JP2013153855A - Ultrasonic probe and ultrasonic diagnostic apparatus - Google Patents

Abstract

An ultrasonic probe capable of preventing an increase in circuit scale and realizing a reduction in size and weight is provided.
An ultrasonic probe includes a transducer, a preamplifier having an input side connected to the transducer side, and an output side connected to a transmission / reception unit that transmits and receives a transmission signal and a reception signal; A transmission bypass unit 7 that is connected between a transmission / reception unit and the vibrator, passes the transmission signal and blocks the reception signal, and is connected between a power supply terminal of the preamplifier and a first power supply, And a floating unit 31 that electrically biases the bias voltage of the preamplifier when transmitting a transmission signal and electrically biases the bias potential when receiving the reception signal.
[Selection] Figure 1

Description

  The present invention relates to an ultrasonic probe and an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic probe and an ultrasonic diagnostic apparatus that bring a bias potential of a preamplifier into a floating state.

  Generally, an ultrasonic diagnostic apparatus includes a transmission circuit that generates a high-voltage AC signal inside the apparatus. A high-voltage transmission pulse (transmission signal) generated by the transmission circuit is transmitted to the ultrasonic probe via the cable, and excites an ultrasonic transducer in the ultrasonic probe. Further, the ultrasonic wave reflected and returned from the living body is received by the ultrasonic transducer. Like the transmission signal, the received signal is transmitted to the inside of the ultrasonic diagnostic apparatus via a cable, separated by the TR separation circuit (transmission / reception separation circuit), transmitted to the reception circuit, amplified, and transmitted to the image processing unit. Is done.

  The received signal is a very weak signal of about several tens to several hundred mV. Therefore, the signal level of the received signal is lowered due to the voltage division due to the parasitic capacitance of the cable, or the SNR is significantly deteriorated due to the influence of the insertion loss of the cable and the parasitic resistance of the high voltage switch. For this reason, it has been proposed that a preamplifier is provided at the grip end portion in the ultrasonic probe (probe) to amplify the received signal when transmitted to the cable, thereby relatively reducing the influence of noise. .

  For example, Patent Document 1 and Patent Document 2 are known as circuits (including a transmission / reception separation circuit and a high breakdown voltage switch) in which a preamplifier is provided in an ultrasonic probe.

Japanese Unexamined Patent Publication No. 63-177839 JP 2007-319286 A

  However, in the conventional ultrasonic diagnostic apparatus, when the preamplifier is accommodated in the grip end portion in the ultrasonic probe, the grip end portion is a place that is directly held by the operator. Usability is greatly affected. Therefore, in order to house the preamplifier in the grip end part, it is very important that the circuit is small and light. On the other hand, the circuit scale of a transmission / reception separation circuit and a high voltage switch that require a large number of high-voltage components is relatively large. In addition, a control circuit and an open / close signal for opening and closing the switch are required, and the circuit scale becomes relatively large. Further, the high withstand voltage component is inferior in performance in terms of frequency characteristics, operation speed, power consumption, and the like, as compared with the low withstand voltage component. Therefore, a circuit configuration having as few as possible these high voltage components is desired, and a simple circuit configuration that does not require control for opening and closing the switch is desired.

  The present invention has been made in view of the conventional problems, and prevents an increase in circuit scale of a circuit associated with a transmission function, a reception function, and a transmission / reception function, and includes a small and lightweight ultrasonic probe and the same. An object is to provide an ultrasonic diagnostic apparatus.

  The ultrasonic probe of the present invention includes a transducer, a preamplifier having an input side connected to the transducer side and an output side connected to a transmission / reception unit side that transmits and receives transmission signals and reception signals, the transmission / reception unit, and the vibration A transmission bypass unit that passes between the transmission signal and blocks the reception signal, and is connected between the power terminal of the preamplifier and the first power source, and at the time of transmission of the transmission signal, A floating portion that electrically floats the bias potential of the preamplifier and that electrically unfloats the bias potential upon reception of the received signal, the floating portion including a second power source, A suppression circuit that is connected in series between the first power source and the second power source and suppresses the amount of current flowing to the first power source, and the first power source and the second power source. Comprising a first diode connected in series, and a second diode connected between the connecting portion and the power supply terminal of the preamplifier between the suppression circuit and the first diode.

  According to this configuration, the floating unit that realizes the floating state includes the second power supply, the suppression circuit, and the first diode instead of the large-scale circuit, thereby preventing an increase in circuit scale, miniaturization, and Weight reduction can be realized.

