LV8702V
PWM Constant-Current Control
High-Efficient Stepper Motor Driver
http://onsemi.com
Application Note
Overview
The LV8702V is a 2-channel Full-bridge driver IC that can drive a stepper motor driver, which is capable of
micro-step drive and supports quarter step. Current is controlled according to motor load and rotational
speed at half step, half step full-torque and quarter step excitation, thereby highly efficient drive is realized.
Consequently, the reduction of power consumption, heat generation, vibration and noise is achieved.
Function
• Built-in 1ch PWM current control stepper motor driver (bipolar type)
• Ron (High-side Ron: 0.3Ω, Low-side Ron: 0.25Ω, total: 0.55Ω, Ta = 25ºC, IO = 2.5A)
• Micro step mode is configurable as follows: full step/half step full-torque/half step/quarter step
• Excitation step moves forward only with step signal input
• Built-in output short protection circuit (latch method)
• Control power supply is unnecessary
• Built-in high-efficient drive function (supports half step full-torque/half step/quarter step excitation mode)
• Built-in step-out detection function (Step-out detection may not be accurate during high speed rotation)
• BiCDMOS process IC
• IO max=2.5A
• Built-in thermal shut down circuit
Typical Applications
• MFP (Multi Function Printer)
• PPC (Plain Paper Copier)
• Scanner
• Industrial
• Amusement
• Textile
Semiconductor Components Industries, LLC, 2013
December, 2013
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LV8702V Application Note
Package Dimensions
unit : mm (typ)
3285B
TOP VIEW
SIDE VIEW
BOTTOM VIEW
15.0
44
(3.6)
0.5
5.6
7.6
(7.8)
1
2
0.65
0.2
0.22
1.7 MAX
(0.68)
0.05 (1.5)
SIDE VIEW
SSOP44J(275mil)
Caution: The package dimension is a reference value, which is not a guaranteed value
Recommended Soldering Footprint
(Unit: mm)
Reference symbol
SSOP44J(275mil)
eE
7.00
e
0.65
b3
0.32
l1
1.00
X
(7.8)
Y
(3.5)
.
2 / 45
LV8702V Application Note
Pin Assignment
SWOUT
1
44 VM
CP2
2
43 VG
CP1
3
42 PGND1
GMG2
4
41 OUT1A
GMG1
5
40 OUT1A
GAD
6
39 VM1
FR
7
38 VM1
STEP
8
37 RF1
ST
9
36 RF1
RST 10
35 OUT1B
ADIN 11
34 OUT1B
MD2 12
LV8702V
MD1 13
33 OUT2A
32 OUT2A
VREG5 14
31 RF2
DST2 15
30 RF2
DST1 16
29 VM2
MONI 17
28 VM2
OE 18
27 OUT2B
SST 19
26 OUT2B
CHOP 20
25 PGND2
VREF 21
24 GST1
SGND 22
23 GST2
Top view
It is short-circuited in IC though there are VM1, VM2, OUT1A, OUT1B, OUT2A, OUT2B, RF1 and RF2 of each
of two pins.
3 / 45
LV8702V Application Note
Block Diagram
RF2
OUT2B
OUT2A
VM2
VM1
OUT1B
OUT1A
RF1
VG
CP1
CP2
VM
Charge pump
Pre-output
Pre-output
regulator
Pre-output
Pre-output
PGND
VREG5
MONI
Output control logic
+
+
VREF
+
-
Current
(W1-2/1-2/
1-2Full/2)
attenuat
Current
(W1-2/1-2/
1-2Full/2)
CHOP
Oscillator
SST
TSD
DST1
LVS
Signal
processor2
Signal
processor1
High-efficient drive ctrl logic
DST2
SGND
GAD
OE
RST
STEP
FR
MD2
MD1
GST2
GST1
GMG2
GMG1
SWOUT
ADIN
ST
4 / 45
LV8702V Application Note
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%
Output current
IO max
Per 1ch
Logic input voltage
VIN max
GMG1, GMG2 , GAD , FR , STEP , ST ,
Ratings
Unit
36
V
3
A
2.5
A
-0.3 to +6
V
-0.3 to +6
V
5.5
W
RST , MD1 , MD2 , OE , GST1 , GST2
DST1, DST2, MONI, SST input
Vdst1, Vdst2,
voltage
Vmoni, Vsst
Allowable power dissipation
Pd max
Operating temperature
Topr
-40 to +85
°C
Storage temperature
Tstg
-55 to +150
°C
Ta≤25°C *
* Specified circuit board: 90.0mm×90.0mm×1.6mm, glass epoxy 4-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.
