LV8740V [ONSEMI]
PWM Current Control Stepper Motor Driver;
| 型号： | LV8740V |
| 厂家： | 
ONSEMI |
| 描述： | PWM Current Control Stepper Motor Driver |
| 文件： | 总25页 (文件大小：368K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Ordering number : ENA1864A
LV8740V
Monolithic Linear IC
http://onsemi.com
PWM Current Control Stepper
Motor Driver
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, I = 2.5A)
O
• 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
V
Supply voltage 1
V
max
VM , VM1 , VM2
38
3.0
2.5
M
Output peak current
Output current
I
peak
max
tw ≤ 10ms, duty 20%, Each 1ch
A
O
I
Each 1ch
A
O
Logic input voltage
V
ST , OE , DM , MD1/DC11 , MD2/DC12 ,
-0.3 to +6.0
V
IN
/V
FR/DC21 , STP/DC22 , RST , EMM , ATT1 , ATT2
MONI/EMO input voltage
Allowable power dissipation
Operating temperature
Storage temperature
V
-0.3 to +6.0
3.45
V
MONI EMO
Pd max
*
W
°C
°C
Topr
Tstg
-30 to +85
-55 to +150
* 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
Supply voltage range
Logic input voltage
Symbol
Conditions
Ratings
Unit
V
V
VM , VM1 , VM2
9 to 35
0 to 5.5
M
V
ST , OE , DM , MD1/DC11 , MD2/DC12 ,
FR/DC21 , STP/DC22 , RST , EMM , ATT1 ,
ATT2
V
IN
VREF input voltage range
VREF
0 to 3.0
V
Electrical Characteristics at Ta = 25°C, V = 24V, VREF = 1.5V
M
Ratings
typ
Parameter
Symbol
Conditions
Unit
min
max
250
5
Standby mode current drain
Current drain
IMstn
IM
ST = ”L” , I(VM)+I(VM1)+I(VM2)
180
3
μA
ST = ”H”, OE = ”L”, no load
I(VM)+I(VM1)+I(VM2)
mA
VREG5 output voltage
Thermal shutdown temperature
Thermal hysteresis width
Motor Driver
Vreg5
TSD
I
=-1mA
4.7
5.0
180
40
5.3
V
O
Design guarantee
Design guarantee
150
210
°C
°C
ΔTSD
Output on-resistance
Ronu
Rond
I
I
= 2.5A, Upper-side on resistance
= 2.5A, Lower-side on resistance
0.3
0.2
0.4
0.25
50
Ω
Ω
O
O
Output leakage current
Diode forward voltage
ST pin input current
I
leak
VM=35V
μA
V
O
VD
ID = -2.5A
1.1
8
1.3
15
I
L
V
V
= 0.8V
= 5V
3
48
3
μA
μA
μA
ST
IN
I
H
80
8
112
15
ST
IN
Logic pin input current
(other ST pin)
I
L
OE , DM , MD1/DC11 , MD2/DC12 ,
IN
FR/DC21 , STP/DC22 , RST , EMM , ATT1 ,
ATT2 , V = 0.8V
IN
I
H
h
V
= 5V
30
2.0
0
50
70
5.5
0.8
μA
V
IN
IN
Logic input voltage
High
Low
V
ST , OE , DM , MD1/DC11 , MD2/DC12 ,
FR/DC21 , STP/DC22 , RST , EMM , ATT1 ,
ATT2
IN
V
l
V
IN
Current setting
comparator
Quarter
step
Vtdac0_W
Step 0(When initialized : channel 1
comparator level)
0.290
0.300
0.310
V
threshold voltage
(Current step
switch)
resolution
Vtdac1_W
Vtdac2_W
Vtdac3_W
Vtdac0_H
Step 1 (Initial state+1)
0.260
0.200
0.095
0.290
0.270
0.210
0.105
0.300
0.280
0.220
0.115
0.310
V
V
V
V
Step 2 (Initial state+2)
Step 3 (Initial state+3)
Half step
resolution
Step 0 (When initialized: channel 1
comparator level)
Vtdac2_H
Step 2 (Initial state+1)
0.200
0.290
0.210
0.300
0.220
0.310
V
V
Half step
Vtdac0_HF
Step 0 (Initial state, channel 1 comparator
level)
resolution
(full torque)
Vtdac2_HF
Vtdac2_F
Step 2 (Initial state+1)
0.290
0.290
0.300
0.300
0.310
0.310
V
V
Full step
Step 2
resolution
Current setting comparator
threshold voltage
Vtatt00
Vtatt01
Vtatt10
Vtatt11
Fchop
Iref
ATT1=L, ATT2=L
ATT1=H, ATT2=L
ATT1=L, ATT2=H
ATT1=H, ATT2=H
RCHOP = 20kΩ
VREF = 1.5V
0.290
0.190
0.140
0.090
45
0.300
0.200
0.150
0.100
62.5
0.310
0.210
0.160
0.110
75
V
V
(Current attenuation rate switch)
V
V
Chopping frequency
VREF pin input current
MONI pin saturation voltage
Charge pump
kHz
μA
mV
-0.5
Vsatmon
I
=1mA
50
100
MONI
VG output voltage
Rise time
VG
28
90
28.7
29.8
0.5
V
tONG
VG = 0.1μF , Between CP1-CP2 0.1uF
ST=”H” → VG=VM+4V
ms
Oscillator frequency
Fosc
RCHOP = 20kΩ
125
150
kHz
Continued on next page.