  In the ultrasonic probe of the present invention, the suppression circuit is an impedance.

  According to this configuration, the floating unit that realizes the floating state includes impedance that is a small-scale circuit instead of a large-scale circuit, thereby preventing an increase in the circuit scale and realizing a reduction in size and weight. it can.

  In the ultrasonic probe of the present invention, the impedance includes a resistor and an inductor connected in series.

  According to this configuration, the floating unit that realizes the floating state includes a resistor and an inductor connected in series, which are small-scale circuits, instead of a large-scale circuit, thereby preventing an increase in circuit scale, miniaturization, and Weight reduction can be realized.

  In the ultrasonic probe of the present invention, the resistor has a high breakdown voltage with respect to the transmission signal.

  According to this configuration, the withstand voltage (high withstand voltage) of the floating portion with respect to a high-voltage transmission signal can be realized.

  In the ultrasonic probe of the present invention, the suppression circuit is a constant current circuit.

  According to this configuration, by providing the constant current circuit as the suppression circuit, the current of the suppression circuit at the time of transmission of the transmission signal can be reduced, so that power consumption can be suppressed and the recovery time can be shortened. Can do.

  In the ultrasonic probe of the present invention, the transistor of the constant current circuit has a high breakdown voltage with respect to the transmission signal.

  According to this configuration, the withstand voltage (high withstand voltage) of the floating portion with respect to a high-voltage transmission signal can be realized.

  In the ultrasonic probe of the present invention, the first diode and the second diode have a high breakdown voltage with respect to the transmission signal.

  According to this configuration, the withstand voltage (high withstand voltage) of the floating portion with respect to a high-voltage transmission signal can be realized.

  In the ultrasonic probe of the present invention, when the first power source is a positive power source, the potential of the first power source is higher than the potential of the second power source, and the first power source is negative. In the case of a power source, the potential of the first power source is lower than the potential of the second power source.

  According to this configuration, in a steady state, a current flows from the first power supply to the second power supply on the positive power supply side, and a current flows from the second power supply to the first power supply on the negative power supply side, and at the same time, a current flows to the preamplifier. However, when the large amplitude voltage of the transmission signal is applied, the floating unit can float the potential of the preamplifier itself.

  The ultrasonic probe of the present invention includes a bias circuit connected between the input / output terminal of the preamplifier and the power supply terminal.

  According to this configuration, the voltage applied between the terminals of the preamplifier can be kept at a low voltage by guiding the high-voltage transmission signal to the power supply side of the preamplifier.

  In the ultrasonic probe of the present invention, the bias circuit includes at least one of an input bias circuit connected to the input side of the preamplifier and an output bias circuit connected to the output side of the preamplifier.

  According to this configuration, the voltage applied between the terminals of the preamplifier can be kept at a low voltage by guiding the high-voltage transmission signal to the power supply side of the preamplifier.

  In the ultrasonic probe of the present invention, the preamplifier includes at least one of an emitter follower by a transistor and a source follower by an FET.

  In other words, in the probe of the present invention, the preamplifier can be constituted by an emitter follower by a transistor or a source follower by an FET. By using a high-breakdown-voltage transistor with this configuration, the second diode in the floating portion is not necessary, and a circuit configuration with a small circuit scale can be realized.

  The ultrasonic probe of the present invention includes a plurality of the transducers, and the preamplifier and the bias circuit are connected to each transducer, and the first power source, the second power source, the suppression circuit, The first diode is shared by the plurality of vibrators.

  According to this configuration, even when there are a plurality of vibrators, the common use of the first power source, the second power source, the suppression circuit, and the first diode prevents an increase in circuit scale, reduces the size, Weight reduction can be realized.

  The ultrasonic diagnostic apparatus of the present invention includes an ultrasonic probe including a transducer, a transmission / reception unit that transmits a transmission signal to the ultrasonic probe and receives a reception signal from the ultrasonic probe, A preamplifier whose input side is connected to the transducer side and whose output side is connected to the transmission / reception unit side is connected between the transmission / reception unit and the transducer, and passes the transmission signal to block the reception signal. The transmission bypass unit is connected between the power supply terminal of the preamplifier and the first power supply, and at the time of transmission of the transmission signal, the bias potential of the preamplifier is electrically floated, and when the reception signal is received, A floating portion that electrically brings a bias potential into a non-floating state, and the floating portion is connected in series between a second power source, the first power source, and the preamplifier, A suppression circuit that suppresses the amount of current flowing to one power source, a first diode connected in series between the first power source and the second power source, the suppression circuit, and the first diode; And a second diode connected between a power supply terminal of the preamplifier.

