The present invention relates generally to ultrasound imaging systems. More particularly, the present invention relates to an integrated circuit for implementing high-voltage ultrasound functions of an ultrasound imaging system.
An acquisition sub-system 16 stimulates the piezoelectric transducer array 12 for the generation of an ultrasound wave. It also processes the electrical signals produced by the piezoelectric transducer array 12 from an incident ultrasound wave into a scan line. This scan line provides echogenic information about the tissues located on an axis emanating from the piezoelectric transducer array 12. A signal processing sub-system 18 converts the scan lines into an image. The image may be displayed, stored or forwarded to another system by the interface, storage and connectivity sub-system 20. A sub-system 22 provides user interface and control over the other sub-systems 16, 18 and 20.
The acquisition sub-system 16 is composed of identical channels where each deals with a single piezoelectric transducer from the piezoelectric transducer array 12. Generally, a piezoelectric transducer is used alternatively for both the generation and the reception of ultrasound waves. Each channel of the acquisition sub-system 16 thus includes a transmitter which provides a high-voltage signal to the piezoelectric transducer for the generation of an ultrasound wave, and a receiver which processes the electric signal created by an ultrasound wave absorbed by the piezoelectric transducer. A set of switches avoids the transmitter and receiver from interfering with each other.
The transmitter has the difficult task of amplifying a low-voltage, high frequency analog signal to high-voltage (typically 200 Vpp), high-current (typically +/−2 A) signal with low distortion. The transmitter includes discrete components, such as high-voltage transistors, low-voltage operational amplifiers, high-current buffers, transformers, capacitors, resistors, etc., for amplifying the low-voltage, high frequency analog signal. Accordingly, each amplifier of the acquisition sub-system 16 requires a high number of discrete components and occupies a significant board space in the system. The high number of channels in high-end ultrasound imaging systems (typically 128) results in a significant cost.
A need therefore exists for integrating the high-voltage functions of each transmitter of an ultrasound imaging system on a single integrated circuit. The single chip would greatly reduce the space required by the several discrete components of traditional ultrasound transmitter circuits which are used in achieving the high-voltage transmitter functions. Additionally, the discrete components used in traditional ultrasound transmitter circuits are optimized for other applications. Their size and power dissipation are thus higher than required. By tailoring the size and performance of all the components of the ultrasound imaging system, a single integrated circuit can offer better performance at lower power dissipation.
The present invention provides an integrated circuit for implementing high-voltage ultrasound functions of an ultrasound imaging system. The integrated circuit is packaged as an integrated chip. As such, the integrated chip of the present invention greatly reduces the space required by the several discrete components of traditional ultrasound transmitter circuits in achieving the high-voltage transmitter functions.
The integrated circuit is fabricated using silicon-on-insulator (SOI) technology. The integrated circuit is packaged as an integrated chip which integrates at least the following high-voltage ultrasound devices: gate-driver, power amplifier and transmit/receive switch for at least one channel. Optionally, a low-noise pre-amplifier and analog multiplexer can be added. The preferred SOI technology combines low-voltage CMOS technology, bipolar transistors with high-voltage, high-speed transistors that can sustain voltages in excess of ultrasound requirements on a single chip. The transistors are isolated from each other with dielectric. This results in significant area reduction versus competing technologies. It also provides for the integration on the same chip of digital logic, low-voltage and high-voltage analog functions. All these components are essential for a high-performance ultrasound transmitter.
Accordingly, the present invention integrates the building blocks of a prior art ultrasound transmitter circuit (low noise amplifier, gate driver, power amplifier, isolation diodes, T/R switches, analog multiplexer, etc.) on a single SOI chip and performs their respective functions. Moreover, the SOI integration provided by the present invention allows new functions to be added (e.g., dynamic biasing for power reduction) and new circuit techniques that are not practical or simply impossible with the several discrete components of prior art transmitter circuits.
These and other advantages will become more apparent from the following detailed description of the various embodiments of the present invention with reference to the figures wherein:
Image quality in an ultrasound system depends on many factors. One of them is the number of channels available. Prior art ultrasound imaging systems are limited to 128 channels, due to power consumption and board space. The present invention provides an integrated high-voltage SOI integrated circuit for allowing more channels to be used (e.g., 256 channels) and thereby, increase image quality. The performance of a single channel is also of prime importance. Metrics such as signal-to-noise ratio, distortion and slew-rate are improved significantly with the single SOI integrated transmitter of the present invention where parasitic components are kept to a minimum.