No.A1864-2/25
LV8740V
Continued from preceding page.
Ratings
typ
Parameter
Symbol
Conditions
Unit
min
max
Output short-circuit protection
EMO pin saturation voltage
CEM pin charge current
Vsatemo
Icem
Iemo = 1mA
Vcem=0V
50
100
mV
μA
V
7
10
13
CEM pin threshold voltage
Vtcem
0.8
1.0
1.2
Pin Assignment
VG
VM
1
2
3
4
5
6
7
8
9
44 OUT1A
43 OUT1A
42 PGND1
41 NC
CP2
CP1
VREG5
ATT2
ATT1
EMO
CEM
40 NC
39 VM1
38 VM1
37 RF1
36 RF1
EMM 10
RCHOP 11
MONI 12
35 OUT1B
34 OUT1B
33 OUT2A
32 OUT2A
31 RF2
LV8740V
RST 13
STP/DC22 14
FR/DC21 15
MD2/DC12 16
MD1/DC11 17
DM 18
30 RF2
29 VM2
28 VM2
27 NC
OE 19
26 NC
ST 20
25 PGND2
24 OUT2B
23 OUT2B
VREF
GND
21
22
Top view
No.A1864-3/25
LV8740V
Package Dimensions
unit : mm (typ)
3285B
TOP VIEW
SIDE VIEW
BOTTOM VIEW
15.0
44
(7.8)
1
2
0.2
0.65
0.22
(0.68)
SIDE VIEW
SSOP44J(275mil)
Pd max - Ta
6.0
5.0
4.0
Four-layer circuit board 1*1
5.50
Four-layer circuit board 2*2
3.80
2.65
3.45
Two-layer circuit board 1*1
3.0
2.0
2.86
Two-layer circuit board 2*2
1.98
1.79
1.38
1.0
0
*1 With components mounted on the exposed die-pad board
*2 With no components mounted on the exposed die-pad board
10
70
30
90
50
Ambient temperature, Ta -
C
No.A1864-4/25
LV8740V
Substrate Specifications (Substrate recommended for operation of LV8740V)
Size
Material
: 90mm × 90mm × 1.6mm
: 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
LV8740V
Block Diagram
O u t p u t p r e a m p l i f i e r s t a g e
O u t p u t p r e a m p l i f i e r s t a g e
O u t p u t p r e a m p l i f i e r s t a g e
O u t p u t p r e a m p l i f i e r s t a g e
No.A1864-6/25
LV8740V
Pin Functions
Pin No.
