JP3571587B2 - Ultrasound diagnostic apparatus having a pulse generation circuit - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus mainly used for medical use, and in particular, to a pulse generating circuit for generating a pulse for driving an ultrasonic transducer.The present invention relates to an ultrasonic diagnostic apparatus including:
[0002]
[Prior art]
The ultrasonic diagnostic apparatus irradiates an ultrasonic wave to an object, images a reflected echo reflected from the object as a tomographic image of the object, and performs medical diagnosis. FIG. 6 shows an example of a pulse generator (pulse generator) for driving a narrow-band ultrasonic transducer in a conventional ultrasonic diagnostic apparatus.
In this conventional pulse generating circuit 31, a half-wave output pulse generated by an input pulse is applied to an ultrasonic transducer 32 in an ultrasonic probe (not shown).
[0003]
Specifically, an input pulse from a pulse control unit (not shown) is applied from an input pulse input terminal to a gate of a field-effect transistor (abbreviated as FET) 35 through a capacitor 21 in series with the input pulse input terminal. The drain of the FET 35 is connected to a high voltage power supply terminal + HV via a first winding 33a of a transformer 33 and a resistor 34 connected in parallel to the first winding 33a. The source of the FET 32 is connected to the ground. The winding start side of each winding of the transformer 35 is indicated by a dot.
[0004]
The ultrasonic transducer 32 is connected to the second winding 33b of the transformer 33, and the matching coil 20 is connected in parallel to the ultrasonic transducer 32, and is output from the second winding 33b. Impedance matching for efficiently transmitting the output pulse to the ultrasonic transducer 32 as a specific center frequency fo is performed.
[0005]
The lower the center frequency fo, the deeper the tomographic image is obtained, but the lower the resolution. Conversely, the higher the center frequency fo, the higher the resolution, but the deeper the tomographic image cannot be obtained. Therefore, a plurality of ultrasonic probes having different center frequencies fo according to the diagnosis are required.
[0006]
By the way, recently, a broadband ultrasonic transducer having no peak at the center frequency fo and having flat characteristics from a low frequency band to a high frequency band has been developed. Also, development of an ultrasonic probe that has good resolution using a wideband ultrasonic transducer and that can obtain a tomographic image of a deep part has been promoted.
[0007]
When a broadband ultrasonic transducer is driven, the frequency band is narrowed if a matching coil 20 as shown in FIG. 6 is connected. If driving is performed with a half-wave output pulse as in the related art without the matching coil 20, the characteristics of the cable through which the output pulse is transmitted become equivalent to those of a low-pass filter, and the high-frequency components of the pulse are attenuated.
[0008]
Therefore, the pulse generating circuit 41 shown in FIG. 7 drives the ultrasonic transducer 42 in a wide band with one positive and negative output pulse (driving pulse).
In the pulse generation circuit 41, a first input pulse from a pulse control unit (not shown) is applied from a first input pulse input terminal to a gate of a field effect transistor (abbreviated as FET) 22a via a capacitor 21a in series with the first input pulse. The gate of the FET 22a is connected to ground via a resistor 23a, and the drain of the FET 22a is connected to a high voltage via a first winding 24a of the pulse transformer 24 and a resistor Ra connected in parallel to the first winding 24a. And the source of the FET 22a is connected to the ground.
[0009]
The second input pulse is applied from a second input pulse input terminal to a gate of a field effect transistor (abbreviated as FET) 22b via a capacitor 21b in series with the second input pulse, and the gate of the FET 22b is connected via a resistor 23b. The drain of the FET 22b is connected to the high-voltage power supply terminal + HV via the second winding 24b of the pulse transformer 24 and the resistor Rb connected in parallel to the second winding 24b. The source is connected to ground.
A wide-band ultrasonic transducer 42 is connected to the third winding 24c of the pulse transformer 24.
[0010]
Also, the ends of the first winding 24a and the second winding 24b of the pulse transformer 24 connected to the FETs 22a and 22b are reversed, and the first input pulse turns on the FET 22a to turn on the first winding. The direction of the current flowing through the winding 24a is opposite to the direction of the current flowing through the second winding 24b when the FET 22b is turned on by the second input pulse applied after the first input pulse. Due to the phase current, one output pulse having the waveform shown in FIG. 7 is output from the third winding 24c.
