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DRV8829: VM-VCP resistance.

Guru 11255 points
Part Number: DRV8829

Hi team,

Doesn't it mean that the high-side FET cannot be turned off not only during power-off / sleep but also during normal operation?
This post says that this resistor is only valid in power off and sleep modes.

Sincerely.
Kengo.

  • Kengo-san,

    Rick said, "the 1Mohm bleeds the charge pump capacitor. This will prevent the outputs from being shorted during power off or sleep modes, allowing the motor to turn freely. If you do not need this feature, the VCP cap will eventually discharge and the motor will begin turning."

    During power off or sleep mode, the device shuts down the internal circuit. The FET control logic is also shut down. 1Mohm can discharge the VCP capacitor before the FET control logic loss power.

  • Wang-san,

    Thank you for your reply.

    Does the VM-VCP resistor work when the power is turned on?
    In other words, when the power is turned on, the gate signal is surely turned off, so I think there is no possibility that the FET cannot be turned off.

    Sincerely.
    Kengo.

  • Kengo,

    You are right. After the device is turned on, the gate is under control and can be turned off, no matter has or not has this 1Mohm. The 1Mohm should be turned off if not power off or sleep mode,