| 摘要 |
PROBLEM TO BE SOLVED: To operate a voltage boosting circuit preferably even if a feedback loop route is abnormal in a light-emitting device drive circuit. SOLUTION: The light-emitting device driving circuit includes a voltage boosting circuit for supplying a drive boosting voltage to the light-emitting device, a current circuit for driving the light-emitting device by a current, an ordinary feedback loop route for inputting a voltage of the light-emitting device to the voltage boosting circuit as a feedback voltage, a preliminary feedback loop route for inputting the voltage of the light-emitting device to the voltage boosting circuit as the feedback voltage, an abnormality detecting circuit for comparing the feedback voltage inputted into the voltage boosting circuit part by the ordinary feedback loop route with a preset determination voltage to detect an abnormality, and a switching circuit for switching a route from the ordinary feedback loop route to the preliminary feedback loop route when the abnormality detecting circuit detects the abnormality. COPYRIGHT: (C)2011,JPO&INPIT
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