JP4680555B2 - Ultrasonic diagnostic apparatus and semiconductor integrated circuit thereof - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus suitable for miniaturization and high frequency and a semiconductor integrated circuit of a transmission amplifier circuit thereof.

  A transmission signal of the ultrasonic diagnostic apparatus is generated by a DAC (Digital Analog Converter) and amplified by a transmission amplifier circuit. There is a desire to apply a transmission signal in a wide voltage range from about 150 V to about 10 V to the ultrasonic transducer depending on the type of diagnostic mode and the type of ultrasonic transducer incorporated in the probe. To apply a low-voltage-amplitude transmission when the voltage gain of the transmission amplifier circuit is fixed, a signal that has been amplified using only the output voltage of the DAC is used as the transmission signal. . For this reason, there has been a problem that it is possible to generate only a transmission signal having an accuracy of about one digit lower than the accuracy of the original DAC.

  As a countermeasure against this, as described in Patent Document 1, a method is proposed in which a pulse wave amplifier circuit used as a transmission amplifier and a continuous wave amplifier circuit are connected in parallel, and the amplifier circuit is selectively used in accordance with the purpose of diagnosis. Yes. In addition, as a method of selecting an amplifier circuit to be operated from among amplifier circuits for transmission amplifiers arranged in parallel, it is disclosed that output transistors of a transmission amplifier circuit that are not used are cut off.

  On the other hand, Patent Document 2 also proposes a method of applying a voltage to an ultrasonic transducer by changing a power supply voltage of a transmission amplifier circuit. The transmission amplifier circuit in this case is a switch circuit that outputs a high voltage or a low voltage depending on the value of the input voltage.

JP 2002-65672 A JP 2001-258889 A

  In the prior art described above, the device described in Patent Document 1 has a problem in miniaturization and cost reduction because the number of elements of the transmission amplifier circuit increases. In addition, since the input signals for transmission are input to the two amplifier circuits, the preceding circuit portion operates even in the amplifier circuit that shuts off the output transistor. Therefore, a plurality of transmission amplifier circuits are provided in the semiconductor integrated circuit. When they are formed on the same chip, interference between the transmission amplifier circuits becomes a problem.

  The device described in Patent Document 2 is not a linear amplifier having a fixed voltage gain with respect to an input voltage signal. In addition, in order to improve the resolution of the ultrasonic beam, it is impossible to perform signal processing that slightly changes the voltage applied to the ultrasonic transducer array. In other words, the entire beam cannot be narrowed by giving a free weight to the amplitude of the waveform transmitted from the ultrasonic transducer array to the subject. Alternatively, transmission / reception signal processing with low noise could not be performed by freely changing the voltage amplitude of each pulse of the burst wave.

  The object of the present invention is to solve the above-mentioned problems of the prior art, and the performance such as the resolution of the ultrasonic transducer even when the voltage amplitude of the transmitted signal is changed in accordance with the change of the diagnostic mode or probe of the ultrasonic diagnostic apparatus. Is to provide an ultrasonic diagnostic apparatus capable of maintaining the optimal conditions. Another object of the present invention is to provide a semiconductor integrated circuit in which the ultrasonic wave transmission circuit is configured as a small wave transmission amplifier circuit.

  The present invention relates to a high-voltage, high-band transmission amplifier circuit, and in particular, the output voltage is filled to the full power supply voltage without saturating the output waveform in both the high and low output voltage amplitude modes. An ultrasonic diagnostic apparatus including a linear amplifier type transmission amplifier circuit capable of outputting is provided.

  By using the linear amplifier type, in the diagnosis mode where the maximum amplitude of the transmission signal of the ultrasonic diagnostic apparatus is high, the power supply voltage of the transmission amplifier circuit is increased, the voltage gain is also increased, and the maximum amplitude of the transmission signal is increased. In the low diagnostic mode, the power supply voltage of the transmission amplifier circuit is lowered and the voltage gain is also lowered.

  Furthermore, the transmission amplifier circuit configured as a linear amplifier type is compactly made by providing a relay point between the ultrasonic diagnostic equipment body and the probe, and the transmission amplifier circuit and transmission / reception separation circuit are made into semiconductor integrated circuits. It is characterized by providing.

  The ultrasonic diagnostic apparatus of the present invention uses a high-voltage broadband transmission amplifier circuit that can change the power supply voltage and voltage gain of the transmission amplifier circuit depending on the type of diagnostic mode and the type of ultrasonic transducer built in the probe. Therefore, there is an effect that it is possible to transmit a high-accuracy transmission output signal that maximizes the accuracy of the DAC.

  Further, since the load on the transmission amplifier circuit is lightened, it is easy to increase the frequency of the transmission amplifier circuit, and the output transistor is also small, so that there is an advantage that the transmission amplifier circuit can be easily integrated into an IC. Furthermore, there is an advantage that the operability of the probe of the ultrasonic diagnostic apparatus is not hindered.

