应用于电磁超声的DE类功率放大器驱动电路设计

Design of a DE Power Amplifier Drive Circuit for Electromagnetic Ultrasonic Source

为了进一步增强电磁超声激励源的激发效能,提高电磁超声换能器的工作效率,基于射频技术提出了一种DE类射频功率放大器,通过采用隔离电源方法,有效地解决了高边金属-氧化物半导体场效应晶体管(MOSFET)的"浮地"问题,实现了高频隔离.通过分析MOSFET开关工作状态及控制特性,确立了MOSFET开关的基本工作过程,从而建立了一种MOSFET驱动电路设计方法.通过对关键元件的选型设计与算法研究,构建了DE类功率放大器的驱动电路.实验结果表明:设计的MOSFET驱动电路的输出信号电压幅值为13.4 V,占空比50%,频率为1MHz,输出信号稳定,实现了对MOSFET的可靠驱动,能够满足实际应用.

In order to further enhance excitation efficiency of the electromagnetic ultrasonic excitation source,and to improve the work efficiency of the electromagnetic ultrasonic transducer,a Class-DE power amplifier based on the radio frequency(RF) technology was presented by using isolated power supply method.The high side metal-oxide-semiconductor field effect transistor(MOSFET) 'floating' problem was effectively solved.By analyzing the MOSFET switch working state and control characteristic,the basic process of MOSFET switch was established,thus a MOSFET driver circuit design method was built.Through selection of key components design and algorithm research,the DE class driver circuit of power amplifier was conducted.Experiments show that the output signal voltage amplitude of the MOSFET drive circuit is 13.4 V,the duty ratio is 50%,the working frequency is 1 MHz,the output signal is stable,the MOSFET reliable drive is obtained,and practical application is satisfied.