ELECTRONIC DIMMING BALLAST FOR COMPACT FLUORESCENT LAMPS

摘要

The operating frequency of a ballast is sufficiently far from resonance of a resonant tank circuit (430) that, when a compact fluorescent lamp (500) is dimmed to about one percent light output level, the ballast is operating with an open loop gain below a predetermined level, and is operating with an output impedance greater than a predetermined and more preferably, greater than twice the absolute value of the maximum negative incremental impedance of the lamp. By changing the frequency to 85 kHz from 80 kHz through control circuit (418), for example, the gain is maintained about the same whether the light output is at five percent or one percent, for example.