  In the ultrasonic diagnostic apparatus of the present invention, when the type of diagnostic mode or the type of ultrasonic transducer incorporated in the probe changes, not only the high-voltage power supply voltage of the transmission amplifier circuit is changed, but also the transmission amplifier circuit The voltage gain of is also optimized. As a result, a linear transmission amplifier circuit that maximizes the accuracy of the DAC that generates the transmission was realized, and the accuracy of the ultrasonic diagnostic apparatus was improved.

  In addition, a relay point is provided between the main body of the ultrasonic diagnostic apparatus and the probe, and a transmission amplifier circuit and a transmission / reception separation circuit are provided as semiconductor integrated circuits, thereby reducing the size and cost of the transmission amplifier circuit. Made it easier. Furthermore, the operability of the probe of the ultrasonic diagnostic apparatus has been improved.

  Further, in the transmission amplifier circuit of the present invention, by using SOI (Silicon On Insulator) device technology which is an insulator separation, a linear amplifier circuit with a high breakdown voltage and a wide band and a small interference noise between elements is realized.

  FIG. 1 is a block circuit diagram of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. The body 3 of the ultrasonic diagnostic apparatus includes a DAC (Digital Analog Converter) 8 that generates a transmission signal and a reception amplifier circuit 9 that amplifies the reception signal to generate a diagnostic image. The relay point 2 is arranged between the probe housing 1 in which the ultrasonic transducer 34 is built and the main body 3 of the ultrasonic diagnostic apparatus. The relay point 2 includes not only the transmission amplifier circuit 21 and the transmission / reception separation circuit 11 but also the pre-stage reception amplifier circuit 12, the coupling capacitors 25 and 24, and the impedance 32. 47 is an input terminal of the transmission amplifier circuit 21, and 48 is an output terminal. In this embodiment, the pre-stage receiving amplifier circuit 12 and the receiving amplifier circuit 9 are used to amplify the received signal, but only the receiving amplifier circuit 9 is used without using the pre-stage receiving amplifier circuit 12. It may be amplified.

The reference voltage 7 is ground. The high-voltage power supplies (for high-voltage transmission) 15 and 16 are about 60V, and the high-voltage power supplies (for low-voltage transmission) 17 and 18 are lower than those for high-voltage transmission, for example, about 10V. These power supplies are power supplies used for the output transistors of the transmission amplifier circuit 21, and the voltage values of the power supply voltage terminals 40 and 41 of the transmission amplifier circuit 21 can be changed by the switches 13 and 14 depending on the diagnosis mode and the type of probe. it can.
The voltage gain of the transmission amplifier circuit 21 is determined by the impedances 27 and 28 constituting the feedback circuit 22. In order to change the voltage gain by changing the ratio of the impedances 27 and 28, the feedback circuit control signal 33 for the transmission amplifier is used. Used.

  The transmission signal is generated by the DAC 8 and the power is amplified to about 1 to 10 times by the front-stage transmission amplifier circuit 23 (when the voltage gain is 1, the front-stage transmission amplifier circuit 23 functions as a buffer circuit that amplifies the current). To do. Thereafter, the voltage is further amplified by about 1 to 100 times in accordance with the output voltage level by the transmission amplifier circuit 21 via the cables 6 and 4. In this embodiment, the pre-stage transmission amplifier circuit 23 and the transmission amplifier circuit 21 are used to amplify the transmission signal. However, the amplification may be performed using only the transmission amplifier circuit 21.

  When sending a transmission signal, the switch circuit 42 is turned on and the switch circuit 43 is turned off. When receiving a received signal, the switch circuit 42 is turned off and the switch circuit 43 is turned on. In addition, the transmission amplifier circuit 21 has a switch circuit 26 (controlled by the enable signal 30) for controlling whether or not to pass an input signal to the amplifier, and whether the output transistor of the transmission amplifier circuit 21 is operable. An enable signal 29 is provided for controlling whether or not. The transmission / reception separating circuit 11 cuts off the high-voltage transmission voltage and passes the reception signal returned from the transducer 34 or disables the disable signal 31 for controlling not only the transmission signal but also the reception signal. Is provided. As the transmission / reception separating circuit 11, a circuit disclosed in Japanese Patent Laid-Open No. 10-328186 can be used.

  In FIG. 1, only one set of the DAC 8, the transmission amplifier circuit 21, the transmission / reception separation circuit 11, and the reception amplifier circuit 9 corresponding to one transducer 34 is shown. Actually, a plurality of transducers are arranged in an array in the probe housing 1, and the DAC 8, the transmission amplifier circuit 21, the transmission / reception separation circuit 11, and the reception amplifier circuit 9 corresponding to each transducer are arranged. Are provided in the relay point 2 and the main body 3 of the ultrasonic diagnostic apparatus.

