2-Tx Digital Envelope-Tracking Supply Modulator Achieving 200MHz Channel Bandwidth and 93.6% Efficiency for 2G/3G/LTE/NR RF Power Amplifiers
Jun‐Suk Bang, Dongsu Kim, Jeongkwang Lee, Sung-Youb Jung, Younghwan Choo, Seung‐Chan Park, Youngho Jung, Jae-Young Ko, Takahiro Nomiyama, Jongbeom Baek, Jaeyeol Han, Sang-Han Lee, Ik-Hwan Kim, Ji-Seon Paek, Jongwoo Lee, Thomas Byunghak Cho
Abstract
Envelope tracking (ET) has become essential technology to save power consumption of RF power amplifiers (PAs) in mobile handsets. 5G NR standard continuously increases their maximum channel bandwidth (CH BW) for intra-band contiguous carrier aggregation (CA) to improve data rate. 3GPP TS 38.101 (Release 16) introduces maximum aggregated BW cases of 200MHz (CA_n77C, CA_n78C, CA_n79C), 300M Hz (CA_n77D, CA_n78D, CA_n79D) and even 320M Hz (CA_n46E) [1]. However, the CH BWs that can be supported by conventional analog ET supply modulators, composed of a switching amplifier and an analog linear amplifier, almost reach their limit due to large PA decoupling capacitor (few hundreds of pF) and high-voltage process (>5V). The supply modulator (SM) in [3] isolates decoupling capacitors of unused PAs by a switch, and the linear amplifier in [5] partially employs low-voltage devices to achieve wider BW, however, still 130MHz is the widest envelope-tracking BW among supply modulators with high output voltage (4 to 5V).