In this conventional example, the resistances Ra and Rb are set to the same resistance value.
[0011]
When the broadband ultrasonic vibrator 42 is driven by one positive and negative output pulse by the pulse generation circuit 41 shown in FIG. 7, the power in the low frequency component slightly decreases, but the high frequency component in which attenuation by the cable is expected is reduced. There is an advantage that the power of can be increased.
In general, the sharper the rise of the output pulse, the more high frequency components it has. Therefore, in order to drive the ultrasonic transducer 42 over a wide band, a pulse generator with a fast rise is required.
[0012]
[Problems to be solved by the invention]
In order to employ a wide-band ultrasonic transducer 42 and obtain an echo signal with good resolution, a high-voltage drive pulse is required and a fast rising pulse needs to be generated. This was not enough.
[0013]
Further, in addition to the pulse generating circuit 41 for driving the broadband ultrasonic vibrator 42, the conventional matching having a peak at the center frequency focoilIt is desirable to realize a pulse generation circuit having a function of applying a half-wave drive pulse to the attached ultrasonic transducer 32, but if this function is further provided, the pulse generation circuit becomes large-scale. There is a problem.
[0014]
(Object of the invention)
The present invention has been made in view of the above points, and has a steep waveform suitable for driving a wide-band ultrasonic vibrator, and can drive a narrow-band ultrasonic vibrator, and can be realized with a simple configuration. A first object is to provide an ultrasonic diagnostic apparatus including a pulse generation circuit.
[0015]
It is a second object of the present invention to provide a pulse generation circuit which has a steep waveform suitable for driving a wideband ultrasonic vibrator and can drive a conventional ultrasonic vibrator and can be realized with a simple configuration. I do.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a method in which a pulse current is supplied to a primary winding of a transformer to drive an ultrasonic transducer, and a pulse current generated in a secondary winding is supplied to the ultrasonic transducer. In an ultrasonic diagnostic apparatus having a pulse generating circuit to be applied,
The primary winding is composed of first and second windings, and a first pulse-like current is applied only to the first winding, and a pulse-like current generated in the secondary winding is applied to an ultrasonic vibrator. To be applied to
A first pulsed current is passed through the first winding, a second pulsed current is passed through the second winding with a delay from the first pulsed current, and a second pulsed current is passed through the second pulsed current. It is possible to generate a pulsed current having a polarity opposite to that of the case where the first pulsed current is applied to the winding,
By making the value of the damping resistor connected in parallel with the first winding smaller than the value of the damping resistor connected in parallel with the second winding,
By applying a first pulse-like current only to the first winding and applying a pulse-like current generated in the secondary winding to the ultrasonic vibrator, a half-wave pulse generated in this secondary winding is obtained. A narrow-band ultrasonic vibrator can be driven by the pulse-shaped current, and the first and second pulse-shaped currents are supplied to the first and second windings to generate two pulse-shaped pulses having opposite polarities generated in the secondary winding. A single pulsed current formed by the current can be applied to the broadband ultrasonic vibrator to drive it, and the value of the damping resistor connected in parallel with the first winding can be changed. By making the value smaller than the value of the damping resistor connected in parallel to the second winding, the pulse-like current generated in the secondary winding can be made to have a steep waveform having a high peak value.
[0017]
Further, a pulse setting means provided in the ultrasonic probe connected to the ultrasonic diagnostic apparatus,
By providing pulse control means for controlling generation of the first pulse-like current and the second pulse-like current according to the pulse setting means,
According to the pulse setting means provided in the ultrasonic probe, the pulse control means provided in the ultrasonic diagnostic apparatus controls the flow of the pulsed current through the first winding and the second winding. One positive / negative pulse is output from the third winding, so that a wide-band ultrasonic transducer can be driven. Further, when the pulse control means controls the flow of the pulse current only through the first winding according to the pulse setting means, it is possible to drive a narrow-band ultrasonic transducer.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First Embodiment)
1 to 4 relate to a first embodiment of the present invention. FIG. 1 shows an overall configuration of an ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 shows main components such as a pulse generation circuit in FIG. 3 shows an operation explanatory view, and FIG. 4 shows a T-shaped equivalent circuit of FIG.