  The first feature of the present embodiment is that high-voltage transmission power supplies 15 and 16 for obtaining a maximum amplitude of about ± 60 V as a high-voltage power supply of the transmission amplifier circuit, and a low-voltage transmission for obtaining a maximum amplitude of about ± 10 V. The power sources 17 and 18 can be switched by the switch circuits 13 and 14. Further, the transmission amplifier circuit 21 is a linear amplifier circuit, and the voltage gain is determined by the ratio of the impedances 27 and 28 of the feedback circuit 22. According to the feedback circuit control signal 33 for the transmission amplifier, the voltage gain of the transmission amplifier circuit is increased when the high-voltage transmission power supply voltage is high, and the voltage gain of the transmission amplifier circuit when the high-voltage transmission power supply voltage is low. Control low.

  FIG. 2 shows the characteristics of the transmission amplifier circuit. The amplification characteristic is linear, an output signal that is substantially proportional to the input signal can be transmitted, and the voltage gain can also be changed when the power supply voltage needs to be changed by switching the diagnostic mode or replacing the probe.

  In this embodiment, when the voltage level of the transmission signal is changed depending on the type of diagnostic mode and the type of ultrasonic transducer incorporated in the probe, not only the power supply voltage of the transmission amplifier circuit 21 but also the voltage gain is changed. Therefore, there is an effect that a high-accuracy transmission signal that maximizes the accuracy of the DAC for the transmission amplifier can be applied to the probe. Further, since the power supply voltage can be adjusted according to the maximum amplitude voltage of the transmission vibration, there is an effect that power consumption can be remarkably reduced.

  In addition, since a linear amplifier is used as the transmission amplifier circuit, it is possible to perform signal processing that slightly changes the voltage applied to the ultrasonic transducer array in order to improve the resolution of the ultrasonic beam. In other words, a transmission that can be processed with low noise by weighting the amplitude of the transmission wave sent from the ultrasonic transducer array to the diagnosis target and narrowing the entire beam, or changing the voltage amplitude of each pulse of the burst wave. There is an effect that it becomes possible to generate.

  The second feature of the present embodiment is as follows. A pre-stage transmission amplifier circuit 23 is provided in the main body 3 of the ultrasonic diagnostic apparatus, a transmission amplifier circuit 21 is provided in the relay point unit 2, and a common wiring provided in the cable 4 is used for transmission and reception signals. The input of the transmission amplifier circuit 21 is provided with a disable signal 31 for selecting whether or not to operate the switch circuit 26 and the output transistor. Further, when the transmission amplifier circuit 21 is operated, the transmission / reception separation circuit is arranged so that the signal is not transmitted to the input of the transmission amplifier circuit through the transmission / reception separation circuit connected to the operated transmission amplifier circuit. 11 is provided with a disable signal 31.

  The function of the disable signal 31 may be provided not in the transmission / reception separating circuit 11 but in the preceding receiving amplifier circuit 12. Alternatively, a switch circuit may be provided in series with the transmission / reception separating circuit 11 and the preceding receiving amplifier circuit 12 and controlled by the disable signal 31.

  As described above, in this embodiment, for a non-continuous transmission such as a burst wave, one common wiring can be used for transmission and reception of waves to one transducer 34. The number of wires can be reduced.

  In addition, when the transmission is discontinuous, it is received by the same vibrator as that used for sending the wave, passes through the same wiring as that used for transmission through the transmission / reception separation circuit 11. The signal is returned to the receiving amplifier circuit 12. When this reception signal passes through the transmission / reception separation circuit 11, the switch circuit 26 provided at the input of the transmission amplifier circuit 21 is cut off, and the disable signal 31 is used to cut off the output transistor of the transmission amplifier circuit 21. . As a result, it is possible to reliably prevent a malfunction that the transmission amplifier circuit 21 amplifies the received signal that has returned to the input terminal of the transmission amplifier circuit 21 via the transmission / reception separating circuit 11.

  That is, the transmission amplifier circuit 21 can turn off the main parts of the low-voltage circuit unit and the high-voltage circuit unit of the transmission amplifier circuit 21 by the switch circuit 26 and the disable signal 29. For this reason, there is an effect that leakage voltage can be reliably suppressed to the output terminal when the transmission amplifier circuit 21 is to be shut off.

