Ordering number : ENA1824B
LV8734V
Monolithic Linear IC
PWM Constant-Current Control
Stepper Motor Driver
http://onsemi.com
Overview
The LV8734V is a 2-channel H-bridge driver IC that can switch a stepper motor driver, which supports micro-step
drive with 1/8-step resolution, and two channels of a brushed 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.
• BiCDMOS process IC
• Low on resistance (upper side : 0.48Ω ; lower side : 0.32Ω ; total of upper and lower : 0.8Ω ; Ta = 25°C, IO = 1.5A)
• Micro-step mode can be set to Full-step, Half-step, Quarter-step , or 1/8-step
• Excitation step proceeds only by step signal input
• Motor current selectable in four steps
• Output short-circuit protection circuit (selectable from latch-type or auto-reset-type) incorporated
• Unusual condition warning output pins
• Built-in thermal shutdown circuit
• No control power supply required
Specifications
Absolute Maximum Ratings at Ta = 25°C
Parameter
Symbol
Conditions
Supply voltage
VM max
VM, VM1, VM2
Output peak current
IO peak
tw ≤ 10ms, duty 20%, per 1ch
Output current
IO max
Logic input voltage
VIN max
Per 1ch
ATT1, ATT2, EMM, RST/BLK, STEP/DC22,
FR/DC21, MD2/DC12, MD1/DC11, DM,
OE/CMK, ST
MONI/EMO input voltage
Vmo/Vemo
Allowable power dissipation
Pd max
Operating temperature
Storage temperature
Ratings
Unit
36
V
1.75
A
1.5
A
-0.3 to +6
V
-0.3 to +6
V
3.25
W
Topr
-40 to +85
°C
Tstg
-55 to +150
°C
*
* Specified circuit board : 90.0mm×90.0mm×1.6mm, glass epoxy 2-layer board, with backside 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 26 of this data sheet.
Semiconductor Components Industries, LLC, 2013
June, 2013
61913NK 20130402-S00002 No.A1824-1/26
LV8734V
Allowable Operating Ratings at Ta = 25°C
Parameter
Supply voltage range
Symbol
VM
Logic input voltage
VIN
VREF input voltage range
VREF
Conditions
Ratings
VM, VM1, VM2
ATT1, ATT2, EMM, RST/BLK, STEP/DC22, FR/DC21,
MD2/DC12, MD1/DC11, DM, OE/CMK, ST
Unit
9 to 32
V
0 to 5.5
V
0 to 3
V
Electrical Characteristics at Ta = 25°C, VM = 24V, VREF = 1.5V
Ratings
Parameter
Symbol
Conditions
Unit
min
typ
max
Standby mode current drain
IMst
ST = “L” , I(VM)+I(VM1)+I(VM2)
100
400
μA
Current drain
IM
ST = “H”, OE = “L”, with no load
3.2
5
mA
VREG5 output voltage
Vreg5
IO = -1mA
4.5
5
5.5
V
Thermal shutdown temperature
TSD
Design guarantee
150
180
200
°C
Thermal hysteresis width
ΔTSD
Design guarantee
I(VM)+I(VM1)+I(VM2)
°C
40
Motor driver
Output on resistance
Output leakage current
Diode forward voltage
Logic input voltage
IO = 1.5A, Upper-side on resistance
0.48
0.63
IO = 1.5A, Lower-side on resistance
0.32
0.42
Ω
50
μA
IOleak
VD
High
VINH
Low
VINL
Logic pin input current
IINL
OE/CMK pin current LIMIT mask
ID = -1.5A
ATT1, ATT2, EMM, RST/BLK, STEP/DC22,
FR/DC21, MD2/DC12, MD1/DC11, DM,
OE/CMK, ST
ATT1, ATT2, EMM, RST/BLK, STEP/DC22,
1.4
V
2.0
1.2
5.5
V
0
0.8
V
4
8
12
μA
30
50
70
μA
4
8
12
μA
FR/DC21, MD2/DC12, MD1/DC11, DM, ST,
Except the OE/CMK pin
OE / CMK pin input current
Ω
Ronu
Rond
IINH
VIN = 0.8V
VIN = 5V
ICMKL
DM = “L”, OE/CMK = 0.8V
ICMKH
DM = “L”, OE/CMK = 5V
30
50
70
μA
ICMK
DM = “H”, OE/CMK = 0V
-32
-25
-18
μA
VtCMK
DM = “H”
1.2
1.5
1.8
V
Vtdac0_2W
Step 0 (When initialized : channel 1
0.291
0.3
0.309
V
threshold voltage.
