An Active Rectifier/Regulator Combo Circuit for Powering Biomedical Implants

摘要

A circuit that combines an active rectifier and a linear regulator, which will be referred to as a rectulator, is proposed in this paper. The main transistor in the rectulator is used for both the rectification of the AC input (V_(AC)) and the regulation of the DC output (V_O) to reduce the overall voltage drop between V_(AC) and V_O. The rectulator has a high power efficiency (ηP) and very good amplitude modulation (AM) rejection on V_(AC) against AC field strength variations. A full-wave rectulator implemented in a 0.18μm CMOS process showed an AM rejection > 45dB for an AM frequency < 2kHz. A ηP of 90.7% was measured for an input frequency of 5MHz, V_O = 2.5V and an output power of 10.5mW.