ON NCV7517B Hex low-side mosfet pre-driver Datasheet

NCV7517B
FLEXMOSt Hex Low-Side
MOSFET Pre-Driver
The NCV7517B programmable six channel low−side MOSFET
pre−driver is one of a family of FLEXMOSTM automotive grade
products for driving logic−level MOSFETs. The product is
controllable by a combination of serial SPI and parallel inputs. It
features programmable fault management modes and allows
power−limiting PWM operation with programmable refresh time.
The device offers 3.3 V/5.0 V compatible inputs and the serial output
driver can be powered from either 3.3 V or 5.0 V. Power−on reset
provides controlled powerup and two enable inputs allow all outputs
to be simultaneously disabled.
Each channel independently monitors its external MOSFET’s
drain voltage for fault conditions. Shorted load fault detection
thresholds are fully programmable using an externally programmed
reference voltage and a combination of four discrete internal ratio
values. The ratio values are SPI selectable and allow different
detection thresholds for each group of three output channels.
Fault information for each channel is 2−bit encoded by fault type
and is available through SPI communication. Fault recovery
operation for each channel is programmable and may be selected for
latch−off or automatic retry.
The FLEXMOS family of products offers application scalability
through choice of external MOSFETs.
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MARKING
DIAGRAM
LQFP32
FT SUFFIX
CASE 561AB
A
WL
YY
WW
G
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
ORDERING INFORMATION
Device
Package
Shipping†
NCV7517BFTG
LQFP
(Pb−Free)
250 Units/Tray
NCV7517BFTR2G
LQFP
2000 Tape & Reel
(Pb−Free)
Features
•
•
•
•
•
•
•
•
•
16−Bit SPI with Frame Error Detection
3.3 V/5.0 V Compatible Parallel and Serial Control Inputs
3.3 V/5.0 V Compatible Serial Output Driver
Two Enable Inputs
Open−Drain Fault and Status Flags
Programmable
− Shorted Load Fault Detection Thresholds
− Fault Recovery Mode
− Fault Retry Timer
− Flag Masking
Load Diagnostics with Latched Unique Fault Type Data
− Shorted Load
− Open Load
− Short to GND
NCV Prefix for Automotive and Other Applications Requiring
Unique Site and Control Change Requirements; AEC−Q100
Qualified and PPAP Capable
These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
NCV7517B
AWLYYWWG
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
Benefits
• Scalable to Load by Choice of External MOSFET
© Semiconductor Components Industries, LLC, 2016
June, 2016 − Rev. 2
1
Publication Order Number:
NCV7517B/D
NCV7517B
IN5 IN4 IN3 IN2 IN1 IN0
ENA2
VCC2
NCV7517B
CHANNEL 0
Hex MOSFET Pre−Driver
DRN0
FAULT
DETECT
POWER ON RESET
&
BIAS
VCC1
VSS
POR
VCC2
DRIVER
ENA1
GATE SELECT
GAT0
VSS
FLAG MASK
ENA ENA VCC2
DRN
1
2
REF
DISABLE
DISABLE MODE
REFRESH/REF
CSB
PARALLEL
SERIAL
IREF
6
ENA ENA VCC2
DRN
1
2
REF
DISABLE
PARALLEL
SERIAL
VCC
SCLK
POR
CSB
SCLK
SI
CHANNEL 1
CHANNEL 2
IREF
SI
VSS
VSS
DRN1
GAT1
DRN2
GAT2
SPI
ENA ENA VCC2
DRN
1
2
REF
DISABLE
16 BIT
VDD
CHANNEL 3
PARALLEL
SERIAL
SO
DRIVER
IREF
SO
DRN
VSS
ENA ENA VCC2
1
2
REF
DISABLE
PARALLEL
SERIAL
12
FAULT BITS
2
GND
+
OA
−
ENA ENA VCC2
DRN
1
2
REF
DISABLE
FAULT LOGIC
&
REFRESH TIMER
ENA1
4
FLTREF
CHANNEL 4
IREF
FLTB
VSS
CHANNEL 5
PARALLEL
SERIAL
IREF
CLOCK
FAULT
REFERENCE
GENERATOR
VSS
DRN 0:5
CH
0−2
MASK 0:5
CH
3−5
POR
Figure 1. Block Diagram
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2
ENA
1
VSS
DRN3
GAT3
DRN4
GAT4
DRN5
GAT5
VSS
DRAIN
FEEDBACK
MONITOR
STAB
M
+5V
14W
UNCLAMPED LOAD
VLOAD
14W
28W
28W
5W
NCV7517B
RFILT
CB1
+5V OR
+3.3V
RX1
POWER−ON
RESET
VCC1
VCC2
FLTREF
DRN0
ENA1
GAT0
ENA2
DRN1
IN0
GAT1
IN1
DRN2
RD0
NID9N05CL
RD1
NID9N05CL
RD2
IN2
SPI
IN3
IN4
IN5
NID9N05CL
NCV7517B
HOST CONTROLLER
PARALLEL
RX2
RST
GAT2
RD3
CB2
DRN3
NID9N05CL
GAT3
RD4
DRN4
NID9N05CL
IRQ
FLTB
GAT4
I/O
CSB
DRN5
SCLK
GAT5
RD5
NID9N05CL
RFPU
SI
VDD
STAB
SO
GND
VSS
RSPU
Figure 2. Application Diagram
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3
NCV7517B
PIN FUNCTION DESCRIPTION
Symbol
FLTREF
Description
Analog Fault Detect Threshold: 5.0 V Compliant
DRN0 – DRN5
Analog Drain Feedback: Internally Clamped
GAT0 – GAT5
Analog Gate Drive: 5.0 V Compliant
ENA1, ENA2
Digital Master Enable Inputs: 3.3 V/5.0 V (TTL) Compatible
Digital Parallel Input: 3.3 V/5.0 V (TTL) Compatible
Digital Serial Data Output: 3.3 V/5.0 V Compliant
STAB
Digital Open−Drain Output: 3.3 V/5.0 V Compliant
FLTB
Digital Open−Drain Output: 3.3 V/5.0 V Compliant
VCC1
Power Supply − Low Power Path
GND
Power Return − Low Power Path – Device Substrate
VCC2
Power Supply − Gate Drivers
VDD
Power Supply − Serial Output Driver
VSS
Power Return – VCC2, VDD, Drain Clamps
DRN5
SO
GAT4
Digital Serial Data Input: 3.3 V/5.0 V (TTL) Compatible
DRN4
SI
GAT3
Digital Shift Clock Input: 3.3 V/5.0 V (TTL) Compatible
DRN3
SCLK
GAT2
Digital Chip Select Input: 3.3 V/5.0 V (TTL) Compatible
DRN2
CSB
GAT5
IN0 – IN5
24 23 22 21 20 19 18 17
GAT1
25
16
VSS
DRN1
26
15
STAB
GAT0
27
14
VDD
DRN0
28
13
SO
VCC2
29
12
SI
VCC1
30
11
SCLK
FLTREF
31
10
CSB
GND
32
9
FLTB
4
5
6
7
8
IN4
IN5
ENA2
ENA1
IN1
3
IN3
2
IN2
1
IN0
NCV7517B
Figure 3. 32 Pin LQFP Pinout (Top View)
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4
NCV7517B
MAXIMUM RATINGS (Voltages are with respect to device substrate.)
