| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply device that has small dependency of overcurrent protection on an input voltage and can be made compact.SOLUTION: A switching power supply device includes: a transformer; a switching element which alternates application and non-application of a voltage to primary winding of the transformer; a drive part which drives the switching element; a current detection part which detects a current flowing to the switching element; and an overcurrent determination part which determines whether the current detected by the current detection part is an overcurrent. When the overcurrent determination part determines an overcurrent, the operation of the drive part is limited. The overcurrent determination part has a compensation part which compensates for an influence of a response delay of overcurrent protection, and utilizes a voltage which depends upon an input voltage to the switching power supply device and is induced across auxiliary winding of the transformer. |
