JP6793043B2 - Ultrasonic oscillator transmission circuit, ultrasonic probe, and ultrasonic diagnostic equipment - Google Patents

Description

The present invention relates to a transmission circuit for an ultrasonic probe and an ultrasonic diagnostic apparatus.

Patent Documents 1 to 3 show a technique of a transmission circuit for driving an ultrasonic oscillator in an ultrasonic diagnostic apparatus. The transmission circuit of Patent Document 1 converts a digital signal from a digital waveform generator into an analog signal by a digital-to-analog converter (referred to as DAC in the specification), amplifies it by an amplifier circuit, and then turns it into an ultrasonic transducer. Apply. The transmission circuit of Patent Document 2 converts a digital control signal output from a waveform generator at a predetermined timing into an analog signal to be a current signal by a current DAC, and applies it to an ultrasonic transducer.

The transmission circuit of Patent Document 3 uses a DAC, an amplifier circuit, or the like to apply a transmission signal having characteristics similar to those of a high-voltage single pulse to an ultrasonic vibrator. The waveform shape of the transmitted signal is a slow-moving portion that gradually changes between the baseline and the offset level of one polarity, an impulse portion that crosses the baseline from the offset level of one polarity and enters the other polarity, and the other polarity. It has a slow-moving portion that slowly changes between the offset level and the baseline.

Japanese Unexamined Patent Publication No. 2003-275203 Japanese Unexamined Patent Publication No. 2012-176235 Japanese Unexamined Patent Publication No. 2008-43721

Ultrasound diagnostic equipment is required to have high-sensitivity and high-resolution diagnostic images. As a technique for that purpose, for example, it is useful to use a transmission signal (referred to as a high voltage single wave transmission signal in the specification) as shown in Patent Document 3. The high-voltage single-wave transmission signal becomes a substantially impulse signal by changing the slow-moving portion at a frequency outside the band of the ultrasonic vibrator, and as a result, the distance resolution can be improved.

Here, as the circuit system of the transmission circuit for generating the transmission signal, a pulsar system and a linear system can be mentioned. The pulsar type transmission circuit has a circuit configuration that generates a square wave, and current flows only at the time of state transition, so that power consumption can be suppressed. However, since the circuit cannot generate an arbitrary waveform, it may be difficult to generate a high-voltage single-wave transmission signal itself. The linear transmission circuit is, for example, a circuit as shown in Patent Document 1 and Patent Document 3, and can generate an arbitrary waveform by DAC, so that a high voltage single wave transmission signal can be generated. However, the circuit may consume a large amount of power due to the standby current.

On the other hand, when a transmission circuit provided with a current DAC as shown in Patent Document 2 is used, it is possible to suppress power consumption to some extent by turning off the current when there is no signal, for example. However, since the circuit of Patent Document 2 essentially uses the control method by DAC as in Patent Document 1 and Patent Document 3, it is necessary to generate a digital signal with high frequency, and the control becomes complicated. Is a concern.

The present invention has been made in view of the above, and one of the objects thereof is an ultrasonic transducer transmission circuit, an ultrasonic probe, which can generate a high voltage single wave transmission signal with simple control. And to provide an ultrasonic diagnostic device.

The above and other objects and novel features of the present invention will become apparent from the description and accompanying drawings herein.

A brief description of typical embodiments of the inventions disclosed in the present application is as follows.

The transmission circuit of the ultrasonic vibrator of one embodiment includes a positive electrode drive circuit, a negative electrode drive circuit, and a reference drive circuit. The positive electrode drive circuit drives the drive input terminal of the ultrasonic transducer toward the positive electrode power supply by a drive current based on the first variable current source during the on period of the first switch. The negative electrode drive circuit drives the drive input terminal toward the negative electrode power supply by a drive current based on the second variable current source during the on period of the second switch. The reference drive circuit drives the drive input terminal toward the reference power supply.

According to the above embodiment, a high voltage single wave transmission signal can be generated with simple control.

It is a circuit diagram which shows the schematic structure example of the main part in the transmission circuit of the ultrasonic oscillator according to Embodiment 1 of this invention. It is a waveform diagram which shows an example of the generation operation of a high voltage single wave transmission signal in the transmission circuit of FIG. It is a waveform diagram which shows another example of the generation operation of a high voltage single wave transmission signal in the transmission circuit of FIG. FIG. 5 is a waveform diagram showing still another example of the operation of generating a high voltage single wave transmission signal in the transmission circuit of FIG. It is a waveform diagram which shows an example of the generation operation of a rectangular wave signal in the transmission circuit of FIG. It is a circuit diagram which shows the detailed configuration example of the transmission circuit of FIG. It is a circuit diagram which shows the detailed configuration example of the current value setting circuit in FIG. It is the schematic which shows the structural example of the ultrasonic diagnostic apparatus according to Embodiment 1 of this invention. It is a circuit diagram which shows the schematic structure example of the main part in the transmission circuit of the ultrasonic oscillator according to Embodiment 2 of this invention. FIG. 5 is a waveform diagram showing an example of a high-voltage single-wave transmission signal generation operation in the transmission circuit of FIG. It is the schematic which shows the structural example of the ultrasonic diagnostic apparatus according to Embodiment 3 of this invention. It is the schematic which shows the structural example of the 2D array IC in FIG. It is the schematic which shows the structural example of a part of the control circuit in FIG. It is a waveform diagram which shows the schematic operation example of the 2D array IC of FIG.

In the following embodiments, when necessary for convenience, the description will be divided into a plurality of sections or embodiments, but unless otherwise specified, they are not unrelated to each other, and one is the other. There is a relationship of some or all modifications, details, supplementary explanations, etc. In addition, in the following embodiments, when the number of elements (including the number, numerical value, quantity, range, etc.) is referred to, when it is specified in particular, or when it is clearly limited to a specific number in principle, etc. Except, the number is not limited to the specific number, and may be more than or less than the specific number.

