lv8740v ON Semiconductor, lv8740v Datasheet - Page 12

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

(7) Forward/reverse switching function
(8) Setting the chopping frequency
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 to
the STP pin. Therefore, when OE is returned to Low, the output level conforms to the excitation position proceeded
by the STEP input.
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.
For constant-current control, chopping operation is made with the frequency determined by the external resistor
(connected to the RCHOP pin).
The chopping frequency to be set with the resistance connected to the RCHOP pin (pin 11) is as shown below.
Excitation position
1ch output
2ch output
High
Low
FR
STEP
FR
(1)
(2)
Counter-clockwise (CCW)
100
80
60
40
20
Chopping frequency settings (reference data)
0
CW mode
0
Operating mode
Clockwise (CW)
(3)
(4)
10
(5)
LV8740V
20
RCHOP – kΩ
(6)
30
CCW mode
(5)
(4)
40
(3)
50
PCA01883
(4)
CW mode
60
(5)
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