Ultrasound circuits

Principal Investigators:

Charles Sodini, Anantha Chandrakasan, Hae-Seung Lee

Students:

Kailang Chen, Sunghyuk Lee

Description

The recent development of micro-electromechanical systems allowed fabrication of capacitive micromachined ultrasound transducers (CMUTs). A CMUT is a micromachined capacitor whose value changes according to the DC bias voltage or external pressure due to the physical deformation of the top plate by electrostatic force or external pressure. The major advantage of using this transducer for ultrasound imaging system is the potential for integration with supporting electronic circuits.

This project focuses on designing of portable ultrasound systems which can be integrated with CMUTs. A new system architecture for energy efficient 3D scan which enables digital beam-forming both in the receive(Rx) path and transmission(Tx) path is proposed. As for functional block, the power efficient analog to digital converter is critical part of Rx path design and high voltage pulse generator is required for Tx path. Due to the large number of channels, a high performance digital signal processor which can handle data from the multiple input channels in real time is also challenging design issue.

The project also tries to implement ultrasound Doppler measurement system within the same system architecture. Because of the small frequency shift and low amplitude in the received Doppler signal, the Doppler subsystem places stringent requirement on the analog front-end. Low noise and high dynamic range signal conditioning are some of the major design challenges.