High efficiency wideband envelope tracking power amplifier with direct current sensing for LTE applications

A high efficiency wideband envelope tracking power amplifier for LTE applications is presented. The CMOS envelope amplifier with direct current sensing has a measured average efficiency of 78% with a 5 MHz LTE signal. The envelope tracking power amplifier including a GaAs HBT RF stage has overall power added efficiency (PAE) above 46% with an average LTE output power of 27.6 dBm and a gain of 26.5 dB.