Use a self-powered op amp to create a low-leakage rectifier

摘要

You can combine a carefully cho-sen op amp, a low-threshold P-channel MOSFET, and two feedback resistors to make a rectifier circuit with less forward drop than a diode (Figure 1). The rectified output voltage powers the active circuitry, so no additional power supply is necessary. The circuit's quiescent current is lower than most Schottky diodes' reverse-leakage cur-rent.