Probe and ultrasonic diagnostic apparatus using the same

Abstract

This invention provides a probe and an ultrasonic diagnostic apparatus using the same. The probe, which incorporates a TGC circuit, has multiple receiving circuits. Each receiving circuit includes a vibrator, a transmit / receive switch, a variable attenuator, a first capacitor, and an amplifier. The vibrator converts the received signal into a ground-level electrical signal and outputs it as a first output signal. The transmit / receive switch is connected to a first signal line and switches whether the first output signal from the vibrator is output to the first signal line. The variable attenuator has a control terminal and two other terminals, and the resistance between the two terminals (excluding the control terminal) changes based on a control signal input to the control terminal. The amplifier includes at least an amplification circuit, with its input terminal connected to the first capacitor, amplifying the electrical signal from the first signal line and outputting it to a second signal line. One of the two terminals of the variable attenuator (excluding the control terminal) is connected to the first signal line, and the other terminal is grounded via a second capacitor (different from the first capacitor).

Description

Technical Field

[0001] This invention relates to probes suitable for ultrasound diagnostic devices and ultrasound diagnostic devices. Background Technology

[0002] In recent years, to obtain 3D (Dimensional) images using ultrasound diagnostic devices, 2D array probes have been developed, which are obtained by arranging vibrators in 2D. In a 2D array probe, the vibrators carry thousands to 10,000 elements; in contrast, the number of signal lines in the cable connecting the probe and the main body of the ultrasound diagnostic device is limited to 200. Therefore, a structure disclosed in Patent Document 1 and Non-Patent Document 1 is as follows: receiving beamforming within the main body of the ultrasound diagnostic device is divided into two stages. The first stage of receiving beamforming is performed by an integrated circuit (IC) disposed within the probe, and the signal after receiving beamforming in the first stage is output from the probe to the ultrasound diagnostic device. The IC disclosed in Patent Document 1 and Non-Patent Document 1 integrates vibrators and a transceiver circuit of the same number as the vibrators. A transceiver switching switch, an amplifier, and a delay circuit are provided in the receiving circuit to delay the amplified received signal before summing.

[0003] Generally, ultrasound diagnostic probes are systems that emit ultrasound waves and receive their reflected waves. Therefore, when acquiring images of areas close to the body surface, they receive ultrasound waves with high sound pressure caused by reflections from bones, etc., while when acquiring images of areas far from the body surface (deeper areas), they receive ultrasound waves with low sound pressure that attenuate as they propagate within the body. Therefore, in conventional ultrasound diagnostic devices that are not 2D array probes, a circuit called time gain control (hereinafter also referred to as "TGC") is incorporated into the main body of the ultrasound diagnostic device to increase the amplification gain of the received signal based on the elapsed time since the start of reception.

[0004] For example, the ultrasonic diagnostic device disclosed in Patent Document 2 transmits ultrasonic waves from a probe into the body of the patient. The probe receives the ultrasonic waves reflected within the patient, and the receiving unit within the main body of the ultrasonic diagnostic device processes the received signal. The receiving unit has the following structure: a transmit / receive switching unit prevents the transmitted signal from winding into the receiving unit, and an amplification unit amplifies the received signal received through the transmit / receive switching unit. Furthermore, a variable attenuation unit is arranged between the transmit / receive switching unit and the amplification unit to attenuate the received signal. The transmit / receive switching unit is composed of a diode bridge. The variable attenuation unit has the following structure: two circuits, obtained by connecting a resistor, a diode, and a variable bias voltage source in series, are connected in parallel. The resistor side is connected to the signal line flowing with the received signal, and the variable bias voltage source side is grounded. In the case of a received signal with a large amplitude reflected near the body surface, the bias voltage of the variable bias voltage source is set to turn on the diode, and the received signal is attenuated by voltage division through the resistor. When receiving signals with small amplitude reflected from deep regions of the object being examined, the bias voltage of the variable bias voltage source is adjusted to cut off the diode. This causes the attenuation to decrease over time.

[0005] Patent Document 3 discloses that in an ultrasonic image receiving circuit, the gain of the amplifier is set to be variable by changing the bias current of the preamplifier connected to the transducer element, or by adjusting the feedback of the differential output amplifier located after the preamplifier (Patent Document 3). Figure 3 , Figure 4 ).

[0006] Prior art literature

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-81451

[0009] Patent Document 2: Japanese Patent Application Publication No. 2013-188421

[0010] Patent Document 3: U.S. Patent No. 8,226,563

[0011] Non-patent literature 1: Kajiyama, S.; Igarashi, Y.; Yazaki, T.; Katsube, Y.; Nishimoto, T.; Nakagawa, T.; Nakamura, Y.; Hayashi, Y.; Yamawaki, T., "T / R-Switch Composed of 3High-Voltage MOSFETs with 12.1μW Consumption That Can Perform Per-Channel TXto RX Self-Loopback AC Tests for 3D Ultrasound Imaging with 3072-ChannelTransceiver, "IEEE Asian Solid-State Circuits Conference Proceedings of Technical Papers, pp. 305-308, Nov. 2019." Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] The receiving circuit configured in the 2D array probe described in Patent Document 1 and Non-Patent Document 1 does not have a circuit for time gain control.

[0014] On the other hand, the circuits for time gain control in Patent Documents 2 and 3 are both located within the main body of the ultrasonic diagnostic device. Therefore, from any point of view regarding space, power consumption, and circuit structure, they cannot be directly mounted within the tiny integrated circuits of the 2D array probe.

[0015] Specifically, the ultrasonic diagnostic device disclosed in Patent Document 2 requires a control signal to control the voltage of the bias voltage source in the variable attenuation section for realizing time gain control, but the generation of the control signal needs to be performed in an external circuit. Even assuming that the variable attenuation section can be integrated into the IC inside the probe, the external circuit for generating the control signal is still located within the main body of the ultrasonic diagnostic device, thus requiring the generated control signal to be sent to the signal line inside the probe. However, there is a limitation on the number of signal lines connecting the probe and the main body of the ultrasonic diagnostic device.

[0016] Furthermore, Patent Document 2 uses a diode for the variable attenuation section, but diodes have high drive power. Even assuming the variable attenuation section can be integrated into the IC within the probe, a large drive power would be required to supply the IC within the probe, leading to an increase in probe temperature. In addition, there are issues such as large performance deviations in diodes and large deviations in the attenuation of the variable attenuator.

[0017] Furthermore, the transmit / receive switching switch of the receiving circuit in Patent Document 2 is composed of a diode bridge, but the diode bridge is prone to fluctuations in the received signal output during switching.

[0018] On the other hand, in the ultrasonic device of Patent Document 3, a current feedback type with variable bias current and MOSFET used as a resistor is used to achieve variable gain by performing TGC via a preamplifier and varying the bias current. However, the gain variation that can be achieved by varying the bias current is small. Furthermore, distortion increases when the current value is small. In addition, when using a MOSFET as a resistor for current feedback, the process dependence of the gain increases.

