I'm trying to set up an attiny2313 to drive an array of LEDs and blink them in different patterns. Rather than putting a series resistor in line with each LED (they'll be controlled separately, so I can't do tricks like putting them in series with each other), I was wondering about just using a couple diodes to get the voltage down to the right range.
The system is running at 3.3V (with a regulator to keep it pretty constant), and two 1N4001 diodes will drop that down to 1.9V - right in line with the lower end of the 1.8 - 2.2V these LEDs are specced for. Since the diodes will always want to maintain the same voltage drop across themselves, I don't have to worry about that voltage changing as I turn the LEDs on or off. Overall I save 6 components.
Has anyone else tried something like this? Is there anything I've overlooked? I realize the diodes will have to dissipate the full current from all the LEDs, but for this small amount of current that doesn't seem like it will be an issue.
It seems to me like it could work. I’d say at least try it out. It looks like a nice way to keep down component count.
If I understand what you want to do correctly, a current limiter won’t be as nice as you’ll need one per LED. Otherwise, the regulator will try to maintain constant current over your entire array. Turn on more LEDs and they all dim, turn a single one on and it will get full current… you get the idea.
Out of curiosity, how many LEDs are we talking about? How are they wired?
Hello~everyone,it's my pleasure to be here.I have got into troubles! I need you help!
I have made a circuit about LM339 ,(this site)but the output is odd! Here you can see ,the white triangular wave is input, the green wave is compare wave while the red wave is belong to output.Anyone could tell me why?
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