Jinx wrote:

> Anything static in series is going to waste power through heating.

While this is true, ...

> 5 diodes will have to pass at least the same current as the load

... this isn't necessarily: with a step-down switcher, the load current is
higher than the input current, so the current through those diodes would be
much lower than the current through the load LEDs. (But whatever current
there is, the energy is still wasted. Designing a switcher that works up to
the required 30something V is probably the best solution.)

Gerhard

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist