| 摘要 |
PURPOSE:To bring the power supplied to a lamp close to constant current property by comparing the output of an inverter with a plurality of reference voltages, and adding the output geared to the comparison result to the detection output of the current flowing to a switching element so as to control the switching of the inverter. CONSTITUTION:The output voltage and the DC input current of an inverter 10 are detected with a voltage detector 30 and a current detector 25, respectively. The error voltages between this detected voltage and those of reference voltage sources 43 and 53 for setting output are amplified with error amplifiers 40 and 50. Moreover, the detected voltage is compared with that of a reference power source 62 for detection of no load, and the output at no load is outputted from a voltage limiter 60. And, the output of devices 40 and 50 and the limiter 60 is added to the detection output of the detector 25 through an OR circuit 60, and the switching of the inverter 10 is controlled by feedback through a high frequency adjuster 82, thus by simple constitution, the power supplied to a lamp can be approximated to constant voltage property. As a result, a discharge lamp can be lit stably without change on standing in illumination, preventing the breakdown of discharge lamp. |
