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DRV8834EVM: Connecting xISEN directly to ground

Jeston Mitchell
Prodigy 80 points
Part Number: DRV8834EVM
Other Parts Discussed in Thread: DRV8834

Hello All,

I have a couple questions in regards to the DRV8834...

1) If xISEN is connected directly to ground, what will the current limit be for each bridge? The datasheet says the following:

  • If current control is not needed, the xISEN pins may be connected directly to ground. In this case, TI also recommends connecting AVREF and BVREF directly to VREFO.

Is the current completely unregulated at this point? Or is there still over current protection equal to the 1.5A RMS output current rating? The datasheet also mentions:

  • Overcurrent protection does not use the current sense circuitry used for PWM current control, so functions even without presence of the xISEN resistors.

2) Can the current consumption of each motor be measured through the xISEN pin? If so, what is the relation between the voltage on the pin and the current consumption of the motor?

Thanks,

Jeston

  • 0
    TI__Guru** 114905 points

    Hi Jeston,

    1) The DRV8834 has overcurrent protection even if the xISEN pins are connected to ground. The overcurrent Iocp is listed as a minimum of 2A. As mentioned in the datasheet, the overcurrent is always actvice. It cannot be disabled.

    2) Instantaneous current can be measured using the voltage across the xISEN resistor. This is valid when current is flowing from VM to  GND. If the current is being recirculated using slow decay, the reading is not valid.