DD> The three ICs you suggest use different frequencies. What is
DD> the advantage of going to the faster (or slower) frequencys? 

 Higher freq, smaller coil. 

 Why don't you just buy a 6V battery? And trickle charge it off your
12V system with a 12V/5W light bulb?

 Like Brenton, I can do the sums and I'm probalby stupid enough to
actually build my own SMPS, but anyone with half a brain looks for the
lazy way. Lazy is best, and it always works. Sometimes, you even
finish the project.

Regards,
Bob

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