Patent ID: 8159145
Filing Date: 2012-04-17
Classification: H05B

Abstract:
1. A synchronous operating system for a plurality of discharge tube lighting apparatuses each converting a direct current into a positive-negative symmetrical alternating current, oscillator capacitors of the plurality of discharge tube lighting apparatuses being commonly connected, AC power from the plurality of discharge tube lighting apparatuses being supplied to a plurality of discharge tubes, each of the plurality of discharge tube lighting apparatuses comprising: a resonant circuit including a capacitor connected to at least one of primary and secondary windings of a transformer, an output thereof being connected to the discharge tube; a plurality of switching elements of bridge configuration connected to both ends of a DC power source, to pass a current through the primary winding of the transformer and the capacitor; an oscillator generating a triangular wave signal whose inclination for charging the oscillator capacitor and inclination for discharging the same are the same and which is used to turn on/off the plurality of switching elements; a first signal generation part generating a first drive signal having a pulse width corresponding to a current passing through the discharge tube, in a period shorter than a half period of the triangular wave signal, configured to drive a first group of one or more switching elements among the plurality of switching elements and pass a current through the discharge tube; and a second signal generation part generating a second drive signal having a pulse width substantially equal to that of the first drive signal and a phase difference of about 180 degrees with respect to the first drive signal, configured to drive a second group of one or more switching elements among the plurality of switching elements and pass a current through the discharge tube in a direction opposite to the current passed by the first drive signal.