Ultrasound diagnosis apparatus and power supply

The embodiments of the present invention relate to an ultrasound diagnosis apparatus and a power supply.

An ultrasound diagnosis apparatus transmits ultrasound waves to the inside of a subject by using an ultrasound probe having a plurality of ultrasound transducers, and based on the reflected wave (ultrasound echo) from the subject, generates tomographic image data, three dimensional image data, of the inside of the subject, and the like.

There is also a technique called Tissue Harmonic Imaging which generates ultrasound images utilizing the harmonic components (second harmonic components) of the ultrasound waves. This technique performs transmission of the ultrasound waves twice in the same direction, and then causes phase of the first transmission waves and the second transmission waves to reverse. At this time, with respect to that of the first receiving waves, the phase of the fundamental wave components of the receiving waves caused by the second transmission waves is reversed, and the second harmonic components thereof become the same phase. Therefore, when the first receiving waves and the second receiving waves are added together, the fundamental waves thereof are canceled each other, and only the second harmonic components are emphasized (doubled) to output. Thereby, it makes it possible to visualize only the second harmonic components. It makes it possible, for example, to suppress the effects of multiple reflections of the transmission waves by utilizing such the technique.

Further, there is a case that the ultrasound diagnosis apparatus has a configuration such that a power supply is connected to a primary winding of a transformer to apply a voltage thereto, and then ultrasound transducers are driven by the voltage induced in a secondary winding. According to such the configuration, the direction of the voltage applied to the primary winding is switched to reverse the polarity of the pulse induced to the secondary winding.

Patent Document

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2010-81966

Problems to be Solved by the Invention

On the other hand, since the primary winding and the secondary winding are magnetically connected in the transformer, the voltage generated in the primary winding appears as the voltage, corresponding to the winding ratio, of the secondary winding by supplying a current into the primary winding. At this time, when the electricity supply to the primary winding from the outside is terminated, counter electromotive force corresponding to the load of the primary winding is generated to cause, according to Lenz's law, to counterbalance the change of the magnetic. A voltage corresponding to the winding ratio is therefore generated in the secondary winding by the counter electromotive force. Thereby, even if the current supplied to the primary winding from the outside is terminated, the voltage of the secondary winding is not returning to 0 level (bias point) immediately, the counter electromotive force is continuously induced in the secondary winding, and the signals accompanying the counter electromotive force is continuously generated from the secondary winding. For that reason, during this time, the signal accompanying the counter electromotive force is superposed on the receiving signal from the ultrasound transducer, it has been therefore difficult to receive the reflected waves of, for example, a shallow part of the subject (hereinafter, it may refers to a “shallow part”).

The embodiments of the present invention are intended to provide an ultrasound diagnosis apparatus in which electromotive force induced in a secondary winding can be varied to zero level at high speed.

Means of Solving the Problems

The ultrasound diagnosis apparatus of the embodiments comprises a transformer, a first power source and a second power source, an ultrasound transducer, a processor, and a driving part. The transformer comprises a primary winding and a secondary winding. The first power source and the second power source are connected to the primary winding. The ultrasound transducer is driven by the voltage induced to the secondary winding, and transmits ultrasound waves to a subject, and receives reflected waves reflected by the subject to output the received signal. The processor implements processing on the received signal to generate ultrasound wave images. The driving part drives to change the voltage among a first level voltage based on the first power source, a second level voltage based on the second power source, and a third level voltage between the first level voltage and the second level voltage.

FIG. 1 It is a block diagram of an ultrasound diagnosis apparatus according to the present embodiments.

FIG. 2A It is a circuit diagram illustrating an example of a transmission circuit according to a first embodiment.

FIG. 2B It is schematic diagrams illustrating relationships between pulses to each transistor and output waveforms from a secondary winding in the first embodiment.

FIG. 2C It is a diagram illustrating an ON/OFF state of each transistor at each timing in the first embodiment.

FIG. 3A It is a circuit diagram illustrating an equivalent circuit at a predetermined timing in the first embodiment.

FIG. 3B It is a circuit diagram illustrating an equivalent circuit at a predetermined timing in the first embodiment.

FIG. 3C It is a circuit diagram illustrating an equivalent circuit at a predetermined timing in the first embodiment.

FIG. 4 It is a graph illustrating a change in pulse amplitude output from the secondary winding.

FIG. 5A It is a circuit diagram illustrating an example of a transmission circuit according to a second embodiment.

FIG. 5B It is a schematic diagram illustrating relationships between pulses to each transistor and output waveforms from a secondary wingding in the second embodiment.

FIG. 5C It is a diagram illustrating an ON/OFF state of each transistor at each timing in FIG. 5B .

FIG. 6A It is a circuit diagram illustrating an equivalent circuit at a predetermined timing in the second embodiment.

FIG. 6B It is a circuit diagram illustrating an equivalent circuit at a predetermined timing in the second embodiment.

FIG. 6C It is a circuit diagram illustrating an equivalent circuit at a predetermined timing in the second embodiment.

FIG. 6D It is a circuit diagram illustrating an equivalent circuit at a predetermined timing in the second embodiment.

FIG. 6E It is a circuit diagram illustrating an equivalent circuit at a predetermined timing in the second embodiment.

FIG. 7 It is a circuit diagram illustrating a mode for the transmission circuit according to the second embodiment.

FIG. 8 It is a circuit diagram illustrating a mode for the transmission circuit according to the second embodiment.

FIG. 9A It is schematic diagram illustrating an example of relationships between pulses to each transistor and output waveforms from the secondary winding.

FIG. 9B It is a diagram illustrating an ON/OFF state of each transistor in FIG. 9A .

FIG. 10 It is a circuit diagram illustrating an example of a transmission circuit according to a modified example.

FIG. 11A It is a circuit diagram illustrating an example of a conventional transmission circuit.

FIG. 11B It is a circuit diagram illustrating an example of a conventional transmission circuit.

First Embodiment

Firstly, the configuration of an ultrasound diagnosis apparatus according to a first embodiment will be described with reference to FIG. 1 and FIG. 2A . As shown in FIG. 1 , the ultrasound diagnosis apparatus comprises a transmission circuit 10 , a driving part 100 , an ultrasound transducer group 11 , an amplifier circuit 12 , a delay circuit 13 , an adding circuit 14 , a signal processor 15 , an image processor 16 , and a display 17 . The ultrasound diagnosis apparatus according to the present embodiment operates while switching transmission and reception of ultrasound waves at a predetermined timing.

(Transmission Circuit 10 )

Here, the configuration of the transmission circuit 10 , as well as an ultrasound transducer C 10 which configures the ultrasound transducer group 11 will be described, with reference to FIG. 2A . The transmission circuit 10 comprises a transformer K 3 , power sources VP 11 and VP 13 , transistors M 11 , M 12 , M 13 , and M 14 , and diodes D 11 , D 13 , D 21 and D 22 . The transformer K 3 comprises a primary winding LP 1 , and a secondary winding LS 1 . Also, in FIG. 2A , a dotted line shows a core part of the transformer K 3 . In the example in FIG. 2A , each of the transistors M 11 and M 13 is P-type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), and each of the transistors M 12 and M 14 is N-type MOSFET.

