition. The
trickle charge pump supplies bias and holding current for the High Side FET gate driver and output to maintain voltages after bootstrap
events. See Figure 11 for typical 100% high side gate voltage with a 5.0 µA load. This parameter is a design characteristic, not
production tested.
34937A
10
Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
Table 4. Static Electrical Characteristics (continued)
Characteristics noted under conditions 8.0 V  VPWR = VSUP  40 V-40 C  TA  125 C, unless otherwise noted. Typical
values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
Unit
OVERCURRENT COMPARATOR
Common Mode Input Range(24)
VCM
2.0
–
VDD-0.02
V
VOS_OC
-50
–
50
mV
VOC_HYST
50
300
mV
High Level at IOH = -500 µA
VOH
0.85 VDD
–
VDD
Low Level at IOL = 500 µA
VOL
–
–
0.5
IHOLD
10
–
300
µA
High Level Input Voltage Threshold
VIH_TH
0.5 VSUP
–
0.65 VSUP
V
Low Level Input Voltage Threshold
VIL_TH
0.3 VSUP
–
0.45 VSUP
V
High Level Output Voltage at IOH = -500 µA
VOH
0.85 VDD
–
VDD
V
Low Level Output Voltage at IOL = 500 µA
VOL
–
–
0.5
V
High Side Source Input Resistance(23), (28)
RIN
–
40
–
k
VDES_TH
1.2
1.4
1.6
V
Recommended External Series Resistor (See Figure 9)
RS
–
1.0
–
k
Recommended External Feedback Resistor (See Figure 9)(29)
RFB
5.0
–
15
Input Offset Voltage
Overcurrent Comparator Threshold Hysteresis(23)
Output Voltage
V
HOLD OFF CIRCUIT
Hold Off Current (At Each GATE Pin)
3.0 V < VSUP < 40 V, VGATE = 1.0 V(25)
PHASE COMPARATOR
DESATURATION DETECTOR
Desaturation Detector Threshold(26)
CURRENT SENSE AMPLIFIER
Limited by the Output Voltage Dynamic Range
Maximum Input Differential Voltage (See Figure 9)
VID
VID = VAMP_P - VAMP_N
Input Common Mode Range(23), (27)
VCM
Input Offset Voltage
VOS
RS = 1.0 k, VCM = 0.0 V
Input Offset Voltage Drift(23)
Input Bias Current
VCM = 2.0 V
k
VOS/T
mV
-800
–
+800
-0.5
–
3.0
-15
–
+15
–
-10
–
-200
–
+200
V
mV
Ib
µV/°C
nA
Notes
23. This parameter is a design characteristic, not production tested.
24. As long as one input is in the common mode range there is no phase inversion on the output.
25. The hold off circuit is designed to operate over the full operating range of VSUP. The specification indicates the conditions used in
production test. Hold off is activated at VPOR or VTHVLS.
26.
28.
Desaturation is measured as the voltage drop below VSUP, thus the threshold is compared to the drain-source voltage of the external
High Side FET. See Figure 5.
As long as one input is within VCM the output is guaranteed to have the correct phase. Exceeding the common mode rails on one input
will not cause a phase inversion on the output.
Input resistance is impedance from the high side source and is referenced to VSS. Approximate tolerance is 20
29.
The current sense amplifier is unity gain stable with a phase margin of approximately 45°. See Figure 10.
27.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
11
ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
Table 4. Static Electrical Characteristics (continued)
Characteristics noted under conditions 8.0 V  VPWR = VSUP  40 V-40 C  TA  125 C, unless otherwise noted. Typical
values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
Unit
-80
–
+80
IOS/T
–
40
–
High Level with RLOAD = 10 k to VSS
VOH
VDD-0.2
–
VDD
Low Level with RLOAD = 10 k to VDD
VOL
–
–
0.2
Differential Input Resistance
RI
1.0
–
–
M
Output Short-circuit Current
ISC
5.0
–
–
mA
Common Mode Input Capacitance at 10 kHz (30), (31)
CI
–
–
10
CURRENT SENSE AMPLIFIER (CONTINUED)
Input Offset Current
IOS
IOS = IAMP_P - IAMP_N
Input Offset Current Drift (30)
nA
Output Voltage
Common Mode Rejection Ratio at DC
V
CMRR
CMRR = 20*Log ((VOUT_DIFF/VIN_DIFF) * (VIN_CM/VOUT_CM))
Large Signal Open Loop Voltage Gain (DC) (30), (31)
Nonlinearity
(30), (31)
RL = 1.0 k, CL = 500 pF, 0.3 < VO < 4.8 V, Gain = 5.0 to 15
pA/°C
AOL
pF
dB
60
80
–
–
78
–
-1.0
–
+1.0
NL
dB
%
Notes
30. This parameter is a design characteristic, not production tested.
31. Without considering any offsets such as input offset voltage, internal mismatch and assuming no tolerance error in external resistors.
34937A
12
Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
STATIC ELECTRICAL CHARACTERISTICS
Table 4. Static Electrical Characteristics (continued)
Characteristics noted under conditions 8.0 V  VPWR = VSUP  40 V-40 C  TA  125 C, unless otherwise noted. Typical
values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
High Level Input Voltage Threshold
VIH
2.1
–
–
Low Level Input Voltage Threshold
VIL
–
–
0.9
Unit
SUPERVISORY AND CONTROL CIRCUITS
Logic Inputs (Px_LS, Px_HS, EN1, EN2) (33)
V
Logic Inputs (SI, SCLK, CS) (32), (33)
V
High Level Input Voltage Threshold
VIH
2.1
–
–
Low Level Input Voltage Threshold
VIL
–
–
0.9
Input Logic Threshold Hysteresis (32)
VIHYS
Inputs Px_LS, SI, SCLK, CS, Px_HS, EN1, EN2
Input Pull-down Current, (Px_LS, SI, SCLK, EN1, EN2)
Input Capacitance
RST Pull-down Resistance
VTH_RST
0.3 VDD  VIN VDD
VPOR
SO High Level Output Voltage
VSOH
IOH = 1.0 mA
–
25
–
15
–
1.0
–
2.1
V
k
40
60
85
3.4
4.0
4.5
0.9 VDD
–
–
–
–
0.1 VDD
-1.0
–
1.0
–
15
–
0.85 VDD
–
VDD
–
–
0.5
V
V
V
µA
pF
V
VOL
IOL = 500 µA
µA
pF
VOH
IOH = -500 µA
INT Low Level Output Voltage
10
µA
CSO_T
0.0 V  VIN 5.5 V
INT High Level Output Voltage
18
ISO_LEAK_T
CS = 0.7 VDD, 0.3 VDD  VSO  0.7 VDD
SO Tri-state Capacitance (32), (36)
–
VSOL
IOL = 1.0 mA
SO Tri-state Leakage Current
8.0
RRST
Power-OFF RST Threshold, (VDD Falling)
SO Low Level Output Voltage
450
CIN
0.0 V  VIN 5.5 V
RST Threshold (35)
250
IINPU
0  VIN 0.7VDD
(32)
100
IINPD
0.3 VDD  VIN VDD
Input Pull-up Current, (CS, Px_HS) (34)
mV
V
THERMAL WARNING
Thermal Warning Temperature (32), (37)
TWARN
150
170
185
°C
Thermal Hysteresis (32)
THYST
8.0
10
12
°C
Notes
32. This parameter is guaranteed by design, not production tested.
33. Logic threshold voltages derived relative to a 3.3 V 10% system.
34. Pull-up circuits will not allow back biasing of VDD.
35.
36.
37.
There are two elements in the RST circuit: 1) one generally lower threshold enables the internal regulator; 2) the second removes the
reset from the internal logic.
This parameter applies to the OFF state (tri-stated) condition of SO is guaranteed by design but is not production tested.
The Thermal Warning circuit does not force IC shutdown above this temperature. It is possible to set a bit in the MASK register to
generate an interrupt when overtemperature is detected, and the status bit will always indicate if any of the three individual Thermal
Warning circuits in the IC sense a fault.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
13
ELECTRICAL CHARACTERISTICS
DYNAMIC ELECTRICAL CHARACTERISTICS
DYNAMIC ELECTRICAL CHARACTERISTICS
Table 5. Dynamic Electrical Characteristics
Characteristics noted under conditions 8.0 V  VPWR = VSUP  40 V, -40 C  TA  125 C, unless otherwise noted. Typical
values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
Unit
INTERNAL REGULATORS
VDD Power-up Time (Until INT High)
8.0 V VPWR
VLS Power-up Time
16 V VPWR
tPU_VDD
(38), (45)
ms
–
–
2.0
tPU_VLS
(39), (45)
ms
–
–
2.0
CHARGE PUMP
Charge Pump Oscillator Frequency
FOSC
90
125
190
kHz
Charge Pump Slew Rate(40)
SRCP
–
100
–
V/µs
–
20
35
130
265
386
–
20
35
130
265
386
–
20
35
130
265
386
GATE DRIVE
High Side Turn On Time(41)
tONH
Transition Time from 1.0 to 10 V, Load: C = 500 pF, Rg = 0, (Figure 7)
High Side Turn On Delay(42)
tD_ONH
Delay from Command to 1.0 V, (Figure 7)
High Side Turn Off Time(41)
Thermal Filter Duration (44)
ns
–
20
35
tD_OFFL
Delay from Command to 10 V, (Figure 8)
Same Phase Command Delay Match(43)
ns
tOFFL
Transition Time from 10 to 1.0 V, Load: C = 500 pF, Rg = 0, (Figure 8)
Low Side Turn Off Delay(42)
ns
tD_ONL
Delay from Command to 1.0 V, (Figure 7)
Low Side Turn Off Time(41)
ns
tONL
Transition Time from 1.0 to 10 V, Load: C = 500 pF, Rg = 0, (Figure 7)
Low Side Turn On Delay(42)
ns
tD_OFFH
Delay from Command to 10 V, (Figure 8)
Low Side Turn On Time(41)
ns
tOFFH
Transition Time from 10 to 1.0 V, Load: C = 500 pF, Rg = 0, (Figure 8)
High Side Turn Off Delay(42)
ns
ns
130
265
386
tD_DIFF
-20
0.0
+20
ns
tDUR
8.0
–
30
µs
Notes
38. The power-up time of the IC depends in part on the time required for this regulator to charge up the external filter capacitor on VDD.
39.
The power-up time of the IC depends in part on the time required for this regulator to charge up the external filter capacitors on VLS and
VLS_CAP. This delay includes the expected time for VDD to rise.
40.
The charge pump operating at 12 V VSYS, 1.0 F pump capacitor, MUR120 diodes and 47 µF filter capacitor.
41.
42.