Pin name
VG
VM
Description
1
2
Charge pump capacitor connection pin
Motor power supply connection pin
3
CP2
Charge pump capacitor connection pin
Charge pump capacitor connection pin
Internal power supply capacitor connection pin
Motor holding current switching pin
4
CP1
5
VREG5
ATT2
6
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
Over current mode switching pin
10
EMM
11
RCHOP
MONI
RST
Chopping frequency setting resistor connection pin
Position detection monitor pin
12
13
Reset signal input pin
14
STP/DC22
FR/DC21
MD2/DC12
MD1/DC11
DM
STM STEP signal input pin/DCM2 output control input pin
STM forward/reverse rotation signal input pin/DCM2 output control input pin
STM excitation mode switching pin/DCM1 output control input pin
STM excitation mode switching pin/DCM1 output control input pin
Drive mode (STM/DCM) switching pin
Output enable signal input pin
15
16
17
18
19
OE
20
ST
Chip enable pin
21
VREF
GND
Constant current control reference voltage input pin
Signal system ground
22
23, 24
25
OUT2B
PGND2
VM2
Channel 2 OUTB output pin
Channel 2 Power system ground
28, 29
30, 31
32, 33
34, 35
36, 37
38, 39
42
Channel 2 motor power supply connection pin
Channel 2 current-sense resistor connection pin
Channel 2 OUTA output pin
RF2
OUT2A
OUT1B
RF1
Channel 1 OUTB output pin
Channel 1 current-sense resistor connection pin
Channel 1 motor power supply pin
VM1
PGND1
OUT1A
NC
Channel 1 Power system ground
43, 44
Channel 1 OUTA output pin
26, 27
40, 41
No Connection
(No internal connection to the IC)
No.A1864-7/25
LV8740V
Equivalent Circuits
Pin No.
Pin
Equivalent Circuit
6
ATT2
ATT1
EMM
RST
VREG5
7
10
13
14
15
16
17
18
19
STP/DC22
FR/DC21
MD2/DC12
MD1/DC11
DM
OE
GND
VREG5
20
ST
GND
23, 24
25
OUT2B
PGND2
VM2
39
38
28 29
28, 29
30, 31
32, 33
34, 35
36, 37
38, 39
42
RF2
OUT2A
OUT1B
RF1
VM1
PGND1
OUT1A
43 44
32 33
34 35
23 24
43, 44
25 42
37
31
36
30
GND
Continued on next page.
No.A1864-8/25
LV8740V
Continued from preceding page.
Pin No.
Pin
Equivalent Circuit
2
1
2
3
4
VG
4
3
1
VREG5
VM
CP2
CP1
GND
VREG5
21
VREF
GND
5
VREG5
VM
GND
8
EMO
VREG5
12
MONI
GND
Continued on next page.
No.A1864-9/25
LV8740V
Continued from preceding page.
Pin No.
9
Pin
Equivalent Circuit
CEM
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
Low or Open
High
Mode
Internal regulator
Charge pump
Standby mode
Operating mode
Standby
Standby
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
Low or Open
High
Drive mode
STM mode
DCM mode
Application
Stepper motor channel 1 (CLK-IN)
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
High
Standby mode
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)
Initial position
Channel 1
100%
Channel 2
-100%
0%
Low
Low
Low
Full step (2 phase excitation)
High
Half step (1-2 phase excitation)
full torque
100%
Low
High
High
Half step (1-2 phase excitation)
100%
100%
0%
0%
High
Quarter step
(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.
I
=(VREF/5)/RF resistance
OUT
*The above-mentioned, set value is an output current of each excitation mode at 100% time.
VREF input voltage attenuation function
ATT1
Low
ATT2
Low
Current setting reference voltage attenuation ratio
100%
66.7%
50%
High
Low
Low
High
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 :
I
= 1.5V/5×100%/0.22Ω=1.36A
OUT
Under such a condition, when assuming (ATT1, ATT2) = (High, High).
= 1.36A×33.3%=453mA
I
OUT
The power saving can be done, and attenuating the output current when the motor energizes maintenance.
