Hi all,

I need to supply power to a large number of LED's in a vehicle, where all 
LED's will be on or off simultaneously, and with 2 brightness levels.  I also 
want to use a constant-current source for this.  With the matrix I'm planning 
to use for the LEDs (14 parallel strings of 6 series LEDs each), my initial 
high-level calcs are ~210mA normal and 350mA when the brakes are pressed.

To keep the whole thing relatively small and low-cost, the good old generic 
LM317 comes to mind, but the question is how to set up a single LM317 for 
dual current levels.  I came up with this circuit, though I'm not sure if it 
would work properly...
	http://www.narwani.org/neil/electronics/Const-2Cur-Ckt.gif

Any ideas?  Is there a better way to achieve this?


Cheers,
-Neil.


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