LV8740V D

Ordering number : ENA1864A
LV8740V
Monolithic Linear IC
PWM Current Control Stepper
Motor Driver
http://onsemi.com
Overview
The LV8740V is a 2-channel H-bridge driver IC that can switch a stepper motor driver, which is
capable of micro-step drive and supports Quarter-step excitation, and two channels of a brushed
DC motor driver, which supports forward, reverse, brake, and standby of a motor. It is ideally
suited for driving brushed DC motors and stepper motors used in office equipment and
amusement applications.
Function
• Single-channel PWM current control stepper motor driver (selectable with DC motor driver channel 2) incorporated.
• On resistance (upper side : 0.3Ω ; lower side : 0.2Ω ; total of upper and lower : 0.5Ω ; Ta = 25°C, IO = 2.5A)
• Excitation mode can be set to Full-step, Half-step full torque, Half-step , or Quarter-step
• Excitation step proceeds only by step signal input
• Motor current selectable in four steps
• BiCDMOS process IC
• Output short-circuit protection circuit (selectable from latch-type or auto reset-type) incorporated
• Unusual condition warning output pins
• No control supply required
Specifications
Absolute Maximum Ratings at Ta = 25°C
Parameter
Symbol
Conditions
Ratings
Unit
Supply voltage 1
VM max
VM , VM1 , VM2
38
V
Output peak current
IO peak
tw ≤ 10ms, duty 20%, Each 1ch
3.0
A
Output current
IO max
Logic input voltage
VIN
Each 1ch
ST , OE , DM , MD1/DC11 , MD2/DC12 ,
2.5
A
-0.3 to +6.0
V
FR/DC21 , STP/DC22 , RST , EMM , ATT1 , ATT2
MONI/EMO input voltage
VMONI/VEMO
Allowable power dissipation
Pd max
*
-0.3 to +6.0
V
3.45
W
Operating temperature
Topr
-30 to +85
°C
Storage temperature
Tstg
-55 to +150
°C
* Specified circuit board :
90×90×1.6mm3
: 2-Layer glass epoxy printed circuit board with back mounting.
Caution 1) Absolute maximum ratings represent the value which cannot be exceeded for any length of time.
Caution 2) Even when the device is used within the range of absolute maximum ratings, as a result of continuous usage under high temperature, high current,
high voltage, or drastic temperature change, the reliability of the IC may be degraded. Please contact us for the further details.
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating
Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.
ORDERING INFORMATION
See detailed ordering and shipping information on page 25 of this data sheet.
Semiconductor Components Industries, LLC, 2013
April, 2013
42413NK 20130225-S00006 No.A1864-1/25
LV8740V
Recommended Operating Conditions at Ta = 25°C
Parameter
Symbol
Conditions
Ratings
Unit
Supply voltage range
