DISCHARGE TUBE LIGHTING DEVICE

摘要

An inverter control circuit (25) subjects transistors (Q1), (Q2) of a drive circuit (21) to complementary on/off operation.  The inverter control circuit (25) generates a rectangular wave signal S1 of an on/off frequency (a first frequency f1) of the transistors (Q1), (Q2) by self-oscillation.  A triangular wave generation circuit (12b) in a light-control signal generation circuit (10) generates a triangular wave signal of a second frequency f2 for making driving by the first frequency f1 intermittent.  A comparator (12d) compares an output voltage of a light-control voltage generation circuit (11) with an output signal of the triangular wave generation circuit (12b) and generates a rectangular wave signal S2 PWN-modulated according to a light-control voltage.  A rectangular wave generation circuit (12c) generates a rectangular wave signal S3 so as to attain auxiliary intermittent driving by a third frequency f3 lower than the first frequency f1 and higher than the second frequency f2.