A novel automatic power control system for a light emitting diode driving system

A feedback power control system includes: a multiplying unit receiving work voltage corresponding to the voltage drop in an electrical component and feedback voltage corresponding to the work current flowing through the electrical component, with outputting a measurement voltage corresponding to the power consumed by the electrical component, having a value equal to the product of the work voltage and feedback voltage. The control unit receives the measurement voltage from the multiplying unit and a reference voltage, and outputs a control voltage corresponding to the difference in voltage between the measurement voltage and the reference voltage. The regulating unit provides the feedback voltage to the multiplying unit and includes an amplifier that receives the feedback voltage from the electrical component. In this way, we can adjust the current flowing through the electrical component when the electrical component voltages vary with temperature. Reducing the power dependence of the electrical component to the temperature that compensates the temperature is our purpose. Both the automatic constant current and automatic power control can be provided by a single system.