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WO2025015080A1 - Pixel ultrasonore ghz avec récepteur à étage unique à mélangeur passif - Google Patents

Pixel ultrasonore ghz avec récepteur à étage unique à mélangeur passif Download PDF

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Publication number
WO2025015080A1
WO2025015080A1 PCT/US2024/037433 US2024037433W WO2025015080A1 WO 2025015080 A1 WO2025015080 A1 WO 2025015080A1 US 2024037433 W US2024037433 W US 2024037433W WO 2025015080 A1 WO2025015080 A1 WO 2025015080A1
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WO
WIPO (PCT)
Prior art keywords
ultrasonic
pixel
pixels
passive mixer
transducer
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Application number
PCT/US2024/037433
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English (en)
Inventor
Justin Kuo
Serhan Ardanuc
Amit Lal
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Individual
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0688—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction with foil-type piezoelectric elements, e.g. PVDF
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/0207—Driving circuits
    • B06B1/0215—Driving circuits for generating pulses, e.g. bursts of oscillations, envelopes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8909—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using a static transducer configuration
    • G01S15/8915—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using a static transducer configuration using a transducer array
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
    • B06B2201/50—Application to a particular transducer type
    • B06B2201/55—Piezoelectric transducer
    • B06B2201/56—Foil type, e.g. PVDF
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
    • B06B2201/70—Specific application
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/52017—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00 particularly adapted to short-range imaging
    • G01S7/52079—Constructional features

Definitions

  • the present disclosure is directed to GHz ultrasonic imagers and, more particularly, to an ultrasonic transmit-receive pixel circuit for a transducer array.
  • GHz ultrasonic imager arrays have been realized by the fabrication of thin film piezoelectric MEMS ultrasonic transducers on a CMOS substrate on which pixel transmit and receive circuits are located.
  • This heterogeneous integration process is advantageous over other integration approaches such as flip chip bumping and wire bonding to MEMS transducers fabricated on a separate substrate in that the highest interconnect density can be achieved, resulting in the highest possible pixel densities, and that the lowest parasitic capacitances per pixel transducer can be realized, resulting in the highest possible ultrasonic signals.
  • the key invention from the previous incarnation of the pixel structure is the realization that there does not need to be an in-pixel amplifier within the pixel for the pixel signal to successfully propagate across a large array of pixels to the periphery of the array, where peripheral amplification, buffering, or processing circuits are situated.
  • the load capacitance on the pixel output which primarily stems from wiring capacitance and capacitive loading from other pixels, can combine with the mixer transistors within a pixel to form a sampling mixer, enabling the pixel to successfully operate without the need for an in-pixel amplifier.
  • a transimpedance amplifier situated at the end of a row of pixels can be used to reduce the effect of the load capacitance present on a pixel output.
  • the present disclosure is directed to an ultrasonic transmit-receive pixel circuit structure for a CMOS -integrated GHz ultrasonic transducer array that reduces the pixel size to further improve resolution.
  • CMOS -integrated GHz ultrasonic transducer array By eliminating an in-pixel amplifier, the size of a GHz ultrasonic pixel has been drastically reduced.
  • the architecture allows for much smaller pixel sizes compared to previous pixel circuit designs, enabling 25 um by 25 um sized pixels to be realized on a 130 nm CMOS process, compared with the 50 um by 50 um sized pixels previously achieved [2],
  • the pixel topology is designed to scale in size with the CMOS process node used to realize the structure, enabling even smaller pixel sizes to be realized by using more advanced CMOS process nodes.
  • the ultrasonic pixel structure comprise a piezoelectric ultrasonic transducer; at least one output wire; a passive mixer with at least one output terminal, wherein the transducer is connected to the input of the passive mixer and each output terminal of the passive mixer is connected to an output wire.
  • the piezoelectric transducer is aluminum nitride (AIN).
  • the passive mixer is implemented using CMOS transistors.
  • the passive mixer is operated as a sample and hold switch.
