电容二极管升压电路及发光二极管升压电路详解

升压电路原理

了解二极管升压(ya)电(dian)(dian)(dian)(dian)路(lu)之前，我们来看看升压(ya)电(dian)(dian)(dian)(dian)路(lu)原(yuan)理(li)。升压(ya)电(dian)(dian)(dian)(dian)路(lu)原(yuan)理(li)如下：举(ju)个(ge)简单的(de)例(li)子：有一个(ge)12V的(de)电(dian)(dian)(dian)(dian)路(lu)，电(dian)(dian)(dian)(dian)路(lu)中有一个(ge)场(chang)效应管需要15V的(de)驱动电(dian)(dian)(dian)(dian)压(ya)，这(zhei)个(ge)电(dian)(dian)(dian)(dian)压(ya)怎(zen)么(me)弄出来？就是用(yong)自举(ju)。通(tong)常(chang)用(yong)一个(ge)电(dian)(dian)(dian)(dian)容和一个(ge)二极管，电(dian)(dian)(dian)(dian)容存(cun)储电(dian)(dian)(dian)(dian)荷，二极管防止电(dian)(dian)(dian)(dian)流倒灌，频(pin)率较高的(de)时候，自举(ju)电(dian)(dian)(dian)(dian)路(lu)的(de)电(dian)(dian)(dian)(dian)压(ya)就是电(dian)(dian)(dian)(dian)路(lu)输入的(de)电(dian)(dian)(dian)(dian)压(ya)加上(shang)电(dian)(dian)(dian)(dian)容上(shang)的(de)电(dian)(dian)(dian)(dian)压(ya)，起到升压(ya)的(de)作(zuo)用(yong)。

自(zi)(zi)举(ju)电(dian)(dian)路只是(shi)在(zai)(zai)实(shi)践中(zhong)定(ding)的(de)名(ming)称，在(zai)(zai)理论(lun)上没有这个概(gai)念(nian)。自(zi)(zi)举(ju)电(dian)(dian)路主(zhu)要是(shi)在(zai)(zai)甲乙类单(dan)电(dian)(dian)源(yuan)(yuan)互(hu)补(bu)对(dui)称电(dian)(dian)路中(zhong)使用(yong)较(jiao)为普(pu)遍。甲乙类单(dan)电(dian)(dian)源(yuan)(yuan)互(hu)补(bu)对(dui)称电(dian)(dian)路在(zai)(zai)理论(lun)上可(ke)以使输出电(dian)(dian)压Vo达(da)到Vcc的(de)一半(ban)，但在(zai)(zai)实(shi)际的(de)测(ce)试中(zhong)，输出电(dian)(dian)压远达(da)不到Vcc的(de)一半(ban)。其(qi)中(zhong)重(zhong)要的(de)原因(yin)就需要一个高(gao)于Vcc的(de)电(dian)(dian)压。所以采用(yong)自(zi)(zi)举(ju)电(dian)(dian)路来(lai)升压。

常用(yong)自(zi)(zi)举(ju)电(dian)(dian)路(lu)（摘(zhai)自(zi)(zi)fairchild，使用(yong)说明书AN-6076《供高电(dian)(dian)压栅极驱(qu)动器IC 使用(yong)的(de)自(zi)(zi)举(ju)电(dian)(dian)路(lu)的(de)设计和使用(yong)准则》），开(kai)关直流升压电(dian)(dian)路(lu)（即所(suo)谓的(de)boost或者step-up电(dian)(dian)路(lu)）原理，the boost converter，或者叫step-up converter，是(shi)一种开(kai)关直流升压电(dian)(dian)路(lu)，它可以(yi)是(shi)输出电(dian)(dian)压比(bi)输入电(dian)(dian)压高。基本电(dian)(dian)路(lu)图(tu)见(jian)图(tu)1.

