JP5002363B2 - Ultrasonic diagnostic apparatus and transformer circuit - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus for diagnosing a subject using ultrasonic waves radiated from an ultrasonic transducer, and a transformer circuit suitable for use in transmission / reception of ultrasonic signals in such an ultrasonic diagnostic apparatus. About.

  A magnetic flux addition type linear driver for driving an ultrasonic transducer in an ultrasonic diagnostic apparatus is known (see Patent Document 1).

  This type of driver excites signals of various levels in the secondary winding by adding magnetic fluxes arbitrarily generated in each of the plurality of primary windings. For this operation, the driver includes a core having a plurality of axes, and includes a transformer in which a plurality of primary windings and secondary windings are separately wound around the axes.

Now, in order to input the reception signal output from the ultrasonic transducer to the reception circuit via the secondary winding, the impedance of the secondary winding is lowered by shorting the primary winding. .
JP 2003-275205 A

  However, since the primary winding and the secondary winding are not on the same axis, the leakage inductance is large. For this reason, even if the primary winding is short-circuited, the impedance remains in the secondary winding, resulting in a problem that the received signal is attenuated and the sensitivity is deteriorated.

  The present invention has been made in consideration of such circumstances, and an object thereof is to reduce attenuation of a received signal when passing through a secondary winding.

  To achieve the above object, the present invention provides a core having at least three shafts magnetically coupled to each other, a secondary winding wound around one of the shafts, and one end of the secondary winding. And an ultrasonic transducer connected to the other end of the secondary winding, and means for acquiring information for diagnosis on the subject based on an electrical signal output by the ultrasonic transducer during a reception period And at least two primary windings wound respectively on at least two of the shafts different from the shaft on which the secondary winding is wound, and energization of the primary winding At least two switching means for turning on / off each of the first winding and the switching so that energization to the primary winding is turned on / off in a pattern according to a desired ultrasonic waveform during a transmission period different from the reception period. Means for controlling the means and the secondary winding A shunt winding wound around the same axis, a grounding means for selectively forming a first state in which the shunt winding is grounded and a second state in which the shunt winding is not grounded; And the means for controlling the grounding means so as to be in the second state at least during the period other than the transmission period including the reception period.

In order to achieve the above object, another aspect of the present invention provides a core having at least three axes that are magnetically coupled to each other, a coil wound around one of the axes, and an ultrasonic transducer at one end and receiving. Means for acquiring information for diagnosis related to the subject based on an electrical signal output by the ultrasonic transducer during the period, and a secondary winding connected to the other end, and the secondary winding of the shafts At least two primary windings wound respectively on at least two of the different shafts from which the wire is wound, and at least two switching means for respectively turning on / off the energization of the primary windings And a shunt winding wound on the same axis as the secondary winding, and a grounding means for selectively forming a first state in which the shunt winding is grounded and a second state in which the shunt winding is not grounded. A circuit was constructed.

  According to the present invention, it is possible to reduce the attenuation of the received signal when passing through the secondary winding.

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

  FIG. 1 is a diagram showing a configuration of an ultrasonic diagnostic apparatus according to this embodiment. In FIG. 1, the characteristic elements of the present invention are mainly shown, and some of the elements included in a conventional ultrasonic diagnostic apparatus are not shown.

  As shown in FIG. 1, the ultrasonic diagnostic apparatus according to this embodiment includes an ultrasonic transducer 1, a transformer circuit 2, a transmission waveform generation circuit 3, a preamplifier 4, a reception beamformer 5, and a digital scan converter (DSC) 6. , CRT 7 and system control unit 8.

  The ultrasonic transducer 1 is excited according to the transmission signal output from the transformer circuit 2 and radiates an ultrasonic signal. The ultrasonic transducer 1 outputs an electrical signal corresponding to the incident ultrasonic transducer as a reception signal.

  The transformer circuit 2 generates a transmission signal having an arbitrary waveform under the drive of the transmission waveform generation circuit 3. The transformer circuit 2 transmits the reception signal output from the ultrasonic transducer 1 to the preamplifier 4.

  The transmission waveform generation circuit 3 turns on / off a switch (described later) built in the transformer circuit 2 so that a transmission signal having a desired pattern can be obtained.

  The preamplifier 4 includes a differential amplifier X1 and diodes D1 and D2. The differential amplifier X1 amplifies the received signal input from the transformer circuit 2 so that the signal level becomes a level suitable for processing in the subsequent stage. Anti-parallel diodes D1, D2 protect differential amplifier X1 from transmitted high voltage pulses.

