| 摘要 |
<p>A trouble detecting circuit includes (a) a loop circuit conducting a loop current to two discharge tube lamps (L1, L2) in a normal state, in which the two discharge tube lamps are driven with two alternating driving voltages having phases reverse to each other by one or two secondary side windings of one or two transformers (Tp, Tn), and (b) a monitoring circuit monitoring a voltage between two points which are at a substantially same potential in a normal state in the loop circuit.</p> |
