High efficiency GaN switching converter IC with bootstrap driver for envelope tracking applications

In this paper, we report a DC/DC converter based on GaN HEMT's with a switching frequency of 200 MHz that can be used to generate envelope-modulated power supply voltages for use in envelope tracking power amplifiers. The converter consists of switching circuits using 0.25-um GaN HEMTs, inductor, and low pass filter, and can provide output voltages above 28V. An integrated bootstrap driver of the switching circuits is employed in order to reduce DC power consumption of the driver stage. Generation of envelope power supply voltages for 20 MHz LTE signals was demonstrated using 200 MHz switching rates with efficiency of 73%(including dissipation in final and driver stages). The chip size is 1075×990 um2.