High-frequency DC power supply is a power supply that uses high-frequency transformers to achieve voltage conversion and rectification. Its working principle includes the following steps:

1. Input AC power: First, the input AC power is stepped down or stepped up by the transformer to obtain a suitable voltage to supply the subsequent circuit.
2. High-frequency conversion: The AC voltage is converted into high-frequency AC voltage through a high-frequency transformer.
3. Rectification: The high-frequency AC voltage is converted into DC voltage through a rectifier circuit (usually a rectifier bridge).
4. Filtering: In order to reduce the pulsation at the output end, a filter circuit is usually used to smooth the DC voltage.
5. Control circuit: The size and stability of the output DC voltage are adjusted through the control circuit to meet the needs of different loads.
6. Output: Finally, the processed DC voltage is output to the load for use.

Through high-frequency technology, the size and weight can be reduced, the efficiency can be improved, and the power supply can be directly supplied to high-frequency devices such as digital circuits. But at the same time, more complex control circuits and protection circuits are also required to ensure the stability and safety of the power supply.