How can I build tracking bench supply from SMPS

[Graygem]

Hello,
I have a 800 watt ±70V SMPS and was wondering how hard it would be to build a dual tracking bench power supply out of it.
Can anyone help?
Thank you

 

[ronsimpson]

+/- 70V 1A supply.
How is it not a bench supply?
What do you want it to do?
Do you want meters? V and A?

 

[Graygem]

It is just a bare smps. I need an adjustable 0 to ±70V. And yes, I would like the readout of voltage and current.

 

[ronsimpson]

I would get some of these.

Do you have a schematic for your supply?
One idea is to get the smps to go 0 to 70 volts. It probably will not be easy.
Idea 2 is to add a linear or smps on the output that takes the 70v and makes 0 to 65 volts.

 

[crutschow]

What is the SMPS you have?

 

[dr pepper]

Do you have a schematic, or at least the type of controller chip it uses if it has one.

 

[4pyros]

Ya lets hack a +/-70 volt SMPS!

 

[dr pepper]

Roughly translated - only do something like this if your reasonably competant.

 

[Graygem]

The SMPS is actually a SMPS800RE from Connexelectronic. It is their ±72v version with a ±15v auxilary.

 

[ronsimpson]

Most smps will not be happy changing the error amplifier to make it go down to 5 volts.
I think you should make a buck converter to take the 72 volts down to (0 to 65V)
Picture:

 

[dr pepper]

If you went from 72v to 5v you wouldnt get anything like the 800 watts, for that you'd have to do some drastic stuff like rewind the inductor and replace the recitifiers/output inductors and beef up the tracks.
Rons suggestion is better.

 

[Graygem]

Here I thought it would be easy. My thought was to build a circuit that would take the output from the smps and adjust that, instead of modifying the smps itself.