  Although only one ultrasonic transducer 1, transformer circuit 2 and preamplifier 4 are shown in FIG. 1, a plurality of sets are actually provided in the same connection state as shown above. It has been. The reception signals output from the plurality of preamplifiers 4 are all input to the reception beamformer 5.

  The reception beamformer 5 obtains an echo signal related to a required reception beam by delay-adding the plurality of reception signals input as described above.

  The digital scan converter 6 converts the echo signal obtained by the reception beamformer 5 into a signal suitable for display on the CRT 7.

  The CRT 7 displays an image represented by a signal output from the digital scan converter 6. The CRT 7 can be replaced with other types of display devices such as a liquid crystal display.

  The system control unit 8 includes, for example, a computer, and comprehensively controls each unit of the ultrasonic diagnostic apparatus. The system control unit 8 includes control functions for realizing various operations included in a conventional ultrasonic diagnostic apparatus. In addition, the system control unit 8 generates transmission waveform data representing a transmission waveform shape, a transmission delay time, a waveform duration, a transmission frequency, a transmission voltage level, and the like based on the set conditions, and a transmission waveform generation circuit 3 To output.

  As shown in FIG. 1, the transformer circuit 2 includes primary windings N1A, N1B, N2A, N2B, N3A, N3B, secondary winding NT, shunt winding NS, switches Q1, Q2, Q3, Q4, Q5, Includes Q6, Q7, Q8 and power supplies V1, V2, V3.

  The primary windings N1A, N1B, N2A, N2B, N3A, N3B, the secondary winding NT, and the shunt winding NS are each wound around the same core. FIG. 2 is a perspective view schematically showing the structure of the core and the winding state of each winding.

  As shown in FIG. 2, the core C is configured by magnetically coupling four poles K1, K2, K3, and K4 to each other.

  The primary windings N1A and N1B respectively correspond to two portions sandwiching the center tap in the winding N1 wound around the pole K1, which is the primary pole. The primary windings N2A and N2B respectively correspond to two portions sandwiching the center tap in the winding N2 wound around the pole K2, which is the primary pole. The primary windings N3A and N3B correspond to two portions sandwiching the center tap in the winding N3 wound around the pole K3 that is the primary pole, respectively. The secondary winding NT and the shunt winding NS are both wound around a pole K4 that is a secondary pole. However, the secondary winding NT and the shunt winding NS are electrically insulated from each other.

  One end of the primary winding N1A is connected to one end of a switch Q1 for generating a positive pulse. One end of the primary winding N1B is connected to one end of a switch Q2 for generating a negative pulse. The other ends of the primary windings N1A and N1B are connected to the power source V1. The other ends of the switches Q1 and Q2 are grounded.

  One end of the primary winding N2A is connected to one end of a positive polarity pulse generating switch Q3. One end of the primary winding N2B is connected to one end of a switch Q4 for generating a negative pulse. The other end between the primary windings N2A and N2B is connected to the power source V2. The other ends of the switches Q3 and Q4 are grounded.

  One end of the primary winding N3A is connected to one end of a positive pulse generating switch Q5. One end of the primary winding N3B is connected to one end of a switch Q6 for generating a negative pulse. The other end between the primary windings N3A and N3B is connected to the power source V3. The other ends of the switches Q5 and Q6 are grounded.

  The secondary winding NT has one end connected to the ultrasonic transducer 1 and the other end connected to the preamplifier 4.

  The shunt winding NS has one end connected to one end of a shunt switch Q7 and the other end connected to one end of a shunt switch Q8. The other ends of the switches Q7 and Q8 are grounded.

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

  The transmission waveform generation circuit 3 controls the transformer circuit 2 so as to repeatedly output a transmission signal at a period corresponding to a predetermined transmission frequency. At the time of this transmission, the transmission waveform generation circuit 3 keeps the switches Q7 and Q8 off. For this reason, since both ends of the shunt winding NS are open, no contribution is made to the output of the transmission signal.

  Now, by alternately turning on / off a pair of switches corresponding to one pole, a pulse magnetic flux is generated on that pole. That is, for example, by alternately turning on / off the switches Q1 and Q2, a pulse magnetic flux is generated at the pole K1. As a result, a pulse magnetic flux obtained by adding the pulse magnetic fluxes generated in the poles K1, K2, and K3 is generated in the pole K4, and a pulse signal having a level corresponding to this is excited in the secondary winding NT. This pulse signal is supplied from the transformer circuit 2 to the ultrasonic transducer 1 as a transmission signal. Therefore, the transmission waveform generation circuit 3 turns on / off the switches Q1 to Q6 with a pattern corresponding to a desired transmission waveform.

