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Original question:

DRV8353R: Increasing gate drive current

DRV8353R: Parallel DRV8353

Kurt Staubli
Prodigy 20 points
Part Number: DRV8353R

Hello

We have developed a hardware with 4 DRV8353H. Each drives one BLDC. One MCU controls all 4 DRVs. It works fine so far.

We would like to use the same hardware without any changes but drive higher currents for more powerful BLCDs. To achieve it, we would drive 2 DRVs with the same PWM. Of course, the software in the MCU would change.

A similar problem was described here: https://e2e.ti.com/support/motor-drivers/f/38/t/781026 , but we do not use one DRV to drive many parallel FETs we control two DRVs with the same PWM and the DRVs drives their H-Bridges which drives one BLDC.

My question: Would this be a problem for DRV8353H? The propagation delay (tPD, INHx/INLx transition to GHx/GLx transition) is according datasheet 200ns typically, no min max is given. Would it be possible to provide the missing numbers? If the transition time differs much, one DRV8353H’s FETs would drive the full current on their own, rather than contribute it equally. The PWM’s frequency is 48kHz and we use 3xPWM-Mode.

Regards,

Kurt

  • 0
    TI__Guru 65220 points

    Kurt,

    Thanks for posting on the MD forum!

    We do not recommend using multiple DRV to drive the same motor. Instead it would be best to use multiple parallel FETs on the output to carry the bridge current as you mentioned.

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    Prodigy 20 points

    Hi Adam

    Thank you for your quick answer.

    Your suggested solution implies that must design a new hardware. If we can use DRV parallel, we can use the same hardware for a rare use case.

    Could you tell me why you recommend not to drive the same motor with multiple DRVs? We have other products with other DRVs and use this mode.

    Regards,

    Kurt

  • 0 in reply to Kurt Staubli
    TI__Guru 65220 points

    Kurt,

    You can try this, it's just not recommended from my side.

    My thought is that it is much simpler and more efficient to drive higher current through one bridge instead of dealing with the parasitics/losses/timing of two complete DRV/bridge combinations.

    Regards,

    -Adam