Current monitoring scheme for low-side body current sensing of vertical power field effect transistor

Abstract

A current monitoring scheme for a power FET configured as a low-side power switch in a power stage enables measuring or sensing of the body diode current flowing in the low-side power-FET when the low-side power FET is being operated in the body conduction mode. In some embodiments, the current monitoring scheme uses a smaller size sense FET for sensing the channel current as well as the body diode current flowing in the low-side power FET. A gain circuit is incorporated to adjust the gain of the sense current so that the channel current sensing and the body diode sensing are scaled to the same gain level to be provided as the monitor current output signal.

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