[0019] In 2D array probes, each of the thousands to tens of thousands of elements in the oscillator array requires an independent low-noise amplifier (LNA) with variable gain functionality. In the receiver circuit structures described in Patent Documents 2 and 3, it is difficult to minimize the gain deviation of each LNA while simultaneously providing the required variable gain functionality (30 dB or more) for thousands to tens of thousands of LNAs. Therefore, it is impossible to achieve a structure that supplies gain control signals to multiple LNA groups mounted on an integrated circuit and performs TGC control without increasing the area of ​​each LNA.

[0020] Furthermore, the inventors discovered that in the receiver circuit structure of the probes disclosed in Patent Document 1 and Non-Patent Document 1, the bias potential of the signal line that sends the received signal to the amplifier circuit changes when the transmit / receive switch is in the off state (transmitting) and on state (receiving). Therefore, when the attenuation circuit for time gain control is configured in the pre-amplifier stage, the received signal is affected by the change in bias potential.

[0021] The purpose of this invention is to solve the above-mentioned problems and provide a probe with an internal TGC circuit.

[0022] Methods for solving problems

[0023] An example of the probe of the present invention used to solve the above-mentioned problems is: it is connected to an ultrasonic diagnostic device, sends ultrasonic waves to the diagnostic site and receives a received signal as a reflected wave, and has multiple receiving circuits.

[0024] Each receiving circuit includes a vibrator, a transmit / receive switch, a variable attenuator, a first capacitor, and an amplifier.

[0025] The vibrator converts the received signal into an electrical signal at ground level and outputs it as the first output signal.

[0026] The transmit / receive switch is connected to the first signal line to switch whether to output the first output signal from the vibrator to the first signal line.

[0027] The variable attenuator has a control terminal and two other terminals. Based on the control signal input to the control terminal, the resistance value between the two other terminals changes.

[0028] The first capacitor is connected to the first signal line.

[0029] The amplifier includes at least: an amplification circuit, an input terminal connected to a first capacitor, which amplifies the electrical signal of the first signal line and outputs it to the second signal line.

[0030] When the transmit / receive switch is open, it outputs a bias potential to the first signal line.

[0031] One of the two terminals other than the control terminal of the variable attenuator is connected to the first signal line, and the other terminal is grounded via a second capacitor, which is different from the first capacitor.

[0032] Invention Effects

[0033] According to the present invention, it is possible to provide a probe that has an internal TGC circuit.

[0034] Other issues, structures, and effects not mentioned above will be explained in the following description of the implementation methods. Attached Figure Description

[0035] Figure 1 This is a block diagram showing an outline of an integrated circuit (2D array IC50) in the probe of Embodiment 1, which carries multiple transceiver circuits (transceiver channels ECh).

[0036] Figure 2 This is a block diagram showing the structure of a transceiver circuit (transceiver channel ECh) in the probe of Embodiment 1.

[0037] Figure 3 This is a graph showing the time variation of the TGC control signal 10 received by the probe from the main body of the ultrasonic diagnostic device in Embodiment 1.

[0038] Figure 4 This is a graph showing the frequency versus attenuation characteristics of the variable attenuator 300 of the probe in Embodiment 1.

[0039] Figure 5 This is a block diagram showing an outline of an integrated circuit (2D array IC50) in the probe of Embodiment 2, which carries multiple transceiver circuits (transceiver channels ECh).

[0040] Figure 6This is a block diagram showing the structure of a transceiver circuit (transceiver channel ECh) in the probe of embodiment 3.

[0041] Figure 7 In implementation method 3, a 2.5MHz sine wave signal is input to... Figure 6 The spectrum of the output signal when the variable attenuator is 300.

[0042] Figure 8 This is a block diagram showing the structure of the ultrasound diagnostic device in Embodiment 4.

[0043] Symbol Explanation

[0044] 11~MN……Transmit / receive channel ECh (transmit / receive circuit)

[0045] 10……TGC control signal

[0046] 20……TGC control signal generator

[0047] 22, 22', 23... Output current

[0048] 24a……back grid

[0049] 24b……back grid

[0050] 30……Attenuator control signal

[0051] 40……Second capacitor (shared capacitor)

[0052] 41……pad

[0053] 42……Third capacitor

[0054] 43……pad

[0055] 50……2D Array IC

[0056] 100... Vibrator

[0057] 200……Transmit / Receive Switch

[0058] 203... Floating Voltage Generation Section

[0059] 204……Switching element

[0060] 204a……Switch Terminal

[0061] 204b... Connecting Terminal

[0062] 204c... Disconnect terminal

[0063] 206... Bypass signal line

[0064] 300... Variable attenuator

[0065] 302a...back grille

[0066] 302b...back grille

[0067] 400... amplifier

[0068] 401... Capacitor No. 1

[0069] 402... Low Noise Amplifier (LNA)

[0070] 500... Signal Line 1

[0071] 501...terminal

[0072] 502... Signal Line 2

[0073] 503... Wiring

[0074] 600… Transmitting circuit

[0075] 700… Receiver circuit

[0076] 800...delay circuit

[0077] 900... Addition circuit

[0078] VIC21... Voltage-to-current converter

[0079] CM21... Current Mirror

[0080] MN201, MN202... High-voltage N-channel MOSFETs

[0081] MN21b, MN301b... N-channel MOSFET

[0082] MP21a, MP301a... P-channel MOSFETs

[0083] R205... resistor

[0084] VSW... control signal

[0085] Ibias……Bias current

[0086] VDD1, VDD2, VDDS, VSS2... power supplies

[0087] R M_Nearest ...wiring resistance

[0088] R M_Farest ...wiring resistance

[0089] US10, US11... 2D array probes

[0090] US20, US21... cables

[0091] US30, US31... connector boxes

[0092] US40... Detector Selector

[0093] US120, US121... amplifiers

[0094] US51...Digital-to-analog converter

[0095] US320... Transceiver switch

[0096] US54...Analog-to-digital converter

[0097] US60...Signal Processing Circuit

[0098] US70... Control Panel

[0099] US80... Monitor

[0100] US90...Main Unit

[0101] US200, US201... Matching layer

[0102] US210, US211... Acoustic Lenses

[0103] US1000, US1001... casters. Detailed Implementation

[0104] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. Furthermore, in the drawings used to describe the embodiments, the same components are labeled with the same names and symbols, and repeated descriptions are omitted.

[0105] The designations "first," "second," "third," etc., used in this specification are for identifying constituent elements and do not necessarily limit the number or order. Furthermore, the numbers used to identify constituent elements are used in each context, and a number used in one context is not necessarily required to represent the same structure in other contexts. Moreover, this does not preclude a constituent element identified by a certain number from also having the function of a constituent element identified by other numbers.

[0106] <<<Implementation Method 1>>>

[0107] The probe used in the ultrasonic diagnostic device of Embodiment 1 will be described using the accompanying drawings. Figure 1 This is a schematic diagram showing an integrated circuit (2D array IC50) containing multiple transceiver circuits (transceiver channels ECh) within the probe. Figure 2 This is a diagram showing the structure of a transceiver circuit (transceiver channel ECh).

