LED照明电路图,原理图分享-KIA MOS管

LED照明电路原理

LED照(zhao)明电路是(shi)一种将电能转换为光(guang)(guang)能的(de)电路，使用LED（发光(guang)(guang)二极管）作(zuo)为光(guang)(guang)源。LED由一个(ge)PN结(jie)组成，当电流通(tong)过(guo)时，电子(zi)和(he)空穴在PN结(jie)区域复合，释放出能量并发出光(guang)(guang)子(zi)。这(zhei)个(ge)过(guo)程(cheng)是(shi)高度量子(zi)化的(de)，因此LED能够发出特定波长和(he)颜(yan)色(se)的(de)光(guang)(guang)。

LED照明电(dian)(dian)(dian)(dian)路通(tong)(tong)常(chang)包(bao)括电(dian)(dian)(dian)(dian)源(yuan)(yuan)部分、驱动(dong)电(dian)(dian)(dian)(dian)路和控(kong)制(zhi)电(dian)(dian)(dian)(dian)路三个部分。电(dian)(dian)(dian)(dian)源(yuan)(yuan)部分用(yong)于提供稳定的(de)(de)(de)(de)电(dian)(dian)(dian)(dian)源(yuan)(yuan)电(dian)(dian)(dian)(dian)压或(huo)电(dian)(dian)(dian)(dian)流(liu)，一般(ban)可以(yi)使用(yong)开关电(dian)(dian)(dian)(dian)源(yuan)(yuan)或(huo)直流(liu)电(dian)(dian)(dian)(dian)源(yuan)(yuan)来(lai)(lai)(lai)提供。驱动(dong)电(dian)(dian)(dian)(dian)路用(yong)于将电(dian)(dian)(dian)(dian)源(yuan)(yuan)电(dian)(dian)(dian)(dian)压或(huo)电(dian)(dian)(dian)(dian)流(liu)转化为适(shi)合(he)LED正常(chang)工作的(de)(de)(de)(de)电(dian)(dian)(dian)(dian)压或(huo)电(dian)(dian)(dian)(dian)流(liu)，LED一般(ban)需(xu)要驱动(dong)电(dian)(dian)(dian)(dian)流(liu)在20mA左右，因此驱动(dong)电(dian)(dian)(dian)(dian)路可以(yi)通(tong)(tong)过(guo)电(dian)(dian)(dian)(dian)阻、电(dian)(dian)(dian)(dian)流(liu)源(yuan)(yuan)、电(dian)(dian)(dian)(dian)流(liu)控(kong)制(zhi)芯(xin)片(pian)等器件(jian)来(lai)(lai)(lai)实现(xian)。控(kong)制(zhi)电(dian)(dian)(dian)(dian)路用(yong)于调(diao)节LED的(de)(de)(de)(de)亮(liang)度或(huo)色(se)温等参数，可以(yi)通(tong)(tong)过(guo)PWM调(diao)节电(dian)(dian)(dian)(dian)流(liu)或(huo)电(dian)(dian)(dian)(dian)压的(de)(de)(de)(de)大小来(lai)(lai)(lai)控(kong)制(zhi)LED的(de)(de)(de)(de)亮(liang)度，也可以(yi)通(tong)(tong)过(guo)单片(pian)机或(huo)控(kong)制(zhi)芯(xin)片(pian)来(lai)(lai)(lai)实现(xian)更复杂的(de)(de)(de)(de)调(diao)光(guang)效果。

IC555 LED照明电路图

该电路(lu)的工作从IC555开始，它(ta)被连接为一个发出(chu)方(fang)波作为输出的无稳态多谐振荡器。

555IC的(de)输(shu)出(chu)频率(lv)取(qu)决于RC值(zhi)R、RV1和C2，改(gai)变(bian)这(zhei)些(xie)值(zhi)将导(dao)致输(shu)出(chu)频率(lv)发生(sheng)变(bian)化(hua)。这(zhei)可(ke)以(yi)通过(guo)改(gai)变(bian)可(ke)变(bian)电(dian)阻器RV1的(de)电(dian)阻值(zhi)来完成(cheng)。

LED照明电路,原理

555 IC 的(de)输出将(jiang)比供电(dian)电(dian)压(ya)低 1.7v，并且还(hai)提供约 200mA 的(de)电(dian)流。该电(dian)流源不(bu)足(zu)以容纳 40 个 LED，这就是晶体(ti)管开关在该电(dian)路中发挥作(zuo)用的(de)地(di)方(fang)。