Recommended Operating Conditions at Ta = 25°C
Parameter
Symbol
Conditions
Ratings
min
typ
Unit
max
Supply voltage range
VM
VM , VM1 , VM2
9
32
V
Logic input voltage
VIN
GMG1 , GMG2 , GAD , FR , STEP , ST ,
0
5.5
V
Range of VREF input voltage
VREF
0
3
V
RST , MD1 , MD2 , OE , GST1 , GST2
5 / 45
LV8702V Application Note
Electrical Characteristics at Ta = 25°C, VM = 24V, VREF = 1.5V
Parameter
Consumption current during
Symbol
Conditions
Ratings
min
typ
Unit
max
IMstn
ST = ”L” , I(VM)+I(VM1)+I(VM2)
110
400
μA
IM
ST = ”H”, OE = ”L”, STEP = ”L”, non-load
4.5
6.5
mA
standby
Consumption current
I(VM)+I(VM1)+I(VM2)
VREG5 output voltage
VREG5
IO = -1mA
4.5
5
5.5
V
Thermal shutdown temperature
TSD
Design certification
150
180
210
°C
Thermal hysteresis width
ΔTSD
Design certification
°C
40
Motor driver
Output on resistor
0.3
0.4
Ω
0.25
0.33
Ω
50
μA
1.2
1.4
V
4
8
12
μA
30
50
70
μA
Ronu
IO = 2.5A, Source-side Ron
Rond
IO = 2.5A, Sink-side Ron
Output leak current
IOleak
VM = 32V
Forward diode voltage
VD
ID = -2.5A
Logic pin input current
IINL
VIN = 0.8V
GMG1 , GMG2 , GAD, FR ,
IINH
VIN = 5V
STEP , ST , RST , MD1 ,
ADIN pin input voltage
Vadin
Ra2 = 100kΩ, refer to page 24
Logic input
High
VINH
GMG1 , GMG2 , GAD , FR , STEP , ST ,
voltage
Low
VINL
RST , MD1 , MD2 , OE , GST1 , GST2
Current
quarter step
Vtdac0_W
Step0 (initial status, 1ch comparator level)
290
Vtdac1_W
Step1 (initial + 1)
Vtdac2_W
Step2 (initial + 2)
Vtdac3_W
Vtdac0_H
selection
reference
voltage level
half step
half step
(full-torque)
full step
Chopping frequency
MD2 , OE , GST1 , GST2
0
12
V
2.0
5.5
V
0
0.8
V
300
310
mV
264
276
288
mV
199
210
221
mV
Step3 (initial + 3)
106
114
122
mV
Step0 (initial status, 1ch comparator level)
290
300
310
mV
Vtdac2_H
Step2 (initial + 1)
199
210
221
mV
Vtdac0_HF
Step0 (initial status, 1ch comparator level)
290
300
310
mV
Vtdac2’_HF
Step2’ (initial + 1)
290
300
310
mV
Vtdac2’_F
Step2’ (initial status, 1ch comparator level)
290
300
310
mV
Fchop
Cchop = 200pF
35
50
65
kHz
μA
CHOP pin charge/discharge current
Ichop
7
10
13
Chopping oscillation circuit
Vtup
0.8
1
1.2
V
threshold voltage
Vtdown
0.4
0.5
0.6
V
400
mV
V
VREF pin input current
Iref
VREF = 1.5V
DST1, DST2, MONI,SST pin
Vsatmoni
Idst1 = Idst2 = Imoni = Isst = 1mA
saturation voltage
Vsatsst
μA
-0.5
Charge pump
VG output voltage
VG
Rise time
tONG
Oscillator frequency
Fosc
28
28.7
29.8
500
μS
90
125
160
kHz
VG = 0.1μF
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LV8702V Application Note
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LV8702V Application Note
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LV8702V Application Note
Pin Functions
Pin No.
Pin Name
Pin Function
4
GMG2
Driving capability margin adjuster pin 2.
5
GMG1
Driving capability margin adjuster pin 1.
6
GAD
High-efficient drive switching pin.
7
FR
CW / CCW signal input pin.
8
STEP
STEP signal input pin.
10
RST
RESET signal input pin.
12
MD2
Excitation mode switching pin 2.
13
MD1
Excitation mode switching pin 1.
18
OE
Output enable signal input pin.
23
GST2
Boost-up adjuster pin 2.
24
GST1
Boost-up adjuster pin 1.
Equivalent Circuit
VREG5
10kΩ
100kΩ
GND
9
ST
Chip enable pin.
25
PGND2
Channel 2 power system ground.
26, 27
OUT2B
Channel 2 OUTB output pin.
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
40, 41
OUT1A
Channel 1 OUTA output pin.
42
PGND1
Channel 1 power system ground.
connection pin.
Channel 2 current-sense resistor
connection pin.
connection pin.
Channel 1 motor power supply
Connection pin.
Continued on next page.
9 / 45
LV8702V Application Note
Continued from preceding page.
Pin No.
Pin Name
Pin Function
2
CP2
Charge pump capacitor connection pin.
3
CP1
Charge pump capacitor connection pin.
43
VG
Charge pump capacitor connection pin.
44
VM
Motor power supply connection pin.
21
VREF
Equivalent Circuit
Constant current control reference
voltage input pin.
14
VREG5
Internal power supply capacitor
connection pin.
80kΩ
26kΩ
Continued on next page.
10 / 45
LV8702V Application Note
Continued from preceding page.
Pin No.
Pin Name
Pin Function
15
DST2
Drive status warning output pin 2.
16
DST1
Drive status warning output pin 1.
17
MONI
Position detection monitor pin.
19
SST
Motor stop detection output pin.
20
CHOP
Equivalent Circuit
Chopping frequency setting capacitor
connection pin.
1
SWOUT
Control signal output pin.
Continued on next page.
11 / 45
LV8702V Application Note
Continued from preceding page.
Pin No.
11
Pin Name
ADIN
Pin Function
Equivalent Circuit
Control signal input pin.
VM
2pF
2kΩ
100kΩ
2pF
GND
22
SGND
Signal ground.
12 / 45
LV8702V Application Note
Description of operation
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) Chip enable function
The mode of the IC is switched with ST pin between standby and operation mode. In standby mode, the IC
is set to power saving mode and all the logics are reset. During standby mode, the operation of the internal
regulator circuit and the charge pump circuit are stopped.
ST
Mode
Internal regulator
Charge pump
Low or Open
Standby mode
Standby
Standby
High
Operating mode
Operating
Operating
(2) STEP pin function
The excitation step progresses by inputting the step signal to the STP pin.
Input
Operating mode
ST
STEP
Low or Open
X*
Standby mode
High
Excitation step proceeds
High
Excitation step is kept
*: Don’t care
STEP input MIN pulse width (common in H/L): 12.5us (MAX input frequency: 40kHz)
However, constant current control is performed by PWM during chopping period, which is set by the
capacitor connected between CHOP and GND. You need to perform chopping more than once per step.
For this reason, for the actual STEP frequency, you need to take chopping frequency and chopping count
into consideration.
For example, if chopping frequency is 50kHz (20μs) and chopping is performed twice per step, the
maximum STEP frequency is obtained as follows: f＝1/(20μs×2) = 25kHz.
13 / 45
LV8702V Application Note
(3) Input timing
RST
Tds1
(RST→STEP)
Tsteph Tstepl
STEP
Tds1
(MD→STEP)
MD1/
MD2
Tdh1
(STEP→MD)
Tds1
(FR→STEP)
Tdh1
(STEP→FR)
FR
Tds1
(OE→STEP)
Tdh1
(STEP→OE)
OE
Tds2
Tdh2
(GAD→STEP) (STEP→GAD)
GAD
Tds2
Tdh2
(GMG→STEP) (STEP→GMG)
GMG1/
GMG2
Tds2
Tdh2
(GST→STEP) (STEP→GST)
GST1/
GST2
TstepH/TstepL : Clock H/L pulse width (min 12.5us)
Tds1 : Data set-up time (min 12.5us)
Tdh1 : Data hold time (min 12.5us)
Tds2 : Data set-up time (min 25us)
Tdh2 : Data hold time (min 25us)
Figure 15. Input timing chart
(4) 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 "Examples of current waveforms in each micro-step mode.")