Current setting
1/8 step
comparator
resolution
comparator level)
threshold
Vtdac1_2W
Step 1 (Initial state+1)
0.285
0.294
0.303
V
voltage
Vtdac2_2W
Step 2 (Initial state+2)
0.267
0.276
0.285
V
Vtdac3_2W
Step 3 (Initial state+3)
0.240
0.249
0.258
V
Vtdac4_2W
Step 4 (Initial state+4)
0.201
0.21
0.219
V
Vtdac5_2W
Step 5 (Initial state+5)
0.157
0.165
0.173
V
Vtdac6_2W
Step 6 (Initial state+6)
0.107
0.114
0.121
V
Vtdac7_2W
Step 7 (Initial state+7)
0.053
0.06
0.067
V
Vtdac0_W
Step 0 (When initialized : channel 1
0.291
0.3
0.309
V
0.267
0.276
0.285
V
(current step
switching)
Quarter step
resolution
Half step
comparator level)
Vtdac2_W
Step 2 (Initial state+1)
Vtdac4_W
Step 4 (Initial state+2)
0.201
0.21
0.219
V
Vtdac6_W
Step 6 (Initial state+3)
0.107
0.114
0.121
V
Vtdac0_H
Step 0 (When initialized : channel 1
0.291
0.3
0.309
V
resolution
comparator level)
Vtdac4_H
Step 4 (Initial state+1)
0.201
0.21
0.219
V
Vtdac4_F
Step 4' (When initialized : channel 1
0.291
0.3
0.309
V
Current setting comparator
Vtatt00
ATT1 = L, ATT2 = L
0.291
0.3
0.309
V
threshold voltage
Vtatt01
ATT1 = H, ATT2 = L
0.232
0.24
0.248
V
Vtatt10
ATT1 = L, ATT2 = H
0.143
0.15
0.157
V
Vtatt11
ATT1 = H, ATT2 = H
0.053
0.06
0.067
V
Full step
resolution
(current attenuation rate switching)
comparator level)
Continued on next page.
No.A1824-2/26
LV8734V
Continued from preceding page.
