JP2008289780A - Ultrasonic diagnostic device and ultrasonic probe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lessen the difference between the rise time and the fall time of ultrasonic signals. <P>SOLUTION: Constant current setting devices 9, 10 generate voltage VCP and VCN respectively. A resistant element 6 induces charging current. A resistant element 7 induces discharging current. A transistor 3 supplies the charging current to an ultrasonic transducer 5 while applying the current to the gate of VCP. A transistor 4 outputs the discharging current from the ultrasonic transducer 5 while applying the current to the gate of VCN. Drivers 1, 2 switch ON/OFF the applied current of VCP and VCN to the gates of transistors 3, 4. Transistors 13, 14 receive VCP and VCN to their gates respectively and apply the current generated in resistant elements 11, 12 between source-drain. The constant current setting devices 9, 10 set the voltage value of VCP and VCN respectively in order to set the current values, which are generated in the resistance elements 11, 12 respectively, as the first and second setting values. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus that diagnoses a subject using ultrasonic waves transmitted from an ultrasonic transducer, and an ultrasonic probe that can be used in the ultrasonic diagnostic apparatus.

  In recent years, as a means for transmitting ultrasonic waves from a transducer in an ultrasonic probe, a circuit configuration has been provided with a positive direction switch for current discharge and a negative direction switch for suction, and generates a rectangular pulse by alternately switching them. In general, an ultrasonic diagnostic apparatus including the above is used.

  FIG. 5 is a diagram showing a part of a circuit configuration in the ultrasonic probe in such an ultrasonic diagnostic apparatus. FIG. 5 shows only the transmission unit related to the above characteristic configuration.

  In the following description, the expression “ON” and “OFF” is used as a state of the FET (field-effect transistor) for convenience. However, the ON state indicates a state where the impedance between the source and the drain is low, and is opposite to the OFF state. It shows a state where the impedance is high. In the logic waveform, a high signal level is indicated as H, and a low state is indicated as L.

In FIG. 5, signals S1 and S2 each having a signal based on a reference signal from a reference signal generator (not shown) are applied to the drivers 1 and 2, respectively. The driver 1 has a switch configuration for selecting voltages 1VHPH and 1VHPL, and outputs a voltage 1VHPH when the signal S1 is L, and outputs a voltage 1VHPL when the signal S1 is H. The output voltage of the driver 1 is applied to the gate terminal of the transistor 3 using P-CH MOSFET. As the voltage 1VHPL, a voltage value necessary for turning on the transistor 3 is given. Therefore, when the signal S1 is H, the transistor 3 is turned on. The driver 2 outputs a voltage 1VHNL when the signal S2 is L, and outputs a voltage 1VHNL when the signal S2 is H. The output voltage of the driver 2 is applied to the gate terminal of the transistor 4 using N-CH MOSFET. The transistor 4 is turned on when the signal S2 is L and turned off when the signal S2 is H. The signals S1 and S2 have different voltage values in the L state, but the time phases of the waveforms H and L are the same. Thus, the ultrasonic vibrator 5 is charged and discharged with the voltage 1VHPH and the voltage 1VHNH. As a result, the waveform of the voltage supplied to the ultrasonic transducer 5 has a pulse shape synchronized with the signals S1 and S2, and the pulse width is usually set to ½ period of the ultrasonic frequency to be transmitted. The rise time of the voltage supplied to the ultrasonic transducer 5 is determined by the drain current due to the gate-source voltage of the transistor 3 and the impedance of the ultrasonic transducer 5, and the fall time depends on the gate-source voltage of the transistor 4. It is determined by the drain current and the impedance of the ultrasonic transducer 5.
JP 2004-89694 A

  In recent years, in constructing a harmonic image that has been regarded as important in image diagnosis, it is desirable to reduce the difference between the rise time and the fall time of an ultrasonic signal as much as possible. Note that a harmonic image is an image with good contrast resolution obtained by constructing an image by detecting waveform distortion generated in a living body. Therefore, when the signal itself is distorted, it is very difficult to discriminate it from in-vivo strain, so it is important to transmit ultrasonic waves with a signal without distortion.

