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DRV8845: Brake (slow decay) for BDC motor

Kei Kuwahara
Expert 7710 points
Part Number: DRV8845

Hello team,

My customer is considering to use DRV8845 with 4 Brushed DC motors. However, they want to use Brake (slow decay mode).

From the datasheet Table 8-5, there is no Brake statement on the truth table.

Can DRV8845 use Brake mode with BDC motors?

This device is featured with dynamic decay control, which is simillar to mixed decay mode.

How to enable dynamic decay control? Can it be enabled by setting it to coast mode (EN = H)?

Best Regards,

Kei Kuwahara

  • +1
    TI__Mastermind 19790 points

     Hi Kei,

    The DRV8845 does not have slow decay and therefore no specific brake function. The “Coast” function that is on Table 8-5 sends both outputs into Hi-Z. During this time all FETs are in the OFF state and current is decayed through the body diodes of the FETs.

    The smart tune dynamic decay regulates the fast decay percentage of the total mixed decay time to lower current ripple and optimize performance. This mode is set by default to optimize current regulation and does not need to be set.

    Best,

    David