【摘要】 电容式微机械超声换能器(CMUT)是一种新型超声换能器，具有高带宽、易与前端放大电路集成等优点，CMUT通过输出微弱的变化电流实现超声波回波检测。根据CMUT工作在发射与接收模式的特点，设计了一种具有发射开关保护功能和跨阻放大器的脉冲回波接收电路。波特图测量表明该电路的最大增益为39 dB,-3 dB带宽为24.2 MHz,涵盖了医学与工业超声检测常用的频率范围。分别对5.8 MHz和9.4 MHz的CMUT进行脉冲回波实验测试，测试结果表明：在CMUT发射模式下，该电路能够防止高压发射脉冲损坏后级的跨阻放大器电路；在CMUT接收模式下，该电路能够有效地将微弱电流信号转化为电压信号并进行放大。因此该电路能够用于CMUT的脉冲回波信号处理。更多还原

【Abstract】 The capacitive micromachined ultrasonic transducer(CMUT) is a kind of new ultrasonic transducer with the advantages of high bandwidth and easy integration with the front-end amplifier circuits.CMUT can detect ultrasonic echo waves by generating weak changing currents.According to the characteristics of CMUT working in transmit and receive mode, a pulse echo receiving circuit with a protect transmit switch and a transimpedance amplifier was designed.Bode plot measurement shows that the maximum gain of the circuit is 39 dB,and the-3 dB bandwidth is 24.2 MHz, which covers the common frequency range of medical and industrial ultrasonic testing.The 5.8 MHz and 9.4 MHz CMUT were tested by pulse-echo experiments, respectively.The test results show that in the CMUT transmission mode, this circuit can prevent the high-voltage transmission pulses from damaging the transimpedance amplifier circuit of the subsequent stage; in the CMUT receiving mode, this circuit can effectively convert the weak currents into amplified voltages.Therefore, this circuit can process the CMUT pulse-echo signals.更多还原