A DC-to-DC converter is a device that accepts a DC input voltage and produces an altered DC output voltage. Typically the output produced is at a different voltage level than the input. In addition, DC-to-DC converters are used to provide noise isolation, power bus regulation, etc. Types include High Voltage, High Power Density and Low Noise DC/DC Converters.

They are needed because unlike AC, DC cannot simply be stepped up or down using a transformer. In many ways, a DC-DC converter is the DC equivalent of a transformer.