| 摘要 |
<p>A discharge lamp lighting apparatus comprises a bridge type rectifying/converting circuit (CR1); feedback circuits (FB1,FB2); a chopper circuit (CR2); a charging circuit (CR3); a resonant circuit (CR4) that resonates with a high frequency signal to light, with a resonance voltage, a discharge lamp (DL) connected to an output terminal of the resonant circuit (CR4); an inverter circuit (CR5) that converts a DC power, which is charged into the charging circuit by an alternately switching operation of a pair of switching elements (Q1,Q2), to a high frequency AC power; and a switching means (SW) that is connected between a junction (J3) of capacitors (C1,C2) of the charging circuit and a junction (J2) of a pair of rectifying elements (D1,D2). It is arranged that the switching elements be shared by the step-up chopper circuit and the inverter circuit and their duties be varied within a predetermined range, thereby coping with various variations of the power supply voltage.</p> |
