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need design a switch power suply with 12 V and 5 A out put.

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ymq8328

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the input is 220 V AC , the output is 12 V and 5 A in DC model .
any advices qre good. thanks
 

Re: need design a switch power suply with 12 V and 5 A out p

You didnt specified the current requirement??
Normal power supply design

Stepdown Transformer -> Bridge rectifier -> voltage regulator IC

for 5V you can see 7805 and for 12 - 7812
Be sure to see if the current ratings are as per your requirement

You can refer the below links too
**broken link removed**
http://www.geocities.com/JDPetkov/Hardware/power/power.htm
 

Re: need design a switch power suply with 12 V and 5 A out p

Here you have an example of 220ac/12Vdc smps:
**broken link removed**
However, if you don't feel confident about HV ferrite transformers then you should consider a step-down transformer 220/24Vac + bridge + smoothing cap, and a switchmode dc/dc converter build around sme 5A IC, such as for example LM2768: **broken link removed** , or similar ..
Regards,
IanP
 

when I used this soluton :Stepdown Transformer -> Bridge rectifier -> voltage regulator IC . the IC(7812) is too hot.

Added after 1 minutes:

I kown switch power suply is a good solution , but I kown nothing about it .
 

Re: need design a switch power suply with 12 V and 5 A out p

Keep in mind that the 7812 voltage regulator is rated only for 1A of the output current.
If you want to go for a linear regulator you can use 7812 + external power transistor (see LM7812/340 data sheet: http://info.hobbyengineering.com/specs/LM340.pdf ) to boost the current, or you can select LM338 which is a 5A linear voltage regulator.
In all cases you have to mount these power components (votage regulators and power transistors) on a reasonable size heatsinks ..
Regards,
IanP
 

I think using the lm338 is a good choice,thanks
 

Re: need design a switch power suply with 12 V and 5 A out p

The MAX724 is very easy to use; I think you should have a look at it!
 

yes ,MAX724 is very easy to use; but I think it is too expensive . the topic also need help. because i can't buy the chip lm338 in our country. I think to use some separate chips is a good choice. thanks
 

Re: need design a switch power suply with 12 V and 5 A out p

Most likely you can buy 7812 and a PNP power transistor.
In this case you can boost the output current by connecting this PNP tansitor to 7812 voltage regulator in the attached configuration (picture shows 7805 but for 7812 priciple and components are exactly the same) ..
Regards,
IanP
 

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    ymq8328

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Re: need design a switch power suply with 12 V and 5 A out p

HI
If you have a closer look at the previous link I posted
**broken link removed**

In this link they have used power trasnistors and the circuit can source 30A which I think will be far more than your requirement so you can reduced the number of transistors also
 

Re: need design a switch power suply with 12 V and 5 A out p

ymq8328 said:
the input is 220 V AC , the output is 12 V and 5 A in DC model .
any advices qre good. thanks
Click to expand...

Suggest you visit Power Integration site at www.powerint.com and download their PI Experts suite. This software will let you spped up the design of a SMPS. There are also many application notes and engineering reports including PCB layouts.

At www.onsemi.com you can download a limited version of POWER 1-2-3 this also will let you design and SIMULATE.

Good Luck !!!
 

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