JP6951191B2 - Voltage supply circuit and ultrasonic diagnostic equipment - Google Patents

Description

The present invention relates to a voltage supply circuit, and more particularly to a voltage supply circuit capable of selectively outputting voltages of different levels (amplitude). The present invention also relates to an ultrasonic diagnostic apparatus that uses the voltage from the voltage supply circuit to drive the vibrator.

In the ultrasonic diagnostic apparatus, the vibrator provided in the probe is driven to transmit ultrasonic waves, but a high voltage is required to drive the vibrator. Further, it is known that the vibrator is driven by a bipolar pulse (bipolar pulse) in order to widen the ultrasonic wave generated by the vibrator (Patent Document 1).

A positive voltage and a negative voltage are required to generate a bipolar pulse. Also, different levels of positive and negative voltages are required to vary the amplitude of the bipolar pulse in order to vary the power of the ultrasonic waves.

As a circuit capable of generating different multiple levels of voltage in a space-saving manner, a circuit is known in which a switch and a capacitor are connected in multiple stages to generate a voltage that is an integral multiple of the input voltage for each output stage (Patent Document 2). ..

Japanese Unexamined Patent Publication No. 2011-50471 Japanese Unexamined Patent Publication No. 2001-309641

When a circuit having a multi-stage configuration as described in Patent Document 2 is used, a switch for selecting one of a plurality of levels of voltage that can be output is required. A relay is commonly used as such a switch. However, since the relay has a large component height, when it is mounted on the substrate, it is necessary to secure a distance between the substrate and the inner surface of the housing by a spacer or the like so that the relay does not interfere with the housing of the device. Therefore, the relay may not be used when there is not enough space in the housing, such as when the device is small.

Further, although a semiconductor switch having a small height dimension may be used as a switch for outputting a positive voltage, there has been no small semiconductor switch for outputting a negative voltage.

The present invention has been made in view of such problems of the prior art, and a main object thereof is to provide a voltage supply circuit capable of supplying a plurality of levels of negative voltage, which is easy to miniaturize and switch control. be.

The above-mentioned purpose is to provide a first voltage generation circuit capable of outputting negative voltages having different levels, and a plurality of first selection switches for selecting the level of the negative voltage output from the first voltage generation circuit. It is achieved by a voltage supply circuit having a voltage supply circuit, wherein the first selection switch is a semiconductor switch that can be turned on and off using a positive voltage.

With such a configuration, according to the present invention, it is possible to provide a voltage supply circuit capable of supplying a plurality of levels of negative voltage and facilitating miniaturization and switch control.

It is a schematic circuit diagram of the voltage supply circuit which concerns on embodiment of this invention. It is a schematic circuit diagram of the selection switch in an embodiment. It is a schematic circuit diagram of another voltage supply circuit which concerns on embodiment of this invention. It is a schematic functional block diagram of the ultrasonic diagnostic apparatus using the voltage supply circuit which concerns on embodiment of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings based on an exemplary embodiment.
FIG. 1 is a schematic circuit diagram of the voltage supply circuit 100 according to the present embodiment. The voltage supply circuit 100 includes a voltage generation circuit 110 and a selection switch circuit 120. The voltage generation circuit 110 switches a capacitor to generate a multi-level voltage of -1 to −n times (n is an integer of 2 or more, here n = 5) of the power supply voltage VIN (> 0) of the power supply PW. It is a multi-stage charge pump circuit to be generated.

By inputting a pulse signal having two levels of ground potential (0V) and power supply voltage VIN to the inverter INV from the outside, the charging period of the capacitor by the power supply voltage VIN and the charging period and the output period of reversing the polarity of the capacitor can be set. Repeated. The charge pump circuit is not limited to a configuration that uses capacitor switching (polarity reversal) using an inverter, and any known circuit configuration such as a configuration that switches the capacitor connection path using a switch may be used. ..

