JP2006015071A - Ultrasonic diagnostic equipment - Google Patents

Abstract

A change in output voltage of a transmission power supply between modes is suppressed, and power consumption and heat generation in a capacitor for compensating for a voltage drop are reduced.
A transmission pulse generator 15 comprising a transformer 16 and a switching means for driving a transducer for transmitting and receiving ultrasonic waves, a transmission power supply 5 for supplying current to the transmission pulse generator, and a transmission A capacitor connected to the output terminal of the power supply and a controller 4 for controlling the voltage of the transmission power supply are provided. The primary winding of the transformer is composed of a plurality of primary windings 16a and 16b having different numbers of windings, and each of the plurality of primary windings includes two switching means 13A, 13B and 17A. , 17B are connected to each other, and currents in opposite directions are supplied from the transmission power source to the primary windings via the two switch means.
[Selection] Figure 1

Description

  The present invention relates to an ultrasonic diagnostic apparatus for obtaining information in a body by transmitting and receiving ultrasonic waves using a vibrator, and more particularly to improvement of a circuit for driving the vibrator.

  The principle of an ultrasonic diagnostic apparatus that obtains two-dimensional information in the body by repeatedly transmitting and receiving ultrasonic waves in the body using a vibrator is widely known. As a two-dimensional scanning method, a single transducer is mechanically scanned and an array transducer is used. The direction of transmission / reception from the array transducer is changed, or the array transducer used for transmission / reception is slightly selected. There is known a method of performing scanning by changing each time. Hereinafter, a method called two-dimensional scanning by changing the deflection angle in the transmission / reception direction from the array transducer, which is called sector scanning, will be described.

  An ultrasonic diagnostic apparatus that performs sector scanning using an array transducer is configured as shown in FIG. 6, for example. Transmission pulse generators 2-1 to 2-8 are connected to transducers 1-1 to 1-8 that transmit and receive ultrasonic waves, and are generated by transmission trigger generator 3 under the control of controller 4. Based on the generated trigger pulse, drive pulses are generated from the transmission pulse generators 2-1 to 2-8, and the vibrators 1-1 to 1-8 are driven. The amplitude of the drive pulse generated by the transmission pulse generators 2-1 to 2-8 is determined by the output voltage of the transmission power source 5 controlled by the controller 4. A capacitor 11 is installed at the output terminal of the transmission power supply 5 for voltage stabilization. Also, receiving amplifiers 6-1 to 6-8 are connected to the transducers 1-1 to 1-8, and after being amplified to an appropriate gain, the beamformer 7 performs delay addition. Further, the signal detected by the detector 8 is scan-converted by a scan converter (DSC) 9 and displayed on the display 10.

  An example of the transmission pulse generator 2 will be described with reference to FIG. As shown in FIG. 7A, the inside of the transmission pulse generator 2 includes a step-up transformer 12 and switch means 13A and 13B. The primary side of the transformer 12 has an intermediate tap, and current is supplied from the transmission power supply 5 to the intermediate tap.

  When no transmission pulse is generated, the switch means 13A and 13B are OFF. When generating a transmission pulse, the switch means 13A is first turned ON. As a result, a current flows upward from the intermediate tap through the primary side winding of the transformer, a magnetic flux is generated, a current due to the induced electromotive force is generated on the secondary side, and the vibrator 1 is driven. Next, when the switch means 13A is turned OFF and the switch means 13B is turned ON, a current flows downward from the intermediate tap through the primary winding of the transformer, a magnetic flux is generated, and a current due to the induced electromotive force is generated on the secondary side. However, the direction of this current is opposite to that when the switch means 13A is turned on. In this way, a bipolar transmission pulse is generated on the secondary side of the transformer and drives the vibrator.

  In recent ultrasonic diagnostic apparatuses, in addition to the B mode display in which amplitude information is replaced with luminance, a Doppler mode in which blood flow information is displayed in a spectrum, a color flow mode in which blood flow information is displayed in color, and the like are 1 It is possible to operate with one device, and it is possible to perform different mode operations for each scanning line.

  In the color flow mode or the Doppler mode, sensitivity is more important than the B mode in which resolution is important. Therefore, the transmission waveform is often displayed with a relatively small wave number in the B mode and with a relatively large wave number in the color flow mode or the Doppler mode.

