Tool/software:
I'm applying a 15 kHz PWM signal with 20% duty cycle to IN1 of the DRV8251A, while keeping IN2 LOW.
The motor is connected to the output, but I'm not seeing any movement. However, if I connect one motor wire to OUT1 and the other to GND, the motor does spin.
Could you help me understand what's going wrong?
Input (Yellow IN1, Blue IN2)
Output (Yellow OUT1, Blue OUT2)
Hello,
When IN1 is PWM and IN2 is low, the outputs are switching between a Forward and Coast (Hi-Z) state. I would recommend holding IN1 high and PWM on IN2, doing this will switch the outputs between a Forward and Brake state. This method is preferred as it puts the outputs in a known state while current is recirculating during the off time.
Please see the following app note for more info on current recirculation. Also review section 8.4.1 Bridge Control, and Table 8-2. H-Bridge Control in the datasheet.
Best,
David
