PWM frequency

Gerhard · Joined: 30 Aug 2007 Posts: 144 Location: South Africa

Hi. I am driving 2 - H-bridges via the PWM function of the pic. I am using a frequency of about 800Hz. I need the output to be stable but if i up the frequency to about 5Khz the electronics has a too log propogation time to switch corectly. What is the recomended frequency for a dc motor if using pwm??

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

What H-Bridge chips are you using, and what FETs or transistors (if any) ?
What motors are you driving ?

We used LT1158 Half-bridge drivers with external FETs at 13 kHz, with
no problems. I picked that frequency since it seemed to have the
least amount of audible noise and the highest torque.

Gerhard · Joined: 30 Aug 2007 Posts: 144 Location: South Africa

The mosfets I am using is a IRZ44 and I am using a HIP4081 driver from Intersel. The motors are normal small DC motors that is used in the wiper's of a vehicle.