A step-down converter, also sometimes called a buck converter, is a DC-to-DC power converter which steps down voltage from its input side to its output side.

A stepdown converter is a class of switched-mode power supply or SMPS that usually contains at least two semiconductors to do the conversion although some step down converters replace the diode with a second transistor used for synchronous rectification and at least one energy storage element, a capacitor, inductor, or the two in combination.

To reduce voltage ripple, filters made of capacitors sometimes in combination with inductors are added to the converter's output side and input side filter.

Worktruck Outfitters supplies stepdown converters from top manufacturers including SEC America and Thor Power Products.