Furthermore, in the following embodiments, the components (including element steps, etc.) are not necessarily essential unless otherwise specified or clearly considered to be essential in principle. Needless to say. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc. of a component or the like, the shape is substantially the same unless otherwise specified or when it is considered that it is not apparent in principle. Etc., etc. shall be included. This also applies to the above numerical values and ranges.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in all the drawings for explaining the embodiment, in principle, the same members are designated by the same reference numerals, and the repeated description thereof will be omitted.

(Embodiment 1)
The ultrasonic diagnostic apparatus is widely used as a medical diagnostic apparatus capable of non-invasive and real-time observation. Further, in recent years, in addition to the conventional two-dimensional image, a three-dimensional stereoscopic image and the like can be displayed, and the applications are steadily expanding. On the other hand, the image quality is lower than that of the X-ray CT (Computed Tomography) apparatus and the MRI (Magnetic Resonance Imaging) apparatus, so that the image quality is required to be higher than before. Hereinafter, embodiments will be described assuming application to such an ultrasonic diagnostic apparatus.

<< Outline configuration of transmission circuit >>
FIG. 1 is a circuit diagram showing a schematic configuration example of a main part in the transmission circuit of the ultrasonic oscillator according to the first embodiment of the present invention. The transmission circuit 1 shown in FIG. 1 includes a positive electrode drive circuit 2a, a negative electrode drive circuit 2b, and a reference drive circuit 3, and outputs a desired transmission signal to the drive input terminal 7 of the ultrasonic vibrator 4. .. The ultrasonic oscillator 4 generates ultrasonic waves in response to the transmission signal. The positive electrode drive circuit 2a includes a variable current source 10a and a switch 13a, and drives the drive input terminal 7 toward the positive electrode power supply H VDD by a drive current based on the variable current source 10a during the on period of the switch 13a. The negative electrode drive circuit 2b includes a variable current source 10b and a switch 13b, and drives the drive input terminal 7 toward the negative electrode power supply HVSS by a drive current based on the variable current source 10b during the on period of the switch 13b.

The reference drive circuit 3 drives the drive input terminal 7 toward the reference power supply (baseline) GND that serves as a reference for the positive electrode power supply H VDD and the negative electrode power supply HVSS. In this example, the reference drive circuit 3 includes variable current sources 11a, 11b and switches 14a, 14b, and the drive input terminal 7 is driven by a drive current based on the variable current sources 11a, 11b during the on period of switches 14a, 14b. Drive toward the reference power supply GND.

Specifically, the switch 14a is a switch that charges the voltage of the drive input terminal 7 to the level of the reference power supply GND, and the variable current source 11a determines the charging current value thereof. On the other hand, the switch 14b is a switch that discharges the voltage of the drive input terminal 7 to the level of the reference power supply GND, and the variable current source 11b determines the discharge current value. Although not particularly limited, for example, the reference power supply GND is 0V, the positive electrode power supply H VDD is + 100V or the like, and the negative electrode power supply HVSS is −100V or the like.

<< Operation of transmission circuit >>
FIG. 2 is a waveform diagram showing an example of a high-voltage single-wave transmission signal generation operation in the transmission circuit of FIG. First, in the transmission circuit 1, at time t1 to t2, the positive electrode drive circuit 2a is used to set the voltage of the drive input terminal 7 from the reference power supply GND to the positive electrode power supply H VDD to a frequency outside the band of the ultrasonic transducer 4. The pre-processing for transitioning with the first inclination is executed. Specifically, the transmission circuit 1 sets the variable current sources 10a, 10b, 11a, 11b to the inclination setting current value I1 at time t1. In this state, the transmission circuit 1 controls the switch 13a to be turned on. As a result, the voltage applied to the ultrasonic transducer 4 gradually rises with the first inclination toward the positive electrode power supply H VDD.

Subsequently, the transmission circuit 1 sets the variable current sources 10a, 10b, 11a, 11b to a pulse current value I2 larger than the inclination setting current value I1 at time t2. Here, the inclination setting current value I1 is expressed by the equation (assuming that the offset voltage (potential difference between H VDD and GND) is "V", the transition time is "t", and the capacitance value of the ultrasonic vibrator 4 is "C". It becomes 1). “V” and “C” are default values, and the transition time “t” is the frequency at which the slope (first slope) of the voltage applied to the ultrasonic vibrator 4 is outside the band of the ultrasonic vibrator 4. It is set to a value such that

I1 = V × C / t (1)
After such preprocessing, the transmission circuit 1 uses the positive electrode drive circuit 2a and the negative electrode drive circuit 2b at times t3 to t4 to provide a pulse signal (ideally) having a pulse width as narrow as possible at the drive input terminal 7. The pulse application process of applying the impulse signal) is executed. Specifically, the transmission circuit 1 controls the switch 13a to be off and the switch 13b to be on at time t3. As a result, the voltage applied to the ultrasonic transducer 4 sharply drops from the positive electrode power supply H VDD to the negative electrode power supply HVSS with the pulse current value I2. When the voltage is lowered to the negative electrode power supply HVSS, the transmission circuit 1 controls the switch 13b to be turned off and the switch 13a to be turned on at the time t4, contrary to the time t3. As a result, the voltage applied to the ultrasonic transducer 4 sharply rises from the negative electrode power supply HVSS to the positive electrode power supply H VDD with the pulse current value I2. As a result, an impulse signal is ideally generated.