[0020]
An ultrasonic diagnostic apparatus 1 according to the first embodiment of the present invention shown in FIG. 1 includes a first ultrasonic probe 2A, a second ultrasonic probe 2B, and an ultrasonic probe 2I (I = A, B). ) Are selectively detachably connected to each other, and an ultrasonic observation device 3 for generating an ultrasonic image, and a monitor 4 for receiving a video signal output from the ultrasonic observation device 3 and displaying a corresponding ultrasonic image It is composed of
[0021]
The ultrasonic probe 2I has a probe main body 6 provided with an ultrasonic transducer 5I, a cable 7 extending from the probe main body 6, and a connector 8 provided at a rear end of the cable 7. Reference numeral 8 can be detachably connected to the connector receiver 9 of the ultrasonic observation apparatus 3.
[0022]
In the present embodiment, for example, the ultrasonic transducer 5A of the first ultrasonic probe 2A employs a broadband ultrasonic transducer, and the ultrasonic transducer 5B of the second ultrasonic probe 2B has a center frequency. A narrow-band ultrasonic transducer suitable for driving at fo is employed, and a matching coil 20 is connected in parallel to the ultrasonic transducer 5B.
[0023]
Further, for example, a connector 8 of each ultrasonic probe 2I is provided with, for example, a pulse setting unit (pulse setting information generating unit) 10I as means for generating identification information unique to the ultrasonic transducer 5I provided in each ultrasonic probe 2I. Then, the pulse setting information from the pulse setting unit 10I is sent to the ultrasonic observation device 3, and the ultrasonic observation device 3 performs a drive suitable for the ultrasonic transducer 5I provided on the connected ultrasonic probe 2I. Have to be able to.
[0024]
The ultrasonic observation apparatus 3 includes a pulse generation circuit (or transmission circuit) 11 for applying a drive pulse (transmission pulse) to the ultrasonic transducer 5I of the connected ultrasonic probe 2I to emit ultrasonic waves, and a living body side. And a signal processing circuit 12 for receiving and processing the echo signal output from the ultrasonic transducer 5I in response to the reflected ultrasonic wave to generate a standard video signal. The video signal is input to the monitor 4, and an ultrasonic tomographic image is displayed on the display surface of the monitor 4.
[0025]
The pulse generation circuit 11 includes a pulse generation unit 13 and a pulse control unit 14, and the pulse generation unit 13 has a circuit configuration as shown in FIG.
This pulse generator 13 is obtained by removing the resistor Ra parallel to the first winding 24a from the resistor R1 and removing the resistor Rb parallel to the second winding 24b in the pulse generating circuit 41 of FIG.
[0026]
More specifically, the first input pulse from the pulse control unit 14 is applied to the gate of a field effect transistor (abbreviated as FET) 22a through a series capacitor 21a to the first input pulse input terminal to which the first input pulse is applied. The gate of the FET 22a is connected to the ground via a resistor 23a, and the drain of the FET 22a has a first winding 24a and a first winding 24a constituting a primary winding of a transformer 24 having a wide band input / output characteristic. The first winding 24a is connected to a high-voltage power supply terminal + HV via a damping resistor R1 connected in parallel, and the source of the FET 22a is connected to the ground.
[0027]
A second input pulse to which a second input pulse is applied is applied to the gate of a field effect transistor (abbreviated as FET) 22b through a series capacitor 21b at the input terminal of the second input pulse. The gate of the FET 22b is connected to a resistor 23b. The drain of the FET 22b is connected to a high-voltage power supply terminal + HV via a second winding 24b constituting a primary winding of the transformer 24, and the source of the FET 22b is connected to the ground. I have.
[0028]
As shown in FIG. 2, a damping resistor R1 sufficient to suppress pulse ringing is connected to both ends of the first winding 24a, and a damping resistor is connected to both ends of the second winding 24b. There is no configuration.
[0029]
The third winding 24c constituting the secondary winding of the transformer 24 is connected to the ultrasonic transducer connection terminal of the connector receiver 9, and is connected to the ultrasonic transducer 5I provided on the connected ultrasonic probe 2I. An output pulse can be applied from the third winding 24c of the transformer 24.
[0030]
Further, both ends of the first winding 24a connected to the FET 22a and the power supply terminal + HV, and both ends of the second winding 24b connected to the FET 22b and the power supply terminal + HV are opposite to each other. The direction of the current flowing through the first winding 24a when the pulse 22 turns on the FET 22a is opposite to the direction of the current flowing through the second winding 24b when the FET 22b turns on with the second input pulse. ing.