Ratings
Parameter
Symbol
Conditions
Unit
min
Chopping frequency
Fchop
CHOP pin charge/discharge current
Ichop
Chopping oscillation circuit
Cchop = 200pF
typ
max
40
50
60
kHz
7
10
13
μA
Vtup
0.8
1
1.2
V
threshold voltage
Vtdown
0.4
0.5
0.6
V
VREF pin input current
Iref
VREF = 1.5V
MONI pin saturation voltage
Vsatmon
Imoni = 1mA
μA
-0.5
400
mV
28.7
29.8
V
200
500
μS
90
125
150
kHz
400
mV
7
10
13
μA
0.8
1
1.2
V
Charge pump
VG output voltage
VG
Rise time
tONG
28
VG = 0.1μF, 0.1μF between CP1-CP2
ST= “H” → VG=VM+4V
Oscillator frequency
Fosc
Output short-circuit protection
EMO pin saturation voltage
Vsatemo
CEM pin charge current
Icem
CEM pin threshold voltage
Vtcem
Iemo = 1mA
Package Dimensions
unit : mm (typ)
3333A
TOP VIEW
SIDE VIEW
BOTTOM VIEW
15.0
44
23
(3.5)
0.5
5.6
7.6
(4.7)
0.22
22
0.2
1.7 MAX
0.65
SIDE VIEW
0.05 (1.5)
1
(0.68)
SSOP44K(275mil)
No.A1824-3/26
LV8734V
Pd max - Ta
4.0
Allowable power dissipation, Pd max - W
Four-layer circuit board 1 * 1
3.25
3.0
Four-layer circuit board 2 * 2
2.20
2.0
1.69
1.14
1.0
*1 With components mounted on the exposed die-pad board
*2 With no components mounted on the exposed die-pad board
0
0
20
40
60
80
100
Substrate Specifications (Substrate recommended for operation of LV8734V)
Size
: 90mm × 90mm × 1.6mm (two-layer substrate [2S0P])
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.A1824-4/26
LV8734V
Pin Assignment
VG 1
44 OUT1A
VM 2
43 OUT1A
CP2 3
42 PGND
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
CHOP 11
34 OUT1B
LV8734V
MONI 12
33 OUT2A
RST/BLK 13
32 OUT2A
STEP/DC22 14
31 RF2
FR/DC21 15
30 RF2
MD2/DC12 16
29 VM2
MD1/DC11 17
28 VM2
DM 18
27 NC
OE/CMK 19
26 NC
ST 20
25 PGND
VREF 21
24 OUT2B
GND 22
23 OUT2B
Top view
No.A1824-5/26
MONI
PGND
VM
GND
VREF
VREG5
+
-
LVS
TSD
+
-
CHOP
Oscillation
circuit
Regulator
ATT2
Attenuator
(4 levels
selectable)
ST ATT1
Charge pump
Output preamplifier stage
RF1
OUT1B VM1
MD1/
DC11
VM2 OUT2A
Output control logic
+
RF2
Current
Limit Mask
Current
selection
(2W1-2/
W1-2/1-2/2)
OUT2B
MD2/ FR/ STEP/ RST/ OE/ DM EMM
DC12 DC21 DC22 BLK CMK
+
Current
selection
(2W1-2/
W1-2/1-2/2)
OUT1A
Output preamplifier stage
VG
Output preamplifier stage
CP1
Output preamplifier stage
CP2
CEM
EMO
LV8734V
Block Diagram
No.A1824-6/26
LV8734V
Pin Functions
Pin No.
Pin Name
Pin Function
6
ATT2
Motor holding current switching pin.
7
ATT1
Motor holding current switching pin.
10
EMM
Output short-circuit protection mode
Equivalent Circuit
VREG5
switching pin.
13
RST/BLK
14
STEP/DC22
15
FR/DC21
RESET input pin (STM) / Blanking time
switching pin (DCM).
STEP signal input pin (STM) / Channel 2
output control input pin 2 (DCM).
10kΩ
CW / CCW signal input pin (STM) /
Channel 2 output control input pin 1
(DCM).
16
MD2/DC12
Excitation mode switching pin 2 (STM) /
100kΩ
Channel 1 output control input pin 2
(DCM).
17
MD1/DC11
Excitation mode switching pin 1 (STM) /
GND
Channel 1 output control input pin 1
(DCM).
18
DM
Drive mode (STM/DCM) switching pin.
20
ST
Chip enable pin.
VREG5
20kΩ
10kΩ
80kΩ
GND
23, 24
OUT2B
Channel 2 OUTB output pin.
25, 42
PGND
Power system ground.
28, 29
VM2
Channel 2 motor power supply
30, 31
RF2
32, 33
OUT2A
Channel 2 OUTA output pin.
34, 35
OUT1B
Channel 1 OUTB output pin.
36, 37
RF1
Channel 1 current-sense resistor
38, 39
VM1
Channel 1 motor power supply pin.
43, 44
OUT1A
Channel 1 OUTA output pin.
38 39
28 29
connection pin.
