+9V/0V/-9V DC power supply

[Cliff Schecht]

This is about the smallest solution I can think of at nearly 3:00 in the morning for going from 9V to -9V with decent regulation. It's Very simple in design and switches at about 100 kHz. Additional filtering could be added but probably isn't necessary. This has a pot onboard to adjust the output voltage for anything from -5V to probably -18V (ish) from a 9V input. I need to order some samples now and build some of these too.

The next little SMPS I want to build is an isolated 9V flyback supply with a SMD coupled inductor. I think I can make this have a similarly small footprint and hopefully not very tall (I expect the magnetics to be the tallest component).[/url]

[chief mushroom cloud]

nice...Mouser has the TIs for $ .72

[Cliff Schecht]

Or samples for free. Or crack open a cell phone car charger and steal the 33063 out of it .

[Cliff Schecht]

I pulled a 12V to 5V car adapter apart to steal the 33063 out of it (actually was a 34063 which is functionally equivalent) and built a quick 9V to -9V circuit. I also reused the inductor from the car adapter and built the rest with whatever I could scrounge together. Adjustment gets down to -22V!