The first winding 24a and the second winding 24b of the transformer 24 are set to have almost the same characteristics (for example, bi-filar winding).
[0031]
Further, in the present embodiment, the input pulse applied to the first input terminal and the second input terminal can be controlled by the pulse control unit 14 and can be controlled by the signal of the pulse setting unit 10I. .
[0032]
In the specific example shown in FIG. 2, the pulse setting unit 10I is formed of a resistor. For example, the probe 2A is formed of a resistor having a resistance value ra, and the probe 2B is formed of a resistor having a resistance value of rb (here, ra ≠ rb). . Then, the pulse control unit 14 controls the generation of a pulse suitable for driving the corresponding ultrasonic transducer 5A or 5B in accordance with the resistance value ra or rb.
[0033]
In other words, as shown in FIG. 2, in the case of the pulse setting unit 10A using the resistor having the resistance value ra, the pulse control unit 14 switches the first pulse output terminal from the first pulse output terminal so as to drive the ultrasonic transducer 5A having a wide band. , And a second pulse is generated from the second pulse output terminal after the first pulse, specifically, at the falling of the first pulse.
[0034]
Further, in the case of the pulse setting unit 10B using the resistance having the resistance value rb, the pulse control unit 14 generates only the first pulse from the first pulse output terminal so as to drive the narrow-band ultrasonic transducer 5B. Then, the pulse generator 13 is driven by the first pulse. The pulse setting unit 10I may be formed by using an electrical means using a memory such as a ROM, or an optical means such as a bar code, in addition to the resistor.
[0035]
In the present embodiment, a resistor R1 connected in parallel to the first winding 24a and a resistor R2 connected in parallel to the second winding 24a (in the specific example of FIG. In the specific example of FIG. 2, the resistance value is set to R1 <R2 (for the sake of simplicity, the resistance values of the resistors R1 and R2 are also represented by R1 and R2, respectively). are doing.
[0036]
Next, the operation of the present embodiment will be described.
When an ultrasonic probe 2A having a built-in ultrasonic transducer 5A for a wide band is used to irradiate ultrasonic waves to a diagnostic object such as a living body to obtain an ultrasonic tomographic image, FIG. The ultrasonic probe 2A is connected to the ultrasonic observation device 3 as described above.
Then, the resistance value ra of the resistor forming the pulse setting unit 10A of the ultrasonic probe 2A is read by the pulse control unit 14, and in this case, the pulse control unit 14 drives the broadband ultrasonic transducer 5A. The input pulse is output to the pulse generator 13.
[0037]
Then, the pulse control unit 14 applies the first input pulse to the FET 22a via the capacitor 21a at the transmission timing, turns on the FET 22a, and supplies the power to the first winding 24a connected to the drain of the FET 22a. By causing a current to flow from the terminal + HV, a pulse-like output pulse (Pa for convenience) is generated in the third winding 24c electromagnetically coupled to the first winding 24a.
[0038]
In this case, a damping resistor R1 is connected to the first winding 24a, so that occurrence of ringing can be suppressed. When the first input pulse is applied to the FET 22a, the other FET 22b is in the OFF state (where no second input pulse is generated). Therefore, when a current flows through the first winding 24a, the second FET 22b is turned off. Both ends of the winding 24b are equivalent to the released state.
[0039]
In this state, when an electric current is supplied to the first winding 24a to generate an output pulse (drive pulse) in the third winding 24c, a steep rising waveform and a high voltage as described later (see FIG. 3) are obtained. Can be.
[0040]
At the time of falling of the first input pulse, the pulse controller 14 applies a second input pulse to the FET 22b via the capacitor 21b to turn on the FET 22b, and the second input pulse connected to the drain of the FET 22b. A current flows from the power supply terminal + HV to the winding 24b, and a pulse-like output pulse (Pb for convenience) is generated in the third winding 24c electromagnetically coupled to the second winding 24a.
[0041]
In this case, the direction of the current flowing through the second winding 24a is opposite to the direction of the current flowing through the first winding 24a. Therefore, the pulse-like output pulse induced in the third winding 24c is An output pulse (referred to as Pb) having a polarity opposite to that of the output pulse Pa is generated.