[0108] <Probe Overview>

[0109] In Implementation Method 1, the ultrasonic probe is connected to an ultrasonic diagnostic device, sends ultrasonic waves to the target area of ​​the subject, and receives ultrasonic signals as reflected waves.

[0110] The probe contains a 2D array of vibrators 100. The number of vibrators is, for example, several thousand to ten thousand elements.

[0111] like Figure 1 as well as Figure 2 As shown, the probe includes multiple vibrators 100, multiple transmitting circuits 600 that output signals to the vibrators 100 respectively, multiple receiving circuits 700 that delay the received signals of the vibrators 100 after processing such as time gain control, an adding circuit 900 that adds the outputs of the multiple receiving circuits 700, and a TGC control signal generator 20.

[0112] The aforementioned vibrator 100, transmitting circuit 600, receiving circuit 700, and summing circuit 900 are integrated on a 2D array IC50.

[0113] Through the circuits of the aforementioned 2D array IC50, the received signal output by the vibrator 100, after undergoing time gain control and amplification processing, is subjected to the first stage of received beamforming (here, delay addition), and bundled according to each sub-channel (hereinafter also referred to as Sch (Sub Channel)). The number of signals in the bundled sub-channels is less than or equal to the number of signal lines in the cable connecting the probe and the main body of the ultrasonic diagnostic device (for example, approximately 200), and is input to the main body of the ultrasonic diagnostic device through signal line transmission.

[0114] The main body of the ultrasound diagnostic device performs the second stage of receiving beamforming through internal circuitry, aligning the focal point with the receiving focal point at each depth on the receiving scan line set within the subject, generating a signal after the whole phase is added together.

[0115] The main body of the ultrasound diagnostic device uses the summed signals to generate tomographic images and 3D volume data of the subject.

[0116] <Circuit inside the probe>

[0117] For the circuitry inside the probe, use Figure 1 as well as Figure 2 Let me explain in detail.

[0118] As described above, the probe is equipped with multiple vibrators 100, multiple transmitting circuits 600, and multiple receiving circuits 700.

[0119] like Figure 2 Thus, a vibrator 100, a transmitting circuit 600, and a receiving circuit 700 constitute the element channel ECh. Multiple (M×N) element channels ECh11 to EchMN are arranged in a 2D matrix and mounted on a 2D array IC50. All M×N element channels ECh11 to EchMN are designed with the same circuit constants.

[0120] The receiving circuit 700 includes a transmit / receive switch 200, a variable attenuator 300 for time gain control, an amplifier 400, and a delay circuit 800. The transmit / receive switch 200 and the amplifier 400 are connected via a first signal line 500. The variable attenuator 300 is connected midway to the first signal line 500. The delay circuit 800 is connected to a second signal line 502 at the output of the amplifier 400. Additionally, the delay circuit 800 is also connected to the transmitting circuit 600 to delay the transmitted signal.

[0121] *Vibrator*

[0122] When transmitting, the vibrator 100 receives the transmission signal from the transmitting circuit 600, converts it into an ultrasonic signal, and transmits it to the object under test. When receiving, the vibrator 100 converts the ultrasonic signal reflected from the object under test into a ground level electrical signal and outputs it as the first output signal to the transceiver switch 200.

[0123] *“Transmit / Receive Switch 200”*

[0124] The transmit / receive switch 200 is a switch that toggles whether the first output signal from the vibrator 100 is output to the first signal line 500. During transmission, by switching the transmit / receive switch 200 to the off position, the downstream receiving circuit 700 is protected from the large-amplitude transmission signal output from the transmitting circuit 600 to the vibrator 100.

[0125] The transceiver switch 200 includes one or more high-voltage MOSFETs (MN201, 202 of N-channel MOSFETs) for transceiver switching, a floating voltage generation unit 203, a switching element (SW) 204, a resistor R205, and a bypass signal line 206.

[0126] The sources and gates of MOSFETs MN201 and MN202, which are used for the transmit / receive switching switch, are interconnected. The drain of MOSFET MN201, which is used as the transmit / receive switching switch 200, is connected to the oscillator 100, and the drain of MOSFET MN202, which is used as the other MOSFET, is connected to the first signal line 500.

[0127] The floating voltage generation unit 203 is, for example, Non-Patent Document 1. Figure 4 The circuit shown generates a voltage applied between the gate and source of MN201 and MP202.

[0128] The switching element 204 has a switching terminal 204a connected to the power supply VDD1, as well as an on terminal 204b and an off terminal 204c.

[0129] The switch terminal 204b is connected to the floating voltage generating unit 203. When the switch terminal 204a is connected to the switch terminal 204b side (when receiving ultrasonic waves), the switch element 204 supplies a bias current Ibias to the floating voltage generating unit.

[0130] On the other hand, the disconnect terminal 204c is connected to the first signal line 500 via the bypass signal line 206. When the connection between the switch terminal 204a and the disconnect terminal 204c is broken (when sending ultrasonic waves), the bias current Ibias flows directly into the first signal line 500.

[0131] Therefore, the transmit / receive switch 200 can switch whether to output the first output signal from the vibrator 100 to the first signal line 500.

[0132] Furthermore, when the switching element 204 is turned on, the bias current Ibias flows from resistor R205 to ground via the floating voltage generation unit 203 and MN202. On the other hand, when the switching element 204 is turned off, the bias current Ibias flows from resistor R205 to ground via the bypass signal line 206. Therefore, since the bias current Ibias always flows to resistor R205, the potential of the first signal line 500 becomes the potential determined by the product of resistor R205 and bias current Ibias. In other words, the transceiver switch 200 outputs a bias potential to the first signal line 500 when the switch is off. Moreover, the bias potential output by the transceiver switch 200 to the first signal line 500 when the switch is off is equal to the bias potential output by the transceiver switch 200 to the first signal line when the switch is on. Therefore, the potential of the first signal line 500 can be kept constant regardless of the on / off state of the transmit / receive switch 200. Thus, by designing the capacitance of the first capacitor 401 within the amplifier 400 to the first signal line 500, the operation of the LNA 402 within the amplifier 400 can be stabilized. The capacitance of the first capacitor 401 in the amplifier 400 will be explained in detail later.

[0133] * "Variable attenuator" *

[0134] The variable attenuator 300 attenuates the received signal input from the vibrator 100 to the first signal line 500 via the transceiver switch 200, thereby achieving time gain control. Specifically, the following processing is performed: the received signal of the ultrasound waves reflected near the surface of the subject and input to the first signal line 500 at the beginning of reception is significantly attenuated, while the received signal of the ultrasound waves reflected from deeper parts of the subject over time is not attenuated.

[0135] The variable attenuator 300 is configured with a control terminal and a component having two terminals. In this embodiment, a P-channel MOSFET MP301a and an N-channel MOSFET MN301b are used as components and connected in parallel to form the variable attenuator 300.

