VNH5019 min pwm frequency

Hi Folks,
I am trying to drive a Pololu DC gear motor (#2826) with one half of Pololu’s VNH5019.
I am generating the pwm from an Adafruit 16-channel PWM Hat (product # 2327) which is mounted to Ras Pi3 B+. The Pi uses I2C to communicate with hat.

I’ve been able to generate pwm signal and the VNH5019’s Motor Power led is lit, but so far no success turning the motor.

The Adafruit hat has a max pwm freq of 1KHz. The VNH5019 spec reads 0-20KHz, so this should be fine… but could 1KHz be too slow for VNH5019.

My PWM and INA/B lines:

Does anyone have experience with this or similar setup?

Thank you for any input.


I am sorry you are having trouble controlling a motor with your VNH5019 motor driver. In general, a 1kHz PWM is a little low, but should not really be a problem for the VNH5019. Can you tell me more about your system? How are you supplying power? Have you verified that your motor works fine when directly connected to your power supply? If you send a 100% duty cycle signal (i.e. a constant logic high) to the VNH5019’s PWM pin, do you get the same behavior? Can you also post pictures that clearly show your connections and soldered joints?


Thanks very much for response Jon.
It is working now. Based on your suggestions I questioned the non-signal pins.
The problem was that I was using GND/V+ from ADAFruit’s pwm pins to power VNH5019’s GND/VDD. Once I connected VNH5019’s GND/VDD to supply GND/5v all became right in the world.

You were also right about 1KHz PWM working with VNH, it seems fine; I’ve been able to drive at full range of dutyCycles.

Thanks again!

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