500) {this.resized=true; this.width=500; this.alt='这是一张缩略图,点击可放大。\n按住CTRL,滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/76/2504931239161326.jpg?x-oss-process=image/watermark,g_center,image_YXJ0aWNsZS9wdWJsaWMvd2F0ZXJtYXJrLnBuZz94LW9zcy1wcm9jZXNzPWltYWdlL3Jlc2l6ZSxQXzQwCg,t_20');}" onmousewheel="return imgzoom(this);">
上图是飞思卡尔数字电源的方案,这里表示的是DC-DC的全桥拓扑,后面是同步整流,从图来看应该是全波同步整流,但是没做过同步整流,还请高手解释一下这张图同步整流的原理,并且我有个疑惑,如果负载开路,难道L1和L2不会造成变压器原边短路.还请高手支招!
关于数字方式控制的同步整流的问题(有图)??
全部回复(7)
正序查看
倒序查看
现在还没有回复呢,说说你的想法
@周挺巧
正半波过来时Q6导通Q5断开L11进入储能过程同时对C(C几看不清楚),负半波过来时Q6断开Q5导通L11进入续流状态,同时L12进入储能过程.如此循环
500) {this.resized=true; this.width=500; this.alt='这是一张缩略图,点击可放大。\n按住CTRL,滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/76/2504931239180983.jpg');}" onmousewheel="return imgzoom(this);">
As shown in Figure 6-5, the control of the synchronous rectifier is derived from the DC/DC converter
main switches’ signals. To avoid short circuiting the transformer when voltage is established, the
synchronous rectifier must turn off when the switch in the lag leg turns on. Also, to avoid the current
flows from the synchronous rectifier’s body diode, it must turn on when the lead leg switches on. But to
avoid a short circuit, there must be a delay time between the rectifier’s turn on and the lead leg’s turn off.
上面的图以及后面的描述怎么理解,如果时序不对,变压器短路是怎么造成的?
As shown in Figure 6-5, the control of the synchronous rectifier is derived from the DC/DC converter
main switches’ signals. To avoid short circuiting the transformer when voltage is established, the
synchronous rectifier must turn off when the switch in the lag leg turns on. Also, to avoid the current
flows from the synchronous rectifier’s body diode, it must turn on when the lead leg switches on. But to
avoid a short circuit, there must be a delay time between the rectifier’s turn on and the lead leg’s turn off.
上面的图以及后面的描述怎么理解,如果时序不对,变压器短路是怎么造成的?
0
回复
提示
@cailiang00
[图片]500){this.resized=true;this.width=500;this.alt='这是一张缩略图,点击可放大。\n按住CTRL,滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}"onclick="if(!this.resized){returntrue;}else{window.open('http://u.dianyuan.com/bbs/u/76/2504931239180983.jpg');}"onmousewheel="returnimgzoom(this);">AsshowninFigure6-5,thecontrolofthesynchronousrectifierisderivedfromtheDC/DCconvertermainswitches’signals.Toavoidshortcircuitingthetransformerwhenvoltageisestablished,thesynchronousrectifiermustturnoffwhentheswitchinthelaglegturnson.Also,toavoidthecurrentflowsfromthesynchronousrectifier’sbodydiode,itmustturnonwhentheleadlegswitcheson.Buttoavoidashortcircuit,theremustbeadelaytimebetweentherectifier’sturnonandtheleadleg’sturnoff.上面的图以及后面的描述怎么理解,如果时序不对,变压器短路是怎么造成的?
不错!有新的发现!!!!! 这电路设计得很巧,由于移相是PWM是由MCU提供的,MCU理所当然可以准确的将同步整流信号提供给同步整流MOS管,而不必像其它同步IC需要检测电路电流.不知这芯片多少钱?如果贵的话我们同样可以将这功能移植到其它MCU上.另:你说的哪两个电感是倍流电路典型应用电路了,电源网上已发很多了.查查看吧!!!
0
回复
提示