Patent ID: 9101032
Filing Date: 2015-08-04
Classification: H05B,Y02B

Abstract:
1. A device for emitting an LED, comprising: an LED string including a plurality of LEDs; an LED drive switch including a first end connected to a first end of the LED string; an LED driver for controlling an output current that is supplied to the LED string by controlling the LED drive switch; and a constant current/constant voltage driver for generating feedback information on an output voltage supplied to the LED string or the output current, wherein the LED driver uses the output current to sense an open lamp state of the LED string, and uses a voltage at the first end of the LED drive switch to sense a change of the LED string to a normal state from the open lamp state, wherein the LED driver senses a change to the normal state from the open lamp state according to a result of comparing the voltage at the first end of the LED drive switch and a normal reference voltage.