After such pulse application processing, the transmission circuit 1 uses the reference drive circuit 3 at time t5 to t6 to set the voltage of the drive input terminal 7 to the band of the ultrasonic transducer 4 based on the variable current source 11b. Post processing is performed to drive toward the reference power supply GND with a second gradient that is an outside frequency. Specifically, the transmission circuit 1 sets the variable current sources 10a, 10b, 11a, and 11b to the inclination setting current value I1 again at time t5, and controls the switch 14b to be turned on. As a result, the voltage applied to the ultrasonic vibrator 4 gradually drops to the reference power supply GND with a second inclination. Then, after the voltage reaches the reference power supply GND, the transmission circuit 1 controls the switch 14b to be turned off at time t6.

By such control, the transmission circuit 1 can generate a high voltage single wave transmission signal that becomes an'L'pulse signal (substantially an'L' pulse signal).

FIG. 3 is a waveform diagram showing another example of the high-voltage single-wave transmission signal generation operation in the transmission circuit of FIG. In FIG. 2, the waveform is defined to have a symmetrical shape by using the same inclination setting current value I1 in the pre-processing (time t1 to t2) and the post processing (time t5 to t6). However, the shape does not necessarily have to be symmetrical. For example, as shown in FIG. 3, in the post processing (time t5 to t6), the current value I3 is larger than the tilt setting current value I1 and smaller than the pulse current value I2. It is also possible to define an asymmetrical shape by using.

The current value I3 is a value set so that the inclination becomes a frequency outside the band of the ultrasonic vibrator 4, as in the case of the inclination setting current value I1. For example, if it is desired to receive the ultrasonic vibrator 4 immediately after the post processing, the current value I3 can be set to a value somewhat large.

FIG. 4 is a waveform diagram showing still another example of the generation operation of the high voltage single wave transmission signal in the transmission circuit of FIG. In FIG. 4, the controls of the switch 13a and the switch 13b in FIG. 2 are exchanged, and the switch 14a is controlled to be turned on instead of the switch 14b in the post processing, so that a high voltage single wave transmission signal which becomes an'H'pulse is generated. Will be generated. That is, in the pre-processing (time t1 to t2), the transmission circuit 1 uses the negative electrode drive circuit 2b to shift the voltage of the drive input terminal 7 from the reference power supply GND to the negative electrode power supply HVSS with the first inclination. .. Further, in the post processing (time t5 to t6), the transmission circuit 1 directs the voltage of the drive input terminal 7 toward the reference power supply GND with a second inclination based on the variable current source 11a by using the reference drive circuit 3. To drive.

Here, the transmission circuit 1 generates a high-voltage single-wave transmission signal of the'L'pulse signal and the'H' pulse signal as shown in FIGS. 2 and 4, for example, to perform a diagnosis using a distortion component. Things can be done. Specifically, the reflected waveform obtained from the living body and the incident waveform associated with the high-voltage single-wave transmission signal of FIG. 4 according to the incident waveform from the ultrasonic transducer 4 accompanying the high-voltage single-wave transmission signal of FIG. By adding the reflection waveform according to the above, only the distortion component of the reflection waveform generated in the living body can be extracted for diagnosis.

FIG. 5 is a waveform diagram showing an example of a rectangular wave signal generation operation in the transmission circuit of FIG. In FIG. 5, the transmission circuit 1 controls each switch in a state where the variable current sources 10a, 10b, 11a, and 11b are set to constant values (here, the pulse current value I2). Here, the transmission circuit 1 alternately controls the switches 13a and 13b to be turned on at each time t1, t2, and t3, and at the time t4, controls the switch 13a in the on state to be turned off and turns the switch 14b on. Control. As a result, not only a high voltage single wave transmission signal but also a general rectangular wave signal can be generated.

As a diagnostic method using an ultrasonic diagnostic apparatus, for example, in addition to a method of performing diagnosis using a high-voltage single-wave transmission signal as shown in FIGS. 2 and 4, several waves of a square wave signal as shown in FIG. 5 are transmitted. A method for performing diagnosis (for example, a Pulsed Wave method) is known. The transmission circuit 1 of FIG. 1 can generate such a rectangular wave signal with simple control in addition to the high voltage single wave transmission signal.

<< Detailed configuration of transmission circuit >>
FIG. 6 is a circuit diagram showing a detailed configuration example of the transmission circuit of FIG. In the transmission circuit 1 of FIG. 6, the positive drive circuit 2a of FIG. 1 corresponds to the current mirror circuit 61a of FIG. 6, the level shifter 62a, the n-channel MOS transistor (hereinafter referred to as nMOS transistor) MN3, and the switch 63a. .. The negative electrode drive circuit 2b of FIG. 1 corresponds to the current mirror circuit 61b of FIG. 6, the level shifter 62b, the p-channel MOS transistor (hereinafter referred to as pMOS transistor) MP3, and the switch 63b. The reference drive circuit 3 of FIG. 1 corresponds to the pMOS transistor MP5, the nMOS transistor MN5, and the switches 63c, 63d of FIG.

The current mirror circuit 61a constitutes a main part of the variable current source 10a of FIG. 1, a pMOS transistor MP1 in which a current path is formed between the positive power supply H VDD and the drive input terminal 7, a pMOS transistor MP1 and a current mirror circuit. It is provided with a pMOS transistor MP2. The nMOS transistor MN3 is coupled in series with the pMOS transistor MP2 via a level shifter 62a.

The level shifter 62a is composed of the nMOS transistor MN4, and the drain of the nMOS transistor MN3 is set to be substantially equal to or lower than the voltage level of the internal power supply VDD by applying the internal power supply VDD to the gate. As a result, a voltage higher than the internal power supply VDD is not applied to the nMOS transistor MN3, so that a low-voltage nMOS transistor can be used and the mounting area can be reduced. The source of the nMOS transistor MN3 is coupled to the internal reference power supply VSS. The switch 63a corresponds to the switch 13a of FIG. 1, and when it is turned on by the control signal Sa, it drives between the gate and the source of the nMOS transistor MN3 with the variable voltage VRa generated by the current value setting circuit 100.