二极管升压电路

假定那个开关（三极管或者mos管）已(yi)经断开了(le)很长时间，所有的元件(jian)都(dou)处于(yu)(yu)理想状(zhuang)态，电(dian)容电(dian)压等于(yu)(yu)输入电(dian)压。下面要(yao)分(fen)充电(dian)和放电(dian)两个部分(fen)来说明这个电(dian)路。

（1）充电过程

升压电(dian)(dian)(dian)(dian)(dian)路(lu)原理的充电(dian)(dian)(dian)(dian)(dian)过程(cheng)，在(zai)充电(dian)(dian)(dian)(dian)(dian)过程(cheng)中，开(kai)关(guan)闭合(he)(三极(ji)管导(dao)通(tong))，等(deng)效电(dian)(dian)(dian)(dian)(dian)路(lu)如图二(er)，开(kai)关(guan)(三极(ji)管)处用导(dao)线(xian)(xian)代(dai)替。这时，输入(ru)(ru)电(dian)(dian)(dian)(dian)(dian)压流(liu)过电(dian)(dian)(dian)(dian)(dian)感(gan)。二(er)极(ji)管防止电(dian)(dian)(dian)(dian)(dian)容对地放电(dian)(dian)(dian)(dian)(dian)。由(you)于(yu)输入(ru)(ru)是直流(liu)电(dian)(dian)(dian)(dian)(dian)，所以电(dian)(dian)(dian)(dian)(dian)感(gan)上(shang)的电(dian)(dian)(dian)(dian)(dian)流(liu)以一定的比(bi)率线(xian)(xian)性(xing)增(zeng)加，这个(ge)比(bi)率跟电(dian)(dian)(dian)(dian)(dian)感(gan)大小有关(guan)。随(sui)着电(dian)(dian)(dian)(dian)(dian)感(gan)电(dian)(dian)(dian)(dian)(dian)流(liu)增(zeng)加，电(dian)(dian)(dian)(dian)(dian)感(gan)里储存了一些能量。

二极管升压电路

（2）放电过程

升压(ya)(ya)电(dian)(dian)(dian)路原理(li)的(de)(de)(de)放电(dian)(dian)(dian)过程。如图，这是当(dang)开(kai)关断开(kai)(三极(ji)管(guan)(guan)截止)时的(de)(de)(de)等效电(dian)(dian)(dian)路。当(dang)开(kai)关断开(kai)(三极(ji)管(guan)(guan)截止)时，由(you)(you)于电(dian)(dian)(dian)感(gan)的(de)(de)(de)电(dian)(dian)(dian)流(liu) 保持特(te)性，流(liu)经(jing)电(dian)(dian)(dian)感(gan)的(de)(de)(de)电(dian)(dian)(dian)流(liu)不会(hui)马上变(bian)为0，而是缓慢(man)的(de)(de)(de)由(you)(you)充电(dian)(dian)(dian)完(wan)(wan)毕时的(de)(de)(de)值变(bian)为0。而原来的(de)(de)(de)电(dian)(dian)(dian)路已(yi)断开(kai)，于是电(dian)(dian)(dian)感(gan)只能通(tong)过新电(dian)(dian)(dian)路放电(dian)(dian)(dian)，即电(dian)(dian)(dian)感(gan)开(kai)始给电(dian)(dian)(dian)容(rong)充电(dian)(dian)(dian)，电(dian)(dian)(dian)容(rong)两(liang)端电(dian)(dian)(dian)压(ya)(ya)升高(gao)，此时电(dian)(dian)(dian)压(ya)(ya)已(yi)经(jing)高(gao)于输入电(dian)(dian)(dian)压(ya)(ya)了，升压(ya)(ya)完(wan)(wan)毕。

二极管升压电路

升压(ya)过(guo)程就(jiu)是一个电感的能量传递过(guo)程。充(chong)电时(shi)(shi)，电感吸收能量，放电时(shi)(shi)电感放出能量。如果(guo)电感量足够大(da)，那么在(zai)(zai)输出端(duan)就(jiu)可以在(zai)(zai)放电过(guo)程中保持一个持续的电流。如果(guo)这个通断(duan)的过(guo)程不断(duan)重复，就(jiu)可以在(zai)(zai)电容(rong)两端(duan)得到高(gao)于输入电压(ya)的电压(ya)。

二极管升压电路

电容二极管升压电路分析

二极管升压电路

当电路未通电时，各处电平都(dou)是(shi)0V。

二极管升压电路

当通(tong)电(dian)时(shi)，右上角(jiao)+5V_ALWP通(tong)过(guo)D32的(de)1引脚对C710、C722、C715、C719进行(xing)充电(dian)，此(ci)时(shi)电(dian)容上两端的(de)电(dian)位如上图所示(shi)。此(ci)时(shi)+15V_ALWP输出(chu)端口的(de)实际电(dian)平为5V。