  According to this configuration, the floating unit that realizes the floating state includes the second power supply, the suppression circuit, and the first diode instead of the large-scale circuit, thereby preventing an increase in circuit scale, miniaturization, and Weight reduction can be realized.

  According to the present invention, the floating unit that realizes the floating state includes the second power source, the suppression circuit, and the first diode instead of the large-scale circuit, thereby preventing an increase in the circuit scale and reducing the size and weight. Therefore, it is possible to provide an ultrasonic probe and an ultrasonic diagnostic apparatus that have the effect of realizing the above.

It is the figure which showed an example of the ultrasonic diagnosing device of the 1st Embodiment of this invention. It is the figure which showed an example of the suppression circuit which is an impedance. It is a figure explaining operation | movement of the ultrasonic diagnosing device at the time of reception of a received signal. It is a figure explaining operation | movement of the ultrasound diagnosing device at the time of transmission of a transmission signal. It is the figure which showed an example of the input bias circuit. It is the figure which showed an example of the output bias circuit. It is the figure which showed an example of the ultrasonic diagnosing device of the 2nd Embodiment of this invention. It is the figure which showed an example of the suppression circuit which is a constant current circuit. It is a figure which shows an example of the constant current circuit using a field effect transistor (FET).

(First embodiment)
Hereinafter, an ultrasonic diagnostic apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an ultrasonic diagnostic apparatus 100 according to a first embodiment of the present invention.

  As shown in FIG. 1, the ultrasound diagnostic apparatus 100 includes an ultrasound probe 1, a transmission / reception unit 2, a preamplifier (reception preamplifier) 4, a transmission bypass unit 7, and a floating unit 31. The ultrasonic probe 1 includes a vibrator 3. The transmission / reception unit 2 includes a transmission amplifier and a reception circuit (not shown), transmits a transmission signal to the ultrasonic probe 1, and receives a reception signal from the ultrasonic probe 1. The cable 8 connects the ultrasonic probe 1 and the transmission / reception unit 2. The preamplifier 4 has an input side (input terminal 41) connected to the vibrator 3 side and an output side (output terminal 42) connected to the transmission / reception unit 2 side. The transmission bypass unit 7 is connected between the transmission / reception unit 2 and the vibrator 3 and allows the transmission signal to pass therethrough and blocks the reception signal.

  The floating unit 31 is connected between the power supply terminal 40 of the preamplifier 4 and the first power supplies Vdd1 and Vss1, and when the transmission signal is transmitted, the bias potential of the preamplifier 4 is electrically floated and the reception signal is received. The bias potential is made electrically non-floating. The floating unit 31 is connected in series between the second power sources Vdd2 and Vss2 and the first power sources Vdd1 and Vss1 and the second power sources Vdd2 and Vss2, and the amount of current flowing to the first power sources Vdd1 and Vss1 is reduced. A suppression circuit 12 for suppression, a first diode 18 connected in series between the first power supply Vdd1, Vss1 and the second power supply Vdd2, Vss2, and the suppression circuit 12 and the first diode 18 And a second diode 15 connected between the connecting portion 45 and the preamplifier 4, and bias circuits 29 and 30 connected between the input / output terminals 41 and 42 of the preamplifier 4 and the power supply terminal 40. The input bias circuit 29 is connected to the input terminal 41 side (input side) of the preamplifier 4. The output bias circuit 30 is connected to the output terminal 42 side (output side) of the preamplifier 4.

  The suppression circuit 12 is an impedance. As shown in FIG. 2, the impedance (suppression circuit) 12 includes a resistor 17 and an inductor 16 connected in series. The resistor 17 has a high withstand voltage with respect to the transmission signal. The first diode 18 and the second diode 15 have a high withstand voltage with respect to the transmission signal.

