Patent ID: 9635718
Date: 2017-04-25
CPC Classifications: H05B

Claim:
1. A light emitting diode controlling circuit configured to control a buck-type driving circuit comprising a light emitting diode (LED) and a switch, comprising: a first integrator configured to integrate a voltage value across a resistor of a LED driving circuit; a second integrator configured to integrate a predetermined reference current value; a comparator configured to compare a first integral value output from the first integrator and a second integral value output from the second integrator; a set-reset (SR) flip flop configured to be reset according to a result of comparing the first integral value and the second integral value and to control the switch; and an off timer configured to count a driving time of the LED, to set the SR flip flop, to reset the first integrator and the second integrator when a counted driving time of the LED reaches a predetermined value, and to restart a count according to the result of the comparing.