上圖是飛思卡爾數(shù)字電源的方案,這里表示的是DC-DC的全橋拓?fù)?后面是同步整流,從圖來(lái)看應(yīng)該是全波同步整流,但是沒(méi)做過(guò)同步整流,還請(qǐng)高手解釋一下這張圖同步整流的原理,并且我有個(gè)疑惑,如果負(fù)載開(kāi)路,難道L1和L2不會(huì)造成變壓器原邊短路.還請(qǐng)高手支招!
關(guān)于數(shù)字方式控制的同步整流的問(wèn)題(有圖)??
上圖是飛思卡爾數(shù)字電源的方案,這里表示的是DC-DC的全橋拓?fù)?后面是同步整流,從圖來(lái)看應(yīng)該是全波同步整流,但是沒(méi)做過(guò)同步整流,還請(qǐng)高手解釋一下這張圖同步整流的原理,并且我有個(gè)疑惑,如果負(fù)載開(kāi)路,難道L1和L2不會(huì)造成變壓器原邊短路.還請(qǐng)高手支招!
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@周挺巧
正半波過(guò)來(lái)時(shí)Q6導(dǎo)通Q5斷開(kāi)L11進(jìn)入儲(chǔ)能過(guò)程同時(shí)對(duì)C(C幾看不清楚),負(fù)半波過(guò)來(lái)時(shí)Q6斷開(kāi)Q5導(dǎo)通L11進(jìn)入續(xù)流狀態(tài),同時(shí)L12進(jìn)入儲(chǔ)能過(guò)程.如此循環(huán)
500) {this.resized=true; this.width=500; this.alt='這是一張縮略圖，點(diǎn)擊可放大。\n按住CTRL，滾動(dòng)鼠標(biāo)滾輪可自由縮放';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.
上面的圖以及后面的描述怎么理解,如果時(shí)序不對(duì),變壓器短路是怎么造成的?
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@cailiang00
[圖片]500){this.resized=true;this.width=500;this.alt='這是一張縮略圖，點(diǎn)擊可放大。\n按住CTRL，滾動(dòng)鼠標(biāo)滾輪可自由縮放';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.上面的圖以及后面的描述怎么理解,如果時(shí)序不對(duì),變壓器短路是怎么造成的?
不錯(cuò)!有新的發(fā)現(xiàn)!!!!! 這電路設(shè)計(jì)得很巧,由于移相是PWM是由MCU提供的,MCU理所當(dāng)然可以準(zhǔn)確的將同步整流信號(hào)提供給同步整流MOS管,而不必像其它同步IC需要檢測(cè)電路電流.不知這芯片多少錢(qián)?如果貴的話我們同樣可以將這功能移植到其它MCU上.另:你說(shuō)的哪兩個(gè)電感是倍流電路典型應(yīng)用電路了,電源網(wǎng)上已發(fā)很多了.查查看吧!!!
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