A method of controlling an electronic ballast, an electronic ballast and a lighting controller

摘要

A method of controlling an electronic ballast for a lighting circuit, the electronic ballast comprising at least one bleeder, for use with dimmer circuits, is disclosed which method comprises: in response to a mains supply being connected to the lighting circuit, determining whether a dimmer circuit is present in the lighting circuit; and in response to determining that a dimmer circuit is not present, disconnecting the bleeder from the lighting circuit at least until the mains supply is disconnected. The method may be operable during a start-up phase, and the determination as to whether a dimmer circuit is present stored at least until the mains supply is disconnected. The determination, of either a leading or trailing edge phase cut dimmer, may be made by looking for a deviation from the expected sine-wave voltage, either directly through a temporal or voltage deviation, or indirectly by examining the second differential of the voltage with respect to time. An electronic ballast configured to operate such a method, and a lighting controller incorporating such a ballast, are also disclosed.