Rating
Value
Unit
−0.3 to 6.5
V
Difference Between VCC1 and VCC2
"0.3
V
Difference Between GND (Substrate) and VSS
"0.3
V
Output Voltage (Any Output)
−0.3 to 6.5
V
Drain Feedback Clamp Voltage (Note 1)
−0.3 to 47
V
Drain Feedback Clamp Current (Note 1)
10
mA
Input Voltage (Any Input)
−0.3 to 6.5
V
Junction Temperature, TJ
−40 to 150
°C
Storage Temperature, TSTG
−65 to 150
°C
Peak Reflow Soldering Temperature: Lead−Free
60 to 150 seconds at 217°C (Note 2)
260 peak
°C
DC Supply (VCC1, VCC2, VDD)
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
ATTRIBUTES
Characteristic
Value
ESD Capability
Human Body Model
Machine Model
w " 2.0 kV
w " 200 V
Moisture Sensitivity (Note 2)
MSL2
Package Thermal Resistance (Note 3)
Junction–to–Ambient, RqJA
Junction–to–Pin, RYJL
86.0 °C/W
58.5 °C/W
1. An external series resistor must be connected between the MOSFET drain and the feedback input in the application. Total clamp power
dissipation is limited by the maximum junction temperature, the application environment temperature, and the package thermal resistances.
2. For additional information, see or download ON Semiconductor’s Soldering and Mounting Techniques Reference Manual, SOLDERRM/D, and
Application Note AND8003/D.
3. Values represent still air steady−state thermal performance on a 4 layer (42 x 42 x 1.5 mm) PCB with 1 oz. copper on an FR4 substrate, using
a minimum width signal trace pattern (384 mm2 trace area).
RECOMMENDED OPERATING CONDITIONS
Symbol
Parameter
Min
Max
Unit
4.75
5.25
V
VCC1 − 0.3
VCC1 + 0.3
V
VCC1
Main Power Supply Voltage
VCC2
Gate Drivers Power Supply Voltage
VDD
Serial Output Driver Power Supply Voltage
3.0
VCC1
V
VIN High
Logic High Input Voltage
2.0
VCC1
V
VIN Low
Logic Low Input Voltage
TA
Ambient Still−Air Operating Temperature
0
0.8
V
−40
125
°C
Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses beyond the
Recommended Operating Ranges limits may affect device reliability.
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5
NCV7517B
ELECTRICAL CHARACTERISTICS (4.75 VvVCCXv5.25 V, VDD = VCCX, −40°CvTJv125°C, unless otherwise specified.) (Note 4)
Characteristic
Symbol
Conditions
Min
Typ
Max
Unit
ENAX = 0
ENA1 = ENA2 = VCC1,
VDRNX = 0 V, GATX drivers off
ENA1 = ENA2 = VCC1,
GATX drivers on
–
–
2.80
3.10
5.0
5.0
mA
–
2.80
5.0
3.65
4.20
4.60
V
0.150
0.385
–
V
2.0
–
–
V
VCC1 Supply
Operating Current –
VCC1 = 5.25 V, VFLTREF = 1.0 V
Power−On Reset Threshold
VCC1 Rising
Power−On Reset Hysteresis
−
Digital I/O
VIN High
ENAX, INX, SI, SCLK, CSB
VIN Low
ENAX, INX, SI, SCLK, CSB
–
–
0.8
V
VIN Hysteresis
ENAX, INX, SI, SCLK, CSB
100
330
500
mV
Input Pullup Current
CSB VIN = 0 V
−25
−10
–
mA
Input Pulldown Current
ENA2, INX, SI, SCLK,
VIN = VCC1
–
10
25
mA
Input Pulldown Resistance
ENA1
SO Low Voltage
VDD = 3.3 V, ISINK = 5.0 mA
SO High Voltage
VDD = 3.3 V, ISOURCE = 5.0 mA
SO Output Resistance
Output High or Low
SO Tri−State Leakage Current
CSB = 3.3 V
STAB Low Voltage
STAB Leakage Current
100
150
200
kW
–
0.11
0.25
V
VDD −
0.25
VDD −
0.11
–
V
–
22
–
W
−10
–
10
mA
STAB Active, ISTAB = 1.25 mA
–
0.1
0.25
V
VSTAB = VCC1
–
–
10
mA
FLTB Low Voltage
FLTB Active, IFLTB = 1.25 mA
–
0.1
0.25
V
FLTB Leakage Current
VFLTB = VCC1
–
–
10
mA
FLTREF Input Current
VFLTREF = 0 V
−1.0
–
–
mA
FLTREF Input Linear Range
(Note 5)
0
–
VCC1 −
2.0
V
(Note 5)
30
–
–
dB
IDRNX = 10 mA
IDRNX = ICL(MAX) = 10 mA
27
–
34
42
–
47
V
Register 2: R1 = 0, R0 = 0 or
R4 = 0, R3 = 0
20
25
30
%
VFLTREF
Register 2: R1 = 0, R0 = 1 or
R4 = 0, R3 = 1
45
50
55
%
VFLTREF
Register 2: R1 = 1, R0 = 0 or
R4 = 1, R3 = 0
70
75
80
%
VFLTREF
Register 2: R1 = 1, R0 = 1 or
R4 = 1, R3 = 1
95
100
105
%
VFLTREF
VCC1 = VCC2 = VDD = 5.0 V,
ENAX = INX = 0 V,
VDRNX = VCL(MIN)
VCC1 = VCC2 = VDD = 0 V,
ENAX = INX = 0 V,
VDRNX = VCL(MIN)
−1.0
–
1.0
mA
Fault Detection – GATX ON
FLTREF Op−amp VCC1 PSRR
DRNX Clamp Voltage
DRNX Shorted Load Threshold
GATX Output High
VFLTREF = 1.0 V
DRNX Input Leakage Current
VCL
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
4. Designed to meet these characteristics over the stated voltage and temperature recommended operating ranges, though may not be 100%
parametrically tested in production.
