開關電(dian)源模塊阻(zu)抗(kang)(kang)是指(zhi)內部電(dian)(dian)阻(zu)、電(dian)(dian)容(rong)(rong)(rong)(rong)和電(dian)(dian)感組成的電(dian)(dian)路(lu)(lu)對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)起到(dao)阻(zu)礙(ai)作用。電(dian)(dian)阻(zu)的阻(zu)抗(kang)(kang)就是其本(ben)身，電(dian)(dian)容(rong)(rong)(rong)(rong)電(dian)(dian)感兩(liang)者對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)的阻(zu)礙(ai)叫電(dian)(dian)抗(kang)(kang)。電(dian)(dian)容(rong)(rong)(rong)(rong)在電(dian)(dian)路(lu)(lu)中(zhong)對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)阻(zu)礙(ai)叫容(rong)(rong)(rong)(rong)抗(kang)(kang)，交(jiao)(jiao)(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)頻(pin)率越大(da)，容(rong)(rong)(rong)(rong)抗(kang)(kang)越小，有隔(ge)(ge)直通交(jiao)(jiao)(jiao)(jiao)的作用。電(dian)(dian)感在電(dian)(dian)路(lu)(lu)中(zhong)對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)阻(zu)礙(ai)叫感抗(kang)(kang)，交(jiao)(jiao)(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)頻(pin)率越大(da)，感抗(kang)(kang)就越大(da)，有對(dui)交(jiao)(jiao)(jiao)(jiao)流(liu)(liu)(liu)電(dian)(dian)通直隔(ge)(ge)交(jiao)(jiao)(jiao)(jiao)的作用，可(ke)進行(xing)濾波。
　　電(dian)(dian)源模塊(kuai)內阻較大(da)(da)會不利于(yu)負載(zai)穩(wen)壓電(dian)(dian)路(lu)工作，嚴重(zhong)的(de)(de)負載(zai)電(dian)(dian)流任何變(bian)化都(dou)會導致模塊(kuai)輸出的(de)(de)起伏(fu)(fu)(fu)，起伏(fu)(fu)(fu)對測(ce)(ce)試的(de)(de)影響(xiang)和脈(mo)沖與噪聲對測(ce)(ce)試結(jie)果的(de)(de)影響(xiang)一(yi)樣(yang)。當線電(dian)(dian)壓或負載(zai)電(dian)(dian)流變(bian)化時(shi)，直流電(dian)(dian)源模塊(kuai)的(de)(de)輸出電(dian)(dian)壓會有(you)所(suo)起伏(fu)(fu)(fu)。穩(wen)壓程度由(you)穩(wen)壓電(dian)(dian)路(lu)的(de)(de)參數，濾波電(dian)(dian)容(rong)容(rong)量和能量釋放的(de)(de)速率所(suo)決定(ding)，穩(wen)定(ding)大(da)(da)小是空載(zai)或滿載(zai)時(shi)輸出電(dian)(dian)壓的(de)(de)百分比或變(bian)化值。
　　瞬態(tai)響應或恢復時(shi)(shi)間(jian)一般(ban)在負載(zai)變化10%時(shi)(shi)，常(chang)用(yong)輸(shu)出偏離(li)峰值(zhi)電(dian)壓的(de)(de)毫(hao)伏數(shu)標定(ding)(ding)輸(shu)出偏離(li)量，用(yong)輸(shu)出恢復到(dao)正(zheng)(zheng)常(chang)值(zhi)所用(yong)毫(hao)伏數(shu)標出恢復時(shi)(shi)間(jian)。電(dian)源模塊瞬態(tai)響應和恢復時(shi)(shi)間(jian)的(de)(de)大小(xiao)表明輸(shu)出負載(zai)在突然變化時(shi)(shi)，穩壓電(dian)路(lu)恢復正(zheng)(zheng)常(chang)電(dian)壓能力的(de)(de)大小(xiao)，一般(ban)是用(yong)當負載(zai)突然發生變化時(shi)(shi)輸(shu)出的(de)(de)偏離(li)值(zhi)或是輸(shu)出恢復到(dao)原來值(zhi)所用(yong)的(de)(de)時(shi)(shi)間(jian)來標定(ding)(ding)。

　　阻抗匹配可(ke)以(yi)調整負載功率和(he)抑制信號(hao)反射，信號(hao)源或傳輸線跟負載間達到合適(shi)搭配叫做阻抗匹配。對于一(yi)個純電(dian)阻電(dian)路(lu)或低頻電(dian)路(lu)，電(dian)容電(dian)感的電(dian)抗值基本可(ke)以(yi)忽(hu)略，電(dian)路(lu)阻抗主要來(lai)源電(dian)阻。

　　在(zai)高頻領域(yu)中，當信(xin)(xin)號波長(chang)和(he)傳輸(shu)線長(chang)處于相(xiang)同量級時，反(fan)射信(xin)(xin)號易與原(yuan)信(xin)(xin)號混疊，而阻(zu)抗匹配可以有效減(jian)少消除高頻信(xin)(xin)號反(fan)射。PCB走線阻(zu)抗主要(yao)來自寄生電(dian)容、電(dian)感、電(dian)阻(zu)，因素有材料介電(dian)常數、線寬(kuan)、線厚和(he)焊盤(pan)的厚度等。高頻領域(yu)中信(xin)(xin)號頻率對PCB走線的阻(zu)抗值影響很大，當數字信(xin)(xin)號邊沿時間(jian)小于1ns或模擬信(xin)(xin)號頻率超過300M就要(yao)考慮阻(zu)抗問題。
　　目前阻抗(kang)匹(pi)配(pei)的(de)方法主要有(you)改變阻抗(kang)力(li)或(huo)調(diao)(diao)整傳(chuan)輸(shu)(shu)線兩種。改變阻抗(kang)力(li)是指通過電(dian)(dian)(dian)容、電(dian)(dian)(dian)感(gan)與負載的(de)串(chuan)聯(lian)并(bing)聯(lian)調(diao)(diao)整負載阻抗(kang)值，達到(dao)源和負載阻抗(kang)匹(pi)配(pei)。調(diao)(diao)整傳(chuan)輸(shu)(shu)線是加長源和負載間的(de)距離，配(pei)合電(dian)(dian)(dian)容電(dian)(dian)(dian)感(gan)把阻抗(kang)力(li)調(diao)(diao)為(wei)零。
　　開(kai)關電源目標阻抗(kang)是電源系統(tong)的(de)瞬態阻抗(kang)，和一(yi)定寬度的(de)頻(pin)段有關，在相同條件下，電源系統(tong)的(de)頻(pin)率(lv)越大，其阻抗(kang)越大。