  However, according to the transmission unit having the conventional configuration as described above, it is difficult to align the characteristics of the transistor 3 and the transistor 4 because the physical properties of the semiconductor material itself are different. It was difficult to reduce the difference.

  The present invention has been made in view of such circumstances, and an object thereof is to reduce the difference between the rise time and the fall time in an ultrasonic signal.

  An ultrasonic diagnostic apparatus according to a first aspect of the present invention performs diagnosis of a subject using ultrasonic waves transmitted from an ultrasonic transducer, and generates a first driving voltage. Generating means; second generating means for generating a second drive voltage; first resistance element for generating a charging current for charging the ultrasonic vibrator; and discharging the ultrasonic vibrator A second resistance element for generating a discharge current for generating a first current and a P-type channel for supplying the charging current to the ultrasonic transducer when the first drive voltage is applied to a gate. Field-effect transistors, an N-channel second field-effect transistor that outputs the discharge current from the ultrasonic transducer when the second drive voltage is applied to the gate, and the first electric field. Before the gate of the effect transistor A first driver that turns on / off application of the first drive voltage; a second driver that turns on / off application of the second drive voltage to the gate of the second field effect transistor; And the first field effect transistor, the first driving voltage is applied to the gate, and a current generated in the third resistance element flows between the source and the drain. The field effect transistor, the fourth resistance element, and the second field effect transistor have the same characteristics and the second drive voltage is applied to the gate, and the current generated in the fourth resistance element is reduced. A fourth field-effect transistor that flows between the source and the drain, and the first generation unit is configured to cause the current value of the current generated in the third resistance element to be a first set value. The second generation means sets the voltage value of the second drive voltage so that the current value of the current generated in the fourth resistance element becomes the second set value. Set.

  The ultrasonic diagnostic apparatus according to the second aspect of the present invention diagnoses a subject using ultrasonic waves respectively transmitted from a plurality of ultrasonic transducers, and generates a first drive voltage. A first generating means; a second generating means for generating a second drive voltage; and a plurality of first resistors for respectively generating charging currents for charging the plurality of ultrasonic transducers. An element, a plurality of second resistance elements for generating discharge currents for discharging the plurality of ultrasonic transducers, respectively, and a plurality of elements when the first drive voltage is applied to the gate A plurality of P-channel first field effect transistors for supplying the charging current to the plurality of ultrasonic transducers, and a plurality of the discharge currents when the second drive voltage is applied to the gate. The multiple ultra A plurality of N-channel second field effect transistors output from the wave vibrators, and a plurality of ON / OFF switches for applying the first drive voltage to the gates of the plurality of first field effect transistors, respectively. A plurality of second drivers that respectively turn on / off application of the second drive voltage to the gates of the plurality of second field effect transistors, a third resistance element, A third field effect transistor having the same characteristics as the first field effect transistor, the first drive voltage being applied to the gate, and a current generated in the third resistance element flowing between a source and a drain; The fourth resistance element has the same characteristics as the second field effect transistor and the second driving voltage is applied to the gate, and the fourth resistance element And a fourth field effect transistor for causing a current generated in the child to flow between the source and the drain, and the first generation means is configured such that the current value of the current generated in the third resistance element becomes the first set value. The second drive voltage is set to the second drive voltage so that the current value of the current generated in the fourth resistance element becomes the second set value. Set the voltage value of.

