SWITCHING POWER SUPPLY DEVICE

摘要

PROBLEM TO BE SOLVED: To allow a user to freely set a level for detecting an overvoltage and freely select even a withstanding voltage of an external component in a DC power supply device.

SOLUTION: The switching power supply device has a control circuit which on/off-controls a switching element for supplying a current intermittently to an inductor. The switching power supply device includes: an abnormal voltage detection circuit (13) which detects that an output voltage has reached a predetermined potential or decreased below the predetermined potential by comparing the output voltage with a predetermined voltage; a variable voltage source (17) which generates the predetermined voltage; and a control terminal (P1) for setting a voltage to be externally applied to the abnormal voltage detection circuit from the external variable voltage source. When the abnormal voltage detection circuit detects an abnormal voltage, the control circuit changes the on/off-control of the switching element (SW1).

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