VM
VM , VM1 , VM2
9 to 35
V
Logic input voltage
VIN
ST , OE , DM , MD1/DC11 , MD2/DC12 ,
0 to 5.5
V
0 to 3.0
V
FR/DC21 , STP/DC22 , RST , EMM , ATT1 ,
ATT2
VREF input voltage range
VREF
Electrical Characteristics at Ta = 25°C, VM = 24V, VREF = 1.5V
Parameter
Symbol
Standby mode current drain
Current drain
IMstn
IM
Conditions
Ratings
min
typ
ST = ”L” , I(VM)+I(VM1)+I(VM2)
ST = ”H”, OE = ”L”, no load
Unit
max
180
250
μA
3
5
mA
I(VM)+I(VM1)+I(VM2)
VREG5 output voltage
Vreg5
Thermal shutdown temperature
Thermal hysteresis width
IO=-1mA
4.7
5.0
5.3
V
TSD
Design guarantee
150
180
210
°C
ΔTSD
Design guarantee
°C
40
Motor Driver
Output on-resistance
Output leakage current
Diode forward voltage
ST pin input current
Logic pin input current
IO = 2.5A, Upper-side on resistance
0.3
0.4
Rond
IO = 2.5A, Lower-side on resistance
0.2
0.25
Ω
IOleak
VM=35V
50
μA
VD
ID = -2.5A
ISTL
VIN = 0.8V
ISTH
VIN = 5V
IINL
(other ST pin)
Logic input voltage
Ω
Ronu
OE , DM , MD1/DC11 , MD2/DC12 ,
1.1
1.3
V
3
8
15
μA
48
80
112
μA
3
8
15
μA
50
FR/DC21 , STP/DC22 , RST , EMM , ATT1 ,
High
Low
Current setting
Quarter
comparator
step
threshold voltage
resolution
(Current step
switch)
Half step
IINH
ATT2 , VIN = 0.8V
VIN = 5V
30
70
μA
VINh
ST , OE , DM , MD1/DC11 , MD2/DC12 ,
2.0
5.5
V
VINl
FR/DC21 , STP/DC22 , RST , EMM , ATT1 ,
0
0.8
V
Vtdac0_W
Full step
0.290
0.300
0.310
V
Vtdac1_W
Step 1 (Initial state+1)
0.260
0.270
0.280
V
Vtdac2_W
Step 2 (Initial state+2)
0.200
0.210
0.220
V
Vtdac3_W
Step 3 (Initial state+3)
0.095
0.105
0.115
V
Vtdac0_H
Step 0 (When initialized: channel 1
0.290
0.300
0.310
V
Vtdac2_H
Step 2 (Initial state+1)
0.200
0.210
0.220
V
Step 0 (Initial state, channel 1 comparator
0.290
0.300
0.310
V
comparator level)
Vtdac0_HF
resolution
(full torque)
Step 0(When initialized : channel 1
comparator level)
resolution
Half step
ATT2
level)
Vtdac2_HF
Vtdac2_F
Step 2 (Initial state+1)
0.290
0.300
0.310
V
Step 2
0.290
0.300
0.310
V
resolution
Current setting comparator
Vtatt00
ATT1=L, ATT2=L
0.290
0.300
0.310
V
threshold voltage
Vtatt01
ATT1=H, ATT2=L
0.190
0.200
0.210
V
Vtatt10
ATT1=L, ATT2=H
0.140
0.150
0.160
V
Vtatt11
ATT1=H, ATT2=H
0.090
0.100
0.110
Fchop
RCHOP = 20kΩ
45
62.5
75
(Current attenuation rate switch)
Chopping frequency
VREF pin input current
MONI pin saturation voltage
Iref
VREF = 1.5V
Vsatmon
IMONI=1mA
V
kHz
μA
-0.5
50
100
mV
28.7
29.8
V
0.5
ms
150
kHz
Charge pump
VG output voltage
VG
28
Rise time
tONG
VG = 0.1μF , Between CP1-CP2 0.1uF
Oscillator frequency
Fosc
RCHOP = 20kΩ
ST=”H” → VG=VM+4V
90
125
Continued on next page.
No.A1864-2/25
LV8740V
Continued from preceding page.
