12V and 9V isolated power supply

[djc]

Hi

I want to build an isolated power supply. Input will be 12v DC and output is 12V and 9V but isolated. How to do that? If smps is used, which switcher should be used?. I don't have any experience with SMPS and power supply, however want to build one as soon as possible. Can anybody please guide.

 

[smijesh]

You should use SMPS with transformer. Transformer will take care of isolation. You did not say about the current requirements?.
You can use push pull DC to DC converter with SG3525 IC or other IC

**broken link removed**

 

[djc]

Thank you smijesh,

Current requirement is about 2Amps. It's being used for telephone circuit where AC voltage is required for ringing circuit. Anything else u required to know. The Post Page doesn't exists now.

 

[schmitt trigger]

An 18 watt supply is well within the capabilities of the simplest isolated topology, the flyback.

 

[mtwieg]

Well there are off the shelf power modules that fit your specifications, but they are a lot more expensive than a DIY circuit. A multi output flyback would be the simplest solution, if cross regulation is not a big problem.

 

[djc]

Thanx guys,

Do anybody has some schematics.