JP5138249B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus mainly used for medical purposes, and more particularly, an ultrasonic diagnostic apparatus including a transmission circuit that generates and transmits an arbitrary waveform voltage for driving an ultrasonic probe. About.

  A medical ultrasonic diagnostic apparatus irradiates a subject with ultrasonic waves from an ultrasonic probe, and based on an echo signal received through the ultrasonic probe, a two-dimensional ultrasonic image of the subject or A three-dimensional ultrasonic image is formed and displayed on a display device for diagnosis.

  The ultrasonic probe is configured to include a large number of ultrasonic transducers arranged in parallel, and each of these ultrasonic transducers inputs a drive signal from a transmission circuit arranged in an ultrasonic diagnostic apparatus. A pulse wave (PW) and a continuous wave (CW) are used as the voltage applied from the transmission circuit to the piezoelectric element of the ultrasonic probe depending on the purpose of diagnosis. .

The pulse wave is used in the B mode, the M mode, and the pulse Doppler mode. The number of transmitted pulses per one time is about several waves, and the amplitude of the transmitted pulse is a high voltage pulse of 150 Vpp or less.
On the other hand, the continuous wave is used in a continuous wave Doppler mode, and the amplitude of the continuous wave is a relatively low voltage of 10 Vpp or less.

  A transmission circuit that generates such a pulse wave and / or continuous wave and transmits these voltages to the ultrasonic probe is, for example, as disclosed in Patent Document 1 or Patent Document 2 below. The basic configuration is that a positive DC voltage (high voltage) is applied to the center tap of the primary winding of the pulse transformer in which the ultrasonic vibrator is connected to both ends of the secondary winding. A pulse voltage is generated in the primary winding by operating switching circuits provided at both ends of the primary winding.

The drive signal from such a transmission circuit, that is, the output signal from the secondary winding of the pulse transformer, is a rectangular wave having an amplitude substantially determined by the value of the DC voltage applied to the center tap of the primary winding. The frequency is determined by the alternating on / off frequency of each switching circuit provided at both ends of the primary winding.
JP-A-7-336198 JP 2001-57978

In recent years, ultrasonic diagnostic apparatuses are configured so as to be compatible with various diagnostic modes, and various types of ultrasonic probes that can be selectively used depending on a region to be imaged are prepared.
Furthermore, in order to cope with higher image quality and higher functionality, it is desired to increase the resolution and increase the S / N (signal / noise) ratio so that observation can be made deep.

In order to respond to such a request, a voltage of an arbitrary waveform is output from the transmission circuit according to the diagnostic mode or the type of the ultrasonic probe, and the transducer of the ultrasonic probe is output with this output voltage. Need to drive.
That is, the transmission circuit needs to arbitrarily output the amplitude, frequency, and waveform of the output voltage.

  However, since the output voltage of the transmission circuit disclosed in Patent Documents 1 and 2 is a rectangular wave and the amplitude cannot be varied, it is not possible to meet the above requirements.

The present invention aims at providing an arbitrary amplitude, the voltage of the frequency and the waveform can be output and ultrasonic diagnostic apparatus having a transmitting circuit that can be power saving.

