What is Power Supply?
A power supply is an electrical device that supplies electric power to an electrical load
Step 1: Power Supply How to Work?
when the AC voltage connected to the power supply the AC mains input is directly rectified and then filtered to obtain a DC voltage. The resulting DC voltage is then switched on and off at a high frequency by electronic switching circuitry, thus producing an AC current that will pass through a high-frequency transformer. switching occurs at a very high frequency (typically 100 kHz — 1 MHz),
thereby enabling the use of transformers and filter capacitors that are much smaller, lighter, and less expensive than those found in linear power supplies operating at mains frequency. After the inductor or transformer secondary, the high-frequency AC is rectified and filtered to produce the DC output voltage. If the SMPS uses an adequately insulated high-frequency transformer, the output will be electrically isolated from the mains; this feature is often essential for safety.
Switched-mode power supplies are usually regulated, and to keep the output voltage constant, the power supply employs a feedback controller that monitors current drawn by the load. The switching duty cycle increases as power output requirements increase
Step 2: Output Voltage
the output voltage power supply always remains constant, when the input voltage is decreased the output voltage is decreasing too, the optocoupler send a feedback to the IC and the IC increase the voltage(on the gate pin of the power MOSFET), then the output voltage decreased again , this operation is very fast so the output voltage always remains constant