This parameter is guaranteed by characterization, not production tested.
These delays include all logic delays except deadtime. All internal logic is synchronous with the internal clock. The total delay includes
one clock period for state machine decision block, an additional clock period for FULLON mux logic, input synchronization time and
output driver propagation delay. Subtract one clock period for operation in FULLON mode which bypasses the state machine decision
block. Synchronization time accounts for up to one clock period of variation. See Figure 6.
The maximum separation or overlap of the High and Low Side gate drives, due to propagation delays when commanding one ON and
the other OFF simultaneously, is guaranteed by design.
The output of the overtemperature comparator goes through a digital filter before generating a warning or interrupt.
This specification is based on capacitance of 0.47 µF on VDD, 2.2 µF on VLS and 2.2 µF on VLS_CAP.
43.
44.
45.
34937A
14
Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
DYNAMIC ELECTRICAL CHARACTERISTICS
Table 5. Dynamic Electrical Characteristics (continued)
Characteristics noted under conditions 8.0 V  VPWR = VSUP  40 V, -40 C  TA  125 C, unless otherwise noted. Typical
values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
Unit
tDC
0.0
–
96
%
GATE DRIVE (CONTINUED)
Duty Cycle (46), (47)
100% Duty Cycle Duration (46), (47)
tDC
–
–
Unlimited
s
Maximum Programmable Deadtime (48)
tMAX
10.2
15
19.6
µs
Overcurrent Protection Filter Time
tOC
0.9
–
3.5
µs
Rise Time (OC_OUT)
tROC
10
–
240
ns
tFOC
10
–
200
ns
Rising Edge Delay
tR
–
–
200
Falling Edge Delay
tF
–
–
350
tMATCH
–
–
100
ns
tBLANK
4.7
7.1
9.1
µs
640
937
1231
–
1.0
2.0
OVERCURRENT COMPARATOR
10% - 90%
CL = 100 pF
Fall Time (OC_OUT)
90% - 10%
CL = 100 pF
DESATURATION DETECTOR AND PHASE COMPARATOR
Phase Comparator Propagation Delay Time to 50% of VDD; CL 100 pF
Phase Comparator Match (Prop Delay Mismatch of Three Phases)
ns
CL = 100 pF (46)
Desaturation and Phase Error Blanking Time(49)
Desaturation Filter Time (Filter Time is digital)
(46)
tFILT
Fault Must be Present for This Time to Trigger
ns
CURRENT SENSE AMPLIFIER
Output Settle Time to 99% (46), (50)
RL = 1.0 k, CL = 500 pF, 0.3 V < VO < 4.8 V, Gain = 5 to 15
tSETTLE
µs
Notes
46. This parameter is guaranteed by design, not production tested.
47. As duty cycle approaches the limit of 100% or 0% there is a maximum and minimum which is not achievable due to deadtime,
propagation delays, switching times and charge time of the bootstrap capacitor (for the High Side FET). 0% is available by definition
(FET always OFF) and unlimited ON (100%) is possible as long as gate charge maintenance current is within the trickle charge pump
capacity.
48. A Minimum Deadtime of 0.0 can be set via an SPI command. When Deadtime is set via a DEADTIME command, a minimum of 1 clock
cycle duration and a maximum of 255 clock cycles is set using the internal time base clock as a reference. Commands exceeding this
value limits at this value.
49. Blanking time, tBLANK, is applied to all phases simultaneously when switching ON any output FET. This precludes false errors due to
system noise during the switching event.
50. Without considering any offsets such as input offset voltage, internal mismatch and assuming no tolerance error in external resistors.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
15
ELECTRICAL CHARACTERISTICS
DYNAMIC ELECTRICAL CHARACTERISTICS
Table 5. Dynamic Electrical Characteristics (continued)
Characteristics noted under conditions 8.0 V  VPWR = VSUP  40 V, -40 C  TA  125 C, unless otherwise noted. Typical
values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
–
–
1.0
–
–
1.0
5.0
–
–
–
30
–
–
20
–
Unit
CURRENT SENSE AMPLIFIER (CONTINUED)
Output Rise Time to 90% (52)
tIS_RISE
RL = 1.0 k, CL = 500 pF, 0.3 V < VO < 4.8 V, Gain = 5.0 to 15
Output Fall Time to 10% (52)
tIS_FALL
RL = 1.0 kCL = 500 pF, 0.3 V < VO < 4.8 V, Gain = 5.0 to 15
Slew Rate at Gain = 5.0(51)
Phase Margin at Gain = 5.0(51)
fM
(51)
V/µs
Bandwidth at Gain = 15 (51)
MHz
BWG
RL = 1.0 k, CL = 50 pF
2.0
(51)
with VIN
°
MHz
GBW
RL = 1.0 k, CL = 100 pF
Common Mode Rejection (CMR)
µs
SR(5)
RL = 1.0 k, CL = 20 pF
Unity Gain Bandwidth
µs
–
–
CMR
dB
VIN_CM = 400 mV*sin(2**freq*t)
VIN_DIF = 0.0 V, RS = 1.0 k
RFB = 15 k, VREFIN = 0.0 V
CMR = 20*Log(VOUT/VIN_CM)
Freq = 100 kHz
50
–
–
Freq = 1.0 MHz
40
–
–
Freq = 10 MHz
30
–
–
SUPERVISORY AND CONTROL CIRCUITS
EN1 and EN2 Propagation Delay
tPROP
–
–
280
ns
INT Rise Time CL = 100 pF
tRINT
10
–
250
ns
INT Fall Time CL = 100 pF
tFINT
10
–
200
ns
tPROPINT
–
–
250
ns
tTRRST
–
–
1.25
µs
INT Propagation Time
RST Transition Time (Rise and Fall)
(51) (53)
,
Notes
51. This parameter is guaranteed by design, not production tested.
52. Rise and fall times are measured from the transition of a step function on the input to 90% of the change in output voltage.
53. tTRRST is given as a design guideline. The bounds for this specification are VPWR  58 V, total capacitance on VLS > 1.0 µF.
34937A
16
Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
TIMING DIAGRAMS
Table 5. Dynamic Electrical Characteristics (continued)
Characteristics noted under conditions 8.0 V  VPWR = VSUP  40 V, -40 C  TA  125 C, unless otherwise noted. Typical
values noted reflect the approximate parameter means at TA = 25 °C under nominal conditions, unless otherwise noted.
Characteristic
Symbol
Min
fOP
–
Typ
Max
Unit
4.0
MHz
SPI INTERFACE TIMING
Maximum Frequency of SPI Operation
Internal Time Base
fTB
13
17
25
MHz
TCTB
-5.0
–
5.0
%
Falling Edge of CS to Rising Edge of SCLK (Required Setup Time)
(54)
tLEAD
100
–
–
ns
Falling Edge of SCLK to Rising Edge of CS (Required Setup Time)
(54)
Internal Time Base drift from value at 25 C (54)
tLAG
100
–
–
ns
SI to Falling Edge of SCLK (Required Setup Time)
(54)
tSISU
25
–
–
ns
Falling Edge of SCLK to SI (Required Setup Time)
(54)
tSIHOLD
25
–
–
ns
tRSI
–
5.0
–
ns
5.0
–
ns
SI, CS, SCLK Signal Rise Time
(54), (55)
SI, CS, SCLK Signal Fall Time (54), (55)
tFSI
–
Time from Falling Edge of CS to SO Low-impedance (54), (56)
tSOEN
–
55
100
ns
Time from Rising Edge of CS to SO High-impedance (54), (57)
tSODIS
–
100
125
ns
tVALID
–
80
125
ns
tDT
200
–
–
ns
Time from Rising Edge of SCLK to SO Data Valid
(54), (58)
Time from Rising Edge of CS to Falling Edge of the next CS
Notes
54.
55.
56.
57.
58.
(54)
This parameter is guaranteed by design, not production tested.
Rise and Fall time of incoming SI, CS, and SCLK signals suggested for design consideration to prevent the occurrence of double pulsing.
Time required for valid output status data to be available on SO pin.
Time required for output states data to be terminated at SO pin.
Time required to obtain valid data out from SO following the rise of SCLK with 200 pF load.
TIMING DIAGRAMS
CS
0.2 VDD
tL EA D
SCLK
ttLAG
LA G
0 .7 VD D
0 .2 VD D
tDI(S
U) tSIHOLD
DI(HO LD)
tSISU
0 .7 VD D
SI
0 .2 VD D
MSB in
tSOEN
tDO(E
N)
SO
tV A LI D
0 .7 VD D
0 .2 VD D
MSB out
tSODIS
tDO
(DIS )
LSB out
Figure 4. SPI Interface Timing
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
17
ELECTRICAL CHARACTERISTICS
TIMING DIAGRAMS
PX_HS
PX_LS
DESATURATION
FAULT
FROM DELAY
TIMER
Figure 5. Desaturation Blanking and Filtering Detail
B
PX_HS
D
MUX
STATE
MACHINE
Q
D
CLK
Q
A OUT
D
CLK
Q
PX_HS_G
CLK
DEADTIME
CONTROL
PX_LS
D
Q
PX_HS_S
1ST PULSE
D
D
CLK
CLK
Q
CLK
Q
PX_LS_G
A OUT
MUX
B
EN1
EN2
RST
Figure 6. Deadtime Control Delays
50%
Px_HS
10V
tD_ONH
Px_HS _G
tONH
1 .0 V
50%
Px_LS
10V
Px_LS_G
tD_ONL
1.0V
tONL
Figure 7. Driver Turn-on Time and Turn-on Delay
34937A
18
Analog Integrated Circuit Device Data
Freescale Semiconductor
ELECTRICAL CHARACTERISTICS
TIMING DIAGRAMS
50%
Px_HS
10V
tD_OFFH
Px_HS_G
1 .0 V tOFFH
50%
Px_ LS
1 0V
tD_OFFL
Px_LS_G
1.0V tOFFL
Figure 8. Driver Turn-off Time and Turn-off Delay
RE F
R FB P
To P rotection Circuits
AMP_P
+
V ID
AMP_N
OC_TH
AMP_O UT
Rs
+
V IN
-
R sens e
Rs
R FBN
-400mV to + 400mV
-400mV to + 400mV
0V
0V
0μS - 0.5μS
0.5μS - 50μS
0.5μS - 50μS
Figure 9. Current Amplifier and Input Waveform (VIN Voltage Across RSENSE)
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
19
ELECTRICAL CHARACTERISTICS
TIMING DIAGRAMS
Phase (degrees)
Gain (db)
Phase
Gain
Figure 10. Typical Amplifier Open-loop Gain and Phase vs. Frequency
TypicalHighSide100%OnGateVoltagewith5PAGateLoad
16
VSUP =40V
14
VSUP =24V
12
VSUP =14V
VCBOOTVHS_S (V)
10
VSUP =9V
8
6
4
2
0
50
30
10
10
30
50
70
90
110
130
150
Temperature(°C)
Figure 11. Typical High Side 100% On Gate Voltage with 5.0 µA Gate Load
34937A
20
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DESCRIPTIONS
INTRODUCTION
FUNCTIONAL DESCRIPTIONS
INTRODUCTION
The 34937A provides an interface between an MCU and
the external FETs used to drive three phase motors. A typical
external FET may have an on resistance of 4.0 m or less
and could require a gate charge of over 400 nC to fully turn
on. The IC can operate in 12 to 48 V environments.
