High efficiency envelope tracking supply voltage modulator for high power base station amplifier applications

Wideband supply voltage modulator with efficiency of 85.1% with 7.5dB PAPR (Peak to average power ratio) (WCDMA, LTE, MC-GSM signals), 120W average output power and 91.7% with 0dB PAPR (GSM applications), 130W output power signals was built. Supply voltage modulator consists of parallel linear amplifier and switching stage. Linear amplifier is controlled by envelope signal, and novel method for controlling switching stage is presented, resulting in high efficiency and low sensitivity to component variations. New control achieved over 20%-unit efficiency improvement in back-off, and measured efficiency was above 80% over 14dB average power range with 7.5dB PAPR test signal. Modulator achieved 20MHz operation fulfilling linearity requirements.