5. Guaranteed by design.
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6
NCV7517B
ELECTRICAL CHARACTERISTICS (continued) (4.75 VvVCCXv5.25 V, VDD = VCCX, −40°CvTJv125°C, unless otherwise
specified.) (Note 6)
Characteristic
Symbol
Conditions
Min
Typ
Max
Unit
Fault Detection – GATX OFF
DRNX Diagnostic Current
DRNX Fault Threshold Voltage
DRNX Off State Bias Voltage
ISG
Short to GND Detection,
VDRNX = 0.30 VCC1
−27
−20
−10
mA
IOL
Open Load Detection,
VDRNX = 0.75 VCC1
30
60
80
mA
VSG
Short to GND Detection
27
30
33
%VCC1
VOL
Open Load Detection
72
75
78
%VCC1
–
50
–
%VCC1
200
350
500
W
−26.25
–
−9.5
mA
9.5
–
26.25
mA
–
–
1.0
–
–
1.0
–
–
277
ns
–
–
277
ns
VCTR
−
Gate Driver Outputs
GATX Output Resistance
Output High or Low
GATX High Output Current
VGATX = 0 V
GATX Low Output Current
VGATX = VCC2
Turn−On Propagation Delay
tP(ON)
ms
INX to GATX (Figure 4)
CSB to GATX (Figure 5)
Turn−Off Propagation Delay
tP(OFF)
ms
INX to GATX (Figure 4)
CSB to GATX (Figure 5)
Output Rise Time
tR
20% to 80% of VCC2,
CLOAD = 400 pF
(Figure 4, Note 5)
Output Fall Time
tF
80% to 20% of VCC2,
CLOAD = 400 pF
(Figure 4, Note 5)
Fault Timers
Channel Fault Blanking Timer
tBL(ON)
VDRNX = 5.0 V; INX rising to
FLTB falling (Figure 6)
11
21
31
ms
tBL(OFF)
VDRNX = 0 V; INX falling to
FLTB falling (Figure 6)
90
120
150
ms
Channel Fault Filter Timer
tFF
Figure 7
7.0
12
17
ms
Global Fault Refresh Timer
(Auto−retry Mode)
tFR
Register 2: Bit R2 = 0 or R5 = 0
7.5
10
12.5
ms
Register 2: Bit R2 = 1 or R5 = 1
30
40
50
ms
ENA1 = 1
–
500
–
kHz
3.0
3.3
3.6
V
4.5
5.0
5.5
V
–
250
–
ns
Timer Clock
Serial Peripheral Interface (Figure 9) Vccx = 5.0 V, VDD = 3.3 V, FSCLK = 4.0 MHz, CLOAD = 200 pF
SO Supply Voltage
VDD
3.3 V Interface
5.0 V Interface
SCLK Clock Period
−
Maximum Input Capacitance
Sl, SCLK (Note 7)
–
–
12
pF
SCLK High Time
SCLK = 2.0 V to 2.0 V
125
–
–
ns
SCLK Low Time
SCLK = 0.8 V to 0.8 V
125
–
–
ns
Sl Setup Time
Sl = 0.8 V/2.0 V to
SCLK = 2.0 V (Note 7)
25
–
–
ns
Sl Hold Time
SCLK = 2.0 V to
Sl = 0.8 V/2.0 V (Note 7)
25
–
–
ns
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
6. Designed to meet these characteristics over the stated voltage and temperature recommended operating ranges, though may not be 100%
parametrically tested in production.
7. Guaranteed by design.
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7
NCV7517B
ELECTRICAL CHARACTERISTICS (continued) (4.75 VvVCCXv5.25 V, VDD = VCCX, −40°CvTJv125°C, unless otherwise
specified.) (Note 8)
Characteristic
Symbol
Conditions
Min
Typ
Max
Unit
Serial Peripheral Interface (continued) (Figure 9) Vccx = 5.0 V, VDD = 3.3 V, FSCLK = 4.0 MHz, CLOAD = 200 pF
SO Rise Time
(20% VSO to 80% VDD)
CLOAD = 200 pF (Note 9)
–
25
50
ns
SO Fall Time
(80% VSO to 20% VDD)
CLOAD = 200 pF (Note 9)
–
–
50
ns
CSB Setup Time
CSB = 0.8 V to SCLK = 2.0 V
(Note 9)
60
–
–
ns
CSB Hold Time
SCLK = 0.8 V to CSB = 2.0 V
(Note 9)
75
–
–
ns
CSB to SO Time
CSB = 0.8 V to SO Data Valid
(Note 9)
–
65
125
ns
SO Delay Time
SCLK = 0.8 V to SO Data Valid
(Note 9)
–
65
125
ns
Transfer Delay Time
CSB Rising Edge to Next
Falling Edge (Note 9)
1.0
–
–
ms
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
8. Designed to meet these characteristics over the stated voltage and temperature recommended operating ranges, though may not be 100%
parametrically tested in production.
9. Guaranteed by design.
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8
NCV7517B
INX
50%
tP(OFF)
GAT X
tR
80%
50%
20%
tP(ON)
Figure 4. Gate Driver Timing Diagram – Parallel Input
CSB
50%
GX
tP(OFF)
GAT X
50%
tP(ON)
Figure 5. Gate Driver Timing Diagram – Serial Input
DRNX
INX
50%
tBL(ON)
FLTB
tBL(OFF)
50%
50%
Figure 6. Blanking Timing Diagram
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9
tF
NCV7517B
OPEN LOAD
THRESHOLD
SHORTED
LOAD
THRESHOLD
DRNX
INX
tFF
FLTB
tFF
50%
50%
Figure 7. Filter Timing Diagram
GAT X
tBL(ON)
tFR
tFF
DRNX
tFR
tBL(ON)
tFR
SHORTED LOAD THRESHOLD (FLTREF)
INX
Figure 8. Fault Refresh Timing Diagram
CSB
SETUP
TRANSFER
DELAY
CSB
SI
SETUP
SCLK
CSB
HOLD
1
16
SI
HOLD
SI
MSB IN
SO
DELAY
CSB to
SO VALID
SO
LSB IN
BITS 14...1
MSB OUT
SO
RISE,FALL
BITS 14...1
LSB OUT
SEE
NOTE
80% VDD
20% VDD
Note: Not defined but usually MSB of data just received.
Figure 9. SPI Timing Diagram
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10
NCV7517B
DETAILED OPERATING DESCRIPTION
General
The NCV7517B is a six channel general purpose
low−side pre−driver for controlling and protecting N−type
logic level MOSFETs. While specifically designed for
driving MOSFETs with resistive, inductive or lamp loads
in automotive applications, the device is also suitable for
industrial and commercial applications. Programmable
fault detection and protection modes allow the NCV7517B
to accommodate a wide range of external MOSFETs and
loads, providing the user with flexible application
solutions. Separate power supply pins are provided
for low and high current paths to improve analog
accuracy and digital signal integrity. ON Semiconductor’s
SMARTDISCRETES TM clamp MOSFETs, such as the
NID9N05CL, are recommended when driving unclamped
inductive loads.
The active−low CSB chip select input has a pullup
current source. The SI and SCLK inputs have pulldown
current sources. The recommended idle state for SCLK is
low. The tri−state SO line driver can be supplied with either
3.3 or 5.0 V and is powered via the device’s VDD and VSS
pins.
The NCV7517B employs frame error detection that
requires integer multiples of 16 SCLK cycles during each
CSB high−low−high cycle (valid communication frame.)
A frame error does not affect the flags. The CSB input
controls SPI data transfer and initializes the selected
device’s frame error and fault reporting logic.
The host initiates communication when a selected
device’s CSB pin goes low. Output (fault) data is
simultaneously sent MSB first from the SO pin while input
(command) data is received MSB first at the SI pin under
synchronous control of the master’s SCLK signal while
CSB is held low (Figure 10). Fault data changes on the
falling edge of SCLK and is guaranteed valid before the
next rising edge of SCLK. Command data received must be
valid before the rising edge of SCLK.
When CSB goes low, frame error detection is initialized,
latched fault data is transferred to the SPI, and the FLTB
flag is disabled and reset if previously set. Data for faults
detected while CSB is low are ignored but will be captured
if still present after CSB goes high.
If a valid frame has been received when CSB goes high,
the last multiple of 16 bits received is decoded into
command data, and FLTB is re−enabled. Latched
(previous) fault data is cleared and current fault data is
captured. The FLTB flag will be set if a fault is detected.
