A novel low-drop CMOS active rectifier for RF-powered devices: Experimental results

We present, in this paper, a new full-wave rectifier topology. It uses MOS transistors as low-loss switches to achieve a significant increase in overall power efficiency and reduced voltage drop. The design does neither require an internal power source nor an auxiliary signal path for power delivery at startup. The highest voltages available in the circuit are used to drive the gates of selected transistors to reduce the leakages and to lower their channel on-resistance, while having high transconductance. The proposed rectifier was characterized with the SpectreS simulator under the Cadence environment and then fabricated using the standard TSMC 0.18 μm CMOS process. The proposed full-wave rectifier is particularly relevant for wirelessly powered applications, such as implantable microelectronic devices (IMD), wireless sensors, and radio frequency identification (RFID) tags. When connected to a sinusoidal source of 3.3 VAC nominal amplitude, it allows improving the power efficiency by 10% and the average output voltage by 16% when compared to other published results.