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DRV8832 output status while transitioning forward and reverse

HM
Intellectual 460 points
Other Parts Discussed in Thread: DRV8832

Hi,

I have a question about output status while transitioning forward and reverse on DRV8832.

On my product specification, DRV8832 will be used forward and reverse repeadedly. (forward --> reverse --> forward -->reverse)

While transitioning from forward to reverse (or reverse to forward), I guess both OUT1 and OUT2 NEVER go to following status for a moment.  Is that correct?

(1) OUT1, OUT2 =  L, L

(2) OUT1, OUT2 =  H, H

(3) OUT1, OUT2 =  Z, Z

 

Best Regards,

Hide

  • 0
    TI__Mastermind 26065 points

    Hi Hide

    So, your inputs of IN1 and IN2 are changing directly during transition such as (1,0) ->(0,1)->(1,0)-> .... , right?

    Also you mean test the outputs with motor connected and with above inputs pattern, right?

    As the motor recirculation current and the PWM voltage control of DRV8832 will bring additional effects to the outputs voltage during the transition time, the answer to your questions are actually not so certainty.

    Thanks.

  • 0 in reply to Wilson Zuo
    Intellectual 460 points

    Hi Wilson,

    Thanks for your feedback.

    It was not my product specification, but my customer's...

    I will confirm them tomorrow, but I guess they are thinking that IN1 and IN2 are changing directly during transition such as (1,0) ->(0,1)->(1,0).

     

    Thanks,

    Hide

  • 0 in reply to Wilson Zuo
    Intellectual 460 points

    Hi Wilson,

    Yes, IN1 and IN2 are changing directly during transition such as (1,0) ->(0,1)->(1,0)->

    Output are not connected to the motor.  They are used for switching purpose for AC power supply.

     

    Customer is using uPD16805 for above way to use now.  But, they are looking for replacement device because of discontinue of  uPD16805.  On the uPD16805, outputs go into standby mode during transition such as (1,0) ->(0,1)->(1,0), but it is not a problem for them.  On the other hand, it doesn't go into stop mode during transition.

     

    They concern about "outputs go into stop mode during transition" or not.  If you have any information about on this, please let me know.

     

    Thanks,

    Hide

  • 0 in reply to HM
    TI__Mastermind 26065 points

    Hi Hide

    What is the frequency of the (1,0) ->(0,1)->(1,0) shifting? Because DRV8832 has a internal PWM duty close loop control, it will take about 12 ms for the H bridge invert the driving current direction. So it is not recommended to driver INx too fast.

    Thanks, 

  • 0 in reply to Wilson Zuo
    Intellectual 460 points

    Hi Wilson,

    The frequency of the (1,0) -> (0,1) -> (1,0) is 20kHz.

    On the datasheet of DRV8832, it seems transition time will be about 12ms from brake or sleep to forward or reverse.  Does it take about 12ms from forward to reverse, or from reverse to forward?

    Thanks,

    Hide

  • 0 in reply to HM
    TI__Mastermind 26065 points

    Hi Hide

    Let me check, but if I remember my test long time ago right, this 01 to 10 change will also take the integration time.

    Thanks

  • 0 in reply to Wilson Zuo
    TI__Mastermind 26065 points

    Hi Hide

    Sorry for my late verification, checked that changing from 0,1 to 1,0 or reverse will still take the PWM control loop time.

    Thanks

  • 0 in reply to Wilson Zuo
    Intellectual 460 points

    Hi Wilson,

    As the result of operation test, customer confirmed it works without problems.

    Thank you for your cooperation.

    Hide

  • 0 in reply to HM
    TI__Mastermind 26065 points
    Hi Hide

    I need some correction for this post. Only an accurate complemenary driving from 01 to 10 ... will not triggle the PWM ramping. When I say the accurate, tests shows any >1.5us deadtime or overlap will triggle the PWM ramping state.

    Best regards,