(5) 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.
For example, where VREF=1.5V and RF resistance 0.2Ω, we obtain output current as follows.
IOUT = 1.5V/5/0.2Ω = 1.5A
When high-efficient drive function is on, IOUT is adjusted automatically within the range of the current
value set by VREF.
If VREF is open or the setting is out of the recommendation operating range, output current will increase
and you cannot set constant current under normal condition. Hence, make sure that VREF is set in
accordance with the specification.
However, if current control is not performed (if the IC is used by saturation drive) make sure that the setting
is as follows: VREF=5V or VREF=VREG5
Power dissipation of RF resistor is obtained as follows: Pd=Iout2×RF. Make sure to take allowable power
dissipation into consideration when you select RF resistor.
14 / 45
LV8702V Application Note
(6) Reset function
RST
Operating mode
Low or Open
Normal operation
High
Reset state
RST
RESET
STEP
MONI
1ch
output
0%
2ch
output
Initial state
Figure 16. Reset operation
When RST pin = “H”, the excitation position of the output is set to the initial position forcibly and MONI
output is turned on. And then by setting RST = “L”, the excitation position moves forward with the next step
signal.
(7) Output enable function
OE
Operating mode
Low or Open
Output ON
High
Output OFF
OE
Power save mode
STEP
MONI
1ch
output
0%
2ch
output
Output is high-impedance
Figure 17. Output enable operation
When OE pin = “H”, the output is turned off forcibly and becomes a high-impedance output.
However, since the internal logic circuit is in operation, an excitation position moves forward if step signal is
input to STEP pin. Therefore, by setting back to OE = “L”, the output pin outputs signal based on the
excitation position by step signal.
15 / 45
LV8702V Application Note
(8) Excitation mode setting function
MD1
MD2
Low or Open
Micro-step resolution (Excitation mode)
Low or Open
Initial position
Full step
Channel 1
Channel 2
100%
-100%
100%
0%
100%
0%
100%
0%
(2 phase excitation)
High
Low or Open
Half step
(1-2 phase excitation)
Low or Open
High
1/4 step
(W1-2 phase excitation)
High
High
Half step full-torque
(1-2 phase full-torque excitation)
The position of excitation mode is set to the initial position when: 1) a power is supplied and 2) counter is
reset in each excitation mode.
During full step excitation mode, high-efficient drive function is turned off even when GAD = “H”.
(9) Forward/Reverse switching function
FR
Operating mode
Low or Open
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
Figure 18. FR operation
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.
16 / 45
LV8702V Application Note
(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
The higher the chopping frequency is, the greater the output switching loss becomes. As a result, heat
generation issue arises. The lower the chopping frequency is, the lesser the heat generation becomes.
However, current ripple occurs. Since noise increases when switching of chopping takes place, you need
to adjust frequency with the influence to the other devices into consideration. The frequency range should
be between 40kHz and 125kHz.
(11)Blanking period
If you attempt to control PWM constant current chopping of the motor current, when the mode shifts from
DECAY to CHARGE, noise is generated in sense resistor pin due to the recovery current of parasitic diode
flowing into current sense resistor, and this may cause error detection. The blanking time avoids noise at
mode switch. During the blanking time, even if noise is generated in sense resistor, a mode does not
switch from CHARGE to DECAY.
In this IC, the blanking time is fixed to approximately 1μs.
17 / 45
LV8702V Application Note
(12)Output current vector locus (one step of full step is normalized at 90 degrees)
100
,
θ2 (full step, half step full-torque)
θ0
θ1
80
1ch phase current ratio (%)
θ2
60
40
θ3
20
0
θ4
0
40
20
80
60
100
2ch phase current ratio (%)
Figure 19. Current vector position
Setting current ration in each excitation mode
STEP
quarter step (%)
1ch
half step (%)
2ch
1ch
θ0
100
0
θ1
92
38
θ2
70
70
θ3
38
92
θ4
0
100
half step full-torque (%)
2ch
1ch
full step (%)
2ch
1ch
100
0
100
0
70
70
100
100
0
100
0
100
2ch
100
100
18 / 45
LV8702V Application Note
(13)Micro-step mode switching operation
When micro-step mode is switched while the motor is rotating, each drive mode operates with the following
sequence.
Clockwise mode
Before the micro-step mode changes
Micro-step mode
Position
1/4 step
Half step
Half step full-torque
Full step
1/4 step
Position after the micro-step mode is changed
Half step
Half step full-torque
Full step
θ0
θ2
θ2’
θ2’
θ1
θ2
θ2’
θ2’
θ2
θ4
θ4
θ2’
θ3
θ4
θ4
θ2’
θ4
-θ2
θ6’
-θ2’
θ2’
θ0
θ1
θ2’
θ2
θ3
θ4
θ2’
θ4
-θ3
-θ2’
-θ2’
θ2’
θ0
θ1
θ2
θ2’
θ3
θ4
θ2’
θ4
-θ3
-θ2
-θ2’
θ2’
θ3
θ4
θ4
*As for θ0 to θ4, please refer to the step position of setting current ratio.
If you switch excitation mode while the motor is driving, the mode setting will be reflected from the next
STEP and the motor advances to the closest excitation position at switching operation.
