| 摘要 |
<p>A ballast (10) for powering a lamp load (70) comprising one or more gas discharge lamps (72,74) includes an inverter (200), a resonant output circuit (400), and a control circuit (600). During operation of ballast (10), control circuit (600) monitors at least one voltage within one or more series resonant circuits of output circuit (400). When the monitored voltage reaches a specified level, control circuit (600) directs inverter (200) to maintain its operating frequency at a present value for a predetermined period of time, so as to allow output circuit (400) to provide a suitably high voltage for igniting the lamp(s). If the lamp(s) ignite within the predetermined period of time, control circuit (600) ceases controlling inverter (200) to maintain its operating frequency at the present value, so as to allow for normal operation of the lamp(s). Control circuit (600) also provides a lamp stabilization function, in which the inverter operating frequency is prevented from falling below a specified minimum value, and a protective function, in which inverter (200) is deactivated in response to failure of the lamp(s) to ignite within the predetermined period of time.</p> |