Parameter
Symbol
Ratings
Conditions
min
typ
Unit
max
Output short-circuit protection
EMO pin saturation voltage
CEM pin charge current
CEM pin threshold voltage
Vsatemo
Icem
Iemo = 1mA
Vcem=0V
Vtcem
50
100
mV
7
10
13
μA
0.8
1.0
1.2
V
Pin Assignment
VG 1
44 OUT1A
VM 2
43 OUT1A
CP2 3
42 PGND1
CP1 4
41 NC
VREG5 5
40 NC
ATT2 6
39 VM1
ATT1 7
38 VM1
EMO 8
37 RF1
CEM 9
36 RF1
EMM 10
35 OUT1B
RCHOP 11
MONI 12
34 OUT1B
LV8740V
RST 13
33 OUT2A
32 OUT2A
STP/DC22 14
31 RF2
FR/DC21 15
30 RF2
MD2/DC12 16
29 VM2
MD1/DC11 17
28 VM2
DM 18
27 NC
OE 19
26 NC
ST 20
25 PGND2
VREF 21
24 OUT2B
GND 22
23 OUT2B
Top view
No.A1864-3/25
LV8740V
Package Dimensions
unit : mm (typ)
3285B
TOP VIEW
SIDE VIEW
BOTTOM VIEW
15.0
44
0.5
(3.6)
7.6
5.6
(7.8)
1
2
0.65
0.2
0.22
1.7 MAX
(0.68)
0.05 (1.5)
SIDE VIEW
SSOP44J(275mil)
Pd max - Ta
6.0
Four-layer circuit board 1*1
5.50
Allowable power dissipation, Pdmax - W
5.0
4.0
Four-layer circuit board 2*2
3.45
3.0
3.80
Two-layer circuit board 1*1
2.86
2.65
Two-layer circuit board 2*2
1.98
2.0
1.79
1.38
1.0
*1 With components mounted on the exposed die-pad board
*2 With no components mounted on the exposed die-pad board
0
10
30
50
70
90
Ambient temperature, Ta - C
No.A1864-4/25
LV8740V
Substrate Specifications (Substrate recommended for operation of LV8740V)
Size
: 90mm × 90mm × 1.6mm
Material
: Glass epoxy
Copper wiring density : L1 = 85% / L2 = 90%
L1 : Copper wiring pattern diagram
L2 : Copper wiring pattern diagram
Cautions
1) The data for the case with the Exposed Die-Pad substrate mounted shows the values when 90% or more of the
Exposed Die-Pad is wet.
2) For the set design, employ the derating design with sufficient margin.
Stresses to be derated include the voltage, current, junction temperature, power loss, and mechanical stresses such as
vibration, impact, and tension.
Accordingly, the design must ensure these stresses to be as low or small as possible.
The guideline for ordinary derating is shown below :
(1)Maximum value 80% or less for the voltage rating
(2)Maximum value 80% or less for the current rating
(3)Maximum value 80% or less for the temperature rating
3) After the set design, be sure to verify the design with the actual product.
Confirm the solder joint state and verify also the reliability of solder joint for the Exposed Die-Pad, etc.
Any void or deterioration, if observed in the solder joint of these parts, causes deteriorated thermal conduction,
possibly resulting in thermal destruction of IC.
No.A1864-5/25
MONI
PGND
GND
VREF
VREG5
+
-
VM
LVS
TSD
+
-
RCHOP
Oscillation
circuit
Regulator
ATT2
Attenuator
(4 levels
selectable)
ST ATT1
Charge pump
Output preamplifier stage
RF1
OUT1B VM1
VM2 OUT2A
RF2
DM
EMM
Current
selection
(W1-2/1-2/
1-2Full/2)
Current
selection
(W1-2/1-2/
1-2Full/2)
MD1/
DC11
+
MD2/ FR/ STP/ RST OE
DC12 DC21 DC22
Output control logic
OUT2B
+
OUT1A
Output preamplifier stage
VG
Output preamplifier stage
CP1
Output preamplifier stage
CP2
CEM
EMO
LV8740V
Block Diagram
No.A1864-6/25
LV8740V
Pin Functions
Pin No.
Pin name
Description
1
VG
2
VM
Charge pump capacitor connection pin
Motor power supply connection pin
3
CP2
Charge pump capacitor connection pin
4
CP1
Charge pump capacitor connection pin
5
VREG5
Internal power supply capacitor connection pin
6
ATT2
Motor holding current switching pin
7
ATT1
Motor holding current switching pin
8
EMO
Output short-circuit state warning output pin
9
CEM
Pin to connect the output short-circuit state detection time setting capacitor
10
EMM
Over current mode switching pin
11
RCHOP
Chopping frequency setting resistor connection pin
12
MONI
Position detection monitor pin
13
RST
Reset signal input pin
14
STP/DC22
STM STEP signal input pin/DCM2 output control input pin
15
FR/DC21
STM forward/reverse rotation signal input pin/DCM2 output control input pin
16
MD2/DC12
STM excitation mode switching pin/DCM1 output control input pin
17
MD1/DC11
STM excitation mode switching pin/DCM1 output control input pin
18
DM
Drive mode (STM/DCM) switching pin
19
OE
Output enable signal input pin
20
ST
Chip enable pin
21
VREF
Constant current control reference voltage input pin
22
GND
Signal system ground
23, 24
OUT2B
Channel 2 OUTB output pin
25
PGND2
Channel 2 Power system ground
VM2
Channel 2 motor power supply connection pin
28, 29
30, 31
RF2
Channel 2 current-sense resistor connection pin
32, 33
OUT2A
Channel 2 OUTA output pin
34, 35
OUT1B
Channel 1 OUTB output pin
36, 37
RF1
Channel 1 current-sense resistor connection pin
38, 39
VM1
Channel 1 motor power supply pin
42
PGND1
Channel 1 Power system ground
43, 44
OUT1A
Channel 1 OUTA output pin
26, 27
NC
40, 41
No Connection
(No internal connection to the IC)
No.A1864-7/25
LV8740V
Equivalent Circuits
Pin No.
