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DRV8412: External bootstrap supply for 100% duty cycle operation

Tilen Sluga
Prodigy 145 points
Part Number: DRV8412
Other Parts Discussed in Thread: DRV8876, DRV8873, DRV8874, DRV8256

Hi TI,

We would like to use the DRV8412 in a 100% duty cycle operation and if possible we would like to avoid the min. 50ns pulse for the bootstrap capacitor charging. Would it be possible to use an external power supply tied to the BST_X pin instead of the bootstrap capacitor?

If this would be an option I have a few questions regarding the implementation:

- would the external bootstrap supply need to track the GVDD_X supply in order to maintain the boot voltage above the min. BST_UVP voltage (~7V)?

- a simpler implementation of the above would be a fixed voltage above the GVDD_X and maybe just some current limiting resistors on the BST_X pin? Would this be possible?

- or do you have any other suggestions for using the DRV8412 in 100% duty cycle mode?

Thank you,

Tilen

  • 0
    TI__Guru 55605 points

    Tilen,

    Is there a specific reason why you want to use the DRV8412?  We have many new parts with charge pumps that support 100% with no issue and can do the same or more power. Please let me know your requirements and I can direct you to a newer part.  

    Regards,

    Ryan

  • 0
    Prodigy 145 points

    Hi Ryan,

    We would use the DRV8412 as an normal dc motor driver but would also like to use it for general load switching without PWM.

    Yes, I would be very interested in your sugestions on newer parts with the same or even better power capability and charge pump.

    Tilen.

  • +1 in reply to Tilen Sluga
    TI__Guru 55605 points

    Tilen,

    You didn't provide your voltage range, so I am not sure if the following will work.

    DRV8873 would be my first recommendation for a similar power capability.  If lower power is OK, you can consider the DRV8874 or DRV8876.

    DRV8256 can be considered if you need higher voltage...up to 50V.

    Regards,

    Ryan