These step-up/step-down regulators take an input voltage from 3 V to 30 V and increase or decrease it as necessary to produce a fixed 5V, 6V, 9V, 12V or 24V output, depending on the version. They are switching regulators (also called switched-mode power supplies (SMPS) or DC-to-DC converters) with a single-ended primary-inductor converter (SEPIC) topology, and they have a typical efficiency between 80% and 90%. The available output current is a function of the input voltage, output voltage, and efficiency (see the Typical Efficiency and Output Current section below), but it will be around 2 A when the input voltage is close to the output voltage.