  On the other hand, the intensity of ultrasonic waves that can enter the body is regulated, and the power per unit time increases when the number of waves is large even with the same amplitude, so it is necessary to set the amplitude small. Further, in the B mode with a small wave number, in order to improve the S / N ratio, it is necessary to increase the amplitude within the range allowed by the regulation.

  As shown in FIG. 7B, the output voltage VB of the transmission power source 5 becomes a voltage of VB1 when a large amplitude in the B mode is required by the control of the controller 4, and the transmission pulse of the amplitude V1 is changed. appear. In the color flow mode or the Doppler mode, the output voltage VB of the transmission power supply 5 drops to VB2, and a transmission pulse having an amplitude V2 is generated.

  In order to switch between the B mode, the color flow mode, and the Doppler mode at high speed, it is necessary to change the output voltage of the transmission power supply at high speed. However, it is difficult to switch at high speed with a single power supply as shown in FIG. was there.

  In order to solve this, for example, as described in Patent Document 1, a plurality of power supplies may be used, and the power supplied by a switch may be switched. FIG. 8 shows a voltage switching method for transmission described in Patent Document 1. As shown in FIG. 8A, the transmission power supplies 5A and 5B are used, and these two power supplies are switched by the switch. As shown in FIG. 8B, when a transmission waveform having a relatively large amplitude V1 is generated in the B mode, the switch 14 is connected to the a side, and the voltage B1 is supplied from the transmission power supply 5A. In order to generate a transmission waveform with a relatively small amplitude V2 for the color flow mode, the switch 14 is connected to the b side, the output voltage B2 of the transmission power supply 5B is supplied, and VB becomes equal to B2. By repeating this operation, transmission / reception for the B mode and transmission / reception for the color flow are performed in a time-sharing manner.

Similar to that shown in FIG. 6, capacitors C1 and C2 are attached to the output sides of the transmission power supplies 5A and 5B, respectively. A capacitor C3 is attached to the output side of the switch 14. This is used as a temporary power source because a sudden power consumption occurs in the transmission pulse generator when a transmission pulse is generated, a voltage drop occurs because the internal resistance of the switch 14 is not zero, and the output voltage decreases. .
JP-A-11-290321

  In the above conventional example, in order to switch the B mode, the color flow mode and the Doppler mode at high speed, it is necessary to change the output voltage of the transmission power supply at high speed. However, in the capacitor, for example, the capacitor C3 in FIG. There is a problem that power consumption due to charge and discharge is large and the amount of heat generation increases.

  In addition to the problem of power consumption, harmonics are generated due to driving with a square wave, so even harmonic imaging, which generates images using harmonic distortion generated in vivo, is included in the transmitted waveform. There has also been a problem that the image deteriorates due to the presence of higher harmonics.

  An object of the present invention is to solve these problems, to reduce the amount of charge and discharge in a capacitor for compensating for a voltage drop, and to reduce power consumption and heat generation.

  It is another object of the present invention to suppress the generation of harmonics by making the transmission waveform closer to a sine wave than a rectangular wave.

  An ultrasonic diagnostic apparatus of the present invention includes a transmission pulse generator composed of a transformer for driving a transducer for transmitting and receiving ultrasonic waves and a switch means, and a transmission power source for supplying current to the transmission pulse generator. And a capacitor connected to the output terminal of the transmission power source, and a controller for controlling the voltage of the transmission power source. In order to solve the above problems, the primary side winding of the transformer is composed of a plurality of primary side windings having different numbers of windings, and each of the plurality of primary side windings includes two systems. A switch means is connected, and a reverse current flows from the transmission power source to each of the primary windings via the two systems of switch means.

  According to this configuration, by using a plurality of primary windings of the transformer of the transmission pulse generator, the usage of the primary winding is switched according to the drive mode, and the voltage of the transmission power supply is changed. It is possible to reduce power consumption and heat generation.

  In the ultrasonic diagnostic apparatus having the above-described configuration, the transmission power supply includes a plurality of systems, and current is supplied from the transmission power supplies of different systems to the primary windings of the plurality of systems. it can.

  Further, when a transmission pulse having a large amplitude is generated, a current can be simultaneously supplied to the multiple primary windings.