  An ultrasonic probe according to a third aspect of the present invention includes an ultrasonic transducer, first generation means for generating a first drive voltage, second generation means for generating a second drive voltage, A first resistance element for generating a charging current for charging the ultrasonic transducer; a second resistance element for generating a discharge current for discharging the ultrasonic transducer; and the first A P-channel first field-effect transistor that supplies the charging current to the ultrasonic transducer when the drive voltage is applied to the gate, and the second drive voltage is applied to the gate A second N-channel field effect transistor for outputting the discharge current from the ultrasonic transducer, and a first for turning on / off the application of the first drive voltage to the gate of the first field effect transistor. 1 driver, The second driver that turns ON / OFF the application of the second drive voltage to the gate of the second field effect transistor, the third resistance element, and the first field effect transistor have the same characteristics. The first driving voltage is applied to the gate, and a third field effect transistor that causes a current generated in the third resistance element to flow between a source and a drain, a fourth resistance element, and the second electric field A fourth field effect transistor having the same characteristics as the effect transistor, the second drive voltage being applied to the gate, and a current generated in the fourth resistance element flowing between the source and the drain. 1 generating means sets the voltage value of the first drive voltage so that the current value of the current generated in the third resistance element becomes the first set value, and the second generating means First Current value of the occurring resistance element current sets the voltage value of the to be a second set value the second driving voltage.

  An ultrasonic probe according to a fourth aspect of the present invention includes a plurality of ultrasonic transducers, first generation means for generating a first drive voltage, and second generation means for generating a second drive voltage. A plurality of first resistance elements for generating charging currents for charging the plurality of ultrasonic vibrators, respectively, and a discharge current for discharging the plurality of ultrasonic vibrators, respectively. A plurality of second resistance elements for generating and a plurality of P-type channels for supplying the plurality of charging currents to the plurality of ultrasonic transducers when the first drive voltage is applied to the gate, respectively. A plurality of second field-effect transistors that output a plurality of discharge currents from the plurality of ultrasonic transducers when the second drive voltage is applied to the gate, respectively. Field effect A plurality of first drivers that respectively turn on / off application of the first drive voltage to gates of the plurality of first field effect transistors, and gates of the plurality of second field effect transistors. A plurality of second drivers that respectively turn ON / OFF application of the second drive voltage to the first resistor, a third resistance element, and the first field effect transistor, and the first drive A voltage is applied to the gate, and the same characteristics as those of the third field-effect transistor, the fourth resistance element, and the second field-effect transistor in which a current generated in the third resistance element flows between the source and the drain And the second driving voltage is applied to the gate, and a fourth field-effect transistor that causes a current generated in the fourth resistance element to flow between the source and the drain. The first generation means sets the voltage value of the first drive voltage so that the current value of the current generated in the third resistance element becomes the first set value, and the second The generating means sets the voltage value of the second drive voltage so that the current value of the current generated in the fourth resistance element becomes the second set value.

  According to the present invention, the difference between the rise time and the fall time in an ultrasonic signal can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing the configuration of the ultrasonic diagnostic apparatus according to the first embodiment. In FIG. 1, the same parts as those in FIG. Further, FIG. 1 shows only the configuration related to the transmission of ultrasonic waves. In recent years, an ultrasonic diagnostic apparatus generally includes a two-dimensional array or a three-dimensional array of multichannel transducers and displays a tomographic image in real time. For this reason, the transmitting unit also has a corresponding number of channels, but FIG. 1 shows only one of them.

  The ultrasonic diagnostic apparatus according to the first embodiment includes an apparatus main body 100 and an ultrasonic probe 200.

  The apparatus main body 100 further includes a reference signal generator 21. The ultrasonic probe 200 further includes drivers 1 and 2, transistors 3 and 4, an ultrasonic transducer 5, resistance elements 6 and 7, a transmission waveform generator 8, constant current setting devices 9 and 10, resistance elements 11 and 12, transistors 13 and 14 and a current control unit 15.

  The reference signal generator 21 generates a reference signal. This reference signal is transmitted to the ultrasonic probe 200 via a signal line in a cable connecting the apparatus main body 100 and the ultrasonic probe 200. The reference signal is input to the transmission waveform generator 8.