The power source VP 11 is connected to the source of the transistor M 11 , and the power source VP 13 is connected to the source of the transistor M 13 . Also, the sources of the transistors M 12 and M 14 are connected to a common voltage. Here, the common voltage is a voltage (ground) acts as a reference in common within a circuit. One end of the primary winding LP 1 is connected to the drain of the transistor M 11 and the drain of the transistor M 14 . Further, the diode D 11 is interposed between the one end of the primary winding LP 1 and the drain of the transistor M 11 , in order to regulate the current flow in the direction from the primary winding LP 1 to the transistor M 11 . Similarly, the other end of the primary winding LP 1 is connected to the drain of the transistor M 13 and the drain of the transistor M 12 . The diode D 13 is interposed between the other end of the primary winding LP 1 and the drain of the transistor M 13 , in order to regulate the current flow in the direction from the primary winding LP 1 to the transistor M 13 . In addition, the power supply VP 11 corresponds to a “first power supply”, and the power supply VP 13 corresponds to a “second power supply”. That is, the power supply VP 11 and the power supply VP 13 are arranged by interposing the primary winding LP 1 , and each can supply a current in the opposite direction each other. Also, the power supply VP 11 may be a power supply which generates a voltage different from the one generated from the power supply VP 13 , or may be a power supply which generates a voltage as same as the one generated from the power supply VP 13 . Further, the transistor M 11 corresponds to a “first switch”, and the transistor M 13 corresponds to a “second switch”. Furthermore, the transistor M 12 corresponds to a “third switch”, and the transistor M 14 corresponds to a “fourth switch”.

The ultrasound transducer C 10 which configures the ultrasound transducer group 11 is connected to one end of the secondary winding LS 1 and a receiving circuit (that is, the amplifier circuit 12 ). The connection part of the wirings respectively connected to the ultrasound transducer C 10 , the one end of the secondary winding LS 1 , and the receiving circuit designates a connection point P 21 . In addition, the other end of the secondary winding LS 1 is connected to the common voltage. A diode switch which is configured by the diodes D 21 and D 22 is interposed between the one end of the secondary winding LS 1 and the connecting point P 21 . The diodes D 21 and D 22 in this case are arranged so that the anode terminal of either one of these diodes and the cathode terminal of the other are connected to the same signal line.

The diodes D 21 and D 22 become ON states when, for example, a passing signal (pulse wave, or continuous wave) has amplitude of 1.4 Vpp (equivalent to the voltage±0.7V) or more, and work to pass the signal. On the other hand, when the amplitude is less than 1.4 Vpp, the diodes become OFF states, and work to terminate the signal. At the time of driving the ultrasound transducer C 10 (that is, at the time of transmitting the ultrasound waves), the signal induced in the secondary winding LS 1 passes the diode switch, since the signal has amplitude of 20 Vpp (equivalent to the voltage±10V) to 200 Vpp (equivalent to the voltage±100V). Whereas, at the time of receiving an echo signal from the ultrasound transducer C 10 , since the echo signal has amplitude of less than 1.0 Vpp (equivalent to the voltage±0.5V), the signal is terminated at the diode switch and output to the receiving circuit (that is, the amplifier circuit 12 ). In this way, when the voltage of the transmission circuit side (that is, the secondary winding LS 1 ) is lowered, arranging the diode switch makes the loads of the transmission circuit side undetectable from the receiving circuit. It means that it is possible to separate the influence on the transmission circuit side from the receiving circuit.

A limiter, which restricts any signal having a predetermined amplitude (for example, ±0.7V) or more from passing therethrough, is arranged in the input stage of the amplifier circuit 12 . In the case that the signal directed to the amplifier circuit 12 has amplitude of ±0.7V or more, this limiter restricts the signal pass through the amplifier circuit 12 .

The driving part 100 switches ON/OFF of each transistor M 11 to M 14 at each of predetermined timings, thereby controlling the kinds and directions of the voltage (primary voltage) to be applied to the primary winding LP 1 . The control of the driving part 100 will be described with reference to FIG. 2B and FIG. 2C . FIG. 2B is a schematic diagram illustrating relationships between pulses to each transistor M 11 to M 14 and the output waveforms from the secondary winding LS 1 . T 10 , T 11 and T 12 in FIG. 2B show each of the timings during a period of transmitting the ultrasound waves. As the voltage (second voltage) induced to the secondary winding LS 1 changes at each of the timings, the voltages of a plurality of levels can be output. As an example for the case, VP 111 and VP 131 in FIG. 2B show the secondary voltage induced in the secondary side (that is, the secondary winding LS 1 ) of the transformer K 3 by switching the transistors M 11 to M 14 . In FIG. 2B , the voltage VP 111 is an example of a voltage of a first level, and corresponds to the power source VP 11 , and the voltage VP 131 is an example of a voltage of a second level, and corresponds to the power source VP 13 . Further, FIG. 2C is a diagram illustrating an ON/OFF state of each transistor M 11 to M 14 at each of the timings T 10 , T 11 and T 12 in FIG. 2B . In FIG. 2C , the part shown by “◯” indicates the “ON” state.

As shown FIG. 2B , at the timing T 11 , the driving part 100 supplies pulses to the transistors M 12 and M 13 . Thereby, as shown in FIG. 2C , the transistors M 11 and M 12 become ON, and the transistors M 13 and M 14 become OFF. At the time of the equivalent circuit is shown in FIG. 3A . As shown in FIG. 3A , at the timing T 11 , the primary voltage of the power supply VP 11 is applied to the primary winding LP 1 . Thereby, as shown in FIG. 2B , the secondary voltage of VP 111 (positive electrode) is induced in the secondary winding LS 1 , and the induced voltage is applied to the ultrasound transducer C 10 .

Further, as shown in FIG. 2B , at the timing T 12 , the driving part 100 supplies pulses to the transistors M 11 and M 14 . Thereby, as shown in FIG. 2C , the transistors M 13 and M 14 become ON, and the transistors M 11 and M 12 become OFF. At the time of the equivalent circuit is shown in FIG. 3B . As shown in FIG. 3B , at the timing T 12 , the primary voltage of the power supply VP 13 is applied to the primary winding LP 1 . At this time, the direction of the current flowing into the primary winding LP 1 becomes contrary to the case of the timing T 11 shown in FIG. 3A . Therefore, as shown in FIG. 2B , the secondary voltage of VP 131 (negative electrode) is induced in the secondary winding LS 1 , and applied to the ultrasound transducer C 10 .