In this case, since no damping resistor is connected to both ends of the second winding 24a, the output pulse Pb induced in the third winding 24c has ringing, but damping to suppress ringing ( Resistance), resulting in a steep waveform.
[0042]
Then, one output pulse (a waveform having a steeper waveform and ringing on the second half-wave side than the output pulse shown in FIG. 7) obtained by combining these output pulses Pa and Pb passes through the cable of the ultrasonic probe 2A. The ultrasonic wave is applied to the ultrasonic transducer 5A.
[0043]
In this case, due to the capacitive load of the cable, the rising waveform at the end of one wave of the output pulse is blunted (the steep rising waveform is somewhat less steep), and ringing is suppressed, and the output pulse is suppressed. This is applied to the vibrator 5A.
[0044]
When a current flows through the first winding 24a by the first input pulse, the resistance Rb is connected to both ends of the second winding 24b in the conventional example of FIG. While energy is consumed by the winding 24b, in the present embodiment, since no resistance is connected to both ends of the second winding 24b, energy is prevented from being consumed by the second winding 24b. Therefore, the voltage (peak value) of the output pulse induced in the third winding 24c can be made larger than that of the conventional example, and a steep waveform can be obtained.
[0045]
Therefore, as compared with the case of the conventional example of FIG. 7, the peak value of the output pulse Pa of the first half wave of one wave can be increased and the waveform can be sharpened, and the rising portion of the output pulse Pb in the latter half of one wave can be reduced. It can be reduced or eliminated. That is, according to the present embodiment, it is possible to transmit and receive ultrasonic waves with a simple configuration at a high voltage and with a higher frequency component held.
[0046]
The pulse-like ultrasonic wave emitted from the ultrasonic transducer 5A is reflected at a portion where the acoustic impedance of the observation object changes, becomes a reflected ultrasonic wave, is received again by the ultrasonic transducer 5A, and is an electric signal, that is, an echo signal. The signal is input to the signal processing circuit 12, amplified, detected, coordinate-converted, and the like, and displayed on the monitor 4 as an ultrasonic tomographic image.
[0047]
In this case, as described above, since an echo signal having a higher voltage and higher frequency components can be obtained as compared with the conventional example, an ultrasonic tomographic image with good image quality suitable for diagnosis with high resolution can be obtained. Can be obtained.
[0048]
On the other hand, when performing ultrasonic diagnosis by connecting the ultrasonic probe 2B, the ultrasonic probe 2B is connected to the ultrasonic observation device 3.
Then, the resistance value rb of the resistor forming the pulse setting unit 10B of the ultrasonic probe 2B is read by the pulse control unit 14, and in this case, the pulse control unit 14 drives the narrow-band ultrasonic transducer 5B. Is output to the Hals generating unit 13.
[0049]
Then, at the transmission timing, the pulse control unit 14 applies a first input pulse to the FET 22a via the capacitor 21a, turns on the FET 22a, and supplies the power to the first winding 24a connected to the drain of the FET 22a. By causing a current to flow from the terminal + HV, a pulse-like output pulse is generated in the third winding 24c electromagnetically coupled to the first winding 24a.
In this case, a damping resistor R1 is connected to the first winding 24a, so that occurrence of ringing can be suppressed.
[0050]
Then, this output pulse is applied to the ultrasonic transducer 5B via the cable of the ultrasonic probe 2B. This ultrasonic transducer 5B has, for example, a characteristic of a center frequency fo.matchingThe coil 20 is connected, and an output pulse having a frequency component peaking at the center frequency fo is applied to the ultrasonic transducer 5B.
[0051]
In this case, the pulse control unit 14 keeps the state in which the second input pulse is not generated, so that the FET 22b is always off.
Therefore, when a current flows through the first winding 24a, both ends of the second winding 24b are in a state equivalent to a released state. A case where an output pulse is generated by causing a current to flow on the first winding 24a side in such a state will be described in detail with reference to FIG.
[0052]
FIG. 3 shows an input / output portion of the transformer 24 of FIG. 2 in an equivalent circuit. To simplify the description, it is assumed that the three windings of the transformer 24 have the same number of windings, the same self-inductance, and the same mutual inductance.
[0053]
A damping resistor R1 for suppressing pulse ringing is connected in parallel to the first winding 24a, and a damping resistor R2 is connected in parallel to the second winding 24b.