The current mirror circuit 61b constitutes a main part of the variable current source 10b of FIG. 1, an nMOS transistor MN1 in which a current path is formed between the negative power supply HVSS and the drive input terminal 7, an nMOS transistor MN1 and a current mirror circuit. The nMOS transistor MN2 is provided. The pMOS transistor MP3 is coupled in series with the nMOS transistor MN2 via a level shifter 62b.

The level shifter 62b is composed of the pMOS transistor MP4, and by applying the internal reference power supply VSS to the gate, the drain of the pMOS transistor MP3 is set to be substantially equal to or higher than the voltage level of the internal reference power supply VSS. The source of the pMOS transistor MP3 is coupled to the internal power supply VDD. The switch 63b corresponds to the switch 13b of FIG. 1, and when it is controlled to be turned on by the control signal Sb, the switch 63b drives between the gate and the source of the pMOS transistor MP3 with the variable voltage VRb generated by the current value setting circuit 100.

The pMOS transistor MP5 has a current path formed between the reference power supply GND and the drive input terminal 7, and serves as the main part of the variable current source 11a of FIG. The switch 63c corresponds to the switch 14a of FIG. 1, and when it is controlled to be turned on by the control signal Sc, the switch 63c drives between the gate and the source of the pMOS transistor MP5 with the variable voltage VRc generated by the current value setting circuit 100. The nMOS transistor MN5 has a current path formed between the reference power supply GND and the drive input terminal 7, and serves as the main part of the variable current source 11b of FIG. The switch 63d corresponds to the switch 14b in FIG. 1 and drives between the gate and the source of the nMOS transistor MN5 with the variable voltage VRd generated by the current value setting circuit 100 when it is controlled to be turned on by the control signal Sd.

FIG. 7 is a circuit diagram showing a detailed configuration example of the current value setting circuit in FIG. The current value setting circuit 100 shown in FIG. 7 includes a positive side current value setting circuit 100a and a negative side current value setting circuit 100b. The positive side current value setting circuit 100a includes n pMOS transistors MP [1] to MP [n] and a current / voltage conversion circuit 101a. A predetermined reference current IR is supplied to the pMOS transistor MP [1].

The pMOS transistors MP [2] to MP [n] have, for example, a size ratio of 2 ⁿ , and form a current mirror circuit with the pMOS transistor MP [1]. At this time, one or a plurality of transistors constituting the current mirror circuit are selected from the pMOS transistors MP [2] to MP [n] by the current value setting signal ISET. The current / voltage conversion circuit 101a is composed of a diode-connected nMOS transistor MN10, and converts the total current In flowing through the pMOS transistors MP [2] to MP [n] into a gate-source voltage to convert the variable voltages VRa and VRd. To generate.

Similarly, the negative side current value setting circuit 100b includes n nMOS transistors MN [1] to MN [n] and a current / voltage conversion circuit 101b. A predetermined reference current IR is supplied to the nMOS transistor MN [1], and the nMOS transistors MN [2] to MN [n] form a current mirror circuit together with the nMOS transistor MN [1]. At this time, the transistors constituting the current mirror circuit are selected by the current value setting signal ISET. The current / voltage conversion circuit 101b is composed of a diode-connected pMOS transistor MP10, and converts the total current Ip flowing through the nMOS transistors MN [2] to MN [n] into a gate-source voltage to convert the variable voltages VRb and VRc. To generate.

In this way, the positive side current value setting circuit 100a variably controls the current flowing through the pMOS transistor MP1 and the current flowing through the nMOS transistor MN5 in FIG. 6 by generating variable voltages VRa and VRd according to the setting. Similarly, the negative side current value setting circuit 100b variably controls the current flowing through the nMOS transistor MN1 and the current flowing through the pMOS transistor MP5 in FIG. 6 by generating variable voltages VRb and VRc according to the setting.

Here, the variable voltages VRa and VRd are generated by the same positive side current value setting circuit 100a, and the variable voltages VRb and VRc are generated by the same negative side current value setting circuit 100b, but the current values are set independently of each other. A circuit may be provided. Strictly speaking, the variable voltages VRa, VRb, VRc, and VRd are appropriately level-shifted and then applied to the corresponding transistors (MN3, MP3, MP5, MN5) in FIG. For example, since the variable voltage VRc in FIG. 7 is generated as a gate-source voltage based on the internal power supply voltage VDD, the level is shifted so as to be a gate-source voltage based on the reference power supply GND. It is applied to the pMOS transistor MP5.

<< Outline configuration of ultrasonic diagnostic equipment >>
FIG. 8 is a schematic view showing a configuration example of the ultrasonic diagnostic apparatus according to the first embodiment of the present invention. The ultrasonic diagnostic apparatus of FIG. 8 includes an ultrasonic probe 12 equipped with an ultrasonic transducer 4 and an ultrasonic diagnostic apparatus main body 6 which is coupled to the ultrasonic probe 12 via a cable 8 to control the ultrasonic probe 12. Has. The ultrasonic diagnostic apparatus main body 6 has, for example, a CPU (Central Processor Unit) that controls the entire apparatus, a storage device, and a communication IF (IF: InterFace) apparatus for communicating with an external device inside the housing. .. The storage device is an HDD (Hard Disk Drive) that stores a program or the like executed by the CPU, a RAM that temporarily stores data to be processed, or the like.

Further, the ultrasonic diagnostic apparatus main body 6 has, for example, various power supply circuits and an image processing circuit for image processing signals from the ultrasonic probe 12 inside the housing. Further, the ultrasonic diagnostic apparatus main body 6 has, for example, an input device such as a keyboard and a mouse, and an output device such as a liquid crystal display device. The input device may be, for example, a touch panel provided on the liquid crystal display device. The ultrasonic diagnostic apparatus main body 6 has a structure that can be freely moved on the floor surface by a caster or the like attached to the bottom surface.

