lv8735v ON Semiconductor, lv8735v Datasheet - Page 19

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

(4) Current LIMIT mask function
(5) Current LIMIT mask time (Tcmk)
Only the DCM mode. At STM mode OE pin : It operates as 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.
When the capacitor is not connected, the function of LIMIT in the current can be switched to operation/nonoperating
state by the state of the input of the CMK pin.
The time of the mask of current LIMIT function can be set by connecting capacitor C CMK between CMK pin - GND.
Decide the value of capacitor C CMK according to the following expressions.
Mask time : T CMK T CMK ≈ -C CMK × R × 1n ( 1- Vt CMK / (I CMK × R )) (sec)
1ch operate
2ch operate
current limit
current limit
(capacitor)
CMK
1ch
2ch
“H” or OPEN
brake
mask
mask
CMK
“L”
forward
1.5V
brake
Vt CMK : LIMIT mask threshold voltage typ. 1.5V
I CMK : CMK pin charge current typ. 25μA
R : Internal resistance
forward
release
LV8735V
Current LIMIT function
release
nonoperating
operation
typ. 100kΩ
brake
mask
brake
mask
forward
forward
0.3V
release
release
mask
brake
No.A1848-19/26
mask
brake