An active MOS diode with Vth-cancellation for RFID rectifiers

An active MOS diode for low voltage and low power RFID rectifiers is presented. The diode is based on the technique with internal threshold cancellation (ITC) for MOS diodes and uses a simple control scheme to minimize the diode reverse leakage so that full threshold cancellation is achieved. A theoretical background that illustrates the limitations with the ITC diode and a detailed presentation of the proposed diode with a short design procedure is included. The proposed diode is implemented in AMS 0.35 μm CMOS and simulated in Cadense Spectre in a single diode rectifier. With a diode voltage ranging from 50 to 100 mV, the proposed diode simultaneously demonstrates improved voltage and power conversion efficiency of more than 20 % each for frequencies up to 1 MHz, as compared to the MOS diode with internal threshold cancellation.