LED灯驱动电路设计

led灯驱动电路设计

苏州大学

硕士学位论文

大功率LED驱动器的研究与设计

姓名：居大鹏

申请学位级别：硕士

专业：集成电路工程

指导教师：李富华

2010-10

led灯驱动电路设计

大功率LED驱动器的研究与设计 中文摘要

大功率LED驱动器的研究与设计

中文摘要

LED自从20世纪60年代问世以来，发展到今天，魅力四射，它是一种新型的半导体固态光源，具有高效、节能、环保、寿命长、应用灵活、控制方面等优点，属于典型的绿色照明光源。随着城市建设和电子信息产业的高速发展，人们对光源的需求与日俱增，LED产品的开发、研究和生产已成为发展前景十分诱人的朝阳产业，发展潜力空前巨大，已广泛应用在指示灯、交通信号灯、大型LED显示屏、LCD背光、城市夜景亮化等领越。近年来，在全球能源日趋紧张和全球气候变暖及环保压力日益加大的情况下，使用LED半导体照明已被公认为是节能环保的一种重要途径，我国已成为世界第一大照明电器生产国和主要出口国。伴随着对LED照明的急迫需求，LED在笔记本背光，液晶电视背光，汽车车灯上很快也会得到海量应用。LED的非线性特性决定了需要恒流驱动给它供电，一个好的驱动电源关系到整个系统的稳定可靠性。

本文针对LED的电学特性，研究设计了一款高恒流精度高效率电路结构简单的驱动芯片。该电路采用BUCK拓扑结构，具有频率可调、驱动电流可调、可调光（模拟调光和PWM调光）功能。合适驱动大功率LED灯串，电流驱动能力在10mA～1.2A可调，恒流精度控制在±3%以内，输入电压范围在4V～30V内。合适输入电源为5V，12V，24V的直流电源应用。

本文首先概述了国内外LED驱动器的研究现状和发展趋势然后讲述了LED的电学

特性并分析了LED驱动器的拓扑结构与控制方式，在此基础上设计了一款具有成本优势结构简单的大功率LED驱动芯片，本驱动芯片的设计主要包括电压基准模块、振荡器模块、峰值电流采样电路模块、PID补偿电路、驱动电路模块、逻辑电路模块、过温保护模块等功能模块。依据设计经验对各子模块功能和性能指标参数的分析、研究、优化。采用了PID电路补偿方法来提高LED恒流精度。

采用globalfoundries 0.35um CMOS工艺，在Candence设计平台上完成了PWM恒流驱动芯片的电路设计与版图设计。最后流片成功，对芯片进行测试验证，达到了预先的设计要求。本文最后还讲述了该驱动芯片的测试结果，包括功能和性能参数测试，然后对应用也作了简单的介绍。

关键词：LED恒流、PWM、调光、电流型

作 者：居大鹏

指导老师：李富华

led灯驱动电路设计

Study and Design of High Power LED Driver

Abstract

LED is glamorous since the inception of the 20th century, it is a new type of semiconductor solid-state light sources which owns high efficiency, energy saving, environmental protection, long life, flexible application and can be controled easily, etc., so it is a typical of green lighting source. With the urban construction and the rapid development of electronic information industry, the need of light for people is increasing.LED’s product development, research and production have become a very attractive prospect sunrise industry. It has been widely used in light,traffic lights, large LED display, LCD backlight and city’s night lighting. In recent years, global energy is becoming more tension and global warming and environmental’s protection under mounting pressure make that the use of LED semiconductor lighting has been recognized as an important means of saving and environmental protection, China has become the world's largest production of lighting appliances States and major exporting countries. With the urgent demand for LED lighting, the application on LED backlighting about notebooks, LCD TV backlighting, automotive lighting applications will soon be massive. The nonlinear characteristics of LED make that they should be powered with constant current driver, a good drive power be connected with the entire system stability and reliability.

In this paper, I have studyed and designed a simple constant current driver circuit with high precision and high efficiency under the electrical properties of LED.The circuit uses BUCK topology with adjustable frequency, adjustable drive current and adjustable light (analog dimming and PWM dimming) feature.It is suitable for high power LED light string, the current drive capability can be adjustable between10mA ~ 1.2A, constant current control accuracy within ± 4%, input voltage range is among 4V ~ 30V. It is suitable for 5V, 12V, 24V DC power supply’s applications.

This paper outlines the research at home and abroad LED drive current situation and development trends and then describes the electrical properties of LED and LED driver analyzes the topology and control, and then, a simple structure with a cost advantage for high-power LED driver chip is designed, the driver chip includes voltage reference module

led灯驱动电路设计

includes,the oscillator module, the peak current sampling circuit module, PID compensation circuit, driver circuit module, logic modules and over-temperature protection module function modules. Design experience based on each sub-module functions and performance parameters of analysis, research, optimization. PID compensation circuit is used to improve the LED constant current accuracy.

Globalfoundries 0.35um CMOS process is used in the design. Circuit design and layout design of the PWM constant current driver IC are finished in Candence. Finally, silicon was successful. Then I tested and validated the chip, found it accords with the pre-design requirements. Finally, this paper describes the results of the driver chip, including functional and performance testing, and then the applications are briefly introduced.

Keyword:LED constant current, PWM, dimming, current control

Written by: Dapeng Ju

Supervised by: Fuhua Li

led灯驱动电路设计

第一章 绪 论

1.1 引言

半导体照明（LED）作为一种新型光源，由于具有低温、省电、长寿命、无二次污染等特点，在低碳 、节能 、环保等一连串绿色概念盛行的今天，LED成为全球争相竞逐的一个新兴产业“制高点”，LED灯素有“绿色照明能源”之称，产品不含汞、铅等国际限制的六种有害物质，在同样亮度下，耗电仅为普通白炽灯的1/10,其寿命可以延长50倍，已成为世界上第四代节能产品的代表。

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