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DRV8212P: DRV8212P

Michael Jakob
Prodigy 30 points
Part Number: DRV8212P
Other Parts Discussed in Thread: DRV8212

Hi all,

Altought this device seems to be the one I need, I'm struggeling a little bit with the max. PWM frequency of 100kHz. 

Idea: Can one put a high side FET between the power source for the motor voltage and VM, and turn this FET - and therefore the VM voltage - on and off with a frequency of 1MHz instead?

The DRV device I could then still use to switch the motor's direction. 

Thank you very much in advance,

Michael J.

  • 0
    TI__Mastermind 37683 points

    Hi Michael,

    Thank you for your question.

    Unfortunately, witching the power supply at 1MHz will no work due to the awake delay time of 100us. After disconnecting VM, the driver will go into sleep mode and requires a 100us time after power up to start driving the load. Can you provide more clarification on the need for such high frequency and the application? There might be another part in our portfolio that may fit your needs.

    Regards,

    Pablo Armet

  • 0
    Prodigy 30 points

    Hello Pablo,

    I was almost sure that this won't work.

    We would like to precisely drive a low inductance motor (30uH) with an enhanced PWM speed (1MHz). This would enable us to set a more accurate motor voltage and therefore having a better feedback of the measured motor current.

    At the same time, the space on the PCB is very limited and we only have 3.0VDC available.

    If the DRV8212 would allow a PWM frequency of 1MHz this would be the perfect match for our application. Since the datasheet says "only" 100kHz PWM, we came up with the idea described earlier :-)

    Best regards,

    Michael

  • 0 in reply to Michael Jakob
    TI__Mastermind 37683 points

    Hi Michael,

    Thank you for the information.

    Unfortunately is not possible to switch at 1MHz with the DRV8212. 

    Regards,

    Pablo Armet

  • 0 in reply to Michael Jakob
    Genius 5040 points
    Michael Jakob said:
    We would like to precisely drive a low inductance motor (30uH) with an enhanced PWM speed (1MHz). This would enable us to set a more accurate motor voltage and therefore having a better feedback of the measured motor current.

    You always can add more inductance coil in series to the motor.

    Brian

  • 0 in reply to Brian Dang
    TI__Mastermind 37683 points

    Hi Brian,

    A high inductance can help lower the required PWM frequency but a lower inductance motor may e required for certain applications.

    Michael,

    If possible, can you tell me what is the application? Is there a specific reason for the low inductance motor? 

    Regards,

    Pablo Armet