This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV8432 boost circuit

Hi,

just wondering: is it possible to drive the GVDD pins of the drv8432 motor driver directly with the high side fet gate voltage and thus bypass the internal boost circuit (if i don't mount the boost cap). And thus get a 0-100% duty cycle range ? Or would this in any way damage the device ?

Kind Regards

Jan

  • Jan,

    High side FET gate  voltage is derived through the Bootstrap capacitor and it is done internal to IC so, how you are going get high side FET gate voltage to drive GVDD pin.Please help me; I am not able to understand your proposal. May be simple diagram should help to understand it better.

     Best Regards

    Milan- Motor Application Team

  • typically the boost circuit is build as above: the boost capacitor is connected to GND by the negative fet-> so charge builds up on the cap. Then the cap is connected is connected to Vmotor by the positive fet so the charge of the boost cap is pushed through the second diode onto the secondary capacitor until the secondary capacitor charge equals Vmotor + GVDD (- diode losses). 

    So i was thinking: can i charge the secondary cap immediately with Vmotor+GVDD at the GVDD pin. But after i send the post i saw in the datasheet that the max voltage for the GVDD pin is 13.2V so i suppose there is other circuitry connected to the pin... 

    Regards

    Jan

  • Jan,

    Ok now I got your idea but as you rightly found out that this will exceed maximum voltage rating of 13.2V so will not be useful. Our motor application team is trying to come out trickle charge circuit to support 100% duty cycle operation with bootstrap configuration but it’s not complete yet. I will get back to you soon with feedback on this circuit.

    Best Regards

    Milan-Motor Application Team

  • Ok,

    thanks for your time.

    Regards

    Jan