There are many methods for controlling three phase motor
systems, so the IC enforces few constraints in driving the
FETs. The 34937A does however provide deadtime (crossover) blanking and logic in order to protect the external FETs.
Under special configurations, both of these features can be
overridden, allowing both FETs in a phase to be
simultaneously enabled.
An SPI port is used to configure the 34937A’s modes.
FUNCTIONAL PIN DESCRIPTION
PHASE A (PHASEA)
This pin is the totem pole output of the Phase A
comparator. This output is low when the voltage on Phase A
high side source (source of the high side load FET) is less
than 50 percent of VSUP.
connected to a polarity protected supply. This input should
never be connected to a supply greater than 40 V.
If the charge pump is not required this pin may be left
floating.
VSUP INPUT (VSUP)
POWER GROUND (PGND)
This pin is power ground for the charge pump. It should be
connected to VSS, however routing to a single point ground
on the PCB may help to isolate charge pump noise.
ENABLE 1 AND ENABLE 2 (EN1, EN2)
Both of these logic signal inputs must be high to enable
any gate drive output. When either or both are low, the
internal logic (SPI port, etc.) still functions normally, but all
gate drives are forced off (external power FET gates pulled
low). The signal is asynchronous.
When EN1 and EN2 return high to enable the outputs,
each LS driver must be pulsed ON before the corresponding
HS driver can be commanded ON. This ensures that the
bootstrap capacitors are charged. See Initialization
Requirements on page 38.
RESET (RST)
When the reset pin is low the integrated circuit (IC) is in a
low power state. In this mode all outputs are disabled, internal
bias circuits are turned off, and a small pull-down current is
applied to the output gate drives. The internal logic will be
reset within 77 ns of RESET going low. When RST is low, the
IC will consume minimal current.
CHARGE PUMP OUT (PUMP)
This pin is the switching node of the charge pump circuit.
The output of the internal charge pump support circuit. When
the charge pump is used, it is connected to the external
pumping capacitor. This pin may be left floating if the charge
pump is not required.
CHARGE PUMP INPUT (VPUMP)
This pin is the input supply for the charge pump circuit.
When the charge pump is required, this pin should be
The supply voltage pin should be connected to the
common connection of the high side FETs. It is the reference
bias for the Phase Comparators and Desaturation
Comparator. It is also used to provide power to the internal
steady state trickle charge pump and to energize the hold off
circuit.
PHASE B (PHASEB)
This pin is the totem pole output of the Phase B
comparator. This output is low when the voltage on Phase B
high side source (source of the high side load FET) is less
than 50 percent of VSUP.
PHASE C (PHASEC)
This pin is the totem pole output of the Phase C
comparator. This output is low when the voltage on Phase C
high side source (source of the high side load FET) is less
than 50 percent of VSUP.
PHASE A HIGH SIDE INPUT (PA_HS)
This input logic signal pin enables the high side driver for
Phase A. The signal is active low, and is pulled up by an
internal current source.
PHASE A LOW SIDE INPUT (PA_LS)
This input logic signal pin enables the low side driver for
Phase A. The signal is active high, and is pulled down by an
internal current sink.
VDD VOLTAGE REGULATOR (VDD)
VDD is an internally generated 5.0 V supply. The internal
regulator provides continuous power to the IC and is a supply
reference for the SPI port. A 0.47 µF (min) decoupling
capacitor must be connected to this pin.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
21
FUNCTIONAL DESCRIPTIONS
INTRODUCTION
This regulator is intended for internal IC use and can
supply only a small (1.0 mA) external load current.
A power-on-reset (POR) circuit monitors this pin and until
the voltage rises above the threshold, the internal logic will be
reset; driver outputs will be tri-stated and SPI communication
disabled.
The VDD regulator can be disabled by asserting the RST
signal low. The VDD regulator is powered from the VPWR
pin.
PHASE B HIGH SIDE CONTROL INPUT (PB_HS)
This pin is the input logic signal, enabling the high side
driver for Phase B. The signal is active low, and is pulled up
by an internal current source.
PHASE B LOW SIDE INPUT (PB_LS)
This pin is the input logic signal, enabling the low side
driver for Phase B. The signal is active high, and is pulled
down by an internal current sink.
INTERRUPT (INT)
PHASE C HIGH SIDE INPUT (PC_HS)
This input logic pin enables the high side driver for Phase
C. This signal is active low, and is pulled up by an internal
current source.
AMPLIFIER OUTPUT (AMP_OUT)
This pin is the output for the current sensing amplifier. It is
also the sense input to the overcurrent comparator.
AMPLIFIER INVERTING INPUT (AMP_N)
The inverting input to the current sensing amplifier.
AMPLIFIER NON-INVERTING INPUT (AMP_P)
The non-inverting input to the current sensing amplifier.
OVERCURRENT COMPARATOR OUTPUT
(OC_OUT)
The overcurrent comparator output is a totem pole logic
level output. A logic high indicates an overcurrent condition.
OVERCURRENT COMPARATOR THRESHOLD
(OC_TH)
The Interrupt pin is a totem pole logic output. When a fault
is detected, this pin will pull high until it is cleared by
executing the Clear Interrupt command via the SPI port. The
faults capable of causing an interrupt can be masked via the
MASK0 and MASK1 SPI registers to customize the
response.
This input sets the threshold level of the overcurrent
comparator.
CHIP SELECT (CS)
VSS is the ground reference for the logic interface and
power supplies.
Chip select is a logic input that frames the SPI commands
and enables the SPI port. This signal is active low, and is
pulled up by an internal current source.
GROUND (GND0,GND1)
SERIAL IN (SI)
The Serial In pin is used to input data to the SPI port.
Clocked on the falling edge of SCLK, it is the most significant
bit (MSB) first. This pin is pulled down by an internal current
sink.
VOLTAGE SOURCE SUPPLY (VSS)
These two pins are connected internally to VSS by a 1.0 
resistor. They provide device substrate connections and also
the primary return path for ESD protection.
VLS REGULATOR CAPACITOR (VLS_CAP)
This logic input is the clock is used for the SPI port. The
SCLK typically runs at 3.0 MHz (up to 5.0 MHz) and is pulled
down by an internal current sink.
This connection is for a capacitor which will provide a lowimpedance for switching currents on the gate drive. A low
ESR decoupling capacitor, capable of sourcing the pulsed
drive currents must be connected between this pin and VSS.
This is the same DC node as VLS, but it is physically
placed on the opposite end of the IC to minimize the source
impedance to the gate drive circuits.
SERIAL OUT (SO)
PHASE C LOW SIDE SOURCE (PC_LS_S)
Output data for the SPI port streams from this pin. It is tristated until CS is low. New data appears on rising edges of
SCLK in preparation for latching by the falling edge of SCLK
on the master.
The phase C low side source is the pin used to return the
gate currents from the low side FET. Best performance is
realized by connecting this node directly to the source of the
low side FET for phase C.
PHASE C LOW SIDE INPUT (PC_LS)
PHASE C LOW SIDE GATE (PC_LS_G)
This input logic pin enables the low side driver for Phase
C. This pin is an active high, and is pulled down by an internal
current sink.
This is the gate drive for the Phase C low side output FET.
It provides high-current through a low-impedance to turn on
and off the low side FET. A low-impedance drive ensures
transient currents do not overcome an off-state driver and
SERIAL CLOCK (SCLK)
34937A
22
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DESCRIPTIONS
INTRODUCTION
allow pulses of current to flow in the external FET. This output
has also been designed to resist the influence of negative
currents.
PHASE C HIGH SIDE SOURCE (PC_HS_S)
The source connection for the Phase C high side output
FET is the reference voltage for the gate drive on the high
side FET and also the low-voltage end of the bootstrap
capacitor.
PHASE C HIGH SIDE GATE (PC_HS_G)
This is the gate drive for the Phase C high side output FET.
This pin provides the gate bias to turn the external FET on or
off. The gate voltage is limited to about 15 V above the FET
source voltage. A low-impedance drive is used, ensuring
transient currents do not overcome an off-state driver and
allow pulses of current to flow in the external FETs. This
output has also been designed to resist the influence of
negative currents.
source voltage. A low-impedance drive is used, ensuring
transient currents do not overcome an off-state driver and
allow pulses of current to flow in the external FETs. This
output has also been designed to resist the influence of
negative currents.
PHASE B BOOTSTRAP (PB_BOOT)
This is the bootstrap capacitor connection for phase B. A
capacitor connected between PC_HS_S and this pin
provides the gate voltage and current to drive the external
FET gate. Typically, the bootstrap capacitor selection is 10 to
20 times the gate capacitance. The voltage across this
capacitor is limited to about 15 V.
PHASE A LOW SIDE SOURCE (PA_LS_S)
The Phase A low side source is the pin used to return the
gate currents from the low side FET. Best performance is
realized by connecting this node directly to the source of the
low side FET for phase A.
PHASE C BOOTSTRAP (PC_BOOT)
PHASE A LOW SIDE GATE (PA_LS_G)
This is the bootstrap capacitor connection for Phase C. A
capacitor connected between PC_HS_S and this pin
provides the gate voltage and current to drive the external
FET gate. Typically, the bootstrap capacitor selection is 10 to
20 times the gate capacitance. The voltage across this
capacitor is limited to about 15 V.
This is the gate drive for the Phase A low side output FET.
It provides high-current through a low-impedance to turn on
and off the low side FET. A low-impedance drive ensures
transient currents do not overcome an off-state driver and
allow pulses of current to flow in the external FET. This output
has also been designed to resist the influence of negative
currents.
PHASE B LOW SIDE SOURCE (PB_LS_S)
The Phase B low side source is the pin used to return the
gate currents from the Low Side FET. Best performance is
realized by connecting this node directly to the source of the
low side FET for Phase B.
PHASE B LOW SIDE GATE (PC_LS_G)
This is the gate drive for the Phase B low side output FET.
It provides high-current through a low-impedance to turn on
and off the low side FET. A low-impedance drive ensures
transient currents do not overcome an off-state driver and
allow pulses of current to flow in the external FET. This output
has also been designed to resist the influence of negative
currents.
