Power supply design 12v (350w)

[shaltera]

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

 

[kam1787]

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?

 

[shaltera]

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)

- - - Updated - - -

Proteus DB does not have a voltage regulator with such a rate (max is 2A)

 

[kam1787]

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

 

[kam1787]

https://www.eleccircuit.com/high-current-12v-30a25a20a15a-ham-radio-power-supply/
https://www.circuitstoday.com/12v-15a-voltage-regulator
**broken link removed**

or using a zener

https://www.circuitstoday.com/regulated-dc-power-supply

 

[shaltera]

I tried to simulate examples with transistors but maximum output current I have managed to get was 2.5A.