Pin
6
ATT2
7
ATT1
10
EMM
13
RST
14
STP/DC22
15
FR/DC21
16
MD2/DC12
17
MD1/DC11
18
DM
19
OE
Equivalent Circuit
VREG5
GND
20
ST
VREG5
GND
23, 24
OUT2B
25
PGND2
28, 29
VM2
30, 31
RF2
32, 33
OUT2A
34, 35
OUT1B
36, 37
RF1
38, 39
VM1
42
PGND1
43, 44
OUT1A
38 39
28 29
43 44
34 35
32 33
23 24
25 42
36 37
30 31
GND
Continued on next page.
No.A1864-8/25
LV8740V
Continued from preceding page.
Pin No.
Pin
1
VG
2
VM
3
CP2
4
CP1
Equivalent Circuit
4
VREG5
2
3
1
GND
21
VREF
5
VREG5
8
EMO
12
MONI
VREG5
GND
VM
GND
VREG5
GND
Continued on next page.
No.A1864-9/25
LV8740V
Continued from preceding page.
Pin No.
9
Pin
CEM
Equivalent Circuit
VREG5
GND
11
RCHOP
VREG5
GND
No.A1864-10/25
LV8740V
Description of operation
1. Input Pin Function
1-1) Chip enable function
This IC is switched between standby and operating mode by setting the ST pin. In standby mode, the IC is set to
power-save mode and all logic is reset. In addition, the internal regulator circuit and charge pump circuit do not
operate in standby mode.
ST
Mode
Internal regulator
Low or Open
Standby mode
Standby
Charge pump
Standby
High
Operating mode
Operating
Operating
1-2) Drive mode switching pin function
The IC drive mode is switched by setting the DM pin. In STM mode, stepper motor channel 1 can be controlled by the
CLK-IN input. In DCM mode, DC motor channel 2 or stepper motor channel 1 can be controlled by parallel input.
Stepper motor control using parallel input is Full-step or Half-step full torque.
DM
Drive mode
Application
Low or Open
STM mode
Stepper motor channel 1 (CLK-IN)
High
DCM mode
DC motor channel 2 or stepper motor channel 1 (parallel)
2. STM mode (DM = Low or Open)
2-1) STEP pin function
The excitation step progresses by inputting the step signal to the STP pin.
Input
Operating mode
ST
STP
Low
*
Standby mode
High
Excitation step proceeds
High
Excitation step is kept
2-2) Excitation mode setting function
The excitation mode of the stepper motor can be set as follows by setting the MD1 pin and the MD2 pin.
MD1
MD2
Micro-step resolution
(Excitation mode)
Low
Low
High
Low
Initial position
Channel 1
Channel 2
Full step (2 phase excitation)
100%
-100%
Half step (1-2 phase excitation)
100%
0%
Half step (1-2 phase excitation)
100%
0%
Quarter step
100%
0%
full torque
Low
High
High
High
(W1-2 phase excitation)
This is the initial position of each excitation mode in the initial state after power-on and when the counter is reset.
2-3) Positional detection monitor function
The MONI position detection monitoring pin is of an open drain type.
When the excitation position is in the initial position, the MONI output is placed in the ON state.
(Refer to "2-12.Examples of current waveforms in each micro-step mode.")