PHASE B HIGH SIDE SOURCE (PB_HS_S)
The source connection for the Phase B high side output
FET is the reference voltage for the gate drive on the high
side FET and also the low-voltage end of the bootstrap
capacitor.
PHASE B HIGH SIDE GATE (PB_HS_G)
This is the gate drive for the Phase B high side output FET.
This pin provides the gate bias to turn the external FET on or
off. The gate voltage is limited to about 15 V above the FET
PHASE A HIGH SIDE SOURCE (PA_HS_S)
The source connection for the Phase A high side output
FET is the reference voltage for the gate drive on the high
side FET and also the low-voltage end of the bootstrap
capacitor.
PHASE A HIGH SIDE GATE (PA_HS_G)
This is the gate drive for the Phase A high side output FET.
This pin provides the gate bias to turn the external FET on or
off. The gate voltage is limited to about 15 V above the FET
source voltage. A low-impedance drive is used, ensuring
transient currents do not overcome an off-state driver and
allow pulses of current to flow in the external FETs. This
output has also been designed to resist the influence of
negative currents.
PHASE A BOOTSTRAP (PA_BOOT)
This is the bootstrap capacitor connection for phase A. A
capacitor connected between PC_HS_S and this pin
provides the gate voltage and current to drive the external
FET gate. Typically, the bootstrap capacitor selection is 10 to
20 times the gate capacitance. The voltage across this
capacitor is limited to about 15 V.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
23
FUNCTIONAL DESCRIPTIONS
INTRODUCTION
VLS REGULATOR (VLS)
VLS is the gate drive power supply regulated at
approximately 15 V. This is an internally generated supply
from VPWR. It is the source for the low side gate drive
voltage, and also the High Side bootstrap source. A low ESR
decoupling capacitor, capable of sourcing the pulsed drive
currents, must be connected between this pin and VSS.
VPWR INPUT (VPWR)
VPWR is the power supply input for VLS and VDD. Current
flowing into this input recharges the bootstrap capacitors as
well as supplying power to the low side gate drivers and the
VDD regulator. An internal regulator regulates the actual gate
voltages. This pin can be connected to system supply voltage
if power dissipation is not a concern.
EXPOSED PAD (EP)
The primary function of the exposed pad is to conduct heat
out of the device. This pad may be connected electrically to
the substrate of the device.The device will perform as
specified with the exposed pad un-terminated (floating).
However, it is recommended that the exposed pad be
terminated to pin 29 (VSS) and the system ground.
34937A
24
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
MC34937 - Functional Block Diagram
Integrated Supply
Main Charge Pump
5.0 V Regulator
Trickle Charge Pump
VLS Regulator
Sensing & Protection
Hold-off
Undervoltage
Temperature
De-sat
Current Sense
Phase
Overcurrent
High Side
and
Low Side
Output
Pre-drivers
Logic & Control
Fault Register
Dead Time
Phase Control
Mode Control
SPI Communication
Integrated Supply
Sensing & Protection
Logic & Control
Drivers
Figure 12. Functional Internal Block Description
12 µs. Calibration of the delay, because of internal IC
All functions of the IC can be described as the following
variations, is performed via the SPI.
five major functional blocks:
• Enabling of simultaneous operation of high side and
• Logic Inputs and Control
low side FETs—Normally, both FETs would not be
• Integrated Supply
enabled simultaneously. However, for certain applications
• High Side and Low Side Drivers
where the load is connected between the high side and
• Sensing and Protection
low side FETs, this could be advantageous. If this mode is
enabled, the blanking time delay will be disabled. A
LOGIC INPUTS AND CONTROL
sequence of commands may be required to enable this
This section contains the SPI port, control logic, and shootfunction to prevent inadvertent enabling. In addition, this
through timers.
command can only be executed once after reset to enable
or disable simultaneous turn-on.
The IC logic inputs have Schmitt trigger inputs with
hysteresis. Logic inputs are 3.0 V compatible. The logic
• Setting of various operating modes of the IC and
outputs are driven from the internal supply of approximately
enabling of interrupt sources.
5.0 V.
The 34937A allows different operating modes to be set
and locked by an SPI command (FULLON, Desaturation
The SPI registers and functionality is described completely
Fault, Zero Deadtime). SPI commands can also determine
in the LOGIC COMMANDS AND REGISTERS section of this
how the various faults are (or are not) reported.
document. SPI functionality includes the following:
•
Read back of internal registers.
• Programming of deadtime delay—This delay is
The
status of the 34937A status registers can be read
adjustable in approximately 50 ns steps from 0 ns to
back by the Master (DSP or MCU).
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
25
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
The Px_HS and Px_LS logic inputs are edge sensitive.
This means the leading edge on an input will cause the
complementary output to immediately turn off and the
selected one to turn on after the deadtime delay as illustrated
in Figure 13.
The deadtime delay timer always starts at the time a FET
is commanded off and prevents the complementary FET from
being commanded on until after the deadtime has elapsed.
Commands to turn on the complementary FET after the
deadtime has elapsed are executed immediately without any
further delay (see Figure 6 and Figure 13).
Low Side drivers switch power from VLS to the gates of the
Low Side FETs. The Low Side drivers are capable of
providing a typical peak current of 2.0 A. This gate drive
current may be limited by external resistors in order to
achieve a good trade-off between the efficiency and EMC
(Electro-Magnetic Compatibility) compliance of the
application. the Low Side driver uses high side PMOS for turn
on and low side isolated LDMOS for turn off. The circuit
ensures the impedance of the driver remains low, even
during periods of reduced current. Current limit is blanked
immediately after subsequent input state change in order to
ensure device stays off during dV/dt transients.
HIGH SIDE DRIVERS
PA _HS
PA_LS
De adt ime
De lay
PA_HS_G
PA_LS_G
Figure 13. Edge Sensitive Logic Inputs (Phase A)
LOW SIDE AND BOOTSTRAP SUPPLY (VLS)
This is the portion of the IC providing current to recharge
the bootstrap capacitors. It also supplies the peak currents
required for the low side gate drivers.
The power for the gate drive circuits is provided by VLS
which is supplied from the VPWR pin. This pin can be
connected to system supply voltage and is capable of
withstanding up to the full transient voltage of the system.
However, the IC only requires a low-voltage supply on this
pin, typically 13 to 16 V. Higher voltages on this pin will
increase the IC power dissipation.
In 12 V systems the supply voltage can fall as low as 6.0 V.
This limits the gate voltage capable of being applied to the
FETs and reduces system performance due to the higher
FET on-resistance. To allow a higher gate voltage to be
supplied, the IC also incorporates a charge pump. The
switches and control circuitry are internal; the capacitors and
diodes are external (see Figure 22).
LOW SIDE DRIVERS
These three drivers turn on and off the external Low Side
FETs. The circuits provide a low-impedance drive to the gate,
ensuring the FETs remain off in the presence of high dV/dt
transients on their drains. Additionally, these output drivers
isolate the other portions of the IC from currents capable of
being injected into the substrate due to rapid dV/dt transients
on the FET drains.
These three drivers switch the voltage across the
bootstrap capacitor to the external high side FETs. The
circuits provide a low-impedance drive to the gate, ensuring
the FETs remain off in the presence of high dV/dt transients
on their sources. Further, these output drivers isolate the
other portions of the IC from currents capable of being
injected into the substrate due to rapid dV/dt transients on the
FETs.
The high side drivers deliver power from their bootstrap
capacitor to the gate of the external high side FET, thus
turning the high side FET on. The high side driver uses a level
shifter, which allows the gate of the external high side FET to
be turned off by switching to the high side FET source.
The gate supply voltage for the high side drivers is
obtained from the bootstrap supply, so, a short time is
required after the application of power to the IC to charge the
bootstrap capacitors. To ensure this occurrence, the internal
control logic will not allow a high side switch to be turned on
after entering the ENABLE state until the corresponding low
side switch is enabled at least once. Caution must be
exercised after a long period of inactivity of the low side
switches to verify the bootstrap capacitor is not discharged. It
will be charged by activating the low side switches for a brief
period, or by attaching external bleed resistors from the
HS_S pins to GND. See Initialization Requirements on page
38.
In order to achieve a 100% duty cycle operation of the High
Side external FETs, a fully integrated trickle charge pump
provides the charge necessary to maintain the external FET
gates at fully enhanced levels. The trickle charge pump has
limited ability to supply external leakage paths while
performing it’s primary function. The graph in Figure 11
shows the typical margin for supplying external current loads.
These limits are based on maintaining the voltage at CBOOT
at least 3.0 V greater than the voltage on the HS_S for that
phase. If this voltage differential becomes less than 3.0 V, the
corresponding high side FET will most likely not remain fully
enhanced and the high side driver may malfunction due to
insufficient bias voltage between CBOOT and HS_S.
34937A
26
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
The slew rate of the external output FET is limited by the
driver output impedance, overall (external and internal) gate
resistance and the load capacitance. To ensure the Low Side
FET is not turned on by a large positive dV/dt on the drain of
the Low Side FET, the turn-on slew rate of the High Side
should be limited. If the slew rate of the High Side is limited
by the gate-drain capacitance of the High Side FET, then the
displacement current injected into the Low Side gate drive
output will be approximately the same value. Therefore, to
ensure the Low Side drivers can be held off, the voltage drop
across the Low Side gate driver must be lower than the
threshold voltage of the Low Side FET (see Figure 14).
Similarly, during large negative dV/dt, the High Side FET
will be able to remain off if its gate drive Low Side switch,
develops a voltage drop less than the threshold voltage of the
High Side FET. The gate drive Low Side switch discharges
the gate to the source.
Additionally, during negative dV/dt the Low Side gate drive
could be forced below ground. The Low Side FETs must not
inject detrimental substrate currents in this condition.
The occurrence of these cases depends on the polarity of
the load current during switching.
34937A
33927
Px_HS_S
VLS
LS
Control
Phase x
Output
Low
-Side
Driver
Zo
D
Discrete
FET
Package
CDG
iCDG
G
Px_LS_G
-
+
CDS
Rg
CGS
S
Px_LS_S
Phase
Return
DRIVER FAULT PROTECTION
The 34937A IC integrates several protection mechanisms
against various faults. The first of them is the Current Sense
Amplifier with the Overcurrent Comparator. These two blocks
are common for all three driver phases.
Current Sense Amplifier
This amplifier is usually connected as a differential
amplifier (see Figure 9). It senses a current flowing through
the external FETs as a voltage across the current sense
resistor RSENSE. Since the amplifier common mode range
does not extend below ground, it is necessary to use an
external reference to permit measuring both positive and
negative currents.