  Current is supplied from the first power supplies Vdd1 and Vss1 to the power supply terminal 40 of the preamplifier 4 through the impedance 12 and the second diode 15 for preventing backflow. When the first power supply is a positive power supply, the potential of the first power supply Vdd1 is set to be higher than the potential of the second power supply Vdd2. When the first power supply is a negative power supply, the potential of the first power supply Vss1 is set to be lower than the potential of the second power supply Vss2. For example, the first power supply Vdd1 is set to + 3V, the first power supply Vss1 is set to -3V, the second power supply Vdd2 is set to + 1.5V, and the second power supply Vss2 is set to -1.5V. As a result, a current flows from the first power supply Vdd1 to the second power supply Vdd2 via the impedance 12 and the first diode 18. In addition, a current flows from the second power supply Vss2 to the first power supply Vss1 through the impedance 12 and the first diode 18.

  When the forward voltage drop of the first diode 18 is 0.6V, the second power supplies Vdd2 and Vss2 are ± 1.5V (+ 1.5V on the positive power supply side and -1.5V on the negative power supply side). The voltage of the connecting portion 45 between 12 and the first diode 18 is ± 2.1V (+ 2.1V on the positive power supply side and -2.1V on the negative power supply side).

  Assuming that the forward drop voltage of the second diode 15 is 0.6V, the voltage at the connection 45 between the impedance 12 and the first diode 18 is ± 2.1V (+ 2.1V on the positive power supply side and -2.V on the negative power supply side). 1V), the voltage of the power supply terminal 40 of the preamplifier 4 is ± 1.5V (+ 1.5V on the positive power supply side and -1.5V on the negative power supply side).

  The power supply impedance of the floating power supply in the floating unit 31 is set by the current flowing through the first diode 18. The current flowing to the first diode 18 is determined by the magnitude of the resistor 17 of the impedance 12.

  Assume that the steady-state current of the preamplifier 4 is 1 mA and the value of the resistor 17 is 450Ω. In this case, the potential difference of the impedance 12 is 0.9 V according to the equation (1). In the equations (1) to (3), the polarity (±) of the power source (positive power source and negative power source) is omitted.

  0.9V (potential difference of impedance 12) = 3.0V (voltage of first power supply Vdd1, Vss1) −2.1V (voltage of connection portion 45) (1)

  The current flowing through the first power supply is 2 mA according to the equation (2).

  2mA = 0.9V (potential difference of impedance 12) / 450Ω (resistance 17 of impedance 12) (2)

  Therefore, the current flowing through the first diode 18 is 1 mA according to the equation (3).

  1 mA = 2 mA (current flowing through the first power supply Vdd1, Vss1) -1 mA (steady current of the preamplifier 4) (3)

  As a result, the power supply impedance between the power supply terminal 40 of the preamplifier 4 and the ground can be reduced by increasing the steady current of the first diode 18. However, since the power consumption increases when the steady current of the first diode 18 is increased, the power supply impedance of the floating power supply in the floating unit 31 is adjusted by the value of the resistor 17.

  If a diode having a relatively long reverse recovery time is used as the first diode 18, the impedance between the power supply terminal 40 of the preamplifier 4 and the ground can be reduced.

  Next, the operation of the ultrasonic diagnostic apparatus 100 of the present embodiment will be described. FIG. 3 is a diagram for explaining the operation of the ultrasonic diagnostic apparatus 100 when receiving a reception signal. As shown in FIG. 3, a reception signal (˜about several hundred mVpp) smaller than the voltage ± 1.5 V applied to the power supply terminal 40 of the preamplifier 4 is received by the vibrator 3. The received signal is input to the input terminal 41 of the preamplifier 4, amplified by the preamplifier 4, and output from the output terminal 42. The reception signal amplified by the preamplifier 4 is input to the transmission / reception unit 2 via the cable 8. The solid line waveform indicates a positive reception signal, and the solid arrow indicates the flow of the positive reception signal. The dotted waveform indicates the negative reception signal, and the dotted arrow indicates the flow of the negative reception signal.

  Here, the impedance of the transmission bypass unit (back-to-back connection diode) 7 composed of the anti-parallel connection diode becomes a high impedance with respect to a signal equal to or lower than the forward voltage drop of the diode, and cuts off the reception signal. .

  FIG. 4 is a diagram for explaining the operation of the ultrasonic diagnostic apparatus 100 when transmitting a transmission signal. As shown in FIG. 4, a transmission signal (several V to several hundred Vpp) generated by the transmission / reception unit 2 is input to the vibrator 3 via the cable 8 and the transmission bypass unit 7 and irradiated with ultrasonic waves. . The solid line waveform indicates a positive reception signal, and the solid arrow indicates the flow of the positive reception signal. The dotted waveform indicates the negative reception signal, and the dotted arrow indicates the flow of the negative reception signal.

