How to make a +/- supply for a positive input?

[wossy]

Hi

I want to make a +5V,0V,-5V supply from a positive input, probably +12V. I have heard that I can just do it with a couple of adj regulators. If I have one set to 5V and the other set to 10V I think that should work. But how do I connect the two reg together. Do do grounds of each reg connect to each other or somewhere else?


Thanks

W

 

[IanP]

Re: +/- Supply

Drop off 2 volts of the 12V supply by using 3 standard silicone diodes (1N400X) and implement so called virtual ground circuit to create +/-5V supply ..
Examples of virtual ground you can find here:
https://tangentsoft.net/elec/vgrounds.html
Regards,
IanP

 

[VVV]

Re: +/- Supply

You can do it with two regulators, just like you were suggesting, although I prefer the opamp approach.

To answer your question, the two regulators will have the same ground, which in fact will be your -5V. The output of the 5V regulator will be your "ground" and the output of the 10V regulator will be your new +5V.

 

[master_slave]

Re: +/- Supply

You can also use the Microchip TC7660 dc-dc converter to provide bipolar supply voltages. All you need is the 5V regulator, this IC plus a handful of capacitors and you will have +5V, 0V and -5V.