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DRV8300-Q1: Is it possible to use motor driver as GPIO?

JONGYEON BYEON
Prodigy 30 points
Part Number: DRV8300-Q1
Other Parts Discussed in Thread: DRV8300, DRV8328

Tool/software:

Hello.
I'm a DRV8300 three-phase motor driver
The two phases are used to control the normal DC motor by PWM.
I use GHA and GLA, GHB and GLB.
My question is, if you give PWM to 100%, the motor won't rotate. 255 and 0. But if you set it to 255 and 1, it will rotate, but this isn't 100%, right?

The second question I want to give you is not PWM, but when I give SET, CLEAR as GPIO, it doesn't rotate. After all, it's the same situation as not rotating at the first PWM 100%.

Is it supposed to be like this?

  • 0
    TI__Genius 12231 points

    Hi Jongyeon, 

    Thank you for posting to our forum! 

    JONGYEON BYEON said:

    My question is, if you give PWM to 100%, the motor won't rotate. 255 and 0. But if you set it to 255 and 1, it will rotate, but this isn't 100%, right?

    That is correct - The DRV8300 is not capable of running at 100% duty cycle due to the bootstrap architecture implemented without a supporting trickle charge-pump.

    JONGYEON BYEON said:
    The second question I want to give you is not PWM, but when I give SET, CLEAR as GPIO, it doesn't rotate. After all, it's the same situation as not rotating at the first PWM 100%.

    Yes, if the "SET" command is telling the driver to run at 100% duty cycle, then this will also not work.   

    You may need to setup your own function to tell the driver to operate at 98-99% duty cycle instead if that works for your application.

    Best Regards,

    -Joshua

  • 0 in reply to Joshua Maize
    Prodigy 30 points

    Thank you for your answer.
    Are you saying that DRV8300 cannot operate by simply giving a full (SET 5V) signal to the input end because it is a structure without a charge pump??
    You mean the maximum threshold is 98-99%. Did I get that right?

  • +1 in reply to JONGYEON BYEON
    TI__Genius 12231 points

    Hi Jongyeon, 

    That is correct, as bootstrap architecture requires the low-side FET of a phase to at least turn on once per cycle for a minimum time in order to sufficiently charge the bootstrap capacitor; however, devices using a charge pump, or a bootstrap architecture with integrated trickle charge-pump can operate at 100% on. 

    For example, please see our DRV8328 BLDC gate driver that uses bootstrap architecture with a trickle charge-pump (https://www.ti.com/product/DRV8328#features) 

    For further information on this consideration, please refer to section 2.8 of this BLDC driver guide here: https://www.ti.com/lit/an/slvaes1a/slvaes1a.pdf?ts=1731019655470&ref_url=https%253A%252F%252Fe2e.ti.com%252F

    Thank You and Best Regards,

    -Joshua