具有自動基體電壓切換低輸入電壓單電感雙輸出直流-直流電源轉換器

Abstract

應用於手持式裝置電池電源管理的領域中，如個人數位助理( personal digital assistants, PDAs) 、手機、數位相機…等，延長電池的使用時間和增加電源效率，是設計中很重要的兩項因素。除此之外，體積小也是現今市場上重要的趨勢。因此要如何設計出體積小、效率高且具有低輸入電壓的電源轉換器就成為設計中的一大挑戰。 為了能延長電池的使用時間，我們提出一個具有自動基體電壓切換低電壓輸入雙輸出電源轉換器。電源轉換器可以在低電壓的狀態下透過啟動控制器，在開迴路產生一個高於輸入電壓1V的輸出電壓來提供晶片內部使用，使得系統可以在閉迴路的情況下正常的操作，另外這樣的架構可以使兩個輸出間互相干擾的狀況(cross regulation)變得最低，並利用自動基體電壓切換電路，減少漏電和防止latch-up 發生，進一步達到增加電源效率的目的。 本論文實現了一個具有自動基體電壓切換低電壓輸入單電感雙輸出直流-直流電源轉換器。輸入電壓為1V，輸出電壓為1.8V和0.6V，最大電源負載為40mA。利用TSMC 0.25um BCD 2.5V/5V 1P5M製程進行模擬及製作驗證。

For battery powered portable applications, such as personal digital assistants (PDAs), mobile phones, digital cameras, etc, extending the battery life time and increasing the power conversion efficiency become the two important design issues. Besides, the compact size is also a design requirement in today’s market. Thus, a single inductor is needed to provide multiple outputs for reducing the footprint area of the power module. How to design a compact size, high conversion efficiency and low input supply voltage become a challenge for the power management in portable devices. In order to extend the life time of the battery, a low-voltage dual-output power converter with automatic substrate switching mechanism is proposed in this thesis. Owing to the low supply voltage, the power converter has a startup procedure to make sure the correctness of the whole chip. Besides, owing to the open-loop control of the startup, the converter can have a higher voltage than 1V to the whole chip. Therefore, in the closed-loop control, the possibility that the power consumption of the buck output is larger than that of the boost output can be effectively reduced. In other words, the cross regulation can be minimized. Besides, the implementation of the automatic body switch can avoid the leakage and the latch-up problem. Namely, the performance of the SIDO converter can be improved. This thesis proposes an automatic substrate switching circuit in a single-inductor and dual-output (SIDO) DC-DC converter. The supply voltage can be as low as 1V and the dual outputs are 0.6V and 1.8V, which are one buck output and one boost output. The maximum load is approximated to 40mA for each output. The chip is simulated and fabricated in TSMC 0.25um 2.5V/5V 1P5M BCD process of CMOS technology.