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微机继电器保护采用印制电路板的抗干扰

来源：detroitsignfactory.com    更(geng)新时间：2020-09-21 

微(wei)机保(bao)护(hu)的电路中,有数字、模拟,高频、低频等各种信号，在(zai)涉(she)及(ji)电路板(ban)中，要求印(yin)刷电路板(ban)（PCB）布线应(ying)尽量减少不同部(bu)分相互间的各种耦(ou)合干(gan)扰。

抗(kang)干(gan)扰的(de)(de)措施有：合理的(de)(de)电(dian)(dian)路(lu)板布线(xian)(xian)(xian)技术（环绕(rao)布线(xian)(xian)(xian)、线(xian)(xian)(xian)经选(xuan)择、分层(ceng)处理）；电(dian)(dian)源(yuan)线(xian)(xian)(xian)、地(di)线(xian)(xian)(xian)的(de)(de)布线(xian)(xian)(xian)尽量加粗和(he)缩短，以(yi)减少(shao)环路(lu)电(dian)(dian)阻，转角圆(yuan)滑，尽量不要出现(xian)90°一(yi)下的(de)(de)折角；低频(pin)电(dian)(dian)路(lu)部分的(de)(de)接(jie)地(di)采用(yong)单(dan)点并联(lian)接(jie)地(di)方式(shi)，或部分串联(lian)后在并联(lian)接(jie)地(di)；高(gao)(gao)频(pin)电(dian)(dian)路(lu)采用(yong)多点就近(jin)接(jie)地(di)；在高(gao)(gao)频(pin)元(yuan)件如晶振电(dian)(dian)路(lu)、A/D转换器等(deng)电(dian)(dian)路(lu)周围(wei)，尽量用(yong)傅铜栅格形式(shi)地(di)钵包围(wei)；信(xin)(xin)(xin)号(hao)线(xian)(xian)(xian)近(jin)可能(neng)远(yuan)离电(dian)(dian)源(yuan)线(xian)(xian)(xian)。模(mo)拟输入线(xian)(xian)(xian)与数字(zi)信(xin)(xin)(xin)号(hao)线(xian)(xian)(xian)不平行并排(pai)；重(zhong)要的(de)(de)信(xin)(xin)(xin)号(hao)线(xian)(xian)(xian)不远(yuan)行饶布；电(dian)(dian)源(yuan)和(he)低频(pin)信(xin)(xin)(xin)号(hao)连接(jie)线(xian)(xian)(xian)采用(yong)小(xiao)节距(ju)的(de)(de)双(shuang)绞线(xian)(xian)(xian)，多根信(xin)(xin)(xin)号(hao)线(xian)(xian)(xian)用(yong)一(yi)扁平排(pai)连接(jie)时，信(xin)(xin)(xin)号(hao)线(xian)(xian)(xian)间插入隔离地(di)线(xian)(xian)(xian)。

尽量减(jian)少电(dian)路(lu)与(yu)电(dian)路(lu)之(zhi)间、电(dian)路(lu)板之(zhi)间的电(dian)磁(ci)干扰(rao)。PCB板电(dian)源(yuan)线(xian)与(yu)地线(xian)尽量靠近以(yi)尽孝包围的面积，减(jian)小外界磁(ci)场切割电(dian)源(yuan)环路(lu)产生的电(dian)磁(ci)干扰(rao)，也减(jian)少环路(lu)对外的电(dian)磁(ci)辐射。

选择(ze)合适量值的退藕电(dian)(dian)容可消除电(dian)(dian)源干扰信(xin)号(hao)，通常选择(ze)0.1ｕF的瓷片电(dian)(dian)容或独石电(dian)(dian)容。

近几(ji)年开发的保护产品(pin)采用其他CPU的正常工(gong)作，从(cong)而提(ti)高了(le)保护的可靠性。

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