The amplifier output can be monitored directly (e.g. by the
microcontroller’s ADC) at the AMP_OUT pin, providing the
means for closed loop control with the 34937A.
The output voltage is internally compared with the
Overcurrent Comparator threshold voltage (see Figure 22).
Overcurrent Comparator
The amplified voltage across RSENSE is compared with the
pre-set threshold value by the overcurrent comparator input.
If the Current Sense Amplifier output voltage exceeds the
threshold of the Overcurrent Comparator it would change the
status of its output (OC_OUT pin) and the fault condition
would be latched (see Figure 18).
The occurrence of this fault would be signalled by the
return value of the Status Register 0. If the proper Interrupt
Mask has been set, this fault condition will generate an
interrupt - the INT pin will be asserted High. The INT will be
held in the High state until the fault is removed, and the
appropriate bit in the Status Register 0 is cleared by the
CLINT0 command. This fault reporting technique is
described in detail in the Logic Commands and Registers
section.
Desaturation Detector
Px_HS_G
Deadtime
Px_LS_G
Phase x Output Voltage
VSUP
dV/dt
-VD
The Desaturation Detector is a comparator integrated into
the output driver of each phase channel. It provides an
additional means to protect against “Short-to-Ground” fault
condition. A short to ground is detected by an abnormally
high-voltage drop in VDS of the High Side FET. Note that if
the gate-source voltage of the High Side FET drops below
saturation, the device will go into linear mode of conduction
which can also cause a desaturation error.
Figure 14. Positive DV/dt Transient
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
27
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
V SUP
VSUP
VLS
3x
VLS
3x
T-Lim
T-Lim
VSUP
High Px_BOOT
-Side
Driver
HS
Control
+
-
Desat.
Comp.
VSUP
Px_HS_G
1.4V
Phase x
Output
Phase
Comp.
R
Phase x Output
Shorted to Ground
(Low-Side
FET Shorted)
Low
-Side
Driver
LS
Control
VSUP
Phase
Comp.
R
Low
-Side
Driver
LS
Control
R
Px_LS_S
To Current
Sense Amplif.
VLS_CAP
Px_HS_G
Phase
Return
Px_LS_S
RSense
tFILT
RSense
Deadtime
tBLANK
Px_LS_G
Correct Phase x Output Voltage
VSUP
Phase x Output Voltage Shorted to VSUP
0.5V SUP
0.5VSUP
Phase x Output
Voltage Shorted to Ground
PHASEx
To Current
Sense Amplif.
VLS_CAP
Phase
Return
Px_HS_G
tBLANK
Deadtime
Px_LS_G
-V D
Phase x
Output
Px_LS_G
Px_LS_G
R
V SUP
Phase x Output
Shorted to VSUP
(High-Side
FET Shorted)
Px_HS_G
+
1. 4V
-
Px_HS_S
Px_HS_S
VSUP
Desat.
Comp.
High Px_BOOT
-Side
Driver
HS
Control
Correct Phase x Output Voltage
-VD
Correct
Fault
Fault
PHASEx
Correct
Phase Error
Desaturation Error
Figure 15. Short to Ground Detection
When switching from Low Side to High Side, the High Side
will be commanded ON after the end of the deadtime. The
deadtime period starts when the Low Side is commanded
OFF. If the voltage at Px_HS_S is less than 1.4V below VSUP
after the blanking time (tBLANK) a desaturation fault is
initiated. An additional 1.0 s digital filter is applied from the
initiation of the desaturation fault before it is registered, and
all phase drivers are turned OFF (Px_HS_G clamped to
Px_HS_S and Px_LS_G clamped to Px_LS_S). If the
desaturation fault condition clears before the filter time
expires, the fault is ignored and the filter timer resets.
Valid faults are registered in the fault status register, which
can be retrieved by way of the SPI. Additional SPI commands
will mask the INT flag and disable output stage shutdown,
due to desaturation and phase errors. See the Logic
Commands and Registers section for details on masking INT
behavior and disabling the protective function.
Phase Error
Figure 16. Short to Supply Detection
Phase Comparator
Faults could also be detected as Phase Errors. A phase
error is generated if the output signal (at Px_HS_S) does not
properly reflect the drive conditions.
A phase error is detected by a Phase Comparator. The
Phase Comparator compares the voltage at the Px_HS_S
node with a reference of one half the voltage at the VSUP pin.
A High Side phase error (which will also trigger the
Desaturation Detector) occurs when the High Side FET is
commanded on, and Px_HS_S is still low at the end of the
deadtime and blanking time duration. Similarly, a LS phase
error occurs when the Low Side FET is commanded on, and
the Px_HS_S is still high at the end of the deadtime and
blanking time duration.
The Phase Error Flag is the triple OR of phase errors from
each phase. Each phase error is the OR of the High Side and
Low Side phase errors. This flag can generate an interrupt if
the appropriate mask bit is set. The INT will be held in the
High state until the fault is removed, and the appropriate bit
in the Status Register 0 is cleared by the CLINT1 command.
This fault reporting mechanism is described in detail in the
Logic Commands and Registers section.
34937A
28
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
VLS UNDER VOLTAGE
CHARGE PUMP
Since VLS supplies both the gate driver circuits and the
gate voltage, it is critical that it maintains sufficient potential
to place the power stage FETs in saturation. Since proper
operation cannot continue with insufficient levels, a low VLS
condition will shutdown driver operation. The VLS Under
Voltage threshold is between 7.5 V and 8.5 V. When a
decreasing level reaches the threshold, both the HS and the
LS output gate circuit drive the gates OFF for about 8us
before reducing the drive to hold off levels. Since low VLS is
a condition for turning on the Hold Off circuit, Hold Off then
provides a weak pull-down on all gates. A filter timeout of
about 700ns insures that noise on VLS will not cause
premature protective action.
When VLS rises above this threshold again, the LS Gate
immediately follows the level of the input. However, a short
initialization sequence must be executed to restore operation
of the HS Gate. (See Initialization Requirements on page 38)
Since VLS is no longer under voltage, the Hold Off circuit is
turned off and the HS Gate will be in a high-impedance state
until the LS Gate responds to an input command to turn off.
The Charge Pump circuit provides the basic switching
elements required to implement a charge pump, when
combined with external capacitors and diodes for enhanced
low-voltage operation.
When the 34937A is connected per the typical application
using the charge pump (see Figure 22), the regulation path
for VLS includes the charge pump and a linear regulator. The
regulation set point for the linear regulator is nominally at
15.34 V. As long as VLS output voltage (VLSOUT) is greater
than the VLS analog regulator threshold (VLSATH) minus
VTHREG, the charge pump is not active.
If VLSOUT < VLSATH – VTHREG the charge pump turns ON
until VLSOUT > VLSATH – VTHREG + VHYST
VHYST is approximately 200 mV. VLSATH will not interfere
with this cycle even when there is overlap in the thresholds,
due to the design of the regulator system.
The maximum current the charge pump can supply is
dependent on the pump capacitor value and quality, the
pump frequency (nominally 130 kHz), and the Rdson of the
pump FETs. The effective charge voltage for the pump
capacitor would be VSYS – 2 * VDIODE. The total charge
transfer would then be CPUMP * (VSYS – 2*VDIODE).
Multiplying by the switch frequency gives the theoretical
current the pump can transfer: FPUMP * CPUMP * (VSYS –
2*VDIODE).
NOTE: There is also another smaller, fully integrated
charge pump (Trickle Charge Pump - see Figure 2), which is
used to maintain the High Side drivers’ gate VGS in 100
percent duty cycle modes.
HOLD OFF CIRCUIT
The IC guarantees the output FETs are turned off in the
absence of VDD or VPWR by means of the Hold off circuit. A
small current source, generated from VSUP, typically
100 µA, is mirrored and pulls all the output gate drive pins low
when VDD is less than about 3.0 V, RST is active (low), or
when VLS is lower than the VLS_Disable threshold. A
minimum of 3.0 V is required on VSUP to energize the Hold
off circuit.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
29
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
RESET AND ENABLE
The 34937A has three power modes of operation
described in Table 6. There are three global control inputs
(RST, EN1, EN2), which together with the status of VDD, VLS
and DESAT/PHASE faults control the behavior of the IC.
The operating status of the IC can be described by the
following five modes:
• Sleep Mode - When RST is low, the IC is in Sleep
mode. The current consumption of the IC is at minimum.
• Standby Mode - The RST input is high while one of the
Enable inputs is low. The IC is fully biased up and
operating, all the external FETs are actively turned off
by both High Side and Low Side gate drives. The IC is
ready to enter the Enable Mode.
• Initialization Mode - When EN1, EN2 and RST all go
high, the device enters the Initialization Mode. Toggling
the LS and then the HS initializes the driver and normal
operation in the Enable Mode begins. (See Initialization
Requirements on page 40)
• Enable Mode - After initialization is complete, the
device goes into the Enable Mode and operates
normally. Normal operation continues in this mode as
long as both enable pins and RST are high.
• Fault Protection Mode - If a protective fault occurs
(either Desat/Phase or VLS UV) the device enters a
Fault Protection Mode. After a fault clears, the device
requires initialization again before resuming normal
Enable Mode operation.
Table 6. Functions of RST, EN1 and EN2 Pins
RST
EN1, EN2
Mode of Operation (Driver Condition)
0
xx
Sleep Mode - in this mode (low quiescent current) the driver output stage is switched-off with a weak pull-down. All error
and SPI registers are cleared. The internal 5.0 V regulator is turned off and VDD is pulled low. All logic outputs except
SO are clamped to VSS.
1
0x
Standby Mode - IC fully biased up and all functions are operating, the output drivers actively turn off all of the external
FETs (after initialization). The SPI port is functional. Logic level outputs are driven with low-impedance. SO is highimpedance unless CS is low. VDD, Charge Pump and VLS regulators are all operating. The IC is ready to move to Enable
Mode.
x0
1
11
Initialization Mode - Low Side Drivers are enabled, SPI is fully operational. Ready for initialization (See Initialization
Requirements on page 38).
Enable Mode - (normal operation). Drivers are enabled; output stages follow the input command. After Enable, outputs
require a pulse on Px_LS before corresponding HS outputs will turn on in order to charge the bootstrap capacitor. All
error pin and register bits are active if detected.
Fault Protection Mode - Drivers are turned OFF or disabled per the fault and protection mode registers. Recovery
requires initialization (See Initialization Requirements on page 38).