No.A1864-11/25
LV8740V
2-4)Constant-current control reference voltage setting function
This IC does the PWM fixed current chopping control of the current of the motor by the automatic operation in setting
the output current. The output current in which a fixed current is controlled by the following calculation type is set by
the resistance connected between the voltage and RF-GND being input to the VREF pin.
IOUT=(VREF/5)/RF resistance
*The above-mentioned, set value is an output current of each excitation mode at 100% time.
VREF input voltage attenuation function
ATT1
ATT2
Current setting reference voltage attenuation ratio
Low
Low
100%
High
Low
66.7%
Low
High
50%
High
High
33.3%
The output ammeter calculation type when the attenuation function of the VREF input voltage is used is as follows.
IOUT=(VREF/5)×(Attenuation ratio)/RF resistance
(Example) When VREF = 1.5V, setting current ratio = 100% [(ATT1, ATT2) = (Low, Low)] and RF resistor = 0.22Ω,
the following output current flows :
IOUT = 1.5V/5×100%/0.22Ω=1.36A
Under such a condition, when assuming (ATT1, ATT2) = (High, High).
IOUT = 1.36A×33.3%=453mA
The power saving can be done, and attenuating the output current when the motor energizes maintenance.
2-5) Input Timing
TstepH TstepL
STEP
Tdh
Tds
(md1 step) (step md1)
MD1
Tdh
Tds
(md2 step) (step md2)
MD2
Tdh
Tds
(fr step) (step fr)
FR
TstepH/TstepL : Clock H/L pulse width (min 500ns)
Tds : Data set-up time (min 500ns)
Tdh : Data hold time (min 500ns)
2-6) Blanking period
If, when exercising PWM constant-current chopping control over the motor current, the mode is switched from decay
to charge, the recovery current of the parasitic diode may flow to the current sensing resistance, causing noise to be
carried on the current sensing resistance pin, and this may result in erroneous detection. To prevent this erroneous
detection, a blanking period is provided to prevent the noise occurring during mode switching from being received.
During this period, the mode is not switched from charge to decay even if noise is carried on the current sensing
resistance pin.
This IC's blanking period is fixed at about 1 µs in STM mode (2 µs in DCM mode).
No.A1864-12/25
LV8740V
2-7) Reset function
RST
Operating mode
Low
Normal operation
High
Reset state
RST
RESET
STEP
MONI
1ch output
0%
2ch output
Initial state
When the RST pin is set High, the output excitation position is forced to the initial state, and the MONI output enters
ON a state. When RST is set Low after that, the excitation position proceeds to the next STEP input.
2-8) Output enable function
OE
Operating mode
High
Output OFF
Low
Output ON
OE
Power save mode
STEP
MONI
1ch output
0%
2ch output
Output is high-impedance
When the OE pin is set High, the output is forced OFF and goes to high impedance.
However, the internal logic circuits are operating, so the excitation position proceeds when the STEP signal is input to
the STP pin. Therefore, when OE is returned to Low, the output level conforms to the excitation position proceeded
by the STEP input.
No.A1864-13/25
LV8740V
2-9) Forward/reverse switching function
FR
Operating mode
Low
Clockwise (CW)
High
Counter-clockwise (CCW)
FR
CW mode
CCW mode
CW mode
STEP
Excitation position
(1)
(2)
(3)
(4)
(5)
(6)
(5)
(4)
(3)
(4)
(5)
1ch output
2ch output
The internal D/A converter proceeds by one bit at the rising edge of the input STEP pulse.
In addition, CW and CCW mode are switched by setting the FR pin.
In CW mode, the channel 2 current phase is delayed by 90° relative to the channel 1 current.
In CCW mode, the channel 2 current phase is advanced by 90° relative to the channel 1 current.
2-10) Setting the chopping frequency
For constant-current control, chopping operation is made with the frequency determined by the external resistor
(connected to the RCHOP pin).
The chopping frequency to be set with the resistance connected to the RCHOP pin (pin 11) is as shown below.
