Light emitting system with light emitting power stabilization

A power control device adapted to be connected electrically to a solid-state light emitting component that has an anode and a cathode, one of which is disposed to receive an input voltage, and that has a forward voltage with a magnitude dependent on ambient temperature when the solid-state light emitting component is driven under a constant current condition, said power control device comprising:

• a detection module including
• a voltage detecting unit to be connected electrically across the anode and the cathode of the solid-state light emitting component for detecting the forward voltage, and operable to generate a detection voltage according to the forward voltage detected by said voltage detecting unit, the detection voltage having a magnitude dependent on the forward voltage detected by said voltage detecting unit, and
• a current control unit to be connected electrically to the other of the anode and the cathode of the solid-state light emitting component, and operable to control flow of an operating current through the solid-state light emitting component according to a compensation voltage received by said current control unit, the operating current having a magnitude dependent on the compensation voltage received by said current control unit,
• said current control unit generating an operating voltage according to the operating current, the operating voltage having a magnitude dependent on the operating current;
• and
• a compensation voltage module connected electrically to said detection module for receiving the detection voltage and the operating voltage therefrom, disposed to receive a reference voltage, and configured to generate the compensation voltage for provision to said detection module according to the detection voltage, the operating voltage, and the reference voltage received by said compensation voltage module, the compensation voltage varying according to the forward voltage.

A compensation voltage module for use with a solid-state light emitting component and a detection module,

• the solid-state light emitting component having an anode and a cathode, one of which is disposed to receive an input voltage, and having a forward voltage that has a magnitude dependent on ambient temperature when driven under a constant current condition,
• the detection module including a voltage detecting unit and a current control unit,
• the voltage detecting unit being connected electrically across the anode and the cathode of the solid-state light emitting component for detecting the forward voltage, and being operable to generate a detection voltage according to the forward voltage detected by the voltage detecting unit, the detection voltage having a magnitude dependent on the forward voltage detected by the voltage detecting unit,
• the current control unit being connected electrically to the other of the anode and the cathode of the solid-state light emitting component, and being operable to control flow of an operating current through the solid-state light emitting component according to a compensation voltage received by the current control unit, the operating current having a magnitude dependent on the compensation voltage received by the current control unit,
• the current control unit being operable to generate an operating voltage according to the operating current, the operating voltage having a magnitude dependent on the operating current,
• said compensation voltage module being adapted to generate the compensation voltage that varies according to the forward voltage and comprising:
• an analog-to-digital conversion unit to be connected electrically to the detection module for receiving the detection voltage and the operating voltage from the detection module, disposed to receive a reference voltage, and operable to perform analog-to-digital conversion upon the detection voltage, the operating voltage, and the reference voltage so as to generate a digital detection signal, a digital operating signal, and a digital reference signal, respectively;
• a processing unit connected electrically to said analog-to-digital conversion unit for receiving the digital detection signal, the digital operating signal, and the digital reference signal from said analog-to-digital conversion unit, and operable to generate a digital compensation signal according to the digital detection signal, the digital operating signal, and the digital reference signal received by said processing unit;
• and
• a digital-to-analog conversion unit connected electrically to said processing unit for receiving the digital compensation signal from said processing unit, and operable to generate a compensation voltage signal according to the digital compensation voltage received by said digital-to-analog conversion unit, the compensation voltage corresponding to the compensation voltage signal.