19 / 45
LV8702V Application Note
(14)The example of current waveform in each excitation mode
Full step (CW mode)
STEP
MONI
（％） 100
I1
0
－100
（％） 100
I2
0
－100
Figure 20. Current waveform of Full step in CLK-IN
Half step full-torque (CW mode)
STEP
MONI
(%) 100
I1
0
－100
(%) 100
I2
0
－100
Figure 21. Current waveform of Half step full-torque in CLK-IN
20 / 45
LV8702V Application Note
Half step (CW mode)
STEP
MONI
(%) 100
I1
0
－100
(%) 100
I2
0
－100
Figure 22. Current waveform of Half step in CLK-IN
Quarter step (CW mode)
STEP
MONI
(%) 100
I1
0
－100
(%) 100
I2
0
－100
Figure 23. Current waveform of Quarter step in CLK-IN
21 / 45
LV8702V Application Note
(15)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
Set current
FAST
Forced CHARGE
section
FAST
CHARGE
SLOW
Figure 24. Current control operation
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.
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LV8702V Application Note
(16)High-efficient drive function
This IC includes high-efficient drive function. When high-efficient drive function is turned on, IOUT is
adjusted automatically within the current value set with VREF pin. When high-efficient drive function is
turned off, the current value of IOUT becomes the maximum value set by VREF pin.
It is recommended to evaluate the actual set with the load, because a high efficient is not stable when there
is not a load.
1) High-efficient drive enable function
High-efficient drive function is switched on and off with GAD pin.
However, in the case of full step excitation mode (MD1 = MD2 = “L”), even when GAD = “H”,
high-efficient drive function is turned off.
Even if you adjust the GMG1, GMG2 of 15-2) and GST1, GST2 of 15-3), in the case of abrupt motor
acceleration or load variation to the extent that auto adjuster cannot follow up and eventually leads to the
rotation stepping-out, it is recommended that you turn off the high-efficient drive function temporally. As
high-efficient control may become unstable due to the control signal from the motor is unstable during
low speed rotation, it is also recommended to turn off this function as well.
GAD
Operation mode
Low or OPEN
Normal mode
High
High-efficient mode
(except for full step excitation mode)
Recommended speed of high-efficient drive
excitation
Operating conditions
Speed
over 1500pps
half step
HB motor/no-load
half step full-torque
PM motor/no-load
over 1000pps
quarter step
HB motor/no-load
over 3000pps
PM motor/no-load
over 2500pps
When there is a load, the high-efficient drive is enabled at slower speed.
2) High-efficient drive margin adjuster function
By setting GMG1 and GMG2 pin, margin for step-out is adjusted.
Where GMG1 = GMG2 = “L”, IOUT and consumption current are at the lowest. In some case, as the
IOUT becomes lower, the number of boost-up process* may increase triggered by slight change of load.
With insufficient driving capability, you need to increase the margin setting. One way to set GMG1 and
GMG2 is to minimize boost-up level, then lower the margin from high to low to optimize the margin where
motor rotates stably.
In the application where load variation is excessive, you need to have a larger margin.
GMG1
GMG2
Setting
Current consumption
Load following capability
Low or OPEN
High
Low or OPEN
Margin: small
Smallest
Ordinary
Low or OPEN
Margin: middle
Smaller
Good
Low or OPEN
High
Margin: large
Small
Better
High
High
Setting is inhibited
-
-
*: This is a function to increase IOUT rapidly as soon as a possible stepping out is detected due to load
variation during high efficiency drive.
23 / 45
LV8702V Application Note
3) Boost-up adjuster function
During high-efficient drive, boost-up adjuster function detects a possibility of step-out caused by such
factors as abrupt load variation and then boosts up IOUT at once (Boost-up process). You can set a level
of boost-up by setting GST1 and GST2 pins. One way to set GST1 and GST2 is to increase boost-up
level from minimum to maximum within the maximum load condition and select the optimum boost-up
setting where motor rotates without stepping out. Also, boost-up level varies depends on reference
current defined by VREF. Therefore, you can increase load following capability by increasing VREF
voltage.
The higher the boost-up level is, the more the IC becomes tolerant for abrupt load variation. However,
rotation stability may become poor (vibration and rotation fluctuation may occur) because excessively
high boost-up level leads to rapid increase of IOUT at load variation. You may be able to improve poor
rotation stability with high boost-up level by increasing high-efficient drive margin.
GST1
GST2
Setting
Increase of Iout
load following capability
Rotation stability
Low or OPEN
Low or OPEN
Boost-up level minimum
{(VREF/5)/RF resistance}
Ordinary
Best
Good
Better
Better
Good
Best
Ordinary
× 1/128
High
Low or OPEN
Boost-up level low
{(VREF/5)/RF resistance}
× 4/128
Low or OPEN
High
Boost-up level high
{(VREF/5)/RF resistance}
× 16/128
High
High
Boost-up level maximum
{(VREF/5)/RF resistance}
× 64/128
4) External component
The resistance value of Ra1, Ra2 (control signal resistors) is adjusted in such a way as to set the
maximum SWOUT output voltage during motor rotation to 12V in ADIN pin. Preferably, resistance
values of Ra1 and Ra2 are as high as possible to the extent that does not influence waveform.
(Recommendation for Ra1: 15kΩ, Ra2: 100kΩ).
In some motor where boost-up process occurs at a high speed rotation of 7000pps to 8000pps or higher
(HB motor: Half step excitation), you can suppress boost-up by lowering Ra1. Moreover, you can
achieve high efficiency at lower speed of 1500pps or lower by increasing resistance for Ra1 (HB motor:
Half step excitation).
Although it depends on a usage motor, step-out is detectable at higher speed rotation by attaching
smaller resistor for Ra1.
SWOUT
Ra2
ADIN
Ca
Ra1
Figure25. ADIN filter circuit
24 / 45
LV8702V Application Note
(17)Output transistor operation mode
Charge increases
current.
Switch from Charge to
Slow Decay
4.
5. FAST
6.
VM
VM
VM
OFF
OFF
U1
OFF
U2
OUTA
Current regeneration by
Slow Decay
OUTA
L1
L2
RF
OUTB
OF
F
OFF
L2
L1
RF
Switch from Slow Decay to
Fast Decay
U2
OUTA
OF
F
L1
OFF
U1
OUTB
ON
OFF
OFF
U2
OUTB
ON
ON
U1
L2
RF
Switch from Fast Decay to
Charge
Current regeneration by
Fast Decay
Figure 26. Switching operation
This IC controls constant current by performing chopping to output transistor.
As shown above, by repeating the process from 1 to 6, setting current is maintained.