Channel 2 current-sense resistor
connection pin.
34 35
23 24
43 44
32 33
connection pin.
10kΩ
500Ω
25 42
500Ω
36 37
30 31
GND
Continued on next page.
No.A1824-7/26
LV8734V
Continued from preceding page.
Pin No.
Pin Name
Pin Function
1
VG
Charge pump capacitor connection pin.
2
VM
Motor power supply connection pin.
3
CP2
Charge pump capacitor connection pin.
4
CP1
Charge pump capacitor connection pin.
Equivalent Circuit
2
4
3
1
VREG5
100Ω
GND
21
VREF
Constant current control reference
voltage input pin.
VREG5
500Ω
GND
5
VREG5
Internal power supply capacitor
connection pin.
VM
2kΩ
78kΩ
26kΩ
GND
8
EMO
Output short-circuit state warning output
pin.
12
MONI
VREG5
Position detection monitor pin.
GND
Continued on next page.
No.A1824-8/26
LV8734V
Continued from preceding page.
Pin No.
9
Pin Name
CEM
Pin Function
Pin to connect the output short-circuit
Equivalent Circuit
VREG5
state detection time setting capacitor.
GND
11
CHOP
Chopping frequency setting capacitor
connection pin.
VREG5
500Ω
500Ω
GND
19
OE/CMK
Output enable signal input pin(STM) /
Set capacitor connection pin of time of
VREG5
current LIMIT mask(DCM).
GND
22
26, 27
40, 41
GND
NC
Ground.
No Connection
(No internal connection to the IC)
No.A1824-9/26
LV8734V
Description of operation
1.Input Pin Function
Each input terminal has the function to prevent the flow of the current from an input to a power supply.
Therefore, even if a power supply (VM) is turned off in the state that applied voltage to an input terminal,
the electric current does not flow into the power supply.
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
Charge pump
Low or Open
Standby mode
Standby
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
Input
Operating mode
ST
STP
Low
*
Standby mode
High
Excitation step proceeds
High
Excitation step is kept
2-2) Excitation mode setting function
MD1
MD2
Micro-step resolution
(Excitation mode)
Low
Initial position
Channel 1
Channel 2
Low
Full step(2 phase excitation)
100%
-100%
High
Low
Half step(-2 phase excitation)
100%
0%
Low
High
Quarter step
100%
0%
100%
0%
(W1-2 phase excitation)
High
High
1/8 step(2W1-2 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) Position detection monitoring 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.A1824-10/26
LV8734V
2-4) Setting constant-current control reference current
This IC is designed to automatically exercise PWM constant-current chopping control for the motor current by setting
the output current. Based on the voltage input to the VREF pin and the resistance connected between RF and GND,
the output current that is subject to the constant-current control is set using the calculation formula below :
IOUT = (VREF/5)/RF resistance
* The above setting is the output current at 100% of each excitation mode.
The voltage input to the VREF pin can be switched to four-step settings depending on the statuses of the two inputs,
ATT1 and ATT2. This is effective for reducing power consumption when motor holding current is supplied.
Attenuation function for VREF input voltage
ATT1
ATT2
Current setting reference voltage attenuation ratio
Low
Low
100%
High
Low
80%
Low
High
50%
High
High
20%
The formula used to calculate the output current when using the function for attenuating the VREF input voltage is
given below.
IOUT = (VREF/5) × (attenuation ratio)/RF resistance
Example : At VREF of 1.5V, a reference voltage setting of 100% [(ATT1, ATT2) = (L, L)] and an RF resistance of
0.5Ω, the output current is set as shown below.
IOUT = 1.5V/5 × 100%/0.5Ω = 0.6A
If, in this state, (ATT1, ATT2) is set to (H, H), IOUT will be as follows :
IOUT = 0.6A × 20% = 120mA
In this way, the output current is attenuated when the motor holding current is supplied so that power can
be conserved.