In such a configuration, in the example of FIG. 8, the transmission circuit 1 of FIG. 1 is mounted on the ultrasonic diagnostic apparatus main body 6. The transmission signal from the transmission circuit 1 is transmitted to the ultrasonic probe 12 via the cable 8.

<< Main effect of Embodiment 1 >>
As described above, by using the method of the first embodiment, it is possible to typically generate the high voltage single wave transmission signals of FIGS. 2 and 4 with simple control. Specifically, unlike the methods of Patent Documents 1 to 3, a method that does not use a DAC eliminates the need for complicated control at a high frequency. For example, when DAC is used in the period of preprocessing (time t1 to t2) of FIG. 2, it is necessary to generate a digital signal with high frequency in each sampling cycle in order to realize the first inclination. On the other hand, when the configuration of FIG. 1 is used, it is sufficient to set the inclination setting current value I1 and control the switch 13a to be on for a required period. Further, by using the transmission circuit 1 of FIG. 1, it is not necessary to generate a digital signal with high frequency, so that power consumption may be reduced.

(Embodiment 2)
<< Outline configuration and operation of transmission circuit >>
FIG. 9 is a circuit diagram showing a schematic configuration example of a main part in the transmission circuit of the ultrasonic oscillator according to the second embodiment of the present invention. FIG. 10 is a waveform diagram showing an example of a high voltage single wave transmission signal generation operation in the transmission circuit of FIG. The transmission circuit 1 shown in FIG. 9 has a configuration in which a resistance element 5 is added to the reference drive circuit 3 as compared with the configuration example of FIG. The resistance element 5 is provided between the reference power supply GND and the drive input terminal 7, and has a resistance value based on the above-mentioned first inclination.

The operation shown in FIG. 10 is different from the operation shown in FIG. 2 in the post processing (time t5 to t6) operation. The post-processing of FIG. 2 was performed by controlling the switch 14b to be turned on with each variable current source (at least 11b) set to the tilt setting current value I1, but the post-processing of FIG. 10 is particularly active. No control is performed. In this case, the voltage of the drive input terminal 7 automatically returns to the reference power supply GND with a slope (time constant) determined by the resistance value of the resistance element 5 and the capacitance of the ultrasonic vibrator 4.

Here, for example, when generating the high-voltage single-wave transmission signal of FIGS. 2 or 4, the variable current sources 11a and 11b and the switches 14a and 14b in the reference drive circuit 3 are not particularly required. Therefore, by deleting these circuits, the circuit scale can be reduced and the control can be further simplified. However, since these circuits are required when generating the rectangular wave signal as shown in FIG. 5, in the example of FIG. 9, they remain in the reference drive circuit 3.

(Embodiment 3)
<< Outline configuration of ultrasonic diagnostic equipment >>
FIG. 11 is a schematic view showing a configuration example of the ultrasonic diagnostic apparatus according to the third embodiment of the present invention. The ultrasonic diagnostic apparatus shown in FIG. 11 has a configuration in which a transmission circuit is mounted in the ultrasonic probe 12, unlike the configuration example of FIG. In the example of FIG. 11, the ultrasonic probe 12 has a 2D (Dimension) array oscillator 12a and a 2D array IC (Integrated Circuit) 12b. The 2D array oscillator 12a has a plurality of ultrasonic oscillators that emit ultrasonic waves at the contact surface of the ultrasonic probe 12 with the human body. The plurality of ultrasonic vibrators are arranged in a two-dimensional shape (planar shape). The transmission circuit is mounted on the 2D array IC12b.

The 2D array IC 12b is arranged so as to face the 2D array oscillator 12a, and has a plurality of control circuit units provided corresponding to the plurality of ultrasonic oscillators. For example, one control circuit unit in the 2D array IC 12b is electrically coupled to one ultrasonic oscillator in the 2D array oscillator 12a. The plurality of control circuit units are also arranged two-dimensionally in the 2D array IC12b.

For example, in order to acquire a three-dimensional diagnostic image, there is known a method of arranging a plurality of ultrasonic vibrators in a two-dimensional manner in this way. In this case, since a large number of ultrasonic oscillators are provided in the ultrasonic probe 12, if the transmission circuit 1 is mounted on the ultrasonic diagnostic apparatus main body 6 as shown in FIG. 8, the number of wirings in the cable 8 increases. Can be a problem. Therefore, it is beneficial to reduce the number of wirings in the cable 8 as much as possible by mounting the transmission circuit 1 in the ultrasonic probe 12. However, if the transmission circuit 1 is mounted in the ultrasonic probe 12, the heat generation of the ultrasonic probe 12 increases, so that it is required to reduce the power consumption of the transmission circuit 1.

<< Schematic configuration of 2D array IC >>
FIG. 12 is a schematic view showing a configuration example of the 2D array IC in FIG. As shown in FIG. 12, the 2D array IC 12b of FIG. 11 includes a plurality of control circuit units 40 arranged in a two-dimensional manner (N rows and M columns), and the plurality of control circuit units 40 are also two-dimensional. It is configured to control each of a plurality of ultrasonic vibrators 4 arranged in a shape. Further, in the 2D array IC 12b, peripheral circuits 41 and 42 are arranged around the plurality of control circuit units 40.

Each of the plurality of control circuit units 40 has a transmission circuit 1 shown in the first and second embodiments, a reception circuit 47, and a control circuit 46 including a variable delay circuit 48. The receiving circuit 47 receives the reflected waveform from the living body via the ultrasonic vibrator 4 and outputs the received signal to the control circuit 46. The control circuit 46 appropriately controls the delay time of the transmission / reception signal of the ultrasonic vibrator 4 by using the variable delay circuit 48. That is, the control circuit 46 changes the phase of the transmitted / received signal to improve the signal quality (image) by increasing / decreasing the delay time of the signal given to the ultrasonic transducer 4 (given in the case of reception).

