lv8740v ON Semiconductor, lv8740v Datasheet - Page 17

• Manufacturer Part Number: lv8740v
• Description: Pwm Current Control Stepping Motor Driver
• Manufacturer: ON Semiconductor

DCM Mode (DM-High)
(1) DCM mode output control logic
(2) Reset function
(3) Output enable function
(4) Current limit control time chart
The output ammeter calculation type when the attenuation function of the VREF input voltage is used is as follows.
(Example) When VREF = 1.5V, setting current ratio = 100% [(ATT1, ATT2) = (Low, Low)] and RF resistor = 0.2Ω,
the following output current flows :
Under such a condition, when assuming (ATT1, ATT2) = (High, High).
The reset function does not operate in DCM mode. In addition, the MONI output is High, regardless of the RST pin
state.
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.
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.
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
DC11 (21)
IOUT=(VREF/5)×(Attenuation ratio)/RF resistance
I OUT = 1.5V/5×100%/0.2Ω=1.5A
I OUT = 1.5A×33.3%=500mA
High
High
Low
Low
ATT1
High
High
Low
Low
High or Low
Parallel input
RST
High
Low
OE
Coil current
fchop
Current mode
Set current
DC12 (22)
High
High
Low
Low
ATT2
High
High
Low
Low
CHARGE
Reset operation not performed
OUT1 (2) A
Forced CHARGE
section
Current mode
Operating mode
OFF
High
Low
Low
Operating mode
SLOW
Output OFF
Output ON
Output
Current setting reference voltage
OUT1 (2) B
LV8740V
OFF
High
Low
Low
66.7%
33.3%
100%
50%
High output
CCW (Reverse)
CW (Forward)
MONI
Standby
Mode
Brake
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