What term is sometimes used to refer to switching power supplies?

Switching power supplies are commonly referred to as DC to DC converters, which is the correct answer. These power supplies operate by converting a direct current (DC) input voltage to a different DC output voltage. This is achieved through the use of high-frequency switching techniques, which enhance the efficiency and size of the power supply. They can either step up (boost) or step down (buck) the voltage as required by the application, making them versatile and widely used in various electronic devices.

In contrast, other terms like AC to AC converters, DC to AC converters, and AC to DC converters refer to different types of power conversion processes. AC to AC converters typically change the frequency or voltage of alternating current (AC) power, while DC to AC converters, also known as inverters, convert DC back into AC. AC to DC converters, on the other hand, transform AC power into a DC format. Each of these processes serves distinct functions in power management and electronics, differing fundamentally from the operation of switching power supplies.