If a frame error is detected when CSB goes high, new
command data is ignored, and previous fault data remains
latched and available for retrieval during the next valid
frame. The FLTB flag will be set if a fault (not a frame
error) is detected.
Power Up/Down Control
The NCV7517B’s powerup/down control prevents
spurious output operation by monitoring the VCC1 power
supply. An internal Power−On Reset (POR) circuit causes
all GATX outputs to be held low until sufficient voltage is
available to allow proper control of the device. All internal
registers are initialized to their default states, fault data is
cleared, and the open−drain fault (FLTB) and status
(STAB) flags are disabled.
When VCC1 exceeds the POR threshold, outputs and
flags are enabled and the device is ready to accept input
data. When VCC1 falls below the POR threshold during
power down, flags are reset and disabled and all GATX
outputs are driven and held low until VCC1 falls below
about 0.7 V.
SPI Communication
The NCV7517B is a 16−bit SPI slave device. SPI
communication between the host and the NCV7517B may
either be parallel via individual CSB addressing or
daisy−chained through other devices using a compatible
SPI protocol.
CSB
MSB
SCLK
LSB
1
2
4 − 13
3
14
15
16
SI
X
B15
B14
B13
B12 − B3
B2
B1
B0
SO
Z
B15
B14
B13
B12 − B3
B2
B1
B0
Note: X=Don’t Care, Z=Tri−State, UKN=Unknown Data
Figure 10. SPI Communication Frame Format
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11
X
UKN
Z
NCV7517B
Serial Data and Register Structure
The 16−bit data sent by the NCV7517B is always the
encoded 12−bit fault information, with the upper 4 bits
forced to zero. The 16−bit data received is decoded into a
4−bit address and a 6−bit data word (see Figure 11). The
upper four bits, beginning with the received MSB, are fully
decoded to address one of four programmable registers and
the lower six bits are decoded into data for the addressed
register. Bit B15 must always be set to zero. The valid
register addresses are shown in Table 1. Each register is
next described in detail.
MSB
LSB
B15 B14 B13 B12 B11 B10
0
0
0
0
B9
CH5
B8
B7
CH4
B6
CH3
B5
B4
CH2
B3
B2
CH1
B1
B0
CH0
CHANNEL FAULT OUTPUT DATA
REGISTER SELECT
COMMAND INPUT DATA
MSB
LSB
B15 B14 B13 B12 B11 B10
0
A2
A1
A0
X
X
B9
B8
B7
B6
B5
B4
B3
B2
B1
B0
X
X
X
X
D5
D4
D3
D2
D1
D0
Figure 11. SPI Data Format
Table 1. Register Address Definitions
4−BIT ADDRESS
6−BIT INPUT DATA
B15
A2
A1
A0
D5
D4
D3
D2
0
0
0
0
Gate Select
0
0
0
1
Disable Mode
0
0
1
0
Refresh & Reference
0
0
1
1
Flag Mask
0
1
X
X
Null
D1
D0
16−BIT OUTPUT DATA
B15
B14
B13
B12
B11
0
0
0
0
D11
B0
12−bit Fault Data
Gate Select – Register 0
Each GATX output is turned on/off by programming its
respective GX bit (see Table 2). Setting a bit to 1 causes the
selected GATX output to drive its external MOSFET’s gate
to VCC2 (ON). Setting a bit to 0 causes the selected GATX
output to drive its external MOSFET’s gate to VSS (OFF).
Note that the actual state of the output depends on POR,
ENAX and shorted load fault states as later defined by
Equation 1. At powerup, each bit is set to 0 (all outputs
OFF).
to 1 causes the selected GATX output to latch−off when a
fault is detected. Setting a bit to 0 causes the selected GATX
output to auto−retry when a fault is detected. At powerup,
each bit is set to 0 (all outputs in auto−retry mode).
Table 3. Disable Mode Register
A1
A0
D5
D4
D3
D2
D1
D0
0
0
0
G5
G4
G3
G2
G1
G0
A2
A1
A0
D5
D4
D3
D2
D1
D0
0
0
1
M5
M4
M3
M2
M1
M0
0 = AUTO−RETRY
1 = LATCH OFF
Table 2. Gate Select Register
A2
D0
Refresh and Reference – Register 2
Refresh time (auto−retry mode) and shorted load fault
detection references are programmable in two groups of
three channels. Refresh time and the fault reference for
channels 5−3 is programmed by RX bits 5−3. Refresh time
and the fault reference for channels 2−0 is programmed by
RX bits 2−0 (see Table 4). At powerup, each bit is set to 0
(VFLT = 25% VFLTREF , tFR = 10 ms).
0 = GATX OFF
1 = GATX ON
Disable Mode – Register 1
The disable mode for shorted load faults is controlled by
each channel’s respective MX bit (see Table 3). Setting a bit
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12
NCV7517B
Table 4. Refresh and Reference Register
A2
A1
A0
D5
D4
D3
D2
D1
D0
0
1
0
R5
R4
R3
R2
R1
R0
CHANNELS 5−3
CHANNELS 2−0
25% VFLTREF
X
0
0
X
0
0
50% VFLTREF
X
0
1
X
0
1
75% VFLTREF
X
1
0
X
1
0
VFLTREF
X
1
1
X
1
1
tFR = 10 ms
X
X
X
0
X
X
tFR = 40 ms
X
X
X
1
X
X
tFR = 10 ms
0
X
X
X
X
X
tFR = 40 ms
1
X
X
X
X
X
Flag Mask – Register 3
The drain feedback from each channel’s DRNX input is
combined with the channel’s KX mask bit (Table 5). When
KX = 1, a channel’s mask is cleared and its feedback to the
FLTB and STAB flags is enabled. At powerup, each bit is
set to 0 (all masks set).
Gate Driver Control and Enable
Each GATX output may be turned on by either its
respective parallel INX input or the internal GX (Gate
Select) register bit via SPI communication. The device’s
common ENAX enable inputs can be used to implement
global control functions, such as system reset, overvoltage
or input override by a watchdog controller. Each parallel
input and the ENA2 input have individual internal
pulldown current sources. The ENA1 input has an internal
pulldown resistor. Unused parallel inputs should be
connected to GND and unused enable inputs should be
connected to VCC1. Parallel input is recommended when
low frequency (v2.0 kHz) PWM operation of the outputs
is desired.
ENA2 disables all GATX outputs when brought low.
When ENA1 is brought low, all GATX outputs, the timer
clock, and the flags are disabled. The fault and gate
registers are cleared and the flags are reset. New serial GX
data is ignored while ENA1 is low but other registers can
be programmed.
When both the ENA1 and ENA2 inputs are high, the
outputs will reflect the current parallel or serial input states.
This allows ENA1 to be used to perform a soft reset and
ENA2 to be used to disable the GATX outputs during
initialization of the NCV7517B.
