| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a lamp abnormality detection device, having cost reduced in detecting abnormality, in relation to an inverter type lamp device where inverters having various ratings are used. SOLUTION: A fluorescent lamp Lp is lit by the control of a half-bridge inverter Iv. The lamp current is detected by a bidirectional photocoupler PC of this lamp abnormality detection device Dt and converted into a voltage. A microcomputer MC samples the voltage for 100 ms at an interval of 1 ms. The number of abnormality detection times A, that is, the frequeug of the occurrence of abnormal voltages exceeding a reference voltage are detected in this period is counted. A sensitivity set value Q is previously stored in the microcomputer MC, and when A becomes equal to or more than Q by comparing A with Q, it is determined as being abnormal and reported with a display or an alarm. Since the sensitivity set value Q is appropriately set by considering the use environment of the fluorescent lamp, the single lamp abnormality detection device can be applied to the inverters having various ratings.</p> |