  For example, in the case of only the switch circuit 26, when the output terminal voltage of the transmission amplifier circuit 21 fluctuates, the signal is transmitted again to the output terminal through the feedback circuit, so that the output terminal voltage fluctuates and causes noise. On the other hand, when only the output transistor is turned off, there is a problem that when the signal is transmitted to the previous circuit section in the amplifier circuit, the previous circuit operates, and further, the signal is transmitted to the output terminal via the feedback circuit. As in this embodiment, the switch circuit 26 is provided at the input terminal to cut off the input to the transmission amplifier circuit 21, and the output transistor is also cut off by the disable signal 29, so that the noise is reliably suppressed and the signal is transmitted. It becomes possible to block.

  On the other hand, for continuous transmission, the transmission / reception separation circuit 11 connected to the transmission amplifier circuit 21 that amplifies the transmission is set to a cutoff state by the disable signal 31, and the reception signal transmits the transmission. It is received by a vibrator different from the vibrator being sent. Then, a signal is transmitted to the main body 3 of the ultrasonic diagnostic apparatus through a transmission / reception separation circuit and wiring different from the transmission. At this time, the transmission amplifier circuit which does not serve as a signal path is in a state where the output transistor is cut off by the disable signal 29, and the switch circuit of the input terminal is cut off, so that the transmission amplifier circuit which does not need to be operated can be obtained. Can be shut off reliably. For this reason, in particular, when a transmission amplifier circuit having two or more channels is realized in a semiconductor integrated circuit, it is effective in preventing interference between the transmission amplifier circuits and reducing power consumption.

  The third feature of the present embodiment is that the transmission amplifier circuit 21 is formed in the relay point portion arranged near the probe 1 and the preceding transmission amplifier circuit 23 which is the second transmission amplifier circuit is subjected to ultrasonic diagnosis. It is provided in the apparatus main body 3. The output amplitude of the pre-stage transmission amplifier circuit 23 is about 10 Vpp, and the output amplitude of the transmission amplifier circuit 21 is about 120 Vpp to 10 Vpp.

  For example, the length of the cable 5 from the relay point portion to the probe housing 1 is about 15 cm to 100 cm, which is about half or less than the length from the transmission amplifier to the transducer of the conventional ultrasonic diagnostic apparatus. The cable length from the relay point unit 2 to the DAC 8 in the main body 3 of the ultrasonic diagnostic apparatus is about 50 cm to 200 cm.

  As described above, in this embodiment, the transmission signal can be voltage amplified by the two-stage amplifier circuit composed of the previous-stage transmission amplifier circuit 6 and the transmission amplifier circuit 21, so that the voltage gain of each amplifier circuit can be lowered. In general, high frequency characteristics are easily obtained when the voltage gain of the amplifier circuit is lowered. For this reason, there is an effect that high-frequency operation can be easily performed even if the voltage gain of the entire transmission amplifier is increased.

  Further, since the distance between the transmission amplifier circuit 21 and the ultrasonic transducer 34 can be shortened, the parasitic component of the cable 5 serving as the load of the transmission amplifier circuit 21 is reduced, and further, the current driving of the output transistor of the transmission amplifier circuit 21 is performed. There is no need to increase the ability. For this reason, there is an effect that the transmission amplifier can be easily increased in frequency and size.

  In addition, since the size of the probe can be reduced as compared with the case where the transmission amplifier circuit 21 is placed in the probe housing 1, there is an effect that usability is improved.

  FIG. 3 is a circuit diagram according to the second embodiment of the ultrasonic diagnostic apparatus of the present invention, and shows a specific circuit of the transmission amplifier circuit 21 and the feedback resistors 27 and 28 of FIG. MN1 to MN13, MN14x, and MN14y are n-channel MOSFETs or npn transistors. MP1 to MP13 are p-channel MOSFETs or pnp transistors.

  The basic configuration of this circuit is a current feedback type operational amplifier circuit in which the gate terminals of MN11 and MP11 are normal phase input terminals and the source terminals of MN10 and MP10 are negative phase input terminals. INV1 and INV2 are inverter circuits, and SW1 is a switch circuit. GAIN is a terminal controlled by the transmission amplifier feedback circuit control signal 23 shown in FIG. 1. R1 corresponds to the impedance 27, and R2x and R2y correspond to the impedance 28.

  The VDDH terminal is connected to the positive high-voltage power supplies 15 and 17, the VDDL terminal is connected to the positive low-voltage power supply 19, the VSSH terminal is connected to the negative high-voltage power supplies 16 and 18, the VSSL terminal is connected to the negative low-voltage power supply 20, and the GND terminal Is connected to the ground 7. The ENABLE terminal is an enable terminal and is connected to a signal that combines the functions of the enable signal 29 and the enable signal 30. The IN terminal is an input terminal 47 and the OUT terminal is an output terminal 48.

  The first feature of the present embodiment is that a GAIN terminal is provided to control the voltage gain of the transmission amplifier, and the ratio of the impedances 27 and 28 constituting the feedback circuit is switched by the GAIN terminal by the switch circuit SW1. That is, the voltage gain of the circuit 21 can be controlled.

