I had a customer request for a circuit to make an older 18 volt chorus pedal more pedalboard friendly.
So i whipped up a simple, useful circuit. 9vdc to 18vdc charge pump.
Using a LT1054IP IC, a few caps and 1n5819 Schottky diodes, this is designed to take 9 volts DC and step it up to the 18 Volts that the pedal wanted to see.
The Schottky diodes have a very low voltage drop, thus allowing the voltage to remain close to 18V even under load. 17.8 (You could also use 1n4148 without any issue, but the resulting output voltage would be a bit lower due to the forward voltage of the diode)