To achieve the above object, the ultrasonic diagnostic apparatus of the present invention includes a DC power supply provided in the side of the pulse transformer input winding, and a semiconductor power conversion means by the semiconductor switching means is controlled by the semiconductor power conversion means A transmission circuit that inputs the input power to the input winding, extracts the input power from the output winding side of the pulse transformer, and supplies the input power to the transducer of the ultrasonic probe. The transmission circuit includes a constant current source provided with a current control means for controlling the current flowing in the input winding of the pulse transformer to a constant value, and a control signal for controlling the current of the constant current source. A linear amplifier configured to provide a current control signal generating means for generating a negative feedback means for negatively feeding back the current controlled by the constant current source to the semiconductor power conversion means, and an input to the linear amplifier And an arbitrary waveform control signal generating means for generating a control signal for controlling the driving voltage of the vibrator to an arbitrary waveform, and the arbitrary waveform control signal generating means controls the driving voltage of the vibrator to an arbitrary waveform. An arbitrary waveform data storage means for storing digital data of the relationship between time and amplitude for performing, a first digital / analog conversion means for converting the arbitrary waveform data from the arbitrary waveform data storage means to an analog value, Complementary signal generating means for generating a complementary signal for complementary conduction control of the first semiconductor switching means and the second semiconductor switching means from the output signal of the first digital / analog converting means, The current control signal generating means includes constant current control data storage means for storing digital data for controlling the current of the constant current source, and A second digital / analog converting means for converting digital data from the current control data storage means into an analog value; timing for reading the data of the arbitrary waveform data storage means and the data of the constant current control data storage means; and the first The current control signal generating means is operated in conjunction with the arbitrary waveform control signal generating means in synchronism with the conversion timing of the digital / analog converting means and the second digital / analog converting means. And a transmission timing signal generating means for stopping the constant current source except when the slave drive voltage is transmitted .

ADVANTAGE OF THE INVENTION According to this invention, the ultrasonic diagnosing device provided with the transmission circuit which can output the voltage of arbitrary amplitude, a frequency, and a waveform and can aim at power saving can be provided.

Hereinafter, preferred embodiments of an ultrasonic diagnostic apparatus of the present invention will be described in detail with reference to the accompanying drawings.
Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment of the present invention, and the repetitive description thereof will be omitted.

First Embodiment
FIG. 1 is a schematic configuration diagram showing a first embodiment of an ultrasonic diagnostic apparatus according to the present invention. This ultrasonic diagnostic apparatus generates a voltage for driving a control unit 1 that controls the entire apparatus, an operation unit 2 that inputs various operation signals and performs operations, and a transducer of an ultrasonic probe Ultrasonic transducer drive voltage generation circuit 3, a transmission unit 4 that transmits the drive voltage generated by the ultrasonic transducer drive voltage generation circuit 3 to the ultrasonic probe, and a drive voltage transmitted from the transmission unit 4 A receiving unit 5 for receiving an echo signal generated based on the above, an ultrasonic probe 6 composed of the transmitting unit 4, the receiving unit 5 and an ultrasonic transducer (not shown), and supplying operating power to the apparatus A power supply unit 7 that performs processing of the echo signal received by the receiving unit 5 to generate an ultrasonic image, and an image generation unit 8, and an ultrasonic image and diagnosis generated by the signal processing and image generation unit 8 Display unit 9 for displaying results and the like, and recording for recording the ultrasonic images and diagnosis results Configured to include a location 10.

  In the ultrasonic diagnostic apparatus having such a configuration, the ultrasonic transducer drive voltage generation circuit 3 and the transmission unit 4 constitute a transmission circuit 11 that is a main part of the present invention, and a specific circuit configuration thereof is shown in FIG. Shown in

  In FIG. 2, the transmission circuit 11 includes a main circuit 20 that generates a voltage for driving the ultrasonic transducer 6a that is a load, and a control circuit 21 that generates a control signal for controlling the main circuit 20. The control circuit 21 includes an arbitrary waveform control signal generation circuit 21a (arbitrary waveform control signal generation means) and a current control signal generation circuit 21B (current control signal generation means).