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 time
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 time is provided to prevent the noise occurring during mode switching from being received.
During this time, the mode is not switched from charge to decay even if noise is carried on the current sensing
resistance pin.
In the stepper motor driver mode (DM = Low or Open) of this IC, the blanking time is fixed at approximately 1μs.
In the DC motor driver mode (DM = High), the blanking time can be switched to one of two levels using the
RST/BLK pin. (Refer to "Blanking time switching function.")
No.A1824-11/26
LV8734V
2-7) Reset function
(Only the STM mode. : It change the BLK terminal at DCM mode. It operates as a switch function of the blanking time.
Refer to (Blanking time switching 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 to High, the excitation position of the output is forcibly set to the initial state, and the MONI
output is placed in the ON state. When RST is then set to Low, the excitation position is advanced by the next STEP
input.
2-8) Output enable function
(Only the STM mode. : It change the CMK terminal at DCM mode. It operates as current LIMIT mask function. Refer to (Current
limit reference voltage setting function))
OE
Operating mode
Low
Output ON
High
Output OFF
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.
Therefore, when OE is returned to Low, the output level conforms to the excitation position proceeded by the STEP
input.
No.A1824-12/26
LV8734V
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) Chopping frequency setting
For constant-current control, this IC performs chopping operations at the frequency determined by the capacitor
(Cchop) connected between the CHOP pin and GND.
The chopping frequency is set as shown below by the capacitor (Cchop) connected between the CHOP pin and GND.
Fchop = Ichop/ (Cchop × Vtchop × 2) (Hz)
Ichop : Capacitor charge/discharge current, typ 10μA
Vtchop : Charge/discharge hysteresis voltage (Vtup-Vtdown), typ 0.5V
For instance, when Cchop is 200pF, the chopping frequency will be as follows :
Fchop = 10μA/ (200pF × 0.5V × 2) = 50kHz
No.A1824-13/26
LV8734V
2-11) Output current vector locus (one step is normalized to 90 degrees)
100.0
θ0
θ4' (2-phase)
θ1
θ2
Channel 1 phase current ratio (%)
θ3
θ4
66.7
θ5
θ6
33.3
θ7
θ8
0.0
0.0
33.3
66.7
100.0
Channel 2 current ratio (%)
Setting current ration in each micro-step mode
STEP
1/8 step (%)
Channel 1
Quarter step (%)
Channel 2
Channel 1
θ0
100
0
θ1
98
20
θ2
92
38
θ3
83
55
θ4
70
70
θ5
55
83
θ6
38
92
θ7
20
98
θ8
0
100
Half step (%)
Channel 2
Channel 1
100
0
92
38
70
70
38
92
0
100
Full step (%)
Channel 2
Channel 1
100
0
70
70
0
100
100
Channel 2
100
No.A1824-14/26
LV8734V
2-12) Examples of current waveform in each micro-step mode
Full step (CW mode)
STEP
MONI
(%)
100
l1
0
-100
(%)
100
I2
0
-100
Half step (CW mode)
STEP
MONI
(%)
100
I1
0
-100
(%)
100
I2
0
-100
No.A1824-15/26
LV8734V
Quarter step (CW mode)
STEP
MONI
(%)
100
I1
0
-100
(%)
100
I2
0
-100
1/8 step (CW mode)
STEP
MONI
(%)
100
50
I1
0
-50
-100
(%)
100
50
I2
0
-50
-100
No.A1824-16/26
LV8734V
2-13) Current control operation specification
(Sine wave increasing direction)
STEP
Set current
Set current
Coil current
Forced CHARGE
section
Current mode CHARGE
SLOW
FAST
CHARGE
SLOW
FAST
(Sine wave decreasing direction)
STEP
Set current
Coil current
Forced CHARGE
section
Current mode CHARGE
SLOW
FAST
Set current
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. (In the time defined as the “blanking time,” the CHARGE
mode is forced regardless of the magnitude of the coil current (ICOIL) and set current (IREF).)