The INX input state and the GX register bit data are
logically combined with the internal (active low)
power−on reset signal (POR), the ENAX input states, and
the shorted load state (SHRTX) to control the
corresponding GATX output such that:
Table 5. Flag Mask Register
A2
A1
A0
D5
D4
D3
D2
D1
D0
0
1
1
K5
K4
K3
K2
K1
K0
0 = MASK SET
1 = MASK CLEAR
The STAB flag is influenced when a mask bit changes
CLR→SET after one valid SPI frame. FLTB is influenced
after two valid SPI frames. This is correct behavior for
FLTB since, while a fault persists, the FLTB will be set
when CSB goes LO→HI at the end of an SPI frame. The
mask instruction is decoded after CSB goes LO→HI so
FLTB will only reflect the mask bit change after the next
SPI frame. Both FLTB and STAB require only one valid
SPI frame when a mask bit changes SET→CLR.
Null Register – Register 4
Fault information is always returned when any register
is addressed. The null register (Table 6) provides a way to
read back fault information without regard to the content
of DX.
Table 6. Null Register
A2
A1
A0
D5
D4
D3
D2
D1
D0
1
X
X
X
X
X
X
X
X
GATX + POR · ENA1 · ENA2 · SHRTx · (INx ) Gx)
(eq. 1)
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NCV7517B
The GATX state truth table is given in Table 7.
On−state faults will initiate MOSFET protection
behavior, set the FLTB flag and the respective channel’s DX
bits in the device’s fault latches. Off−state faults will
simply set the FLTB flag and the channel’s DX bits.
Fault types are uniquely encoded in a 2−bit per channel
format. Fault information for all channels simultaneously
is retrieved by SPI read (Figure 11). Table 8 shows the
fault−encoding scheme for channel 0. The remaining
channels are identically encoded.
Table 7. Gate Driver Truth Table
POR
ENA1
ENA2
SHRTX
INX
GX
GATX
0
X
X
X
X
X
L
1
0
0
X
X
X
L
1
0
1
X
X
X
L
1
1
0
X
X
X
L
1
1
1
1
0
0
L
1
1
1
1
1
X
H
1
1
1
1
X
1
H
1
1
1
0
X
X
L
1
1→0
1
X
X
→0
→L
1
1
1→0
X
X
GX
1
1
0→1
X
0
GX
Table 8. Fault Data Encoding
CHANNEL 0
D1
D0
0
0
NO FAULT
→L
0
1
OPEN LOAD
→GX
1
0
SHORT TO GND
1
1
SHORTED LOAD
Gate Drivers
The non−inverting GATX drivers are symmetrical
resistive switches (350 W typ.) to the VCC2 and VSS
voltages. While the outputs are designed to provide
symmetrical gate drive to an external MOSFET, load
current switching symmetry is dependent on the
characteristics of the external MOSFET and its load.
Figure 12 shows the gate driver block diagram.
DX0
DX1
tFR
R2 | R 5
MX
IN X
GX
ENA1
ENA2
POR
FILTER
TIMER
ENCODING
LOGIC
S
LATCH OFF /
AUTO RE−TRY
_
EN
R
FAULT
DETECTION
SHRTX
Blanking and Filter Timers
Blanking timers are used to allow drain feedback to
stabilize after a channel is commanded to change states.
Filter timers are used to suppress glitches while a channel
is in a stable state.
A turn−on blanking timer is started when a channel is
commanded on. Drain feedback is sampled after tBL(ON).
A turn−off blanking timer is started when a channel is
commanded off. Drain feedback is sampled after tBL(OFF).
A filter timer is started when a channel is in a stable state
and a fault detection threshold associated with that state has
been crossed. Drain feedback is sampled after tFF.
Blanking timers for all channels are started when both
ENA1 and ENA2 go high or when either ENAX goes high
while the other is high. The blanking time for each channel
depends on the commanded state when ENAX goes high.
While each channel has independent blanking and filter
timers, the parameters for the tBL(ON), tBL(OFF), and tFF
times are the same for all channels.
50
DRNX
BLANKING
TIMER
STATUS
VSS
VCC2
350
DRIVER
GAT X
VSS
Figure 12. Gate Driver Channel
Fault Diagnostics and Behavior
Each channel has independent fault diagnostics and
employs blanking and filter timers to suppress false faults.
An external MOSFET is monitored for fault conditions by
connecting its drain to a channel’s DRNX feedback input
through an external series resistor.
When either ENA1 or ENA2 is low, diagnostics are
disabled. When both ENA1 and ENA2 are high,
diagnostics are enabled.
Shorted load (or short to VLOAD) faults can be detected
when a driver is on. Open load or short to GND faults can
be detected when a driver is off.
Shorted Load Detection
An external reference voltage applied to the FLTREF
input serves as a common reference for all channels
(Figure 13). The FLTREF voltage must be within the range
of 0 to VCC1−2.0 V and can be derived via a voltage divider
between VCC1 and GND.
Shorted load detection thresholds can be programmed
via SPI in four 25% increments that are ratiometric to the
applied FLTREF voltage. Separate thresholds can be
selected for channels 0−2 and for channels 3−5 (Table 4).
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NCV7517B
Fault Recovery Refresh Time
Refresh time for shorted load faults is SPI programmable
to one of two values for channels 0−2 (register bit R2) and
for channels 3−5 (register bit R5) via the Refresh and
Reference register (Table 4).
A global refresh timer with taps at nominally 10 ms and
40 ms is used for auto−retry timing. The first faulted
channel triggers the timer and the full refresh period is
guaranteed for that channel. An additional faulted channel
may initially retry immediately after its turn−on blanking
time, but subsequent retries will have the full refresh time
period.
If all channels in a group (e.g. channels 0−2) become
faulted, they will become synchronized to the selected
refresh period for that group. If all channels become faulted
and are set for the same refresh time, all will become
synchronized to the refresh period.
A shorted load fault is detected when a channel’s DRNX
feedback is greater than its selected fault reference after
either the turn−on blanking or the filter has timed out.
VCC1
CHANNELS 0−2
FLTREF
RX1
0 − 3V
3
VCC1
2
1
0
+
RX2
2X4
DECODER
OA
−
R
R1
R0
75%
KELVIN
REGISTER 2
BITS
R
50%
R
R4
R3
25%
R
3
2
1
0
2X4
DECODER
CHANNELS 3−5
Figure 13. Shorted Load Reference Generator
Open Load and Short to GND Detection
A window comparator with fixed references
proportional to VCC1 along with a pair of bias currents is
used to detect open load or short to GND faults when a
channel is off. Each channel’s DRNX feedback is compared
to the references after either the turn−off blanking or the
filter has timed out. Figure 14 shows the DRNX bias and
fault detection zones. The diagnostics are disabled and the
bias currents are turned off when ENAX is low.
No fault is detected if the feedback voltage at DRNX is
greater than the VOL open load reference. If the feedback
is less than the VSG short to GND reference, a short to GND
fault is detected. If the feedback is less than VOL and
greater than VSG, an open load fault is detected.
Shorted Load Fault Recovery
Shorted load fault disable mode for each channel is
individually SPI programmable via the MX bits in the
device’s Disable Mode register (Table 3).
When latch−off mode is selected the corresponding
GATX output is turned off upon detection of a fault. Fault
recovery is initiated by toggling (ON→OFF→ON) the
channel’s respective INX parallel input, serial GX bit, or
ENA2.