[0054]
An ultrasonic transducer 5C is connected in parallel to the third winding 24c. Here, when a voltage v1 is applied between the terminals of the first winding 24a, a current flowing through the first winding 24a is defined as i1. The voltage v2 appearing between the terminals of the second winding 24b, the current i2 flowing through the second winding 24b, the voltage v3 appearing between the terminals of the third winding 24c, and the current i3 flowing through the third winding 24c are It can be represented by the following equation.
[0055]
Here, L is the self-inductance of the three windings, and M is the mutual inductance of the three windings.
[0056]
v1 = L × d (i1) / dt + M × d (i2) / dt + M × d (i3) / dt
v2 = M × d (i1) / dt + L × d (i2) / dt + M × d (i3) / dt
v3 = M × d (i1) / dt + M × d (i2) / dt + L × d (i3) / dt
Focusing on v3, i2 and i3 actually flow in the opposite direction to the arrow in FIG.
v3 = M × d (i1) / dt−M × d (i2) / dt−L × d (i3) / dt
It becomes. At this time, if the terminals of the winding 2 are open except for the resistor R2,
v3 = M × d (i1) / dt−M / R2 × d (v2) / dt−L × d (i3) / dt
It becomes. Therefore, the value of the voltage v3 increases as the value of the resistor R2 increases. The larger the voltage v3, the more energy can be given to the ultrasonic transducer 5C. At this time, the current i1 is
v1 = L × d (i1) / dt
Therefore, if the voltage v1 is constant, it does not depend on the value of the resistor R1.
[0057]
FIG. 4 shows a T-shaped equivalent circuit by focusing only on the first winding 24a and the second winding 24b. Since L → ∞ and M → ∞ in the ideal transformer, the impedance viewed from the first winding 24a is only the parallel resistance component of the resistors R1 and R2. As described above, in order to increase the value of the voltage v3, the value of the resistor R2 must be increased. The value of the resistor R1 must be small enough to suppress pulse ringing.
[0058]
It is considered that the larger the voltage v3 applied to the inherent impedance of the ultrasonic transducer 5C, the steeper the rise of the voltage v3. Therefore, by satisfying the condition of R1 <R2 with respect to the resistors R1 and R2, the voltage v3 applied to the ultrasonic transducer 5C can be increased, and the rising of the pulse can be sharpened.
[0059]
In the specific configuration of FIG. 2, the resistor R2 corresponds to a case where the resistance value is infinite, and in this case, the ultrasonic transducer 5B is driven with a large voltage output pulse and a steep waveform. You can do it.
[0060]
According to the present embodiment, a pulse that can be driven at a high voltage with a steep waveform such as a rising edge suitable for driving a wide-band ultrasonic transducer 5A and that can also drive a narrow-band ultrasonic transducer 5B. The ultrasonic diagnostic apparatus 1 in which the generation circuit 11 is realized with a simple configuration can be realized.
[0061]
(Modification of First Embodiment)
A modified example of the first embodiment will be described. In this modified example, for example, in FIG. 2, a parallel resistor R1 is connected to both ends of a first winding 24a, and a series circuit of a switch S1 and a resistor R1 is connected to both ends of the first winding 24a. .
[0062]
The pulse control unit 14 turns on the switch S1 when generating the first input pulse, and turns off the switch S1 when generating the second input pulse.
In this case, the operation when a current flows through the first winding 24a with the first input pulse is the same as that of the first embodiment. The operation when the current flows through the second winding 24b with the second input pulse is the energy consumption when the resistor R1 is connected to both ends of the first winding 24a in the first embodiment. Can be prevented, and an output pulse having a higher voltage value can be generated.
The other effects are almost the same as those of the first embodiment. In other words, according to this modification, a drive pulse having a higher voltage value can be generated, and an S / N ratio is high, and an ultrasonic tomographic image suitable for ultrasonic diagnosis with high resolution can be obtained.
[0063]
Further, as a modified example, for example, in FIG. 2, a parallel resistor R1 is connected to both ends of the first winding 24a, and a switch S1 and a resistor R1 are connected in series to both ends of the first winding 24a. A circuit is connected, and a series circuit of a switch S2 and a resistor R3 is connected to both ends of the second winding 24b.
[0064]
When generating the first input pulse, the pulse controller 14 turns on the switch S1 and turns off the switch S2.