At this time, the variable delay circuit 48 has its own delay time based on the delay time 43 in row units and the delay time 44 in column units calculated by the logic circuits in the peripheral circuits 41 and 42, for example, depending on the addition result or the like. To determine. As a result, the variable delay circuits 48 in the plurality of control circuit units 40 set different delay times to themselves, at least in part. Further, the current value setting circuit 100 of FIG. 7 is provided in the vicinity of the peripheral circuits 41 and 42. The current value setting circuit 100 is not provided for each of the plurality of control circuit units 40, but is provided in common for the plurality of control circuit units 40, and the generated variable voltages VRa, VRb, VRc, and VRd are provided in the plurality of control circuits. It is commonly supplied to the transmission circuit 1 of the unit 40.

FIG. 13 is a schematic view showing a partial configuration example of the control circuit in FIG. The control circuit 46 of FIG. 13 includes a variable delay circuit 48 and various logical operation circuits (here, or operation circuits 51 and 52, inverter circuits 53, and operation circuits 54 to 57). A positive side control signal PC, a negative side control signal NC, a pre-signal ZC, a post signal YC, and a positive / negative selection signal XC, which are common signals of a plurality of control units 40, are input to the control circuit 46. These signals are generated by, for example, the ultrasonic diagnostic apparatus main body 6 and input via the cable 8. In response to these signals, the control circuit 46 receives the control signals of the switches 13a and 13b of FIG. 1 (that is, the control signals Sa and Sb of the switches 63a and 63b of FIG. 6) and the control signals of the switches 14a and 14b of FIG. (That is, the control signals Sc and Sd of the switches 63c and 63d in FIG. 6) are output.

The positive side control signal PC is a signal that determines the on period of the switch 13a of FIG. 1, and the negative side control signal NC is a signal that determines the on period of the switch 13b of FIG. The pre-signal ZC and the post-signal YC are signals that determine the execution period of the pre-processing and post-processing described above, respectively. The positive / negative selection signal XC is a signal that selects the high-voltage single-wave transmission signal (that is, the'L'pulse signal or the'H' pulse signal) of FIG. 2 or 4 as a transmission signal. The variable delay circuit 48 delays both the positive control signal PC and the negative control signal NC, and outputs the delayed positive control signal PCd and the negative control signal NCd.

<< Schematic operation of 2D array IC >>
FIG. 14 is a waveform diagram showing a schematic operation example of the 2D array IC of FIG. In FIG. 14, channel A corresponds to a certain control unit 40, and channel B corresponds to a control unit 40 having a delay time different from that of the control unit. First, the control circuits 46 of the channel A and the channel B both cause their own transmission circuit 1 to execute the above-mentioned pre-processing according to the input common pre-signal ZC.

In this example, in the control circuit 46 of FIG. 13, the positive / negative selection signal is set to the'L'level corresponding to the'L' pulse signal, and the pre-signal ZC is controlled via the and arithmetic circuit 54 and the or arithmetic circuit 51. It is output as a signal Sa. As a result, both the transmission circuit 1 of the channel A and the transmission circuit 1 of the channel B gently direct the voltage of the drive input terminal 7 toward the positive electrode power supply H VDD in the'H'level period of the pre-signal ZC by using the tilt setting current value I1. Raise to. After that, the common current value setting circuit 100 shown in FIGS. 7 and 12 tilts and sets the current value of the drive current at the stage where the pre-signal ZC transitions to the'L'level (that is, the stage where the pre-processing is completed). The current value I1 for pulse is changed to the current value I2 for pulse.

On the other hand, in order to generate an'L'pulse signal in the control circuit 46 following the pre-signal ZC, a positive side control signal PC, a negative side control signal NC, and a positive side control signal PC, which are'H' pulse signals, respectively. Are input in sequence. The control circuit 46 of the channel B adds a predetermined delay to the input control signal, and sequentially outputs the positive side control signal PCd, the negative side control signal NCd, and the positive side control signal PCd after the delay. On the other hand, the control circuit 46 of the channel A adds a delay larger than that of the channel B, for example, to the input control signal, and adds the delayed positive control signal PCd, negative control signal NCd, and positive control signal PCd. Output sequentially.

The control circuit 46 of the channel A and the channel B causes its own transmission circuit 1 to execute the pulse application process described above by using the positive side control signal PCd and the negative side control signal NCd after the delay. In this example, in the control circuit 46 of FIG. 13, the positive side control signal PCd after the delay is output as the control signal Sa via the or arithmetic circuit 51, and the negative control signal NCd after the delay is output via the or arithmetic circuit 52. Is output as a control signal Sb. As a result, the transmission circuits 1 of channel A and channel B are driven and input using the pulse current value I2 at different timings according to the input delay-side positive control signal PCd and negative control signal NCd. An'L' pulse signal is applied to the terminal 7.

When the pulse application processing of channel A and channel B is completed, the control circuits 46 of channel A and channel B both cause their own transmission circuit 1 to perform the above-mentioned post processing in response to the input post signal YC. In this example, in the control circuit 46 of FIG. 13, the post signal YC is output as a control signal Sd via the AND operation circuit 56. Further, the common current value setting circuit 100 sets the current value of the drive current from the pulse current value I2 at the stage where the post signal YC transitions to the'H'level (that is, the stage where the pulse application processing of all channels is completed). Change to the tilt setting current value I1. As a result, both the transmission circuit 1 of the channel A and the transmission circuit 1 of the channel B gently direct the voltage of the drive input terminal 7 toward the reference power supply GND by using the tilt setting current value I1 during the'H'level period of the post signal YC. To descend to.

