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Original question:

DRV8823: V3P3 power up delay at -5 degree C

DRV8823: No current output when doing Low temperature test

Amelie Zheng
Genius 10865 points
Part Number: DRV8823


Hi Team,

 My customer now use DRV8823 in Car infotainment.However, met the low temperature problem.

They have made 200 sample machine and found that 16 pecs have this problem.

When temperature is -20/-36/-40℃, there are no output current.

Even reset this DRV8823, it stll has no output current;

Only power down VM and then power up again VM, it has output current again...

May I ask is it because OCP or TSD? Do you have some advice to solve this problem?

Thanks!

  • 0
    TI__Guru** 114905 points

    Hi Amelie,

    This appears to be an overcurrent condition or thermal shutdown. The more likely cause at low temperatures is overcurrent.

    The DRV8823 overcurrent trip point is 1.5A minimum for 2.5us minimum.

    What is the decay mode setting?

    What current is flowing through the outputs at -20/ -36 / -40C?

    Is the same motor used for all 200 pieces?

    Please ask the customer to measure the current through the output in the 5us prior to the outputs being disabled.
    This should help provide some insight.

  • 0 in reply to Rick Duncan
    TI__Genius 10865 points

    Hi Rick,

    Thanks for your update. I have asked customer to do more test. And will update the process later. And here are another information.

    1) SPI, A / B / C / DOUT / RESET / SLEEP / SSTB voltage ok at low temperature, low-temperature startup waveform is as follows, and there is no change in timing at normal and low

    2) A / B / C / DOUT output is 0 when not starting at low temperature
    3) DRV8823 circuit as shown below


    4) At present, it can be confirmed that at low temperature, when the DRV8823 has no output current, restart the VM voltage (disconnect and reconnect), and the 8823 output is normal. But reset RESET does not make DRV8823 start normally
    5) Peak working current of stepper motor is 860mA at low temperature

  • 0 in reply to Amelie Zheng
    TI__Guru** 114905 points

    Hi Amelie,

    4) At present, it can be confirmed that at low temperature, when the DRV8823 has no output current, restart the VM voltage (disconnect and reconnect), and the 8823 output is normal. But reset RESET does not make DRV8823 start normally

    Can you clarify the above statement?

    When restarting VM and resetting through RESET, are serial commands re-sent to enable the outputs?

    Also, is it possible the VM voltage is dropping below UVLO on some boards?

    I do not see any capacitors on VM, and I see 18V at 13V in one scope plot.

    In my opinion, this appears to be something that is marginal

    Please ask the customer to look for differences (voltages and currents) on a working board and non-working board.