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DRV8316C: Delay time

Zeming Kong
Expert 3515 points
Part Number: DRV8316C

Hi team,

Below waveform in datasheet shows a 2us delay between INx and SOx, with 200V/us slew rate, it is much longer than parameter giver by datasheet.

Could you please let me know the reason?

Also, I can see some pulse noise in SOx waveform, seems to be caused by INx on/off, will it be a problem?

Best regards,
Zeming 

  • 0
    TI__Expert 3515 points

    Below are the waveforms we tested. It shows a shorter delay, for <1us.

    And noise in SOx, even no INx switches.

    Best,
    Zeming

  • 0 in reply to Zeming Kong
    TI__Genius 17416 points

    Hey,

    Thank you for your question. I have assigned a team member to support your thread.

    Best,

    Akshay

  • 0 in reply to Zeming Kong
    TI__Mastermind 20815 points

    Hi Zeming,

    Thank you for your questions! Could you provide a waveform showing SOA, INHA, INLA, and OUTA? I want to see what is occurring on OUTA during this switching.

    Regards,

    Anthony Lodi 

  • 0 in reply to Anthony Lodi
    TI__Expert 3515 points

    Hi Anthony,

    We checked the datasheet again, and this waveform comes from a DRV8316CR circuit, can I consider the delay compensation is activated so delay is longer? 

    Best,

    Zeming

  • +1 in reply to Zeming Kong
    TI__Mastermind 20815 points

    Hi Zeming,

    There could be a few things at play here in figure 9-6.

    1. Compensation delay could be a factor as you mentioned, though I can't say for sure if it was enabled or not for the waveform. 

    2. It is also important to consider the propagation delay from the inputs changing to the OUTx starting to change.

    3. The device deadtime must be considered as well, which is inserted in between turning off the high side FET and turning on the low side FET (or vice versa)

    4. There is some propagation time for the outputs of the CSAs to change with a change of the input. 

    All these factors results in the 2us delay that is seen between the inputs changing and the CSA output changing. It is also possible that the waveform wasn't taken using the highest slew rate (200V/us), which could add even more time. 

    Let me know if you have any other questions!

    Regards,

    Anthony Lodi