Although the description has been given here with an example of two channels, the same applies to three or more channels. In this case, for example, the channel having the maximum delay time is preprocessed, and then the positive electrode power supply H VDD of the drive input terminal 7 is held by the capacitance of the ultrasonic transducer 4 for a predetermined period, and the pulse application process is performed from that state. Just do it. Further, here, an example of generating a high-voltage single-wave transmission signal that becomes an'L'pulse signal has been described, but by setting the positive / negative selection signal XC to the'H'level, it becomes an'H' pulse signal. The high voltage single wave transmission signal is also generated in the same manner.

<< Main effect of Embodiment 3 >>
As described above, by using the method of the third embodiment, typically, in addition to the effects described in the first embodiment and the like, when the diagnosis is performed while appropriately delaying the transmission / reception signals of the plurality of ultrasonic vibrators 4. Even so, it becomes possible to generate the high-voltage single-wave transmission signal of FIGS. 2 and 4 with simple control. Specifically, for example, in the methods of Patent Documents 1 to 3, since one DAC can basically control only one ultrasonic oscillator 4, for example, a plurality of ultrasonic probes 12 are contained. It is necessary to provide the same number of DACs as the ultrasonic oscillator 4 of the above. As a result, there is a risk that the circuit scale will increase, the power consumption will increase accordingly, and in some cases, the wiring in the cable 8 will become complicated.

On the other hand, in the method of the third embodiment, unlike the DAC method, the setting of the current value of the drive current and the setting of the application period of the drive current can be performed independently. Therefore, as shown in FIG. 14 and the like, after standardizing the setting of the drive current by the current value setting circuit 100, the pre-processing and the post-processing are standardized for each channel, and only the pulse application processing is performed for each channel. It becomes possible to do things independently. This eliminates the need to control the current value independently for each channel as in the case of the DAC method, and simplifies the control.

Further, since the current value setting circuit 100 can be shared, the circuit scale can be reduced, and the power consumption can be reduced accordingly. As a result, the heat generation of the ultrasonic probe 12 can be suppressed. Further, the signal input from the cable 8 may be a signal as shown in FIGS. 13 and 14. Therefore, the number of signals input from the cable 8 can be reduced as compared with the case where each channel is individually controlled by the signal from the cable 8, for example, and the complexity of the wiring in the cable 8 is also a particular problem. It doesn't become.

Although the invention made by the present inventor has been specifically described above based on the embodiment, the present invention is not limited to the above embodiment and can be variously modified without departing from the gist thereof. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. .. Further, it is possible to add / delete / replace other configurations with respect to a part of the configurations of each embodiment.

1 Transmission circuit 2a Positive drive circuit 2b Negative drive circuit 3 Reference drive circuit 4 Ultrasonic transducer 5 Resistance element 6 Ultrasonic diagnostic device main unit 7 Drive input terminal 8 Cable 10a, 10b, 11a, 11b Variable current source 12 Super Sonic probe 13a, 13b, 14a, 14b, 63a to 63d Switch 40 Control circuit unit 46 Control circuit 48 Variable delay circuit 61a, 61b Current mirror circuit 100 Current value setting circuit 100a Positive side current value setting circuit 100b Negative side current value setting circuit GND Reference power supply H VDD Positive power supply HVSS Negative power supply MN nMOS transistor MP pMOS transistor NC Negative side control signal PC Positive side control signal Sa to Sd Control signal VRa to VRd Variable voltage ZC pre-signal

Claims (12)

