A 1 GHz frequency-controlled class E2 DC/DC converter for efficiently handling wideband signal envelopes

In this paper, a 1 GHz class E² DC/DC converter, implementing a frequency-modulation (FM) control, is proposed for efficiently handling wideband wireless signal envelopes. Properly terminating the inverting and rectifying GaN HEMT devices, a nearly linear output voltage versus switching frequency profile is obtained, with 70% efficiency at a voltage value 5.1 dB below the peak. Incorporating a Voltage Controlled Oscillator (VCO) and a gate-driving amplifier, the large-signal bandwidth (BW) and slew rate have been estimated to be around 20 MHz and 720 V/μSeg, respectively. The FM converter is also shown to offer a good dynamic reproduction of 6.6 dB peak-to-average power ratio (PAPR) 2- and 4-carrier WCDMA envelope signals, with average efficiencies over 60%. Employed as envelope modulator in a pure polar architecture, handling a 5 MHz hole-punched multisine signal, a 6.7 W output power has been obtained with a transmitter efficiency of 56%.