2018 Volume 15 Issue 8 Pages 20180206
An asynchronous dual-switch hybrid envelope tracking (ET) supply modulator is proposed in this paper. Two high-efficiency switching amplifiers (SA) working at different speed are adopted to reduce the current supplied by the linear amplifier (LA), which improves the efficiency of the supply modulator. A highly reliable control circuit is presented to make the SAs work asynchronously. Measured with 20 MHz LTE signal, the proposed supply modulator’s average efficiency reaches 86% when the output power is 29.7 dBm. The supply modulator is fabricated in 180 nm CMOS technology with 0.7 × 0.7 mm2 die area.