  The main circuit 20 includes a pulse transformer 20a having two primary windings 20a1 and 20a2 and a secondary winding 20a3, a winding start of the primary winding 20a1 and a winding end of the primary winding 20a2 of the pulse transformer 20a. DC power source 20B connected as shown in the figure supplied from the power supply unit 7 in FIG. 1 between this connection point and the ground, the end of the primary winding 20a1 of the pulse transformer 20a and the winding of the primary winding 20a2 First, by two sets of N-channel MOS field effect transistors MOSFET (Metal-Oxide SeMiconductor Field Effect Transistor) M1 (first semiconductor switching means) and M2 (second semiconductor switching means) connected to each drain D A switching part 20c (semiconductor power conversion means), a constant current source 20d connected between the connection point between the sources S of the two sets of MOSFET M1 and MOSFET M2 of the switching part 20c and the ground, and a drain D and a gate of the MOSFET M1 G and the drain D and gate of the MOSFET M2 A series connection body (negative feedback means) of a feedback resistor Rf and a feedback capacitor Cf respectively connected between the gates G, and an input resistor Ri connected to each of the gate G of the MOSFET M1 and the gate G of the MOSFET M2, In this configuration, the transducer 6a of the ultrasonic probe as a load is connected to the secondary winding 20a3 of the pulse transformer 20a, and one end of the transducer 6a is grounded.

In this configuration, a feedback loop is formed by the input resistor Ri and the feedback resistor Rf, and a direct current component is cut by the feedback capacitor Cf to feed back only the alternating current component, thereby operating as a linear amplifier.
The gain of the linear amplifier configured as described above is determined by the ratio of the input resistance Ri and the feedback resistance Rf and becomes constant because the MOSFET M1 and MOSFET M2 have large gains.

  In order to operate as a linear amplifier as described above, it is necessary to operate the MOSFET M1 and the MOSFET M2 in an active region without saturating the MOSFET M1 and the MOSFET M2 from the voltage of the DC power supply 20B. However, a sufficiently high withstand voltage is required.

  Input signals (complementary pulses) CKP and CKN with different timings of conduction (ON) and non-conduction (OFF) are input to the gates of the MOSFET M1 and the MOSFET M2, respectively. Are complementarily turned on and off alternately so that current flows alternately through the primary windings 20a1 and 20a2 of the pulse transformer 20a.

  On the other hand, positive and negative voltages are output to the secondary winding 20a3 of the pulse transformer 20a as a result of the alternating current flowing through the primary windings 20a1 and 20a2, and are applied to the ultrasonic probe 6a.

  The pulse transformer may have a configuration in which the primary winding has a center tap, a DC power source is connected between the center tap and the ground, and MOSFET M1 and MOSFET M2 are connected to both ends of the primary winding.

  Arbitrary waveform control signal generating circuit 21a (arbitrary waveform control signal generating means) for driving and controlling MOSFET M1 and MOSFET M2 of main circuit 20 configured in this way is a switching drive control for MOSFET M1 and MOSFET M2 of switching unit 20c of main circuit 20 Arbitrary waveform data memory 21a1 (arbitrary waveform data storage means) for storing an arbitrary waveform control signal for performing, and a D / A converter 21a21 for converting a digital signal read from the arbitrary waveform data memory 21a1 into an analog signal ( A complementary signal generating circuit 21a2 (complementary signal generating means) composed of a first digital / analog converting means) and a differential amplifier 21a22 that differentially amplifies the analog signal converted by the D / A converter 21a21; MOSFET driving circuit 20c (20c1, 20c2) that amplifies the complementary signal output from complementary signal generating circuit 21a2 to voltages (complementary pulses CKP, CKN) that can drive MOSFET M1 and MOSFET M2 That.

  FIG. 3 shows a specific configuration example of the constant current source 20d. The constant current source 20d includes an N-channel MOS field effect transistor MOSFET M3 (third switching means), a resistor Re connected between the MOSFET M3 and the ground, and a drain current of the MOSFET M3, that is, the ultrasonic transducer. The output current of the constant current source 20d is fed back so that the current flowing through 6a becomes a current proportional to the current control signal output from the current control signal generation circuit 21B, and control is performed from this feedback signal and the current control signal. An operational amplifier OPA for calculating a deviation is provided, and the MOSFET M3 is controlled to be switched by the output voltage of the operational amplifier OPA so that the drain current of the MOSFET M3 becomes a constant current.