Also, as shown in FIG. 2B , at the timing T 10 , the driving part 100 supplies pulses to the transistors M 11 to M 14 . Thereby, as shown in FIG. 2C , the transistors M 12 and M 14 become ON, and the transistors M 11 and M 13 become OFF. At the time of the equivalent circuit is shown in FIG. 3C . As shown in FIG. 3C , at the timing T 10 , the both ends of the primary winding LP 1 are connected to the common voltage. Thereby, at the timing T 11 or T 12 , the voltage difference generated at the both ends of the secondary winding LS 1 becomes 0V by making the potential difference between the both ends of the primary winding LP 1 be 0 (the applied voltage to the primary winding LP 1 becomes 0). Thereby, as shown in FIG. 2B , the output amplitude from the secondary winding LS 1 becomes 0 which is the voltage of a third level (the voltage induced in the secondary winding becomes 0), therefore, the voltage applied to the ultrasound transducer C 10 becomes 0. That is, the voltage of the first level and the voltage of the second level are any signals other than 0, and when the voltage is switched to the 0 level of the third level voltage, the signal falls drastically if the signal is more than 0, and rises drastically if the signal is less than 0. These rising and falling of the signal are performed preferably perpendicular to the time axis, however, they may be converged to the 0 level of the third level voltage, for example, by having some tilts and/or after some ringing.

Here, switching to 0 level of the third level voltage will be described with reference to FIG. 4 . FIG. 4 is an example of a graph illustrating a change in pulse amplitude output from the secondary winding LS 1 along a time series, in the case that the voltage applied to the primary winding LP 1 is OFF. The graph G 11 in FIG. 4 shows the case, in the ultrasound diagnosis apparatus according to the present embodiment, that the control at the timing T 10 , that is when the both ends of the primary winding LP 1 are connected to the common voltage. Further, the graph G 12 shows a limiter voltage of the limiter arranged in the input stage of the amplifier circuit 12 . The graph G 12 also shows the case that the conventional transmission circuit is used, that is, the case that the both ends of the primary winding LP 1 are unconnected to the common voltage.

In this way, when the transistors M 11 and M 12 are ON, the driving part 100 induces the first level voltage to the secondary winding LS 1 . Also, when the transistors M 13 and M 14 are ON, the driving part 100 induces the second level voltage to the secondary winding LS 1 . Further, when the transistors M 12 and M 14 are ON, the driving part 100 causes to connect the both ends of the primary winding LP 1 to the common voltage to cause the output amplitude from the secondary winding LS 1 to be 0.

Here, the configuration of a conventional transmission circuit will be described with reference to FIG. 11A . FIG. 11A is a circuit diagram showing an example of a conventional transmission circuit. As shown in FIG. 11A , the conventional transmission circuit comprises a transformer including primary windings L 31 , L 32 , L 41 , and L 42 , and a secondary winding L 5 , as well as, power supplies VP 0 and VP 1 . One ends of the primary windings L 31 and L 32 are connected to the power supply VP 0 . In this case, seen from the power supply VP 0 , the primary windings L 31 and L 32 are connected so that their winding directions are different from each other. The other end of the primary winding L 31 is connected to the drain of a transistor M 31 via a diode D 31 . Similarly, the other end of the primary winding L 32 is connected to the drain of a transistor M 32 via a diode D 32 . Each source of the transistors M 31 and M 32 is connected to the common voltage.

Also, one ends of the primary windings L 41 and L 42 are connected to the power supply VP 0 , and the other ends of the primary windings L 41 and L 42 is connected to the drains of transistors M 41 and M 42 via the diodes D 31 and D 32 , respectively. These connection relationships are the same as a circuit group including the power supply VP 1 , the primary windings L 31 and L 32 , the diodes D 31 and D 32 , and the transistors M 31 and M 32 .

When any one of the transistors M 31 , M 32 , M 41 , and M 42 is ON, a current flows into any one of the primary windings L 31 , L 32 , L 41 , and L 42 to generate magnetic energy. In this case, different voltage values are applied to each of the primary windings L 31 , L 32 , L 41 , and L 42 , and their winding directions are also different from each other. Therefore, it is possible to select voltage values and polarities corresponding to the respective primary windings by supplying a current to any one of the primary windings, thereafter, a voltage is induced, based on the selected voltage value and the polarity, to the secondary winding L 5 .

Here, refer to FIG. 4 . As shown in the graph G 12 , in the case of the conventional transmission circuit (that is, the case that the both ends of the primary winding LP 1 are unconnected to the common voltage), the voltage of the secondary winding is not retuned to 0 level (bias point) until the magnetic energy generated in the primary wingding LP 1 is consumed by resistance within the circuit. Thereby, counter electromotive force is continuously induced in the secondary winding, and a signal accompanied by the counter electromotive force is continuously generated from the secondary winding. It is therefore takes about 1.3 [μsec] after the switching is performed for the voltage induced in the secondary winding LS 1 to be less than the limiter voltage of 0.7 [V]. That is, during this time, the voltage induced in the secondary winding LS 1 is applied to the connecting point P 21 , since the voltage induced in the secondary winding LS 1 passes through the diodes D 21 a D 22 . In this way, a superposed signal in which a signal from the secondary winding LS 1 is superposed on a signal from the ultrasound traducer C 10 is input to the amplifier circuit 12 .

A dynamic range, so as to adjust to an input range of the signal from the ultrasound transducer C 10 , is set for the amplifier circuit 12 . An input range (amplitude) of the signal form the secondary winding LS 1 is higher than the input range of the signal from the ultrasound transducer C 10 . There is therefore a possibility of failure when the amplifier circuit receives the signals from the secondary winding LS 1 . That is, it is difficult for the amplifier circuit 12 to receive these signals during that the signal from the secondary winding LS 1 flows into the amplifier circuit 12 by passing through the diodes D 21 and D 22 . Hence, as described above, the limiter is arranged in input stage of the amplifier circuit 12 .

During the time when the voltage induced in the secondary winding LS 1 passes through the diodes D 21 and D 22 , that is, during the time until the voltage induced in the secondary winding LS 1 is less than 0.7 [V], the signal (0.7 [V] or more) from the secondary winding LS 1 is superposed on the signal from the ultrasound transducer C 10 . Therefore, even when the signal from the ultrasound traducer C 10 is a signal of less than 0.7 [V], since the signal from the secondary winding LS 1 is superposed thereon, the superposed signal becomes of 0.7 [V] or more, and the limiter arranged in the input stage of the amplifier circuit 12 restricts the signal from passing thereto. Therefore, as long as the restriction caused by superposing signals is put, it is not allowed for the amplifier circuit 12 to receive any signals from the ultrasound traducer C 10 .

That is, in the case of switching from transmission to reception of the ultrasound waves, the reception of the ultrasound waves can not be started until the voltage induced in the secondary winding LS 1 at the time of transmitting the ultrasound waves becomes the value which can be interrupted at the diodes D 21 and D 22 . Therefore, the longer this takes, the more difficult it process an echo signal received at an earlier timing (echo signal reflected by the shallow part of the subject) at the receiving circuit side.

