在本論文中，針對發光二極體(LED)驅動晶片(IC)中，包含保護電路、效率、電流精確度、過電流抑制等問題逐步改進其性能，進而延長電池與LED壽命，文中並提供理論上的分析與實務上的驗證。本論文所探討之LED驅動IC可用於可攜性消費性電子背光模組、汽車應用、顯示器與電視背光等應用。
在保護電路方面，本論文除了說明保護電路於LED驅動使用時的重要性，並提出三個保護機制，以避免LED、電感或驅動IC本身燒毀的狀況發生，此三種保護電路透過晶片實作與量測驗證了其保護功能。在功率轉換效率改進方面，分別利用整合蕭特基二極體與降低參考電壓的方式，減少外在元件的功率損耗，進而提升整體LED驅動器的功率轉換效率。對於LED的電流精確度，本論文提出具校正功能之高精確度LED電流驅動電路，利用校正誤差放大器的輸入偏移電壓，除可提高LED電流精確度外，並可增加功率轉換效率並減少誤差放大器之晶片面積；針對車用照明的LED驅動器，則整合類比與數位調光功能，此方法除了可以有效降低晶片封裝腳數，亦可減少車內燈光控制線路之繞線複雜度，以上兩點均可有效降低汽車電子成本。對於LED過電流抑制的控制電路，則針對LED驅動IC於PWM調光使用時LED過電流情況的改善情形，經與商用IC的量測比較，驗證本方法可有效延長LED使用壽命。最後，本論文實現一個高調光解析度的八通道整合型LED驅動晶片，僅使用單一輸入電壓，可同時驅動一個12x8的白光LED陣列，此雛型晶片除了利用量測儀器作功能量測外，亦透過驅動一個17吋的LED背光來驗證其產品之可行性。

This dissertation investigates the development of the light-emitting diode (LED) driver integrated circuit (IC). The efficiency, protection circuits, current accuracy, and over-current suppression of the driver are optimized. The LED lifetimes are also extended. The theoretical analysis is verified using a silicon prototype. The proposed LED driver IC can be used in backlights for portable electronic displays and TVs and automotive applications.
Three protection circuits which effectively protect the LEDs, inductor, and driver from damage are first presented. For high power conversion efficiency, an integrated Schottky diode is adopted to reduce the power consumption of off-chip devices. An offset calibration technique is used to enhance the LED current accuracy. This approach also decreases the chip area occupied by the error amplifier. For automotive applications, a hybrid dimming approach is proposed for processing both analog and digital dimming signals using only one pin. This technique reduces the wire routing complexity of automotive electronics. For pulse-width modulation dimming, an LED current suppression approach is proposed for extending the LED lifetime. Finally, an 8-channel, high-dimming-ratio LED driver with a 12x8 white LED array is applied to a 17-inch display to demonstrate the effectiveness and feasibility of the proposed techniques.

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