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DRV8718-Q1: PWM control mode - external current sense

Piotr F.
Intellectual 2910 points
Part Number: DRV8718-Q1

Hello Experts,

please consider DRV8718-Q1 application - device drives 4 motors  - all in full bridge mode, with half bridge banking: 3 x HB_PWM on one side and 1 x HB_static on another side.

Motors do not drive in the same time.

Custoemr needs to measure 70A peak current with 0.5% accuracy.

Is it possible to measure current with high accuracy in GND (low side sensing) when we control with PWM?

Or is only inline-shunt sensing the option?

Customer so far assumes that low side sensing will not work, because during freewhiling current is not floating via Top or Bottom resistor.

But maybe you have some idea how to measure current with high accuracy in GND during PWM? 

I have not found clear confirmation in TI app notes/other records on this...

  • 0
    Genius 5040 points
    Piotr F. said:
    please consider DRV8718-Q1 application - device drives 4 motors  - all in full bridge mode, with half bridge banking: 3 x HB_PWM on one side and 1 x HB_static on another side.

    Is the device DRV8718 or 8714 (8 or 4 channels)?

    What do you mean of this " 3 x HB_PWM on one side and 1 x HB_static on another side."? Maybe posting a schematic to clarify this better.

    Brian