A switched-mode power supply (SMPS) is a type of power supply that uses switching devices, such as transistors or MOSFETs, to convert electrical power efficiently from one form to another. SMPSs are widely used in electronic devices, ranging from consumer electronics like computers and televisions to industrial applications like industrial machinery and telecommunications equipment.

The key features and components of an SMPS include:

1. Switching Devices: SMPSs typically use semiconductor devices like transistors or MOSFETs as switches. These switches rapidly turn on and off to control the flow of electrical energy through the power supply.

2. Transformer: SMPSs often incorporate a transformer to step up or step down the voltage level as required by the application. The transformer operates at high frequencies, allowing for smaller size and weight compared to traditional transformers used in linear power supplies.

3. Rectifier and Filter: The output of the transformer is rectified to convert it from alternating current (AC) to direct current (DC). A filter circuit is then used to smooth out the DC voltage and reduce ripple.

4. Switching Controller: The switching controller, typically implemented with an integrated circuit (IC), regulates the switching of the semiconductor devices based on feedback from the output voltage or current. This allows the SMPS to maintain a stable output voltage or current even with varying input conditions or load changes.

5. Feedback and Control Loop: SMPSs often incorporate a feedback loop to continuously monitor the output voltage or current and adjust the switching frequency or duty cycle of the switching devices to maintain the desired output characteristics.

6. Protection Circuitry: SMPSs may include protection features such as overvoltage protection, overcurrent protection, and thermal shutdown to safeguard the power supply and connected devices from damage due to fault conditions.

SMPSs offer several advantages over traditional linear power supplies, including higher efficiency, smaller size, lighter weight, and better regulation of output voltage or current. These characteristics make SMPSs well-suited for applications where space, weight, and energy efficiency are important considerations.

Overall, switched-mode power supplies play a crucial role in modern electronics by efficiently converting electrical power to meet the diverse needs of various electronic devices and applications.