氮化鎵(GaN)電晶體由於其閘極電荷小，且內部沒有寄生pn 二極體(body diode)，因 此可以達到非常快的切換速度與低硬切換損耗，非常適合應用於高壓電源轉換器。隨著 氮化鎵製程平台逐漸成熟，水平結構的氮化鎵電晶體能在單一晶片上實現閘極驅動器與 功率開關的積體化，從而降低電路的鎊線寄生效應。 本篇論文將氮化鎵功率開關與閘極驅動器積體化成半橋(half-bridge)晶片，並利用氮 化鎵電晶體反向傳導之特性將自舉開關同時進行積體化。透過分析功率開關切換過程的 能量轉換評估半橋晶片的損耗，並透過傳導損耗與輸出電荷(Qoss)之間的權衡選擇功率開 關的尺寸，並設計其閘極驅動器，在有足夠的驅動能力下也同時抑制閘極振鈴。 最後將此半橋晶片應用於降壓轉換器，此晶片能操作在500 kHz ~ 1 MHz 的切換頻 率，在切換頻率為1 MHz 時，可以實現48 V 到24 V 與12 V 的電壓轉換。操作於500 kHz 時可以實現100 V 到48 V 的電壓轉換。在48 V 到24 V 的電壓轉換與0.4 A 的輸出 電流下能達到91 %的峰值效率。;Gallium Nitride (GaN) transistors are highly suitable for high-voltage power converters due to their low gate charge and absence of a parasitic pn diode (body diode) within. These characteristics allow for rapid switching speeds and low switching losses, making them ideal for high-voltage power conversion applications. With the maturation of GaN fabrication processes, GaN transistors with lateral structures can be monolithically inte grated on a single chip, combining gate drivers and power switches to reduce circuit parasitics. This paper integrates gallium nitride power switches and gate drivers into a half-bridge chip and utilizes the reverse conduction characteristics of gallium ni tride transistors to integrate the bootstrap switch simultaneously. The losses of the half-bridge chip are evaluated by analyzing the energy conversion during power switch transitions. The sizing of the power switches is chosen through a trade-off between conduction losses and output charge (Qoss ), and their gate drivers are designed to provide sufficient drive capability and suppress gate ringing. Finally, this half-bridge chip is applied to a Buck converter. The chip can operate at switching frequencies between 500 kHz and 1 MHz. At a switching frequency of 1 MHz, it can achieve voltage conversions from 48 V to 24 V and 12 V. When operating at 500 kHz, it can achieve a voltage conversion from 100 V to 48 V. At a voltage conversion from 48 V to 24 V and an output current of 0.4 A, it can achieve a peak efficiency of 91%.
