A 200MHz Bandwidth 84% Peak Efficiency AC-Coupled Envelope Tracking Supply Modulator with 10MHz Constant Switching Frequency

Envelope Tracking (ET) is widely used to improve the efficiency of linear power amplifiers (PAs) in mobile handsets. Power dissipation caused by the large peak-to-average power ratio (PAPR) can be reduced by adjusting the RF PA supply voltage according to the transmitted signal's envelope. The conventional analog ET supply modulators (SMs) are usually composed of a high-efficiency switching power modulator (SPM) and a wide-bandwidth linear amplifier (LA). The ET bandwidth is mainly determined by LA and has been extended from 20MHz to 130MHz [1]–[3]. To accommodate 5G New Radio (NR), wide-bandwidth ET SMs are required, but the large PA decoupling capacitor and output voltage exceeding 5V remain bottlenecks [4]. Digital ET SM [5] provides a solution for NR 200MHz transmission, but the generated stair-case voltage is more like a fast average power tracking (APT) SM rather than an ET SM, resulting in limited power efficiency. In addition, the switched-capacitor voltage divider has more than 11 off-chip capacitors and 20 power transistors.