  In the case of outputting a high voltage (for example, output voltage ± 60 V), the high-voltage power supply voltage is set to ± 75 V, and the voltage gain is set to (R1 + R2x) / R2x because MN14x and MN14y are turned on. When a low voltage is output (for example, output voltage ± 10 V), the high-voltage power supply voltage is set to ± 12 V, and the voltage gain is set to (R1 + R2x + R2y) / (R2x + R2y) because MN14x and MN14y are turned off. For example, if R1 = 3 kΩ, R2x = 50Ω, and R2y = 250Ω, the voltage gain can be controlled to about 60 and about 10, respectively.

  Therefore, for example, when a high voltage is output with the input voltage kept at a maximum of ± 1V, the power supply voltage is ± 75V and the output voltage is ± 60V, and when a low voltage is output, the power supply voltage is ± 12V. The voltage can be ± 10V. That is, in the linear amplifier circuit of the present invention, the power supply voltage ratio can be set to be twice or more and the voltage gain can be set to be twice or more.

  In this way, constant control of the feedback circuit is performed when the power supply voltage of the transmission amplifier circuit changes. As in the first embodiment, when the voltage level of the transmission signal is changed depending on the type of diagnostic mode and the type of ultrasonic transducer incorporated in the probe, the voltage gain of the transmission amplifier circuit can also be changed. A transmission signal that maximizes the accuracy of the DAC for the wave amplifier can be applied to the probe. Further, since the power supply voltage can be adjusted in accordance with the maximum amplitude voltage of the transmission vibration, there is an effect that power consumption can be significantly reduced.

  The second feature of this embodiment is that the switch circuit has two MOSFETs MN14x and MN14y connected in reverse and connected to both ends of impedance R2y, which is a component that changes the impedance value of impedance 28. Yes. Thereby, the impedance R2y is short-circuited by raising the gate voltages of the MN14x and MN14y beyond the voltage range at both ends of the impedance R2y.

  For this reason, the voltage at both ends of the impedance R2y changes positively or negatively with respect to the reference potential (ground), but the impedance value of the impedance 28 can be controlled to R2x or R2x + R2y. For this reason, there is an effect that the voltage gain of the transmission amplifier circuit 21 in which the input voltage and the output voltage change positively and negatively with respect to the reference potential (ground) can be controlled.

  The third feature of this embodiment is that MP10 and MN10 can be turned off by setting the enable terminal ENABLE to a low potential, so that the signal can be cut off from the input terminal IN (switch 26 in FIG. 1), and MP4 and MN4 can also be turned off. Therefore, the output transistors MN1 and MP1 of the transmission amplifier circuit can be turned off. Therefore, even if noise is input to the output terminal, the output elements MN1 and MP1 do not malfunction. That is, the enable terminal ENABLE plays the role of 29 and 30 in FIG.

  As a result, similar to the first embodiment, it is possible to sufficiently prevent noise generation and interference between circuits which are particularly problematic in the semiconductor integrated circuit, and to reduce the power consumption.

  FIG. 4 is a circuit diagram according to the third embodiment of the ultrasonic diagnostic apparatus of the present invention, which is another circuit example for realizing the transmission amplifier circuit 21 shown in FIG.

  The feature of this embodiment is that two sets of feedback circuits, an A circuit and a B circuit, are provided without connecting SW1 to the impedance used in the feedback circuit as in the second embodiment. When the enable signal ENABLE_a is set to the high potential and the enable signal ENABLE_b is set to the low potential, the A circuit operates, and the voltage gain is determined by the feedback circuit 45 including the impedances R1a and R2a. When the enable signal ENABLE_a is set to a low potential and the enable signal ENABLE_b is set to a high potential, the B circuit operates, and the voltage gain is determined by the feedback circuit 46 including the impedances R1b and R2b. Therefore, the voltage gain can be changed using the enable signals ENABLE_a and ENABLE_b depending on the value of the power supply voltage of the transmission amplifier circuit.

  In this embodiment, since an increase in parasitic capacitance due to the addition of a switch to the feedback circuit can be avoided, there is an effect that the frequency characteristic does not deteriorate in the feedback circuit section. In addition, although the feedback circuit section and the previous stage circuit section of the transmission amplifier circuit are provided for each of A and B, the output transistors (MN2, MN1) of the transmission amplifier circuit that require a large chip area in the case of a semiconductor integrated circuit , MP1, and MP2) are common, so that the transmission amplifier circuit can be reduced in size and cost.

  According to the present embodiment, as in the first and second embodiments, the accuracy of the DAC for the transmission amplifier is maximized even if the type of the diagnostic mode or the type of the ultrasonic transducer incorporated in the probe changes. There is an effect that it is possible to provide a high-accuracy transmission amplifier circuit that makes the best use of it.

