Switch mode power supply (SMPS) transformers are a highly efficient form of transformer, used in devices like personal computers.
A switch mode power supply is an electronic power supply that incorporates a switching regulator to efficiently convert electrical power. Like other power supplies, an SMPS transfers power from a DC or AC source (which is often mains power) to DC loads, such as a personal computer, while converting voltage and current characteristics.
Any switched-mode power supply that gets its power from an AC power line (also known as an 'off-line' converter) requires a transformer for galvanic isolation, which prevents current flow. Some DC-to-DC converters may also include a transformer.
SMPS transformers run at high frequency. Most of the cost savings (as well as space savings) in off-line power supplies result from the smaller size of the high-frequency transformer.
SMPS transformers have many different applications. They can be used as broadband transformers, DC-to-DC converters, low-power DC-to-DC converters, pulse transformers and power sourcing equipment, among other uses.