The voltage generation circuit 110 has a multi-stage configuration, and the type of voltage level that can be generated can be changed by increasing or decreasing the number of stages of the unit circuit to be connected. As the number of stages is increased, a voltage having a large level (amplitude) (a voltage having a large absolute value) can be generated.

A plurality of diodes connected in series to points O1 to O5 are provided to prevent backflow of charge during the output period. In the output period, when viewed from points O1 to O5 of the voltage generation circuit 110, different numbers of capacitors charged to -VIN during the charging period are connected to the inverter INV, and points O1 to O5 are connected. The potential is −VIN to −5VIN.

Therefore, by selectively connecting one of the points O1 to O5 to the output line, a voltage at a level corresponding to the connected point can be supplied from the output line. In the present embodiment, the point O1 at which −VIN is obtained is not used and is not connected to the selection switch circuit 120, but the point O1 may be configured to be selectable by the selection switch circuit 120.

The selection switch circuit 120 is a circuit for selectively connecting one of the points O2 to O5 of the voltage generation circuit 110 to the output line, and is provided with a one-to-one correspondence with the points O2 to O5. It has switches SW1 to SW4. The selection switches SW1 to SW4 have the same configuration using MOS-FETs, and on and off can be controlled by the voltage of the control signal.

In the present embodiment, the selection switch for selecting the level of the negative voltage to be output is realized as a semiconductor switch using FET. Therefore, it is possible to control the on / off of the selection switch by voltage, and it is advantageous in terms of height dimension at the time of mounting. Furthermore, since it is configured so that a positive voltage of logic level (3.3 to 5 V) can be used as a control signal used for on / off control, a special power supply or voltage conversion circuit is not required when it is incorporated into a device and used. be.

Specifically, FIG. 2A shows one of the selection switches SW1 to SW4 included in the switch circuit 120 extracted. The selection switch is configured by using one Pch MOS-FET (hereinafter referred to as P-FET) and one Nch MOS-FET (hereinafter referred to as N-FET).

The gate of the P-FET 121P is grounded, and a control signal is input to the source. Further, the N-FET 121N has an input (one of points O2 to O5) connected to the source and a drain connected to the output line. Further, the drain of the P-FET 121P and the gate of the N-FET 121N are connected. The resistors 122 and 123 divide the potential between the source of the N-FET 121N and the drain of the P-FET 121P to generate the gate potential of the N-FET 121N.

The P-FET 121P is turned on when the control signal input to the source, which can take a logical low and a high level, is at a high level. Since the potentials of the points O2 to O5 to which the source of the N-FET 121N is connected are different in the selection switches SW1 to SW4, the resistors 122, so that the N-FET 121N is turned on in response to the connection of the connected P-FET 121P being turned on. Each value of 123 is determined.

FIG. 3 is a schematic circuit diagram of a voltage supply circuit 200 that can be suitably used together with the voltage supply circuit 100. The voltage supply circuit 200 includes a voltage generation circuit 210 and a selection switch circuit 220. The voltage generation circuit 210 has a multi-stage configuration in which a capacitor is switched to generate a voltage of 2 to n times (n is an integer of 3 or more, here n = 5) of the power supply voltage VIN (> 0) of the power supply PW. It is a charge pump circuit.

By inputting a pulse signal having two levels of ground potential (0V) and power supply voltage VIN to the inverter INV from the outside, the charging period of the capacitor by the power supply voltage VIN and the charging period and the output period of reversing the polarity of the capacitor can be set. Repeated. The charge pump circuit is not limited to a configuration that uses capacitor switching (polarity reversal) using an inverter, and any known circuit configuration such as a configuration that switches the capacitor connection path using a switch may be used. ..

The voltage generation circuit 210 has a multi-stage configuration, and the type of voltage level that can be generated can be changed by increasing or decreasing the number of stages of the unit circuit to be connected. As the number of stages is increased, a voltage having a large level (amplitude) (a voltage having a large absolute value) can be generated.

