Voltage Doubler Test

 

I decided to do some tests on the voltage doubler kit to see how it compared to the stock circuit from a datasheet.

 

I made two voltage doublers using the AMZ pc boards. One was the circuit that I sell in the kit and the other was a standard doubler from the TC1044S datasheet. Under no load, both circuits produced just under 18v output but the voltage drops as you put a load on the charge pump output.

I used two LEDs, each with a current limiting resistor, for a total load of 28 ma, which is a typical load for a couple of average pedals that the doubler would be required to power. With 9.0 volts driving the boards from the bench power supply, the AMZ doubler produced 16.06v and the TC1044S produced 16.18v. This is very close and the slight difference could be due to the fact that different diodes were used on each pcb.

 

The main advantage was revealed when I looked at the output of the doublers using an oscilloscope to get an idea of the voltage ripple.

 

The AMZ had 0.14v ripple riding on the DC voltage while the TC1044S had 0.25v ripple. This is a significant difference. Futhermore, the AMZ ripple was a smooth (almost) triangle wave while that from the TC1044S was a sharp angular wave, much like a square wave with a sawtooth tail on it.

 

Not only is the ripple from the AMZ circuit less, but there are fewer high harmonics in the tri wave than will be present in the sharp ripple wave of the TC1044S, and thereby less noise in your circuit.