TL;DR I guess. I thought he said 3V in and 5V out.Tom,
Didn't you mean to start a new thread with those circuits?
I have to wonder that, because they certainly don't meet spinnakers' requirements very well:
There's no enable/disable input.
It has no provisions to regulate the output current.
The output current is roughly 1/2 what is required.
70% is really not all that efficient.
Sure, it may be possible to fix all of that stuff - but we'd be reinventing the wheel here.
And yes, the current is limited; but not adjustable. If you put an LED on the output, it will give you about 80mArms in pulses around 1 MHz. This is because the transistor will stop oscillating if the LC tank does not get enough energy.
When driving an LED the efficiency is about 72%. This could be improved, but I'm not sure how.
Maybe an MC33063? No enable pin, but operates from 3V to 40V with output 3V to 40V.