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DRV8432EVM gives out 5V signal, but not 3.3V

Other Parts Discussed in Thread: DRV8412

Hi,

We have been experimenting (rather successfully), with a few DRV8432EVM boards, on DC brushed as well as stepper motor control. We have seen that you have designed in a 5V regulator on the board, as well as put in a 3.3V regulator, but bring out ONLY the 5V signal. While the 3.3V signal is actually used to light up the OTW and FAULT LEDs, the 5V is just being brought out on the 30-pin header while the 3.3V supply is not.

Please correct me if my understanding is wrong. Otherwise, why is the 5V signal there? Why is the 3.3V signal not brought out?

Would you like to take this feedback for future revisions of the EVM board?

Thanks!

  • Anup,

    Your observation is right. I guess the reason not to bring 3.3V is to avoid external loading on 3.3V because it is used in the EVM for driving LED4, FAULT and OTW.  5V is provided for external I/O interface and DRV8412 inputs are compatible 5V logic. Are you facing any particular hurdle in your application because 3.3V is not brought out to connector J1?

     Best Regards

    Milan-Motor Application Team

  • Milan,

    Thanks for the confirmation! No, it is not really a hurdle, but we were planning to build a simple (shield like/boosterpack style) board for MSP430 as well as C2000 controllers so that we don't need to keep re-wiring the board for different experiments. While doing that we thought of the ability to pull 3.3V supply from the DRV8432EVM itself. But, since there is only a 5V supply, we plan to use that to get our 3.3V supply.

    This was just a curious query because we saw that the 5V supply was completely unused! And, TI's controllers (as much as I know), all run on 3.3V, rather than 5V! Also, maybe you could also consider bringing out the 3.3V supply to J1 and replace the regulators with maybe 250-500mA versions! Although, with the MSP430, even the current one might be sufficient to drive the logic states for the DRV8432.

    Thanks,

    Anup

  • Anup,

    Good point. Yes, if 3.3V is available at J1, it can be used to power external low power micro-controller such as MSP430 and in few cases C2000 also.

    I will give this feedback to EVM design team to bring 3.3V out at J1.

     Best Regards

    Milan- Motor Application Team

  • Hi Anup, I was just wondering, do you want a mass production solution of using this EVM with an external micro that uses 3.3V?  Or is this only for a small number of boards?  If it's for a small number, maybe it won't be a problem to add a wire connection to C6.

    Best regards,
    RE