  When the positive transmission signal is input to the input / output terminals 41 and 42 of the preamplifier 4, the voltage of the power supply terminal 40 of the preamplifier 4 is substantially equal to the transmission signal by at least one of the input bias circuit 29 and the output bias circuit 30. The voltage is equivalent (or slightly smaller). When the transmission signal is positive, the second diode 15-p on the positive power supply Vdd side changes from passing to cutoff, so the first diode 18-p on the positive power supply Vdd side and the suppression circuit (impedance) 12-p. No current flows. On the other hand, when the transmission signal is positive, the second diode 15-n on the negative power supply Vss side remains in the passing state, and the first diode 18-n on the negative power supply Vss side changes from passing to blocking. A current flows to the first power supply Vss1 through the suppression circuit (impedance) 12-n, but no current flows to the second power supply Vss2. Here, the inductor 16 of the suppression circuit (impedance) 12-n has an impedance ωL corresponding to the frequency ω of the transmission signal (AC signal), and has a larger value than the DC signal (DC signal). The amount of current flowing to Vss1 is suppressed.

  When a negative transmission signal is input to the input / output terminals 41 and 42 of the preamplifier 4, at least one of the input bias circuit 29 and the output bias circuit 30 causes the voltage at the power supply terminal 40 of the preamplifier 4 to be substantially equal to the transmission signal. The voltage is equivalent (or slightly smaller). When the transmission signal is negative, the second diode 15-n on the negative power supply Vss side changes from passing to cutoff, so the first diode 18-n on the negative power supply Vss side and the suppression circuit (impedance) 12-n. No current flows through On the other hand, when the transmission signal is a negative electrode, the second diode 15-p on the positive power supply Vdd side remains in the passing state, and the first diode 18-p of the positive power supply Vdd changes from passing to shut-off. A current flows to the first power supply Vdd1 through the circuit (impedance) 12-p, but no current flows to the second power supply Vdd2. Here, since the inductor 16 of the suppression circuit (impedance) 12-p has an impedance ωL corresponding to the frequency ω of the transmission signal and has a larger value than the DC signal, the amount of current flowing to the first power supply Vdd1 is suppressed. The

  As described above, the second diode 15 (15-p, 15-n) and the first diode 18 (18-p, 18-n) operate according to the positive and negative electrodes of the sinusoidal transmission signal. Therefore, as shown in the waveform diagrams 400 and 401 of FIG. 4, the voltage waveform of the connection unit 45 (between the first diode 18 and the second diode 15) is a voltage obtained by half-waveting the transmission signal. Since a high-voltage transmission signal flows, the second diode 15, the first diode 18, and the resistor 17 of the suppression circuit (impedance) 12 are required to have a withstand voltage (high withstand voltage) higher than the peak value of the transmission signal. Is done. On the other hand, since there is the transmission bypass unit 7 composed of diodes connected in antiparallel, the voltage between the input / output terminals 41 and 42 of the preamplifier 4 is kept at a low voltage.

  In this way, the voltage between the input / output terminals 41 and 42 of the preamplifier 4 and the power supply terminal 40 is kept at a low voltage with respect to the large amplitude voltage (high voltage) of the transmission signal. The bias potential fluctuates with the transmission pulse (transmission signal) and enters a floating state. As a result, circuit withstand voltage protection of the preamplifier 4 can be realized. In other words, when the transmission pulse is positive (positive voltage), the second diode 15-p on the positive power supply Vdd side is reverse-biased and cut off, and when the transmission pulse is negative (negative voltage), the negative power supply Vss. The second diode 15-n on the side is reverse-biased and cut off, and the preamplifier 4 enters the floating state.

  When the reception signal is received, the bias potential of the preamplifier 4 returns to the original state (non-floating state), and the reception signal that is a weak AC signal blocked by the transmission bypass unit 7 is guided to the preamplifier 4. Are amplified with a predetermined gain.

  That is, the floating unit 31 electrically separates the preamplifier 4 accommodated in the ultrasound probe 1 from the power source terminal 40 of the preamplifier 4 from the first power sources Vdd and Vss, so that the preamplifier itself is transmitted during transmission of the transmission signal. The preamplifier 4 is protected from a high-voltage transmission pulse. Further, the bias potential of the preamplifier 4 is restored when the reception signal is received, and the preamplifier 4 is used as a normal reception preamplifier.

