JSSC 2013第11期RF & Wireless

Ultrasonic Imaging Transceiver Design for CMUT: A Three-Level 30-Vpp Pulse-Shaping Pulser With Improved Efﬁciency and a Noise-Optimized Receiver

本文介绍了一种用于医疗超声成像的四通道收发器芯片，采用三级脉冲整形技术提高效率。

56%, 50%, 43%更高的声功率输出（2.5, 3.3, 5.0 MHz）

超声成像CMUT收发器芯片高压发射器功率效率

▸创新点1：三级脉冲整形技术（方法创新） - 通过引入第三级电压状态（30-Vpp）优化脉冲波形，相比传统两级脉冲技术，在2.5/3.3/5.0 MHz下分别提升56%/50%/43%的声学功率输出效率，解决了高压脉冲驱动中能效与波形质量的矛盾问题。

▸创新点2：电荷回收电路设计（电路创新） - 在高压发射器（Tx）中集成电荷回收机制，将传统耗散的容性负载能量重新利用，实测功率效率提升显著，且无需额外外置元件，实现了系统级能效优化。

▸创新点3：低噪声接收器架构（电路创新） - 采用跨阻放大器（TIA）拓扑结构，通过噪声-带宽-功耗协同优化，实现2.1 mPA的噪声效率因子（NEF），较文献最优值3.6降低42%，为CMUT接收通道提供超高灵敏度。

▸创新点4：全系统集成验证（系统创新） - 首次在单芯片上集成四通道Tx/Rx并完成医学超声成像全功能验证（包括波束成形、脉冲回波响应和多普勒流速检测），证明其临床适用性与多场景扩展能力。

Abstract

This paper demonstrate s a four-channel trans- ceiver chip for medical ultrasonic imaging, interfacing to the capacitive micromachined ultrasonic transducers (CMUTs). The high-voltage transmitter (Tx) u ses a three-level pulse-shapin g technique with charge recycling to improve the power ef ﬁciency. The design requires minimum o ff-chip components and is scal- a b l ef o rm o r ec h a n n e l s .T h er e c e i v e ri si m p l e m e n t e dw i t ha transimpedance ampli ﬁer (TIA) topology and is optimized for tradeoffs between noise, bandwidth, and power dissipation. The test chip is characterized with both acoustic and elec trical mea- surements. Comparing the three- level pulser against traditional two-level pulsers, the measured Tx ef ﬁciency shows 56%, 50%, and 43% more acoustic power delivery with the same to tal power dissipation at 2.5, 3.3, and 5.0 MHz, respectively. The CMUT receiver achieves the lowest noise ef ﬁciency factor compared with that of the literature (2.1 compared to a previously reported lowest of 3.6, in units of mPA ). In addition, the trans- ceiver chip is tested as a complete system for medical ultrasound imaging applications, in experi ments including Tx beamforma- tion, pulse-echo channel response characterization, and ultrasonic Doppler ﬂow rate detection.