二极管升压电路

当U64的(de)Y引脚开始输(shu)出幅值为5V的(de)方波(bo)，当Y第一次处于(yu)5V电位时：

1.由(you)于电(dian)容(rong)两(liang)端的电(dian)压(ya)不能突变，此(ci)时C715两(liang)端的电(dian)压(ya)为左边5V，右边为10V，然(ran)后(hou)电(dian)流经过(guo)D35的2引脚对C719电(dian)容(rong)充(chong)电(dian)，充(chong)完电(dian)后(hou)C719的电(dian)压(ya)升到(dao)了10V。

2.同时，Y输出的5V也对(dui)C710进行充电(dian)(dian)(dian)，C710两端的电(dian)(dian)(dian)压为(wei)左边5V，右边为(wei)10V，然后电(dian)(dian)(dian)流(liu)经过D32的2引脚对(dui)C722进行充电(dian)(dian)(dian)，充完电(dian)(dian)(dian)后C722的电(dian)(dian)(dian)压升到了10V。

此时+15V_ALWP输出端口的实际电(dian)平为(wei)10V。

二极管升压电路

当U64的Y引脚开(kai)始输出(chu)幅值(zhi)为5V的方波，当Y第一次处于0V电位(wei)时：

1.由(you)(you)于电容两端的(de)电位不能(neng)突变，此(ci)时(shi)C715两端的(de)电压(ya)为(wei)左边0V，右边5V。当C715电压(ya)为(wei)5V后，由(you)(you)于C722电压(ya)10V大(da)于C715的(de)5V，C722会(hui)对C715充电。充电后C715=C722=7.5V。此(ci)时(shi)C715的(de)电压(ya)依(yi)然比(bi)C719的(de)电压(ya)低。但(dan)是由(you)(you)于D32二极管反向截止，所以(yi)C719不会(hui)对C715充电。C719的(de)电压(ya)保持在10V。

2.同(tong)时，C710的电压(ya)为(wei)左边(bian)0V，右(you)边(bian)5V，C722的左端电压(ya)为(wei)7.5V，由(you)于D32的2引脚(jiao)的反向(xiang)截止(zhi)，C722依然不会对C710充电，C722保持在7.5V。

当(dang)Y第二次(ci)处于5V时，C722通过(guo)C710、D32的(de)2引(yin)脚又(you)被充(chong)电(dian)(dian)为(wei)(wei)10V。当(dang)Y又(you)处于低电(dian)(dian)平(ping)时，C722（10V）对C715（7.5V）充(chong)电(dian)(dian)。C715的(de)电(dian)(dian)压变(bian)为(wei)(wei)8.75V。经过(guo)数次(ci)过(guo)程(cheng)后，C715两端的(de)电(dian)(dian)压差上(shang)升为(wei)(wei)了(le)10V，当(dang)Y再次(ci)为(wei)(wei)5V时，C715的(de)右端的(de)电(dian)(dian)位(wei)变(bian)为(wei)(wei)了(le)15V。当(dang)然，在

整个过(guo)程中，C715都在通过(guo)D35的2引脚向C719充电。

最终+15V_ALWP输出端口(kou)的电(dian)平变为(wei)了15V。

两种发光二极管升压电路-自制LED手电筒

发光二极管升压电路（一）

二极管升压电路

发光二极管升压电路（二）

节(jie)干电(dian)(dian)(dian)池电(dian)(dian)(dian)压(ya)是1.5伏，达(da)不(bu)到发光二(er)极管(guan)的(de)导通电(dian)(dian)(dian)压(ya)（大约2.5伏），不(bu)能(neng)让二(er)极管(guan)发光，因此必须用一个(ge)升(sheng)压(ya)电(dian)(dian)(dian)路(lu)。除了(le)发光二(er)极管(guan)只要2个(ge)电(dian)(dian)(dian)子元件就(jiu)够了(le)完成后的(de)电(dian)(dian)(dian)路(lu)如下图：1个(ge)电(dian)(dian)(dian)感线圈、1个(ge)电(dian)(dian)(dian)阻、1个(ge)三极管(guan)、1个(ge)发光二(er)极管(guan)、1节(jie)干电(dian)(dian)(dian)池，焊接在一起，二(er)极管(guan)就(jiu)能(neng)够发光了(le)。

二极管升压电路