  • the ultrasonic transducer is fabricated on the same substrate as the passive mixer.
  • the ultrasonic transducer further includes at least one switch between the ultrasonic transducer and the passive mixer.
  • the ultrasonic transducer further includes at least one switch between an output terminal of the passive mixer and an output wire of the pixel.
  • the ultrasonic transducer further includes a transmitter circuit, wherein the transmitter circuit is connected to an ultrasonic transducer in the pixel structure.
  • the device comprises a plurality of ultrasonic pixels, wherein each ultrasonic pixel comprises at least one output wire; a passive mixer with at least one output terminal, wherein the transducer is connected to the input of the passive mixer and each output terminal of the passive mixer is connected to an output wire.
  • the output wires of a plurality of ultrasonic pixels are connected together on the same wire.
  • the phase at which a pixel demodulates is configurable.
  • the device further includes a transmitter circuit in each ultrasonic pixel, wherein the transmitter circuit is connected to an ultrasonic transducer.
  • the multiple pixels are configured to simultaneously transmit ultrasound.
  • the number of pixels that are transmitting is configurable to change the transmitted ultrasound beam pattern.
  • the phase at which a pixel transmits is configurable.
  • the ultrasonic pixel structure comprises a piezoelectric ultrasonic transducer; at least one output wire; a passive mixer with at least one output terminal; at least one capacitor; at least one switch, wherein the transducer is connected to the input of the passive mixer, each output terminal of the passive mixer is connected to a capacitor, the output of the capacitor is connected to the input of a switch, and the output of the switch is connected to the output wire.
  • the pixel structure further includes at least one switch between the ultrasonic transducer and the passive mixer.
  • the pixel structure further includes at least one switch between the passive mixer output terminal and a capacitor.
  • the ultrasonic pixel structure comprises a passive mixer circuit; multiple subpixel structures, wherein each subpixel structure comprises a piezoelectric ultrasonic transducer connected to a switch, wherein the passive mixer circuit input is connected to the subpixel switches to enable sharing of a receiver circuit between multiple transducers.
  • the pixel structure further includes a transmitter circuit that is connected to the subpixel switches to enable sharing of a transmitter circuit between multiple transducers.
  • FIG. 1 is a series of schematics of the basic structure of the pixel, namely: (a) a pixel comprising a transducer and a passive mixer receiver, (b) a pixel using a passive mixer with differential output terminals, (c) a pixel with an additional transmitter circuit, and (d) a pixel with transmitter circuit and differential outputs.
  • FIG. 2 is a schematic of an example of how the pixel can be arrayed to form a GHz ultrasonic imager where a 2D array of pixels is used, with pixels in each row and each column sharing several row wires and column wires, respectively.
  • Peripheral circuits situated at the edges of the rows and columns are used for functions such as control signal generation and buffering, bias circuit distribution, analog signal amplification or buffering, and data conversion or processing.
  • FIG. 3 is a schematic of a physical implementation of a GHz ultrasonic pixel where the receiver and transmitter circuits are fabricated using a CMOS process on a silicon wafer.
  • the transducer typically made from thin film piezoelectric aluminum nitride (AIN), is fabricated on top of the CMOS circuits.
  • the pixel can then be used to transmit ultrasound into the silicon or to receive incident ultrasound from within the silicon.
  • FIG. 4 is a pair of schematic examples of transistor level implementations of a passive mixer in the pixel, where: (a) the receiver mixer can be realized with a single transistor toggled by a gated local oscillator signal LO MIX; and (b) the receiver mixer can be realized with two transistors toggled by differential gated local oscillator signals LOP MIX and LON MIX.
  • FIG. 5 is a pair of schematics illustrating the mixer gate signals can be generated for: (a) a pixel with a single transistor passive mixer; and (b) a pixel with a single balanced passive mixer.
  • ROW and COL are the digital row and column select signals, respectively.
  • RX EN is a receive enable signal.