Table 7. Functional Ratings
(TJ = -40 °C to 150 °C and supply voltage range VSUP = VPWR = 5.0 to 45 V, C = 0.47 µF)
Characteristic
Value
Default State of input pin Px_LS, EN1, EN2, RST, SI, SCLK, if left open (59)
Low (<1.0 V)
(Driver output is switched off, high-impedance mode)
Default State of input pin Px_HS, CS if left open (59)
High (>2.0 V)
(Driver output is switched off, high-impedance mode)
Notes
59. To assure a defined status for all inputs, these pins are internally biased by pull-up/down current sources.
34937A
30
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
Sleep Mode
Sleep
Y
RST
N
Standby Mode
STBY
Initialization
N
EN
ENABLE LS
Y
Enable (Normal) Mode
N
LS Toggle
Y
HS Toggle
ENABLE
Y
HS
N
DESAT
Disabled
N
DESAT/
PHASE
Driver OFF
Y
VLS UV
DESAT/
PHASE
N
Y
N
Y
N
Fault Protection
Disable Driver
Holdoff Active
Driver OFF
Y
VLS UV
N
Y
EN
N
Y
Y
RST
N
Figure 17. Device Operational Flow Diagram
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
31
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
LOGIC COMMANDS AND REGISTERS
COMMAND DESCRIPTIONS
The IC contains internal registers to control the various
operating parameters, modes, and interrupt characteristics.
These commands are sent and status is read via 8-bit SPI
commands. The IC will use the last eight bits in an SPI
transfer, so devices can be daisy-chained. The first three bits
in an SPI word can be considered to be the Command with
the trailing five bits being the data.
The SPI logic will generate a framing error and ignore the
SPI message if the number of received bits is not eight or if it
is not a multiple of eight.
After RST, the first SPI result returned is Status Register 0.
Table 8. Command List
Command
Name
Description
000x xxxx
NULL
These commands are used to read IC status. These commands do not change any internal IC status. Returns
Status Register 0-3, depending on sub command.
0010 xxxx
MASK0
Sets a portion of the interrupt mask using lower four bits of command. A “1” bit enables interrupt generation
for that flag. INT remains asserted if uncleared faults are still present. Returns Status Register 0.
0011 xxxx
MASK1
Sets a portion of the interrupt mask using lower four bits of command. A “1” bit enables interrupt generation
for that flag. INT remains asserted if uncleared faults are still present. Returns Status Register 0.
010x xxxx
MODE
Enables Desat/Phase Error Mode. Enables FULLON Mode. Locks further Mode changes. Returns Status
Register 0.
0110 xxxx
CLINT0
Clears a portion of the fault latch corresponding to MASK0 using lower four bits of command. A 1 bit clears
the interrupt latch for that flag. INT remains asserted if other unmasked faults are still present. Returns Status
Register 0.
0111 xxxx
CLINT1
Clears a portion of the fault latch corresponding to MASK1 using lower four bits of command. A 1 bit clears
the interrupt latch for that flag. INT remains asserted if other unmasked faults are still present. Returns Status
Register 0.
100x xxxx
DEADTIME
Set deadtime with calibration technique. Returns Status Register 0.
FAULT REPORTING AND INTERRUPT
GENERATION
Different fault conditions described in the previous
chapters can generate an interrupt - INT pin output signal
asserted high. When an interrupt occurs, the source can be
read from Status Register 0, which is also the return word of
most SPI messages.
Faults are latched on occurrence, and the interrupt and
faults are only cleared by sending the corresponding CLINTx
command. A fault that still exists will continue to assert an
interrupt.
Note: If there are multiple pending interrupts, the INT line
will not toggle when one of the faults is cleared. Interrupt
processing circuitry on the host must be level sensitive to
correctly detect multiple simultaneous interrupt.
Thus, when an interrupt occurs, the host can query the IC
by sending a NULL command; the return word contains flags
indicating any faults not cleared since the CLINTx command
was last written (rising edge of CS) and the beginning of the
current SPI command (falling edge of CS). The NULL
command causes no changes to the state of any of the fault
or mask bits.
The logic clearing the fault latches occurs only when:
1. A valid command had been received(i.e. no framing
error);
2. A state change did not occur during the SPI message
(if the bit is being returned as a 0 and a fault change
occurs during the middle of the SPI message, the latch
will remain set). The latch is cleared on the trailing
(rising) edge of the CS pulse. Note, to prevent missing
any faults the CLINTx command should not generally
clear any faults without being observed; i.e. it should
only clear faults returned in the prior NULL response.
34937A
32
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
NULL COMMANDS
This command is sent by sending binary 000x xxxx data. This can be used to read IC status in the SPI return word. Message
000x xx00 reads Status Register 0. Message 000x xx01 through 000x xx11 read additional internal registers.
Table 9. NULL Commands
SPI Data Bits
7
6
5
4
3
2
1
0
Write
0
0
0
x
x
x
0
0
Reset
NULL Commands are described in detail in the STATUS REGISTERS section of this document.
MASK Command
This is the mask for interrupts. A bit set to “1” enables the corresponding interrupt. Because of the number of MASK bits, this
register is in two portions:
1. MASK0
2. MASK1
Both are accessed with 0010 xxxx and 0011 xxxx patterns respectively. Figure 18 illustrates how interrupts are enabled and
faults cleared.
CLINT0 and CLINT1 have the same format as MASK0 and MASK1 respectively, but the action is to clear the interrupt latch
and status register 0 bit corresponding to the lower nibble of the command.
Table 10. MASK0 Register
SPI Data Bits
7
6
5
4
3
2
1
0
Write
0
0
1
0
x
x
x
x
1
1
1
1
Reset
INTERRUPT HANDLING
From MASKx:N Register
MASK Bit
To Status Register
INT Source
Various Faults
INT Clear
From Clint Command
net N
Fault
S
Latch
R
INT
net 0
Figure 18. Interrupt Handling
Table 11. MASK1 Register
SPI Data Bits
7
6
5
4
3
2
1
0
Write
0
0
1
1
x
x
x
x
1
1
1
1
Reset
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
33
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Table 12. Setting Interrupt Masks
Mask:bit
Description
MASK0:0
Overtemperature on any gate drive output generates an interrupt if this bit is set.
MASK0:1
Desaturation event on any output generates an interrupt if this bit is set.
MASK0:2
VLS undervoltage generates an interrupt if this bit is set.
MASK0:3
Overcurrent Error–if the overcurrent comparator threshold is exceeded, an interrupt is generated.
MASK1:0
Phase Error–if any Phase comparator output is not at the expected value when an output is command on, an interrupt is
generated. This signal is the XOR of the phase comparator output with the output drive state, and blacked for the duration
of the desaturation blanking interval.
In FULLON mode, this signal is blanked and cannot generate an error.
MASK1:1
Framing Error–if a framing error occurs, an interrupt is generated.
MASK1:2
Write Error after locking.
MASK1:3
Reset Event–If the IC is reset or disabled, an interrupt occurs. Since the IC will always start from a reset condition, this can
be used to test the interrupt mechanism because when the IC comes out of RESET, an interrupt will immediately occur.
MODE COMMAND
This command is sent by sending binary 010x xxxx data.
Table 13. MODE Command
SPI Data Bits
7
6
5
4
3
2
1
0
Write
0
1
0
0
Desaturation
Fault Mode
0
FULLON
Mode
Mode
Lock
0
0
0
0
Reset
• Bit 0–Mode Lock is used to enable or disable Mode Lock. This bit can only be cleared with a device reset. Since the mode
Lock mode can only be set, this bit prevents any subsequent, and likely erroneous, mode, deadtime, or mask register
changes from being received. If an attempt is made to write to a register when Mode Lock is enabled, a Write Error fault
is generated.
• Bit 1–FULLON Mode. If this bit is set, programmed deadtime control is disabled, making it is possible to have both high
and Low Side drivers in a phase on simultaneously. This could be useful in special applications such as alternator
regulators, or switched-reluctance motor drive applications. There is no deadtime control in FULLON mode. Input signals
directly control the output stages, synchronized with the internal clock.
This bit is a “0”, after RESET. Until overwritten, the IC operates normally; deadtime control and logic prevents both outputs
from being turned on simultaneously.
• Bit 3– Desaturation Fault Mode controls what happen when a desaturation event is detected. When set to “0”, any
desaturation on any channel causes all six output drivers to shutoff. The drivers can only be re-enabled by executing the
CLINT command. When 1, desaturation faults are completely ignored.
Bit 3 controls behavior if a Desaturation, or Phase Error event is detected. The possibilities are:
— 0: Default: When a Desaturation, or Phase Error event is detected on any channel, all channels turn off and generates
an Interrupt, if interrupts are enabled.
— 1: Disable: Desaturation /Phase Error channel shutdown is disabled, but interrupts are still possible if unmasked.
Sending a MODE command and setting the Mode Lock simultaneously are allowed. This sets the requested mode and locks out any further
changes.
34937A
34
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
DEADTIME COMMAND
the deadtime register. Until the next deadtime calibration is
performed, 30 clock cycles will separate the turn off and turn
on gate signals in the same phase. The worst case error
immediately after calibration will be +0/-1 time base cycle, for
this example +0 ns/-50 ns. Note that if the internal time base
drifts, the effect on dead time will scale directly.
Sending a ZERO DEADTIME command (100x xxx0) sets
the deadtime timer to 0. However, simultaneous turn-on of
High Side and Low Side FETs in the same phase is still
prevented unless the FULLON command has been
transmitted. There is no calibration pulse expected after
receiving the ZERO DEADTIME command.
After RESET, deadtime is set to the maximum value of 255
time base cycles (typically 15 µs).
The IC ignores any SPI data that is sent during the
calibration pulse. If there are any transitions on SI or SCLK
while the Deadtime CS pulse is low, a Framing Error will be
generated, however, the CS pulse will be used to calibrate
the deadtime
Deadtime prevents the turn-on of both transistors in the
same phase until the deadtime has expired. The deadtime
timer starts when a FET is commanded off (see Figure 6 and
Figure 13). The deadtime control is disabled by enabling the
FULLON mode.
The deadtime is set by sending the DEADTIME command
(100x xxx1), and then sending a calibration pulse of CS. This
pulse must be 16 times longer than the required deadtime
(see Figure 19). Deadtime is measured in cycle times of the
internal time base, fTB. This measurement is divided by 16
and stored in an internal register to provide the reference for
timing the deadtime between high and low gate transactions
in the same phase.
For example: the internal time base is running at 20 MHz
and a 1.5 µs deadtime is required. First a DEADTIME
command is sent (using the SPI), then a CS is sent. The CS
pulse is 16*1.5 = 24 µs wide. The IC measures this pulse as
24000 ns/50 ns = 480 clock cycles and stores 480/16 = 30 in
Table 14. .DEADTIME Command
SPI Data Bits
7
6
5
4
3
2
1
0
Write
1
0
0
x
x
x
x
ZERO/
CALIBRATE
x
x
x
x
Reset
Deadtime
Pulse
DeadtimeCalibration
Calibration
Pulse
CS
CS
SCLK
SCLK
SI
SI
Deadtime
DEADTIME
Command
Command
SO
SO
Figure 19. Deadtime Calibration
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
35
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
STATUS REGISTERS
Other commands return a general status word in the Status
Register 0.
