Here is the situation, I have a 4v 1500mah lithium ion battery that needs a kick in the butt. I intend to power a variable voltage regulator with this battery but I first need to make a tiny & efficient voltage doubler or something along those lines to satisfy the voltage regulators needs, the variable voltage regulator is already made and has an adjustment range from 2v to 8v and with the battery alone won't perform above 4.5v. The problem is that after hours of web searching I can't find anything that will convert my 4 volts input into a min 7 volts, max 9 volts output. Basically I need to double the power output of my battery while keeping it tiny and inexpensive. A little more info, this unit will not be constantly in the on position it will only be on for 3 to 10 seconds at a time and requires a fast (instant) power up, it will be under loads of 1.5ohm to 5ohm depending on my selected voltage output setting on the regulator, & the case and battery are pretty well set in stone as the project is nearly complete aside from the input voltage situation. If anybody can help me with this situation in the form of general know how, schematics &/or a parts list it would be greatly appreciated...