[0136] One end of MP301a and MN301b, which are connected in parallel, is connected to the first signal line 500. Furthermore, the other end of MP301a and MN301b, which are connected in parallel, is connected to pad 41 on the 2D array IC 50. One terminal of the second capacitor 40 is connected to pad 41, and the other terminal of the second capacitor 40 is grounded.

[0137] Therefore, based on the attenuator control signal 30 input from the TGC control signal generator 20 to the control terminal (gate), the resistance value between the two terminals (source and drain) other than the control terminal changes. Specifically, the variable attenuator 300 can attenuate the signal of the first signal line 500 by combining its own variable control resistance value, the impedance of the oscillator 100, and the on-resistance of the transceiver switch 200.

[0138] Therefore, by changing the attenuator control signal 30 input to the variable attenuator 300 as time passes from the start of transmission (or reception), the attenuation rate of the variable attenuator 300 can be changed, thereby achieving time gain control.

[0139] In addition, such as Figure 1 As shown, the second capacitor (shared capacitor) 40 is connected to the variable attenuator 300 of all transceiver channels ECh11 to EchMN.

[0140] The second capacitor 40 can lower the lowest frequency of the frequency band attenuated by the variable attenuator 300 by increasing its capacitance. Therefore, the value of the electrostatic capacitance of the second capacitor 40 is pre-designed so that the desired frequency band can be attenuated by the variable attenuator 300.

[0141] The second capacitor 40 needs to have a sufficiently small impedance relative to the variable resistance of the variable attenuator 300 configured in the transceiver channels ECh11 to EChMN, the impedance of the vibrator 100, and the on-resistance of the transceiver switch 200. On the other hand, the first capacitor 401 forms a high-pass filter by combining with the input impedance of the LNA 402, and its blocking frequency is determined by the product of the large input impedance of the LNA 402 and the capacitance of the first capacitor 401. The impedance of the vibrator 100 is several thousand ohms, and the on-resistance of the transceiver switch 200 is tens to hundreds of ohms. In contrast, the large input impedance of the LNA 402 is several hundred to several megaohms. The receiving frequency band is determined by the combination of the impedances with large order-of-magnitude differences and the capacitance of the first capacitor 401, thus the second capacitor 40 becomes larger than the electrostatic capacitance of the first capacitor 401.

[0142] Furthermore, regarding the principle of time gain control achieved through the variable attenuator 300 and the electrostatic capacitance C of the second capacitor 40... 40 The design of the value will be explained in detail using formulas later.

[0143] In addition, the second capacitor 40 also functions to prevent the bias current Ibias of the transmit / receive switching switch 200 from flowing into the variable attenuator 300 via the first signal line 500.

[0144] *“TGC Control Signal Generator 20”*

[0145] The TGC control signal generator 20 generates the control signal for the variable attenuator 300. The TGC control signal generator 20 is a circuit that takes the TGC control signal 10 as input and generates the control signal input to the gates of MP301a and MN301b of the variable attenuator 300. The TGC control signal 10 can also be generated by an ultrasound diagnostic device, but it can also be generated by a 2D array IC 50.

[0146] like Figure 1 In this way, the TGC control signal generator 20 is installed in a region further out than the area on the 2D array IC 50 where multiple receiving circuits are installed.

[0147] Thus, in this embodiment, it is possible to implement both the variable attenuator 300 for TGC and the TGC control signal generator 20 that generates its control signal on the 2D array IC50.

[0148] The TGC control signal generator 20 is composed of a voltage-to-current converter VIC21, a current mirror CM21, an N-channel MOSFET MN21b, and a P-channel MOSFET MP21a. Detailed information about the circuit structure will be provided later.

[0149] *Amplifier 400*

[0150] Amplifier 400 includes a low-noise amplifier circuit (hereinafter, LNA) 402. Amplifier 400 amplifies the received signal attenuated by variable attenuator 300. In this embodiment, the variable attenuator 300 can attenuate signals with large amplitudes reflected near the surface of the subject, thus allowing the gain of LNA 402 to be set larger to match the small amplitude signals reflected from deep within the subject. This allows for a larger amplification of the received signal from deep within the subject, improving image accuracy.

[0151] A first capacitor 401 is connected in series on the first signal line 500 between LNA402 and the transmit / receive switch. That is, LNA402 receives the signal from the first signal line 500 via the first capacitor 401, amplifies it, and outputs it to the second signal line 502.

[0152] The first capacitor 401 maintains the difference between the potential of the first signal line 500, determined by the product of the resistor R205 and the bias current Ibias, and the potential suitable for the operation of the LNA 402, as a DC voltage. Therefore, the capacitance of the first capacitor 401 is pre-designed based on the difference between the potential suitable for the operation of the LNA 402 and the potential of the first signal line 500.

[0153] The first capacitor 401 is preferably inserted into the first signal line 500 between the variable attenuator 300 and the LNA 402, but the variable attenuator 300 can also be inserted between the first capacitor 401 and the LNA 402.

[0154] <Actions of each part during sending and receiving>

[0155] The operation of the circuitry on the 2D array IC50 of the probe during transmission and reception is explained.

[0156] The transmit and receive channels ECh11 to EChMN are pre-divided into multiple sub-channels (SCh).

[0157] *"send"*

[0158] During transmission, the transmission signal generated by the main body of the ultrasonic diagnostic device or the 2D array IC is split into circuits of all transceiver channels Ech within a sub-channel. The delay circuit 800 of each transceiver channel Ech assigns a given delay to the transmission signal. The transmission circuit 600 amplifies the delayed transmission signal and outputs it to the vibrator 100.

[0159] The vibrator 100 converts the transmitted signal after each given delay into ultrasonic waves and transmits them to the object under test. Thus, ultrasonic waves with a given transmission focus are transmitted.

[0160] During transmission, the transmit / receive switching switch 200 of the receiving circuit 700 switches the switching element (SW) 204 from the switching terminal 204a to the disconnecting terminal 204c side via the control signal VSW.

[0161] Therefore, the bias current Ibias flows through the bypass signal line 206 to the first signal line 500 side of the transceiver switch 200, and flows to ground through the resistor R205.

[0162] Therefore, the bias current Ibias does not flow to the floating voltage generation unit 203, and thus the gate-source voltage of MN201 and 202 becomes a voltage less than the threshold, and the transmit / receive switch 200 becomes open.

[0163] Therefore, the transmit / receive switch 200 can protect the downstream receiving circuit 700 from the large-amplitude transmitted signal output from the transmitting circuit 600 to the vibrator 100.

[0164] At this time, the bias current Ibias of the transmit / receive switch 200 is supplied to the first signal line 500 through the bypass signal line 206.

[0165] Therefore, the potential of the first signal line 500 during transmission becomes VDC, which is determined by the product of the bias current Ibias and the resistance value of resistor R205.

[0166] *"take over"*

[0167] The ultrasound waves sent to the subject propagate within the subject and are reflected by tissues within the subject, thus reaching the vibrator 100 again.

