| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC/DC converter that determines a failure of a power supply unit when a current detection voltage obtained by detecting an output current of a DC/DC converter is below a rated voltage except the case of drooping. SOLUTION: The DC/DC converter includes: an output-low-voltage detection circuit 30 for detecting a low voltage by comparing an output voltage with a reference voltage whose threshold is lower than that of a rated voltage; an output-constant-voltage control circuit 10 for comparing the output voltage with the rated voltage so as to control them; a drooping control circuit 20 for drooping the output voltage by narrowing an ON-width of a switching element when a current-detection voltage, obtained by detecting an output current, exceeds a drooping reference voltage; an output-voltage-drop detection circuit 40 for determining that it is normal when the output-constant-voltage control circuit determines that it is drooping even though the output voltage is below the rated voltage; and a latch stop circuit 50 for stopping the switching element by determining that it is a failure when the output voltage is below the reference voltage of the output-low-voltage detection circuit or when the output-voltage-drop detection circuit determines that it is not normal. COPYRIGHT: (C)2010,JPO&INPIT
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