  • LO is a local oscillator signal, typically a GHz frequency square wave digital signal.
  • LO P and LO N are differential local oscillator signals, typically GHz frequency differential square wave digital signals.
  • FIG. 6 is a series of schematics illustrating examples of where switches can be inserted in the pixel, such as: (a) a switch can be placed between the transducer and the passive mixer; (b) a switch placed between the passive mixer and the transducer can be realized with a transistor M2; (c) a switch be placed between the passive mixer output and the pixel output; and (d) a switch placed at the output of the passive mixer can be realized with a transistor M2.
  • FIG. 7 is a series of schematics illustrating the outputs of multiple pixels, such as for all of the pixels in a row, can be connected together to share the same set of amplifiers.
  • the mixer transistors will be disabled and thus are represented as open switches.
  • the differential wires ROW OUT P and ROW OUT N shared by the row of pixels are loaded by capacitances Cl and C2. These capacitances are typically from the capacitances of the pixels and wiring capacitances but can also be realized using discrete capacitors.
  • FIG. 8 is a pair of schematics illustrating examples of how the load capacitance on a pixel output can be utilized: (a) combining with a mixer transistor to form a sampling mixer; and (b) combining with a mixer transistor, shown as a switch, to form a sample and hold circuit.
  • FIG. 9 is a schematic of an example transmitter circuit.
  • An AND gate is used to form an RF pulse by gating a RF local oscillator signal with a transmit pulse.
  • the generated RF pulse can be buffered by a buffer circuit that is sized appropriately to drive the load impedance of the transducer.
  • a switch is used between the buffer circuit and the transducer terminal to disconnect the transducer from the transmit driver when receiving from the transducer.
  • FIG. 10 is a series of schematics of examples of how the pixel receiver transistors can be biased in voltage or current mode operation: (a) a bias resistor can be placed at the input of the mixer within the pixel; (b) bias resistors can be placed outside of the pixel on the common analog output wires ROW P and ROW N shared by multiple pixels; and (c) the bias voltage for the mixer transistors in a pixel can be supplied by an external transimpedance amplifier.
  • FIG. 11 is a series of diagrams illustrating a multiple pixel transmit scheme, where transmit is performed using more pixels to increase the effective transmit aperture size, in a group of 7x7 pixels, where each square requires a pixel, and a square labeled TX represents a transmitting transducer as follows: (a) transmit is performed by a single transducer; (b) transmit is performed by a group of 3x3 pixels; (c) transmit is performed by a group of 5x5 pixels; and (d) transmit is performed by a group of 7x7 pixels.
  • FIG. 12 is a schematic illustrating that, to further reduce pixel sizes, the same transmitter and receiver circuits can be shared between multiple transducers.
  • FIG. 13 is an example of CMOS implementation of GHz ultrasonic pixel where: (a) an image of circuit layout of 2 pixel by 2-pixel unit cell; and (b) is a diagram of the layout of transducers in 2 pixel by 2 pixel unit cell.
  • FIG. 14 is a series of schematics of the ese of pixels in phased array configuration as follow: (a) a representation of a 2D pixel array; (b) different LO phases applied to pixels on different rows, requiring a phase shifter per row; (c) different LO phases per pixel, requiring a phase shifter per pixel; (d) a single phase shifter on the edge of a row of pixels can provide the phase shift needed for ID beamforming; and (e) one method to enable receive beamforming is by summing up the outputs of multiple pixels on a shared capacitor.
  • FIG. 15 is a schematic of ultrasonic pixel structure where a storage capacitor is integrated within the area of a pixel, where transistor Ml serves as both a mixer and a sample and hold switch and capacitor Cl serves as a storage capacitor.
  • FIG. 1 a circuit structure for an ultrasonic transmit-receive pixel 10 use in a CMOS- integrated GHz ultrasonic transducer array.
  • the circuit schematic for pixel 10 is seen in FIG. 1(a).
  • Pixel 10 comprises a piezoelectric ultrasonic transducer 12 that converts received ultrasonic signal 14, ultrasonic pulses into electrical pulses.
