Monolithic Power Systems, Inc.
HIGH VOLTAGE CURRENT SENSING CIRCUIT WITH ADAPTIVE CALIBRATION

Abstract:

A current sensing circuit for sensing a current flowing through a current sense resistor, wherein the current sense resistor is configured to receive a variable power input voltage. The current sensing circuit includes: a current sense amplifier having a first input terminal configured to be coupled to a first terminal of the current sense resistor to receive the power input voltage, a second input terminal configured to be coupled to a second terminal of the current sense resistor, and an output terminal for providing a current sensing signal indicative of the current flowing through the current sense resistor; and a calibration circuit configured to be coupled to the first input terminal of the current sense amplifier. The calibration circuit is configured to convert the power input voltage into a calibration current, and provide the calibration current to the current sense amplifier, so as to reduce a change in the current sensing signal caused by a change in the power input voltage.