  A current control signal generating circuit 21B (current control signal generating means) that generates a signal for controlling the current of the constant current source 20d is a current control that stores a current control signal for controlling the current I0 of the constant current source 20d. A waveform data memory 21B1 (constant current control data storage means), a D / A converter (second digital / analog conversion means) for converting a digital signal read from the current control waveform data memory 21B1 into an analog signal; It is configured with.

  The output voltage of the transmission circuit 11 configured as described above, that is, the voltage for driving the ultrasonic transducer 6a that is a load, is determined by the ratio of the feedback loops Ri and Rf regardless of the current Io, and the It has a frequency determined by the operating frequency of MOSFETM1 and MOSFETM2.

  The data to be stored in the arbitrary waveform data memory 21a1 is data of the relationship between time and voltage amplitude, and this data is read out and fixed by the D / A converter 21a21 of the complementary signal generation circuit 21a2. Each time interval is converted to an analog value, a control signal for the vibrator driving voltage is generated.

  On the other hand, the data stored in the current control waveform data memory 21B1 is digital data for controlling the current I0 of the constant current source 20d, and this data is read out to perform D / A conversion of the current control signal generation circuit 21B. A signal for controlling the current I0 of the constant current source 20d is generated by the converter 21B2 by converting into an analog value.

  Therefore, by controlling the current Io of the constant current source 20d, it is possible to reduce power consumption such as flowing a current only during an ultrasonic wave transmission period.

Next, the operation of the transmission circuit 11 configured as described above will be described.
Here, a case where a sinusoidal AC voltage is output as an arbitrary waveform will be described as an example, and a description will be given with reference to waveform diagrams of each part appended to FIG.

  When an operation command is input from the operation unit 2 to the control unit 1 in FIG. 1, the arbitrary waveform control is performed from the transmission waveform timing signal generation unit 1a (transmission timing signal generation unit) provided in the control unit 1. Timing signal for reading digital data from the arbitrary waveform data memory 21a1 of the signal generation circuit 21a and the current control waveform data memory 21B1 of the current control signal generation circuit 21B, and the D / A of the D / A converter 21a21 and the D / A converter 21B2 The conversion timing signal is output in synchronization, and the transmission circuit 11 starts operation.

When the read timing signal is output, digital data is read from the arbitrary waveform data memory 21a1 and input to the complementary signal generation circuit 21a2, and this input digital data is converted to an analog value by the D / A converter 21a21. Further, a complementary signal is generated by the differential amplifier 21a22, which is amplified by the MOSFET drive circuit 20c (20c1, 20c2) to generate the MOSFET drive voltage shown in the waveform diagrams <1> and <2> of FIG. .
At the same time, digital data is read from the current control waveform data memory 21B1 and input to the D / A converter 21B2, and a current control signal for the constant current source 20d is generated.

  When the MOSFET drive voltage amplified by the MOSFET drive circuit 20c (20c1, 20c2) is applied to the gates of the MOSFET M1 and the MOSFET M2 through the input resistor Ri, the MOSFET M1 and the MOSFET M2 are sine waves corresponding to the data of the arbitrary waveform data memory 21a1. The currents shown in <3> and <4> in FIG. 2 flow through the primary windings 20a1 and 20a2 of the pulse transformer 20a which are alternately turned on every half cycle of the frequency of the AC voltage.

  By cutting the direct current component of the current flowing through the primary windings 20a1 and 20a2 with the feedback capacitor Cf and feeding back only the alternating current component through the feedback resistor Rf, the ratio of the input resistance Ri and the feedback resistance Rf is obtained. The MOSFET M1 and the MOSFET M2 operate as a linear amplifier having a gain, and the MOSFET M1 and the MOSFET M2 are subjected to switching control so that the waveform of the current flowing through the secondary winding 20a3 becomes a waveform output from the arbitrary waveform data memory 21a.

  The current flowing through the primary windings 20a1 and 20a2 becomes a constant current by switching the MOSFET M3 of the constant current source 20d, and as a result, the output voltage of the transmission circuit of the first embodiment is an arbitrary waveform data memory 21a. The voltage shown in <5> of FIG. 2 is proportional to the voltage waveform stored in.