Similarly, when generating the second input pulse, the switch S1 is turned off and the switch S2 is turned on.
Note that the resistors R1 and R3 satisfy, for example, R1 <R2. Other configurations are the same as those of the first embodiment.
[0065]
In this case, the operation when a current flows through the first winding 24a with the first input pulse is the same as that of the first embodiment. Further, the operation when a current flows through the second winding 24b with the second input pulse is slightly different from that of the first embodiment, and is applied to both ends of the first winding 24a in the first embodiment. Energy consumption when the resistor R1 is connected can be prevented, and an output pulse having a higher voltage value can be generated. Note that the ringing is suppressed as compared with the case of the first embodiment because the resistor R3 is connected.
The other effects are almost the same as those of the first embodiment.
[0066]
(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, a transformer having three windings is used as the transformer 24. In the present embodiment, instead of the transformer 24, the same characteristic having two windings as shown in FIG. , The secondary windings 26b and 27b may be connected in series to form a third winding.
[0067]
For example, a resistor R1 is connected to the first winding 26a of the transformer 26, and a resistor R2 (here, R2> R1 and R2 is infinite) is connected to the first winding 27a of the transformer 27. ) Are connected to form a second winding, which is configured as in the first embodiment (in FIG. 5, the same reference numerals as those in FIG. 3 are attached).
[0068]
According to the present embodiment, since a transformer having a simpler configuration can be employed, the cost can be further reduced. The other effects are the same as those of the first embodiment.
[Appendix]
1. Ultrasound diagnosis including a pulse generating circuit for applying a pulse current to a primary winding of a transformer and applying a pulse current generated in a secondary winding to the ultrasonic transducer to drive the ultrasonic transducer In the device,
The primary winding is composed of first and second windings, and a first pulse-like current is applied only to the first winding, and a pulse-like current generated in the secondary winding is applied to an ultrasonic vibrator. To be applied to
A first pulsed current is passed through the first winding, a second pulsed current is passed through the second winding with a delay from the first pulsed current, and a second pulsed current is passed through the second pulsed current. It is possible to generate a pulsed current having a polarity opposite to that of the case where the first pulsed current is applied to the winding,
An ultrasonic diagnostic apparatus characterized in that the value of a damping resistor connected in parallel with the first winding is smaller than the value of the damping resistor connected in parallel with the second winding.
[0069]
2. Pulse setting means provided in an ultrasonic probe connected to the ultrasonic diagnostic apparatus,
The ultrasonic diagnostic apparatus according to claim 1, further comprising a pulse control unit that controls generation of the first pulse-like current and the second pulse-like current according to the pulse setting unit.
[0070]
(Effect) One positive and negative wave pulse and half wave pulse can be selectively output. As a result, a single pulse generator can drive a broadband ultrasonic transducer and a conventional ultrasonic transducer.
[0071]
3. In a pulse generation circuit that generates a drive pulse for driving the ultrasonic transducer,
A first winding to which a first pulse current is input;
A second winding to which a second pulsed current can be input in a direction opposite to the first winding and delayed from the first pulsed current;
A transformer having a third winding in which only the first winding or a third pulse-like current is output by the first and second windings;
A pulse generation circuit in which a value of a damping resistor connected in parallel to the first winding is smaller than a value of a damping resistor connected in parallel to the second winding.
[0072]
4. Ultrasound diagnosis including a pulse generating circuit for applying a pulse current to a primary winding of a transformer and applying a pulse current generated in a secondary winding to the ultrasonic transducer to drive the ultrasonic transducer In the device,
Damping in which the primary winding is composed of first and second windings and a value of a damping resistance between both ends of the second winding is smaller than a value of a damping resistance connected between both ends of the first winding. Regulatory department,
Pulse control means for controlling a pulse current flowing through at least the primary winding in the primary winding and the second winding;
And
A first pulse-like current is applied only to the first winding, and a pulse-like current generated in the secondary winding can be applied to the ultrasonic transducer.
A first pulsed current is passed through the first winding, a second pulsed current is passed through the second winding with a delay from the first pulsed current, and a second pulsed current is passed through the second pulsed current. An ultrasonic diagnostic apparatus characterized in that a pulse-like current having a polarity opposite to that of a case where a first pulse-like current flows through a winding can be generated.
