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DRV8329-Q1: DRV8329-Q1: Regarding the EMC CE02 issue:

user6354551
Prodigy 230 points
Part Number: DRV8329-Q1


Tool/software:

The chip we are using is ‌DRV8329AQRGFRQ1‌. During EMC conducted emission testing, both the voltage method and current method showed excessive emissions at ‌95.2 MHz‌.
The issue persists even when the motor is stopped. Only when the ‌SLEEP pin of the DRV8329AQRGFRQ1 is disabled‌ does this frequency disappear.

Let me know if you need further assistance!

  • 0
    TI__Expert 6585 points

    Hello,

    Thank you for the information. Usually we do not do EMC testing on a device level, usually this is more of a system level analysis, so please understand that information/support is limited here, but I will try to help.

    Could you provide more information on what you mean by motor is stopped? Does this mean device is powered but you stop switching inputs? 

    Thank you,

    Joseph

  • 0 in reply to Joseph Ferri
    Prodigy 230 points

    The meaning of motor stop is that the SLEEP of the chip is enabled, the charge pump is working, the PWM of the MCU is not emitted, and there is no current in the motor. We believe it may be related to the charge pump.

  • 0 in reply to user6354551
    TI__Expert 6585 points

    Hello,

    It is possible that the charge pump may be the source.

    Is the value seen at 95.2 MHz outside of your specification and therefore you cannot use the chip?

    I'm not sure how much can be done to mitigate this. Can you help me understand if this is a major problem for your system as a whole?

    Thank you,

    Joseph

  • 0 in reply to Joseph Ferri
    Prodigy 230 points

    Hello: As shown in the test graph above, both the peak and average values of 95.2 MHz are exceeded. This chip is used in vehicles, and cars have strict requirements for EMC. Therefore, I would like to know possible solutions.

  • 0 in reply to user6354551
    Genius 3860 points

    Hi,

    I would try to use a small resistor 1-5 Ohm in series with charge pump capacitor.

    Regards,

    Grzegorz

  • 0 in reply to user6354551
    TI__Expert 6585 points

    Hello,

    As mentioned, if the current can stand to be slightly limited you can try a small series resistor. 

    I would also make sure that there is proper decoupling caps local to the DRV.

    Thank you,

    Joseph