Controllable Power Supply Circuit for an Illumination System and Methods of Operation Thereof

摘要

A method for reducing acoustic noise produced during use of a lamp dimmer detects whether the dimmer is a leading edge ( 101 ) or a trailing edge dimmer ( 102 ). A nominal firing time of a leading edge dimmer is determined and a post-correction applied to a voltage applied to the dimmer starting from the nominal firing time so as to build-up the voltage gradually during a predetermined post-correction time period and thereby reduce the rate of rise of the leading edge thereof. A nominal cutoff time of a trailing edge dimmer is determined and a pre-correction applied to a voltage applied to the dimmer starting from the nominal cut-off time so as to diminish the voltage gradually during a predetermined pre-correction time period and thereby reduce the rate of rise of the leading edge thereof. Other methods are disclosed for soft starting filament lamps and controlling dimmer circuits.