Hello All About Circuits Community, I am Emmanuel Katto.


I'm currently working on a project that involves controlling a DC motor using an H-bridge driver, but I'm running into some issues and could use your expertise.

1. What are the common pitfalls to watch out for when designing a DC motor control circuit with an H-bridge?
2. I’m using PWM to control the speed, but the motor behavior is erratic at lower duty cycles. What could be causing this, and how can I fix it?
3. Are there specific components or configurations you recommend to ensure smooth operation and prevent potential damage to the motor or driver?

Any guidance or advice would be greatly appreciated!

Thanks!
Emmanuel Katto

 

Without more information to work with, I could write volumes on what might be causing the problems on you motor control circuit. Can you be a little more specific please?
What is the size of the motor?
What kind of power supply and what voltage is being used for the motor?
What is generating the PWM signal and how is it powered?
Can you draw a diagram of the power supply wiring for the whole system?
Do you have an oscilloscope? If so, can you show the erratic waveforms at the motor?

 

You should add appropriate flyback diodes across each transistor in the H-bridge to protect against high voltage spikes.

 

Second Keith's questions & request for details!
e.g. Is any of it self built or off-the-shelf?
Schematics needed.