There are four Status Registers in the IC. Status
Register 0 is most commonly used for general status.
Registers one through three are used to read or confirm
internal IC settings.
After any SPI command, the status of the IC is reported in
the return value from the SPI port. There are four variants of
the NULL command used to read various status in the IC.
Status Register 0 (Status Latch Bits)
This register is read by sending the NULL0 command (000x xx00). It is also returned after any other command. This command
returns the following data:
Table 15. Status Register 0
SPI Data Bits
Results
Register 0
7
6
5
4
3
2
1
0
RESET
Write
Error
Framing
Error
Phase
Error
Overcurrent
Event
Low
VLS
DESAT
Detected on
any Channel
TLIM
Detected on
any Channel
1
0
0
0
0
0
0
0
Read
Reset
All status bits are latched. The latches are cleared only by sending a CLINT0 or CLINT1 command with the appropriate bits
set. If the status is still present, that bit will not clear. CLINT0 and CLINT1 have the same format as MASK0 and MASK1
respectively.
• Bit 0–is a flag for Overtemperature on any channel. This bit is the OR of the latched three internal TLIM detectors.This
flag can generate an interrupt if the appropriate mask bit is set.
• Bit 1–is a flag for Desaturation Detection on any channel. This bit is the OR of the latched three internal High Side
desaturation detectors and phase error logic. Faults are also detected on the Low Side as phase errors. A phase error is
generated if the output signal (at Px_HS_S) does not properly reflect the drive conditions. The phase error is the triple OR
of phase errors from each phase. Each phase error is the OR of the HS and LS phase errors. An HS phase error (which
will also trigger the desaturation detector) occurs when the HS FET is commanded on, and the Px_HS_S is still low in the
deadtime duration after it is driven ON. Similarly, a LS phase error occurs when the LS FET is commanded on, and the
Px_HS_S is still high in the deadtime duration after the FET is driven ON. This flag can generate an interrupt if the
appropriate mask bit is set.
• Bit 2– is a flag for Low Supply Voltage. This flag can generate an interrupt if the appropriate mask bit is set.
• Bit 3–is a flag for the output of the Overcurrent Comparator. This flag can generate an interrupt if the appropriate mask
bit is set.
• Bit 4–is a flag for a Phase Error. If any Phase comparator output is not at the expected value when just one of the
individual high or Low Side outputs is enabled, the fault flag is set. This signal is the XOR of the phase comparator output
with the output driver state, and blanked for the duration of the desaturation blanking interval. This flag can generate an
interrupt if the appropriate mask bit is set.
• Bit 5–is a flag for a Framing Error. A framing error is a SPI message not containing one or more multiples of eight bits.
SCLK toggling while measuring the Deadtime calibration pulse is also a framing error. This would typically be a transient
or permanent hardware error, perhaps due to noise on the SPI lines. This flag can generate an interrupt if the appropriate
mask bit is set.
• Bit 6–indicates a Write Error After the Lock bit is set. A write error is any attempted write to the MASKn, Mode, or a
Deadtime command after the Mode Lock bit is set. A write error is any attempt to write any other command than the one
defined in the Table 8. This would typically be a software error. This flag can generate an interrupt if the appropriate mask
bit is set.
• Bit 7–is set upon exiting RST. It can be used to test the interrupt mechanism or to flag for a condition where the IC gets
reset without the host being otherwise aware. This flag can generate an interrupt if the appropriate mask bit is set.
34937A
36
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Status Register 1 (MODE Bits)
This register is read by sending the NULL1 command (000x xx01). This is guaranteed to not affect IC operation and returns
the following data:
Table 16. Status Register 1
SPI Data Bits
7
6
5
4
3
2
1
0
Results
Register 1
0
Desaturation
Mode
Zero
Deadtime
Set
Calibration
Overflow
Deadtime
Calibration
0
FULLON
Mode
Lock
Bit
0
0
0
0
0
0
0
0
Read
Reset
• Bit 0–Lock Bit indicates the IC registers (Deadtime, MASKn, CLINTn, and Mode) are locked. Any subsequent write to
these registers is ignored and will set the Write Error flag.
• Bit 1– is the present status of FULLON Mode. If this bit is set to “0”, the FULLON mode is not allowed. A “1” indicates the
IC can operate in FULLON Mode (both High Side and Low Side FETs of one phase can be simultaneously turned on).
• Bit 3–indicates Deadtime Calibration occurred. It will be “0” until a successful Deadtime command is executed. This
includes the Zero Deadtime setting, as well as a Calibration Overflow.
• Bit 4–is a flag for a Deadtime Calibration Overflow.
• Bit 5–is set if Zero Deadtime is commanded.
• Bit 6–reflects the current state of the Desaturation/Phase Error turn-off mode.
Status Register 2 (MASK bits)
This register is read by sending the NULL2 command (000x xx10). This is guaranteed to not affect IC operation and returns
the following data:
Table 17. Status Register 2
SPI Data Bits
Results
Register 2
7
6
5
4
3
2
1
0
Mask1:3
Mask1:2
Mask1:1
Mask1:0
Mask0:3
Mask0:2
Mask0:1
Mask0:0
1
1
1
1
1
1
1
1
Read
Reset
Status Register 3 (Deadtime)
This register is read by sending the NULL3 command (000x xx11). This is guaranteed to not affect IC operation and returns
the following data:
Table 18. Status Register 3
SPI Data Bits
Results
Register 3
7
6
5
4
3
2
1
0
Dead7
Dead6
Dead5
Dead4
Dead3
Dead2
Dead1
Dead0
0
0
0
0
0
0
0
0
Read
Reset
These bits represent the calibration applied to the internal oscillator to generate the requested deadtime. If calibration is not
yet performed, all these bits return 0 even though the actual dead time is the maximum.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
37
FUNCTIONAL DEVICE OPERATION
INITIALIZATION REQUIREMENTS
INITIALIZATION REQUIREMENTS
The 34937A provides safe, dependable gate control for 3
phase BLDC motor control units when it is properly
configured. However, if improperly initialized, the high side
gate drive can be left in a high-impedance mode which will
allow charge to accumulate from external sources, eventually
turning on the high side output transistor. It is prudent to
follow a well defined initialization procedure which will
establish known states on the gates of all the phase drivers
before any current flows in the motor.
RECOVERY FROM SLEEP MODE (RESET)
The output gate drive is pulled low with the hold off circuit
as long as VLS is low, there is a Power On Reset condition or
+5V is low. These conditions are present during a Reset
condition. When first coming out of a reset condition, the gate
drive circuits are in a high-impedance state until the first
command is given for operation. After the Reset line goes
high, the supplies begin to operate and the hold off circuit is
deactivated. The phase input lines will not have any effect on
the gate drive until both ENABLE1 and ENABLE2 go high
and even then, the low side gate must be commanded on
before the high side gate can be operated. This is to insure
the bootstrap capacitor has been charged before
commencing normal operation. Then the high side gate must
be commanded on and then off to initialize the output latches.
A proper initialization sequence will place the output gate
drives in a low-impedance known condition prior to releasing
the device for normal operation.
A valid initialization sequence would go something like
this:
1. RESET goes high (ENABLE1 and ENABLE2 remain
low)
2. SPI commands to configure valid interrupts, DESAT
mode and Dead Time are issued
3. SPI command to clear all interrupt conditions
4. ENABLE1 and ENABLE2 are set HIGH (LS outputs are
now enabled)
5. PA_LS, PB_LS and PC_LS are toggled HIGH for about
1us (HS outputs are enabled, but not latched)
6. Toggle nPA_HS, nPB_HS and nPC_HS LOW for
DEAD TIME plus at least 0.1us (HS outputs are now
latched and operational).
End of initialization.
Doing step 6 simultaneously on all HS inputs will place the
motor into High Side Recirculation mode and will not cause
motion during the time they are ON.
This action will force the High Side gate drive out of tristate mode and leave it with the HS_G shorted to HS_S on
all phases. The HS output FETs will be OFF and ready for
normal motor control.
Step 5 and step 6 can be done on all the stated inputs
simultaneously. It may be desirable for the HS (step 6) to be
toggled simultaneously to prevent current from flowing in the
motor during initialization.
Note the inputs PA_LS, PB_LS, PC_LS, nPA_HS,
nPB_HS and nPC_HS are edge sensitive. Toggling the LS
inputs enables the HS drivers, so for the HS drivers to be
initialized correctly the edge of the input signal to the HS
drivers must come after the LS input toggle. A failure to do
this will result in the HS gate output remaining in a highimpedance mode. This can result in an accumulation of
charge, from internal and external leakage sources, on the
gate of the HS output FET causing it to turn ON even though
the input level to the 34937A would appear to indicate it
should be OFF. When this happens, the logic of the 34937A
will allow the LS output FET to be turned ON without taking
any action on the HS gate because the logic is still indicating
that the HS gate is OFF. The initial LS input transition from
low to high needs to be after both ENABLE inputs are high
(the device in NORMAL mode) for the same reason. The
delay between ENABLE and the LS input should be 280 ns
minimum to insure the device is out of STBY mode. Once
initialized the output gate drives will continue to operate in a
low-impedance mode as commanded by the inputs until the
next reset event.
