12V-12V converter!

Maybe a boost converter that uses a 12 volt battery and providing a 12 volt output, boosting the voltage so you can get 12V regulated out of

For a 12V battery you could use either a Sepic or a buck boost. These topologies can either buck or boost the output voltage as requiried to maintain 12V.

Do you need it to be isolated?

For non isolated, you can use a SEPIC converter or:

P-MOSFET ---- --------+-------)))))------+------->!----- Load ! ! ! ! ! =3D=3D=3D=3D=3D --- !!- ! ^ B---!!- N-MOSFET ! ! !!--GND A GND

At 12V AB and B can be driven by a level shifting driver. The logic can be all put in a small PIC.

Linear makes a chip that does it with two N-MOSFETs.

Do you mean +12 to -12?

You can buy SIP-packaged isolated DC-DC converters from Mouser or Digikey, ballpark $8, all done.

John

Thank you all for the answers and suggestions.

Thanks, that's what we were looking for.

We use it for isolation purpose.

It's +12V to +12V (no change in polarity).

One thing, what is the topology behind these SIP-packaged isolated DC- DC converters?

Still single ended primary inductor converter?

Regards

I'm guessing they are 2-transistor self-oscillating square wave forward converters.

We sometimes make our own isolated supplies from mosfet or opamp drivers and ISDN transformers.

John

I used one recently, 12V to 12V, to isolate something. I noticed that it needed 100uF on input and output to keep ripple / noise down to a reasonable level. That *was* mentioned in the datasheet, when I read it properly. Don't make the same oversight...