When auto−retry mode is selected (default mode) the
corresponding GATX output is turned off for the duration
of the programmed fault refresh time (tFR) upon detection
of a fault. The output is automatically turned back on (if
still commanded on) when the refresh time ends. The
channel’s DRNX feedback is resampled after the turn−on
blanking time. The output will automatically be turned off
if a fault is again detected. This behavior will continue for
as long as the channel is commanded on and the fault
persists.
In either mode, a fault may exist at turn−on or may occur
some time afterward. To be detected, the fault must exist
longer than either tBL(ON) at turn−on or longer than tFF
some time after turn−on. The length of time that a
MOSFET stays on during a shorted load fault is thus limited
to either tBL(ON) or tFF.
In auto−retry mode, a persistent shorted load fault will
result in a low duty cycle (tFD [ tBL(ON)/tFR) for the
affected channel and help prevent thermal failure of the
channel’s MOSFET.
CAUTION − CONTINUOUS INPUT TOGGLING VIA
INX, GX or ENA2 WILL OVERRIDE EITHER DISABLE
MODE. Care should be taken to service a shorted load fault
quickly when one has been detected.
I DRNX
Short to
GND
Open
Load
No
Fault
I OL
0
−ISG
VDRNX
VSG
VCTR
VOL
Figure 14. DRNX Bias and Fault Detection Zones
Figure 15 shows the simplified detection circuitry. Bias
currents ISG and IOL are applied to a bridge along with bias
voltage VCTR (50% VCC1 typ.).
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NCV7517B
Status Flag (STAB)
The open−drain active−low status flag output can be used
to provide a host controller with information about the state
of a channel’s DRNx feedback. Feedback from all channels
is logically ORed to the flag (Figure 16). The STAB
outputs from several devices can be wire−ORed to a
common pullup resistor connected to the controller’s 3.3 or
5.0 V VDD supply.
When ENA1 is high, the drain feedback from a channel’s
DRNx input is compared to the VOL reference without
regard to ENA2 or the commanded state of the channel’s
driver. The flag is reset and disabled when ENA1 is low or
when all mask bits are set. See Table 9 for additional
details.
The flag is set (low) when the feedback voltage is less
than VOL, and the channel’s mask bit (Table 5) is cleared.
The flag is reset (hi−Z) when the feedback voltage is
greater than VOL, and the channel’s mask bit is cleared.
VCC1
I SG
VLOAD
A
−
CMP1
VOL
D3
D1
+
50
+
B
DZ1
D4
CMP2
−
1600
D2
(VCL)
RLOAD
DRNX
VX
RDX
RSG
VSG
VCTR
+
_
I OL
+VOS
Figure 15. Short to GND/Open−Load Detection
When a channel is off and VLOAD and RLOAD are
present, RSG is absent, and VDRNX >> VCTR, bias current
IOL is supplied from VLOAD to ground through external
resistors RLOAD and RDX, and through the internal 1650 W
resistance and bridge diode D2. Bias current ISG is supplied
from VCC1 to VCTR through D3. No fault is detected if the
feedback voltage (VLOAD minus the total voltage drop
caused by ISG and the resistance in the path) is greater than
VOL.
When either VLOAD or RLOAD and RSG are absent, the
bridge will self−bias so that the voltage at DRNX will settle
to about VCTR. An open load fault can be detected since the
feedback is between VSG and VOL.
Short to GND detection can tolerate up to a 1.0 V offset
(VOS) between the NCV7517B’s GND and the short. When
RSG is present and VDRNX << VCTR, bias current ISG is
supplied from VCC1 to VOS through D1, the internal
1650 W, and the external RDX and RSG resistances. Bias
current IOL is supplied from VCTR to ground through D4.
A “weak” short to GND can be detected when either
VLOAD or RLOAD is absent and the feedback (VOS plus the
total voltage rise caused by IOL and the resistance in the
path) is less than VOL.
When VLOAD and RLOAD are present, a voltage divider
between VLOAD and VOS is formed by RLOAD and RSG. A
“hard” short to GND may be detected in this case
depending on the ratio of RLOAD and RSG and the values of
RDX, VLOAD, and VOS.
Note that the comparators see a voltage drop or rise due
only to the 50 W internal resistance and the bias currents.
This produces a small difference in the comparison to the
actual feedback voltage at the DRNX input.
Several equations for choosing RDX and for predicting
open load or short to GND resistances, and a discussion of
the dynamic behavior of the short to GND/open load
diagnostic are provided in the Applications Information
section of this data sheet.
OTHER
CHANNELS
KX
VOL
DRNX
−
STAB
D
CMP1
+
Q
A
500 kHz
CLR
POR
ENA1
Figure 16. STAB Flag Logic
Fault Flag (FLTB)
The open−drain active−low fault flag output can be used
to provide immediate fault notification to a host controller.
Fault detection from all channels is logically ORed to the
flag (Figure 17). The FLTB outputs from several devices
can be wire−ORed to a common pullup resistor connected
to the controller’s 3.3 or 5.0 V VDD supply.
The flag is set (low) when a channel detects any fault, the
channel’s mask bit (Table 5) is cleared, and both ENAx and
CSB are high. The flag is reset (hi−Z) and disabled when
either ENA1 or CSB is low. See Table 9 for additional
details.
KX
FAULT X
ENA2
OTHER
CHANNELS
FLTB
S
Q
R
ENA1
POR
CSB
(RESET DOMINANT)
Figure 17. FLTB Flag Logic
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NCV7517B
Fault Detection and Capture
Each channel of the NCV7517B is capable of detecting
shorted load faults when the channel is on, and short to
ground or open load faults when the channel is off. Each
fault type is uniquely encoded into two−bit per channel
fault data. A drain feedback input for each channel
compares the voltage at the drain of the channel’s external
MOSFET to several internal reference voltages. Separate
detection references are used to distinguish the three fault
types, and blanking and filter timers are used respectively
to allow for output state transition settling and for glitch
suppression.
Fault diagnostics are disabled when either enable input
is low. When both enable inputs are high, each channel’s
drain feedback input is continuously compared to
references appropriate to the channel’s input state to detect
faults, but the comparison result is only latched at the end
of either a blanking or filter timer event.
Blanking timers for all channels are triggered when
either enable input changes state from low to high while the
other enable input is high, or when both enable inputs go
high simultaneously. A single channel’s blanking timer is
triggered when its input state changes. If the comparison of
the feedback to a reference indicates an abnormal condition
when the blanking time ends, a fault has been detected and
the fault data is latched into the channel’s fault latch.
A channel’s filter timer is triggered when its drain
feedback comparison state changes. If the change indicates
an abnormal condition when the filter time ends, a fault has
been detected and the fault data is latched into the channel’s
fault latch.
Thus, a state change of the inputs (ENAX, INX or GX) or
a state change of an individual channel’s feedback (DRNX)
comparison must occur for a timer to be triggered and a
detected fault to be captured.
flag is reset when CSB goes low at the start of the SPI
frame. Fault latches are cleared and re−armed when CSB
goes high at the end of the SPI frame only if a valid frame
has occurred; otherwise the latches retain the detected fault
data until a valid frame occurs. The FLTB flag will be set
if a fault is still present.
Fault latches for all channels and the FLTB flag can also
be cleared and re−armed by toggling ENA1 H−L−H. A full
I/O truth table is given in Table 9.
