Transmit and receive ASICs for an ultrasound imaging multi-element array transducer

High resolution focused beams of ultrasonic energy are used for imaging purposes for example by the medical profession and in non-destructive testing. High resolution beam focusing is achieved by pulsing the elements of an ultrasonic array transducer in some predetermined manner. This may take the form of a phased array, which allows for an electronically steered beam (sector scanning), or a linear array which typically would allow groups of elements to be successively pulsed along the array, or even a combination of the two. Conventional multi-element ultrasound transducer arrays are connected by long multi-wire cables to the system´s electronics and display unit. This can cause numerous problems including interference and reflections along the cables. The net effect of these is to make the system signal-to-noise ratio poorer. These effects are magnified if the system is designed to operate at higher than conventional ultrasound frequencies. Currently an Application Specific Integrated Circuit (ASIC), capable of providing sixteen programmable channels, each of 1 ns time resolution and with a dynamic range of 2¹⁹ (easily extendable), has been developed in 1.5-μm CMOS technology under the Eurochip initiative. The role of this chip is to provide delays of programmable length which determine the firing order of the high voltage pulse circuitry of the array elements. It Is envisaged that this ASIC will form part of a generic chip set for operating high frequency arrays in any mode