In general, the time until that the ultrasound wave generated from ultrasound transducer C 10 is gone and returned between the ultrasound transducer C 10 and the surface of the ultrasound probe (acoustic distance) is, depending on the probes, generally about 1 [μsec]. That is, the ultrasound wave to be received after this time (1 [μsec]) become a reflected wave reflected by the subject. It is therefore desirable for the voltage induced in the secondary winding LS 1 to be lower than the limiter voltage 0.7 [V] of the limiter arranged in the input stage of the amplifier circuit, within this time.

On the contrary, the ultrasound diagnosis apparatus according to the present embodiment cause to connect the both ends of the primary winding LP 1 to the common voltage when the voltage applied to the primary winding LP 1 is OFF, as shown in FIG. 3C . Such the operation makes the potential difference between the both ends of the primary winding LP 1 be 0 (the applied voltage to the primary winding LP 1 becomes 0), and no current flows from the outside into the primary winding LP 1 . Therefore, no magnetic energy is generated in the primary winding LP 1 . It leads that the voltage induced in the secondary winding LS 1 becomes less than the limiter voltage of 0.7 [V] after about 0.6 [μsec] from the switching, as shown by the graph G 11 in FIG. 4 . That is, the output amplitude from the secondary winding LS 1 becomes 0 at timing earlier than the case that the conventional apparatus is used. It is therefore possible to process the echo signal received at timing earlier compared to the case when the both ends of the primary winding LP 1 are unconnected to the common voltage.

As described above, in the ultrasound diagnosis apparatus according to the present embodiment, when a first voltage applied to the primary winding LP 1 is OFF, the both ends of the primary winding LP 1 are connected to the common voltage, to make the potential difference therebetween be 0, and the generation of the magnetic energy in the primary winding LP 1 is positively controlled. It makes it possible for the second voltage induced in the secondary winding LS 1 to be 0 without delay, compared to the case when the both ends of the primary winding LP 1 are unconnected to the common voltage.

Further, the transmission circuit 10 according to the present embodiment is configured such that the P-type MOSFET and the N-type MOSFET are used as a pair, even in the case the voltage is applied in any direction of the primary winding LP 1 (that is, both cases at the timings T 11 and T 12 ). In general, parts having physically different configuration such as the P-type MOSFET and the N-type MOSFET also have different characteristics. It is therefore difficult to provide parts having the same characteristics such as for both the P-type MOSFET and the N-type MOSFET. On the other hand, it is easier to provide parts having the same characteristics for the P-type MOSFETs or the N-type MOSFETs, having the same configurations, than for ones having different configurations from each other. Since, in the transmission circuit 10 according the present embodiment, the P-type MOSFET and the N-type MOSFET are used as a pair at both timings T 11 and T 12 , the configurations of the circuits at each timing are the same. Therefore, even when the voltage applied to the primary winding LP 1 is switched, it is possible to suppress the characteristic differences due to the configurational differences, and easily induce output pulses having symmetric positive/negative amplitude to the primary winding LP 1 .

In the above description, the transistors M 11 to M 14 are used as the switches, but it is not limited to this configuration as long as the configuration fulfills the functions of a switch having a desired changeover velocity. Instead of the transistors M 11 to M 14 (MOS FET), a MEMS (Micro Electro Mechanical Systems) switch may be used, for example. Further, the MOSFET used in this case is not basically limited, and may be either of a depression type or an enhancement type. It is however preferable the enhancement type in which no drain current flows when no gate voltage is applied. Furthermore, the transistor used in the present embodiment and the following embodiment is not limited to an insulated gate-type MOSFET, and may be a junction-type J-FET. Also, for example, this transistor may be a bipolar transistor. When the bipolar transistor is used, the transmission circuit 10 according to the present embodiment comprises a PNP transistor instead of the P-type MOSFET, and a NPN transistor instead of the N-type MOSFET. In addition, the gate, drain, and source are replaced by a base, emitter, and collector, respectively, and comprised by the transmission circuit 10 . The timing to turn ON the bipolar transistor is configured so that a driving current flows into the base at the timing when the above described pulses are input. For such the bipolar transistor, one having a large hybrid forward emitter (hereinafter, it refers to hFE) value is used in terms of making the driving current flowing into the base small. Otherwise, it is preferable to use one having a configuration such that Darlington connection is performed to a plurality of transistors in order to make the value of hFE large.

Further, in a case that pulses having symmetric positive/negative amplitude are output from the secondary winding, the power sources VP 11 and VP 13 may be configured with the same power source. In such the configuration, it makes is possible to simplify the configuration of the transmission circuit 10 .

The transmission circuit 10 according to the present embodiment may comprise the transistors of the same type (such as P-type, N-type, PNP-type, NPN-type) for all, for example. To be more specific, for example, by causing the transistor M 11 and the transistor M 13 to be the N-type MOSFETs, the transmission circuit 10 is configured by the transistors of the N-type MOSFETs only. Thereby, the transistor M 11 and the transistor M 13 are operated as a source follower type switch circuit in which a signal is taken out form the source side. Here, in order to drive the transistor M 11 , a driving signal to be applied to the gate of the transistor M 11 becomes a signal in which the voltage VP 111 is added to a driving signal to be applied to the transistor M 14 . Also, in order to drive the transistor M 13 , similarly, a driving signal to be applied to the transistor M 13 becomes a signal in which the voltage VP 131 is added to a driving signal to be applied to the transistor M 12 . In this way, it is preferable to select the MOSFET having a high withstand voltage between the gate and the source of the transistor, since a large voltage over 30V, for example, is applied therebetween. The MOSFET includes, for example, a GaN-MOSFET, a SiC-MOSFET, and the like, other than the Si-MOSFET. Also, since the transmission circuit 10 is configured with the transistors of the same type for all, for example, a switching element which has no type distinction between IGBT, GTO, and the like, may be used as a transistor. In a case that GTO is used as the transistor which configures the transmission circuit 10 , for example, the drain and the source, when the transmission circuit 10 is configured of the N-type MOSFET for all, are replaced with the cathode and the anode, resplectively. These may be applied similarly in the following embodiment.

The transmission circuit 10 may also be used as a single power supply. This power supply is a power supply for the ultrasound diagnosis apparatus to be connected to at least an ultrasound probe, for example. This power supply is driven by the transformer K 3 comprising the primary winding LP 1 and the secondary winding LS 1 , the first power source VP 11 and the second power source VP 13 which are connected to the primary winding LP 1 , and the voltage induced to the secondary LS 1 . This power supply comprises a driving part which drives so that the induced voltage is changed among the first level voltage based on the first power source VP 11 , the second level voltage based on the second power source VP 13 , and the third level voltage between the first level voltage and the second level voltage. This power supply may be configured by appropriately selecting, for example, from what described above about the transmission circuit 10 .