  Next, the input bias circuit 29 and the output bias circuit 30 will be described with reference to FIGS. The input bias circuit 29 and the output bias circuit 30 transfer a large amplitude voltage (high voltage) applied to the input / output terminals 41 and 42 of the preamplifier 4 to the power supply side (positive power supply Vdd side and negative power supply Vss side) of the preamplifier 4. By guiding, the voltage applied between the terminals of the preamplifier 4 is kept at a low voltage.

  As shown in FIG. 5, in the input bias circuit 29, the protection diode 21 is connected between the input terminal 41 of the preamplifier 4 and each power supply terminal 40. Two capacitors 19 connected in series and two resistors 20 connected in series are connected between a power supply terminal 40-p on the positive power supply Vdd side and a power supply terminal 40-n on the negative power supply Vss side. A midpoint 46 between the two capacitors 19 and the two resistors 20 is connected to the midpoint.

  The resistor 22 is connected between the midpoint 46 and the input terminal 41 of the preamplifier 4. As a result, the midpoint voltage between the power supply terminals 40 of the preamplifier 4 becomes the voltage of the input terminal 41.

  When the transmission signal is input to the input terminal 41 of the preamplifier 4, when the voltage of the input terminal 41 becomes near the forward drop voltage of the protection diode 21, the protection diode 21 changes from blocking to passing, and the input of the preamplifier 4. It operates so as to keep the potential difference between the terminal 41 and the power supply terminal 40 at the forward drop voltage. In addition, the capacitor 19 smoothes the change that has occurred at both power supply terminals 40. The resistor 20 discharges the charge at the time of smoothing. The resistor 22 causes the input terminal 41 to have a midpoint potential.

  In this case, the voltage between the output terminal 42 and the power supply terminal 40 remains in the potential difference of the two-stage forward drop voltage between the diode of the transmission bypass unit 7 and the protection diode 21.

  As shown in FIG. 6, in the output bias circuit 30, the protection diode 21 (Zener diode) is connected between the output terminal 42 of the preamplifier 4 and the power supply terminal 40, and the capacitor 19 is connected between the power supply terminals 40. When the voltage of both power supply terminals 40 is ± 1.5V, the Zener voltage (forward voltage drop) of the Zener diode (protective diode 21) is larger than 1.5V (for example, 1.8V). Need to be set. That is, the Zener voltage of the Zener diode (protection diode 21) needs to be set larger than the voltage of the power supply terminal 40.

  When a transmission signal is input to the output terminal 42 side of the preamplifier 4, if the voltage at the output terminal 42 is close to the forward drop voltage of the protection diode 21, the protection diode 21 made of a Zener diode changes from blocking to passing. The preamplifier 4 operates so as to keep the potential difference between the output terminal 42 and the power supply terminal 40 at the forward drop voltage. When the voltage at the output terminal 42 becomes equal to or less than the Zener voltage (forward voltage drop), the output terminal 42 changes from passing to blocking. The space between the two power supply terminals 40 is smoothed by the capacitor 19.

  In this case, the voltage between the input terminal 41 and the power supply terminal 40 remains in the potential difference of the two-stage forward drop voltage between the diode of the transmission bypass unit 7 and the protection diode 21.

  In addition, since the voltage between the input / output terminals 41 and 42 of the preamplifier 4 is maintained at a low voltage by the transmission bypass unit 7 configured by a diode connected in reverse parallel, a large amplitude voltage (high voltage) of the transmission signal is maintained. On the other hand, the input / output terminals 41 and 42 of the preamplifier 4 and the power supply terminal 40 are kept at a low voltage, and the bias potential of the preamplifier 4 fluctuates with the transmission pulse (transmission signal) so that In order to achieve this, the floating state is realized if at least one of the input bias circuit 29 and the output bias circuit 30 is provided.

  As described above, the floating unit 31 that realizes the floating state includes the impedance 12 (inductor 16 and resistor 17) and the first diode 18 that are small-scale circuits instead of the large-scale circuit such as a capacitor, thereby providing a circuit. An increase in scale can be prevented, and a small and lightweight ultrasonic probe and an ultrasonic diagnostic apparatus including the same can be provided.

