A low-power CMOS voltage boosting rectifier for wireless power transfer applications

The area of applications for wireless power transmission is increasing rapidly, so is the need for designing efficient rectifiers to convert an AC voltage signal to a DC voltage to deliver to the load. In a wireless power transfer module, rectifier, being one of the most important components, needs to be designed in an optimized manner to provide high DC output voltage with a high efficiency from a low RF input power. In this paper, a 10-stage rectifier design using Schottky diodes and poly2 over poly capacitors in 0.5 μm standard CMOS process is presented. Simulation results show that the rectifier can convert an RF signal with an input voltage of as low as 100 mV at 7.2 MHz frequency to an output voltage of 160 mVDc. It achieves 1.55 Vdc signal for an input ac signal of 200 mV. This performance verifies the integration of the rectifier to the wireless power transfer module that would improve the overall power conversion efficiency.