我最近設(shè)計一款小功率電源.波形也很好,就是測量波形時發(fā)現(xiàn)占空比總是變.特別是在低壓的時候.我電源的各項功能也都正常.我的理解是在輸入低壓的時候,電源的波動所造成的,不知道對不.我想請教各位大俠們指點 一二.
兄弟多謝了!!!
多謝指點!
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兄弟將電路圖原理上傳.1169273912.pdf
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@baixiang
兄弟將電路圖原理上傳.1169273912.pdf
at 90Vac input, 60Hz
peak input voltage is 127Vdc
your cap=33uF
after charge of your input cap, the energy for the operation will come from capacitor, therefore, lowest voltage on the capacitor is Vl
1/2*33u*(127^2-Vl^2)=18W*8mS
Vl=86V
therefore your measured ripple voltage on 33uF cap is 127V-86V=41V
If the variation of Duty cycle only happen in the Low input voltage and full load, most probably caused by the ripple on our input capacitor. This is normal, otherwise, you will seethe ripple on the output voltage.
peak input voltage is 127Vdc
your cap=33uF
after charge of your input cap, the energy for the operation will come from capacitor, therefore, lowest voltage on the capacitor is Vl
1/2*33u*(127^2-Vl^2)=18W*8mS
Vl=86V
therefore your measured ripple voltage on 33uF cap is 127V-86V=41V
If the variation of Duty cycle only happen in the Low input voltage and full load, most probably caused by the ripple on our input capacitor. This is normal, otherwise, you will seethe ripple on the output voltage.
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@bud_guy
at90Vacinput,60Hzpeakinputvoltageis127Vdcyourcap=33uFafterchargeofyourinputcap,theenergyfortheoperationwillcomefromcapacitor,therefore,lowestvoltageonthecapacitorisVl1/2*33u*(127^2-Vl^2)=18W*8mSVl=86Vthereforeyourmeasuredripplevoltageon33uFcapis127V-86V=41VIfthevariationofDutycycleonlyhappenintheLowinputvoltageandfullload,mostprobablycausedbytherippleonourinputcapacitor. Thisisnormal,otherwise,youwillseetherippleontheoutputvoltage.
多謝指點!兄弟不勝感激!我沒有機會在哪一家公司干了.他們不讓我在那里了.以后能同你聯(lián)系嗎?我的QQ號碼:723732132
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@bud_guy
at90Vacinput,60Hzpeakinputvoltageis127Vdcyourcap=33uFafterchargeofyourinputcap,theenergyfortheoperationwillcomefromcapacitor,therefore,lowestvoltageonthecapacitorisVl1/2*33u*(127^2-Vl^2)=18W*8mSVl=86Vthereforeyourmeasuredripplevoltageon33uFcapis127V-86V=41VIfthevariationofDutycycleonlyhappenintheLowinputvoltageandfullload,mostprobablycausedbytherippleonourinputcapacitor. Thisisnormal,otherwise,youwillseetherippleontheoutputvoltage.
我忘記告訴你了.我在低壓時各項性能都正常.
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