降壓升壓轉(zhuǎn)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(tǒng)依賴于易于安裝的小型、半自治節(jié)點。這意味著使用電池為基礎(chǔ)的電源和低功耗操作，以盡量減少電池的數(shù)量在產(chǎn)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(dāng)電荷接近完全耗盡時最大下降。一個轉(zhuǎn)換器的類型，可以適應(yīng)這種變化，在電壓但仍能提供較高的電壓傳感器和射頻發(fā)射器的Buck-Boost變換器–操作電路的降壓部分當(dāng)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(quán)力。許多供應(yīng)商已經(jīng)開發(fā)了集成的降壓-升壓轉(zhuǎn)換器，用于電池系統(tǒng)的優(yōu)化，本文討論了其中的一些，包括AMS、模擬設(shè)備、線性技術(shù)、半導(dǎo)體和德克薩斯儀器的設(shè)備。

　　運動檢測已經(jīng)成為現(xiàn)代安全系統(tǒng)的一個組成部分，在家庭或辦公室應(yīng)該是空的時候，監(jiān)視入侵者的跡象。隨著時間的推移，我們將看到新的應(yīng)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(shè)備，通過使用手勢。在家中傳播的設(shè)備將監(jiān)視這些關(guān)鍵的手勢，使用先進的信號和圖像處理技術(shù)來區(qū)分對系統(tǒng)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.