BRIGHTNESS CONTROL CIRCUIT FOR LIGHT-EMITTING DIODE AND LIGHT-EMITTING DIODE LIGHTING DEVICE INCLUDING SAME

摘要

A brightness control circuit for a light-emitting diode includes an inverter generating a second sawtooth wave signal by inverting and amplifying a first sawtooth wave signal supplied from a DC-DC converter, and a comparator which receives a second sawtooth wave signal, generates a pulse width modulation signal by comparing the second sawtooth wave signal and a brightness indication signal, and provides a pulse width modulation signal to a light emitting diode circuit. The brightness control circuit for the light-emitting diode automatically controls the brightness of the light-emitting diode by detecting changes in voltage and current and constantly maintaining the voltage and current by using a sawtooth wave.