(Receiving Circuit)

Next, operations of a receiving circuit, that is, the amplifier circuit 12 , the delay circuit 13 , the adding circuit 14 , the signal processor 15 , and the image processor 16 are described as reference to FIG. 1 . The amplifier circuit 12 receives ultrasound echo signals received from each transducer of the ultrasound transducer group 11 via a signal line connected to each of the transducers. The amplifier circuit 12 implements processing such as low noise implication, buffering, or the like to finely transmit the ultrasound echo signals received from each of the transducers.

The signal amplified by the amplifier circuit 12 is provided with delay time by the delay circuit 13 , added by the adding circuit 14 , and output to the signal processor 15 . The signal phased and added by the delay circuit 13 and the adding circuit 14 , respectively, is detected by the signal processor 15 to extract an envelope. The extracted envelope is displayed on the display 17 after coordinate transformation in accordance with a section of the observation target by the image processor 16 and gradation process suitable for image display are performed. Thereby, the form information of the inside of the observation target is displayed on the display 17 in real time.

As described above, the ultrasound diagnosis apparatus according to the present embodiment positively suppresses the generation of the magnetic energy in the primary winding LP 1 by connecting the both ends of the primary winding LP 1 to the common voltage to make the potential difference between the both ends thereof be 0, when the first voltage applied to the primary winding LP 1 becomes OFF. Thereby, it is possible for the second voltage induced in the secondary winding LS 1 to be 0 without delay compared to the case that the both ends of the primary winding LP 1 are unconnected to the common voltage. It is therefore possible to start the reception promptly after transmitting ultrasound waves, and, for example, to generate an image based on the ultrasound waves reflected by a shallow part of the subject. Further, in the ultrasound diagnosis apparatus according to the present embodiment, it is the same configuration for the circuit connected to the primary winding LP 1 for a case when pulses of the positive electrode side are output and for a case when pulses of the negative electrode side are output. It makes it possible to reduce variation in performance based on the differences in the configurations of each element.

Second Embodiment

Next, an ultrasound diagnosis apparatus according to a second embodiment will be described. The ultrasound diagnosis apparatus according to the present embodiment operates while switching different modes, such as B-mode and C-mode, in time division manner. For example, B-mode is a mode to display two dimensional form images. In B-mode, one ultrasound transducer implements both transmission and reception of ultrasound waves in time division manner, and an ultrasound wave having large amplitude and a low (small) wave number is used. C-mode is a mode to analyze blood flow distribution by applying the Doppler Effect to display a two dimensional blood flow image in color. In this mode, an ultrasound wave having small amplitude and a high (large) wave number is used. In this way, these modes have amplitude and wave number of the ultrasound waves different from each other, and voltages caused to induce in the secondary winding LS 1 in accordance with the mode are different. The ultrasound diagnosis apparatus according to the present embodiment also intentionally changes the waveform of the transmitting pulse by changing the voltage applying to the ultrasound transducers during the transmission of the ultrasound waves. In order to realize such operations, the transmission circuit 10 according to the present embodiment applies voltages of different kinds, while switching in time division manner, to the primary winding LP 1 . Hereinafter, it will be described the ultrasound diagnosis apparatus according to the present embodiment will be described focusing attention to a configuration of the transmission circuit 10 which is different from that of the first embodiment, and control by the driving part 100 , as reference to FIG. 5A . FIG. 5A is a circuit diagram showing an example of the transmission circuit according to the present embodiment.

As shown in FIG. 5A , the transmission circuit 10 according to the present embodiment comprises power sources VP 15 and VP 16 , transistors M 15 and M 16 , and diodes D 15 and D 16 , in addition to the configuration shown in FIG. 2A . The transistors M 15 and M 16 have the same configuration as the transistors M 11 and M 13 , that is, as the P-type MOSFET. The power source VP 15 corresponds to a “third power source”, and the power source VP 16 corresponds to a “fourth power source”.

The source of the transistor M 15 is connected to the power source VP 15 , and the source of the transistor M 16 is connected to the power source VP 16 . The drain of the transistor M 15 is connected to one end of the primary winding LP 1 , in the same way as the transistor M 11 . Further, the drain of the transistor M 16 is connected to the other end of the primary winding LP 1 , in the same way as the transistor M 13 . The diode D 15 in interposed between the one end of the primary winding LP 1 and the drain of the transistor M 15 to regulate the current flow in the direction from the primary winding LP 1 to the transistor M 11 . Similarly, the diode D 16 is interposed between the other end of the primary winding LP 1 and the drain of the transistor M 16 to regulate the current flow in the direction from the primary winding LP 1 to the transistor M 16 . Further, the transmission circuit 10 of the present embodiment is also configured with the same type of elements in the same way as the first embodiment described above. In such the case, for example, the transistors M 11 , M 15 , M 13 and M 16 may be the N-type MOSFETs.

The driving part 100 switches ON/OFF of each of the transistors M 11 to M 16 at predetermined timings, and thereby, controlling the kinds and directions of the voltages (primary voltage) applied to the primary winding LP 1 . The control of this driving part 100 will be described as reference to FIG. 5B and FIG. 5C . FIG. 5B is a schematic view illustrating relationships between pulses to each of the transistors M 11 to M 16 and output waveforms from the secondary wingding LS 1 . T 20 , T 21 , T 22 , T 23 and T 24 in FIG. 5B show each of the timings during a period for transmitting the ultrasound waves, and the voltages (secondary voltage) induced in the secondary winding LS 1 are switched for each of the timings. Further, VP 111 , VP 131 , VP 151 , and VP 161 in FIG. 5B show the secondary voltages induced in the secondary side of the transformer K 3 (that is, secondary winding LS 1 ) by the switching of the transistors M 11 to M 16 . The voltage VP 111 in FIG. 5B corresponds to the power source VP 11 , and the voltage VP 131 corresponds to the power source VP 13 . Further, the voltage VP 151 corresponds to the power source VP 15 , and the voltage VP 161 corresponds to the power source VP 16 . In addition, FIG. 5C is a diagram illustrating each of ON/OFF states of the transistors M 11 to M 16 at the timings T 20 , T 21 , T 22 , T 23 and T 24 shown in FIG. 5B . In FIG. 5C , the part shown by “◯” indicates the “ON” state.

As shown in FIG. 5B , at timing T 21 , the driving part 100 supplies pulses to the transistors M 11 , M 12 , M 13 and M 16 . Thereby, as shown in FIG. 5C , the transistors M 11 and M 12 become ON, and the transistors M 13 to M 16 become OFF. The equivalent circuit in this case is shown in FIG. 6A . As shown in FIG. 6A , the primary voltage of the power supply VP 11 is applied to the primary winding. Thereby, as shown in FIG. 5B , the secondary voltage of the VP 111 (positive electrode) is induced in the secondary winding LS 1 , and the induced voltage is applied to the ultrasound transducer C 10 .

