開關(guan)電源(yuan)模塊阻抗(kang)(kang)是指內部電(dian)(dian)(dian)(dian)(dian)阻、電(dian)(dian)(dian)(dian)(dian)容(rong)和電(dian)(dian)(dian)(dian)(dian)感(gan)(gan)(gan)組成的(de)電(dian)(dian)(dian)(dian)(dian)路對(dui)(dui)交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)起到阻礙作用(yong)。電(dian)(dian)(dian)(dian)(dian)阻的(de)阻抗(kang)(kang)就(jiu)是其本身，電(dian)(dian)(dian)(dian)(dian)容(rong)電(dian)(dian)(dian)(dian)(dian)感(gan)(gan)(gan)兩(liang)者對(dui)(dui)交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)的(de)阻礙叫(jiao)電(dian)(dian)(dian)(dian)(dian)抗(kang)(kang)。電(dian)(dian)(dian)(dian)(dian)容(rong)在電(dian)(dian)(dian)(dian)(dian)路中對(dui)(dui)交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)阻礙叫(jiao)容(rong)抗(kang)(kang)，交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)頻率(lv)越大，容(rong)抗(kang)(kang)越小，有隔(ge)直通交(jiao)(jiao)(jiao)的(de)作用(yong)。電(dian)(dian)(dian)(dian)(dian)感(gan)(gan)(gan)在電(dian)(dian)(dian)(dian)(dian)路中對(dui)(dui)交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)阻礙叫(jiao)感(gan)(gan)(gan)抗(kang)(kang)，交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)頻率(lv)越大，感(gan)(gan)(gan)抗(kang)(kang)就(jiu)越大，有對(dui)(dui)交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)通直隔(ge)交(jiao)(jiao)(jiao)的(de)作用(yong)，可進(jin)行濾波。
　　電(dian)源模塊(kuai)(kuai)內阻較大會不利(li)于負載穩(wen)壓(ya)(ya)電(dian)路工作，嚴重的(de)(de)負載電(dian)流任何變(bian)化都會導致模塊(kuai)(kuai)輸出(chu)的(de)(de)起(qi)伏，起(qi)伏對測(ce)試的(de)(de)影(ying)響和(he)脈沖與噪聲對測(ce)試結(jie)果(guo)的(de)(de)影(ying)響一樣。當線電(dian)壓(ya)(ya)或負載電(dian)流變(bian)化時，直(zhi)流電(dian)源模塊(kuai)(kuai)的(de)(de)輸出(chu)電(dian)壓(ya)(ya)會有所(suo)起(qi)伏。穩(wen)壓(ya)(ya)程(cheng)度由穩(wen)壓(ya)(ya)電(dian)路的(de)(de)參數，濾波電(dian)容(rong)容(rong)量和(he)能量釋放的(de)(de)速率所(suo)決定，穩(wen)定大小(xiao)是空載或滿載時輸出(chu)電(dian)壓(ya)(ya)的(de)(de)百分比或變(bian)化值。
　　瞬態響應或恢復(fu)(fu)(fu)時(shi)間(jian)一般在負(fu)載變(bian)化(hua)10%時(shi)，常用(yong)(yong)輸(shu)出(chu)偏離(li)峰值(zhi)電壓(ya)的(de)毫伏(fu)(fu)數標定輸(shu)出(chu)偏離(li)量(liang)，用(yong)(yong)輸(shu)出(chu)恢復(fu)(fu)(fu)到(dao)正常值(zhi)所用(yong)(yong)毫伏(fu)(fu)數標出(chu)恢復(fu)(fu)(fu)時(shi)間(jian)。電源模塊(kuai)瞬態響應和恢復(fu)(fu)(fu)時(shi)間(jian)的(de)大小(xiao)表明(ming)輸(shu)出(chu)負(fu)載在突然(ran)變(bian)化(hua)時(shi)，穩壓(ya)電路(lu)恢復(fu)(fu)(fu)正常電壓(ya)能力(li)的(de)大小(xiao)，一般是用(yong)(yong)當負(fu)載突然(ran)發生變(bian)化(hua)時(shi)輸(shu)出(chu)的(de)偏離(li)值(zhi)或是輸(shu)出(chu)恢復(fu)(fu)(fu)到(dao)原來(lai)值(zhi)所用(yong)(yong)的(de)時(shi)間(jian)來(lai)標定。

　　阻(zu)(zu)(zu)抗匹配可以(yi)調整負載(zai)功率和抑制(zhi)信號(hao)反射，信號(hao)源或(huo)傳輸線跟負載(zai)間(jian)達到合適搭配叫做阻(zu)(zu)(zu)抗匹配。對(dui)于一個純(chun)電(dian)阻(zu)(zu)(zu)電(dian)路或(huo)低頻電(dian)路，電(dian)容電(dian)感的電(dian)抗值基本(ben)可以(yi)忽略，電(dian)路阻(zu)(zu)(zu)抗主要來源電(dian)阻(zu)(zu)(zu)。

　　在高(gao)(gao)頻(pin)(pin)領域中，當(dang)信號波(bo)長(chang)和傳輸線(xian)長(chang)處于(yu)相(xiang)同量(liang)級時，反(fan)射信號易與原信號混疊，而阻(zu)抗匹配可以有效減少消除(chu)高(gao)(gao)頻(pin)(pin)信號反(fan)射。PCB走(zou)線(xian)阻(zu)抗主要(yao)(yao)來自寄生電(dian)容、電(dian)感、電(dian)阻(zu)，因素(su)有材料介電(dian)常(chang)數(shu)、線(xian)寬、線(xian)厚和焊盤的(de)厚度等。高(gao)(gao)頻(pin)(pin)領域中信號頻(pin)(pin)率對(dui)PCB走(zou)線(xian)的(de)阻(zu)抗值影響(xiang)很(hen)大(da)，當(dang)數(shu)字信號邊(bian)沿(yan)時間小于(yu)1ns或模擬信號頻(pin)(pin)率超(chao)過300M就要(yao)(yao)考慮阻(zu)抗問題。
　　目前阻抗(kang)匹配的方法主要(yao)有改變阻抗(kang)力或調(diao)整(zheng)傳(chuan)輸(shu)線(xian)兩種。改變阻抗(kang)力是指通過電容(rong)、電感與(yu)負(fu)(fu)(fu)載(zai)的串聯(lian)并(bing)聯(lian)調(diao)整(zheng)負(fu)(fu)(fu)載(zai)阻抗(kang)值(zhi)，達(da)到源(yuan)和負(fu)(fu)(fu)載(zai)阻抗(kang)匹配。調(diao)整(zheng)傳(chuan)輸(shu)線(xian)是加長源(yuan)和負(fu)(fu)(fu)載(zai)間(jian)的距離，配合電容(rong)電感把阻抗(kang)力調(diao)為(wei)零(ling)。
　　開關電源目(mu)標阻(zu)(zu)抗(kang)是電源系統(tong)的瞬態(tai)阻(zu)(zu)抗(kang)，和一定寬度的頻段有關，在相同條件下，電源系統(tong)的頻率越大，其阻(zu)(zu)抗(kang)越大。