NPN 晶(jing)(jing)体管(guan)(guan) 2N3055 用于打开第 I 组蓝(lan)色 LED，而 PNP 晶(jing)(jing)体管(guan)(guan) 2N2905 用于打开第 II 组红色 LED。当基(ji)极施加超(chao)过(guo) 0.7V 的正 V 且电(dian)流进入基(ji)极时，NPN 晶(jing)(jing)体管(guan)(guan)导通。但对于 PNP 晶(jing)(jing)体管(guan)(guan)，只有当基(ji)极连接到(dao)负极或接地并且电(dian)流离开此处时，它才会导通。

当(dang)从 555 IC 获(huo)得(de)高电(dian)(dian)平或(huo)逻辑(ji) 1 信号时，晶体(ti)管(guan) Q1 2N3055 将打开，使蓝色 LED 发光(guang)。 R3 是 Q1 的(de)基极(ji)电(dian)(dian)阻，用于限(xian)(xian)制(zhi)(zhi)电(dian)(dian)流。当(dang)从 555 获(huo)得(de)低电(dian)(dian)平或(huo)逻辑(ji) 0 时，晶体(ti)管(guan) Q2 2N2905 将导通，因(yin)为基极(ji)端子将等于零(ling)电(dian)(dian)位。这使得(de)红色 LED 发光(guang)，并且 R4 起到(dao)限(xian)(xian)制(zhi)(zhi)电(dian)(dian)流的(de)作用。

综(zong)上(shang)所述，555 发出的高信(xin)号将使(shi)蓝色 LED 发光，而低信(xin)号将使(shi)红色 LED 亮起。因(yin)此(ci)，连续方波输(shu)出可(ke)与 LED 产(chan)生交替的照明效果。可(ke)以在晶体管 Q2 的基极串联添(tian)加一个(ge)二极管，以避(bi)免信(xin)号为高电平时发生切换。

LED照明电路图

整流电(dian)路由电(dian)源变压(ya)器(qi)T和整流桥堆UR组成，其(qi)作(zuo)用(yong)是将220V的市电(dian)转化为(wei)18V的直流电(dian)压(ya)。经过C滤波后，这(zhei)个(ge)直流电(dian)压(ya)即可作(zuo)为(wei)照明(ming)电(dian)源使(shi)用(yong)。

0个(ge)LED灯(deng)被(bei)巧(qiao)妙地设计(ji)成(cheng)每5个(ge)串(chuan)联为(wei)一(yi)组(zu)，总共分为(wei)4组(zu)进(jin)行并联，从而构成(cheng)了(le)(le)台灯(deng)的照(zhao)明(ming)阵列。这样的布局不(bu)仅确保(bao)了(le)(le)每组(zu)LED的电(dian)(dian)流(liu)保(bao)持(chi)一(yi)致，降(jiang)低(di)了(le)(le)整体电(dian)(dian)流(liu)，还有(you)效(xiao)地保(bao)证了(le)(le)即使(shi)某一(yi)组(zu)LED损坏，其他(ta)组(zu)仍能(neng)继续提(ti)供(gong)(gong)照(zhao)明(ming)。为(wei)了(le)(le)进(jin)一(yi)步提(ti)升照(zhao)明(ming)品质和(he)效(xiao)果，该台灯(deng)还采用了(le)(le)恒(heng)流(liu)供(gong)(gong)电(dian)(dian)技术(shu)。在图2-35所示的电(dian)(dian)路中，场效(xiao)应(ying)管VT与电(dian)(dian)阻R共同构成(cheng)了(le)(le)一(yi)个(ge)恒(heng)流(liu)源，为(wei)LED照(zhao)明(ming)阵列提(ti)供(gong)(gong)了(le)(le)稳定且高效(xiao)的电(dian)(dian)流(liu)供(gong)(gong)应(ying)。

LED照明电路,原理

结型(xing)场(chang)效应管在(zai)LED台灯电(dian)路中发挥(hui)着重要作(zuo)用，它可以轻松地构成恒(heng)流源，为(wei)LED提供稳(wen)定(ding)(ding)的(de)电(dian)流。其恒(heng)流原(yuan)理在(zai)于，当(dang)场(chang)效应管的(de)漏极(ji)电(dian)流ID意外增加时，源极(ji)电(dian)阻(zu)RS上产生的(de)负(fu)(fu)栅(zha)压也会相应增大，从(cong)而抑制ID的(de)进一步增加；反(fan)之，当(dang)ID减(jian)小(xiao)(xiao)，负(fu)(fu)栅(zha)压也会相应减(jian)小(xiao)(xiao)，促使ID回(hui)升(sheng)。这(zhei)样的(de)设计确(que)保了电(dian)流ID的(de)稳(wen)定(ding)(ding)输出。其中Up代(dai)表场效(xiao)应(ying)管(guan)的夹断电压。

LED照明电路,原理