Chopping consists of 3 modes: Charge/ Slow decay/ Fast decay. In this IC, for switching mode (No.2, 4, 6),
there are “off period” in upper and lower transistor to prevent crossover current between the transistors. This
off period is set to be constant (≈ 0.375μs) which is controlled by the internal logic. The diagrams show
parasitic diode generated due to structure of MOS transistor. When the transistor is off, output current is
regenerated through this parasitic diode.
Output Transistor Operation Function
OUTA→OUTB (CHARGE)
Output Tr
U1
U2
L1
L2
OUTB→OUTA (CHARGE)
Output Tr
U1
U2
L1
L2
CHARGE
ON
OFF
OFF
ON
SLOW
OFF
OFF
ON
ON
FAST
OFF
ON
ON
OFF
CHARGE
OFF
ON
ON
OFF
SLOW
OFF
OFF
ON
ON
FAST
ON
OFF
OFF
ON
25 / 45
LV8702V Application Note
VM=24V
VREF=0.55V
VDD=5V
STEP=700pps
STEP
5V/div
1
Half step
GMG1=H,
GMG2=L
GST1=H,
GST2=L
Motor Current
0.2A/div
3
RF=0.22Ω
CHOP=150pF
No-load
CHOP
0.5V/div
2
2ms/div
Sine wave increasing direction
Sine wave decreasing direction
STEP
5V/div
1
16us(typ)
Set Current
Internal STEP
3
STEP
5V/div
1
16us(typ)
Motor Current
0.2A/div
CHOP
0.5V/div
Set Current
Internal STEP
3
Motor Current
0.2A/div
CHOP
0.5V/div
2
2
20us/div
20us/div
Since STEP is synchronized with the IC,
the current rise of motor also synchronizes
with internal signal.
Since STEP is synchronized with the IC,
the current fall of motor also synchronizes
with internal signal.
Figure 27. Current control operation waveform
Current mode
Motor Current
0.2A/div
CHOP
0.5V/div
FAST
CHARGE
SLOW
5us/div
Figure 28. Chopping waveform
Motor current switches to Fast Decay mode when triangle wave (CHOP) switches from Discharge to Charge.
Approximately after 1μs, the motor current switches to Charge mode. When the current reaches to the
setting current, it is switched to Slow Decay mode which continues over the Discharge period of triangle
wave.
26 / 45
LV8702V Application Note
High-efficient mode
When this driver shows GAD=”H”, it is in high efficient mode where drive current is adjusted automatically
according to motor rotational speed and the change of load. By lowering the current, power consumption,
heat generation, vibration and noise are reducible.
(1) The reduction of motor current
VM=24V
VREF=0.55V
VDD=5V
STEP=700pps
Half step
GMG1=H,
GMG2=L
GST1=H,
GST2=L
STEP
5V/div
1
Motor Current
0.2A/div
3
RF=0.22Ω
CHOP=150pF
No-load
100ms/div
Normal drive mode (GAD=”L”)
High-efficient mode (GAD=”H”)
STEP
5V/div
1
3
Motor Current
0.2A/div
STEP
5V/div
1
3
5ms/div
Motor Current
0.2A/div
5ms/div
Figure 29. Normal drive mode -> High efficient mode Motor current waveform
Motor current is adjusted according to rotational speed and load by setting high efficiency mode (GAD=”H”).
The smaller the load is, the better the driving efficiency becomes.
27 / 45
LV8702V Application Note
(2) Motor current by different setting current.
VREF=0.55V (Iout=500mA)
STEP
5V/div
1
Half step
GMG1=H, GMG2=L
GST1=H, GST2=L
500mA
About 240mA
3
VM=24V
VDD=5V
STEP=700pps
Motor
Current
0.2A/div
RF=0.22Ω
CHOP=150pF
No-load
100ms/div
VREF=0.44V (Iout=400mA)
STEP
5V/div
1
400mA
3
About 240mA
Motor
Current
0.2A/div
100ms/div
Figure 30. Motor current waveform by setting current
Whichever setting current is selected (Iout=500mA/ 400mA), after current adjustment the motor current will
be the same according to rotational speed and load.
Taking the possibility of additional load into consideration, current should be set higher and reduce current
consumption at light load by high efficiency mode.
28 / 45
LV8702V Application Note
(3) Difference in motor current by margin setting for high efficiency drive (GMG1,GMG2)
Margin small (GMG1=L, GMG2=L)
Margin middle (GMG1=H, GMG2=L)
500mA
500mA
About 200mA
3
About 240mA
3
100ms/div
Motor
Current
0.2A/div
100ms/div
Margin large (GMG1=L, GMG2=H)
VM=24V
VREF=0.55V
VDD=5V
STEP=700pps
500mA
3
Half step
GST1=H, GST2=L
About 270mA
Motor
Current
0.2A/div
RF=0.22Ω
CHOP=150pF
Load=no-load
100ms/div
Figure 31. Motor current waveform by high efficiency margin setting
Motor driving capability at high efficiency mode is configurable by changing margin setting.
Margin setting enables to adjust the margin of rotor phase against a target phase. Therefore, driving current
after the adjustment varies depends on motor type and load. Make sure to check the motor current at high
efficiency mode using the actual application.
Driving capability is the lowest at “Margin small” (GMG1=L, GMG2=L) and the highest at “Margin large”
(GMG1=L, GMG2=H).
When the driving capability is lower against the usage load, in some case, the number of boost-up process*
may increase. In this case, increase the margin setting to adjust the driving capability.
In the application where load variation is excessive, you need to have a larger margin.
*: This is a function to increase IOUT rapidly as soon as a possible stepping out is detected due to load
variation during high efficiency drive.
29 / 45
LV8702V Application Note
(4) Difference in motor current by boost-up setting (GST1,GST2)
Boost-up minimum (GST1=L, GST2=L)
Boost-up low (GST1=H, GMG2=L)
500mA
500mA
3
Motor
Current
0.2A/div
3
100ms/div
100ms/div
Boost-up high (GMG1=H, GMG2=L)
Boost-up maximum (GMG1=H, GMG2=H)
500mA
500mA
Motor
Current
0.2A/div
3
3
100ms/div
100ms/div
VM=24V, VREF=0.55V, VDD=5V, STEP=700pps, Half step
GMG1=H, GMG2=L, RF=0.22Ω, CHOP=150pF
Figure 32. Motor current waveform by boost-up setting
When the rotor phase of motor delays due to the variation of load and the IC determined that more driving
current is needed, boost-up process is operated to increase Iout rapidly. See (16) – 3) Boost-up adjuster
function for the level of lout increase by boost-up process. The motor current waveform by boost-up setting is
as shown above.
