H bridge driver with floating ground help

Thread Starter

santini

Joined Nov 14, 2008
4
Hi all,

I'm trying to use a IRS21094 to drive a H bridge with a PWM input as show in anex below.

I'm using two differents sources. One is +12V between Vcc and Vss and another is +90V between drain of top MOSFET and COM.

If I connect COM and Vss, the circuit works without error, but to avoid spikes and noise from motors, I want to disconnect the two grounds. When I disconnect COM and Vss, the circuit stops to work.

I think that when I disconnect the grounds, the circuit stops because of the absolute maximum ratings says that Vcc must to be between -0.3V and 25V of COM and this isn't true in my circuit.

Any help?

Thanks
 

Attachments

Thread Starter

santini

Joined Nov 14, 2008
4
Hi thingmaker3,

I'm using a electrolytic 1uF, and a ceramic 100nF for any IC. They are really close of ICs irs21094. This don't solve my noise problems.

Thanks
 
Top