封包追蹤電源供應器之研製

Abstract

本論文之研究目的為封包追蹤電源供應器(Envelope Tracking Power Supply，ETPS)之研製，使用封包追蹤技術產生變動電源，取代傳統定電源供給之線性功率放大器以提升其效率。在封包追蹤功率放大器系統中，ETPS之輸出封包與功率放大器輸出之放大訊號，此兩電壓之不同步使功率放大器無法操作於最高效率。一般解決方式是將傳輸之原始訊號經延遲處理得延遲訊號，再使該兩電壓同步。但此方式使原始訊號需經訊號處理，所得之延遲訊號與原始訊號會產生差異。因此，本論文提出不需處理原始訊號之領前封包訊號法，利用簡易實現之相位領前電路，使ETPS之輸出封包盡量與PA之放大訊號兩電壓同步。本論文中，亦對ETPS造成輸出封包與原始訊號之封包訊號間之相位差進行數學分析與電路模擬，探討造成此相位差的原因。最後以操作於1MHz切換頻率，25W之降壓型ETPS硬體電路實驗結果驗證ETPS及領前封包訊號法之可行性。

In this thesis, an envelope tracking power supply (ETPS) using envelope tracking tecknique is proposed to improve the efficiency of a linear power amplifier by producing a changeable voltage supply instead of the conventional constant voltage supply. In an envelope tracking power amplifier system, the nonsynchronization of the two voltages, envelope output produced by the ETPS and amplified signal produced by the power amplifier, causing the problem of degrading the power amplifier efficiency. Delaying the transmitted original signal for a delay time to synchronize two voltages remains the general solution. However, the delayed signal may not be totally identical to the original signal due to the signal processing. Therefore, a solution which the original signal without being processed named leading envelope signal scheme with a simple implemented phase lead circuit to synchronize two voltages is proposed in this thesis. In addition, mathematical analysis and circuit simulations are carried out to discuss the factors of the phase difference caused by the proposed ETPS between the envelope output and the envelope signal of the original signal. Finally, the hardware implementation of a 25W Buck type ETPS operating at 1MHz switching frequency is proposed to verify the feasibility of the ETPS and leading envelope signal scheme.