POWER SUPPLY DEVICE, POWER SUPPLY METHOD, PORTABLE ELECTRONIC DEVICE, AND ELECTRONIC WATCH

摘要

A power supply device comprising a first diode connected with one terminal fed with an AC voltage and a high potential side voltage, a second diode connected with the other terminal fed with an AC voltage and the high potential side voltage, a transistor connected between the one terminal and a low potential side voltage, and a second transistor connected between the other terminal and the low potential side voltage. A comparator turns off the second transistor, when no forward current flows through the first diode, and turns off the first transistor when no forward current flows through the second diode, so that an AC electromotive force generated can be efficiently rectified and electric power is fed while suppressing a leakage current to a remarkably low level when no power is generated or the electromotive force is of a small amplitude.