開關電源(yuan)通常使用電(dian)(dian)(dian)感(gan)來臨時(shi)儲能。在評(ping)估這些電(dian)(dian)(dian)源時(shi)，測(ce)量(liang)電(dian)(dian)(dian)感(gan)電(dian)(dian)(dian)流(liu)通常有助于了解完整的電(dian)(dian)(dian)壓轉(zhuan)換電(dian)(dian)(dian)路。但(dan)測(ce)量(liang)電(dian)(dian)(dian)感(gan)電(dian)(dian)(dian)流(liu)的最佳方法是什么(me)？

圖1以典型的降壓型轉換器（降壓拓撲）為例(li)，顯示(shi)了針(zhen)對這類測量的建(jian)議設置。接(jie)入一根(gen)輔助小電(dian)(dian)(dian)纜與電(dian)(dian)(dian)感(gan)串(chuan)聯。將(jiang)它用來連接(jie)一個電(dian)(dian)(dian)流探(tan)頭，并通過示(shi)波(bo)器顯示(shi)電(dian)(dian)(dian)感(gan)電(dian)(dian)(dian)流。建(jian)議在電(dian)(dian)(dian)感(gan)具有(you)穩(wen)定電(dian)(dian)(dian)壓的那一側進行測量。

大多數開(kai)關(guan)穩壓器拓撲使用電感的方式是(shi)，一側(ce)電壓在(zai)兩個極限值(zhi)之間切(qie)換(huan)，而(er)另(ling)一側(ce)電壓則保持相對穩定。對于圖1所示的降壓型(xing)轉換(huan)器，開關節點(dian)（即(ji)電感L的左側）上的電(dian)(dian)(dian)(dian)壓(ya)以開關邊沿的速率在(zai)輸入電(dian)(dian)(dian)(dian)壓(ya)和(he)地(di)電(dian)(dian)(dian)(dian)壓(ya)之間切換(huan)。電(dian)(dian)(dian)(dian)感的右側是輸出電(dian)(dian)(dian)(dian)壓(ya)，通常相對穩定(ding)。為了減少由于電(dian)(dian)(dian)(dian)容耦合（電(dian)(dian)(dian)(dian)場耦合）引起的干擾(rao)，電(dian)(dian)(dian)(dian)流測量環路應放置在(zai)電(dian)(dian)(dian)(dian)感安(an)靜的一側，如(ru)圖(tu)1所示。

上圖(tu)顯示了通過與所用示波器兼容(rong)的(de)電流探(tan)頭檢測(ce)(ce)到(dao)的(de)開關(guan)電源的(de)電感(gan)(gan)電流（藍色）的(de)測(ce)(ce)量結(jie)果(guo)。除(chu)了顯示為藍色的(de)測(ce)(ce)量結(jie)果(guo)之外，還添(tian)加了紫色標記，它指示當電感(gan)(gan)開始接近峰值(zhi)電流進入(ru)過度飽和時，流過電感(gan)(gan)的(de)電流狀況。

當(dang)選擇(ze)的電(dian)(dian)感(gan)對(dui)于給定的應用(yong)不(bu)能(neng)提供足夠的額定電(dian)(dian)流時，就會(hui)發生這種情況(kuang)。在(zai)開(kai)關電(dian)(dian)源中(zhong)進(jin)行電(dian)(dian)感(gan)電(dian)(dian)流測量的主要原(yuan)因之一(yi)是(shi)，它可(ke)以幫助識(shi)別是(shi)否(fou)正確選擇(ze)了(le)電(dian)(dian)感(gan)，或者在(zai)工作中(zhong)或故障情況(kuang)下是(shi)否(fou)會(hui)出現電(dian)(dian)感(gan)飽和。