Patent attributes
A circuit for controlling an LED with temperature compensation is employed in the LED-based system. The circuit of the invention linearly controls luminance and color of the LED according to temperature change and more precisely compensates for temperature-related variations in LED properties. Also, the circuit saves the cost of the product due to no requirement of a microprocessor. In the circuit, a waveform generator generates a sawtooth wave for Pulse Width Modulation (PWM) control. A temperature detector detects a voltage via a resistance value which is linearly variable according to changes in an ambient temperature. A PWM controller compares the sawtooth wave from the wave generator with the detection voltage from the temperature detector and generates a PWM voltage having a duty determined by the comparison result.
