A self-protected, high-efficiency CMOS rectifier using reverse DC feeding self-body-biasing technique for far-field RF energy harvesters

Abstract

A CMOS rectifier is presented for the far-field RF energy harvesting (RFEH) system based on the differential-drive cross-coupled bridge (DDCCB) structure. A novel body-biasing technique known as the reverse DC feeding (RDCF) self-body-biasing technique is proposed for allowing both NMOS and PMOS transistors in the rectifier to operate with a scalable threshold voltage. As such, the RDCF technique enables the rectifier to operate with adaptive efficiency leading to better system performance. The performance of the proposed structure has been verified through simulation using a triple-well 130 nm CMOS technology and analyzed with the conventional source-to-body and the lower DC feeding (LDCF) technique at the operation frequency of 953 MHz along with a corresponding load of 2 kΩ, 10 kΩ, and 50 kΩ. Compared with other published works, the proposed DDCCB rectifier with the RDCF technique has an improved peak PCE of 72.2 % at the frequency of 953 MHz when driving a 10 kΩ load. The RDCF technique also has the capability of self-limiting output DC voltage which is crucial when the rectifier operates at a short communication range. A limit-voltage level of 4.2 V is obtained irrespective of the load to protect the other subsequent circuit driven by the rectifier.