  FIG. 5 is a block circuit diagram according to the fourth embodiment of the ultrasonic diagnostic apparatus of the present invention, so that the voltage gain of the transmission amplifier circuit can be automatically varied together with the value of the power supply voltage of the transmission amplifier circuit. This is an example in which a multiplication circuit is used in the transmission amplifier circuit.

  The transmission amplifier circuit 38 outputs a voltage proportional to the product of the voltage V1 and the voltage V2. In the transmission amplifier circuit 38 of this embodiment, an operational amplifier circuit having a feedback circuit with a fixed voltage gain can be used as a differential-single-end conversion circuit. In addition, when the symbol of a present Example and the symbol of Example 1 are the same, the same element is shown.

  The feature of this embodiment is that a transmission signal from the DAC 8 via the preceding transmission amplifier circuit 23 is input to the transmission amplifier circuit 38 as a voltage V1, and the power supply voltage monitor circuit 37 comprising impedances 35 and 36 is used to transmit the transmission amplifier circuit. A voltage proportional to the power supply voltage is applied as V2.

  As a result, the transmission signal V1 increases in voltage gain in proportion to the value of the power supply voltage, and is output as the output voltage Vout (= k · V1 · V2). Here, k is a proportionality constant. Examples of the multiplication circuit 21 include P.I. R. This can be realized by using a Gilbert-type multiplier described on pages 266 to 269 of Gray's "Analog Integrated Circuit Design Technology (Part 2)" (issued July 10, 2003, 4th edition: Baifukan). .

  According to the present embodiment, the voltage gain can be automatically changed simply by changing the voltage of the power supply voltage terminals 40 and 41 of the transmission amplifier circuit 38, so that the control circuit is simplified. For this reason, in the present embodiment, a high-accuracy transmission signal that maximizes the accuracy of the DAC for the transmission amplifier can be obtained by simply changing the voltages of the power supplies 40 and 41 without using the switches 13 and 14. Since it can be applied to the probe, compared to the case of the first embodiment, there is an effect that it is possible to perform optimum driving with respect to waveforms of various output voltage amplitudes. Moreover, since the power supply voltage can be adjusted in accordance with the maximum amplitude voltage of the transmission vibration as in the first embodiment, there is an effect that the power consumption can be significantly reduced.

  Further, the switch circuit 26 (controlled by the enable signal 30) and the enable signal 29 can reliably cut off the transmission amplifier circuit that does not need to be operated as in the first embodiment. (Embodiment 1 is configured using a multiplication circuit) It is effective for noise generation, interference between transmission amplifiers, and low power consumption.

  FIG. 6 shows an external view of the ultrasonic diagnostic apparatus of the present invention. The ultrasonic diagnostic apparatus includes a main body 3, a transmission amplifier circuit (21 in the first embodiment, 38 in the fourth embodiment), a relay point portion 2, and a probe housing 1. 4 and 5 are cables, 107 is a non-examiner, and 108 is a bed. The display unit 101 displays the diagnosis result.

  The feature of this embodiment is that the relay point portion 2 in which the transmission amplifier circuit is housed is provided near the probe housing 1, and the cable 4 connecting the relay point portion 2 and the ultrasonic diagnostic apparatus main body 3 is connected by the telescopic support portion 106. I support it. The expansion / contraction support part 106 is provided so that it can be extended and contracted as required.

  For this reason, in this embodiment, the cable 5 which is a load component of the transmission amplifier circuit can be shortened, and there is an effect that the transmission amplifier circuit can be increased in frequency and size.

  Further, the relay point portion 2 having the built-in transmission amplifier circuit is provisionally fixed by the expansion / contraction support portion 106 so as not to interfere with the inspection, and can be moved to some extent as necessary. For this reason, there is an effect that usability is improved.

  FIG. 7 is a basic circuit diagram of the linear amplifier of the transmission amplifier circuit shown in FIG. 3 according to the sixth embodiment of the present invention. The high breakdown voltage MOSFETs MN10 and MP10 shown in Fig. 3 used on the negative phase side of the linear amplifier are respectively a cascode connection of a high breakdown voltage n-channel MOSFET MN10H and a low breakdown voltage n-channel MOSFET MN10L, a high breakdown voltage p-channel MOSFET MP10H and a low breakdown voltage p Cascade connection of channel MOSFET MP10L. Here, VDDM and VSSM are power supply terminals between VDDH, VSSH and VDDL, VSSL, and are set in the circuit so that the voltage is substantially fixed or an external power supply is used.

  In this embodiment, there is an effect that it is possible to simultaneously realize a wide band by using a low breakdown voltage MOSFET having excellent high frequency characteristics and a high voltage by using a high breakdown voltage MOSFET.