  The primary side windings are provided in two systems, and when generating transmission pulses with a small wave number, the two primary side windings are used simultaneously, and the primary side windings of one system are used as the primary side windings. Further, it is possible to apply a pulse having a pulse width shorter than that of the primary winding of the other system.

  The primary side windings are provided in two systems, and when the transmission pulse is generated, the two systems of primary side windings are used at the same time. A pulse having a shorter pulse width than that of the primary side winding of the other pulse is applied, and the short pulse is included in a pulse having a longer pulse width applied to the primary side winding of the other system. It can be configured to be controlled. Thereby, the harmonic distortion of the transmission waveform can be reduced.

  According to the ultrasonic diagnostic apparatus having the above-described configuration, by providing a plurality of primary windings in the transformer step-up transmission pulse generator, changes in the output voltage of the transmission power source between modes can be suppressed to a small level. Electric power and heat generation can be reduced.

(Embodiment 1)
FIG. 1 is a block diagram showing a transmission pulse generator 15 using a transformer and peripheral circuits constituting the ultrasonic diagnostic apparatus according to Embodiment 1 of the present invention. The transmission pulse generator 15 includes a transformer 16 and switch means 13A, 13B, 17A, and 17B. There are two primary windings of the transformer 16, switches 13A and 13B are connected to the upper winding 16a, and switches 17A and 17B are connected to the lower winding 16b. The number of lower windings is smaller than the number of upper windings. Current is supplied from the transmission power source 5 to the intermediate taps of the upper winding 16a and the lower winding 16b.

  Hereinafter, the operation will be described with reference to FIG. When outputting a transmission pulse having a relatively large amplitude for the B mode, the switch means 13A and 13B are turned on and off at the timing as in the conventional example shown in FIG. As a result, a pulse having an amplitude V1 is output to the secondary side of the transformer 16, and the vibrator 1 is driven. At this time, the output voltage VB of the transmission power supply 5 is VB1.

  In the color mode or the Doppler mode, the switch means 17A and 17B are turned on and off, and a pulse with an amplitude V2 is output to the secondary side of the transformer 16 to drive the vibrator 1. In the color mode and the Doppler mode, the output voltage VB of the transmission power supply 5 is VB2. However, since the number of windings on the transformer primary side is smaller than the number of upper windings, the number of lower windings is less than VB1. The difference in VB2 is reduced.

  As a result, the change in voltage controlled by the controller 4 is reduced, and the charge discharge charge to the capacitor (not shown) for voltage stabilization arranged on the output side of the transmission power supply 5 can be reduced. . As a result, power consumption and heat generation can be reduced.

(Embodiment 2)
FIG. 2 is a block diagram showing a transmission pulse generator 15 using a transformer and peripheral circuits constituting the ultrasonic diagnostic apparatus according to the second embodiment. Similar to the first embodiment, the transmission pulse generator 15 includes a transformer 16 and switch means 13A, 13B, 17A, and 17B. The transformer 16 has two primary windings. The upper winding 16a is connected to switching means 13A and 13B, and the lower winding 16b is connected to switching means 17A and 17B. The number of lower windings is smaller than the number of upper windings.

  In the present embodiment, transmission power supplies 18A and 18B for supplying power to the intermediate tap of the upper winding 16a and the intermediate tap of the lower winding 16b are separately provided. Therefore, the switch means 13A, 13B and the transmission power supply 18A are used in the B mode, and the switch means 17A, 17B and the transmission power supply 18B are used in the color mode and the Doppler mode. It is possible to eliminate charging and discharging of a capacitor (not shown), and to reduce power consumption and heat generation.

On the other hand, a method is also conceivable in which the primary winding of the transformer is made one system and the power source connected to the intermediate tap is switched by a switch. However, since a switch that can be switched at high speed has an impedance of about several Ω, a capacitor is required on the intermediate tap side of the switch, so that power consumption cannot be reduced.
(Embodiment 3)
FIG. 3 is a block diagram showing a transmission pulse generator 15 using a transformer and peripheral circuits constituting the ultrasonic diagnostic apparatus according to the third embodiment. Similar to the first embodiment, the transmission pulse generator 15 includes a transformer 16 and switch means 13A, 13B, 17A, and 17B. The transformer 16 has two primary windings. The upper winding 16a is connected to switching means 13A and 13B, and the lower winding 16b is connected to switching means 17A and 17B. The number of lower windings is smaller than the number of upper windings. Current is supplied from the transmission power source 5 to the intermediate taps of the upper winding 16a and the lower winding 16b.

