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Voltage Regulator Selection

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Loaded4th

New Member
Hi;

I have not dabbled much with electronics for a number of years, even though I used to be rather proficient. Currently, I'm thinking of building a power supply of 1 to 28v at around 5A.

I noticed that there are a number of different regulators such as the:


LM1084IT-ADJ 5A low dropout VR

LM2588T-ADJ 5A flyback VR w/shutdown

LM723 150mA adj + 2N3055 o/p for higher current.


Is any one device better than another or is it a question of cost and use?

thanks in advance...
 

audioguru

Well-Known Member
Most Helpful Member
For a max output of 28V the unregulated supply must be about 32VDC. If the max current is 5A and the output is set to a low voltage or is shorted then the series pass device must dissipate 160W!

One 2N3055 transistor is rated at 115W if its case is cooled to 25 degrees C somehow (liquid nitrogen?) but will be extremely hot at only 60W even if it has a huge heatsink.

Think about switching taps on the transformer so that the series pass device does not have a high voltage across it when the output voltage is set to a low voltage. Maybe automatic switching.
Or think about paralleling a few series pass devices to share the heat.
 

Loaded4th

New Member
Thanks for the response.

I'm aware of input voltage variation and heat issues. I was actually trying to get some advice on a particular [integrated] voltage regulator.

 
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