A Class-G Supply Modulator and Class-E PA in 130 nm CMOS

Abstract

A class-G supply modulator utilizes parallel low- dropout (LDO) regulators that are controlled by comparators and negative feedback. It optimizes the power consumption of a nonlinear power amplifier (PA) operating with supply modulation, such that it draws current from one of multiple appropriately sized supply voltages as determined by the input signal envelope. The class-G modulator is used in conjunction with a class-E PA operating in an envelope elimination and restoration (EER) mode to efficiently amplify signals with large peak-to-average ratios. The measured maximum output power and power added efficiency (PAE) are 29.3 dBm and 69%, respectively. The class-G technique is demonstrated for a 64 QAM, OFDM input signal (symbol period = 4 mus) wherein the measured error vector magnitude (EVM) is 2.5% and the average efficiency of 22.6%.