Abstract: A method and apparatus for controlling gain factor in a driver device for a lighting device according to the input voltage signal to reduce output current or output power dependency on the amplitude of the input voltage signal. One method couples an input voltage signal to the input port of the driver device and couples an output branch to the output port of the driver device. The gain factor is adjusted according to the input voltage signal to reduce output current or output power dependency on input voltage amplitude of the input voltage signal. The gain factor can also be configured according to a reference voltage and the output voltage across the output port to deliver a substantially constant output power.

Abstract: Methods and apparati for controlling bleed current (IBLEED) in a driver circuit (20) for a lighting device (23). A method embodiment of the present invention comprises the steps of coupling a dimmer (21) to an input of the driver circuit (20), and forcing the bleed current (IBLEED) to be inversely proportional to the time-averaged voltage (VLEDP) at said lighting device (23). The dimmer (21) consumes power even when the lighting device (23) is not emitting light.

Abstract: Methods and apparati for forcing the current through a load (11) in a variable DC electrical circuit to be proportional to the input voltage (V(in)). A circuit embodiment of the present invention comprises a source (27) of input AC; a rectifier (23) coupled to the input AC source (27), said rectifier (23) producing a variable DC input voltage; coupled to the rectifier (23), a load (11) having a variable direct current flowing therethrough; and means (12-16) for forcing the current through the load (11) to be proportional to the variable DC input voltage.