[0168] The vibrator 100 receives the reflected ultrasonic waves, converts them into electrical signals, and outputs the received signal.

[0169] The transmit / receive switch 200 switches the bias current Ibias using SW according to the control signal VSW. During reception, the bias current Ibias flows to the floating voltage generation unit 203, generating a gate-source voltage that turns on MN201 and 202, which are high-voltage Nch MOSFETs. As a result, the transmit / receive switch 200 is turned on.

[0170] Therefore, the received signal output from the vibrator 100 is applied to the first signal line 500, and the vibrator vibrates around the potential of the first signal line 500.

[0171] The bias current Ibias, which passes through the floating voltage generation unit 203, flows to ground through MN202 and resistor R205.

[0172] Therefore, the potential of the first signal line 500 during reception becomes VDC determined by the product of the bias current Ibias that causes the floating voltage generation unit 203 to operate and the resistance value of the resistor R205.

[0173] The received signal output from the vibrator 100 vibrates in the first signal line 500, centered on the potential VDC of the first signal line 500.

[0174] Thus, in this embodiment, the bias current Ibias is grounded via resistor R205 when the transmit / receive switch 200 is switched to open and closed during transmission and reception, respectively. Therefore, the potential of the first signal line 500 does not change due to the switching between transmission and reception, and can be kept constant.

[0175] The received signal of the first signal line 500 is input to the variable attenuator 300.

[0176] The variable attenuator 300 attenuates the electrical signal according to the level of the attenuator control signal 30.

[0177] The attenuator control signal 30 is a pair of signals generated by the TGC control signal generator 20 based on the TGC control signal 10, and is input to the control terminal (gate) of the variable attenuator 300.

[0178] For example, Figure 3 As shown, the TGC control signal 10 is a gradually rising, sloping signal that begins when the time gain control (TGC) starts.

[0179] In the TGC control signal generator 20, the TGC control signal 10 is converted into current by the voltage-to-current converter VIC 21. Specifically, the voltage-to-current converter VIC 21 converts the signal into output currents 22 and 23, which gradually decrease from the start of TGC.

[0180] Output current 23 flows into MN21b, which is an N-channel MOSFET. Output current 22 becomes output current 22', whose polarity has been changed by current mirror CM21, and flows into MP21a, which is a P-channel MOSFET. The gate potentials of MP21a and MN21b become the attenuator control signal 30.

[0181] The generated attenuator control signal 30 is input to the control terminals (gates) of the variable attenuator 300, which is a P-channel MOSFET MP301a and an N-channel MOSFET MN301b.

[0182] Therefore, the gate-source voltage of MN301b gradually decreases from the start of TGC, and thus the drain-source resistance RMN gradually increases. Similarly, the source-gate voltage of MP301a gradually decreases from the start of TGC, and thus the drain-source resistance RMP also gradually increases.

[0183] The received signal of the first signal line 500 at the beginning of the time gain control (TGC) when the resistance of MP301a and MN301b is small (when receiving signals from near the body surface), the attenuation rate decreases as the resistance of MP301a and MN301b gradually increases (as the depth increases).

[0184] The attenuated received signal is input to amplifier 400.

[0185] Amplifier 400's LNA402 amplifies the received signal to minimize the impact of signal degradation on the noise ratio. LNA402 operates via power supply VDD2. While also dependent on circuit configuration, LNA402 is configured to amplify a signal that oscillates around a predetermined bias voltage VDCIN between the power supply VDD2 and ground.

[0186] The potential (bias voltage) VDC of the first signal line 500, as shown above, is determined by the bias current Ibias and the resistance value of resistor R205, and is different from the bias voltage VDCIN of LNA402. Therefore, a first capacitor 401 is configured in front of LNA402, so that the bias voltage of terminal 501 of the first capacitor 401 on the LNA402 side is consistent with the bias voltage VDCIN of LNA402, and is connected to LNA402.

[0187] <Principle of TGC Implementation by Variable Attenuator 300>

[0188] The principle of time gain control achieved by the variable attenuator 300 will be explained in further detail using formulas.

[0189] If the impedance of vibrator 100 is set to Z TD Set the on-resistance of the transmit / receive switch 200 to R. TRSWON Set the drain-source resistance of MN301b and MP301a of the variable attenuator 300 to R respectively. DSN301b R DSP301a Let the capacitance of the second capacitor 40 be C. 40 Let the impedance of the second capacitor 40 be Z. 40 Set the resistance of the variable attenuator 300 to R. ATT The current I flowing in the variable attenuator 300 is... ATTUsing equations (1) to (2), we can find the answer as in equation (3).

[0190] Z 40 =j / (2πfxC) 40 )……(1)

[0191] R ATT =R DSN301b ×R DSPa301 / (R DSN301b +R DsP301a )……(2)

[0192] I ATT =|(R) ATT +Z 40 ) / (Z TD +R TRSWON +R ATT +Z 40 )|……(3)

[0193] In equation (1), f is the frequency and j is the imaginary unit (i.e., √(-1)).

[0194] In particular, within the desired frequency band of the received signal, the impedance Z of the second capacitor 40 40 The absolute value of the variable attenuator 300 is compared to the resistance R. ATT Sufficiently small (|Z) 40 |<<R ATT When ), the current I flowing in the variable attenuator 300 ATT It is represented by equation (4).

[0195]

[0196] If the input impedance of amplifier 400 is sufficiently large, then the received signal, which is converted from ultrasonic waves to electrical signals by vibrator 100, will...

[0197] |20×log(I ATT )|[dB]

[0198] The attenuation is reduced and input to amplifier 400.

[0199] Here, the drain-source resistance R of the variable attenuator 300 MN301b and MP301a is... DSN301b and R DSP301a It is a function of the attenuator control signal 30. The attenuator control signal 30 is a function of the TGC control signal 10, such as... Figure 3 As shown, the TGC control signal 10 is a signal that rises along with the time. Therefore, as... Figure 4As shown, the attenuation of the signal amplitude input to amplifier 400 decreases along with time. Therefore, the attenuation is maximized at the start of time gain control (from the received signal near the body surface), and the attenuation decreases over time, thus reducing the signal's decay. In other words, time gain control of the receiving circuit is possible.

[0200] <The electrostatic capacitance C of the second capacitor 40> 40 Value design >

[0201] The electrostatic capacitance C of the second capacitor 40 40 The design of the value is explained using a formula.

[0202] If the resistor R of the variable attenuator 300, which can be set by the attenuator control signal 30, is... ATT Let the minimum and maximum values ​​be R respectively. ATTmin R ATTmax The current I flowing in the variable attenuator 300 ATT The minimum value (setting the receive gain to the minimum value) and the maximum value (setting the receive gain to the maximum value) are respectively set to I. ATTmax I ATTmin , then I ATTmax I ATTmin This is represented by equations (5) and (6).