  The ultrasonic echo is received during the periodic transmission as described above. Therefore, after the transmission is completed, the transmission waveform generation circuit 3 turns on both the switches Q7 and Q8 as shown in FIG. Then, since the shunt winding NS is short-circuited (grounded), the impedance of the secondary winding NT is lowered. This lowered impedance is smaller than the impedance of the secondary winding NT when all of the primary windings N1A, N1B, N2A, N2B, N3A, and N3B are short-circuited. As a result, the leakage inductance is small, that is, the magnetic coupling is dense, and the attenuation of the received signal when passing through the secondary winding NT can be reduced.

  As shown in FIG. 3, the transmission waveform generation circuit 3 turns off the switches Q7 and Q8 before starting the next transmission to release the shunt. Note that the period during which the switches Q7 and Q8 are turned on only needs to include at least the period during which reception is to be performed.

  As described above, according to the present embodiment, it is possible to efficiently prevent sensitivity deterioration by an inexpensive and space-saving circuit configuration in which the shunt winding NS and the two low-breakdown-voltage switches Q7 and Q8 are added.

  Further, according to the present embodiment, since both ends of the shunt winding NS are switched, even when a MOSFET is used as a switching element, switching can be performed for a bipolar transmission pulse having a parasitic diode.

  This embodiment can be variously modified as follows.

  The shunt winding NS may not be provided with any one of the switches Q7 and Q8.

  The number of primary poles and the number of primary windings may be arbitrary as long as they are two or more.

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

The figure which shows the structure of the ultrasonic diagnosing device which concerns on one Embodiment of this invention. The perspective view which shows typically the structure of a core, and the winding state of each winding. The figure which shows the on / off timing of switches Q7 and Q8.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ultrasonic transducer, 2 ... Transformer circuit, 3 ... Transmission waveform generation circuit, 4 ... Preamplifier, 5 ... Reception beam former, 6 ... Digital scan converter (DSC), 7 ... CRT, 8 ... System control part, C ... Core, K1, K2, K3, K4 ... Pole, N1, N2, N3 ... Winding, N1A, N1B, N2A, N2B, N3A, N3B ... Primary winding, NS ... Shunt winding, NT ... Secondary Winding, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8 ... switch, 1 ... ultrasonic transducer, V1, V2, V3 ... power supply.

Claims (4)

A core having at least three axes magnetically coupled to each other;
A secondary winding wound around one of the shafts;
An ultrasonic transducer connected to one end of the secondary winding;
Means for connecting to the other end of the secondary winding and acquiring information for diagnosis related to a subject based on an electrical signal output by the ultrasonic transducer during a reception period;
At least two primary windings each wound around at least two of the shafts different from the windings of the secondary windings;
At least two switching means for turning on / off the energization of the primary winding, respectively;
Means for controlling the switching means so that energization to the primary winding is turned on / off in a pattern according to a desired ultrasonic waveform in a transmission period different from the reception period;
A shunt winding wound on the same axis as the secondary winding;
Grounding means for selectively forming a first state of grounding the shunt winding and a second state of not grounding;
Means for controlling the grounding means to be in the first state during the transmission period and to be in the second state during a period other than the transmission period including at least the reception period. An ultrasonic diagnostic apparatus characterized by the above.   2. The grounding device according to claim 1, wherein both ends of the shunt winding are grounded in the first state, and neither end of the shunt winding is grounded in the second state. Ultrasonic diagnostic equipment. A core having at least three axes magnetically coupled to each other;
Wound around one of the shafts, the ultrasonic transducer is at one end, and the other end has a means for acquiring information for diagnosis related to the subject based on the electrical signal output by the ultrasonic transducer during the reception period Secondary windings connected to each other ;
At least two primary windings each wound around at least two of the shafts different from the windings of the secondary windings;
At least two switching means for turning on / off the energization of the primary winding, respectively;
A shunt winding wound on the same axis as the secondary winding;
A transformer circuit comprising ground means for selectively forming a first state in which the shunt winding is grounded and a second state in which the shunt winding is not grounded.   The grounding means grounds both ends of the shunt winding in the first state, and does not ground both ends of the shunt winding in the second state. Transformer circuit.

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