Charge pumps are DC to DC converters that are often needed in designs requiring more than one dc supply voltage. Its made up of switches and capacitors. The switches are usually diodes in discrete designs but are also MOSFETs in IC versions. The capacitors are electrolytic or ceramics depending on the switching speed. Theres no need for an inductor. Charge pumps can double, triple, halve voltages but they can also invert or scale voltages. They are commonly used in low-power electronic devices to suit a voltage for different parts of the circuit.
Charge Pumps have a few advantages over the majority of other types of DC-DC converters and they are:
Simplicity in build
Lower cost of production
Higher efficiency than linear