  The driver 1 receives the signal S1 output from the transmission waveform generator 8, the voltage 2VHPH supplied via the power line PL1, and the voltage VCP output from the constant current setter 9. The driver 1 has a switch configuration for selecting voltages 2VHPH and VCP, and outputs a voltage 2VHPH when the signal S1 output from the transmission waveform generator 8 is L, and outputs a voltage VCP when it is H. The output voltage of the driver 1 is applied to the gate terminal of the transistor 3.

  The driver 2 receives the signal S2 output from the transmission waveform generator 8, the voltage 2VHNH supplied via the power line PL2, and the voltage VCN output from the constant current setter 10. The driver 2 has a switch configuration for selecting voltages 2VHNL and VCN, and outputs a voltage VCN when the signal S2 output from the transmission waveform generator 8 is L, and outputs a voltage 2VHNH when the signal S2 is H. The output voltage of the driver 2 is applied to the gate terminal of the transistor 4.

  As the transistor 3, a P-channel MOS FET is typically used. The drain terminal of the transistor 3 is connected to one of the terminals of the ultrasonic transducer 5. The source terminal of the transistor 3 is connected to one of the terminals of the resistance element 6.

  As the transistor 4, an N-type channel MOS type FET is typically used. The drain terminal of the transistor 4 is connected to one of the terminals of the ultrasonic transducer 5 in common with the drain terminal of the transistor 3. The source terminal of the transistor 4 is connected to one of the terminals of the resistance element 7.

  The ultrasonic transducer 5 is provided with a terminal to which the transistors 3 and 4 are not connected. The ultrasonic transducer 5 emits ultrasonic waves by being charged and discharged by the current supplied through the transistors 3 and 4.

  Resistive element 6 has a terminal connected to power line PL1 different from the source terminal of transistor 3 connected to. Resistive element 6 supplies a constant current from power line PL1 to the source terminal of transistor 3.

  The resistor element 7 has a terminal different from that connected to the source terminal of the transistor 4 connected to the power line PL2. Resistance element 7 supplies a constant current from power line PL2 to the source terminal of transistor 4.

  The transmission waveform generator 8 generates signals S1 and S2 each having a signal based on the reference signal. The signals S1 and S2 have different voltage values in the L state, but the time phases of the waveforms H and L are the same.

  The constant current setting device 9 has first to third input terminals. The first input terminal is directly connected to power line PL1. The second input terminal is connected to power line PL1 through resistance element 11. A set voltage output from the current control unit 15 is applied to the third input terminal. The constant current setter 9 generates a voltage VCP based on the voltages applied to these three input terminals.

  The constant current setting device 10 has first to third input terminals. The first input terminal is directly connected to power line PL2. The second input terminal is connected to power line PL2 through resistance element 12. A set voltage output from the current control unit 15 is applied to the third input terminal. The constant current setter 10 generates a voltage VCN based on the voltages applied to these three input terminals.

  Resistance element 11 generates a voltage drop corresponding to the magnitude of the current flowing out from power line PL1.

  Resistance element 12 generates a voltage drop corresponding to the magnitude of the current flowing out from power line PL2.

  As the transistor 13, an element having the same characteristics as the transistor 3 is used. The transistor 13 has a gate terminal connected to the output terminal of the constant current setter 9, a source terminal connected to the second input terminal of the constant current setter 9, and a drain terminal connected to the power line PL3.

  As the transistor 14, an element having the same characteristics as the transistor 4 is used. The transistor 14 has a gate terminal connected to the output terminal of the constant current setting device 10, a source terminal connected to the second input terminal of the constant current setting device 10, and a drain terminal connected to the power line PL4.

  The current control unit 15 gives a set voltage to each of the constant current setting devices 9 and 10. This set voltage can be changed to adjust the rise time and fall time of the voltage supplied to the ultrasonic transducer 5.

  FIG. 2 is a diagram illustrating a specific configuration example of the constant current setting unit 9.

  As shown in FIG. 2, the constant current setting device 9 includes operational amplifiers 9a and 9b.

