Mark Rages wrote:
>> I haven't picked my LED's yet, but I know their Vf will be less than 3 V.
>>     
>
> How are you planning on regulating their current?

Not sure if this is a trick question... but current-limiting resistors.

If the Vf is 2.2 volts and if I want 20 mA, then:

    3 - 2.2 volts = .8 volt

Then I just figure out what value resistor has .8 volt across it when 
there's 20 mA thru it:

    R = V divided by I =     .8 divided by .02     =     40 ohms

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