Embodiments relate to circuit for reversing a threshold voltage shift of a transistor. The circuit includes a current mirror for sensing a transistor current and generating a mirrored current corresponding to the sensed transistor current, a gate biasing module for providing a gate bias to the transistor, and a calibration engine configured to receive the mirrored current from the current mirror and to control the gate biasing module in response to determining whether the mirrored current is outside of a predetermined range indicative of a shift in the threshold voltage of the transistor. The gate biasing module includes a gate biasing circuit configured to operate the transistor in a region where hot carrier injection (HCI) is present, and a gate switch for coupling the gate biasing circuit to a gate terminal of the transistor.