  The source terminals and body terminals of the low-voltage n-channel MOSFET MN11 and the low-voltage p-channel MOSFET MP11 connected to the positive-phase terminal side of the amplifier as well as the four MOSFETs connected to the negative-phase terminal side of these linear amplifiers All are connected so that no substrate bias is applied. That is, unlike the normal MOSFET circuit, the body terminal of the n-channel MOSFET is not connected to the lowest voltage terminal, and the body terminal of the p-channel MOSFET is not connected to the highest voltage terminal.

  In this embodiment, since there is no substrate bias effect due to the reverse bias of the source terminal and the body terminal, there is no problem that the threshold voltage of the MOSFET changes depending on the value of the source terminal voltage or the mutual conductance gm decreases. There is an effect.

  FIG. 8 shows a seventh embodiment of the present invention, and is a basic circuit diagram for explaining the characteristics of the linear amplifier of the transmission amplifier circuit shown in FIG. I1 and I2 are current sources.

  In the present embodiment, the connection method between the MN 11 and the MP 11 connected to the positive phase terminal is only different from that in FIG. 7, and other configurations and effects are the same as those in the sixth embodiment.

  9 and 10 are semiconductor integrated circuit diagrams showing a linear amplifier of a transmission amplifier circuit according to the eighth embodiment of the present invention.

  FIG. 9 is a plan view and a plan view of a high breakdown voltage n-channel MOSFET (for example, MN10H), a high breakdown voltage p-channel MOSFET (for example, MP10H), a low breakdown voltage n-channel MOSFET (for example, MN10L), and a low breakdown voltage p-channel MOSFET (for example, MP10L). A sectional view of aa ′ is shown.

  FIG. 10 shows a plan view of a capacitor (for example, Ca, Cb) and a high voltage resistance (for example, R1a) and a cross-sectional view of the plan view bb ′.

  The linear amplifier has an SOI (Silicon On Insulator) structure suitable for obtaining high frequency and high withstand voltage characteristics. In the SOI structure, a silicon layer is provided on an insulating layer 56 such as silicon dioxide on a silicon substrate 55, and a semiconductor element is formed thereon. A trench groove for element isolation is formed in the semiconductor layer so as to reach the insulating layer 56, and individual elements can be separated by the insulating layer.

  In this embodiment, the trench for insulation has a structure composed of an insulating layer 58 such as silicon dioxide and polycrystalline silicon 59. 57a is an n-type semiconductor region in which elements are formed, 57c is an n-type semiconductor region (which may be a p-type semiconductor) connected to a fixed potential, and 57b is provided between the semiconductor region 57c and the semiconductor region 57a. This is a floating n-type semiconductor region (which may be a p-type semiconductor) whose potential is not fixed. Thus, by providing the floating region 57b between 57c and 57a, the parasitic capacitance of the element isolation region can be lowered. For this reason, it is possible to increase the frequency of the circuit and to further reduce the interference between elements.

  60 is an n-well semiconductor layer, 61 is a p-well semiconductor layer, 62 is an n-type semiconductor layer, 63 is a p-type semiconductor layer, 64 is an n-type channel diffusion layer, 65 is a p-type channel diffusion layer, and 66 is a p-type semiconductor layer 67 is an n-type semiconductor layer, 68 is a gate oxide film, and 69 is a polycrystalline silicon gate layer. Reference numerals 51, 52, 53, and 54 correspond to the connections shown in FIGS. Since each element is separated by an insulating layer, each MOSFET can directly connect a source and a body to constitute a transmission amplifier circuit which is a linear amplifier shown in FIGS. 3, 4, 7, and 8. FIG.

  In addition, the capacitor has a structure having a terminal on the n-type diffusion layer side and a terminal on the gate electrode side, but is connected in series in order to ensure withstand voltage, and the capacity for the positive and reverse voltages can be made symmetrical in the positive and negative directions. In this way, the terminals are connected in series so as to change the connection direction. Further, the high withstand voltage resistance is formed by a p-type region 63 formed in an island separated by a trench groove.

  Here, although the floating n-type region 57a remains on the insulating layer 56 under the p-type semiconductor layer 63, the potential of the resistance terminal fluctuates positively and negatively because it is separated into trench grooves. However, a high withstand voltage resistor can be realized without generating parasitic elements. Therefore, it is suitable for the feedback resistors R1, R2, etc.

  The linear amplifier according to the present embodiment enables the transmission amplifier circuit described in the embodiment 1-4 to be a semiconductor integrated circuit. Therefore, it is easy to reduce the size, cost, and frequency of the transmission amplifier circuit. As a result, it is possible to reduce the size and cost of the ultrasonic diagnostic apparatus.

  Needless to say, the linear amplifier described in this embodiment can be used for amplification in other high withstand voltage broadband fields.

