[En-Nut-Discussion] using internal power supply for other circuits

[Lyle Giese]

scostas wrote:

>Hi all:
>
>I want to control some LEDs and optocouplers from the Ethernut, but
>Idon't want  to overcharge the internal 3.3 regulator. What is the
>maximum charge I can add to it? I don't want to use an external power
>supply for this (only for the circuits controled by the optocouplers).
>
>Another question: is safe to control the optocouplers and LEDs directly
>from the outputs, or is better to use a transistor in the middle to
>avoid an excesive current in the ports?
>
>Thanks.
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>  
>
I built a project around some hi-output LED's.  I tapped into the 9 vdc 
supply pins, ran that through a 7805 and then used some 74ls05's to 
drive the LED's from the dataport outputs.

But then I was using hi-output LED's for max light(2 lite up at a time) 
and they run more current than what I felt was safe for data 
outputs(~20mA each).  I just made sure I had enough output on the power 
pack feeding the board to do both.