The higher the boost-up level is, the more the IC becomes tolerant for abrupt load variation. However,
caution is required for loosing stability in rotation by increasing Iout rapidly.
30 / 45
LV8702V Application Note
(5) Step-out detection function
Step-out state is detectable only in high efficient mode. When step-out is detected, DTS1 pin is turned “L” for
1 STEP period. In some case step-out cannot be detected depends on motor type and rotational speed.
Hence, make sure to check the operation using the actual usage application.
Without Step-out
STEP
5V/div
1
Motor
Current
0.2A/div
3
VM=24V
VREF=0.55V
VDD=5V
STEP=700pps
Half step
GMG1=H, GMG2=L
GST1=L, GST2=L
RF=0.22Ω
CHOP=150pF
DST1
5V/div
2
5ms/div
With Step-out
STEP
5V/div
1
Motor
Current
0.2A/div
3
DST1
5V/div
Step-out
2
Turns L for
1step period.
5ms/div
Figure 33. Step-out detection waveform
31 / 45
LV8702V Application Note
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 stepper 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.)
(1) Output short-circuit detection operation
Short to Power
VM
VM
Tr1
Tr1
Tr3
ON
OUTA
1.High current flows if OUTB short to VM
and Tr4 are ON.
2.If RF voltage> setting voltage, then the
mode switches to SLOW decay.
3.If the voltage between Drain and
Source of Tr4 exceeds the reference
voltage for 2μs, short status is detected.
OFF
OUTA
OFF
OUTB
M
Tr2
OFF
Tr3
Tr4
Tr2
ON
ON
OFF
OUTB
M
Tr4
ON
RF
RF
Short-circuit
Detection
Short to GND
Short-circuit
Detection
VM
Tr1
ON
OUTA
Tr3
M
Tr2
OFF
RF
Load short
Short-circuit
Detection
OFF
OUTB
VM
Tr1
ON
OUTA
Tr4
Tr2
ON
OFF
Tr3
M
OFF
OUTB
Tr4
ON
RF
(left schematic)
1.High current flows if OUTA short to
GND and Tr1 are ON
2. If the voltage between Drain and
Source of Tr1 exceeds the reference
voltage for 2μs, short status is detected.
(right schematic)
1. Without going through RF resistor,
current control does not operate and
current will continue to increase in
CHARGE mode.
2. If the voltage between Drain and
Source of Tr1 exceeds the reference
voltage for 2μs, short status is detected.
1. Without L load, high current flows.
2. If RF voltage> setting voltage, then the
mode switches to SLOW decay.
3. During load short stay in SLOW decay
mode, current does not flow and over
current state is not detected. Then the
mode is switched to FAST decay
according to chopping cycle.
4. Since FAST state is short (≈1μs),
switches to CHARGE mode before short
is detected.
5. If voltage between Drain and Source
exceeds the reference voltage
continuously during blanking time at the
start of CHARGE mode (Tr1), CHARGE
state is fixed (even if RF voltage
exceeds the setting voltage, the mode is
not switched to SLOW decay). After 2us
or so, short is detected.
32 / 45
LV8702V Application Note
(2) Output short-circuit protection detect current (Reference value)
Short protector operates when abnormal current flows into the output transistor.
Ta = 25°C (typ)
Output Transistor
LV8702V
Upper-side Transistor
3.7A
Lower-side Transistor
3.8A
*RF=GND
33 / 45
LV8702V Application Note
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
Figure 35. VG pin voltage schematic view
VG voltage is used to drive upper output FET and VREG5 voltage is used to drive lower output FET.
Since VG voltage is equivalent to the addition of VM and VREG5 voltage, VG capacitor should allow higher
voltage.
The capacitor between CP1 and CP2 is used to boost charge pump. Since CP1 oscillates with 0V↔VREG5
and CP2 with VM↔VM＋VREG5, make sure to allow enough capacitance between CP1 and CP2.
Since the capacitance is variable depends on motor types and driving methods, please check with your
application before you define constant to avoid ripple on VG voltage.
(Recommended value)
VG: 0.1μF
CP1-CP2: 0.1μF
tONG: Rise time of Charge pump
1
50μs/div
Startup time with different VG capacitor
1
500μs/div
ST
5V/div
VM+4V
VG
5V/div
Vout
10V/div
4
4
0.1μF /250us
2
tONG
1μF /2.9ms
2
VM=24V
CP1-CP2=0.1μF
VG=0.1μF
VM=24V
CP1-CP2=0.1μF
VG=0.1μF/1μF
Figure 36. VG voltage pressure waveform
34 / 45
LV8702V Application Note
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)
∆TSD=40°C(typ)
35 / 45
LV8702V Application Note
Application Circuit Example
Make sure that ADIN is 12V or less
since constant varies depends on
user applications.
ADIN = (VM+VD) × Ra1/(Ra1+Ra2)
VD: voltage for diode
Ca: capacitor for filter
Ra1
Ra2
+ -
1 SWOUT
VM 44
2 CP2
VG 43
3 CP1
PGND1 42
4 GMG2
OUT1A 41
5 GMG1
OUT1A 40
0.1μF
10μF
0.1μF
Ca
logic
input
6 GAD
VM1 39
7 FR
VM1 38
CLOCK input
8 STEP
RF1 37
logic input
9 ST
RF1 36
11 ADIN
12 MD2
logic
input
0.1μF
13 MD1
47kΩ 47kΩ 47kΩ
short/stepout
detection
monitor
As for Rsst, refer to
18.current save function.
