> >Hi,Thanks everybody.I did not imagine that audio problem is also
> >involved. I have to checkthis out.Rgdsramana
>
>    Audio it's not a problem. PWM frequency either !
>    At 100mA and 13V you may filter the PWM and
> use a nice and fine DC level. The greateast frequency is
> the smaller capacitor you need. Simple.

Not so simple.  You don't want to tie capacitors to the PWM output drivers.
That would cause large currents and excessive losses every time the
switching components (FETs usually) are switched.  You could do an LPF with
a resistor or inductor in series with the PWM drive output with a cap
accross the load.  However, the resistor scheme creates loss, and the right
inductor usually needs to be too large to be practical.  I'm not saying you
should never filter a PWM power output, just that it's definitely not
simple, and not something I would recommend as a starting design for someone
new to this sort of thing.


*****************************************************************
Olin Lathrop, embedded systems consultant in Devens Massachusetts
(978) 772-3129, olin@cognivis.com, http://www.cognivis.com

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.