Switching Power Supply

[maxweber]

Hello there! I have to design a Source that is able to provide 48V 3A. I was wondering if you could help me choose the right DC-DC converter topology. Push-pull, Half-bridge, or Full-bridge. I understand the three of them are based on the Buck converter. But I don't know which one would be more suitable for the requirements I've been given! Kind regards!

 

[fethiyeli]

It changes according to your desired output power. Half-bridge can be used up to 1.5kW, in the case of more power, you need to select full-bridge. Push-pull can be used in any power as ı know but it has disadvantages as well. Although there are some disadvantages, your output power seems to be suitable for push pull topology. You can use these good websites as well,

 

[kam1787]

what is the input? From where are you getting the power?

 

[maxweber]

Thanks to both of you! I have read that push-pull has many disadvantages! The input is the voltage provided by the line! I mean it is 220V AC.

The thing is, I've been reading some books and all they focus on is the DC-DC Converter part, not the whole system! So I really don't know which IC to use for the control part for instance.

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Thanks! The input is the voltage provided by the line! I mean it is 220V AC!

 

[fethiyeli]

Your AC line signal must be rectified as 311VDC which will be converted into 48VDC via DC-DC converter circuit. Common ICs are, TL494,SG3525,UC3842-UC3845. UC series are commonly used when adjustable output is necessary. You should also use EMI filter before rectification and output voltage must be provided from line. Other topologies are not different about providing voltage from line.

 

[pol]

what does EMI filter mean???

 

[fethiyeli]

EMI means Electromagnetic Interference. It occurs due to high frequency switching signals from SMPS and it should be blocked by filters.