Looks like the main power hog in your circuit is the relay.
Why not use a Solid state Relay or better yet build one
using MOC3041 Triac Opto Coupler and A good old Triac ?
An added benifit of this circuit is that MOC3041 gives you
Switchover at Zero Crossing. Of course, I'm assuming that
You want to switch AC mains. If not, forget this Idea.
I've had the same problem with a PIC16f84A. And I'm using MOC3041

Reagrds,

Jeethu Rao

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Alexandre Domingos F. Souza
> Sent: Thursday, July 26, 2001 6:23 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Transformerless PSU
>
>
>         Dear guys,
>
>         I think it's a basic one, but maybe fits the list
>
>         I designed a circuit with a PIC (12C508) that turns on
> and off a relay, controlled by an external source. The power to
> this circuit (around 120mA) is a small transformer. I'd like to
> build a transformerless PSU into this circuit. But EVERY scheme I
> found on the internet was unusable. I saw something on the
> Embeeded Control Handbook from Microchip, but it only goes to (if
> I'm not mistaken) 45 mA. Maybe someone can help me to develop (or
> at least learn to) a simple transformerless PSU that can give me
> 12vcc / 120 mA???
>
>         Thanks for any info! :o)
>
>
> ---8<---Corte aqui---8<----
>
> Alexandre Souza
> taito@terra.com.br
> http://planeta.terra.com.br/lazer/pinball/
>
> ---8<---Corte aqui---8<----
>
> --
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>

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