我最近设计一款小功率电源.波形也很好,就是测量波形时发现占空比总是变.特别是在低压的时候.我电源的各项功能也都正常.我的理解是在输入低压的时候,电源的波动所造成的,不知道对不.我想请教各位大侠们指点 一二.
兄弟多谢了!!!
多谢指点!
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@baixiang
兄弟将电路图原理上传.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.
多谢指点!兄弟不胜感激!我没有机会在哪一家公司干了.他们不让我在那里了.以后能同你联系吗?我的QQ号码: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.
我忘记告诉你了.我在低压时各项性能都正常.
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