8通道恒流LED驱动电路的设计
发布时间：2018-10-12 06:56
【摘要】：随着温室效应、能源危机以及生态环境的日益恶化,使得人们迫切希望能改变能源的获取方式以及提高能源利用率。在此背景下,发光二极管(LED,Light Emitting Diode)以其亮度高、高效能、寿命长,耗能低,污染小以及出色的色谱性能等优势进入人们的视野,它将代替白炽灯、高压气体放电灯和荧光灯等传统光源而成为新一代电光源。LED在众多方面的应用,极大推动了LED驱动芯片的研究与发展。然而LED的核心结构是PN结,其I-V特性曲线呈非线性关系,故电压的微小变化将引起LED电流的很大变化,严重时会导致白光LED的色彩也跟着发生变化。为了避免色彩的偏移和确保亮度的稳定,LED应当用恒流驱动。本文首先介绍了LED的一些特性,发光机理,连接方式,然后详细分析了各种常见LED驱动电路的原理以及各自的特性,接着对目前常使用的恒流IC系统方案进行分析,根据系统设计指标的要求,提出了本文的整体电路设计架构,结合整体电路的功能完成了以下几个关键子模块电路的设计,包括基准电压源电路、恒定电流源电路、输出驱动级电路以及温度保护电路。在详细分析模块电路的工作原理的基础上,运用Cadence仿真软件对子电路进行了功能验证和性能参数的仿真。然后对整体电路进行仿真和版图设计。本次采用了CSMC 0.8μm工艺制造,输入电压范围3.5V~6V,输出电流可根据实际需求做调整,且输出电流不随电源电压变化,在温度-40℃~125℃范围内有着很好的温度特性;输出端可以承受10V的电压,以满足多个LED串联的需求。与传统的恒流多通道LED驱动器相比,该结构具有良好的多通道驱动能力,较高的电流匹配精。
[Abstract]:With the Greenhouse Effect, the energy crisis and the worsening of the ecological environment, people are eager to change the way of energy access and improve energy efficiency. In this context, LED,Light Emitting Diode) (Light emitting Diode), with its advantages of high brightness, high efficiency, long life, low energy consumption, low pollution and excellent chromatographic performance, will replace incandescent lamps. High voltage gas discharge lamp and fluorescent lamp have become the new generation of electric light source. The application of LED in many aspects has greatly promoted the research and development of LED driver chip. However, the core structure of LED is PN junction, and its I-V characteristic curve is nonlinear, so the small change of voltage will cause a great change of LED current, and the color of white LED will also change. To avoid color offsets and ensure brightness stability, LED should be driven by constant current. In this paper, the characteristics, luminescence mechanism, connection mode of LED are introduced, then the principle of various common LED driver circuits and their characteristics are analyzed in detail, and then the current constant-current IC system scheme is analyzed. According to the requirements of the system design index, this paper puts forward the overall circuit design architecture, and completes the design of the following key sub-module circuits, including the reference voltage source circuit, the constant current source circuit, combined with the function of the whole circuit. Output drive stage circuit and temperature protection circuit. Based on the detailed analysis of the working principle of the module circuit, the function verification and the performance parameter simulation of the sub-circuit are carried out by using the Cadence simulation software. Then the whole circuit simulation and layout design. The output current can be adjusted according to the actual demand, and the output current does not change with the supply voltage. The output current has a good temperature characteristic in the temperature range of -40 鈩，
本文编号：2265202
[Abstract]:With the Greenhouse Effect, the energy crisis and the worsening of the ecological environment, people are eager to change the way of energy access and improve energy efficiency. In this context, LED,Light Emitting Diode) (Light emitting Diode), with its advantages of high brightness, high efficiency, long life, low energy consumption, low pollution and excellent chromatographic performance, will replace incandescent lamps. High voltage gas discharge lamp and fluorescent lamp have become the new generation of electric light source. The application of LED in many aspects has greatly promoted the research and development of LED driver chip. However, the core structure of LED is PN junction, and its I-V characteristic curve is nonlinear, so the small change of voltage will cause a great change of LED current, and the color of white LED will also change. To avoid color offsets and ensure brightness stability, LED should be driven by constant current. In this paper, the characteristics, luminescence mechanism, connection mode of LED are introduced, then the principle of various common LED driver circuits and their characteristics are analyzed in detail, and then the current constant-current IC system scheme is analyzed. According to the requirements of the system design index, this paper puts forward the overall circuit design architecture, and completes the design of the following key sub-module circuits, including the reference voltage source circuit, the constant current source circuit, combined with the function of the whole circuit. Output drive stage circuit and temperature protection circuit. Based on the detailed analysis of the working principle of the module circuit, the function verification and the performance parameter simulation of the sub-circuit are carried out by using the Cadence simulation software. Then the whole circuit simulation and layout design. The output current can be adjusted according to the actual demand, and the output current does not change with the supply voltage. The output current has a good temperature characteristic in the temperature range of -40 鈩，
本文编号：2265202
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