Fault Data Readback Examples
Several examples are shown to illustrate fault detection,
capture and SPI read−back of fault data for one channel. A
normal SPI frame returns 16 bits of data but only the two
bits of serial data for the single channel are shown for
clarity.
The examples assume:
The NCV7517B is configured as in Figure 2
Both enable inputs are high
The channel’s flag mask bit is cleared
Disable mode is set to auto−retry
The parallel input commands the channel
SPI frame is always valid
•
•
•
•
•
•
Shorted Load Detected
Refer to Figure 18. The channel is commanded on when
INX goes high. GATX goes high and the timers are started.
At “A”, the STAB flag is set as the DRNX feedback falls
through the VOL threshold. A SPI frame sent soon after the
INX command returns data indicating “no fault.”
The blanking time ends and the filter timer is triggered
as DRNX rises through the FLTREF threshold. The STAB
flag is reset as DRNX passes through the VOL threshold.
DRNX is nearly at VLOAD when the filter time ends at “B”.
A shorted load fault is detected and captured by the fault
latch, GATX goes low, the FLTB flag is set, and the
auto−retry timer is started.
An SPI frame sent soon after “B” returns data indicating
“shorted load”. The FLTB flag is reset when CSB goes low.
At “C” when CSB goes high at the end of the frame, the
fault latch is cleared and re−armed. Since INX and the
DRNX feedback are unchanged, FLTB and the fault latch
are set and the fault is recaptured.
When the auto−retry timer ends at “D”, GATX goes high
and the blanking and filter timers are started. Since INX and
DRNX are unchanged, GATX goes low when the blanking
time ends at “E” and the auto−retry timer is started.
Read−back data continues to indicate a “shorted load” and
the FLTB flag continues to be set while the fault persists.
Fault Capture, SPI Communication, and SPI
Frame Error Detection
The fault capture and frame error detection strategies of
the NCV7517B combine to ensure that intermittent faults
can be captured and identified, and that the device cannot
be inadvertently reprogrammed by a communication error.
The NCV7517B latches a fault when it is detected, and
frame error detection will not allow any register to accept
data if an invalid frame occurred.
When a fault has been detected, the FLTB flag is set and
fault data is latched into a channel’s fault latch. The latch
captures and holds the fault data and ignores subsequent
fault data for that channel until a valid SPI frame occurs.
Fault data from all channels is transferred from each
channel’s fault latch into the SPI shift register and the FLTB
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NCV7517B
INx
1
0
FAULT DETECTED
1
GATx
0
DRNx
VLOAD
VOL
FLTREF
0
A
1
STAB
BLANK
TIMER
1
FILTER
TIMER
1
FAULT
LATCH
1
CSB
D
0
0
tFR
tBL(ON)
0
0
E
B
tFR
tBL(ON)
INTERNAL
SIGNALS
C
tFF
00
11
11
11
11
11
1
0
1
SO
0
00
11
11
1
FLTB
0
Figure 18. Shorted Load Detected
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18
11
11
11
NCV7517B
Shorted Load Recovery
Figure 19 is a continuation of Figure 18. INX is high
when the auto−retry timer ends. GATX goes high and the
blanking and filter timers are started. The fault is removed
before the blanking timer ends, and DRNX starts to fall. As
DRNX passes through the VOL threshold at “A”, the STAB
flag is set. DRNX continues to fall and settles below the
FLTREF threshold.
An SPI frame is sent during the blanking time and returns
data indicating a “shorted load” fault. Although the fault is
removed, updates to the fault latches are suppressed while
a blanking or filter timer is active. The same fault is
captured again and FLTB is set when CSB goes high. At
“B” the blanking time ends and the channel’s fault bits will
INx
GATx
1
D
0
1
0
FAULT REMOVED
VLOAD
DRNx
indicate “no fault” but because the latched data has not yet
been read, the data remains unchanged.
The SPI frame sent after the blanking time ends returns
a “shorted load” fault because the previous frame occurred
during the blanking time. Since the channel’s fault bits
indicate “no fault”, FLTB is reset and the fault latch is
updated at “C” when CSB goes high. If another SPI frame
is sent before “D”, the returned data will indicate “no
fault”.
The channel is commanded off at “D”. GATX goes low
and the timers are started. DRNX starts to rise and the STAB
flag is reset as DRNX passes through the VOL threshold.
The SPI frame sent at “E” returns data indicating “no
fault”.
A
VOL
FLTREF
0
STAB
1
0
B
BLANK
TIMER
1
FILTER
TIMER
1
FAULT
LATCH
1
CSB
tFR
0
INTERNAL
SIGNALS
tFF
0
0
tBL(OFF)
tBL(ON)
11
11
tFF
11
00
1
C
0
E
1
SO
FLTB
0
11
11
11
1
0
Figure 19. Shorted Load Recovery
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19
00
NCV7517B
Short to GND/Open Load
Figure 20 illustrates turn−off with an open or high
resistance load when some capacitance is present at DRNX.
In the case of an open load, DRNX rises and settles to VCTR.
In the case of a high resistance load, DRNX may continue
to rise and may eventually settle to VLOAD.
The channel is commanded off. GATX goes low and the
timers are started. DRNX starts to rise and is below the VSG
threshold when the blanking time ends at “A”. A short to
GND fault is detected and captured by the fault latch, and
the FLTB flag is set.
DRNX continues to rise and as it passes through the VSG
threshold at “B”, the filter timer is triggered. At the end of
the filter time, the channel’s fault bits will indicate an
INx
DRNx
GATx
“open load” but because the latched data has not yet been
read, the data remains unchanged.
An SPI frame sent shortly after “B” returns data
indicating “short to GND” and the fault latch is updated at
“C” when CSB goes high. The next three frames sent after
“C” return data indicating an “open load”.
The STAB flag is reset at “D” as DRNX passes through
the VOL threshold. Note that the filter timer is not triggered
as DRNX passes from a fault state to a good state. The
channel’s fault bits will indicate “no fault” but because the
latched data has not yet been read, the data remains
unchanged.
The fault latch is updated at “E” when CSB goes high and
the FLTB flag remains reset. The next SPI frame sent
returns data indicating “no fault”.
