A power-efficient dual-tank FSK demodulator for passive wireless microsystems

A dual-tank FSK demodulator to boost the amplitude of the received signal at FSK carrier frequencies subsequently power conversion efficiency is presented. A fast energy depletion technique is proposed to increase the data rate. In addition, a full-wave quadruple voltage multiplier with low substrate leakage currents is proposed to produce dual-polarity supply voltages required for draining the resonant tanks. Data are recovered by comparing output voltages of the resonant tanks with a preset reference voltage at the beginning of each FSK interval. The FSK demodulator has been designed in IBM 0.13-μm 1.2-V CMOS process. Simulation results show that the power conversion efficiency of the proposed dual-tank voltage multiplier is 30 times that of a corresponding single-tank voltage multiplier while the substrate leakage current of the proposed voltage multiplier is nearly 1000 times smaller than that of conventional voltage multipliers. The proposed FSK demodulator can transmit at 3 Mbps with 5/10-MHz FSK carriers while consuming only a few tens of μW.