(Second Embodiment)
Hereinafter, an ultrasonic diagnostic apparatus according to the second embodiment will be described with reference to the drawings. Unless otherwise specified, other configurations are the same as those of the ultrasonic diagnostic apparatus according to the first embodiment. An ultrasonic diagnostic apparatus 101 according to the second embodiment of the present invention is shown in FIG. FIG. 7 is a diagram illustrating an ultrasonic diagnostic apparatus 101 including a plurality of preamplifiers 4 and output bias circuits 30 respectively corresponding to a plurality of transducers.

  As shown in FIG. 7, the ultrasonic probe 1 includes a plurality of transducers 3. A preamplifier 4 and a bias circuit (output bias circuit 30) are connected to each vibrator 3. The first power supplies Vdd1 and Vss1, the second power supplies Vdd2 and Vss2, the suppression circuit 12 (impedance), and the first diode 18 are shared by the plurality of vibrators 3.

  As described above, the first power supplies Vdd1 and Vss1, the suppression circuit 12, the first diode 18, and the second power supplies Vdd2 and Vss2 are shared. Preamplifier 4 (4-1, 4-2, 4-3...) And output bias between the second diodes 15-x (15-1, 15-2, 15-3...) The circuit 30 (30-1, 30-2, 30-3) is configured corresponding to each vibrator 3.

  In this case, mutual crosstalk can be reduced by increasing the capacitance of the capacitor 19. Further, by increasing the amount of current normally flowing through the second power sources Vdd2, Vss2 and the first diode 18, mutual crosstalk can be reduced. Further, by selecting a diode having a long reverse recovery time as the first diode 18, mutual crosstalk can be reduced. Further, the capacitance of the capacitor 19 is increased, the amount of current normally flowing through the second power sources Vdd2, Vss2, and the first diode 18 is increased, and a diode having a long reverse recovery time is selected as the first diode 18. Thus, it is possible to shorten the time (recovery time) until the normal bias state (non-floating state) is returned from the floating state after the transmission signal is transmitted.

  Further, assuming that the phase difference between the transmission signals for driving the respective vibrators 3 is 180 °, the withstand voltage of the second diode 15 may be at least twice the transmission voltage of the transmission signal.

  As described above, even when there are a plurality of vibrators 3, by sharing the first power supplies Vdd1, Vss1, the second power supplies Vdd2, Vss2, the suppression circuit 12 (impedance), and the first diode 18, An increase in circuit scale can be prevented, and a small and lightweight ultrasonic probe and an ultrasonic diagnostic apparatus including the same can be provided.

  As mentioned above, although embodiment concerning this invention was described, this invention is not limited to these, It can change and deform | transform within the range described in the claim.

  For example, the suppression circuit 12 may be a constant current circuit. FIG. 8 is a diagram illustrating a case where the suppression circuit 12 is a constant current circuit 28 (28-1, 28-2) instead of the impedance. FIG. 9 is a diagram showing a constant current circuit 28 using a field effect transistor (FET). As shown in FIG. 9, resistors 23 are respectively connected between the first power supplies Vdd1 and Vss1 and the gates of the FETs (N-channel FET 26 and P-channel FET 27). That is, the resistor 23 is connected between the first power supply Vdd1 and the gate of the N-channel FET 26, and the resistor 23 is connected between the first power supply Vss1 and the gate of the P-channel FET 27. A resistor 24 is connected between the gates of the FETs 26 and 27 to set the gate voltage of the FETs 26 and 27. A constant current amount is set by a resistor 25 between the first power supplies Vdd 1 and Vss 1 and the sources of the FETs 26 and 27.

  Thus, by providing the constant current circuit 28 instead of the impedance as the suppression circuit 12, the current of the suppression circuit 12 at the time of transmission of a transmission signal can be reduced, so that power consumption can be suppressed. Further, the recovery time can be shortened.

  The FETs 26 and 27 (transistors) of the constant current circuit 28 have a high withstand voltage with respect to the transmission signal. That is, each of the FETs 26 and 27 is required to have a high breakdown voltage equal to or higher than the peak value of the transmission signal, like the resistor 17.

  The preamplifier 4 may include at least one of an emitter follower by a transistor and a source follower by an FET. That is, the preamplifier 4 can be configured by an emitter follower by a low breakdown voltage transistor or a source follower by a low breakdown voltage FET. Further, when the preamplifier 4 is configured by an emitter follower circuit using a high breakdown voltage transistor or a source follower circuit using a high breakdown voltage FET, the second diode 15 having a high breakdown voltage in the floating portion 31 is not necessary, and the circuit configuration is small. Can be realized.

