| 摘要 |
a high-frequency inverter circuit (2) for controlling a pair of MOS FET to alternately turn ON and OFF and converting voltage of a DC power source (1) to high-frequency voltage; a resonance load circuit having an inductor (6), a capacitor (8), and a discharge lamp (7) which are supplied with the high-frequency voltage from the inverter circuit and having an argument set between -20 deg and 40 deg for the lighting frequency fs in the impedance when the discharge lamp performs rated operation; and a CPU (13) for continuously generating a pulse voltage for driving the MOS FET (3, 4) ON and OFF with a shorter cycle than the lighting cycle of the discharge lamp (7) according to program data and the data stored in a memory (18) and performing pulse-width modulation control of the ON-width of the pulse voltage according to the waveform change of the sinusoidal wave voltage corresponding to the lighting cycle. Substantially sinusoidal wave current is supplied to the discharge lamp (7) from the high-frequency output from the inverter circuit (2).
|
