Power Conversion for 4G/5G Envelope Tracking

Wireless communication uses radio frequency power amplifiers (RFPAs) to amplify the signal before transmitting. Traditional RFPAs in communication base stations use fixed voltage DC power supplies. For the communication signal with high peak to average power ratio (PAPR), linear RFPAs will be inefficient and excess power will dissipate as heat. Therefore, a larger cooling system will be required and make communication base station system bulky. To improve the efficiency and miniaturize the system, envelope tracking power supplies are being used. Envelope tracking (ET) power supply utilize envelope extractor to obtain the envelope of the transmitted signal waveform. The output voltage is modulated to track the envelope of communication signal and supply the RFPAs. Communication signal will be distorted if the converter switching frequency is less than signal bandwidth. Thus, ET power supplies are required to switch at several tens of MHz for 4G/5G signals.

4-phase Buck Converter for 4G Envelope Tracking