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DRV8212: VCM coil driver for focus control

toshi-e2e
Genius 4850 points
Part Number: DRV8212
Other Parts Discussed in Thread: DRV8411, DRV8210, DRV8210P, DRV8410,

Tool/software:

Hi all,

I am considering a 2-channel H-Bridge motor driver for camera focus control.
The package needs to be as small as possible and be able to operate on around 3V to 5V, with a VCM coil driven by a PWM input.

Are there any motor drivers that meet these requirements?
It's also important that there is no nonlinear behavior when changing the PWM from -100% to +100%.
Thanks in advance.

Regards,
Toshi

  • 0
    Genius 4850 points

    Hi all,

    There is a correction in the application.
    It is for both camera focus and image stabilization like IBIS.

    Regards,
    Toshi

  • +1 in reply to toshi-e2e
    TI__Mastermind 47835 points

    Hi Toshi-san,

    Thanks for your post. If the current requirements are in the 1 A or lower range the DRV8210 or DRV8210P could be used or the DRV8410, DRV8411 (A) for a dual H-bridge in a single package.

    toshi-e2e said:
    It's also important that there is no nonlinear behavior when changing the PWM from -100% to +100%.

    Generally the duty cycle relationship between input to output is very close to each other. Due to slew rate the minimum granular level for example between 1 to 10 % and around 90 to 100 % may not have the same level of linearity as between 10 % to 90 % duty cycle. This is a common behavior with almost all PWM drivers. The drivers with higher SR (fast RISE and FALL times) would be better at the end of the scales but not commonly found in BDC drivers. I hope this helps. Thank you.

    Regards, Murugavel 

  • 0 in reply to Murugavel4637
    Genius 4850 points

    Hi Murugavel -san,

    Thank you for your reply and suggestion.

    Is it correct to understand that the linearity of the PWM duty ratio deteriorates around 1-10% and 90-100% due to the influence of the slew rate, but that there is no nonlinear operation?

    Thanks and Regads,
    Toshi

  • +1 in reply to toshi-e2e
    TI__Mastermind 47835 points

    Hi Toshi-san,

    Yes this is correct. The PWM duty cycle input to output fidelity could be affected by SR, dead-time and propagation delay. SR impacts lower and higher duty cycles only. The propagation delay tPD 135 ns TYP impacts both the rising and falling edge equally for all duty cycles, so there won't be any change to the output duty cycle because of this tPD. The dead time extends the on time and the total on and off time period, so this would result with a slight modification with the duty cycle itself. However, this would be a constant value. The DRV8212 has a fixed dead time of 500 ns TYP. No non-linearity is expected with the switching vs. PWM duty cycle input. 

    Regards, Murugavel