  • Transducer 12 is placed at the input of a passive mixer 16, so that the received ultrasonic pulses are downconverted by mixer 16 to a baseband signal, which is output from the pixel via an output terminal 18.
  • the lower frequency of the baseband signal enables the pixel output signal to propagate across long wires across an array of pixels to reach the edge of the array at which peripheral amplifiers, buffers, or processing circuits are located.
  • FIG. 1(b) the pixel structure shown in FIG. 1(b) is used, where a transmitter is connected directly to the transducer and to the passive mixer input.
  • Mixer 16 used in the pixel can have more than one output terminal 18.
  • Fig. 1(b) and 1(d) show the case when mixer 16 is used with a differential pair of outputs 18. Quadrature output mixers also will require more than one output terminal.
  • Pixel 10 is designed to be used in an array of pixels 10 to form an imager 20, although it can be used by itself in applications where only one transducer is required.
  • FIG. 2 where a 2D array of pixels 10 is shown.
  • These wires 22 serve to bring the output from the pixels 10 to the periphery of the array, bring power and ground to the pixels 10, and bring digital or analog control signals to the pixels 10.
  • Similar wires 24 run across an entire column of pixels.
  • These circuits can include digital control circuits and digital buffers for generating control signals pixel selection and pixel operation, and analog circuits for biasing, signal amplification or buffering, and data conversion or processing.
  • FIG. 3 The physical structure of a pixel 10 is shown in FIG. 3.
  • the pixel circuits are fabricated using a CMOS process on a silicon wafer.
  • the transducer is fabricated directly on top of the CMOS wafer and is typically realized using aluminum nitride (AIN) piezoelectric thin films. While a monolithic CMOS-MEMS integration scheme is shown in FIG. 3, the transducer does not need to be fabricated on the same substrate as the CMOS circuits, although doing so has advantages in higher signal strengths and higher achievable pixel densities. For example, it is possible to have a transducer fabricated on a separate substrate and use flip-chip bumps to connect the transducer to CMOS electronics.
  • AIN aluminum nitride
  • Passive mixer 16 used in pixel 10 can be implemented most simply as a single-ended mixer 16a with a single transistor 30, as shown in Fig. 4a, or as a single balanced mixer 16b with two transistors 30, as shown in Fig. 4b. Other variations are possible, for example to implement a double balanced mixer or a quadrature mixer. While an NFET transistor is shown in FIG. 4, a PFET or other type of transistor or switch can also be used to realize the mixer, because passive mixers are realized by modulating a switch at high frequency.
  • a passive mixer is defined as a mixer where the mixing operation is performed by a switching transistor or other device, where the switching device provides no power gain.
  • the signals applied to the gates of the passive mixer transistors can be generated with the circuits shown in FIG. 5.
  • pixel row and column select signals ROW and COL are ANDed together to form a pixel enable signal PIXEL EN.
  • the PIXEL EN signal is ANDed with a receiver enable signal RX_EN to form a mixer enable signal MIXER_EN.
  • the MIXER EN signal is then ANDed with local oscillator signals LO P and LO N for a single balanced mixer or a single local oscillator signal LO for a single-ended mixer to form the gated local oscillator signals applied to the gate of the mixer transistors.
  • switches can be placed between the transducer and the mixer input, between the mixer output and the pixel output, or both.
  • a switch placed between the transducer and the mixer input can allow for more receiver isolation when the pixel is being driven to transmit ultrasound.
  • a switch placed between the mixer output and the pixel output can have many uses, for example to form an analog multiplexer, to increase isolation between selected pixels and unselected pixels, or to form a sample and hold circuit.
  • the outputs of multiple pixels 10 can be connected together, as shown in FIG. 7.
  • This scheme allows a single wire or a pair of wires, or more depending on the number of outputs in a pixel 10, running across an array to be used to access the outputs of an entire row of pixels 10.