The drive input terminal of the ultrasonic transducer is directed to the positive electrode power supply by the drive current based on the first variable current source, including the first variable current source and the first switch, and during the on period of the first switch. Drive circuit for positive electrode to drive and
For the negative electrode, which includes a second variable current source and a second switch, and drives the drive input terminal toward the negative electrode power supply by a drive current based on the second variable current source during the on period of the second switch. Drive circuit and
A reference drive circuit that drives the drive input terminal toward a reference power source that serves as a reference for the positive electrode power supply and the negative electrode power supply.
A transmission circuit of the ultrasonic transducers that have a,
The transmission circuit
Using either the positive electrode drive circuit or the negative electrode drive circuit, the voltage of the drive input terminal is directed from the reference power source to the positive electrode power source or the negative electrode power source to be a frequency outside the band of the ultrasonic transducer. Pre-processing to transition with the first inclination and
After the pre-processing, a pulse application process of applying a pulse signal having a predetermined pulse width to the drive input terminal by using the positive electrode drive circuit and the negative electrode drive circuit, and
To execute,
Transmission circuit of ultrasonic oscillator. In the transmission circuit of the ultrasonic oscillator according to claim 1,
The reference drive circuit drives the drive input terminal toward the reference power supply with a second inclination that is a frequency outside the band of the ultrasonic oscillator.
Transmission circuit of ultrasonic oscillator. In the transmission circuit of the ultrasonic oscillator according to claim 2,
The reference drive circuit includes a third variable current source and a third switch, and the drive input terminal is driven by a drive current based on the third variable current source during the on period of the third switch. Drive towards power and
After the pulse application process, the transmission circuit uses the reference drive circuit to direct the voltage of the drive input terminal toward the reference power supply with the second inclination based on the third variable current source. Perform driving post processing,
Transmission circuit of ultrasonic oscillator. In the transmission circuit of the ultrasonic oscillator according to claim 2,
The reference drive circuit includes a resistance element provided between the reference power supply and the drive input terminal and having a resistance value based on the second inclination.
Transmission circuit of ultrasonic oscillator. In the transmission circuit of the ultrasonic oscillator according to claim 1,
The drive circuit for the positive electrode is
A first conductive type first A transistor forming a current path between the positive electrode power supply and the drive input terminal,
The first A transistor, the first conductive type second A transistor constituting the current mirror circuit, and the second A transistor.
A second conductive type third A transistor coupled in series with the second A transistor,
A first current value setting circuit that generates a variable voltage according to the setting, and
The first switch that drives the third A transistor with the variable voltage generated by the first current value setting circuit when controlled to be turned on.
Have,
The drive circuit for the negative electrode is
The second conductive type first B transistor forming a current path between the negative electrode power supply and the drive input terminal,
The first B transistor, the second conductive type second B transistor constituting the current mirror circuit, and the second B transistor.
The first conductive type third B transistor coupled in series with the second B transistor,
A second current value setting circuit that generates a variable voltage according to the setting, and
The second switch that drives the third B transistor with the variable voltage generated by the second current value setting circuit when controlled to be turned on.
Have,
Transmission circuit of ultrasonic oscillator. It is an ultrasonic probe that has a plurality of ultrasonic transducers and a plurality of control circuit units provided corresponding to the plurality of ultrasonic transducers, and is coupled to the ultrasonic diagnostic apparatus main body via a cable. hand,
Each of the plurality of control circuit units includes a transmission circuit.
The transmission circuit
The drive input terminal of the ultrasonic transducer is directed to the positive electrode power supply by the drive current based on the first variable current source, including the first variable current source and the first switch, and during the on period of the first switch. Drive circuit for positive electrode and
For the negative electrode, which includes a second variable current source and a second switch, and drives the drive input terminal toward the negative electrode power supply by a drive current based on the second variable current source during the on period of the second switch. Drive circuit and
A reference drive circuit that drives the drive input terminal toward a reference power source that serves as a reference for the positive electrode power supply and the negative electrode power supply.
Have,
The transmission circuit
Using either the positive electrode drive circuit or the negative electrode drive circuit, the voltage of the drive input terminal is directed from the reference power source to the positive electrode power source or the negative electrode power source to be a frequency outside the band of the ultrasonic transducer. Pre-processing to transition with the first inclination and
After the pre-processing, a pulse application process of applying a pulse signal having a predetermined pulse width to the drive input terminal by using the positive electrode drive circuit and the negative electrode drive circuit, and
To execute,
Ultrasonic probe. In the ultrasonic probe according to claim 6,
Each of the plurality of control circuit units includes a control circuit including a variable delay circuit.
At least a part of the plurality of variable delay circuits is preset with different delay times.
Each of the plurality of control circuits
In response to the input common pre-signal, the first process of causing the transmission circuit of its own to execute the pre-process, and
The first control according to the input common first control signal that determines the on period of the first switch and the common second control signal that determines the on period of the second switch. After delaying the signal and the second control signal by its own variable delay circuit, the pulse is applied to its own transmission circuit by using the first control signal and the second control signal after the delay. The second process to execute the process and
To execute,
Ultrasonic probe. In the ultrasonic probe according to claim 7,
The drive circuit for the positive electrode is
A first conductive type first A transistor forming a current path between the positive electrode power supply and the drive input terminal,
A first current value setting circuit that variably controls the current flowing through the first A transistor, and
Have,
The drive circuit for the negative electrode is
A second conductive type first B transistor that forms a current path between the negative electrode power supply and the drive input terminal,
A second current value setting circuit that variably controls the current flowing through the first B transistor, and
Have,
The first current value setting circuit and the second current value setting circuit are commonly provided in the plurality of control circuit units, and when the pre-processing is completed, the current value is changed from the pre-processing to the pulse. Change to application processing,
Ultrasonic probe. In the ultrasonic probe according to claim 6,
The reference drive circuit drives the drive input terminal toward the reference power source with a second inclination that is a frequency outside the band of the ultrasonic oscillator.
Ultrasonic probe. In the ultrasonic probe according to claim 9,
The reference drive circuit includes a third variable current source and a third switch, and the drive input terminal is driven by a drive current based on the third variable current source during the on period of the third switch. Drive towards power and
After the pulse application process, the transmission circuit uses the reference drive circuit to direct the voltage of the drive input terminal toward the reference power supply with the second inclination based on the third variable current source. Perform driving post processing,
Ultrasonic probe. An ultrasonic diagnostic apparatus having a plurality of ultrasonic vibrators and a plurality of control circuit units provided corresponding to the plurality of ultrasonic vibrators.
Each of the plurality of control circuit units includes a transmission circuit.
The transmission circuit
The drive input terminal of the ultrasonic transducer is directed to the positive electrode power supply by the drive current based on the first variable current source, including the first variable current source and the first switch, and during the on period of the first switch. Drive circuit for positive electrode and
For the negative electrode, which includes a second variable current source and a second switch, and drives the drive input terminal toward the negative electrode power supply by a drive current based on the second variable current source during the on period of the second switch. Drive circuit and
A reference drive circuit that drives the drive input terminal toward a reference power source that serves as a reference for the positive electrode power supply and the negative electrode power supply.
Have,
The transmission circuit
Using either the positive electrode drive circuit or the negative electrode drive circuit, the voltage of the drive input terminal is directed from the reference power source to the positive electrode power source or the negative electrode power source to be a frequency outside the band of the ultrasonic transducer. Pre-processing to transition with the first inclination and
After the pre-processing, a pulse application process of applying a pulse signal having a predetermined pulse width to the drive input terminal by using the positive electrode drive circuit and the negative electrode drive circuit, and
To execute,
Ultrasonic diagnostic equipment. In the ultrasonic diagnostic apparatus according to claim 11,
The ultrasonic diagnostic apparatus is
An ultrasonic probe equipped with the plurality of ultrasonic transducers and
An ultrasonic diagnostic apparatus main body that is connected to the ultrasonic probe via a cable and controls the ultrasonic probe.
Have,
The plurality of control circuit units are mounted on the ultrasonic probe.
Ultrasonic diagnostic equipment.

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