A switched-mode power supply (SMPS) regulates output voltage by rapidly turning a switching element, like a MOSFET, on and off. This high-frequency operation allows the use of much smaller transformers and filter capacitors compared to linear supplies. They offer high efficiency and compact size, making them the standard choice for everything from computer power bricks to industrial motor drives.
The SMPS is whining under load, so check the output filter caps for high ESR.
The high-frequency switching in an SMPS makes it highly efficient but also a major source of electromagnetic interference (EMI) if not properly shielded.
Also heard as
- switched-mode power supply
- switching power supply
- switcher
Related terms
MOSFET
A metal-oxide-semiconductor field-effect transistor is a voltage-controlled switch used to amplify or switch electronic signals.
PWM
Pulse-width modulation is a technique for controlling average power delivery by rapidly switching a signal on and off.
PSU
A power supply unit converts utility AC power into the regulated DC voltages required by a system.
Power electronics
The branch of electrical engineering focused on the conversion and control of electric power.