[0203] I ATTmax =|(R) ATTmin +Z 40 ) / (Z TD +R TRSWON +R ATTmin +Z 40 )|……(5)

[0204] I ATTmin =|(R) ATTmax +Z 40 ) / (Z TD +R TRSWON +R ATTmax +Z 40 )|……(6)

[0205] Therefore, the current I flowing in the variable attenuator 300 ATT The control range is the range of equation (7).

[0206] I ATTmax ≤I ATT ≤I ATTmin ……(7)

[0207] exist Figure 4 The frequency-to-attenuation characteristics of the variable attenuator 300 are shown in the figure. Figure 4As shown, at the start of TGC, the variable attenuator 300 begins to attenuate at frequency f1, and the attenuation becomes constant in the frequency band above frequency f2. Frequency f1 and frequency f2 are expressed as in equations (8) and (9).

[0208] Frequency f1 = 1 / (2πC) 40 ) / (Z TD +R TRSWON +R ATTmin )……(8)

[0209] Frequency f2 = 1 / (2πC) 40 ×R ATTmin )……(9)

[0210] Therefore, the capacitance C of the second capacitor 40 is designed. 40 R TRSWON and R ATTmin This is such that at least the frequency band of the received signal used to generate the ultrasonic image is included in the high-frequency band compared to the frequency f2 with a fixed attenuation. For example, this can be achieved by adjusting the capacitance C of the second capacitor 40. 40 Adjustments are made to more easily make the bandwidth of the received signal used in the generation of ultrasound images greater than frequency f2.

[0211] By adjusting the resistance R of the variable attenuator 300 ATT The impedance Z of the second capacitor is 40. 40 Sufficiently small (R) ATT <<Z 40 This allows for more efficient use of the variable range of the drain-source resistance of MN301 and PN301, which are used as voltage-controlled variable resistors.

[0212] In this embodiment, the second capacitor 40 is configured as a different element from the 2D array IC 50, and the two are connected via pad 41. However, it can also be mounted within the 2D array IC 50. The current I flowing in the variable attenuator 300... ATT When the control range can ensure that the area of ​​the second capacitor 40 can be formed to meet the usage range, it can also be mounted in the same die area as the M×N transceiver circuits mounted on the 2D array IC50 and their peripheral block circuits.

[0213] As described above, according to this embodiment 1, the M×N transceiver channels ECh11~EchMN are mounted in a matrix on the same 2D array IC50. Only one TGC control signal generator 20 needs to be configured with a high degree of freedom around it, thus suppressing the increase in the circuit size mounted on the 2D array IC50.

[0214] Furthermore, according to this embodiment, each of the thousands to 10,000 elements of the vibrator 100 can be connected to a receiving circuit 700, each having an independent variable gain function with small deviation.

[0215] Moreover, it is possible to suppress circuit size and power consumption and perform time gain control by configuring them into multiple 2D arrays.

[0216] Therefore, it is possible to provide an ultrasound diagnostic device with a 2D array probe that improves the SNR of diagnostic images both near the body surface and deep within the body.

[0217] Furthermore, the 2D array IC50 installed within the probe can generate an attenuator control signal 30 that automatically controls the gain of the variable attenuator 300. This allows for simultaneous gain control of multiple amplifiers 400. Consequently, gain deviations in multiple transmit and receive channels Ech can be suppressed, enabling the construction of a TGC circuit suitable for the 2D array IC50.

[0218] Furthermore, by configuring the bypass signal line 206 so that the bias current Ibias also flows through the resistor R205 when the transmit / receive switch 200 is off, the potential (bias voltage) VDC of the first signal line 500 can be fixed whether the transmit / receive switch 200 is on or off. This allows the bias potential of the received signal input to the LNA402 of the amplifier 400 to be fixed, thus stabilizing the amplification process of the LNA402.

[0219] <<<Implementation Method 2>>>

[0220] For the probe used in the ultrasound diagnostic device of Embodiment 2, Figure 5 Let me explain. Figure 5 This is a schematic diagram showing the circuitry of a 2D array IC50 containing multiple transceiver circuits within the probe.

[0221] The 2D array IC50 in Embodiment 2 is similar to that in Embodiment 1, with transceiver channels ECh11 to EchMN arranged in two dimensions. However, as a shared capacitor, a third capacitor 42 is added in addition to the second capacitor 40. The transceiver channel Ech, which is far from the second capacitor 40 and the pad 41, is connected to the pad 43 connected to the third capacitor 42. That is, the transceiver channels ECh11 to EChMN are connected to the pads that are closer in position among the two or more pads 41 and 43, so that the length of the wiring connected to the second or third capacitor 40 or 42 is less than a given value. As a result, the wiring 503 connecting the transceiver channel Ech to the second capacitor 40 or the third capacitor 42 is shortened, and the wiring resistance is applied to the resistance of the variable attenuator 300 to suppress attenuation changes.

[0222] This will be further explained using formulas. Additionally, in Figure 5 In the middle, to and Figures 1-4 The same constituent elements are given the same symbols, and the explanation is omitted.

[0223] exist Figure 5 In the middle, the transmit / receive channel ECh closest to the second capacitor 40 will be used. _Nearest The wiring resistance of wiring 503 up to the second capacitor 40 is expressed as RM. _Nearest The transmit / receive channel ECh, which is furthest from the second capacitor 40, will be used. _Farest The wiring resistance of wiring 503 up to the second capacitor 40 is expressed as RM. _Farest .

[0224] The 2D array IC50 has M×N such transceiver circuits installed, thus the transceiver channel ECh closest to the second capacitor 40 _Nearest and the furthest from the transmit / receive channel ECh _Farest In the middle, the cause is the wiring resistance RM _Nearest and wiring resistance RM _Farest The difference, thus affecting the current I flowing in the variable attenuator 300. ATT This will cause differences. At this point, differences will occur in the transmit / receive channel ECh. _Nearest and transmit / receive channel ECh _Farest The current I flowing in the variable attenuator 300 ATT Let the maximum and minimum values ​​be I respectively. ATT_Nearest_max I AIT_Nearest_min and I ATT_Farest_max I ATT_Farest_min For them, substitute the wiring resistance R into equations (5) and (6). M_Nearest R M_Farest , respectively represented as equations (10) to (13).

[0225] I ATT_Nearest_max

[0226] =|(R) ATTmin +Z 40 +R M_Nearest ) / (Z TD +R TRSWON +R ATTmin +Z 40 +R M_Nearest )|……(10)

[0227] I ATT_Nearest_min

[0228] =|(R) ATTmax +Z 40 +R M_Nearest ) / (ZTD +R TRSWON +R ATTmax +Z 40 +R M_Nearest )|……(11)

[0229] I ATT_Farest_max

[0230] =|(R) ATTmin +Z 40 +R M_Farest ) / (Z TD +R TRSWON +R ATTmin +Z 40 +R M_Farest )|……(12)

[0231] I ATT_Farest_min

[0232] =|(R) ATTmax +Z 40 +R M_Farest ) / (Z TD +R TRSWON +R ATTmax +Z 40 +R M_Farest )|……(13)

[0233] In addition, in equations (10) to (13), R ATTmin R ATTmax These are the resistors R of the variable attenuator 300. ATT The minimum and maximum values ​​of Z 40 The impedance Z of the second capacitor 40 is 40 Z TD It is the impedance of vibrator 100, R TRSWON It is the on-resistance of the transmit / receive switch 200.