  The non-inverting input terminal of the operational amplifier 9a corresponds to the first input terminal of the constant current setting device 9, and the inverting input terminal corresponds to the second input terminal. The output terminal of the operational amplifier 9a is connected to the non-inverting input terminal of the operational amplifier 9b. The inverting input terminal of the operational amplifier 9 b corresponds to the third input terminal of the constant current setting device 9. The output from the output terminal of the operational amplifier 9b is the voltage VCP.

  The constant current setter 10 also has a configuration similar to the configuration of the constant current setter 9 as described above.

  Next, the operation of the ultrasonic diagnostic apparatus configured as described above will be described.

  The transmission waveform generator 8 generates signals S1 and S2 having a transmission waveform based on the reference signal. These signals S1 and S2 are applied to the drivers 3 and 4, respectively.

  The driver 1 outputs a voltage 2VHPH when the signal S1 is L, and outputs a voltage VCP when the signal S1 is H. Thus, the voltage output from the driver 1 is applied to the gate terminal of the transistor 3. As the value of the voltage VCP, a voltage value necessary for turning on the transistor 3 is given. Therefore, when the signal S1 is H, the transistor 3 is turned on. When the transistor 3 is turned on, current is supplied from the power line PL1 to the ultrasonic transducer 5 via the resistance element 6 and the transistor 3, and the ultrasonic transducer 5 is charged.

  At this time, the magnitude of the current supplied to the ultrasonic transducer 5 is determined according to the magnitude of the drain current due to the gate-source voltage of the transistor 3. Since the voltage 2VHPH is only applied to the source terminal of the transistor 3 via the resistance element 6, the potential is always constant. Since the voltage VCP is applied to the gate terminal of the transistor 3 when the transistor 3 is turned on, the potential of the gate terminal in this state is determined by the voltage VCP.

  The voltage VCP is generated by the constant current setter 9 as described below.

  The voltage 2VHPL of the power line PL3 is set to a value lower than the gate voltage value of the transistor 13. Here, the voltage value across the resistance element 11 is detected by the operational amplifier 9 a of the constant current setter 9. Further, the operational amplifier 9b of the constant current setting device 9 generates the voltage VCP as a voltage having a value corresponding to the difference between the detected voltage value by the operational amplifier 9a and the set voltage value output from the current control unit 15. The constant current setter 9 has a high amplification factor, and negative feedback is applied through the transistor 13. Therefore, the voltage across the resistance element 11 is kept constant without being affected by the gate-source voltage of the transistor 13, that is, the magnitude of the current flowing between the resistance element 11 and the source-drain of the transistor 13 is kept constant. Thus, the value of the voltage VCP is adjusted. The voltage VCP adjusted in this way is applied to the gate terminal of the transistor 3, so that the voltage across the resistance element 6 is kept constant without being affected by the gate-source voltage of the transistor 3.

  On the other hand, the driver 2 outputs the voltage VCN when the signal S2 is L, and outputs the voltage 2VHNL when the signal S2 is H. Then, an output signal is applied to the gate terminal of the transistor 4. The transistor 4 is turned on when the waveform S2 is L, and is turned off when the waveform S2 is H. Thus, the voltage output from the driver 2 is applied to the gate terminal of the transistor 4. As the value of the voltage VCN, a voltage value necessary for turning on the transistor 4 is given. Therefore, when the signal S2 is L, the transistor 4 is turned on. When the transistor 4 is turned on, current is sucked from the ultrasonic vibrator 5 into the power line PL2, and the ultrasonic vibrator 5 is discharged.

  Similarly to the voltage VCP, the voltage VCN is also not affected by the voltage between the gate and the source of the transistor 14 by the constant current setting device 10, so that the voltage between the resistance elements 12 is constant, that is, between the drain and the source of the transistor 14. The value is adjusted so that the magnitude of the current flowing through the resistance element 12 is constant. By applying the voltage VCN adjusted in this way to the gate terminal of the transistor 4, the voltage across the resistance element 7 is kept constant at the same value as the voltage across the resistance element 6 without being affected by the gate-source voltage of the transistor 4. Maintained.

