I am creating a regulated 3.4 Volts 5 Amp DC supply from 24 volts 5Amp DC supply, now the problem is that when I use a load of 2 amp the transistors start heating up and then burnt out even I m using heat sinks, due to heavy power dissipation on transistor.I m attaching a schematic of my regulator supply,kindly check it and help me out.I have to dirve a load about 5 amp.

Attached Images

untitled.JPG (15.1 KB, 23 views)

 

Linear regulator scheme is very poor as you are wasting 20.6W as heat for every ampere you put into the load. Under a 5A loading, that's more than 100W. The voltage difference are too great and the current too high.

Either use a huge heatsink or use switch mode PS instead.

__________________
L.Chung

 

can u plz give me a circuit diagram of such power supply dat can provide 3.4 volts and 5 Amps.plzzzzzzzz n thnx for da rep i will try ur suggestion.

 

Great, another 'plzzzzzz giv me ckt' person.

I certainly won't design it for you but if you enter the input and output voltage and the current you plan to draw into the wizards I've linked you to, they'll design it for you.

http://www.linear.com/pc/viewCategor...C1,C1003,C1042
http://www.national.com/appinfo/power/

__________________
I also post at the following sites:
http://www.stop-microsoft.org http://www.heated-debates.com
Screen name: Aloone_Jonez

 

how is that regulated when there is no feedback from the output?

 

The output voltage is regulated within about 1V.
A voltage regulator IC regulates the output to within about 10mV, which is 100 times better.

__________________
Uncle $crooge

 

Yes there is, infact 100% of the output (Rl) is fed back to the input (the base).

As the emitter voltage rises, the base terminal is lifted up in the opposite direction of the input current from the zener shunt regulator.

__________________
I also post at the following sites:
http://www.stop-microsoft.org http://www.heated-debates.com
Screen name: Aloone_Jonez