[0234] Therefore, the current I flowing in the variable attenuator 300 ATT_Nearest I ATT_Farest The control range is the range of equations (14) and (15).

[0235] I ATT_Nearest_max ≤I ATT_Nearest ≤I ATT_Nearest_min ……(14)

[0236] I ATT_Farest_max ≤I ATT_Farest ≤I ATT_Farest_min ……(15)

[0237] At the end of time gain control, a large receiving gain is required for the variable attenuator 300, therefore the resistance R of the variable attenuator 300...ATTmax Satisfy equation (16).

[0238] R ATTmax >>Z TD +R TRSWON +Z 40 + Wiring resistance……(16)

[0239] In this case, the transmit / receive channel ECh closest to the second capacitor 40 _Nearest The current I flowing in the variable attenuator 300 ATT Minimum current I ATT_Nearest_min and the transmit / receive channel ECh furthest from the second capacitor 40 _Farest The current I flowing in the variable attenuator 300 ATT Minimum current I ATT_Farest_min As in equation (17), they can be approximated as almost equal.

[0240]

[0241] The transmit / receive channel ECh closest to the second capacitor 40 _Nearest The attenuation in the variable attenuator 300 is related to the transmit / receive channel ECh furthest from the second capacitor 40. _Farest The difference in attenuation in the variable attenuator 300 is represented by equation (18).

[0242] |20log(I ATT_Nearest_max / I ATT_Farest_max )|[dB]……(18)

[0243] Therefore, when the difference in attenuation expressed by equation (18) is set to a standard of less than 1 dB, a small signal attenuation occurs in the transceiver channel Ech located far from the second capacitor 40, which does not meet the standard of less than 1 dB.

[0244] In this embodiment, such as Figure 5 As shown, due to the addition of the third capacitor 42 and pad 43 to the transceiver channel ECh furthest from the second capacitor 40 _Farest The signal attenuation of the variable attenuator 300 is suppressed because it is located nearby.

[0245] Therefore, the variable attenuators 300 of multiple (M×N) transmit and receive channels Ech can suppress deviations in signal attenuation and achieve uniform time gain control. This enables the provision of an ultrasound diagnostic apparatus equipped with a 2D array probe that improves the SNR of both near-field and deep diagnostic images.

[0246] <<<Implementation Method 3>>>

[0247] For the probe used in the ultrasonic diagnostic device of Embodiment 3, Figure 6 Let me explain. Figure 6 This is a detailed diagram of the ECh transceiver channel in implementation method 3. Figure 6 In the middle, to and Figure 2 Same constituent element labeling and Figure 2 Same symbols, with explanations omitted.

[0248] As described in Embodiment 1, the received signal, converted from ultrasonic waves to an electrical signal by the vibrator 100, vibrates around the potential (bias voltage) VDC of the first signal line 500. Potential VDC is close to ground. Because the signal vibrates with a large amplitude around this potential, the drain potential of the n-channel MOSFET MN301b sometimes drops compared to the source potential. At this time, if the back gate 302b is connected to ground, current flows from the back gate 302b to the drain, resulting in signal distortion on the first signal line 500.

[0249] Therefore, in Embodiment 3, by connecting the back gate 302b of MN301b to a power supply VSS2 with a potential lower than ground, the phenomenon of current flowing from the back gate 302b to the drain is suppressed. This prevents signal distortion of the first signal line 500.

[0250] Similarly, the back gate 302a of MP301a, which is a P-channel MOSFET, is connected to a power supply VDD2 with a potential higher than ground.

[0251] Furthermore, the back gate 24b of MN21b, which is an N-channel MOSFET, of the TGC control signal generator 20 is connected to the power supply VSS2. Additionally, the back gate 24a of MP21a, which is a P-channel MOSFET, is connected to the power supply VDD2.

[0252] Figure 7 (a) and (b) show the input of a 2.5MHz sine wave signal to... Figure 6 The spectrum of the output signal when the variable attenuator is 300. Figure 7 (a) is as follows Figure 6 Thus, a variable attenuator 300 is connected by connecting the back gate 302b of MN301b to power supply VSS2 and the back gate 302a of MP301a to power supply VDDS. Figure 7 (b) is a variable attenuator 300 that connects the back grids 302a and 302b to ground.

[0253] exist Figure 7 In the spectra of (a) and (b), the leftmost peak is the fundamental frequency (in this case, a 2.5Hz sine wave), and the peak in the middle is the second harmonic. It can be confirmed that... Figure 7 (a) ratio Figure 7 (b) is better at suppressing second-order harmonic levels.

[0254] The structure and function / effect of probes other than those mentioned above are the same as those in Implementation Method 1.

[0255] <<<Implementation Method 4>>>

[0256] Figure 8 This is a structural diagram of the ultrasonic diagnostic device in Implementation Method 4.

[0257] The ultrasound diagnostic device consists of a main unit (US90), a display (US80), and an operation panel (US70).

[0258] The main unit US90 is equipped with connector boxes US30 and US31 for connecting probes and a detector selector US40.

[0259] In addition, the main unit US90 is equipped with a transceiver switch US320, amplifiers US121 and US120, an analog-to-digital converter US54, and a signal processing circuit US60. Casters US1000 and US1001 are located on the bottom of the main unit US90, allowing the ultrasonic diagnostic device to move freely on the ground.

[0260] Amplifier US121 amplifies the transmitted signal. Transceiver switch US320 prevents the transmitted signal from entering the receiving system. Amplifier US120 amplifies the received signals from the sub-channels received by probes US10 and US11.

[0261] The signal processing circuit US60 is a logic circuit that receives the output signal of amplifier US120 as a digital signal via analog-to-digital converter US54 and performs signal processing to generate an ultrasonic image. During transmission, the signal processing circuit US60 inputs the processed transmission signal to amplifier US121 via digital-to-analog converter US51, and transmits it to the 2D array probes US10 and US11 via detector selector US40, connector boxes US30 and US31, and cables US20 and US21.

[0262] Probes US10 and US11 are connected to connector boxes US30 and US31 via cables US20 and US21. Detector selector US40 selectively connects either probe US10 or US11 to transceiver switch US320.

[0263] Each of the embodiments 1 to 3, namely a 2D array IC50, is installed in probes US10 and US11. Furthermore, matching layers US200 and US201 and acoustic lenses US210 and US211 are also disposed in probes US10 and US11. Matching layers US200 and US201 match the acoustic impedance of the vibrator 100 of the 2D array with that of the biological body. Acoustic lens US210 converges the ultrasonic beam.

