一种带输出电压反馈的恒流驱动IC设计

An IC Design of Constant Current Driver with Voltage Output Feedback

在应用于液晶显示器(liquid crystal display,LCD)背光的发光二极管(light emitting diode,LED)驱动器中,传统设计的DC-DC电路是根据最大负载设计DC-DC电源,在负载有偏差的情况下,系统效率低下,且发热导致额外功率损失.针对传统电路不能动态调节输出电压的缺陷,提出一款新型的LED驱动器的设计.芯片采用恒流驱动模式,通过脉冲宽度调制(pulse width modnlation,PWM)数字模块控制,达到高灰度显示的要求;同时提供一个可级联的反馈电流输出端,配合DC-DC转换器,调节DC-DC的输出电压,以保证恒流输出驱动电压的同时,限制芯片功耗的增加.芯片测试符合设计要求,性能稳定.

To the LED drivers applied in the field of LCD backlight,the traditional design of the DC-DC circuit is based on the maximum load to design the DC-DC power supplies. When there are deviations in the load,the system inefficient and fever, which lead to additional power loss. According to the deficiencies that traditional circuit can not dynamically adjust output voltage,a new type of LED driver design is introduced. The chip achieves a high grayscale display requirement, with constant current drive mode used and controlled by PWM digital module. The chip also provides a feedback current output which can be cascaded, with DC-DC converters, regulate DC-DC output voltage to ensure constant-current output voltage and restrict the power consumption increasing. The chip testing meets the design requirements, performance stable.