Charge pump is an electronic circuit that uses capacitors as energy storage elements to create either a higher or lower voltage power source. This circuit is capable of high efficiencies, sometimes as high as 90-95% while being electrically simple circuits. This pump uses some form of switching device, which controls the connection of voltages to the capacitor. It has two stages to generate a high voltage. In the first stage, the capacitor is connected across a voltage and charged up. Then in the second stage, the capacitor is disconnected from the original charging voltage and reconnected with its negative terminal to the original positive charging voltage. It operates at tens of kilohertz to minimize the amount of capacitance required. This charge pump is used in RS-232 level shifter that is used to derive positive and negative voltages from a single 5 V or 3 V power supply rail. It is also used as LCD or white LED drivers.