  • the passive mixer transistors in unselected pixels are disabled, thus acting as open switches. Therefore, only the signals from active pixels 10 can be read by the peripheral circuits located at the end of the row. While typically the output from only one pixel 10 on a shared output wire is read at one time, it is possible to receive from multiple pixels and sum up their outputs by operating the pixel receivers in current mode operation.
  • the pixel outputs are loaded by a load capacitance that primarily stems from the wiring capacitance and from the capacitances of the pixels sharing the same wire, although discrete capacitors can also be used.
  • This load capacitance may be used to form a sampling mixer with the mixer transistors, as shown in FIG. 8(a).
  • the load capacitance can also be used as a part of a sample and hold circuit, as shown in FIG. 8(b). This sample and hold circuit can be used to sample an echo at a selected time and hold the signal long enough to enable the use of a slow analog-to-digital converter.
  • the transmitter used in a pixel can be implemented by using an AND gate, a buffer, and a switch, as shown in FIG. 9.
  • An input local oscillator waveform typically a rail-to-rail GHz signal, is ANDed with an envelope pulse to create the RF pulse needed to actuate the transducer.
  • This generated pulse goes into an optional buffer circuit that provides the appropriate drive strength to drive the impedance of the transducer.
  • a switch is used to prevent the transducer from being driven when receiving signals from the transducer. Note that the buffer is only needed if the AND gate is unable to drive the capacitance of the transducer. Similarly, the switch can be removed if a tri-state buffer is used to achieve the same purpose of disconnecting a transmit driver from the transducer during receive mode.
  • the mixer transistors need to be biased at a high voltage such that there is enough headroom for the signal from the transducer to swing such that it does not get clipped.
  • a bias resistor can be placed within the pixel 10 at the input of the passive mixer 16, or outside the pixel 10 at the output of the passive mixer 16, where the same resistors will be shared by multiple pixels 10. These biasing schemes are more appropriate when the pixel signals are amplified using a voltage amplifier 40 followed at the end of the row.
  • a transimpedance amplifier 42 can be used, such as shown in FIG. 10(c). In this mode of operation, the bias resistors within the pixel can be removed, further reducing pixel size.
  • the resistors in FIG. 10 can be substituted with devices such as transistors.
  • the structure of pixel 10 allows for pixel sizes smaller than 50 um by 50 um in dimension. However, as the size of a pixel is reduced, the full-width half maximum (FWHM) of the transmitted ultrasonic beam from the pixel becomes wider, meaning that the acoustic beam becomes wider. If the FWHM of the transmitted ultrasound is much wider than the size of a pixel, then the resolution of the imager is degraded. To counteract this effect, multiple pixels can be configured to transmit at the same time, as shown in FIG. 11 for 3x3 pixels, 5x5 pixels, and 7x7 pixels.
  • the number of pixels that are being transmitted from is configurable to achieve the desired acoustic beam width and focal distance.
  • switches can be used in the LO distribution network to ensure that the same number of LO buffers is used for the LO signals entering each pixel.
  • Transmit transducers do not need to be immediately adjacent to each other, for example to synthesize an annular array.
  • the same transmitter and receiver circuits can be shared between multiple transducers, as shown in FIG. 12.
  • the pixel structure of FIG. ID may be implemented on CMOS to realize an effective 256 pixel by 255-pixel array with pixel pitch of 25 pm, as shown in FIG. 13.
  • the unit cell of the array is a 2 pixel by 2-pixel layout, to allow for sharing of wires and transducer ground vias.
  • both transmit beamforming and receive beamforming can be implemented, with phase shifters implemented per row or per pixel, as shown in FIG. 14.
  • Phase shifting per row enables ID beamforming and phase shifting per pixel enables 2D beamforming but also requires more pixel complexity.
  • the phase shifter does not need to be within the pixel and can be implemented on the edge of a row.
  • Transmit beamforming is performed by transmitting with different phases on different pixels.