34937A
38
Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
INITIALIZATION REQUIREMENTS
INT
SPI
CS
Px_HS
Px_LS
EN1-2
RST
VDD
VLS
VPWR
VSUP
tPU_VDD
tPU_VLS
t1
t2
t3
t4
t5
t6
Figure 20. Full Initialization
Table 19. Full Initialization Timing Description
Time
Description
Min
Comments
tPU_VDD,
tPU_VLS
Power up time from RESET
2.0 ms
RESET must remain high long enough for VDD and VLS to reach the full regulated
voltage. The normal time for this to occur is specified as 2.0 ms maximum. If there is
more capacitance on VLS or VDD than the normal values given in the specification, this
time may need to be increased. In general, the time may be safely scaled linearly with
the capacitance. If the charge pump is used it may also increase this time. An estimate
of increased time, due to the charge pump, would be to add 25%. For example, the
nominal VLS capacitance is 2.2 µF on each pin, the power up time should be increased
to 4.0 ms, 5.0 ms if using the charge pump.
t1
End of SPI communication to
EN1 and EN2 rising edge
0 ns
t2
EN1 and EN2 rising edge to
first LS output command
280 ns
Restricted by EN1 and EN2 propagation delay
t3
Initial LS ON period
1.0 µs
Nominally 1.0 µs is more that enough. The calculated value is 5*Cboot(RSENSE +
RDSON_LS). 100 ns for default recovery.
t4
LS OF to HS ON
0 ns
No defined maximum, but HS is undefined until beginning of toggle on the HS
t5
Initial HS ON period
100 ns + Minimum: Dead-time + 100 ns to guarantee the HS is switched.
dead
Maximum: Same limitations as Normal Operation. Unlimited time if leakage currents
time
are less than trickle charge pump margin.
t6
HS OFF to Normal Operation
0 ns
Immediately begin Normal Operation
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
39
FUNCTIONAL DEVICE OPERATION
INITIALIZATION REQUIREMENTS
RECOVERY FROM STANDBY MODE OR A FAULT
When the 34937A is placed in Standby Mode or a fault
condition causes a shutdown, the Gate outputs are all driven
low. The High Side gate drive is then disabled and locked to
prevent unauthorized transitions. This requires an
initialization sequence to recover normal operation at the end
of this mode of operation. The initialization sequence is
nearly identical to recovery from Sleep mode, with the
modification that the initial pulse to the Low Side Control
inputs can be reduced to a 100 ns pulse (the Low Side Gates
may not actually change state). Then the initialization is
completed by cycling the High Side Gates to re-engage the
gate drive and insure that it is in the proper state prior to
resuming normal operation.
A valid initialization sequence would go something like
this:
1. SPI command to clear all interrupt conditions
2. ENABLE1 and ENABLE2 are set HIGH (LS outputs are
now enabled)
3. PA_LS, PB_LS and PC_LS are toggled HIGH for at
least 100 ns (HS Gate Drive outputs are enabled)
longer if bootstrap capacitors need charged.
4. Toggle nPA_HS, nPB_HS and nPC_HS LOW for
DEAD TIME plus at least 100 ns.
End of initialization.
Doing step 4 simultaneously on all HS inputs will place the
motor into HIGH Side Recirculation mode and will not cause
motion during the time they are ON.
This action will restore the High Side gate drive operation
and leave it with the HS_G shorted to HS_S on all phases.
The HS output FETs will be OFF and ready for normal motor
control.
Step 3 and step 4 can be done on all the stated inputs
simultaneously. In fact it is desirable for the HS (step 4) to be
toggled simultaneously to prevent current from flowing in the
motor during initialization.
Note the inputs PA_LS, PB_LS, PC_LS, nPA_HS,
nPB_HS and nPC_HS are edge sensitive. Toggling the LS
inputs enables the HS drivers, so for the HS drivers to be
initialized correctly the edge of the input signal to the HS
drivers must come after the LS input toggle. A failure to do
this will result in the HS gate output remaining locked out from
input control. The initial LS input transition from low to high
needs to be after both ENABLE inputs are high (the device in
NORMAL mode) for the same reason. The delay between
ENABLE and the LS input should be 280 ns minimum to
insure the device is out of STBY mode.
INT
SPI
nCS
Px_Combined
nPx_HS
Clear
0.1µs
0.1µs
Px_LS
EN2
EN1
Figure 21. Recovery Initialization
The horizontal divisions are not to scale, they are a
reference to show the sequence of operation. Either
individual nPx_HS and Px_LS or nPx_Combined may be
used. nPx_Combined is defined as both nPx_HS and Px_LS
tied together or operated to the same logic level
simultaneously.
34937A
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Analog Integrated Circuit Device Data
Freescale Semiconductor
FUNCTIONAL DEVICE OPERATION
INITIALIZATION REQUIREMENTS
IC INITIALIZATION
This process flow will initialize the IC and its software environment.
1. Apply power (VSYS) to module
2. Remove RST (RST goes high, EN1 and EN2 are still low)
2.1. When RST rises above the threshold, the device will power-up. The charge pump (if configured) will start, allow VDD
and VLS to stabilize.
3. Initialize registers
3.1. Clear all interrupt status flags (send CINT0 and CINT1)
3.2. Initialize MASK register by sending 0010 xxxx or 0011 xxxx to mask out unwanted interrupts.
3.3. Set desired dead time either by commanding zero dead time or calibrating the dead time.
3.4. Send MODE command with desired bits, and also the Lock bit. e.g. 01000001. This prevents further mode changes.
4. Bring EN1 & EN2 high
5. Initialize the outputs
5.1. Command all Px_HS to logic 1 (High Side OFF)
5.2. Command all Px_LS to logic 1 (commanding Low Side ON). The input must transition from low to high after EN1 and
EN2 have gone high.
5.3. Wait for the bootstrap capacitors to charge (about 1us typically)
5.4. Command all Px_LS to logic 0 (command Low Side OFF)
5.5. Command all Px_HS to logic 0 (command High Side ON)
5.6. Command all Px_HS to logic 1 (command High Side OFF)
The device is now ready for normal operation.
INTERRUPT HANDLER
When an interrupt occurs, the general procedure is to send NULL0 and NULL1 commands to determine what happened, take
corrective action (if needed), clear the fault and return.
Because the return value from an SPI command is actually returned in the subsequent message, main-loop software that tries
to read SR1, SR2 or SR3, may experience an interrupt between sending the SPI command and the subsequent read. Thus if
these registers are to be read, special care must be taken in the software to ensure that the correct results are being interpreted.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
41
TYPICAL APPLICATIONS
TYPICAL APPLICATIONS
VSYS
+12V Nom.
D1
C2
C1
PUMP
VPUMP
VPWR
VSUP
Main
Charge
Pump
PGND
To Other
Two Phases
C6
D2
Trickle
Charge
Pump
5V
Reg.
VDD
Hold
-Off
Circuit
VLS
Reg.
VLS
Oscillator
C3
VDD
UV
Detect
3x
Px_BOOT
T-Lim
RST
INT
EN1
EN2
Px_HS
Px_LS
VSUP
3
Control
3
Logic
Desat.
Comp.
+
-
High
-Side
Driver
(Optional)
To Motor
Px_HS_S
QLS
Phase VSUP
Comp.
3
Low
-Side
OC_OUT
Over-Cur.
Comp.
OC_TH
+
-
To ADC
Px_HS_G
QHS
Phase x
Output
Driver
GND
Cx_Boot
Rg_HS
1.4V
CS
SI
SCLK
SO
PHASE_x
C4
Px_LS_G
(Optional)
Phase
Return
Px_LS_S
I-sense
Amp.
AMP_OUT
AMP_N
Rg_LS
R1
AMP_P
VLS_CAP
C5
R3
R2
RSense
+
-
Rfb
Figure 22. Typical Application Diagram Using Charge Pump
34937A
42
Analog Integrated Circuit Device Data
Freescale Semiconductor
TYPICAL APPLICATIONS
VSYS
+42V Nom.
To Other
Two Phases
C6
+14V Nom.
C2
PUMP
VPUMP
VPWR
VSUP
Main
Charge
Pump
PGND
Trickle
Charge
Pump
5V
Reg.
VDD
Hold
-Off
Circuit
VLS
Reg.
VLS
Oscillator
C3
VDD
UV
Detect
3x
T-Lim
RST
INT
EN1
EN2
Px_HS
Px_LS
VSUP
3
Control
3
Logic
Desat.
Comp.
+
-
Px_BOOT
High
-Side
Driver
Px_HS_G
QHS
(Optional)
Phase x
Output
To Motor
Px_HS_S
QLS
Phase VSUP
Comp.
3
Low
-Side
Driver
OC_OUT
GND
Cx_Boot
Rg_HS
1.4V
CS
SI
SCLK
SO
PHASE_x
C4
Over-Cur.
Comp.
OC_TH
+
-
Px_LS_G
(Optional)
Phase
Return
Px_LS_S
I-sense
Amp.
AMP_OUT
AMP_N
Rg_LS
R1
AMP_P
VLS_CAP
C5
R3
R2
RSense
+
-
Rfb
To ADC
Figure 23. High-voltage Application Diagram (+42 V System)
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
43
TYPICAL APPLICATIONS
1
0.9
Power Dissipated (W)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
5
10
15
20
25
30
35
40
Supply Voltage (V)
Figure 24. Power Dissipation Profile of Application Using Charge Pump
Reference application with:
• Pump capacitor: 1.0 F MLC
• Pump filter capacitor: 47 F low ESR aluminum electrolytic
• Pump diodes: MUR120
• Output FET gate charge: 240 nC @ 10 V
• PWM Frequency: 20 kHz
• Switching Single Phase
Below approximately 17 V the charge pump is actively regulating VPWR. The increased power dissipation is due to the charge
pump losses. Above this voltage the charge pump oscillator shuts down and VSYS is passed through the pump diodes directly to
VPWR.
34937A
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Analog Integrated Circuit Device Data
Freescale Semiconductor
TYPICAL APPLICATIONS
1.500
1.400
1.300
1.200
Power Dissipation (W)
1.100
1.000
0.900
0.800
0.700
0.600
0.500
0.400
0.300
0.200
0.100
0.000
10
15
20
25
30
35
40
45
50
55
60
Supply Voltage (V)
Figure 25. Power Dissipation Profile of Application Not Using Charge Pump
Reference application with:
• Output FET gate charge: 240 nC @ 10 V
• PWM Frequency: 20 kHz
• Switching Single Phase
• No connections to PUMP or VPUMP
• VPWR connected to VSYS
If VPWR is supplied by a separate pre-regulator, the power dissipation profile will be nearly flat at the value of the pre-regulator
voltage for all VSYS voltages.
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
45
PACKAGING
PACKAGING DIMENSION
PACKAGING
PACKAGING DIMENSION
For the most current package revision, visit www.freescale.com and perform a keyword search using the “98ASA99334D” listed below.
Dimensions shown are provided for reference ONLY..
EK SUFFIX (PB-FREE)
54-PIN
98ASA99334D
ISSUE C
34937A
46
Analog Integrated Circuit Device Data
Freescale Semiconductor
PACKAGING
PACKAGING DIMENSION (CONTINUED)
PACKAGING DIMENSION (CONTINUED)
EK SUFFIX (PB-FREE)
54-PIN
98ASA99334D
ISSUE C
34937A
Analog Integrated Circuit Device Data
Freescale Semiconductor
47
REVISION HISTORY
REVISION HISTORY
REVISION
DATE
DESCRIPTION OF CHANGES
1.0
7/2013
•
Initial Release based on the 33937A data sheet
2.0
9/2013
•
Added note to Operating Junction Temperature (7)
34937A
48
Analog Integrated Circuit Device Data
Freescale Semiconductor
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© 2013 Freescale Semiconductor, Inc.
Document Number: MC34937
Rev. 2.0
9/2013