Sometimes you need a simple negative power supply. The best example is the contrast PSU for common small LCD device. Building -5V from a battery or a wallmart supply isn’t really easy. I decided to build a small device that is able to provide -5V, -12V, -15V. I used the MAX 764/765/766 serie. Simply change the chip to provide the good output.
Here the little schematic:
And here a pic, of the result:
As you can see, this stuff is damm small, use some common parts and can be reuse across different needs. Thanks Maxim for the sample :)
I used a 220uF instead of the 120uF one, and a small inductor but you can use a bigger one, if you need greater current.
what is advantage of using negative supply voltage?
Hum, this is usefull for a LCD contrast for example.
Low-power negative supplies are good for -Vcc for audio preamps or any other opamp circuit for that matter.
Did you also create a matching +15v power supply? If so, what did you use?
—Can a -12v be used in place of a -5v? I need to replace the power supply for my MS-9620 (K8N Master2-FAR) which requires a -5V and I have a power supply with -12V.
Can you please tell me which inductor you choose?
I’m searching for a small SMD(if possible) inductor.
The inductors described in the datasheet are relative big..