  As mentioned above, although embodiment concerning this invention was described, this invention is not limited to these, It can change and deform | transform within the range described in the claim. According to the present embodiment, by using the floating portion 31, a low breakdown voltage process and low breakdown voltage components can be used. Therefore, a circuit configuration with a small circuit scale, high speed, and low power consumption is realized. be able to. In addition, since no switch element or the like is used, a simple circuit configuration that does not require control such as opening and closing can be realized.

  The ultrasonic probe according to the present invention has the effect of realizing a circuit configuration with a small circuit scale, high speed, and low power consumption, and an ultrasonic probe for bringing the bias potential of the preamplifier into a floating state. It is useful as a tentacle.

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Transmission / reception part 3 Transducer 4 Preamplifier 7 Transmission bypass part 8 Cable 16 Inductor 17 Resistance 21 Protection diode 28 Constant current circuit 29 Input bias circuit 30 Output bias circuit 31 Floating part

Claims (13)

A vibrator,
A preamplifier having an input side connected to the transducer side and an output side connected to a transmission / reception unit side that transmits and receives transmission signals and reception signals;
A transmission bypass unit that is connected between the transmission / reception unit and the vibrator and that blocks the reception signal by allowing the transmission signal to pass;
The preamplifier is connected between a power supply terminal of the preamplifier and a first power supply, and when the transmission signal is transmitted, the bias potential of the preamplifier is electrically floating, and when the reception signal is received, the bias potential is electrically With a floating part to be in a non-floating state,
The floating part is
A second power source;
A suppression circuit connected in series between the first power source and the second power source to suppress the amount of current flowing to the first power source;
A first diode connected in series between the first power source and the second power source;
An ultrasonic probe comprising: a connection portion between the suppression circuit and the first diode; and a second diode connected between a power supply terminal of the preamplifier.   The ultrasonic probe according to claim 1, wherein the suppression circuit is an impedance.   The ultrasonic probe according to claim 2, wherein the impedance includes a resistor and an inductor connected in series.   The ultrasonic probe according to claim 3, wherein the resistor has a high withstand voltage with respect to the transmission signal.   The ultrasonic probe according to claim 1, wherein the suppression circuit is a constant current circuit.   The ultrasonic probe according to claim 5, wherein the transistor of the constant current circuit has a high withstand voltage with respect to the transmission signal.   The ultrasonic probe according to claim 1, wherein the second diode and the first diode have a high withstand voltage with respect to the transmission signal. When the first power source is a positive power source, the potential of the first power source is higher than the potential of the second power source,
The ultrasonic wave according to claim 1, wherein when the first power source is a negative power source, the potential of the first power source is lower than the potential of the second power source. Transducer.   The ultrasonic probe according to claim 1, further comprising a bias circuit connected between an input / output terminal of the preamplifier and the power supply terminal.   9. The bias circuit according to claim 8, wherein the bias circuit includes at least one of an input bias circuit connected to the input side of the preamplifier and an output bias circuit connected to the output side of the preamplifier. Ultrasonic probe.   The ultrasonic probe according to claim 1, wherein the preamplifier includes at least one of a transistor-based emitter follower and a FET-based source follower. Including a plurality of the vibrators,
For each transducer, the preamplifier and the bias circuit are connected,
The first power supply, the second power supply, the suppression circuit, and the first diode are shared by the plurality of vibrators. The described ultrasonic probe. An ultrasonic probe including a transducer;
A transmission / reception unit for transmitting a transmission signal to the ultrasonic probe and receiving a reception signal from the ultrasonic probe;
A preamplifier whose input side is connected to the transducer side and whose output side is connected to the transmitting / receiving unit side;
A transmission bypass unit that is connected between the transmission / reception unit and the vibrator and that blocks the reception signal by allowing the transmission signal to pass;
The preamplifier is connected between a power supply terminal of the preamplifier and a first power supply, and when the transmission signal is transmitted, the bias potential of the preamplifier is electrically floating, and when the reception signal is received, the bias potential is electrically With a floating part to be in a non-floating state,
The floating part is
A second power source;
A suppression circuit that is connected in series between the first power supply and the preamplifier and suppresses the amount of current flowing to the first power supply;
A first diode connected in series between the first power source and the second power source;
An ultrasonic diagnostic apparatus comprising: a connection portion between the suppression circuit and the first diode; and a second diode connected between a power supply terminal of the preamplifier.

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