低工作電流類比積體電路

Abstract

隨著可攜式電子產品的發展與盛行，低功率與高效率成為可攜式電子產品的首要考量，因此這些利用電池提供電源的電子電路必須工作在低電壓與低電流以降能量的消耗，使得電池可以長時間的工作。此外，在製程技術不斷地演進的同時，由於可靠度的考量，其工作電壓也必須隨著製程的進步而降低。為了節省功率的消耗，穩壓器常被用來降低工作電壓：將較高的輸入電壓轉換成較低的電壓提供給其他電路使用。而低壓降線性穩壓器（LDO）在可攜式產品盛行的今日更顯得重要，它的優點在於低成本、容易構裝，以及由於輸入電壓與輸入電壓的差值可以很小，因此它可達到低功率的目的。在過去的低壓降穩壓器中，常使用雙載子電晶體來提供所需要的電流，它的優點除了雙載子電晶體可提供大電流的優異能力外，它的高頻寬也使得負載變化時使得穩壓器能夠快速的反應維持輸出電壓。然而，使用雙載子電晶體輸出電流會造成壓降（dropout）的增加或是工作電流會隨輸出電流而增加，此外它也無法和標準製程整合。此外，有些穩壓器必須要使用特定的輸出電容才能維持其穩定性，使用不同種類的電容有可能會造成穩壓器的不穩定。 在這本論文中設計了數種不同規格與用途的低壓降線性穩壓器：（1）高效率低壓降線性穩壓器，這種穩壓器動態地調整其頻寬使得其動態響應與效率能夠同時兼顧；（2）低工作電流低壓降線性穩壓器，只消耗低電流以延長電池壽命；（3）高電源變動拒斥比低壓降線性穩壓器，改善高頻時的電源變動拒斥比並減少維持穩定性所需要的面積。這些低壓降線性穩壓器皆使用標準製程，可與其他電路整合，此外，它的穩定性不因所使用的輸出電容種類不同而受影響。 本論文的另一個主題是盛行的可充電鋰電池所必須的電池保護電路。由於鋰電池在過高電壓時會有燃燒爆炸的危險，因此在每個鋰電池組中都會有一個保護電路來維護電池以及使用者的安全。在本論文中提出了一些低工作電流的設計技巧，並實現了一個非常低工作電流的電池保護電路以其能夠達成保護的作用且不會減少電池的工作時間。

The fast growing demand of portable and battery-operated electronic systems has driven the efforts to reduce power consumption or to improve the efficiency of these electronic equipments. Regulators are essential for most electrically powered systems which include the prevalent portable equipments. Regulators are required to reduce the voltage variations of the battery. Besides, regulators are often utilized to provide a lower voltage from a higher input voltage for power reduction. Current trends in portable or battery-powered electronics demand ultra-low-power consumption or high operating efficiency to prolong the service time of these battery-operated equipments. As a result, low drop-out linear voltage regulators are always in high demand. Some conventional LDO regulators, however, are implemented in non-CMOS processes and require large quiescent current for the regulator itself. The efficiency is poor at a low load current. Besides, some regulators need external compensation and define a limited range of output capacitor for its stability. This external compensation is not convenient for the consumer because an unstable condition occurs when an output capacitor is not properly chosen. This research develops techniques that enable practical circuit realizations of the CMOS low drop-out regulators which are highly efficient and stable with any kind of output capacitors. A series of CMOS low drop-out regulators are developed in this research and they feature high current efficiency, high input voltage ripple rejection, and low quiescent current, respectively. These low drop-out regulators find their uses in cellular phones, pagers, camera recorders, laptops… etc. Keeping pace with the portable electronics, rechargeable batteries are also developed rapidly. One of the popular rechargeable batteries is the Li-ion battery. A Li-ion battery protection IC is also introduced in this research due to the growing family of applications of Li-ion battery. Li-ion battery is popular due to its high energy density, high cell voltage … etc. However, it may be explosive without careful handling. A protection circuit is usually integrated inside the battery pack to prevent danger of explosion. In this research, a CMOS micro-power battery protection integrated circuit is realized and the main features are accuracy and low power consumption. This protection integrated circuit can protect the Li-ion battery from explosion and also prolong the battery operating time.