2-5) Input Timing
TstepL
TstepH
STEP
MD1
MD2
Tds
Tdh
(md1 step) (step md1)
Tds
Tdh
(md2 step) (step md2)
Tdh
(step fr)
Tds
(fr step)
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
Normal operation
Reset state
Low
High
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
High
Low
Operating mode
Output OFF
Output ON
OE
Power save mode
STEP
MONI
1ch output
2ch output
0%
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
High
Clockwise (CW)
Counter-clockwise (CCW)
CW mode
FR
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
80
60
40
20
0
0
10
20
30
40
50
60
PCA01883
RCHOP – kΩ
No.A1864-14/25
LV8740V
2-11) Output current vector locus (one step is normalized to 90 degrees)
100
80
60
40
20
0.0
40
Channel 2 current ratio (%)
80
0.0
20
60
100
Setting current ration in each micro-step mode
STEP
Quarter-step (%)
Half-step (%)
Half-step full torque (%)
Full-step (%)
Channel 1 Channel 2
Channel 1 Channel 2
Channel 1 Channel 2
Channel 1
Channel 2
100
θ0
θ1
θ2
θ3
θ4
0
35
100
90
70
35
0
0
70
100
70
0
0
70
100
100
100
0
100
100
90
100
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
I2
0
-100
(%)
100
0
-100
Half step full torque (CW mode)
STEP
MONI
(%)
100
I1
I2
0
-100
(%)
100
0
-100
No.A1864-16/25
LV8740V
Half step (CW mode)
STEP
MONI
(%)
100
I1
I2
0
-100
(%)
100
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 FAST
section
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
Mode
DC11 (21)
Low
DC12 (22)
Low
OUT1 (2) A
OFF
OUT1 (2) B
OFF
Standby
CW (Forward)
CCW (Reverse)
Brake
High
Low
High
Low
Low
High
Low
High
High
High
Low
Low
3-2) Reset function
RST
Operating mode
Reset operation not performed
MONI
High or Low
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
High
Low
Operating mode
Output OFF
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%
66.7%
50%
High
Low
Low
High
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 :
I
= 1.5V/5×100%/0.22Ω=1.36A
OUT
Under such a condition, when assuming (ATT1, ATT2) = (High, High).
= 1.36A×33.3%=453mA
I
OUT
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
l
l
1
0
OUT
OUT
-100
(%)
100
2
0
-100
Half step full torque (CW mode)
DC11
DC21
DC12
DC22
(%)
100
l1
l2
0
-100
(%)
100
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
Low or Open
High
State
Latch method
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
Conn-
ection
release
Connection
Internal counter
First counter
biginning
First counter First counter
interruption biginning
Second counter
biginning
Second counter
end
First 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 :
Timer latch : Tcem
Tcem ≈ C × V/I [sec]
V : Threshold voltage of comparator TYP 1V
I : CEM charge current TYP 10μA
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
1. Stepper motor driver application circuit example(DM=”L”)
1
2
VG
OUT1A 44
OUT1A 43
PGND1 42
VM
CP2
3
4
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
CP1
NC
NC
5
VREG5
ATT2
24V
+ -
6
VM1
47kΩ
7
ATT1
VM1
Connect status
detection monitor
8
EMO
RF1
9
CEM
RF1
0.22Ω
100pF
10
11
12
13
14
15
16
17
18
19
20
21
22
EMM
OUT1B
OUT1B
OUT2A
OUT2A
RF2
RCHOP
MONI
RST
Position detection
monitor
M
Clock input
Logic input
STP/DC22
FR/DC21
MD2/DC12
MD1/DC11
DM
RF2
0.22Ω
VM2
VM2
NC
OE
NC
ST
PGND2
OUT2B
OUT2B
- +
1.5V
VREF
GND
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 :
I
= VREF/5/RF resistance
OUT
= 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
1
2
VG
OUT1A 44
VM
OUT1A 43
PGND1 42
3
CP2
4
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
CP1
NC
NC
5
VREG5
ATT2
24V
+
-
6
M
VM1
47k
7
ATT1
VM1
Connect status
detection monitor
8
EMO
RF1
9
CEM
RF1
0.22
100pF
10
11
12
13
14
15
16
17
18
19
20
21
22
EMM
OUT1B
OUT1B
OUT2A
OUT2A
RF2
RCHOP
MONI
RST
STP/DC22
FR/DC21
MD2/DC12
MD1/DC11
DM
RF2
0.22
VM2
M
Logic input
VM2
NC
OE
NC
ST
PGND2
OUT2B
OUT2B
-
+
VREF
GND
1.5V
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
Package
SSOP44J (275mil)
(Pb-Free)
Shipping (Qty / Packing)
2000 / Tape & Reel
LV8740V-TLM-E
SSOP44J (275mil)
(Pb-Free)
LV8740V-MPB-E
30 / Fan-Fold
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performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical
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PS No.A1864-25/25
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