功率調(diào)節(jié)約束設(shè)計

　　便攜式和嵌入式產(chǎn)品空間已經(jīng)從簡單的日子開始，整個系統(tǒng)的基礎(chǔ)設(shè)施是基于12 V模擬傳感器和5 V邏輯電平。隨著越來越多的嵌入式顯示器，新的傳感器，內(nèi)存，I OS和先進的低功耗控制器的使用，大多數(shù)嵌入式系統(tǒng)現(xiàn)在需要大量的電力領(lǐng)域，其中可能包括0.8至1.8伏，2.3伏，2.7伏，3.3伏，5伏和12 V電源的混合物。

　　外部電源變壓器只提供一個電壓電平，所以其余必須在PCB上生成。這通常是使用多個不同的個人權(quán)力的監(jiān)管機構(gòu)或一個更復(fù)雜的電源管理IC（PMIC）。這些集成電路的選擇是基于電壓輸出、當(dāng)前支持的水平和設(shè)計的熱操作條件。

　　Why multiple power supplies？

　　Today‘s embedded systems are often designed using multiple technologies. Most designs have a combination of components that include MOS， bipolar， MEMS， TFT-LCD， and LED technologies. As process and manufacturing scaling has progressed， the nominal operative voltage for ICs has dropped. The amount of current per transistor has also dropped; however， since there are more transistors per chip in most designs， the net current draw has not necessarily gone down. The use of mixed technology in a design is driving the need for multiple power regulators.