Further, as shown in FIG. 5B , at the timing T 22 , the driving part 100 supplies pulses to the transistors M 12 , M 13 , M 15 and M 16 . Thereby, as shown in FIG. 5C , the transistors M 12 and M 15 are ON, and the transistors M 11 , M 13 , M 14 , and M 16 are OFF. The equivalent circuit in this case is shown in FIG. 6B . As shown in FIG. 6B , at the timing T 22 , the primary voltage of the power supply VP 15 is applied to the primary winding LP 1 . Thereby, as shown in FIG. 5B , the secondary voltage of the VP 151 (positive electrode) is induced in the secondary winding LS 1 , and the induced voltage is applied to the ultrasound transducer C 10 .

Further, as shown in FIG. 5B , at the timing T 23 , the driving part 100 supplies pulses to the transistors M 11 , and M 14 to M 16 . Thereby, as shown in FIG. 5C , the transistors M 14 and M 16 become ON, and the transistors M 11 to M 13 , and M 15 become OFF. The equivalent circuit in this case is shown in FIG. 6C . As shown in FIG. 6C , at the timing T 23 , the primary voltage of the power supply VP 16 is applied to the primary winding LP 1 . At this time, the direction of the current flowing into the primary winding LP 1 is opposite of the cases at the timings T 21 and T 22 shown in FIGS. 6A and 6B . Therefore, as shown in FIG. 5B , the secondary voltage of the VP 161 (negative electrode) is induced in the secondary winding LS 1 , and the induced voltage is applied to the ultrasound transducer C 10 .

Further, as shown in FIG. 5B , at the timing T 24 , the driving part 100 supplies pulses to the transistors M 11 , and M 13 to M 15 . Thereby, as shown in FIG. 5C , the transistors M 13 and M 14 become ON, and the transistors M 11 , M 12 , M 15 and M 16 become OFF. The equivalent circuit in this case is shown in FIG. 6D . As shown in FIG. 6D , at the timing T 24 , the primary voltage of the power supply VP 13 is applied to the primary winding LP 1 . At this time, the direction of the current flowing into the primary winding LP 1 is opposite of the cases at the timings T 21 and T 22 shown in FIGS. 6A and 6B . Therefore, as shown in FIG. 5B , the secondary voltage of the VP 131 (negative electrode) is induced in the secondary winding LS 1 , and the induced voltage is applied to the ultrasound transducer C 10 .

Furthermore, as shown in FIG. 5B , at the timing T 20 , the driving part 100 supplies pulses to the transistors M 11 to M 16 . Thereby, as shown in FIG. 5C , the transistors M 12 and M 14 become ON, and the transistors M 11 , M 13 , M 15 and M 16 become OFF. The equivalent circuit in this case is shown in FIG. 6E . As shown in FIG. 6E , at the timing T 20 , the both ends of the primary winding LP 1 are connected to the common voltage. That is, the voltage difference between the both ends of the primary winding LP 1 becomes 0, and the generation of the counter electromotive voltage in the primary winding LP 1 is suppressed. Thereby, as shown in FIG. 5B , the voltage of the secondary winding LS 1 , that is, the voltage to the ultrasound transducer C 10 becomes 0.

As described above, in the ultrasound diagnosis apparatus according to the present embodiment, one circuit group and other circuit group, which have the same configuration and different voltages of the connected power supplies, are connected in parallel to the primary winding LP 1 . Specifically, the one circuit group is a circuit group comprising the power supplies VP 11 and VP 13 , and the transistors M 11 and M 13 . The other circuit group is a circuit group comprising the power supplies VP 15 and VP 16 , and the transistors M 15 and M 16 . In such the configuration, interaction effects which are the same as the ultrasound diagnosis apparatus according to the first embodiment can be obtained, and further, the voltage of a plurality of different levels (more than three) can be applied to the ultrasound transducer C 10 while appropriately switching the voltage.

In the case that pulses having symmetric positive/negative amplitude are output from the secondary winding, the power sources VP 11 and VP 13 may be configured with the same power source VP 0 , and similarly, the power sources VP 15 and VP 16 may be configured with the same power source VP 1 . The circuit diagram of the transmission circuit 10 showing such the example is shown in FIG. 7 . In such the configuration, the voltages VP 111 , VP 131 , VP 151 , and VP 161 shown in FIG. 5B satisfy the following relationships VP 111 =VP 131 =VP 0 , and VP 151 =VP 161 =VP 1 . That is, the pulses output from a secondary winding LS 1 (induced voltages) at the timings T 22 and T 23 become symmetric based on 0. Similarly, the pulses output from the secondary winding LS 1 at the timings T 21 and T 24 become symmetric based on 0.

Further, in the above example, the pulses having different levels are induced in the secondary winding LS 1 by adjusting the voltages of the power sources VP 11 , VP 13 , VP 15 , and VP 16 , however, it may be configured such that the pulses having different levels are output by adjusting the number of the primary winding connected to the transformer K 3 . A circuit diagram of the transmission circuit 10 showing such the example is shown in FIG. 8 . In FIG. 8 , primary windings LP 11 and LP 12 are arranged on the primary side of the transformer K 3 so that those windings are connected in parallel to the secondary winding LS 1 . A circuit group comprising the power source VP 11 , the transistor M 11 , and the diode D 11 is connected to one end of the primary winding LP 11 , and a circuit group comprising the power source VP 13 , the transistor M 13 , and the diode D 13 is connected to the other end thereof. Also, the both ends of the primary winding LP 11 are connected to the common voltage, via the transistors M 12 and M 14 , respectively.

Similarly, a circuit group comprising the power source VP 15 , the transistor M 15 , and the diode D 15 is connected to one end of the primary winding LP 12 , and a circuit group comprising the power source VP 16 , the transistor M 16 , and the diode D 16 is connected to the other end thereof. Also, the both ends of the primary winding LP 12 are connected to the common voltage, via transistors M 12 ′ and M 14 ′, respectively.

In such the configuration, it is possible to adjust the voltage induced in the secondary winding LS 1 by adjusting the voltages of the power sources VP 11 , VP 13 , VP 15 , and VP 16 , and the number of the primary windings LP 11 and LP 12 .

Further, according to the ultrasound diagnosis apparatus of the present embodiment, as shown in FIG. 9A , it is possible to change the voltage to be applied to the ultrasound transducer C 10 . FIG. 9A is schematic diagram illustrating an example of relationships between pulses to each of the transistors M 11 to M 16 and output waveforms from the secondary winding LS 1 . T 31 , T 32 , T 33 , T 34 , and T 35 in FIG. 9A show each of the timings during a period for transmitting the ultrasound waves, and the voltage (secondary voltage) induced from the secondary winding LS 1 is switched at each of the timings. VP 111 , VP 131 , VP 151 , and VP 161 in FIG. 9A correspond to VP 111 , VP 131 , VP 151 , and VP 161 in FIG. 5B , respectively. In addition, FIG. 9B illustrates an ON/OFF state of each of the transistors M 11 to M 16 at the timings T 31 , T 32 , T 33 , T 34 , and T 35 shown in FIG. 9A . In FIG. 9B , the part shown by “◯” indicates the “ON” state.

