模块电源的功率密度高,这时业界公认的.但功率提高的同时,自身的散热就成了问题,当然,我们可以通过提高效率等等途径进行改进,但并不是每一款电源都能大幅度提升的.
小弟是刚刚入行模块电源的人,有很多不懂的地方,需要像各DX们请教,万望各位DX不要吝啬,大家共同探讨,共同提高.
前些天在实验一块模块的时候,功率并不高,只有100W,Vin24V Vout5V,采用单管正激电路,使用的是UC3843B芯片控制,没有采用有源嵌位和同步整流,工作频率300KHZ,发现它并不能长期实际工作在100W,长期工作的话,会使MOSFET或者次级二极管击穿,应该是热击穿,现在,我想能不能想办法让它可以长期工作在100W下,模块尺寸82*56*15mm
曾经试过:1 增加MOSFET,使用多MOSFET并联,当然,驱动也有更改,3843B驱动不了多MOSFET,但是效果并不好,增加了成本,还没解决问题.多个MOSFET并不能同时导通,总会有先有后,所以总是会有一个MOSFET击穿.
2 增加次级二极管,使用多个并联,效果与方案1类似,也不理想.
小弟实在是没法子了,各位DX帮忙出个主意吧.
(因空间限制,加散热片不现实,)
关于模块电源散热的问题
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@dadodo
5V100W输出20A电流,次级还用二极管整流?发热很厉害的,换同步整流吧.输入24V平均5A电流,不是太差的MOS管都能胜任,那用得着多个并呢?
首先谢谢dadodo的回复,UC3843B的驱动峰值电流1A,我已经把驱动电路更改了,改成用3843驱动两个对管,对管接的自供电,然后驱动MOSFET的,应该不是驱动能力不足吧?
如果换成同步整流,我对同步整流没接触过,曾经试过用电压自驱动的方式,但是效果很不理想,空载的输入电流很大,并且有的时候,续流MOSFET会被击穿,换成IC驱动的,因为成本问题,老板一直没通过,真不知道该如何是好了.
如果换成同步整流,我对同步整流没接触过,曾经试过用电压自驱动的方式,但是效果很不理想,空载的输入电流很大,并且有的时候,续流MOSFET会被击穿,换成IC驱动的,因为成本问题,老板一直没通过,真不知道该如何是好了.
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@化生
嗯,我也是这么想的,但是问题的关键是即使换成同步整流技术,效率也不可能在提高多少了,我现在已经90%左右了,大多数达到89%.用同步整流效率不会更高多少了,那样还是有很大的损耗,散热还是问题
My personal suggestion: pick-up ideas form your compaitors is the best way!! Especially the world-wide brands, their products has a lot of solutions! Once you solved it then back to tell us your result! good luck!
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@化生
汗......教我去借鉴别人的方法啊?但是每个R&D的设计思路不一样啊,这样就像是大海里捞针,困难重重.
The same as you came here to get other engineers' advices!
Actually you have to see some good products or well designs then you can got so many ideas for your design! Every long-standing products are have a lot of wisedom in it! Not olny you even me also pick-up ideas form others! It isn't copy, You have to implement that idea into your case solve your problem, you have to over-come some difficults then done! For this case: if you don't change the circuit then you have two ways only: one is better components(SIC?) the other one is heat-sink(mini-size? copper attach? or better potting?) the gap is "因空间限制,加散热片不现实" You have to add some kind of 散热片!!
Actually you have to see some good products or well designs then you can got so many ideas for your design! Every long-standing products are have a lot of wisedom in it! Not olny you even me also pick-up ideas form others! It isn't copy, You have to implement that idea into your case solve your problem, you have to over-come some difficults then done! For this case: if you don't change the circuit then you have two ways only: one is better components(SIC?) the other one is heat-sink(mini-size? copper attach? or better potting?) the gap is "因空间限制,加散热片不现实" You have to add some kind of 散热片!!
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@temp1234
Thesameasyoucameheretogetotherengineers'advices!Actuallyyouhavetoseesomegoodproductsorwelldesignsthenyoucangotsomanyideasforyourdesign!Everylong-standingproductsarehavealotofwisedominit!Notolnyyouevenmealsopick-upideasformothers!Itisn'tcopy,Youhavetoimplementthatideaintoyourcasesolveyourproblem,youhavetoover-comesomedifficultsthendone!Forthiscase:ifyoudon'tchangethecircuitthenyouhavetwowaysonly:oneisbettercomponents(SIC?)theotheroneisheat-sink(mini-size?copperattach?orbetterpotting?)thegapis"因空间限制,加散热片不现实"Youhavetoaddsomekindof散热片!!
您的建议非常好!!!其实我不光是这款产品有散热问题要解决,我大多数产品都多多少少会有这方面的问题,与其一点点的探索,不如直接站在别人的肩膀上.
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@化生
您的建议非常好!!!其实我不光是这款产品有散热问题要解决,我大多数产品都多多少少会有这方面的问题,与其一点点的探索,不如直接站在别人的肩膀上.
Yes! Especially, Standing on a Giant shoulder may better! But You have to be very carefully on patent trips! They also protect their property well! By the way, you are wellcome to discussion on your ideas!
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