LV8702V
10 RST
0.22Ω
OUT1B 35
OUT1B 34
OUT2A 33
M
OUT2A 32
14 VREG5
RF2 31
15 DST2
RF2 30
16 DST1
VM2 29
17 MONI
VM2 28
18 OE
OUT2B 27
19 SST
OUT2B 26
20 CHOP
PGND2 25
21 VREF
GST2 24
22 SGND
GST2 23
0.22Ω
Rsst
150pF
VREF
30kΩ
68kΩ
logic
input
- +
5V
Figure 37. Application Circuit diagram
Calculation for each constant setting according to the above circuit diagram is as follows.
1) Constant current (100%) setting
2) Chopping frequency setting
VREF = 5V×30kΩ/(68kΩ + 30kΩ) ≈ 1.53V
Fchop = Ichop/(Cchop×Vtchop×2)
When VREF = 1.53V:
=10μA/(150pF×0.5V×2)
IOUT = VREF/5/0.22Ω ≈ 1.39A
≈ 66.7kHz
36 / 45
LV8702V Application Note
Allowable power dissipation
The pad on the backside of the IC functions as heatsink by soldering with the board. Since the heat-sink
characteristics vary depends on board type, wiring and soldering, please perform evaluation with your board
for confirmation.
Specified circuit board: 90mm x 90mm x 1.6mm, glass epoxy 4-layer board
Allowable power dissipation, Pd max -- W
6.0
Pd max -- Ta
Four-layer circuit board *1
5.5
5.0
4.0
Four-layer circuit board *2
3.8
3.0
2.9
2.0
2.0
1.0
*1 With components mounted on the exposed die-pad board
*2 With no components mounted on the exposed die-pad board
0
--40
--20
0
20
40
60
80
100
Ambient temperature, Ta -- °C
Figure 38. Pdmax – Ta Characteristic
37 / 45
LV8702V Application Note
Substrate Specifications (Substrate recommended for operation of LV8702V)
Size
: 90mm × 90mm × 1.6mm (Four-layer substrate)
Material
: Glass epoxy
Copper wiring density
: L1 = 85%, L2 = 90%
L1: Copper wiring pattern diagram
L2: Copper wiring pattern diagram
L3: GND layer
L4: Power supply layer
Figure 39. Substrate layout 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
stress 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
(However this does not apply to high efficiency drive because operating current is lower than the setting
current.)
(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
38 / 45
LV8702V Application Note
conduction, possibly resulting in thermal destruction of IC.
39 / 45
LV8702V Application Note
Evaluation board
LV8702V (90.0mm×90.0mm×1.6mm, glass epoxy 4-layer board, with backside mounting)
“VM” Power
Supply
“VREF”
Reference
Voltage
“VDD”
Power Supply
for Switch
Figure 40. Evaluation board
Bill of Materials for LV8702V Evaluation Board
Designator
Quantity
Description
Value
Tolerance
C1
1
VM Bypass Capacitor
10µF,
50V
±20%
C2
1
C3
1
C4
C5
1
1
C6
1
R1
1
R2
1
Capacitor
for Charge pump
Capacitor
for filter of control
signal
Capacitor
for Charge pump
VREG5 stabilization
Capacitor
Capacitor to set
chopping frequency
Channel 1 output
current detective
Resistor
Channel 2 output
current detective
Resistor
Footprint
0.1µF,
100V
±10%
1608
(0603Inch)
1000pF
, 50V
±5%
1608
(0603Inch)
±10%
1608
(0603Inch)
0.1µF,
100V
0.1µF,
100V
Manufacturer
Part Number
Substitution
Allowed
Lead
Free
SUN Electronic
Industries
50ME10HC
Yes
Yes
Murata
GRM188R72A
104KA35*
Yes
Yes
Murata
GRM1882C1H
102JA01*
Yes
Yes
Murata
GRM188R72A
104KA35*
Yes
Yes
Manufacturer
±10%
1608
(0603Inch)
Murata
GRM188R72A
104KA35*
Yes
Yes
150pF,
50V
±5%
1608
(0603Inch)
Murata
GRM1882C1H
151JA01*
Yes
Yes
0.22Ω,
1W
±5%
6432
(2512Inch)
ROHM
MCR100JZHJLR22
Yes
Yes
0.22Ω,
1W
±5%
6432
(2512Inch)
ROHM
MCR100JZHJLR22
Yes
Yes
±5%
1608
(0603Inch)
KOA
RK73B1JT**153J
Yes
Yes
KOA
RK73B1JT**104J
Yes
Yes
1
Resistor for filter of
control signal
15kΩ,
1/10W
1
Resistor for filter of
control signal
100kΩ,
1/10W
±5%
1608
(0603Inch)
1
Pull-up Resistor for
terminal DST2
47kΩ,
1/10W
±5%
1608
(0603Inch)
KOA
RK73B1JT**473J
Yes
Yes
1
Pull-up Resistor for
terminal DST1
47kΩ,
1/10W
±5%
1608
(0603Inch)
KOA
RK73B1JT**473J
Yes
Yes
R7
1
Pull-up Resistor for
terminal MONI
47kΩ,
1/10W
±5%
1608
(0603Inch)
KOA
RK73B1JT**473J
Yes
Yes
IC1
1
Motor Driver
SSOP44K
(275mil)
ON
semiconductor
LV8702V
No
Yes
SW1-SW11
11
Switch
MIYAMA
MS-621C-A01
Yes
Yes
TP1-TP29
33
Test Point
MAC8
ST-1-3
Yes
Yes
R3
R4
R5
R6
40 / 45
LV8702V Application Note
Evaluation board circuit
C7
C1
R3 ※2
1
SWOUT
VM
44
2
CP2
VG
43
3
CP1
PGND1
42
4
GMG2
OUT1A
41
5
GMG1
OUT1A
40
6
GAD
VM1
39
7
FR
VM1
38
8
STEP
RF1
37
9
ST
RF1
36
10
RST
OUT1B
35
11
ADIN
OUT1B
34
12
MD2
OUT2A
33
13
MD1
OUT2A
32
RF2
31
RF2
30
R4
C2
C4
C3
(1)
R6
R7
(2)
LV8702V
14 VREG5
R5
15 DST2
C5
(3)
モータ接続端子
Motor connection pins
R1
(4)
R2
16
DST1
VM2
29
17
MONI
VM2
28
18
OE
OUT2B
27
19
SST
OUT2B
26
20
CHOP
PGND2
25
21
VREF
GST1
24
22
SGND
GST2
23
VDD ※1
R8
C6
VREF
R10
R9
Figure 41. Evaluation board circuit diagram
*1 VDD is a power supply pin for SW/Nch open-drain. By supplying 3.3V or 5V, logic input setting is
enabled. VDD is also the pull-up power supply for Nch open-drain.