As shown in FIG. 9A , at the timing T 31 , the driving part 100 supplies pulses to the transistors M 12 , M 13 , M 15 , and M 16 . Thereby, as shown in FIG. 9B , the transistors M 12 and M 15 become ON, and transistors M 11 , M 13 , M 14 , and M 16 become OFF. That is, at the timing T 31 , the primary voltage of the power source VP 15 is applied to the primary winding LP 1 . Thereby, as shown in FIG. 9A , the secondary voltage of the VP 151 (positive electrode) is induced in the secondary winding LS 1 , and the induced voltage is applied to the ultrasound transducer C 10 .

Further, as shown in FIG. 9A , at the timing T 32 , the driving part 100 supplies pulses to the transistors M 11 , M 12 , M 13 , and M 16 . Thereby, as shown in FIG. 9B , the transistors M 11 and M 12 become ON, and transistors M 13 to M 16 become OFF. That is, at the timing T 32 , the primary voltage of the power source VP 11 is applied to the primary winding. Thereby, as shown in FIG. 5B , the secondary voltage of the VP 111 (positive electrode) is induced in the secondary winding LS 1 , and the induced voltage is applied to the ultrasound transducer C 10 .

Further, as shown in FIG. 9A , at the timing T 33 , the driving part 100 supplies pulses to the transistors M 11 to M 16 . Thereby, as shown FIG. 9B , the transistors M 12 and M 14 become ON, and the transistors M 11 , M 13 , M 15 , and M 16 become OFF. That is, at the timing T 33 , the both ends of the primary winding LP 1 are connected to the common voltage. That is, the potential difference between the both ends of the primary winding LP 1 becomes 0, and the generation of the counter electromotive voltage in the primary winding LP 1 is suppressed. Thereby, as shown in FIG. 9A , the voltage of the secondary winding LS 1 , that is, the voltage to the ultrasound transducer C 10 becomes 0.

Further, as shown in FIG. 9A , at the timing T 34 , the driving part 100 supplies pulses to the transistors M 11 , and M 14 to M 16 . Thereby, as shown in FIG. 9B , the transistors M 14 and M 16 become ON, and the transistors M 11 to M 13 , and M 15 become OFF. That is, at the timing T 34 , the primary voltage of the power source VP 16 is applied to the primary winding LP 1 . At this time, the direction of the current flowing into the primary winding LP 1 is opposite of the cases at the timings T 31 and T 32 . Therefore, as shown in FIG. 9A , the secondary voltage of the VP 161 (negative electrode) is induced in the secondary winding LS 1 , and the induced voltage is applied to the ultrasound transducer C 10 .

Furthermore, as shown in FIG. 9A , at the timing T 35 , the driving part 100 supplies pulses to the transistors M 11 , and M 13 to M 15 . Thereby, as shown in FIG. 9B , the transistors M 13 and M 14 become ON, and the transistors M 11 , M 12 , M 15 , and M 16 become OFF. That is, at the timing T 35 , the primary voltage of the power source VP 13 is applied to the primary winding LP 1 . At this time, the direction of the current flowing into the primary winding LP 1 is opposite of the cases at the timings T 31 and T 32 . Therefore, as shown in FIG. 9A , the secondary voltage of the VP 131 (negative electrode) is induced in the secondary winding LS 1 , and the induced voltage is applied to the ultrasound transducer C 10 .

Here, refer to FIG. 11B . FIG. 11B illustrates a circuit diagram a totem pole type transmission circuit used for the conventional ultrasound diagnosis apparatus. As shown in FIG. 11B , this transmission circuit comprises the power sources VP 11 and VP 15 , negative power sources VN 13 , and VN 16 , and the transistors M 11 , M 13 , M 15 , and M 16 . The transmission circuit is connected to the transducer C 10 and a receiving circuit (specifically, the amplifier circuit 12 ), via a diode switch comprising the diodes D 21 and D 22 .

In the example of FIG. 11B , the power sources VP 11 and the VP 15 are connected to the drains of the transistors M 11 and M 15 , respectively. Similarly, the negative power sources VN 13 and VN 16 are connected to the drains of the transistors M 13 and M 16 , respectively. The sources for each of the transistors M 11 , M 13 , M 15 , and M 16 are connected to the ultrasound transducer C 10 and the receiving circuit (specifically, the amplifier circuit 12 ), via the diode switch. The diodes D 11 , D 13 , D 15 , and D 16 are interposed between the diode switch and the transistors M 11 , M 13 , M 15 , and M 16 , respectively, to regulate the current flow.

In such the configuration, the transmission circuit shown in FIG. 11B applies the voltage, based on any one of the following the power sources among the power source VP 11 , the power source VP 15 , the negative power source VN 13 , and the negative power source VN 16 , to the ultrasound transducer C 10 , by turning any of the transistors M 11 , M 13 , M 15 , and 16 ON. That is, the level and the polarity of the voltage to be applied to the ultrasound transducer C 10 is switched by controlling the transistors M 11 , M 13 , M 15 , and M 16 .

However, as shown by the timings from T 31 to T 32 in FIG. 9A , when a different level of the voltage having the same polarity is output, in the conventional transmission circuit shown in FIG. 11B , it is necessary to suck (charge) the charge from the output line indicated with P 31 , in order to lower the voltage from VP 115 to VP 111 . However, since the conventional transmission circuit has no configuration for sucking this charge, so that it is difficult to change the voltage from VP 115 to VP 111 without delay. On the other hand, in the conventional transmission circuit shown in FIG. 11B , when the suction of this charge is to be realized, for example, in the case of the timing from T 31 to T 32 , it requires for the power source VP 15 to use such a power source which is capable of performing both suction and discharge. In the power source in general, however, a positive power source discharges, and a negative power source sucks (charges). It therefore requires a special power source in order to be capable of performing both suction and discharge, and it will be large restrictions regarding to the costs, the circuit size, and the performance thereof.

On the contrary, according to the transmission circuit of the present embodiment shown in FIG. 5A , when the timing is changed from T 31 to T 32 , suction (charge) is performed to the common voltage via the transistor M 12 . For that reason, it is possible to instantly change the voltage, without using any special power supply which is capable of performing both suction (charge) and discharge.

