A CMOS Switched-Capacitor Boost Mode Envelope Tracking Regulator with 4% Efficiency Improvement at 7.7dB PAPR for 20MHz LTE Envelope Tracking RF Power Amplifiers

In this paper, the switched-capacitor boost (SCB) mode envelope tracking (ET) technique with a switched-capacitor circuit and a low dropout (LDO) regulator are used to replace conventional envelope tracking regulators. At a Peak-to-Average Power Ratio (PAPR) of 7.7dB common for LTE communication, the efficiency is 72%, which is 4% higher than the theoretical limit of conventional ET techniques. When PAPR increases from 6.1dB to 7.3dB, the conventional ET efficiency decreases from 82% to 69% whereas the SCB mode increases by 2%.