LED照(zhao)明(ming)驱动ic-LED照(zhao)明(ming)驱动电路与(yu)典型芯片常识
信息(xi)来源:本站(zhan) 日期:2018-01-03
LED驱动(dong)芯(xin)(xin)片(pian),实践(jian)上是个PWM控(kong)制芯(xin)(xin)片(pian),在组(zu)成电(dian)(dian)(dian)路正(zheng)常工作后,经过后面电(dian)(dian)(dian)流(liu)检测电(dian)(dian)(dian)阻上检测LED的(de)电(dian)(dian)(dian)流(liu)而(er)得到的(de)电(dian)(dian)(dian)压反应到芯(xin)(xin)片(pian),控(kong)制内部(bu)的(de)PWM占空(kong)比,以顺应LED本身特(te)性变化而(er)惹(re)起的(de)电(dian)(dian)(dian)流(liu)、电(dian)(dian)(dian)压动(dong)摇,使LED得到的(de)电(dian)(dian)(dian)流(liu)坚持恒定。
依据供(gong)电电压的不同(tong)可将驱(qu)动(dong)电路分为两(liang)类: 直(zhi)流供(gong)电的低电压(0.8—1.65V)电池(如钮扣电池),驱(qu)动(dong)电路宜采用DC/DC 升压式(shi)转换器。其他大于(yu)5V 的直(zhi)流电源(yuan), 驱(qu)动(dong)电路应采用DC/DC 降压式(shi)转换器;直(zhi)接由交流市电供(gong)电的电源(yuan)普(pu)通(tong)需经过AC/DC/DC 变换才可用。
LED驱(qu)动(dong)器是指驱(qu)动(dong)LED发(fa)光(guang)或LED模块组(zu)件正常(chang)(chang)工作(zuo)的(de)电源调整电子(zi)元器件。由于LEDPN结(jie)的(de)导通(tong)特性决议(yi),它(ta)能(neng)顺应的(de)电源的(de)电压和电流变动(dong)范围非常(chang)(chang)狭窄,稍许偏(pian)离就可(ke)能(neng)无法点亮(liang)LED或者发(fa)光(guang)效(xiao)率严重降(jiang)低,或者缩短运用寿命以至(zhi)烧毁芯片。现行的(de)工频电源和常(chang)(chang)见的(de)电池电源均不合适直接供应LED,LED驱(qu)动(dong)器就是这种能(neng)够(gou)差遣LED在(zai)最佳电压或电流状(zhuang)态下(xia)工作(zuo)的(de)电子(zi)组(zu)件。
1、由(you)于LED是特(te)性敏(min)感的半导体器(qi)件(jian),又具有(you)负温度特(te)性,LED驱动电源(也叫驱动器(qi))就是在应用过(guo)程中对其停止稳定工作(zuo)状(zhuang)态的维护。
2、LED器件对驱(qu)动电(dian)(dian)(dian)源(yuan)(yuan)的请求近乎(hu)于苛刻,LED不(bu)像普通的白炽灯(deng)(deng)泡(pao),能够直接(jie)衔(xian)接(jie)220V的交流市(shi)电(dian)(dian)(dian)。LED是低电(dian)(dian)(dian)压驱(qu)动,必(bi)需要设(she)计复(fu)杂的变换(huan)电(dian)(dian)(dian)路,不(bu)同(tong)(tong)用处的LED灯(deng)(deng),要装备(bei)不(bu)同(tong)(tong)的电(dian)(dian)(dian)源(yuan)(yuan)适配器。设(she)计一款(kuan)好(hao)的电(dian)(dian)(dian)源(yuan)(yuan)必(bi)需要综合思索效率转换(huan)、有效功率、恒(heng)流精度(du)、电(dian)(dian)(dian)源(yuan)(yuan)寿命、电(dian)(dian)(dian)磁(ci)兼容这些因(yin)数,由于电(dian)(dian)(dian)源(yuan)(yuan)在整个灯(deng)(deng)具(ju)中的作用就好(hao)比像人的心(xin)脏一样(yang)重要。
LED 照明电路需求(qiu)调理(li)亮度时(shi), 其控(kong)制(zhi)方(fang)式主要(yao)有线性调理(li)LED 的电流(模仿(fang)调光)和(he)应(ying)用PWM 设置占空比和(he)工作周期(数字调光)两种(zhong)。面对(dui)国内外各电子公司(si)上百(bai)种(zhong)的LED 驱动芯片,倡议(yi):一是尽量选用好品牌的产品,二是依据需求(qiu)综合思索质量与本钱。
主要技术照明(ming)电(dian)路按驱(qu)动(dong)方(fang)式也分为两(liang)类(lei)。恒(heng)流(liu)驱(qu)动(dong)的(de)输(shu)出电(dian)流(liu)不变(bian)(bian),输(shu)出电(dian)压随负(fu)载阻值不同变(bian)(bian)化;恒(heng)压驱(qu)动(dong)的(de)输(shu)出电(dian)压不变(bian)(bian),输(shu)出电(dian)流(liu)随着负(fu)载阻值增减变(bian)(bian)化。恒(heng)流(liu)驱(qu)动(dong)是比拟理想的(de)方(fang)式,实践(jian)运用的(de)驱(qu)动(dong)电(dian)路普通均具有(you)恒(heng)压、恒(heng)流(liu)功用。
LED 照(zhao)明驱(qu)动(dong)(dong)电(dian)(dian)路按构造方式(shi)分为器(qi)件(jian)(jian)降(jiang)压(ya)和PWM 开(kai)关电(dian)(dian)源(yuan)(yuan)两种。其中器(qi)件(jian)(jian)降(jiang)压(ya)又(you)有(you)阻容降(jiang)压(ya)、电(dian)(dian)阻降(jiang)压(ya)、变压(ya)器(qi)降(jiang)压(ya)等方式(shi)。PWM 开(kai)关电(dian)(dian)源(yuan)(yuan)是指调理主(zhu)电(dian)(dian)路开(kai)关器(qi)件(jian)(jian)导通脉冲(chong)的宽度来(lai)坚持输(shu)出电(dian)(dian)压(ya)或电(dian)(dian)流(liu)稳(wen)定的驱(qu)动(dong)(dong)方式(shi)。改(gai)动(dong)(dong)占空(kong)比即可改(gai)动(dong)(dong)LED 的均(jun)匀(yun)驱(qu)动(dong)(dong)电(dian)(dian)流(liu),从而改(gai)动(dong)(dong)LED 的发光强(qiang)度。
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