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[ DRV8303 ] Bulk Capacitance for PVDD

Other Parts Discussed in Thread: DRV8303, DRV8301

[ DRV8303 ] Bulk Capacitance for PVDD

Hi,

The selection of bulk cap for PVDD is always discussion at my customer side. Can anyone help me to understand more about bulk cap selection?

  • DRV8303 for 3 phase BLDC
  • Output power: more than 200W (rated), more than 400W (peak)
  • Peak current: around 30A - 40A
  • PVDD: around 40V

For circuit above, my customer uses 2200uF, but always discuss whether this value is enough or not. (or may be too small)...

I know that the DRV8301 datasheet has some description about Bulk Capacitance, but if someone know further more information, it's really helpful.

Regards,

Ken

  • Hi Ken,

    Our DRV8301 expert has been contacted and should reply soon. The most current DRV8301 datasheet includes a section with general guidelines for bulk capacitance. Because each system is different, it is recommend to confirm the appropriate size with system level testing.
  • Hi Ken,

    Bulk capacitance selection depends very heavily on the application setup. The section at the end of the DRV8301 explains some of these parameters. Ultimately the customer will have to decide this. Simulation can sometimes create a close representation but oftentimes in circuit testing is needed to see what is required.

    Parameters to watch:

    Peak currents

    Power supply type/ESR

    Supply voltage

    Capacitor type/ESR

    Power cable inductance

    Tolerable voltage ripple

    Regeneration currents from the motor

    I think 2200uF is a good starting value.

  • Hi Rick, Nicholas,

    Thank you for your reply. I now understand that no clear guideline we can refer... I will discuss with customer.

    Regards,

    Ken