When a pulse wave or a continuous wave is transmitted from the transmission circuit configured as described above, the DC power supply 20B may be configured as follows.
That is, when transmitting a pulse wave, a pulse wave of 150 Vpp or less is required, so a high-voltage power supply of about 100 V is used, and when transmitting a continuous wave, its amplitude is 10 Vpp or less, so about 10 to 20 V The low voltage power supply can be used.

  As described above, the transmission circuit 11 according to the first embodiment of the present invention includes the pulse transformer, the DC power supply, the switching circuit, and the negative feedback means for negatively feeding back the AC current flowing through the input winding of the pulse transformer. Since the linear amplifier is configured and this linear amplifier is controlled by an arbitrary waveform control signal, it is possible to output a voltage having an arbitrary amplitude, frequency, and waveform while using a pulse transformer system with a simple circuit configuration.

  Furthermore, unlike the conventional method, the amplitude of the output voltage is not affected by the impedance of the load, so the linearity as a linear amplifier is improved.

  These make it possible to support various diagnostic modes and select and use various types of ultrasonic probes, with high resolution and high S / N (signal / noise) to cope with higher image quality and higher functionality. It will contribute to the transformation.

  In addition, since it operates as a linear amplifier, the harmonic component of the ultrasonic signal irradiated to the subject is reduced by making the data stored in the arbitrary waveform data memory 21a1 data that does not generate harmonics in the output voltage. , Image quality in a new ultrasonic imaging method called harmonic imaging that prevents the generation of heat in the living body due to ultrasonic irradiation, and the recent nonlinear effects of microbubbles, or the nonlinear effects of ultrasonic propagation in the subject It will also contribute to the improvement of

The timing signal for reading digital data from the arbitrary waveform data memory 21a1 and the current control waveform data memory 21B1 is synchronized with the D / A conversion timing signal of the D / A converter 21a21 and the D / A converter 21B2. The control signal generation circuit 21B is operated in conjunction with the arbitrary waveform control signal generation circuit 21a, and the constant current source 20d is stopped except when the ultrasonic transducer drive voltage is transmitted. Can be achieved.
Therefore, since the power supply capacity of the ultrasonic diagnostic apparatus can be reduced, the ultrasonic diagnostic apparatus equipped with this power supply becomes small and light, and contributes to the improvement of portability.

<< Second Embodiment >>
FIG. 4 is an overall configuration diagram of an ultrasonic diagnostic apparatus according to a second embodiment of the present invention in which a pulse wave and a continuous wave transmission circuit are shared.
The ultrasonic diagnostic apparatus shown in FIG. 4 includes a newly added power supply control unit 12, a power supply unit 7 ′, an ultrasonic transducer drive voltage generation circuit 3 ′, and this ultrasonic transducer drive voltage generation circuit 3 ′. 1 is different from the first embodiment shown in FIG. 1 and the rest is the same as in FIG. 1, and the description of this part is omitted.

  In FIG. 4, the power supply unit 7 ′ includes two DC power supplies, ie, a high-voltage DC power supply HV for generating pulse waves and a low-voltage power supply LV for generating continuous waves, as DC power supplies for the ultrasonic transducer drive voltage generating circuit 3 ′. These DC power supplies are switched between when a pulse wave is generated and when a continuous wave is generated by a changeover switch 13 (power supply switching means) of the power supply control unit 12 and supplied to the ultrasonic transducer drive voltage generation circuit 3 ′.

  As shown in FIG. 5, the ultrasonic vibrator drive voltage generation circuit 3 ′ includes a DC power supply 20B ′ including a high voltage power supply HV and a low voltage power supply LV supplied from the power supply unit 7 ′. The circuit is the same as that of FIG. 2 of the first embodiment.

