Bernd Grunwald wrote:
>
> Is there any efficient and not too expensive way to generate the ~5V for
> the PIC and some other devices out of the 230V AC Voltage from the net? Using
 a
> 7805 and other linear regulators is IMHO much too inefficient ...

If you have more time than money to spare, then reverse engineering
cheap mass-produced consumer electronics like alarm-clock(radio's) might
be interesting. You get a reasonable power supply and a case - often
with buttons, sometimes even a display and maybe some other interesting
parts that spawn ideas for additional features to your design.

> I need about 2 - 150mA at 5V to drive my PIC 16c84 based IR-remote receiver
> that will run 24 hours a day ...
>
> I thought of switching regulators e.g. TOP210 but I don`t know where to get
 the
> transformer (TDR1) mentioned in the data sheet and the TOP210 itself, because
 I
> need only a few peaces for my project ...
>
> Does anyone know how efficient normal transformers (230V => e.g. 6V) with
 diode
> based rectifiers are? If it is high enough so that a DC/DC switching regulator
> like the LM2574-5.0 (only about 77% efficiency :-( ) could be used? This would
> be pretty easy, because the mentioned inductors are very easy to get ...

Why do you care so much about efficiency if you are going to feed it
from mains voltage anyway?


Joost