GaN-based power device is expected to be widely used in power converter system, owing to its superior characteristics of high-speed and high-efficiency, it is important that the dead-time related loss of GaN-based HEMT devices have negative impact on improving system efficiency in application of buck converter. In order to accurately assess the influence of the dead-time related loss on converter efficiency, analytical model combined with simulation results for dead-time related loss of GaN-based devices upon power converter system has been discussed and optimized in this letter. The different operating principle of buck converter system is discussed in Si-MOSFET and GaN HEMT and the mechanism of dead-time related loss is analyzed, respectively. for a converter of input voltage 12 V to output voltage 1.2 V, load current 20 A operating at a switching frequency of 700 kHz, the optimal efficiency is 92%under the conditions of Td1 is 20 ns, Td2 is 0 ns.%氮化镓功率器件以其优异的高速、高效特性而有望在电源转换领域取得广泛应用。在Buck开关电源应用中，系统采用GaN HEMT替换传统Si 功率器件后，系统死区损耗成为阻碍系统效率提升的一个重要因素。针对GaN 器件的电源转换系统死区功耗展开理论及仿真讨论，详细分析Si 功率器件与 GaN HEMT 在 buck 型开关电源系统中不同的工作机制以及死区时间对系统功耗的影响。优化结果表明，输入电压为12 V、输出电压为1.2 V、开关频率为700 kHz 的GaN 基电源转换系统，在死区时间Td1=20 ns、Td2=0 ns、负载电流为20 A 的情况下系统转换效率可达到92%。
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