  Now, the signals S1 and S2 have the same time phases of the waveforms H and L. Therefore, only one of the transistors 3 and 4 is turned on as shown in FIG. Thus, charging and discharging of the ultrasonic transducer 5 as described above are executed at different timings. As a result, the waveform of the voltage supplied to the ultrasonic transducer 5 has a pulse shape as shown in FIG. The voltage between the resistance elements 6 when the transistor 3 is ON and the voltage between the resistance elements 7 when the transistor 4 is ON match, so that the voltage supplied to the ultrasonic transducer 5 is reduced. The rise time TL and the fall time TF in the waveform are equal to each other.

  As described above, according to the first embodiment, the ultrasonic vibrator 5 can be charged and discharged with a waveform having a very small difference between the rise time TL and the fall time TF. By using ultrasonic waves with high symmetry between the rise and fall obtained as a result, it becomes possible to detect the waveform distortion generated in the living body and obtain a very good harmonic image. It becomes possible.

  Note that the magnitude of the charging current of the ultrasonic transducer 5 depends on the magnitude of the current flowing between the source and drain of the resistance element 11 and the transistor 13 and the magnitude of the current flowing between the drain and source of the transistor 14 and the resistance element 12. And the magnitude of the discharge current are determined. The magnitude of the current flowing between the source and drain of the resistor element 11 and the transistor 13 and the magnitude of the current flowing between the drain and source of the transistor 14 and the resistor element 12 are set to the set voltage magnitude output by the current control unit 15. It depends on it. Therefore, the magnitude of the rise time TL and the magnitude of the fall time TF can be arbitrarily adjusted by the set voltage.

(Second Embodiment)
FIG. 4 is a configuration diagram in a case where an ultrasonic probe having a function equivalent to that of the ultrasonic probe 200 in the first embodiment is realized by applying an application-specific integrated circuit (ASIC). In FIG. 4, the same elements as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. Although FIG. 1 shows a configuration for one channel, FIG. 4 shows a multi-channel configuration having n ultrasonic transducers 5-1 to 5-n.

  The inside of the frame line denoted by reference numeral 210 in FIG. 4 is a portion configured by applying ASIC. Elements corresponding to the drivers 1 and 2, transistors 3 and 4, resistance elements 6 and 7, constant current setting devices 9 and 10, resistance elements 11 and 12, and transistors 13 and 14 in FIG. 1 are realized by applying the ASIC. .

  The pulsars 211-1 to 211-n correspond to the ultrasonic transducers 5-1 to 5-n, respectively. The pulsars 211-1 to 211-n have a common configuration, and include drivers 1 and 2, transistors 3 and 4, and resistance elements 6 and 7, respectively. The driver 1 is configured by connecting a transistor 1a, which is a P-channel MOS FET, and a transistor 1b, which is an N-channel MOS FET, in a class C operation in which drain terminals are connected to each other. The driver 2 is configured by connecting a transistor 2a, which is a P-type channel MOS type FET, and a transistor 2b, which is an N-type channel MOS type FET, in the same class C operation.

  The driver voltage generator 212 is provided in common with the pulsers 211-1 to 211-n. The driver voltage generator 212 includes operational amplifiers 9c and 10c, constant current circuits 9d and 10d, resistance elements 11a, 11b, 12a and 12b, and transistors 13 and 14. The operational amplifier 9c, the constant current circuit 9d, and the resistance elements 11a and 11b constitute a circuit having a function equivalent to that of the constant current setting device 9 and the resistance element 11 in the first embodiment. Further, the operational amplifier 10c, the constant current circuit 10d, and the resistance elements 12a and 12b constitute a circuit having a function equivalent to that of the constant current setting device 10 and the resistance element 12 in the first embodiment.

