Re: [avr-chat] high speed LED switching circuit

[Daniel O'Connor]

On Thu, 30 Jun 2005 08:54, Reza Naima wrote:
> I'm looking at building a circuit to drive an IR LED at a pretty fast
> speed to transmit data (~5Mhz).  I tried a simple circuit that used a
> transistor to switch the LED on and off, but it seemed fairly slow.  I'm
> looking at having about 60mW of power (~20mA @ 3v) to drive it.  Any
> suggestions on a high speed switching circuit?

Perhaps you should look at an IRDA LED driver circuit since they have to drive 
LEDs and that sort of rate?

This might help too
http://www.fiber-optics.info/articles/LEDs.htm
especially the 3rd digital drive example they give.

A guy at work did some tests trying to get an LED to carry RF signals for a 
receiver and he got them up to 20-30Mhz (very low levels though). He reckons 
lots of current is the key :)

-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
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