Chopping frequency settings (reference data)
100
Fchop – kHz
80
60
40
20
0
0
10
20
30
RCHOP – kΩ
40
50
60
PCA01883
No.A1864-14/25
LV8740V
2-11) Output current vector locus (one step is normalized to 90 degrees)
100
Channel 1 phase current ratio (%)
80
60
40
20
0.0
0.0
40
20
80
60
100
Channel 2 current ratio (%)
Setting current ration in each micro-step mode
STEP
Quarter-step (%)
Channel 1
Half-step (%)
Channel 2
Channel 1
θ0
0
100
θ1
35
90
θ2
70
70
θ3
90
35
θ4
100
0
Half-step full torque (%)
Channel 2
Channel 1
Full-step (%)
Channel 2
Channel 1
0
100
0
100
70
70
100
100
100
0
100
0
100
Channel 2
100
No.A1864-15/25
LV8740V
2-12) Examples of current waveforms in each micro-step mode
Full step (CW mode)
STEP
MONI
(%)
100
l1
0
-100
(%)
100
I2
0
-100
Half step full torque (CW mode)
STEP
MONI
(%)
100
I1
0
-100
(%)
100
I2
0
-100
No.A1864-16/25
LV8740V
Half step (CW mode)
STEP
MONI
(%)
100
I1
0
-100
(%)
100
I2
0
-100
Quarter step (CW mode)
STEP
MONI
(%)
100
I1
0
-100
(%)
100
I2
0
-100
No.A1864-17/25
LV8740V
2-13) Current control operation specification
(Sine wave increasing direction)
STEP
Set current
Set current
Coil current
Forced CHARGE
section
fchop
Current mode CHARGE
SLOW
FAST
CHARGE
SLOW
FAST
(Sine wave decreasing direction)
STEP
Set current
Coil current
Forced CHARGE
section
Set current
fchop
Current mode CHARGE
SLOW
FAST
Forced CHARGE
section
FAST
CHARGE
SLOW
In each current mode, the operation sequence is as described below :
• At rise of chopping frequency, the CHARGE mode begins.(The section in which the CHARGE mode is forced
regardless of the magnitude of the coil current (ICOIL) and set current (IREF) exists for 1/16 of one chopping cycle.)
• The coil current (ICOIL) and set current (IREF) are compared in this forced CHARGE section.
When (ICOIL<IREF) state exists in the forced CHARGE section ;
CHARGE mode up to ICOIL ≥ IREF, then followed by changeover to the SLOW DECAY mode, and finally
by the FAST DECAY mode for the 1/16 portion of one chopping cycle.
When (ICOIL<IREF) state does not exist in the forced CHARGE section;
The FAST DECAY mode begins. The coil current is attenuated in the FAST DECAY mode till one cycle of
chopping is over.
Above operations are repeated. Normally, the SLOW (+FAST) DECAY mode continues in the sine wave increasing
direction, then entering the FAST DECAY mode till the current is attenuated to the set level and followed by the SLOW
DECAY mode.
No.A1864-18/25
LV8740V
3.DCM Mode (DM-High)
3-1) DCM mode output control logic
Parallel input
Output
DC11 (21)
DC12 (22)
Low
High
Mode
OUT1 (2) A
OUT1 (2) B
Low
OFF
OFF
Standby
Low
High
Low
CW (Forward)
Low
High
Low
High
CCW (Reverse)
High
High
Low
Low
Brake
3-2) Reset function
RST
Operating mode
MONI
High or Low
Reset operation not performed
High output
The reset function does not operate in DCM mode. In addition, the MONI output is High, regardless of the RST pin
state.
3-3) Output enable function
OE
Operating mode
High
Output OFF
Low
Output ON
When the OE pin is set High, the output is forced OFF and goes to high impedance. When the OE pin is set Low,
output conforms to the control logic.
3-4) Current limit control time chart
When the current of the motor reaches up to the limit current by setting the current limit, this IC does the short brake
control by the automatic operation so that the current should not increase more than it.
Set current
Current mode
Coil current
Forced CHARGE
section
fchop
Current mode
CHARGE
SLOW
Moreover, the voltage impressed to the terminal VREF can be switched to the setting of four stages by the state of two
input of ATT1 and ATT2.