1
0
1
0
VLOAD
VOL
VCTR
VSG
0
STAB
1
FILTER
TIMER
1
FAULT
LATCH
1
SO
FLTB
B
C
0
BLANK
TIMER
CSB
D
A
1
0
tBL(OFF)
tFF
0
0
00
INTERNAL
SIGNALS
tFF
10
01
01
E
01
00
1
0
1
0
00
10
01
01
1
0
Figure 20. Short to GND/Open Load
www.onsemi.com
20
01
00
NCV7517B
Table 9. I/O Truth Table
Inputs
Outputs*
POR
ENA1
ENA2
CSB
KX
INX
GX
DRNX
GATX
FLTB
STAB
DX1DX0
0
X
X
X
→0
X
→0
X
→L
→Z
→Z
→00
1
0
X
X
X
X
X
X
L
Z
Z
00
ENA1
1
1
0
X
KX
X
GX
X
L
FLTB
STAB
DX1DX0
ENA2
1
1→0
1
X
KX
X
→0
X
→L
→Z
→Z
→00
1
1
1→0
X
KX
X
GX
X
→L
FLTB
STAB
DX1DX0
1
1
X
X
0
X
X
X
L
Z
Z
−
FLAGS MASKED
1
1
0
X
1
X
X
> VOL
L
−
Z
−
STAB RESET
1
1
0
X
1
X
X
< VOL
L
−
L
−
STAB SET
1
1
0
X
1→0
X
X
< VOL
L
−
L→Z
−
STAB RESET
1
1
0
X
0→1
X
X
< VOL
L
−
Z→L
−
STAB SET
1
1
1
X
1
0
0
> VOL
L
Z
Z
00
FLAGS RESET
1
1
1
1
1
0
0
VSG<V<VOL
L
L
L
01
FLAGS SET
1
1
1
X
1→0
0
0
VSG<V<VOL
L
L
L→Z
01
STAB RESET
1
1
1
X
0→1
0
0
VSG<V<VOL
L
L
01
STAB SET
1
1
1
1→0
1
0
0
VSG<V<VOL
L
L→Z
L
01
FLTB RESET
1
1
1
0→1
1
0
0
VSG<V<VOL
L
Z→L
L
01
FLTB SET
1
1
1
1
1
0
0
< VSG
L
L
L
10
FLAGS SET
1
1
1
X
1→0
0
0
< VSG
L
L
L→Z
10
STAB RESET
1
1
1
X
0→1
0
0
< VSG
L
L
Z→L
10
STAB SET
1
1
1
1→0
1
0
0
< VSG
L
L→Z
L
10
FLTB RESET
1
1
1
0→1
1
0
0
< VSG
L
Z→L
L
10
FLTB SET
1
1
1
X
1
1
X
< VFLTREF
H
Z
L
00
STAB SET
1
1
1
1
1
1
X
VFLTREF<V<VOL
L
L
L
11
FLAGS SET
1
1
1
X
1→0
1
X
VFLTREF<V<VOL
L
L
L→Z
11
STAB RESET
1
1
1
X
0→1
1
X
VFLTREF<V<VOL
L
L
Z→L
11
STAB SET
1
1
1
1→0
1
1
X
VFLTREF<V<VOL
L
L→Z
L
11
FLTB RESET
1
1
1
0→1
1
1
X
VFLTREF<V<VOL
L
Z→L
L
11
FLTB SET
1
1
1
1
1
1
X
> VOL
L
L
Z
11
STAB RESET
1
1
1
X
1
X
1
< VFLTREF
H
Z
L
00
STAB SET
1
1
1
1
1
X
1
VFLTREF<V<VOL
L
L
L
11
FLAGS SET
1
1
1
X
1→0
X
1
VFLTREF<V<VOL
L
L
L→Z
11
STAB RESET
1
1
1
X
0→1
X
1
VFLTREF<V<VOL
L
L
Z→L
11
STAB SET
1
1
1
1→0
1
X
1
VFLTREF<V<VOL
L
L→Z
L
11
FLTB RESET
1
1
1
0→1
1
X
1
VFLTREF<V<VOL
L
Z→L
L
11
FLTB SET
1
1
1
1
1
X
1
> VOL
L
L
Z
11
STAB RESET
* Output states after blanking and filter timers end and when channel is set to latch−off mode.
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21
COMMENT
POR RESET
ENA1 RESET
ENA2 DISABLE
NCV7517B
APPLICATION GUIDELINES
General
Unused DRNX inputs should be connected to VCC1 to
prevent false open load faults. Unused parallel inputs
should be connected to GND and unused enable inputs
should be connected to VCC1. The mask bit for each unused
channel should be ‘set’ (see Table 5) to prevent activation
of the flags and the user’s software should be designed to
ignore fault information for unused channels. For best
shorted−load detection accuracy, the external MOSFET
source terminals should be star−connected and the
NCV7517B’s GND pin, and the lower resistor in the fault
reference voltage divider should be Kelvin connected to
the star (see Figures 2 and 13).
Consideration of auto−retry fault recovery behavior is
necessary from a power dissipation viewpoint (for both the
NCV7517B and the MOSFETs) and also from an EMI
viewpoint.
Driver slew rate and turn−on/off symmetry can be
adjusted externally to the NCV7517B in each channel’s
gate circuit by the use of series resistors for slew control,
or resistors and diodes for symmetry. Any benefit of EMI
reduction by this method comes at the expense of increased
switching losses in the MOSFETs.
The channel fault blanking timers must be considered
when choosing external components (MOSFETs, slew
control resistors, etc.) to avoid false faults. Component
choices must ensure that gate circuit charge/discharge
times stay within the turn−on/turn−off blanking times.
The NCV7517B does not have integral drain−gate
flyback
clamps.
Clamp
MOSFETs, such as
ON Semiconductor’s NID9N05CL, are recommended
when driving unclamped inductive loads. This flexibility
allows choice of MOSFET clamp voltages suitable to each
application.
clamp power is limited to the maximum allowable junction
temperature.
To limit power in the DRNX input clamps and to ensure
proper open load or short to GND detection, the RDX
resistor must be dimensioned according to the following
constraint equations:
RDX(MIN) +
VPK−VCL(MIN)
ICL(MAX)
(eq. 2)
VSG−|VOS|
|ISG|
(eq. 3)
RDX(MAX) +
where VPK is the peak transient drain voltage, VCL is the
DRNX input clamp voltage, ICL(MAX) is the input clamp
current, and VSG and ISG are the respective short to GND
fault detection voltage and diagnostic current, and VOS is
the allowable offset (1.0 V max) between the NCV7517B’s
GND and the short.
Once RDX is chosen, the open load and short to GND
detection resistances in the application can be predicted:
V
−V
ROL w LOAD OL * RDX
IOL
(eq. 4)
RLOAD(VSG " VOS−|ISG|RDX)
(eq. 5)
RSG v
VLOAD−VSG ) |ISG|(RDX ) RLOAD)
Using the data sheet values for VCL(MIN) = 27 V,
ICL(MAX) = 10 mA, and choosing VPK = 55 V as an
example, Equation 2 evaluates to 2.8 kW minimum.
Choosing VCC1 = 5.0 V and using the typical data sheet
values for VSG = 30%VCC1, ISG = 20 mA, and choosing
VOS = 0, Equation 3 evaluates to 75 kW maximum.
Selecting RDX = 6.8 kW "5%, VCC1 = 5.0 V, VLOAD =
12.0 V, VOS = 0 V, RLOAD = 555 W, and using the typical
data sheet values for VOL, IOL, VSG, and ISG, Equation 4
predicts an open load detection resistance of 130.7 kW and
Equation 5 predicts a short to GND detection resistance of
71.1 W. When RDX and the data sheet values are taken to
their extremes, the open load detection range is 94.1 kW v
ROL v 273.5 kW, and the short to GND detection range is
59.2 W v RSG v 84.4 W.
DRNX Feedback Resistor
Each DRNX feedback input has a clamp to keep the
applied voltage below the breakdown voltage of the
NCV7517B. An external series resistor (RDX) is required
between each DRNX input and MOSFET drain. Channels
may be clamped sequentially or simultaneously but total
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22
NCV7517B
PACKAGE DIMENSIONS
LQFP32, 7x7
CASE 561AB
ISSUE O
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23
NCV7517B
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