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DRV8880 Charge pump voltage at failure using

masahiko shimizu
Guru 11235 points
Other Parts Discussed in Thread: DRV8880

Hi,

Could you give me advice for customer support, please?
Customer had a mistake.
Detail is show at attached file.

Customer connected charge pump capacitor between VCP pin and 3.3V.
But motor could drive normally.
Customer confirmed the charge pump capacitor votage, then it is 40V.
VM of customer system is 33V.
Do you know why the charge pump capacitor voltage become to 40V?

*Ofcause, this mistake has revised yet.

Best regards,
Shimizu

DRV8880.pptx

  • 0
    TI__Mastermind 26065 points

    Hi Shimizu,

    The VCP voltage will be about VM + 10 normally. And it is possible that no matter where you put the VCP cap in the system power lines, such as GND or VM or V3P3,  it will still working. Because in the system there are caps from VM to GND, V3P3 to GND, so finally there will be a equivalent cap to VCP pin to do the filter and storage function of the VCP internal switching.

    But this must be corrected  to meet the spec for a long term stable running.

    Best regards,