[0264] In addition, Figure 8 The main body of the ultrasound diagnostic device US90 has two connector boxes US30 and US31, which connect to two 2D array probes US10 and US11, but the number of probes connected is not limited to two. Furthermore, conventional 1D array probes can also be connected to connector boxes US30 and US31. Additionally, connector box terminals for connecting special probes such as those for Doppler ultrasound can also be provided.

[0265] The main unit US90, including the device for observing specific parts of the patient's body, is operated via the control panel US70. Furthermore, the main unit US90 features various diagnostic modes, which are also switched via the control panel US70. These diagnostic modes include B (Brightness), PW (Pulsed Wave Doppler), CFM (Color Flow Mapping), and STCW (Steerable CW Doppler).

[0266] Mode B is a mode that establishes a correspondence between the received amplitude intensity and brightness of ultrasound waves reflected from tissues for display.

[0267] PW mode involves repeatedly transmitting ultrasound waves toward a specific depth and measuring the frequency shift of the signal reflected from that location with each repetition to determine blood flow velocity. In PW mode, blood flow velocity at a specific location can be determined and displayed overlaid with a B-mode image.

[0268] CFM, also known as Color Doppler, is a mode that visualizes blood flow velocity by calculating the autocorrelation of the received signal at each ultrasound transmission. In CFM mode, the average velocity of multiple points on the ultrasound receiving beam can be determined, and this can be used to detect backflow, etc.

[0269] STCW mode is also a mode for measuring blood flow velocity, but it is suitable for measuring fast blood flow velocities.

[0270] The signal processing circuit US60 processes the signal from the analog-to-digital converter US54 to generate diagnostic images for the various modes described above. These images are displayed on the monitor US80.

[0271] The TGC circuit in this embodiment is not limited to a 2D array IC, but can also be used to receive ultrasonic signals implemented by a conventional ultrasonic probe such as a 1D probe. Furthermore, the same TGC function can be achieved even if it is installed on the device side instead of the probe.

[0272] The embodiments have been described above, but the present invention is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above have been described in detail for the purpose of making the present invention easy to understand, and are not limited to having all the structures described.

Claims

1. A probe connected to an ultrasonic diagnostic device, wherein the probe transmits ultrasonic waves to the diagnostic site and receives a received signal as a reflected wave, characterized in that... The probe has multiple receiving circuits. Each of the aforementioned receiving circuits includes: The vibrator converts the received signal into an electrical signal at ground level and outputs it as the first output signal; A transmit / receive switch is connected to the first signal line to switch whether to output the first output signal from the vibrator to the first signal line. A variable attenuator has a control terminal and two terminals, and changes the resistance value between the two terminals other than the control terminal based on a control signal input to the control terminal; The first capacitor is connected to the first signal line; and The amplifier includes at least an amplification circuit that amplifies the electrical signal from the first signal line and outputs it to the second signal line, wherein the input terminal of the amplification circuit is connected to the first capacitor. When the transmit / receive switch is open, it outputs a bias potential to the first signal line. One of the two terminals of the variable attenuator other than the control terminal is connected to the first signal line, and the other terminal is grounded via a second capacitor, which is different from the first capacitor.

2. The probe according to claim 1, characterized in that, The probe has an integrated circuit and one or more common capacitors disposed outside the integrated circuit. The integrated circuit includes multiple receiving circuits. The shared capacitor is connected to the plurality of receiving circuits and operates as the second capacitor of the plurality of receiving circuits. The shared capacitor is located on the outside of the integrated circuit.

3. The probe according to claim 2, characterized in that, The electrostatic capacitance of the shared capacitor is greater than that of the first capacitor.

4. The probe according to claim 1, characterized in that, The off-time bias potential output by the transceiver switch to the first signal line when the switch is off is the same as the on-time bias potential output by the transceiver switch to the first signal line when the switch is on.

5. The probe according to claim 1, characterized in that, The transmit / receive switch includes one or more MOSFETs and has the function of allowing current to flow on the side of the first capacitor to determine the bias potential of the first signal line without passing through the high-voltage MOSFET when the switch is open.

6. The probe according to claim 2, characterized in that, The probe has one or more control signal generators that output the control signals to multiple receiving circuits respectively. The control signal generator is installed in the integrated circuit in a region that is further outward than the region where the plurality of receiving circuits are installed.

7. The probe according to claim 2, characterized in that, There are two or more shared capacitors, which are connected to multiple receiving circuits via two or more pads disposed on the integrated circuit. The receiving circuit is connected to the pad closest to one of two or more pads, such that the length of the wiring connected to the common capacitor is below a given value.

8. The probe according to claim 1, characterized in that, The variable attenuator includes one or more MOSFETs, each MOSFET having the control terminal and the two terminals. The back gate of the MOSFET is connected to a power supply that is not grounded.

9. A probe connected to an ultrasonic diagnostic device, wherein the probe transmits ultrasonic waves to a target area and receives ultrasonic signals as reflected waves, characterized in that... The probe has: Multiple vibrators arranged in a row; The transmitting circuit outputs signals to the multiple vibrators respectively; And multiple receiving circuits, each connected to one of the vibrators. The plurality of receiving circuits each include: a transmit / receive switch; an amplifier circuit; a first signal line connecting the transmit / receive switch and the amplifier circuit; and a variable attenuator connected midway along the first signal line. The vibrator converts the ultrasonic signal into an electrical signal and outputs it as the first output signal to the transceiver switch. The transmit / receive switch toggles whether the first output signal from the vibrator is output to the first signal line. The variable attenuator includes one or more components, each component having a control terminal and two terminals, and is a component whose resistance value between the two terminals (excluding the control terminal) changes according to a control signal input to the control terminal, and one of the two terminals of the component is connected to the first signal line.

10. The probe according to claim 9, characterized in that, As one or more of the elements of the variable attenuator, there are N-channel MOSFETs and P-channel MOSFETs connected in parallel. One terminal side of the parallel connection is connected to the first signal line, and the other terminal side is grounded via the second capacitor.

11. The probe according to claim 9, characterized in that, The transceiver switching switch includes one or more MOSFETs for transceiver switching, a floating voltage generation unit, a switching element, a bypass signal line, and a resistor with one end connected to the first signal line. The transmit / receive switch uses one terminal of the source and drain of the MOSFET to connect to the vibrator, and the other terminal to connect to the first signal line. The floating voltage generation unit generates a voltage applied between the gate and source of the MOSFET used for the transmit / receive switching. One end of the resistor is connected to the first signal line, and the other end is grounded. The switching element has a switching terminal, an on terminal, and an off terminal connected to a bias current source. The on terminal is connected to the floating voltage generating unit and supplies bias current to the floating voltage generating unit when it is on. The off terminal is connected to the first signal line through the bypass signal line and allows the bias current to flow into the resistor through the first signal line when it is off.

12. The probe according to claim 9, characterized in that, A first capacitor is inserted in series in the first signal line between the amplifier circuit and the transmit / receive switch.

13. An ultrasonic diagnostic device, characterized in that, have: The probe according to any one of claims 1 to 12; and The processing device processes the signals received from the probe.

Images