應用於音訊放大器之高效率可調頻之單電感雙極性直流直流電源轉換器

Abstract

功率放大器一直被廣泛應用在各種電子產品中，其中音頻放大器用於實現對音頻信號的驅動功能。傳統的音頻放大器其電源電壓採用5V (VDD)和0V (VSS),輸出的共模準位在2.5V,因此需要經由一個很大的電容（~22uf）才能消除雜訊幹擾並驅動音響。大電容帶來面積、成本的增大。本論文提出的單一電感雙極輸出可調頻之電源管理系統可以有效的解決這個問題，因為採用多路複用技術同時產生正負電壓供給音頻放大器，使得音頻放大器的輸出共模準位為0V，因此可以去掉大電容並極大地節省面積並減少成本。且此電源管理系統具有根據抽載狀況調整開關頻率的功能，可有效的提升音頻放大器在輕載的效率。此論文之電源管理架構採用0.15微米製程將電源電池電壓轉換成一組大小相等的正負電壓。此外，此論文之供電系統因減少不必要的電流損耗可以達到最高92%的電壓轉換比例及89.4%的能源轉換效率。

Power amplifier has been widely used in a variety of electronic products, including audio amplifier in the circuit to achieve the audio signal driver. The traditional audio amplifier has a supply voltage of 5V (VDD) 0V (VSS), and the output common mode level is at 2.5V, so it is necessary to use a large capacitor (~22uf) to eliminate noise interference and drive the sound. The Large capacitor makes area and cost increase. This paper presents a single inductor bipolar output(SIBO) power management system can effectively solve this problem, because using of multiplexing technology could produce positive and negative voltage supply audio amplifier and make the audio amplifier common mode output voltage at 0V, so it can remove the large capacitor to save area and decrease cost. This power management system could adjust the frequency according to different load. That can effectively enhance the efficiency of the audio amplifier when it works in light load. The power management architecture of this paper uses a 0.15um process to convert the battery supply voltage into a set of equal and bipolar voltages. In addition, the power supply system of this paper achieves a maximum voltage conversion ratio of 92% and an energy conversion efficiency of 89.4% due to reduced unnecessary losses.