problem getting -5V or opamps

[kar2on]

Hi, I have a filter circuit that uses opamps, the problem is that opamps require -5V, my circuit is suppose to be part of a portable system, so I'll need to use a battery. I've used a charge pump to helo get me a -5V supply, but instead of giving me -Vin which would be equal to -5V it's giving me only -2V, which is too little. Anyone have an idea on how to get a proper -5V supply.

 

[IanP]

There are two easy options: get a charge pump with higher output current or build a voltage inverter by yourself ..

Here are examples on the latter option (build around 555 timer):
http://www.electronics-lab.com/projects/power/023/
**broken link removed**

Regards,
IanP

 

[buenos]

You can get ICs, whose work not correctly. Maybe it is your problem. At me, the maxim ICs don't work usually. I have used a tps60400 to get -5V in a project with OPAMP, and it worked well.