| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a switching power supply capable of reducing an applied voltage and a rush current sufficient to achieve a small and thin device, to which a power source is mounted, restraining output voltage variation and a switching loss, reducing a capacitor capacitance, improving power supply efficiency, and having a harmonic suppression restraining function and an instantaneous interruption compensation function. <P>SOLUTION: The switching power supply has a power-factor improving function, and outputs an insulated direct current. The switching power supply controls a switching element located in a direction to block discharging of a primary smooth capacitor near a zero-cross of an input voltage and when a commercial alternating current is cut, and controls two switching elements for controlling a charging current by the switching element located between an output side of a tertiary coil and the primary smooth capacitor, and boosting and charging the capacitor, mutually exclusively. <P>COPYRIGHT: (C)2012,JPO&INPIT |