[0073]
5. In Supplementary Note 4, the damping restricting unit restricts the damping function without connecting a damping resistor between both ends of the second winding.
[0074]
6. In a pulse generation circuit that generates a drive pulse for driving the ultrasonic transducer,
A first winding to which a first pulse current is input;
A second winding to which a second pulsed current can be input in a direction opposite to the first winding and delayed from the first pulsed current;
A transformer having a third winding from which a third pulse-like current is output by the first and second windings;
A pulse generation circuit in which a value of a damping resistor connected in parallel to the first winding is smaller than a value of a damping resistor connected in parallel to the second winding.
[0075]
(Effect) By making the value of the damping resistance connected in parallel to the first winding smaller than the value of the damping resistance connected in parallel to the second winding, the voltage generated in the third winding increases. . As a result, the pulse rises steeply, and a pulse generation circuit suitable for driving a wide-band ultrasonic transducer can be provided.
[0076]
【The invention's effect】
As described above, according to the present invention, the first winding and the second windingofBy controlling the pulse current flowing through the winding,The generated pulse currentIt can be applied to and drive a narrow band or wide band ultrasonic transducer.
Also, the first windingThe value of the damping resistor connected in parallel with the second winding is smaller than the value of the damping resistor connected in parallel to the second winding.By doing so, the pulse-like current generated in the secondary winding can be made a steep waveform having a high peak value.
[0077]
Further, a pulse setting means provided in the ultrasonic probe connected to the ultrasonic diagnostic apparatus,
By providing pulse control means for controlling generation of the first pulse-like current and the second pulse-like current according to the pulse setting means,
The pulse control means provided in the ultrasonic diagnostic apparatus performs control to supply a pulse current to the first winding 1 and the second winding in accordance with the pulse setting means provided in the ultrasonic probe. As a result, one positive / negative pulse is output from the third winding, and a wide-band ultrasonic transducer can be driven. Further, when the pulse control means controls the flow of the pulse current only through the first winding according to the pulse setting means, it is possible to drive a narrow-band ultrasonic transducer.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram illustrating a configuration of a pulse generation circuit.
FIG. 3 is an explanatory diagram of an operation of a pulse generation circuit.
FIG. 4 is a diagram showing a T-shaped equivalent circuit of the transformer shown in FIG. 3;
FIG. 5 is a diagram showing a transformer according to a second embodiment of the present invention.
FIG. 6 is a circuit diagram showing a pulse generation circuit for a narrow-band ultrasonic transducer in a conventional example.
FIG. 7 is a circuit diagram showing a pulse generation circuit for a wideband ultrasonic transducer in a conventional example.
[Explanation of symbols]
1. Ultrasonic diagnostic equipment
2A, 2B ... ultrasonic probe
3. Ultrasonic observation equipment
4: Monitor
5A, 5B ... ultrasonic vibrator
6: Probe body
8 Connector
10A, 10B ... pulse setting section
11 ... Pulse generation circuit
12 ... Signal processing circuit
13 ... Pulse generator
14 ... Pulse control unit
22a, 22b ... FET
24 ... Transformer
24a: first winding
24b: second winding
24c... Third winding
R1 ... Damping resistance

Claims (2)

Ultrasound diagnosis including a pulse generating circuit for applying a pulse current to a primary winding of a transformer and applying a pulse current generated in a secondary winding to the ultrasonic transducer to drive the ultrasonic transducer In the device,
The primary winding is composed of first and second windings, and a first pulse-like current is applied only to the first winding, and a pulse-like current generated in the secondary winding is applied to an ultrasonic vibrator. To be applied to
A first pulsed current is passed through the first winding, a second pulsed current is passed through the second winding with a delay from the first pulsed current, and a second pulsed current is passed through the second pulsed current. It is possible to generate a pulsed current having a polarity opposite to that of the case where the first pulsed current is applied to the winding,
An ultrasonic diagnostic apparatus comprising a pulse generating circuit, wherein a value of a damping resistor connected in parallel with the first winding is smaller than a value of a damping resistor connected in parallel with the second winding. Pulse setting means provided in an ultrasonic probe connected to the ultrasonic diagnostic apparatus,
2. An ultrasonic diagnostic apparatus comprising a pulse generation circuit according to claim 1, further comprising pulse control means for controlling generation of said first pulse current and said second pulse current according to said pulse setting means.

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