| 摘要 |
PROBLEM TO BE SOLVED: To provide an abnormality detecting device for a discharge lamp driving device that securely detects the abnormality of the driving device even if the discharge lamp is driven by a duty dimming method. SOLUTION: A current flowing through a xenon lamp 18 driven by the duty dimming method by the driving device 4 is detected by a resistor 5. A resulting voltage generated across the resistor 5 is rectified and shaped into a sawtooth wave by a waveform shaping means 19 comprising diodes 6 and 7 and a capacitor 12. Rectangular wave signals are outputted by switching on and off a transistor 15 based on the shaped voltage. Then, the abnormality is detected by observing the output state of the rectangular wave signals by an abnormality determination part 17a of a control unit 17. COPYRIGHT: (C)2005,JPO&NCIPI |