  In the ultrasonic transducer drive voltage generation circuit 3 ′ having this configuration, the data for pulse wave generation and continuous wave generation are stored in the arbitrary waveform data memory 21a1 and the current control waveform data memory 21B1, and are continuously generated at the time of pulse generation. When the wave is generated, data corresponding to these are read out and operated in the same manner as in FIG. 2 to output an arbitrary waveform voltage to drive the ultrasonic transducer 6a.

  The switching of the DC power supply 20B ′ is performed by a transmission signal determination unit 1B of the control unit 1 according to an operation command from the operation unit 2 in FIG. 2 to determine whether the transmission is a pulse wave or a continuous wave transmission (power switching control means Then, the changeover switch 13 is switched by this determination signal to obtain a DC power source corresponding to the operation command.

  As described above, also in the ultrasonic diagnostic apparatus including the transmission circuit that transmits the pulse wave and the continuous wave, the same effect as the first embodiment can be obtained, and the ultrasonic transducer driving of the transmission circuit can be performed. Since the voltage generation circuit can be used for both pulse wave transmission and continuous wave transmission, the circuit becomes smaller and the portability, which is one of the features of the ultrasonic diagnostic apparatus, is improved.

  As mentioned above, although various embodiment was described about this invention, this invention is not limited to these embodiment, In the range which does not deviate from the summary of this invention, it can change variously as follows.

  For example, to change the gain of the linear amplifier between pulse wave transmission and continuous wave transmission, a linear amplifier gain changeover switch is provided, and the input resistance Ri is set between the pulse wave transmission and the continuous wave transmission. A value corresponding to the gain may be used, and the input resistance Ri may be switched by the linear amplifier gain changeover switch (input resistance changeover means, gain changeover control means).

  In addition, when using a probe that operates with a pulse wave or continuous wave with a low gain and a probe that operates with a pulse wave or continuous wave with a high gain, depending on the diagnostic application, a gain similar to that described above can be used. Should be switched.

Further, in the circuits shown in FIGS. 2, 3, and 5, examples are shown in which MOS field effect transistors, which are self-extinguishing elements, are used as the switching elements M1, M2, and M3. However, other switching elements may be used as long as they have similar functions.

  The input control signal for outputting an arbitrary waveform is stored in the arbitrary waveform data memory 21a1 and the current control waveform data memory 21B1, and these data are read and converted into analog values. The present invention is not limited to this, and any control signal having an arbitrary waveform may be output using an analog circuit as long as it can output a control signal having an arbitrary waveform.

1 is a schematic configuration diagram showing a first embodiment of an ultrasonic diagnostic apparatus according to the present invention. The circuit block diagram of the transmission circuit in the 1st Embodiment of this invention. The specific block diagram of the constant current source in the 1st Embodiment of this invention. FIG. 5 is an overall configuration diagram of an ultrasonic diagnostic apparatus according to a second embodiment of the present invention in which pulse wave and continuous wave transmission circuits are shared. FIG. 5 is a circuit configuration diagram of a transmission circuit according to a second embodiment of the present invention.

Explanation of symbols

1 Control unit, 1a Transmitted waveform timing signal generator, 1B Transmitted signal discriminator, 3, 3 'ultrasonic transducer drive voltage generator, 4 Transmitter, 6 Ultrasonic probe, 6a Ultrasonic probe Oscillator, 7, 7 'power supply unit, 11, 11' transmission circuit, 12 power supply control unit, 13 power supply switch, 20 main circuit, 20a pulse transformer, 20a1, 20a2 pulse transformer primary winding, 20a3 pulse transformer Secondary winding, 20B DC power supply, 20c switching unit, 20d constant current source, 21 control circuit, 21a arbitrary waveform control signal generation circuit, 21a1 arbitrary waveform data memory, 21a2 complementary signal generation circuit, 21a21 D / A converter, 21a22 Differential amplifier, 21B1 Current control waveform data memory, 21B2 D / A converter, M1, M2, M3 MOS field effect transistor, Ri input resistance, Rf feedback resistor, Cf feedback capacitor, HV DC high voltage power supply, LV DC Constant voltage power supply, OPA operational amplifier