*2 By increasing R3 resistor, high efficient operation is stabilized at low speed rotation (at 1/2 step:
1000pps or lower)
Also by decreasing R3 resistor, high efficient operation is stabilized at high speed rotation (at 1/2 step:
10000pps or higher).
(Frequency for stable operation varies depends on motor and load.)
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LV8702V Application Note
Motor drive waveform
Full step (STEP=400pps, MD1=L, MD2=L)
1
2
(1)
Half step full-torque (STEP=800pps, MD1=H, MD2=H)
1
(2)
(4)
2
(1)
STEP
5V/div
(2)
MONI
5V/div
(3)
(3) (4)
3 4
Iout1A
0.5A/div
3 4
Iout2A
0.5A/div
20ms/div
Half step (STEP=800pps, MD1=H, MD2=L)
1
2
(1)
Quarter step (STEP=800pps, MD1=L, MD2=H)
1
(2)
2
(1)
STEP
5V/div
(2)
MONI
5V/div
(3)
(3) (4)
3 4
(4)
3 4
Iout1A
0.5A/div
Iout2A
0.5A/div
VM=24V, VDD=5V, VREF=0.55V
GAD=L
GMG1=H, GMG2=L
GST1=H, GST2=L
FR=L, RST=L, OE=L
ST=H
STEP, MD1 and MD2 are above conditions
Figure 42. Motor current waveform of each micro step
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LV8702V Application Note
Evaluation Board Manual
[Supply Voltage]
VM (9 to 32V)
VREF (0 to 3V)
VDD (2 to 5V)
: Power Supply for LSI
: Const. Current Control for Reference Voltage
: Logic “High” voltage for toggle switch
[Toggle Switch State]
Upper Side
Middle
Lower Side
: High (VDD)
: Open, enable to external logic input
: Low (GND)
[Operation Guide]
1. Motor Connection: Connect the Motors between OUT1A and OUT1B, between OUT2A and
OUT2B.
2. Initial Condition Setting: Set “Open” the toggle switch STEP, and “Open or Low” the other
switches.
3. Power Supply: Supply DC voltage to VM, VREF and VDD.
4. Ready for Operation from Standby State: Turn “High” the ST terminal toggle switch. Channel 1
and 2 are into Full step initial position (100%, -100%).
5. Motor Operation: Input the clock signal into the terminal STEP.
6. Other Setting
i. GAD: High efficient drive enable.
ii. GMG1/GMG2 : High efficient drive margin setting.
iii. GST1/GST2: Boost-up level setting.
iv. FR: Motor rotation direction (CW / CCW) setting.
v. RST: Reset function setting.
vi. OE: Output enable.
vii. MD1, MD2: Excitation mode setting.
[Setting for External Component Value]
1. Constant Current (100%)
At VREF =0.55V
Iout
=VREF [V] / 5 / RF [Ω]
=0.55 [V] / 5 / 0.22 [Ω]
=0.5 [A]
2. Chopping Frequency
Fchop =Ichop [μA] / (Cchop x Vt x 2)
=10 [μA] / (150 [pF] x 0.5 [V] x 2)
=67 [kHz]
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LV8702V Application Note
Notes in design:
●Power supply connection terminal (VM, VM1, VM2)
9 Make sure to short-circuit VM, VM1 and VM2.For controller supply voltage, the internal regulator voltage
of VREG5 (typ 5V) is used.
9 Make sure that supply voltage does not exceed the absolute MAX ratings under no circumstance.
Noncompliance can be the cause of IC destruction and degradation.
9 Caution is required for supply voltage because this IC performs switching.
9 The bypass capacitor of the power supply should be close to the IC as much as possible to stabilize
voltage. Also if you intend to use high current or back EMF is high, please augment enough capacitance.
●GND terminal (GND, PGND, Exposed Die-Pad)
9 Since GND is the reference of the IC internal operation, make sure to connect to stable and the lowest
possible potential. Since high current flows into PGND, connect it to one-point GND.
9 The exposed die-pad is connected to the board frame of the IC. Therefore, do not connect it other than
GND. Independent layout is preferable. If such layout is not feasible, please connect it to signal GND. Or
if the area of GND and PGND is larger, you may connect the exposed die pad to the GND.
(The independent connection of exposed die pad to PGND is not recommended.)
●Internal power supply regulator terminal (VREG5)
9 VREG5 is the power supply for logic (typ 5V).
9 When VM supply is powered and ST is ”H”, VREG5 operates.
9 Please connect capacitor for stabilize VREG5. The recommendation value is 0.1μF.
9 Since the voltage of VREG5 fluctuates, do not use it as reference voltage that requires accuracy.
●Input terminal
9 The logic input pin incorporates pull-down resistor (100kΩ).
9 When you set input pin to low voltage, please short it to GND because the input pin is vulnerable to noise.
9 The input is TTL level (H: 2V or higher, L: 0.8V or lower).
9 VREF pin is high impedance.
●OUT terminal (OUT1A, OUT1B, OUT2A, OUT2B)
9 During chopping operation, the output voltage becomes equivalent to VM voltage, which can be the cause
of noise. Caution is required for the pattern layout of output pin.
9 The layout should be low impedance because driving current of motor flows into the output pin.
9 Output voltage may boost due to back EMF. Make sure that the voltage does not exceed the absolute
MAX ratings under no circumstance. Noncompliance can be the cause of IC destruction and degradation.
●Current sense resistor connection terminal (RF1, RF2)
9 To perform constant current control, please connect resistor to RF pin.
9 To perform saturation drive (without constant current control), please connect RF pin to GND.
9 If RF pin is open, then short protector circuit operates. Therefore, please connect it to resistor or GND.
9 The motor current flows into RF – GND line. Therefore, please connect it to common GND line and low
impedance line.
44 / 45
LV8702V Application Note
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