具低電壓漣波與高轉換率之電源管理模組應用於光通訊接收系統

Abstract

本論文實現一電源管理控制晶片,整合於光通訊接收系統，傳統上光通訊系統利用雪崩光二極體(APD)與轉導放大器(TIA)作為訊號接收器。在積體整合的趨勢下，需同時將寫雪崩光二極體與轉導放大器整合於同一片晶片上；然由於電壓需求的差異與通訊品質的要求，電源管理IC必須提供同時提供高輸出電壓並抑制輸出漣波的產生。與此同時，電壓變化與溫度變化的影響下，均會對訊號的品質產生影響，提高了積體化的困難度。 本論文中利用電壓回授的控制技術，以動態調整輸出電壓達到溫度補償，如此可以確保訊號的品質不會受到溫度變化的影響。此外，為了減少電源管理模組的體積與外部元件，除了利用單一直流-直流升壓轉換器的架構外，並將輸出電壓提高至80伏特。在此同時，為避免輸出的電壓漣波動對通訊信號產生干擾而影響通訊品質，本論文提出一動態零電流的偵測機制，可以精準預測零電流產生的時間，將多餘的電荷排除，大幅地制輸出電壓漣波的大小，提供一適合的電源管理模組。

Avalanche photodiodes (APDs) accompanied with the Trans-impedance Amplifiers (TIAs) are often utilized as receivers in the communication system. A drawback of APDs is the avalanche gain depends on temperature and varies with the bias voltage, leading to a decrease in the quality of communication. Besides, the bias voltage for a high avalanche gain is up to 80 V, implying a power module is inevitably required and raises the difficulty of integration. Therefore, a power management is proposed to provide an 80V voltage and compensates the temperature dependency for a constant avalanche gain. The low-ripple high conversion-ratio (LRHCR) boost converter eliminates the LC resonance resulted from the non-ideal effect of diodes to suppress the output voltage ripple, implying a high quality of bias voltage is guaranteed. Experimental results show the output voltage ripple is 2.12 mV under the condition of 1 mA load current. A 97% accuracy of avalanche gain is proved to guarantee the high quality of APDs.