A High Accuracy Current-Balanced Control Technique for LED Backlight

被引:51
作者
Chiu, Chia-Lin [1 ]
Chen, Ke-Horng [1 ]
机构
[1] Natl Chiao Tung Univ, Dept Elect & Control Engn, Hsinchu, Taiwan
来源
2008 IEEE POWER ELECTRONICS SPECIALISTS CONFERENCE, VOLS 1-10 | 2008年
关键词
Current Balance; PWM Dimming; Open-Loop Detection;
D O I
10.1109/PESC.2008.4592615
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
This paper proposes a new circuit to regulate current in parallel LED (Light Emitting Diodes) strings. The new technique not only enhances the current matching in each string but also reduces device numbers and external resistance requirements. In this new circuit, the LED current has a low correlation to its forward voltage (V-f). The LEDs should have constant driving current as LCD backlight for two reasons. Firstly, keeping the maximum current and maintain the reliability. Secondly, obtaining expected luminous intensity for each LED. Furthermore, this circuit matches the current of eight LED strings and keeps high accuracy by using only two operational amplifiers. In other words, it reduces the power consumption and die size. There are two benefits for having just one resistance outside. Firstly, it can reduce pin numbers of the driving circuit. Secondly, it is easy for user to determine the maximum current of LED strings instead of predefined by the driving IC. The current accuracy of LED strings with a total forward voltage variation (Delta V) around 1.1V is less than 0.1%.
引用
收藏
页码:4202 / 4206
页数:5
相关论文
共 17 条
[1]  
Baddela SM, 2004, IEEE IND APPLIC SOC, P1677
[2]  
Chen CC, 2006, APPL POWER ELECT CO, P381
[3]  
CHIU HJ, 1954, IEEE T IND ELECTRON, V54, P2751
[4]   Digital architecture for driving large LED arrays with dynamic bus voltage regulation and phase shifted PWM [J].
Doshi, Montu ;
Zane, Regan .
APEC 2007: TWENTY-SECOND ANNUAL IEEE APPLIED POWER ELECTRONICS CONFERENCE AND EXPOSITION, VOLS 1 AND 2, 2007, :287-+
[5]  
*EV EL CO LTD, DAT LUM FULL COL LED
[6]  
*INT CORP, EL7801 INT CORP
[7]  
*LIGHT HOUS TECHN, 2008, 3508 SMD LED LIGHT H
[8]  
*LUM, DS51 LUM
[9]  
*MACR INC, 1916, MB1503016 MACR INC
[10]  
*MEX INT PROD INC, MAX16807MAX16808 MEX