開關電源(yuan)模塊(kuai)阻抗是(shi)指(zhi)內部電(dian)(dian)(dian)阻、電(dian)(dian)(dian)容和電(dian)(dian)(dian)感(gan)組成的電(dian)(dian)(dian)路對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)電(dian)(dian)(dian)起到(dao)阻礙作用。電(dian)(dian)(dian)阻的阻抗就(jiu)是(shi)其本身，電(dian)(dian)(dian)容電(dian)(dian)(dian)感(gan)兩者對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)電(dian)(dian)(dian)的阻礙叫(jiao)電(dian)(dian)(dian)抗。電(dian)(dian)(dian)容在電(dian)(dian)(dian)路中對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)電(dian)(dian)(dian)阻礙叫(jiao)容抗，交(jiao)(jiao)(jiao)(jiao)流(liu)電(dian)(dian)(dian)頻(pin)率越(yue)大，容抗越(yue)小(xiao)，有(you)隔直(zhi)通交(jiao)(jiao)(jiao)(jiao)的作用。電(dian)(dian)(dian)感(gan)在電(dian)(dian)(dian)路中對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)電(dian)(dian)(dian)阻礙叫(jiao)感(gan)抗，交(jiao)(jiao)(jiao)(jiao)流(liu)電(dian)(dian)(dian)頻(pin)率越(yue)大，感(gan)抗就(jiu)越(yue)大，有(you)對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)電(dian)(dian)(dian)通直(zhi)隔交(jiao)(jiao)(jiao)(jiao)的作用，可進行濾波。
　　電(dian)(dian)源(yuan)模(mo)塊(kuai)內阻較大會不利于負(fu)載(zai)穩(wen)壓電(dian)(dian)路工作，嚴重(zhong)的(de)負(fu)載(zai)電(dian)(dian)流(liu)任何變(bian)化都會導致模(mo)塊(kuai)輸出的(de)起(qi)伏(fu)，起(qi)伏(fu)對測(ce)試(shi)的(de)影響和脈沖(chong)與(yu)噪聲對測(ce)試(shi)結果的(de)影響一樣。當線電(dian)(dian)壓或(huo)負(fu)載(zai)電(dian)(dian)流(liu)變(bian)化時(shi)，直流(liu)電(dian)(dian)源(yuan)模(mo)塊(kuai)的(de)輸出電(dian)(dian)壓會有所(suo)起(qi)伏(fu)。穩(wen)壓程(cheng)度由穩(wen)壓電(dian)(dian)路的(de)參數，濾波電(dian)(dian)容(rong)容(rong)量(liang)和能(neng)量(liang)釋(shi)放的(de)速率所(suo)決(jue)定，穩(wen)定大小是空(kong)載(zai)或(huo)滿載(zai)時(shi)輸出電(dian)(dian)壓的(de)百分比或(huo)變(bian)化值。
　　瞬態響應(ying)或恢(hui)復(fu)(fu)時間(jian)一(yi)般在(zai)(zai)負載(zai)(zai)變化(hua)10%時，常用(yong)輸(shu)(shu)出(chu)偏離峰值(zhi)(zhi)電(dian)(dian)壓(ya)的(de)毫伏(fu)數標(biao)(biao)定輸(shu)(shu)出(chu)偏離量，用(yong)輸(shu)(shu)出(chu)恢(hui)復(fu)(fu)到正常值(zhi)(zhi)所用(yong)毫伏(fu)數標(biao)(biao)出(chu)恢(hui)復(fu)(fu)時間(jian)。電(dian)(dian)源模塊瞬態響應(ying)和(he)恢(hui)復(fu)(fu)時間(jian)的(de)大(da)小(xiao)表明輸(shu)(shu)出(chu)負載(zai)(zai)在(zai)(zai)突然變化(hua)時，穩壓(ya)電(dian)(dian)路(lu)恢(hui)復(fu)(fu)正常電(dian)(dian)壓(ya)能力的(de)大(da)小(xiao)，一(yi)般是用(yong)當負載(zai)(zai)突然發生(sheng)變化(hua)時輸(shu)(shu)出(chu)的(de)偏離值(zhi)(zhi)或是輸(shu)(shu)出(chu)恢(hui)復(fu)(fu)到原來(lai)值(zhi)(zhi)所用(yong)的(de)時間(jian)來(lai)標(biao)(biao)定。

　　阻(zu)(zu)(zu)抗(kang)匹(pi)(pi)配(pei)可以(yi)調整負載功率和抑制(zhi)信(xin)號(hao)反射，信(xin)號(hao)源或(huo)傳(chuan)輸線跟負載間達到合(he)適搭配(pei)叫做阻(zu)(zu)(zu)抗(kang)匹(pi)(pi)配(pei)。對于一個(ge)純電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)電(dian)(dian)(dian)(dian)路或(huo)低頻電(dian)(dian)(dian)(dian)路，電(dian)(dian)(dian)(dian)容電(dian)(dian)(dian)(dian)感(gan)的電(dian)(dian)(dian)(dian)抗(kang)值基本可以(yi)忽(hu)略(lve)，電(dian)(dian)(dian)(dian)路阻(zu)(zu)(zu)抗(kang)主(zhu)要(yao)來源電(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)。

　　在高(gao)頻(pin)領域中，當信(xin)(xin)號波長和傳輸(shu)線長處于(yu)相同量級時(shi)，反射信(xin)(xin)號易與原(yuan)信(xin)(xin)號混疊，而阻抗(kang)(kang)匹配(pei)可以有效減(jian)少消除高(gao)頻(pin)信(xin)(xin)號反射。PCB走線阻抗(kang)(kang)主(zhu)要來自寄生電(dian)容、電(dian)感、電(dian)阻，因素有材(cai)料介電(dian)常數(shu)、線寬、線厚(hou)和焊盤的厚(hou)度等。高(gao)頻(pin)領域中信(xin)(xin)號頻(pin)率對PCB走線的阻抗(kang)(kang)值影響很大，當數(shu)字信(xin)(xin)號邊沿時(shi)間小于(yu)1ns或(huo)模擬信(xin)(xin)號頻(pin)率超過(guo)300M就要考(kao)慮阻抗(kang)(kang)問(wen)題。
　　目前阻抗匹(pi)配(pei)(pei)的(de)(de)方法主要有改(gai)變阻抗力(li)或調(diao)(diao)整(zheng)傳(chuan)輸(shu)線(xian)兩種。改(gai)變阻抗力(li)是(shi)指通過電(dian)容、電(dian)感與負載的(de)(de)串(chuan)聯并聯調(diao)(diao)整(zheng)負載阻抗值，達到(dao)源(yuan)和(he)負載阻抗匹(pi)配(pei)(pei)。調(diao)(diao)整(zheng)傳(chuan)輸(shu)線(xian)是(shi)加長源(yuan)和(he)負載間的(de)(de)距離，配(pei)(pei)合電(dian)容電(dian)感把阻抗力(li)調(diao)(diao)為(wei)零。
　　開關電源(yuan)(yuan)目標阻(zu)抗(kang)是電源(yuan)(yuan)系統的瞬(shun)態阻(zu)抗(kang)，和一定寬度的頻(pin)(pin)段有關，在相同條件(jian)下(xia)，電源(yuan)(yuan)系統的頻(pin)(pin)率越大，其阻(zu)抗(kang)越大。