lv8735v ON Semiconductor, lv8735v Datasheet - Page 18

• Manufacturer Part Number: lv8735v
• Description: Bi-cmos Lsi Pwm Constant-current Control Stepping Motor Driver
• Manufacturer: ON Semiconductor

DCM Mode (DM-High)
(1) DCM mode output control logic
(3) Current limit reference voltage setting function
(2) Blanking time switching 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.
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.
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
The formula used to calculate the output current when using the function for attenuating the VREF input voltage is
given below.
Example : At VREF of 1.5V, a reference voltage setting of 100% [(ATT1, ATT2) = (L, L)] and an RF resistance of
Only the DCM mode. At STM mode RST pin : It operates as RESET function.
(Current limit control time chart)
DC11 (21)
High
High
Low
Low
ATT1
High
High
Low
Low
Parallel input
High
BLK
Low
0.5Ω, the output current is set as shown below.
If, in this state, (ATT1, ATT2) has been set to (H, H), Ilimit will be as follows :
Ilimit = (VREF/5) /RF resistance
Ilimit = (VREF/5) × (attenuation ratio) /RF resistance
Ilimit = 1.5V/5 × 100%/0.5Ω = 0.6A
Ilimit = 0.6A × 20% = 120mA
DC12 (22)
High
High
Low
Low
Coil current
fchop
Current mode
ATT2
High
High
Low
Low
Set current
OUT1 (2) A
OFF
High
Low
Low
CHARGE
Current setting reference voltage attenuation ratio
Blanking time
2μs
3μs
Output
Forced CHARGE
section
Current mode
OUT1 (2) B
SLOW
LV8735V
OFF
High
Low
Low
100%
80%
50%
20%
CCW (Reverse)
CW (Forward)
Standby
Mode
Brake
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