Claims (7)

A DC power supply provided in the side of the pulse transformer input winding,
Semiconductor power conversion means by semiconductor switching means;
A transmission circuit that inputs power controlled by the semiconductor power conversion means to the input winding, extracts the input power from the output winding side of the pulse transformer, and supplies it to the transducer of the ultrasonic probe An ultrasonic diagnostic apparatus comprising:
The transmission circuit includes a constant current source having a current control means for controlling the current flowing in the input winding of the pulse transformer to be constant;
Current control signal generating means for generating a control signal for controlling the current of the constant current source;
A linear amplifier configured by providing negative feedback means for negatively feeding back the current controlled by the constant current source to the semiconductor power conversion means, and input to the linear amplifier to control the drive voltage of the vibrator to an arbitrary waveform. An arbitrary waveform control signal generating means for generating a control signal for
The arbitrary waveform control signal generating means, arbitrary waveform data storage means for storing digital data of the relationship between time and amplitude for controlling the driving voltage of the vibrator to an arbitrary waveform,
First digital / analog conversion means for converting arbitrary waveform data from the arbitrary waveform data storage means into an analog value, and first semiconductor switching means and second output from the output signal of the first digital / analog conversion means. Complementary signal generation means for generating a complementary signal for complementary conduction control with the semiconductor switching means,
The current control signal generating means is a constant current control data storage means for storing digital data for controlling the current of the constant current source, and a first converter for converting the digital data from the constant current control data storage means into an analog value. Two digital / analog conversion means;
The timing of reading the data of the arbitrary waveform data storage means and the data of the constant current control data storage means is synchronized with the conversion timing of the first digital / analog conversion means and the second digital / analog conversion means. A transmission timing signal generating means for operating the current control signal generating means in conjunction with the arbitrary waveform control signal generating means to stop the constant current source except when an ultrasonic transducer drive voltage is transmitted; An ultrasonic diagnostic apparatus comprising:   2. The ultrasonic diagnostic apparatus according to claim 1, wherein the negative feedback means is formed by connecting a series connection body of a feedback resistor and a feedback capacitor between an output and an input of the linear amplifier. The pulse transformer is a pulse transformer having two primary windings or a primary winding with a center tap, between the connection point connecting the two primary windings in series and ground, or between the center tap and ground. the DC power source connected to said semiconductor switching means, the first semiconductor switching means and the second semiconductor switching means across the ends or center tapped primary winding of the connected two primary windings in the series And the constant current source is connected between the connection point of the first semiconductor switching means and the second semiconductor switching means and the ground. Item 3. The ultrasonic diagnostic apparatus according to Item 1 or 2.   The constant current source includes at least a third semiconductor switching unit, a resistor connected between the outflow end of the current flowing through the third semiconductor switching unit and the ground, and a negative feedback of the current flowing through the input winding of the pulse transformer. And an operational amplifier for calculating a control deviation from the negative feedback signal and the current control signal from the current control signal generating means and outputting a control signal for controlling the switching of the third switching means. The ultrasonic diagnostic apparatus according to any one of claims 1 to 3. The ultrasonic diagnostic apparatus according to claim 1, wherein a differential amplifier is used as the complementary signal generation unit. The DC power source includes two sets of DC power sources, a high voltage power source and a low voltage power source, a power source switching means for switching between the two sets of DC power sources, and the power source switching means when the pulse wave is output to the high voltage power source, 5. The ultrasonic diagnostic apparatus according to claim 1, further comprising a power supply switching control unit configured to control to switch to the low-voltage power supply during continuous wave output. The input resistance switching means for switching the input resistance of the linear amplifier, and the gain switching control means for switching the input resistance by the input resistance switching means to switch the gain of the linear amplifier. The ultrasonic diagnostic apparatus according to any one of 1 to 6.

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