switching made power supply

[oscarelk]

could anyone help me to modify a PC power supply to use as a multi purpose power supply.
I'need switching made (portable,light weight)adjustable power supply to use between voltages 1,5 and 15 volts.
plesa anyone help me about that?
prefix schemes or intruductions are enough for me.
thanks for your interest in advance

 

[mohsenruz]

To design and build a new power supply with this specification is easier than to change a pc power supply for your purpose. as you know pc supplies are constant power supplies and there is no unique design for them. just may be you can dis assemble the components and use some of them in your disign

 

[xjackal]

i am also working on a sample project like that and im using pic kontroller.the power supply controls its output with pwm pulses by pic.i can send the scheme later.and its better u start from here.hope this helps. :wink:

 

[devonsc]

Hi oscarelk,

Is it a must for you to modify one? Is this a must as in, the requirements of a project or something?

If no, you might want to consider developing a power supply unit from scratch. I had just developed a unit something like what xjackal is working on at the moment. I actually used the PIC microcontroller to provide the PWM pulse to the MOSFETs as well.

 

[bomba]

I'm using a PC power supply like variable desktop power supply, you must to put in the Vref of the controller IC an variable resistor, test the value range that produce change in the output voltage, in the final version you must to use a resistor configuration that satisfied the test.
You must be careful with the over tension protection there some kind of PC power supply that can source more than 15 Volt but other block output with 15 V. you can disable this protection or use under the protection.

Best regards

 

[atlantis83]

I think you can build a flyback converter easily to handle this problem

 

[oscarelk]

Seems it'll be easier and more stable to make one from beginning.

Thanks all friend for spending time for their answers. But...
I'll request one more thing if possible.

I'll need a scheme (Switch mode) to build one. I made search but I couldnt find a one that gives variable output.

Could anyone send me a scheme if possible?
Thank for all for interest.