降壓升壓轉換器有助于延長電池壽命的運動檢測

　　許多安全和運動檢測系統依賴于易于安裝的小型、半自治節點。這意味著使用電池為基礎的電源和低功耗操作，以盡量減少電池的數量在產品的使用壽命的變化。

　　在其壽命期間，電池的輸出電壓下降，當電荷接近完全耗盡時最大下降。一個轉換器的類型，可以適應這種變化，在電壓但仍能提供較高的電壓傳感器和射頻發射器的Buck-Boost變換器–操作電路的降壓部分當電池是新鮮的，以增加運行時的電壓低于閾值的電子電路，它的權力。許多供應商已經開發了集成的降壓-升壓轉換器，用于電池系統的優化，本文討論了其中的一些，包括AMS、模擬設備、線性技術、半導體和德克薩斯儀器的設備。

　　運動檢測已經成為現代安全系統的一個組成部分，在家庭或辦公室應該是空的時候，監視入侵者的跡象。隨著時間的推移，我們將看到新的應用程序，將運動檢測擴展到日常生活中，使我們能夠控制照明和媒體設備，通過使用手勢。在家中傳播的設備將監視這些關鍵的手勢，使用先進的信號和圖像處理技術來區分對系統重要的自然動作和手勢。

　　An important link between these systems is the need for distributed， low-energy sensors that can run from batteries to avoid the need to rewire the home to install new systems. They communicate with each other and central processing nodes using low-power radio protocols and use various forms of sensing technology， such as ultrasonic or low-resolution video， to analyze the motion of people.

　　Some types of sensor require high voltages to operate that cannot be generated from the battery cells themselves， or there may be a requirement for a backlight LED or a built-in status display， which needs a high-voltage power source to operate. One option for a step-up or boost regulator is the ON Semiconductor NCP1403. The device is designed to boost a single lithium-ion cell or two AA or AAA cells up to voltages as high as 15 V.

　　In systems that use low-voltage sensors， it is still desirable to have the step-up function available. Simple low-power operation is not enough to eke out the life of a battery. The discharge profile of a typical cell means that it will only deliver its peak voltage at or near the full charge. As the battery discharges， its output voltage will fall， potentially below the supply voltage for which the system has been designed. There is often a very large drop close to full depletion. However， the battery still has energy it can deliver if the surrounding circuitry can make use of it. In reality， the battery rarely empties before it needs changing – it simply cannot deliver usable energy. For example， a 1.5 V AA alkaline cell will generally be considered ‘empty’ when its output voltage falls below 0.9 V.