Question

请英文高手帮我翻译一下，急急！100分赏，半个小时内有效

把这段话翻译成英文：
摘要：介绍一种采用半桥电路的开关电源，其输入电压为交流220V±20％，输出电压为直流4～16V，最大电流40A，工作频率50kHz。重点介绍了该电源的设计思想，工作原理及特点。关键词：脉宽调制；半桥变换器；电源

Answer 1

Abstract: A half-bridge circuit using the power switch, the input voltage for the exchange of 220 V ± 20%, the output voltage to DC 4 ~ 16 V, the largest current 40 A, the frequency of 50 kHz. Focused on the design of the power, principle and characteristics.
Key words: PWM; half-bridge converters; power