• The coil current (ICOIL) and set current (IREF) are compared in this blanking time.
When (ICOIL < IREF) state exists ;
The CHARGE mode up to ICOIL ≥ IREF, then followed by changeover to the SLOW DECAY mode, and
finally by the FAST DECAY mode for approximately 1μs.
When (ICOIL < IREF) state does not exist ;
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.A1824-17/26
LV8734V
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) Blanking time switching function
(Only the DCM mode. : It change the RST terminal at STM mode. It operates as RESET function. Refer to (reset function))
BLK
Blanking time
Low
2μs
High
3μs
3-3) Current limit reference voltage setting function
By setting a current limit, this IC automatically exercises short braking control to ensure that when the motor current
has reached this limit, the current will not exceed it.
(Current limit control time chart)
Set current
Current mode
Coil current
Forced CHARGE
section
fchop
Current mode
CHARGE
SLOW
The limit current is set as calculated on the basis of the voltage input to the VREF pin and the resistance between the
RF pin and GND using the formula given below.
Ilimit = (VREF/5) /RF resistance
The voltage applied to the VREF pin can be switched to any of the four setting levels depending on the statuses of the
two inputs, ATT1 and ATT2.
Function for attenuating VREF input voltage
ATT1
ATT2
Current setting reference voltage attenuation ratio
Low
Low
100%
High
Low
80%
Low
High
50%
High
High
20%
The formula used to calculate the output current when using the function for attenuating the VREF input voltage is
given below.
Ilimit = (VREF/5) × (attenuation ratio) /RF resistance
Example : At VREF of 1.5V, a reference voltage setting of 100% [(ATT1, ATT2) = (L, L)] and an RF resistance of
0.5Ω, the output current is set as shown below.
Ilimit = 1.5V/5 × 100%/0.5Ω = 0.6A
If, in this state, (ATT1, ATT2) has been set to (H, H), Ilimit will be as follows :
Ilimit = 0.6A × 20% = 120mA
No.A1824-18/26
LV8734V
3-4) Current LIMIT mask function
(Only the DCM mode. : It change the OE terminal at STM mode. It operates as output enable function. Refer to (output enable
function))
The mask can do current LIMIT function during the fixed time set with the CMK pin at the DCM mode. It is effective
to make it not hang to the limiter by the start current of the motor to set current LIMIT low.
The charge is begun, current LIMIT function is done to the CMK capacitor meanwhile when switching to forward/
reverse mode, and the mask is done. Afterwards, the mask is released when the voltage of the CMK pin reaches set
voltage (typ 1.5V), and the current limit function works.
When 2ch side begins forward (reverse) operation while the mask on 1ch side is operating, the CMK pin is discharged
one degree up to a constant voltage, and begins charging again because the CMK pin becomes 2ch using combinedly.
Meanwhile, 1ch side and 2ch side enter the state of the mask.
1ch operate
brake
forward
forward
brake
forward
2ch operate
brake
brake
brake
forward
brake
1.5V
CMK
(capacitor)
1ch
current limit
2ch
current limit
0.3V
mask
release
release
mask
release
release
mask
mask
mask
mask
When the capacitor is not connected, the function of LIMIT in the current can be switched to operation/no operating
state by the state of the input of the CMK pin.
CMK
Current LIMIT function
“L”
no operating
“H” or OPEN
operation
3-5) Current LIMIT mask time (Tcmk)
The time of the mask of current LIMIT function can be set by connecting capacitor CCMK between CMK pin - GND.
Decide the value of capacitor CCMK according to the following expressions.
