| 摘要 |
<p>A resonant converter which may be employed as an electronic ballast for a gas discharge lamp, the converter being in the form of a full or half bridge circuit which includes at least a pair of power switches such as MOSFETs. The gates of the switches are actuated by substantially square wave cyclic gating signals having complementary duty cycle ratios and a frequency somewhat above a resonant frequency of the converter circuit. The energy supply to the lamp is variable in accordance with the duty cycle ratios of the gating signals. In order to avoid generation of high voltage and current transients in the converter when a change in operating state requiring a substantial change in duty cycle ratios of the gating signals is to be performed, as when effecting turn-on or turn-off of the lamp, the changes in the duty cycle ratio are ramped to occur incrementally over several cycles of the gating signals rather than directly to required final values of the duty cycle ratios.</p> |