VREF input voltage attenuation function
ATT1
ATT2
Current setting reference voltage
Low
Low
100%
High
Low
66.7%
Low
High
50%
High
High
33.3%
The output ammeter calculation type when the attenuation function of the VREF input voltage is used is as follows.
IOUT=(VREF/5)×(Attenuation ratio)/RF resistance
(Example) When VREF = 1.5V, setting current ratio = 100% [(ATT1, ATT2) = (Low, Low)] and RF resistor = 0.22Ω,
the following output current flows :
IOUT = 1.5V/5×100%/0.22Ω=1.36A
Under such a condition, when assuming (ATT1, ATT2) = (High, High).
IOUT = 1.36A×33.3%=453mA
No.A1864-19/25
LV8740V
3-5) Examples of current waveform in each micro-step mode when stepper motor parallel input control
Full step (CW mode)
DC11
DC12
DC21
DC22
(%)
100
lOUT1
0
-100
(%)
100
lOUT2
0
-100
Half step full torque (CW mode)
DC11
DC21
DC12
DC22
(%)
100
l1
0
-100
(%)
100
l2
0
-100
No.A1864-20/25
LV8740V
4.Output short-circuit protection circuit
This output short protection circuit that makes the output a standby mode to prevent the thing that IC destroys when
the output is short-circuited by a voltage short and the earth fault, etc. , and turns on the warning output to IC is built
into.
4-1) Output short-circuit protection mode switching function
Output short-circuit protection mode of IC can be switched by the setting of EMM pin.
EMM
State
Low or Open
Latch method
High
Auto reset method
4-2) Latch method
In the latch mode, the output is turned off when the output current exceeds the detection current, and the state is
maintained.
The output short protection circuit starts operating so that IC may detect a short output. When the short-circuit is the
consecutive between internal timers (≈4μs), the output where the short-circuit is first detected is turned off. Even if
the following time (Tcem) of the timer latch is exceeded, the output is turned ON again, and afterwards, when the
short-circuit is detected, all the outputs of correspondence ch side are still switched to the standby mode, and the state
is maintained. This state is released by making it to ST ="L".
Output ON
H bridge
output status
Standby status
Output OFF
Output ON
Suresshu voltage
CEM voltage
Connect
detection status
Connection release
Connection
Internal counter
First counter
biginning
First counter
interruption
First counter
biginning
First counter
end
Second counter
biginning
Second counter
end
4-3) Automatic return method
In the automatic return mode, the output wave type changes into the switching wave type when the output current
exceeds the detection current.
The short-circuit detection circuit operates when a short output is detected as well as the latch method. The output is
switched to the standby mode when the operation of the short-circuit detection circuit exceeds the following time
(Tcem) of the timer latch, and it returns to the turning on mode again after 2ms(TYP). At this time, the
above-mentioned switching mode is repeated when is still in the over current mode until the over current mode is
made clear.
4-4) Abnormal state warning output pin
When IC operates the protection circuit detecting abnormality, the EMO pin has been installed as a terminal that
outputs this abnormality to CPU side. This pin is an open drain output, and if abnormality is detected, the EMO output
becomes (EMO="L") of ON.
EMO pin enters on a state in the following.
• When a voltage short, the earth fault or the load is short-circuited and the output short-circuit protection circuit
operates, the output pin
• When the junction temperature of IC rises, and the overheating protection circuit operates
No.A1864-21/25
LV8740V
4-5) Timer latch time (Tcem)
The time to output OFF when an output short-circuit occurs can be set by the capacitor connected between the CEM
pin and GND. The capacitor (Ccem) value can be determined as follows :
Tcem ≈ C × V/I [sec]
V : Threshold voltage of comparator TYP 1V
I : CEM charge current TYP 10μA
Timer latch : Tcem
5.Thermal shutdown function
The thermal shutdown circuit is included, and the output is turned off when junction temperature Tj exceeds 180°C
and the abnormal state warning output is turned on at the same time.
