Envelope Tracking Supply Modulator with Trellis-Search-Based Switching and 160-MHz Capability

The hybrid amplifier that combines a buck converter and linear has been widely used as the envelope tracking (ET) supply modulator for ET power (PA) application. Instead of adding more large off-chip passives to raise efficiency amplifier, this work uses Viterbi-like trellis search (TS) digital signal processing (DSP) algorithm find optimal switching sequence in lowering RMS error current op-amp, minimizing switching. For 20-MHz channels, it lowers op-amp by 27%. chip also supports 160-MHz channels without TS. With 802.11ax modulation, raises total 2.5-GHz PA 7.2% at 22.3 dBm, with EVM −32.7 dB.