| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize a power supply unit and save energy. SOLUTION: This power supply unit include a transformer, a first switching device, and a switching control circuit, wherein a primary winding of the transformer is connected to a DC power source, a first rectifying device, a first smoothing circuit, and a first output terminal sequentially connected to the secondary winding of the transformer, wherein the voltage of the first output terminal is detected and fed back to the primary side to suppress the first switching element, and a second rectifying device, a second switching element, a second smoothing circuit, and a second output terminal to the secondary winding or the other winding. The voltage after the second switching device output is inputted to a timing circuit through an error detecting circuit, and a pulse is generated after the first switching device obtained from the winding voltage of the transformer to an edge detecting circuit starts continuity to reset the timing circuit. The wave of the timing circuit output is shaped to suppress the second switching device with a drive circuit.
|
