【作者】 杨珂；

【导师】 解光军；

【作者基本信息】 合肥工业大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 白光LED是节能、环保、高效、长寿命的国际公认的下一代照明光源。白光LED已成为小型彩色LCD背光照明的最佳选择。随着白光LED技术的成熟，它将被更广泛地应用到各个领域。与传统光源不同，白光LED需要专用的驱动芯片才能使其高效持续地工作。本次课题研究紧密结合市场动态的发展，设计了一款应用于白光LED背光驱动的DCM-CPM型白光LED驱动芯片，该驱动芯片输出电流可调，工作在1.2MHz的固定频率下，最多可驱动4个串联的白光LED和提供可调的电流来控制亮度和色纯度，此芯片具有过流限制保护、电流检测和开负载保护等功能。本文首先完成了DCM-CPM型驱动电路的建模，然后对各个主要模块电路进行了设计与分析，例如振荡器、带隙基准源、电流检测放大器、误差放大器、PWM比较器、过流保护比较器等模块。在完成原理分析和电路设计的基础上，用EDA软件Cadence Spectre对各个子电路模块和整体电路进行了功能仿真，仿真结果均达到预定指标，验证了设计理论，说明本文设计的DCM-CPM型白光LED驱动芯片具有良好的性能。另外，整个环路是单极点系统，因此不需要补偿电路就能够保证系统的稳定性。更多还原

【Abstract】 White LED is now regarded as the next generation of light source because of its power saving, high efficiency, long life, low pollution and low radioactivity. White LED is become the best selection for small color LCD backlighting. With the maturating of White LED technology, it will be applied in many fields. Different from the traditional source, a special driver IC is needed for the White LED to maintain its normal working status.With an eye to the rapid market development, we design in this paper a DCM-CPM-White LED driver which is applied to White LED backlight driving with adjustable output current. It works at a fixed frequency, drive up to four White LED series and provide adjustable current to control brightness and color purity. This driver is featured by over-current protection, current detection and open-load protection features. This paper first completes DCM-CPM driver modeling, then designs and analyses each of the major modules of the circuit. For example, oscillator, band-gap reference source, the current detection amplifier, the error amplifier, PWM comparator, over-current comparator module and so on.Based on the analysis of circuit theory and the circuit topology, every module and the entire circuit are simulated by the Cadence Spectre tool. The simulation result not only meets with the target specification, but also verifies the design, which demonstrates the excellent performance of White LED driver IC realized by current-mode DC-DC converter technology. In addition, the loop is a single polar system and the whole circuit is so stable that no compensation circuit is needed.更多还原