Mask time : TCMK TCMK ≈ -CCMK × R × 1n ( 1- VtCMK / (ICMK × R )) (sec)
VtCMK : LIMIT mask threshold voltage typ. 1.5V
ICMK : CMK pin charge current typ. 25μA
R : Internal resistance typ. 100kΩ
No.A1824-19/26
LV8734V
3-6) Examples of current waveform in each micro-step mode when stepper motor parallel input control
Full step (CW mode)
DC11
DC12
DC21
DC22
(%)
100
I1
0
-100
(%)
100
I2
0
-100
Half step full torque (CW mode)
DC11
DC12
DC21
DC22
(%)
100
l1
0
-100
(%)
100
l2
0
-100
No.A1824-20/26
LV8734V
4.Output short-circuit protection function
This IC incorporates an output short-circuit protection circuit that, when the output has been shorted by an event such
as shorting to power or shorting to ground, sets the output to the standby mode and turns on the warning output in
order to prevent the IC from being damaged. In the stepping motor driver (STM) mode (DM = Low), this function
sets the output to the standby mode for both channels by detecting the short-circuiting in one of the channels. In the
DC motor driver mode (DM = High), channels 1 and 2 operate independently. (Even if the output of channel 1 has
been short-circuited, channel 2 will operate normally.)
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 type
In the latch mode, when the output current exceeds the detection current level, the output is turned OFF, and this state
is held.
The detection of the output short-circuited state by the IC causes the output short-circuit protection circuit to be
activated.
When the short-circuited state continues for the time of time set using the internal timer (approximately 2μs), the
output in which the short-circuiting has been detected is first set to OFF. After this, the output is set to ON again as
soon as the timer latch time (Tcem) described later has been exceeded, and if the short-circuited state is still detected,
all the outputs of the channel concerned are switched to the standby mode, and this state is held.
This state is released by setting ST to low.
Output ON
H-bridge
output state
Output ON
Output OFF
Standby state
Threshold voltage
CEM voltage
Short-circuit
detection state
Short- Release
circuit
Short-circuit
Internal counter
1st counter
start
1st counter 1st counter
stop
start
1st counter
end
2nd counter
start
2nd counter
end
No.A1824-21/26
LV8734V
4-3) Auto reset type
In the automatic reset mode, when the output current exceeds the detection current level, the output waveform
changes to the switching waveform.
As with the latch system, when the output short-circuited state is detected, the short-circuit protection circuit is
activated. When the operation of the short-circuit detection circuit exceeds the timer latch time (Tcem) described later,
the output is changed over to the standby mode and is reset to the ON mode again in 2ms (typ). In this event, if the
overcurrent mode still continues, the switching mode described above is repeated until the overcurrent mode is
canceled.
4-4) Unusual condition warning output pins (EMO, MONI)
The LV8731V is provided with the EMO pin which notifies the CPU of an unusual condition if the protection circuit
operates by detecting an unusual condition of the IC. This pin is of the open-drain output type and when an unusual
condition is detected, the EMO output is placed in the ON (EMO = Low) state.
In the DC motor driver mode (DM = High), the MONI pin also functions as a warning output pin.
The functions of the EMO pin and MONI pin change as shown below depending on the state of the DM pin.
When the DM is low (STM mode) :
EMO : Unusual condition warning output pin
MONI : Excitation initial position detection monitoring
When the DM is high (DCM) mode) :
EMO : Channel 1 warning output pin
MONI : Channel 2 warning output pin
Furthermore, the EMO (MONI) pin is placed in the ON state when one of the following conditions occurs.
1. Shorting-to-power, shorting-to-ground, or shorting-to-load occurs at the output pin and the output short-circuit
protection circuit is activated.
2. The IC junction temperature rises and the thermal protection circuit is activated.
Unusual condition
DM = L (STM mode)
DM = H (DCM mode)
EMO
MONI
EMO
MONI
Channel 1 short-circuit detected
ON
-
ON
-
Channel 2 short-circuit detected
ON
-
-
ON
Overheating condition detected
ON
-
ON
ON
4-5) Timer latch time (Tcem)
The time taken for the output to be set to OFF when the output has been short-circuited can be set using capacitor
Ccem, connected between the CEM pin and GND. The value of capacitor Ccem is determined by the formula given
below.
