A circuit comprises a CLVS, a LEA coupled to the CLVS, and a peak detector coupled to the CLVS and the LEA, wherein the peak detector is a switch-based peak detector. A method comprises closing a first switch for a period of time to provide a current to an actuator, opening the first switch after the period, measuring, after the opening, a voltage associated with the actuator, and determining, based on the measuring and using an ADC, whether a diode is present in the actuator and coupled with a correct polarity, is missing, or is present in the actuator and coupled with an incorrect polarity.