  In the present embodiment, the circuit configuration is the same as in the first embodiment, but the sequence of the switch means 13A, 13B, 17A, and 17B is different. This will be described with reference to FIG.

  In the B mode, a relatively large amplitude is required. When the transmission pulse for the B mode is generated, the switch means 13A and 17A are turned on simultaneously, and the switch means 13B and 17B are turned on simultaneously. As a result, the amount of magnetic flux generated in the transformer 16 increases, and the voltage generated on the secondary side of the transformer also increases.

In the color mode or Doppler mode, only the switch means 13A and only the switch means 13B are turned ON. Thereby, the amplitude V2 lower than the amplitude V1 of the drive pulse in the B mode can be generated. The turn ratio of the upper winding and the lower winding is determined by the pulse amplitude required in the B mode, the color mode, and the Doppler mode. In FIG. 3B, the switch means 13A and 13B are described as being used in the color mode and the Doppler mode. However, the switch means 17A and 17B may be used according to the necessary transmission pulse amplitude.
(Embodiment 4)
FIG. 4 is a block diagram showing a transmission pulse generator 15 using a transformer and peripheral circuits constituting the ultrasonic diagnostic apparatus according to the fourth embodiment. Similar to the second embodiment, the transmission pulse generator 15 includes a transformer 16 and switch means 13A, 13B, 17A, and 17B. The transformer 16 has two primary windings. The upper winding 16a is connected to switching means 13A and 13B, and the lower winding 16b is connected to switching means 17A and 17B. The number of lower windings is smaller than the number of upper windings. Further, transmission power supplies 18A and 18B for supplying power to the intermediate tap of the upper winding 16a and the intermediate tap of the lower winding 16b are separately provided.

  In the present embodiment, the circuit configuration is the same as in the second embodiment, but the sequence of the switch means 13A, 13B, 17A, and 17B is different. This will be described with reference to FIG.

In the B mode, a relatively large amplitude is required. For this reason, it is necessary that the rise time of the waveform is short (the slew rate is fast). In the present embodiment, when the transmission pulse for the B mode is generated, the switch means 13A and 17A are simultaneously turned on, and the switch means 13B and 17B are turned on at the same time. Only ON. Thereby, the rise time of the waveform in the B mode can be shortened, and an excellent transmission pulse waveform can be output.
(Embodiment 5)
FIG. 5 is a block diagram showing a transmission pulse generator 15 using a transformer and peripheral circuits constituting the ultrasonic diagnostic apparatus according to the fifth embodiment. Similar to the second embodiment, the transmission pulse generator 15 includes a transformer 16 and switch means 13A, 13B, 17A, and 17B. The transformer 16 has two primary windings. The upper winding 16a is connected to switching means 13A and 13B, and the lower winding 16b is connected to switching means 17A and 17B. The number of lower windings is smaller than the number of upper windings. Further, transmission power supplies 18A and 18B for supplying power to the intermediate tap of the upper winding 16a and the intermediate tap of the lower winding 16b are separately provided.

  In the present embodiment, the circuit configuration is the same as in the second embodiment, but the sequence of the switch means 13A, 13B, 17A, and 17B is different. This will be described with reference to FIG.

  Harmonic imaging, which has become widespread in recent years, uses the fact that nonlinear distortion occurs in the propagation of an ultrasonic signal irradiated into the body and is captured as a harmonic component. When a harmonic signal generated in the living body is received, if the transmission waveform itself contains a harmonic, it is mixed with the harmonic generated in the living body, so that the image quality deteriorates. However, the conventional driving waveform is a rectangular wave and includes many harmonics.

  In the present embodiment, the switch means 13A is turned on, and the switch means 17A is turned on with a little delay (specifically, about 25% of the ON time of the switch means 13A). The ON time of the switch means 17A is about half of the ON time of the switch means 13A, and the switch means 13A is turned OFF after the switch means 17A is turned OFF.

