There were recent in-depth discussions on this subject:
Good info guys thanks. I somehow missed those posts.
Pavloven, So if I am reading your diagram correct you just replaced the D1 diode with an led and it dropped the supply voltage to the main board from 5v to 3.3v. Very nice solution!!! I think I will use that one.
Could red LED be replaced with some stabilitron to avoid light pollution and to increase current load?
This diode is installed in series with the chip and part of the supply voltage drops on it.
You can use:
-3 silicon diodes connected in series (1N4148)
- Zener diodes for a voltage of about 1.8 V (for example 1N4615-1, DDZ9678-7, TZS4678, SZMMSZ4678T1G)
The maximum forward current is indicated in the DS and is limited by the power dissipated by the diode (100-500mW)