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DRV8701: Vbat (H-bridge) supply higher than VM

Damian Grzesko
Prodigy 20 points
Part Number: DRV8701
Other Parts Discussed in Thread: UCC27288

Hi!

is it possible to have H-bridge voltage higher then power supply voltage on VM pin? We would like to have 60V motor supply and 24V DRV8701 supply. Our idea is to disable OCP, use high side P-channel mosfets controled by N-channel mosfets and a voltage divider on SH1 and SH2 pins. Is it a good solution?

Thanks a lot in advance.

Best Regards

Michał

  • 0
    TI__Mastermind 37683 points

    Hi Damian,

    It is not recommended to have large difference in voltage between the device and h-bridge. I suggest looking into the UCC27288 half-bridge high voltage driver as an alternative solution to using the DRV8701. The UCC27288 does not have OCP which is a feature you are trying to disable in the first place. You can supply the motor up to 120V.

    If you have more question regarding the UCC27288, I suggest posting to the power management forum for further assistance

  • 0 in reply to Pablo Armet
    Prodigy 20 points

    Hi,

    is there any reason to not have a large voltage difference?
    UCC27288 doesn't look like something I was looking for. I need full bridge driver with PWM and current sense feedback.

    Best Regards

  • 0 in reply to Damian Grzesko
    TI__Mastermind 37683 points

    Hi Damian,

    Having different power supplies for the device and the H-bridge can cause OCP to not trigger on the HS FETs. The OCP circuitry monitors the VDS of each FET and once it detects the VDS voltage go above 1V for 4.5µs, an OCP fault will be triggered. Below is the block diagram of the OCP circuitry. You can disable the HS VDS OCP monitoring (when using different power supplies) by tying IDRIVE to AVDD as mentioned in Table 6 of the DRV8701 datasheet.