As described above, in the ultrasound diagnosis apparatus according to the present embodiment, one circuit group and other circuit group which have the same configurations and different voltages of the connected power supplies are connected in parallel to the primary winding LP 1 . Specifically, in FIG. 5A , it is shown a circuit group comprising the power supplies VP 11 and VP 13 , and the transistors M 11 , and M 13 . Also, it is shown another circuit group comprising the power supplies VP 15 and VP 16 , and the transistors M 15 , and M 16 . In such the configuration, interaction effects which are the same as the ultrasound diagnosis apparatus according to the first embodiment can be obtained, and further, the voltage of a plurality of different levels (more than five including the case of 0 levels) can be applied to the ultrasound transducer C 10 while appropriately switching the voltage.

Modified Example

Next, a modified example of the ultrasound diagnosis apparatus according to the second embodiment will be described with reference to FIG. 10 . FIG. 10 is an example of a circuit diagram of the transmission circuit 10 in the ultrasound diagnosis apparatus according to the modified example.

In the example shown in the second embodiment (see FIG. 5A ), it is configured such that the transistor M 11 , M 13 , M 15 , and M 16 are the P-type MOSFETs, and the transistors M 12 , and M 14 are the N-type MOSFETs. In such the configuration, it is necessarily that the number of the transistors (the P-type MOSFETs) to be connected to the power source (that is, VP 11 , VP 13 , VP 15 , and VP 16 ) exceeds the number of the transistors (the N-type MOSFETs) to be connected to the common voltage. It is, however, not limited to this configuration if it is possible to change the kind and direction of the voltage for the primary winding LP 1 . For example, in the modified example, as shown in FIG. 10 , the transmission circuit 10 is configured such that the N-type MOSFET is connected to the power source side, and the P-type MOSFET is connected to the common voltage side. Specifically, in the transmission circuit 10 , the circuit connected to the primary winding LP 1 of the transformer K 3 comprises the negative power source VN 11 , VN 13 , VN 15 , and VN 16 , transistors M 11 ′ to M 16 ′, and the diodes D 11 , D 13 ,D 15 , and D 16 .

The source of the transistor M 11 ′ is connected to the negative power source VN 11 , and the source of the transistor M 13 ′ is connected the negative power source VN 13 . Similarly, the source of the transistor M 15 ′ is connected to the negative power source VN 15 , and the source of the transistor M 16 ′ is connected the negative power source VN 16 . Also, the sources of the transistors M 12 ′ and M 14 ′ are connected to the common voltage, respectively.

One end of the primary winding LP 1 is connected to the drain of the transistor M 11 ′, the drain of the transistor M 15 ′, and the drain of the transistor M 14 ′. The diode D 11 is interposed between the one end of the primary winding LP 1 and the drain of the transistor M 11 ′, to regulate the current flow in the direction from the transistor M 11 ′ to the primary winding LP 1 . Similarly, the diode D 15 is interposed between the one end of the primary winding LP 1 and the drain of the transistor M 15 ′, to regulate the current flow in the direction from the transistor M 15 ′ to the primary winding LP 1 .

Further, the other end of the primary winding LP 1 is connected to the drain of the transistor M 13 ′, the drain of the transistor M 16 ′, and the drain of the transistor M 12 ′. The diode D 13 is interposed between the other end of the primary winding LP 1 and the drain of the transistor M 13 ′, to regulate the current flow in the direction from the transistor M 13 ′ to the primary winding LP 1 . Similarly, the diode D 16 is interposed between the other end of the primary winding LP 1 and the drain of the transistor M 16 ′, to regulate the current flow in the direction from the transistor M 16 ′ to the primary winding LP 1 .

The ON/OFF switching for each of the transistors M 11 ′ to M 16 ′ is performed by the driving part 100 in the same way as in the second embodiment. Specifically, by causing the transistors M 11 ′ and M 12 ′ to be ON, and the transistors M 13 ′ to M 16 ′ be OFF, the primary voltage of the negative power source VN 11 is applied to the primary winding LP 1 . Similarly, by causing the transistors M 15 ′ and M 12 ′ to be ON, and the transistors M 11 ′, M 13 ′, M 14 ′, and M 16 ′ be OFF, the primary voltage of the negative power source VN 13 is applied to the primary winding LP 1 .

Further, by causing the transistors M 13 ′ and M 14 ′ to be ON, and the transistors M 11 ′, M 12 ′, M 15 ′, and M 16 ′ be OFF, the primary voltage of the negative power source VN 13 is applied to the primary winding LP 1 . At this time, the primary voltage of the negative power source VN 13 is applied to the primary winding LP 1 in the opposite direction of the case when the voltage of the negative power source VN 11 is applied. Similarly, by causing the transistors M 16 ′ and M 14 ′ to be ON, and the transistors M 11 ′ to M 13 ′, and M 15 ′ be OFF, the primary voltage of the negative power source VN 16 is applied to the primary winding LP 1 . At this time, the primary voltage of the negative power source VN 16 is applied to the primary winding LP 1 in the opposite direction of the case when the primary voltage of the negative power source VN 15 is applied.

Therefore, by causing the transistors M 12 ′ and M 14 ′ to be ON, and the transistors M 11 ′, M 13 ′, M 15 ′ and M 16 ′ be OFF, the both ends of the primary winding LP 1 are connected to the common voltage. Thereby, the potential difference between the both ends of the primary winding LP 1 becomes 0, and the generation of the counter electromotive voltage in the primary winding LP 1 is suppressed. That is, the voltage of the secondary winding LS 1 , that is, the voltage to the ultrasound transducer C 10 becomes 0.

As described above, as shown in FIG. 10 , the ultrasound diagnosis apparatus according the modified example configures the transmission circuit 10 by connecting the N-type MOSFET to the power source side and the P-type MOSFET to the common voltage side. That is, the number of the P-type MOSFET and the number of the N-type MOSFET required to configure the transmission circuit 10 are reversed of the case of the ultrasound diagnosis apparatus according to the second embodiment (the number of the P-type MOSFET<the numbers of the N-type MOSFET). Thereby, according to each of the trading volumes of the P-type MOSFET and the N-type MOSFET, the configuration according to the second embodiment (see FIG. 5A ), and the configuration according to the modified example can be appropriately selected, and it is possible to reduce the production costs of the transmission circuit 10 .

10 Transmission circuit

K 3 Transformer

LP 1 , LP 11 , LP 12 Primary winding

LS 1 Secondary winding

VP 11 , VP 13 , VP 15 , VP 16 Power source

VN 11 , VN 13 , VN 15 , VN 16 Negative power source

D 11 , D 13 , D 15 , D 16 Diode

M 11 , M 11 ′ Transistor

M 12 , M 12 ′ Transistor

M 13 , M 13 ′ Transistor

M 14 , M 14 ′ Transistor

M 15 , M 15 ′ Transistor

M 16 , M 16 ′ Transistor

11 Ultrasound diagnosis transducer group

C 10 Ultrasound transducer

12 Amplifier circuit

13 Delay circuit

14 Adding circuit

15 Signal processor

16 Image processor

17 Display

100 Driving part