5V from mains

Web search "off line switcher". Or "smoke".

martin.shoebridge wrote: : Can anyone point me in the right direction ? I saw a chip that does this a : long time ago, but can't remember what/where... : TIA AFAIR the 5V were not isolated from the mains. Perhaps thats not what you want.

Does it have to be a chip? They make 5V switching wall warts now that are so small they fit inside the mains plug, you can't even really call it a "wart" any more.

Harris semiconductor did the chip that he probably saw, but I don't think Intersil now do it, it seemed to disappear a while ago. These are ideal for specific things, such as powering logic circuits inside mains equipment, where insulation/isolation is provided elsewhere. However for any application where this is not the case, the minature wall wart approach is a lot safer. It also simplifies getting approvals, so unless the production 'run' is large, may well be the better solution. For a non isolated supply, inside a piece of equipment, the PowerIntegrations LNK304, is the current popular choice. It is used inside many things like lamp dimmer assemblies.

Best Wishes