Patent ID: 7332879

Claim:
A control device for controlling a power-converting module that is coupled to a light-emitting component, said control device comprising: a duration detecting unit adapted for comparing duration of a predetermined logic state of a pulsating input dim control signal with a reference time period; and a control signal generator coupled to said duration detecting unit and enabled by said duration detecting unit so as to generate a pulse-width-modulated control signal that corresponds to the pulsating input dim control signal and that is to be provided to the power-converting module, thereby enabling the power-converting module to generate drive voltage for driving the light-emitting component to generate a brightness output that corresponds to the pulsating input dim control signal, when said duration detecting unit determines the duration of the predetermined logic state of the pulsating input dim control signal to be not longer than the reference time period; said duration detecting unit disabling said control signal generator so as to disable the power-converting module and turn off the light-emitting component when said duration detecting unit determines the duration of the predetermined logic state of the pulsating input dim control signal to be longer than the reference time period; and a signal-filtering unit for generating a modulator control signal that corresponds to a reference voltage amplified by a gain equal to an average value of the pulsating input dim control signal, said control signal generator being coupled to said signal-filtering unit and generating the pulse-width-modulated control signal from the modulator control signal.