Distributed circuit model for cold cathode fluorescent lamps in back-light unit of liquid crystal display

Abstract

This paper presents a distributed circuit model of the cold cathode fluorescent lamps (CCFLs) in the back-light units (BLUs) of liquid crystal displays (LCDs). This model consists of nonlinear resistors and parasitic circuit elements, and it can be used to simulate CCFL BLUs for various input waveforms using standard circuit simulators. The nonlinear resistors were modeled after the measured DC current-voltage characteristics of CCFLs. The coupling effects between CCFLs and between CCFL and the BLU frame were represented using the parasitic capacitances and inductances. For both pulsed and sinusoidal inputs, the voltage error between electrical simulation and measurement was <= 1.3% and the current error was <= 5.8%. These results demonstrate that the circuit model can be used to simulate the electrical behavior of CCFLs in LCD BLU accurately. (C) 2010 Elsevier B.V. All rights reserved.