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DRV8870: Inquiry about DRV8870 operation

JH Shin
Guru 11000 points
Part Number: DRV8870

Hello,

My customer is testing the DRV8870 operation on their custom board.

They designed as below.

  - Sense Resistor = 0.1R, Vref = 3.3V, Current limit setting = 3.3A

It is confirmed that the 3.3A limit is applied to the motor outputs OUT1 and OUT2, and when the current of the motor input VM is measured, it is as follows.

There may be a Toff time in us units after the current limit, but if you look at the graph above, the current turns ON/OFF repeatedly every 200 mS.
(The 200ms cycle is not fixed, but slightly variable)

The actual motor is also turned on and off.

Is this symptom caused by lack of torque in the motor? Or is the DRV8870 limited as above?

Thank you.

JH

  • 0
    TI__Mastermind 18475 points

    Hello JH, 

    The DRV8870 is capable of 3.6 A peak drive whilst this is the following recommendation we give:

    This behavior that you are seeing might be a TSD event and it shuts off. Once it is below the TSD limit, it turns on and it repeats this behavior. If you can try to measure the temperature of the IC to confirm this. You could also lower the current and see if this behavior still occurs.

    Best regards,

    Keerthi Kumanan