Light power compensation device, light power compensation circuit, and detecting module

A light power compensation device for compensating light power of a controlled light-emitting device, the controlled light-emitting device being a controlled light-emitting diode (LED) or a controlled laser diode, the controlled light-emitting device having an anode for connection to a voltage node, and a cathode, said light power compensation device comprising:

• a temperature-detecting light-emitting device which provides a forward bias voltage thereacross that varies in a negative relation to change in environmental temperature when driven under a constant current, and which has an anode and a cathode, said temperature-detecting light-emitting device being a temperature-detecting LED or a temperature-detecting laser diode;
• and
• a light power compensation circuit electrically coupled to said temperature-detecting light-emitting device and to be electrically coupled to the controlled light-emitting device, said light power compensation circuit including:
• a detecting module including:
• a current source electrically coupled to said temperature-detecting light-emitting device, and providing a working current for said temperature-detecting light-emitting device;
• and
• a detector unit having a first detector input terminal electrically coupled to said anode of said temperature-detecting light-emitting device, a second detector input terminal electrically coupled to said cathode of said temperature-detecting light-emitting device, and a detector output terminal, said detector unit detecting the forward bias voltage across said temperature-detecting light-emitting device and providing a detector voltage at said detector output terminal, the detector voltage being proportional to the forward bias voltage;
• a compensation voltage converting module having a first compensator input terminal for receiving a first reference voltage, a second compensator input terminal for receiving a second reference voltage, and a third compensator input terminal electrically coupled to said detector output terminal for receiving the detector voltage, said compensation voltage converting module converting the detector voltage with reference to the first and second reference voltages into a compensation voltage which has a negative relation to change in the detector voltage;
• and
• a driving module having a driver input terminal electrically coupled to said compensation voltage converting module for receiving the compensation voltage, and a driver output terminal to be electrically coupled to the cathode of the controlled light-emitting device, said driving module converting the compensation voltage into a driving current which is proportional to the compensation voltage and which drives operation of the controlled light-emitting device.