The block circuit diagram by one Example of the ultrasonic diagnosing device of this invention. The linear characteristic figure of the transmission amplifier circuit part by this invention. The circuit diagram which shows an example of a transmission amplifier circuit part. The circuit diagram which shows the other example of a transmission amplifier circuit part. The block circuit diagram by the other Example of the ultrasonic diagnosing device of this invention. 1 is an external view of an ultrasonic diagnostic apparatus of the present invention. The circuit diagram of the linear type amplifier which shows the specific structure of a transmission amplifier circuit part. The circuit diagram of the linear type amplifier which shows the other specific structure of a transmission amplifier circuit part. The semiconductor integrated circuit sectional drawing and top view of a linear amplifier. A cross-sectional view and a plan view of a semiconductor integrated circuit of a capacitor of a linear amplifier and a high voltage resistance.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Probe housing, 2 ... Relay point part, 3 ... Ultrasonic diagnostic apparatus main body, 4, 5, 6 ... Cable, 7 ... Reference voltage (ground), 8 ... DAC, 9 ... Receive amplifier circuit, 12 ... Pre-stage reception Wave amplifier circuit, 11 ... Transmission / reception separation circuit, 13 and 14 ... High-voltage switch circuit, 15 and 16 ... High-voltage power supply for transmission circuit (for high-voltage transmission), 17, 18 ... High-voltage power supply for transmission circuit (for low-voltage transmission) , 19, 20... Low-voltage power supply for transmission circuit, 21... Transmission amplifier circuit, 22... Feedback circuit for transmission amplifier, 23... Previous-stage transmission amplifier circuit, 24 and 25. , 27, 28 ... impedance for feedback circuit, 29 ... disenable control line for transmission amplifier, 30 ... input switch enable control line, 31 ... disenable control line for transmission / reception separating circuit, 32, 35, 36 ... 33... Sending amplifier feedback circuit control signal 34... Ultrasonic transducer 37. Power supply voltage monitoring circuit 38. Multiplier circuit 40 and 41. High-voltage power supply for transmitting circuit 55. Silicon substrate 56. SiO layer, 57a ... n-type semiconductor region, 57b ... floating n-type semiconductor region, 57c ... n-type semiconductor region, 58 ... insulating layer, 59 ... polycrystalline silicon, 60 ... n-well semiconductor layer, 61 ... p-well semiconductor layer 62 ... n-type semiconductor layer, 63 ... p-type semiconductor layer, 64 ... n-type channel diffusion layer, 65 ... p-type channel diffusion layer, 66 ... p-type semiconductor layer, 67 ... n-type semiconductor layer, 68 ... gate oxide film 69 ... polycrystalline silicon gate layer.

Claims (6)

In an ultrasonic diagnostic apparatus having a transmission amplifier circuit for amplifying a transmission signal and an ultrasonic transducer to which a voltage output from the transmission amplifier circuit is applied,
In the transmission amplifier circuit, the voltage gain is controlled by a negative feedback circuit, and the power supply voltage of the transmission amplifier circuit is higher than that of the first mode in the first mode in which the power supply voltage of the transmission amplifier circuit is high and the voltage gain is high. The transmission amplifier circuit has an output voltage proportional to a voltage value obtained by multiplying the input voltage value and the power supply voltage value on the output terminal side. An ultrasonic diagnostic apparatus comprising a linear amplification characteristic . In claim 1,
In the first mode and the second mode, the voltage gain is controlled by changing the circuit constant of the negative feedback circuit. In claim 1,
The transmission amplifier circuit includes a DAC for a transmission signal,
A pre-stage transmission amplifier circuit is provided between the transmission amplifier circuit and the transmission signal DAC,
Provided in parallel with the transmission amplifier circuit is a transmission / reception separation circuit that can be controlled to pass or block the reception signal returned from the ultrasonic transducer between the input terminal and the output terminal of the transmission amplifier circuit,
The input circuit unit of the transmission amplifier circuit cuts off not only the transmission signal transmitted from the transmission signal DAC via the preceding transmission amplifier circuit, but also the reception signal returned through the transmission / reception separation circuit. A switch circuit capable of
The ultrasonic diagnostic apparatus further comprises a switch circuit capable of turning off the output transistor of the transmission amplifier circuit. In claim 3,
In the first mode and the second mode, the voltage gain is controlled by changing the circuit constant of the negative feedback circuit. In claim 3,
A first switching function for turning off an input side transistor to prevent transmission of a signal incident on the input terminal and a second switching function for turning off an output transistor of the transmission amplifier circuit are also provided. Ultrasonic diagnostic equipment. In claim 4,
A first switching function for turning off an input side transistor to prevent transmission of a signal incident on the input terminal and a second switching function for turning off an output transistor of the transmission amplifier circuit are also provided. Ultrasonic diagnostic equipment.

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