  • Receive beamforming is performed by phase shifting the mixer local oscillator input and summing up the inputs of desired pixels.
  • the outputs of multiple pixels on the same row can be summed by using capacitors to sum up the outputs of multiple pixels at the same time.
  • the capacitors can be either from parasitic capacitance or discrete capacitors.
  • the pixel receiver comprises of a transistor Ml that is used as a mixer and a switch, a storage capacitor Cl, and a transistor M2 that is used as a switch for reading from the storage capacitor Cl.
  • An optional resistor R1 can be used to bias transistor Ml .
  • RXSH is a signal used to enable the mixer when the pixel is receiving ultrasound and also used in conjunction with capacitor Cl as a sample and hold.
  • RXSH is logic high, the mixer switch is enabled.
  • the falling edge of RXSH from logic high to logic low turns the mixer switch off, thus storing the echo signal with capacitor CL
  • the down-converted acoustic echo is sampled when MIXER EN is logic high and held when MIXER EN transitions from logic high to logic low.
  • the down-converted echo voltage is then held in capacitor Cl, until it is read through transistor M2.
  • a typical read operation would occur as follows.
  • the wire ROW OUT which is connected to the output of multiple pixels, is first precharged to a bias voltage, typically determined either by the appropriate input bias voltage for a sense amplifier connected to ROW OUT or set to half of the supply voltage to allow for maximum received signal swing.
  • the pixel is switched to receive mode to read the acoustic echo.
  • transistor Ml is operated as a mixer, with a LO frequency applied to its gate.
  • transistor Ml is switched off and the downconverted echo amplitude at the time of interest is stored within capacitor Cl .
  • transistor M2 which is normally off, is turned on and capacitor Cl shares its charge with the capacitance present on wire ROW OUT - this capacitance can be comprised of the parasitic capacitance present on that wire, as well as any discrete capacitors added to that wire.
  • the resulting signal on wire ROW OUT is then amplified by a sense amplifier.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Acoustics & Sound (AREA)
  • Mechanical Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

L'invention concerne un pixel ultrasonore destiné à être utilisé dans un imageur ultrasonore GHz. Le pixel est formé par un transducteur ultrasonore qui peut convertir un signal ultrasonore reçu par le transducteur ultrasonore en une série d'impulsions électriques. Un mélangeur passif est couplé au transducteur ultrasonore afin de recevoir la série d'impulsions électriques. Le mélangeur passif convertit en aval la série d'impulsions électriques en un signal de bande de base et délivre ensuite en sortie le signal de bande de base par l'intermédiaire de la borne de sortie. Le pixel ultrasonore peut comprendre un ou plusieurs commutateurs qui permettent au pixel ultrasonore de partager un circuit d'émission et de réception lorsqu'il est positionné dans un réseau.
PCT/US2024/037433 2023-07-10 2024-07-10 Pixel ultrasonore ghz avec récepteur à étage unique à mélangeur passif Pending WO2025015080A1 (fr)

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US202363525731P 2023-07-10 2023-07-10
US63/525,731 2023-07-10

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220043993A1 (en) * 2020-08-07 2022-02-10 Tdk Corporation Ultrasonic sensor with receive beamforming
WO2022125708A1 (fr) * 2020-12-08 2022-06-16 Geegah LLC Imagerie et détection de couche mince à l'aide de transducteurs ultrasonores haute fréquence
WO2022139821A1 (fr) * 2020-12-22 2022-06-30 Amit Lal Architecture de pixels d'imageur ultrasonore cmos ghz

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220043993A1 (en) * 2020-08-07 2022-02-10 Tdk Corporation Ultrasonic sensor with receive beamforming
WO2022125708A1 (fr) * 2020-12-08 2022-06-16 Geegah LLC Imagerie et détection de couche mince à l'aide de transducteurs ultrasonores haute fréquence
WO2022139821A1 (fr) * 2020-12-22 2022-06-30 Amit Lal Architecture de pixels d'imageur ultrasonore cmos ghz

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