  The driver voltage generation unit 212 generates the same voltages VCP and VCN as in the first embodiment. These voltages VCP and VCN are commonly used in each of the pulsers 211-1 to 211-n.

  It is generally known that the element characteristics of the same configuration inside the ASIC can be very close. For this reason, as described above, the voltages VCP and VCN can be commonly used in each of the pulsars 211-1 to 211-n, and the circuit can be miniaturized.

  Of course, by turning on the transistors 3 and 4 with the voltages VCP and VCN, respectively, it is possible to transmit ultrasonic waves having high symmetry between rising and falling as described in the first embodiment.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a diagram showing a configuration of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. The figure which shows the specific structural example of the constant current setting device 9 in FIG. The figure which shows the operation state of the transistors 3 and 4 in FIG. 1, and the change of the terminal voltage of the ultrasonic transducer | vibrator 5. FIG. The block diagram in the case of implement | achieving the ultrasonic probe which has a function equivalent to the ultrasonic probe 200 in 1st Embodiment by applying ASIC. The figure which shows a part of circuit structure in the ultrasonic probe in the conventional ultrasonic diagnostic apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,2 ... Driver 1a, 1b, 2a, 2b, 3, 4, 13, 14 ... Transistor, 5,5-1-5-n ... Ultrasonic vibrator, 6, 7, 11, 12, 11a, 11b , 12a, 12b ... resistive elements, 8 ... transmission waveform generator, 9a, 9b, 9c, 10c ... operational amplifier, 9d, 10d ... constant current circuit, 9, 10 ... constant current setter, 15 ... current control unit, 21 Reference signal generator, 100, main body, 200, ultrasonic probe, 211-1 to 211-n, pulser, 212, driver voltage generator.

Claims (4)

