A switching power supply generally consists of four main components: the main circuit, the control circuit, the detection circuit, and the auxiliary power supply.
1. Main Circuit
Inrush Current Limiting: Limits the surge current on the input side at the instant the power supply is switched on.
Input Filter: Its function is to filter out noise present in the power grid and to prevent noise generated by the unit itself from feeding back into the grid.
Rectification and Filtering: Directly rectifies the AC power from the grid into relatively smooth DC power.
Inversion: Converts the rectified DC power into high-frequency AC power; this constitutes the core component of a high-frequency switching power supply.
Output Rectification and Filtering: Provides a stable and reliable DC power supply in accordance with the requirements of the load.
2. Control Circuit
On one hand, it samples the output signal, compares it against a preset reference value, and subsequently controls the inverter-modifying its pulse width or pulse frequency-to ensure output stability. On the other hand, based on data provided by the detection circuit and processed by the protection circuit, it enables the control circuit to implement various protective measures for the power supply.
3. Detection Circuit
Provides the protection circuit with real-time data regarding various operating parameters and instrumentation readings.
4. Auxiliary Power Supply
Enables software-based (remote) startup of the power supply and provides operating power for the protection circuit and the control circuit (including components such as PWM chips).