As shown by
The preferred SOI technology combines low-voltage CMOS technology, bipolar transistors with high-voltage, high-speed transistors that can sustain voltages in excess of ultrasound requirements on a single chip. The transistors on the SOI IC chip 100 are isolated from each other with dielectric. This results in significant area reduction versus competing technologies. It also provides for the integration on the same chip of digital logic, low-voltage and high-voltage analog functions. All these components are essential for a high-performance ultrasound transmitter.
The best way to implement the invention is to integrate as many functions of a single channel as possible onto the single chip 100, and integrate as many channels on the chip 100 as power dissipation and/or area will allow. The preferred SOI technology for the integrated circuit 100 is Philips EZ-HV, as it allows the necessary voltage range transistors (˜250 V), and offers low and medium voltage range bipolar and MOS transistors all integrated together on a single chip.
The SOI IC chip 100 takes a small amplitude analog or digital signal (low-voltage signal) signal generated by an ultrasound imaging system, such as the system shown by
The T/R switch 108, also on the same SOI chip 100, protects the receive electronics during transmit and offers a low impedance path to the ultrasound imaging system for at least one signal received from the ultrasound probe 108. The received signal is transmitted to the ultrasound imaging system, such as the system shown by
Accordingly, the present invention integrates the building blocks of a prior art ultrasound transmitter circuit (gate driver, power amplifier, isolation diodes, T/R switches, etc.) on a single SOI chip and performs their respective functions. Moreover, the SOI integration provided by the present invention allows new functions to be added (e.g., dynamic biasing for power reduction) and new circuit techniques that are not practical or simply impossible with the several discrete components of prior art transmitter circuits. Additional circuitry can be provided within the SOI chip, such as digital logic circuitry for synthesizing the signal waveform and circuitry for converting the synthesized signal waveform to the analog domain prior to performing high-voltage amplification.
An additional embodiment of the present invention provides for an ultrasound imaging system 300 for acquiring and displaying ultrasound images, such as medical images, in order to aid in diagnosis of health related conditions as shown in
The piezoelectric transducer array 302 emits ultrasound energy in the frequency range of between 20 KHz and 20 MHz. As the ultrasound energy is reflected by tissue and structures inside a patient, the reflected energy is detected by the array 302, which in turn, relays the energy data for each channel to a control unit 304 via the multiplexer.
The control unit 304 is in electrical communication with the handheld scanning device 302 via a cable 306, which, ideally, also provides power for operation of the piezoelectric transducer array 302. Other means of communicating between the control unit 304 and the handheld scanning device 302 may be employed in addition to or in substitution of the cable 306. Such other means of communication include Bluetooth, IEEE 802.11a/b/c, infrared, etc.
The control unit 304 contains a processor 308 configured to perform a variety of image analysis and manipulation functions, and one or more storage devices 310. The storage devices 310 provide both temporary storage of the raw data received from the handheld scanning device 302 and long-term storage of processed images. The storage devices 310 may be any combination of hard drives, writeable CD-ROMs or DVDs, memory modules, magneto-optical drives and magnetic media. The control unit 304 is additionally connected to a display device 312, such as a CRT or LCD screen, for displaying the ultrasound images. Also one or more user input devices 314 are provided, allowing an operator to issue commands to the control unit 304.
It is provided that the multiplexer can be provided within the at least one SOI IC chip 100. In an alternative embodiment of the system 300, the at least one SOI IC chip 100 is located within the control unit 304. In this embodiment, the multiplexer is located within the handheld ultrasound scanning device 302.
The described embodiments of the present invention are intended to be illustrative rather than restrictive, and are not intended to represent every embodiment of the present invention. Various modifications and variations can be made without departing from the spirit or scope of the invention as set forth in the following claims both literally and in equivalents recognized in law.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB05/52939 | 9/8/2005 | WO | 00 | 3/13/2007 |
Number | Date | Country | |
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60609674 | Sep 2004 | US |