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Negative Voltage Generator

Circuits and Layouts

This circuit was originally created to power part of a security system that required a negative voltage source in order to function.

Circuit:

 

The circuit basically consists of two alternating charge pumps that supply a -5V regulator, during tests it was found that the circuit gave a efficiency of about 55 to 25% when loaded from 10 to 30mA as below:

This load also dragged the supplied negative voltage down (below) which meant a conventional -5V regulator with a drop-out voltage of about 1.1 V would cease to function properly when a load of >17mA was demanded from the circuit.

Stripboard:

As Built: