Solid state lamp control

摘要

Intelligent control of a solid state lamp when coupled to a trailing edge phase cut dimmer switch is provided. On and off cycles of the lamp's power stage switch are enabled during a period when the energy in the bulk capacitor is at its highest levels. During this period a bleeder circuit does not have to be enabled, which results in a greater operational efficiency as compared with normal switching schemes for trailing edge dimmers.

主权项

1. A lamp for connection to an AC mains supply via a trailing edge phase cut dimmer switch and comprising:
an input stage comprising a capacitor; an output stage including a solid state light source; a power stage including a power switch for selectively coupling the power stage with the output stage; a bleeder circuit including a load and a bleeder switch for selectively coupling a load with the input stage; and a controller arranged to: enable on and off switching cycles of the power switch throughout the course of a period that starts at a point of an AC mains supply cycle corresponding to a first energy level of the capacitor, as determined by a regulation threshold and ends at a point when the phase cut dimmer switch disconnects the AC mains from the lamp corresponding to a second energy level of the capacitor that is lower than the first energy level, wherein the regulation threshold is determined by feedback from one or more previous AC half cycles.