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Power supply design 12v (350w)

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shaltera

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Hello everyone,

I'm struggling to design a power supply with following specifications

Vin=240VAC, 50Hz
Vout=12Vdc
Power = 350W
Output ripple voltage <5%

I have converted 240V ac to 12V dc, using TR,Bridge rectifier and voltage regulator.However the main problem is 350W output on the dc.

I was thinking of using a Zener diode connected to NPN Power transistor,but not quite sure where is possible

Any help appreciated.

Thank you in advance
 

There is no filter capacitor after the rectifier?

350W for the output is almost THIRTY amps! If you have a regulator why do you need a series zener based regulator?
 

In the power supply (with voltage regulator) I use a capacitor as a filter (after bridge rectifier).

I was thinking of alternative way with Zener diode and NPN (schematic attached) im.jpg

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Proteus DB does not have a voltage regulator with such a rate (max is 2A)
 
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and you want 30A at 12VDC?

I think C1 is too low, some use a rule-of-thumb of 1000uF per amp, other say 2000uF per amp

you need at least 2 3055 in parallel

you would 'have to' buffer the zener with another transistor

I would put a capacitor across the zener [cap multiplier to reduce the ripple] - say 1000uF

The 1n4742 is a 12V zener diode? Because of the voltage drop across Q1 you will get less Vout - around 11.3V
 
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I tried to simulate examples with transistors but maximum output current I have managed to get was 2.5A.
 

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