In an ultrasonic diagnostic apparatus that diagnoses a subject using ultrasonic waves transmitted from an ultrasonic transducer,
First generating means for generating a first drive voltage;
Second generating means for generating a second drive voltage;
A first resistance element for generating a charging current for charging the ultrasonic vibrator;
A second resistance element for generating a discharge current for discharging the ultrasonic vibrator;
A P-channel first field effect transistor that supplies the charging current to the ultrasonic transducer when the first drive voltage is applied to a gate;
An N-channel second field effect transistor for outputting the discharge current from the ultrasonic transducer when the second drive voltage is applied to the gate;
A first driver for turning on / off application of the first drive voltage to a gate of the first field effect transistor;
A second driver for turning on / off application of the second drive voltage to the gate of the second field effect transistor;
A third resistance element;
A third field effect transistor having the same characteristics as the first field effect transistor, the first drive voltage being applied to the gate, and a current generated in the third resistance element flowing between a source and a drain; ,
A fourth resistance element;
A fourth field effect transistor having the same characteristics as the second field effect transistor, the second drive voltage being applied to the gate, and a current generated in the fourth resistance element flowing between a source and a drain; Comprising
The first generation means sets the voltage value of the first drive voltage so that the current value of the current generated in the third resistance element becomes the first set value,
The ultrasonic diagnostics characterized in that the second generation means sets the voltage value of the second drive voltage so that the current value of the current generated in the fourth resistance element becomes a second set value. apparatus. In an ultrasound diagnostic apparatus that diagnoses a subject using ultrasound transmitted from each of a plurality of ultrasound transducers,
First generating means for generating a first drive voltage;
Second generating means for generating a second drive voltage;
A plurality of first resistance elements for generating a charging current for charging each of the plurality of ultrasonic transducers;
A plurality of second resistance elements for generating discharge currents for discharging the plurality of ultrasonic transducers, respectively;
A plurality of P-channel first field-effect transistors that respectively supply a plurality of the charging currents to the plurality of ultrasonic transducers when the first driving voltage is applied to a gate;
A plurality of N-channel second field effect transistors that respectively output a plurality of discharge currents from the plurality of ultrasonic transducers when the second drive voltage is applied to a gate;
A plurality of first drivers that respectively turn on / off application of the first drive voltage to the gates of the plurality of first field effect transistors;
A plurality of second drivers that respectively turn ON / OFF application of the second drive voltage to the gates of the plurality of second field effect transistors;
A third resistance element;
A third field effect transistor having the same characteristics as the first field effect transistor, the first drive voltage being applied to the gate, and a current generated in the third resistance element flowing between a source and a drain; ,
A fourth resistance element;
A fourth field effect transistor having the same characteristics as the second field effect transistor, the second drive voltage being applied to the gate, and a current generated in the fourth resistance element flowing between a source and a drain; Comprising
The first generation means sets the voltage value of the first drive voltage so that the current value of the current generated in the third resistance element becomes the first set value,
The ultrasonic diagnostic, wherein the second generation means sets the voltage value of the second drive voltage so that the current value of the current generated in the fourth resistance element becomes a second set value. apparatus. An ultrasonic transducer,
First generating means for generating a first drive voltage;
Second generating means for generating a second drive voltage;
A first resistance element for generating a charging current for charging the ultrasonic vibrator;
A second resistance element for generating a discharge current for discharging the ultrasonic vibrator;
A P-channel first field effect transistor that supplies the charging current to the ultrasonic transducer when the first drive voltage is applied to a gate;
An N-channel second field effect transistor for outputting the discharge current from the ultrasonic transducer when the second drive voltage is applied to the gate;
A first driver for turning on / off application of the first drive voltage to a gate of the first field effect transistor;
A second driver for turning on / off application of the second drive voltage to the gate of the second field effect transistor;
A third resistance element;
A third field effect transistor having the same characteristics as the first field effect transistor, the first drive voltage being applied to the gate, and a current generated in the third resistance element flowing between a source and a drain; ,
A fourth resistance element;
A fourth field effect transistor having the same characteristics as the second field effect transistor, the second drive voltage being applied to the gate, and a current generated in the fourth resistance element flowing between a source and a drain; Comprising
The first generation means sets the voltage value of the first drive voltage so that the current value of the current generated in the third resistance element becomes the first set value,
The ultrasonic probe characterized in that the second generation means sets the voltage value of the second drive voltage so that the current value of the current generated in the fourth resistance element becomes a second set value. . A plurality of ultrasonic transducers;
First generating means for generating a first drive voltage;
Second generating means for generating a second drive voltage;
A plurality of first resistance elements for generating a charging current for charging each of the plurality of ultrasonic transducers;
A plurality of second resistance elements for generating discharge currents for discharging the plurality of ultrasonic transducers, respectively;
A plurality of P-channel first field-effect transistors that respectively supply a plurality of the charging currents to the plurality of ultrasonic transducers when the first driving voltage is applied to a gate;
A plurality of N-channel second field effect transistors that respectively output a plurality of discharge currents from the plurality of ultrasonic transducers when the second drive voltage is applied to a gate;
A plurality of first drivers that respectively turn on / off application of the first drive voltage to the gates of the plurality of first field effect transistors;
A plurality of second drivers that respectively turn ON / OFF application of the second drive voltage to the gates of the plurality of second field effect transistors;
A third resistance element;
A third field effect transistor having the same characteristics as the first field effect transistor, the first drive voltage being applied to the gate, and a current generated in the third resistance element flowing between a source and a drain; ,
A fourth resistance element;
A fourth field effect transistor having the same characteristics as the second field effect transistor, the second drive voltage being applied to the gate, and a current generated in the fourth resistance element flowing between a source and a drain; Comprising
The first generation means sets the voltage value of the first drive voltage so that the current value of the current generated in the third resistance element becomes the first set value,
The ultrasonic probe characterized in that the second generation means sets the voltage value of the second drive voltage so that the current value of the current generated in the fourth resistance element becomes a second set value. .

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