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DRV8701: over current protection of high side FET

Part Number: DRV8701

We would like to use the DRV8701. The question is:
The built-in "overcurrent monitor" protects especially the high side FET. We require at least two different cut-off limits for our application (for example 1A and 3A). Due to our system architecture, we can not guarantee that the voltage VM will always drain via the shunt resistor. It is also conceivable that the current flows from VM via the high side FET directly to the ground. How does the DRV8701 know, at which current the used highside FET is destroyed, so that it is switched off before?
Thank you for your response.
F. Giesen

  • Hi Franz,

    The FET overcurrent monitor measure the VDS of the active FET, and disabled the FET in the event the VDS is above the preset value. The DRV8701 reacts to voltage and not current.

    There is a second overcurrent monitor that measures the voltage across the shunt resistor.

    If you can flow the current through the shunt resistor, adjusting VREF can limit the current using the current regulation. If not, you may need to add external circuits.