DC/DC converters

The term DC/DC converter or DC-DC converter usually refers to an electronic voltage converter designed to change the magnitude of DC voltage or current, generally for conversion between different DC power systems. Transistors and diodes are used for switching, inductors and capacitors are used as energy storage during conversion, and pulse transformers are used for galvanic isolation.
Basic design:
Charge pump - topology for very low power (current of the order of milliamps.) The advantage is the design without coils - it uses capacitors as energy storage.
Voltage Reducer - (step-down- or buck-converter)
Voltage booster - (step-up- or boost-converter)
Inverter - allows both voltage step-up and step-down, reverses the polarity of the voltage. (It has nothing to do with the so-called welding inverter, which is a popular and incorrect term for an electronic welding power supply, which is usually implemented as a single-acting pass converter.)
Dispersionless inverter - the output voltage can be higher or lower than the input voltage, the polarity remains the same
Bidirectional inverter - allows voltage transfer in both directions, i.e. the output can function as input and vice versa. Use e.g. in controlling motors with regenerative braking.
Dispersionless inverter (Ćuk) - reverses the polarity of the input voltage