Timer latch : Tcem
Tcem ≈ Ccem × Vtcem/Icem [sec]
Vtcem : Comparator threshold voltage, typ 1V
Icem : CEM pin 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
TSD = 180°C (typ)
ΔTSD = 40°C (typ)
No.A1824-22/26
LV8734V
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.A1824-23/26
LV8734V
7.Application Circuit Example
7-1) Stepper motor driver circuit (DM = Low)
Short-circuit state
detection monitor
100pF
Position detection
monitor
Clock input
Logic input
OUT1A 44
2 VM
OUT1A 43
3 CP2
PGND 42
4 CP1
NC 41
5 VREG5
NC 40
6 ATT2
VM1 39
7 ATT1
VM1 38
8 EMO
RF1 37
9 CEM
RF1 36
10 EMM
OUT1B 35
11 CHOP
12 MONI
13 RST/BLK
24V
+ -
OUT1B 34
OUT2A 33
M
OUT2A 32
14 STEP/DC22
RF2 31
15 FR/DC21
RF2 30
16 MD2/DC12
VM2 29
17 MD1/DC11
VM2 28
18 DM
NC 27
19 OE/CMK
NC 26
20 ST
- +
LV8734V
180pF
1 VG
PGND 25
21 VREF
OUT2B 24
22 GND
OUT2B 23
1.0V
The formulae for setting the constants in the examples of the application circuits above are as follows :
Constant current (100%) setting
When VREF = 1.0V
IOUT = VREF/5/RF resistance
= 1.0V/5/0.22Ω = 0.91A
Chopping frequency setting
Fchop = Ichop/ (Cchop × Vtchop × 2)
= 10μA/ (180pF × 0.5V × 2) = 55kHz
Timer latch time when the output is short-circuited
Tcem = Ccem × Vtcem/Icem
= 100pF × 1V/10μA = 10μs
No.A1824-24/26
LV8734V
7-2) DC motor driver circuit (DM = High, and the current limit function is in use.)
Channel 1 short-circuit
state detection monitor
100pF
Channel 2 position
detection monitor
OUT1A 44
2 VM
OUT1A 43
3 CP2
PGND 42
4 CP1
NC 41
5 VREG5
NC 40
6 ATT2
VM1 39
7 ATT1
VM1 38
8 EMO
RF1 37
9 CEM
RF1 36
10 EMM
OUT1B 35
11 CHOP
12 MONI
LV8734V
180pF
1 VG
13 RST/BLK
24V
+ -
M
OUT1B 34
OUT2A 33
OUT2A 32
14 STEP/DC22
RF2 31
15 FR/DC21
RF2 30
16 MD2/DC12
VM2 29
17 MD1/DC11
VM2 28
M
Logic input
18 DM
NC 27
19 OE/CMK
NC 26
20 ST
- +
PGND 25
21 VREF
OUT2B 24
22 GND
OUT2B 23
1.0V
The formulae for setting the constants in the examples of the application circuits above are as follows :
Constant current limit (100%) setting
When VREF = 1.0V
Ilimit = VREF/5/RF resistance
= 1.0V/5/0.22Ω = 0.91A
Chopping frequency setting
Fchop = Ichop/ (Cchop × Vtchop × 2)
= 10μA/ (180pF × 0.5V × 2) = 55kHz
Timer latch time when the output is short-circuited
Tcem = Ccem × Vtcem/Icem
= 100pF × 1V/10μA = 10μs
No.A1824-25/26
LV8734V
ORDERING INFORMATION
Device
LV8734V-MPB-H
Package
SSOP44K (275mil)
(Pb-Free / Halogen Free)
LV8734V-TLM-H
SSOP44K (275mil)
(Pb-Free / Halogen Free)
Shipping (Qty / Packing)
30 / Fan-Fold
2000 / Tape & Reel
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PS No.A1824-26/26
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