  The switch means 13B and 17B also perform the same ON-OFF sequence as described above.

  The pulse generated at this time is as shown in the waveform of the transmission pulse output in FIG. 5B, which is closer to a sine wave than a conventional rectangular wave and has less harmonic components. As a result, harmonics in the living body can be extracted more in harmonic imaging.

  In the above description of the embodiment, the primary winding of the transformer constituting the transmission pulse generator is two systems, but a plurality of systems of three systems or more can be used as necessary.

  The ultrasonic diagnostic apparatus of the present invention is provided with a plurality of primary windings of the transformer boost type transmission pulse generator to suppress a change in the output voltage of the transmission power source between modes and compensate for a voltage drop. This makes it possible to reduce power consumption and heat generation in the capacitor, which is practically advantageous.

The transmission pulse generator which comprises the ultrasonic diagnosing device in Embodiment 1, and a peripheral element circuit are shown, (a) is a circuit diagram, (b) is a waveform diagram which shows the operation | movement. The transmission pulse generator which comprises the ultrasonic diagnosing device in Embodiment 2, and a peripheral element circuit are shown, (a) is a circuit diagram, (b) is a waveform diagram which shows the operation | movement. The transmission pulse generator which comprises the ultrasonic diagnosing device in Embodiment 3, and a peripheral element circuit are shown, (a) is a circuit diagram, (b) is a waveform diagram which shows the operation | movement. The transmission pulse generator which comprises the ultrasonic diagnosing device in Embodiment 4, and a peripheral element circuit are shown, (a) is a circuit diagram, (b) is a waveform diagram which shows the operation | movement. The transmission pulse generator which comprises the ultrasonic diagnosing device in Embodiment 5, and a peripheral element circuit are shown, (a) is a circuit diagram, (b) is a waveform diagram which shows the operation | movement. Block diagram of a conventional ultrasonic diagnostic apparatus for performing sector scanning The principal part in the other example of the conventional ultrasonic diagnosing device is shown, (a) is a block diagram, (b) is the waveform diagram which shows the operation | movement. Block diagram of an ultrasonic diagnostic apparatus that performs sector scanning in a conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1-1 to 1-8 Vibrator 2, 2-1 to 2-8, 15 Transmission pulse generator 3 Transmission trigger generator 4 Controller 5, 5A, 5B, 18A, 18B Transmission power supply 6-1 6-8 Reception Amplifier 7 Beamformer 8 Detector 9 Scan Converter (DSC)
10 Indicator 11, C1, C2, C3 Capacitor 12, 16 Transformer 13A, 13B, 17A, 17B, 14 Switch means 16a, 16b Primary winding

Claims (5)

A transmission pulse generator composed of a transformer and a switching means for driving a transducer for transmitting and receiving ultrasonic waves, a transmission power source for supplying current to the transmission pulse generator, and an output terminal of the transmission power source In an ultrasonic diagnostic apparatus comprising a connected capacitor and a controller for controlling the voltage of the transmission power supply,
The primary winding of the transformer is composed of a plurality of primary windings with different numbers of windings, and two switching means are connected to each of the primary windings of the plurality of windings. An ultrasonic diagnostic apparatus having a configuration in which a reverse current flows from each of the transmission power sources to each of the primary windings via a system switch.   The ultrasonic diagnostic apparatus according to claim 1, wherein the transmission power source includes a plurality of systems, and current is supplied from the transmission power sources of different systems to the primary windings of the plurality of systems.   The ultrasonic diagnostic apparatus according to claim 1, wherein when a transmission pulse having a large amplitude is generated, a current is simultaneously supplied to the plurality of primary windings.   The primary side windings are provided in two systems, and when generating a transmission pulse with a small wave number, the two primary side windings are used at the same time. The ultrasonic diagnostic apparatus according to claim 1, wherein a pulse having a shorter pulse width than that of the primary winding of the system is applied.   The primary side windings are provided in two systems, and when the transmission pulse is generated, the two primary side windings are used at the same time, and the primary side winding of one system has 1 of the other system. A pulse having a shorter pulse width than that of the secondary winding is applied, and the short pulse is controlled to be included in a pulse having a long pulse width applied to the primary winding of the other system. The ultrasonic diagnostic apparatus according to claim 1.

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