When the temperature falls hysteresis level, output is driven again (automatic restoration)
The thermal shutdown circuit doesn’t guarantee protection of the set and the destruction prevention of IC, because it
works at the temperature that is higher than rating (Tjmax=150°C) of the junction temperature
TTSD = 180°C (typ)
ΔTSD = 40°C (typ)
6.Charge Pump Circuit
When the ST pin is set High, the charge pump circuit operates and the VG pin voltage is boosted from the VM voltage
to the VM + VREG5 voltage. If the VG pin voltage is not boosted to VM+4V or more, the output pin cannot be turned
on. Therefore it is recommended that the drive of motor is started after the time has passed tONG or more.
ST
VG pin voltage
VM+VREG5
VM+4V
VM
tONG
VG Pin Voltage Schematic View
No.A1864-22/25
LV8740V
Application Circuits
47kΩ
Connect status
detection monitor
100pF
47kΩ
1. Stepper motor driver application circuit example(DM=”L”)
1 VG
OUT1A 44
2 VM
OUT1A 43
3 CP2
PGND1 42
4 CP1
NC 41
5 VREG5
NC 40
VM1 39
7 ATT1
VM1 38
8 EMO
RF1 37
9 CEM
RF1 36
10 EMM
OUT1B 35
11 RCHOP
12 MONI
Position detection
monitor
13 RST
Clock input
Logic input
- +
1.5V
LV8740V
6 ATT2
24V
+ -
0.22Ω
OUT1B 34
OUT2A 33
M
OUT2A 32
14 STP/DC22
RF2 31
15 FR/DC21
RF2 30
16 MD2/DC12
VM2 29
17 MD1/DC11
VM2 28
18 DM
NC 27
19 OE
NC 26
20 ST
PGND2 25
21 VREF
OUT2B 24
22 GND
OUT2B 23
0.22Ω
Each constant setting type in the example of the above-mentioned circuit is as follows.
When setting current ratio = 100%, VREF = 1.5V, the following output current flows :
IOUT = VREF/5/RF resistance
= 1.5V/5×100%/0.22Ω=1.36A
Chopping frequency setting.
62.5kHz (RCHOP=20kΩ)
Time of timer latch when output is short-circuited
Tcem = Ccem * Vtcem/Icem
= 100pF * 1V/10μA = 10μs
No.A1864-23/25
LV8740V
2. DC motor driver application circuit example
47k
Connect status
detection monitor
100pF
1 VG
OUT1A 44
2 VM
OUT1A 43
3 CP2
PGND1 42
4 CP1
NC 41
5 VREG5
NC 40
VM1 39
7 ATT1
VM1 38
8 EMO
RF1 37
9 CEM
RF1 36
10 EMM
OUT1B 35
11 RCHOP
12 MONI
13 RST
Logic input
- +
1.5V
LV8740V
6 ATT2
24V
+ -
M
0.22
OUT1B 34
OUT2A 33
OUT2A 32
14 STP/DC22
RF2 31
15 FR/DC21
RF2 30
16 MD2/DC12
VM2 29
17 MD1/DC11
VM2 28
18 DM
NC 27
19 OE
NC 26
20 ST
PGND2 25
21 VREF
OUT2B 24
22 GND
OUT2B 23
0.22
M
Each constant setting type in the example of the above-mentioned circuit is as follows.
When setting current LIMIT = 100%, VREF = 1.5V, the following output current flows :
Ilimit = VREF/5/RF resistance
= 1.5V/5×100%/0.22Ω=1.36A
Chopping frequency setting.
62.5kHz (RCHOP=20kΩ)
Time of timer latch when output is short-circuited
Tcem = Ccem * Vtcem/Icem
= 100pF * 1V/10μA = 10μs
No.A1864-24/25
LV8740V
ORDERING INFORMATION
Device
LV8740V-TLM-E
Package
SSOP44J (275mil)
(Pb-Free)
LV8740V-MPB-E
SSOP44J (275mil)
(Pb-Free)
Shipping (Qty / Packing)
2000 / Tape & Reel
30 / Fan-Fold
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PS No.A1864-25/25