現今的發光二極體(LED)驅動器一般都使用脈波寬度調變(PWM)調光法，透過在恆定電流及零電流之間切換的方式改變平均電流，這種方式可以在保持色彩品質的同時改變LED的亮度。但是，在較低的驅動電流下LED的發光效率(lm/W)較高，因此PWM調光法的效率較類比調光法低。此外，於每個LED通道加入電流調節元件也會增加成本及功率損耗。
本文提出一種新型的LED驅動器，其可以將平衡的直流電流分配到多個LED通道，本文實做的LED驅動器為使用氮化鎵元件的1MHz，200W的LLC諧振轉換器。GaN高電子遷移率電晶體(GaN HEMT)相比於矽基的MOSFET，由於匝極電荷及輸出電容大幅降低，因此驅動損失更低，盲時區間也更短。故GaN HEMT在LLC諧振轉換器等高頻軟切換架構中有顯著的優勢。本文提出之LED驅動器透過將LLC諧振轉換器的輸出以相等的間隔分時多工的方式連接到每個通道，使其能在開迴路的情況下保持各通道電流相等。此外，不斷的變換導通順序以減少電流不平衡的可能性。本文實作之LED驅動器的最高效率達93.8%和最大9.9%的平衡電流誤差。

Modern-day light-emitting diode (LED) drivers typically utilizes pulse width modulation (PWM) to periodically switch between a constant current and a zero current to regulate the average LED current. This approach can alter LED brightness while maintaining color quality. However, the luminous efficiency (lm/W) of LEDs is comparatively high at lower driving currents, and as a result PWM dimming methods are less efficient than analog dimming ones. In addition, current regulation elements are inserted in individual LED channels, which increase the cost and incur power losses.

In this study, a novel LED driver that can distribute balanced dc currents to multiple channels of LEDs is presented, the realized LED driver adopts a 1 MHz, 200 W GaN-based LLC resonant converter topology. GaN High Electron Mobility Transistors (GaN HEMT) have lower driving loss and shorter deadtime due to significantly reduced gate charge and output capacitance compared to silicon-based MOSFETS. Therefore, GaN HEMTs exhibit significant advantages in high-frequency soft-switching resonant topologies such as an LLC resonant converter. The presented LED driver keeps the channel currents equal in an open-loop fashion by connecting the output of LLC resonant converter to each channel in a time multiplexing manner for an equal period of time. In addition, the sequence of conduction is repeatedly permutated to reduce possible imbalances among the currents. A prototype LED driver demonstrates the peak power efficiency of 93.8 % and maximum current balance error of 9.9 %.

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