A plurality of diodes connected in series to points O2 to O5 are provided to prevent backflow of charge during the output period. In the output period, when viewed from points O2 to O5 of the voltage generation circuit 210, different numbers of capacitors charged in the VIN during the charging period are connected to the inverter INV, and the potential of points O2 to O5 is reached. Is 2VIN to 5VIN.

Therefore, by selectively connecting one of the points O2 to O5 to the output line, a voltage at a level corresponding to the connected point can be supplied from the output line. In the present embodiment, since VIN is not used as it is as an output, a selection switch for outputting VIN as it is is not provided, but the VIN may be configured so that it can be selected by the selection switch circuit 220.

The selection switch circuit 220 is a circuit for selectively connecting one of the points O2 to O5 of the voltage generation circuit 210 to the output line, and is provided with a one-to-one correspondence with the points O2 to O5. It has switches SW1 to SW4. The selection switches SW1 to SW4 have the same configuration using MOS-FETs, and on and off can be controlled by the voltage of the control signal.

In the present embodiment, similarly to the voltage supply circuit 100 that supplies a negative voltage, a selection switch for selecting the level of the positive voltage to be output is realized as a semiconductor switch using an FET. Therefore, it is possible to control the on / off of the selection switch by voltage, and it is advantageous in terms of height dimension at the time of mounting. Further, since the same control signal as the voltage supply circuit 100 can be used, the absolute value of the output potential in the voltage supply circuits 100 and 200 is generated when the bipolar pulse in which the positive voltage and the negative voltage have the same absolute value is generated. A pair of selection switches with the same equality can be turned on and off using the same control signal.

FIG. 2B shows one of the selection switches SW1 to SW4 included in the switch circuit 220 extracted. The selection switch is configured by using one Pch MOS-FET (hereinafter referred to as P-FET) and one Nch MOS-FET (hereinafter referred to as N-FET).

The source of the N-FET 221N is grounded, and a control signal is input to the gate. Further, the P-FET 221P has an input (one of points O2 to O5) connected to the source and a drain connected to the output line. Further, the drain of the N-FET 221N and the gate of the P-FET 221P are connected. The resistors 222 and 223 divide the potential between the source of the P-FET 221P and the drain of the N-FET 221N to generate the gate potential of the P-FET 221P.

The N-FET 221N is turned on when the control signal input to the gate, which can take a logical low and a high level, is at a high level. Since the potentials of the points O2 to O5 to which the source of the P-FET 221P is connected are different in the selection switches SW1 to SW4, the resistors 222, so that the P-FET 221P is turned on according to the ON of the connected N-FET 221N. Each value of 223 is determined.

As described above, according to the present embodiment, the selection switches SW1 to SW4 (FIG. 2 (a)) for negative voltage and the selection switches SW1 to SW4 (FIG. 2 (b)) for positive voltage are used as P-FET and N. It can be realized by a circuit configuration in which the −FET is replaced.

FIG. 4 is a functional block diagram schematically showing an ultrasonic diagnostic apparatus using the voltage supply circuits 100 and 200 described with reference to FIGS. 1 to 3. The ultrasonic diagnostic apparatus in FIG. 4 is described by paying attention to a configuration in which voltage supply circuits 100 and 200 are used to generate bipolar pulses for driving the vibrator included in the probe, and is described for general ultrasonic diagnosis. Some of the configurations of the device are omitted.

The control unit 300 has a programmable processor such as a CPU, a ROM, and a RAM, and controls each part of the ultrasonic diagnostic apparatus by reading the program stored in the ROM into the RAM and executing the program, and functions of the apparatus. To realize. The control unit 300 controls the operations of the control signal generation circuit 310 and the switching circuit 330 in response to a user instruction through an operation unit 360 such as a console, and changes the voltage level and pulse width of the bipolar pulse.

The control signal generation circuit 310 outputs a control signal for turning on one of the selection switches SW1 to SW4 in each of the selection switch circuits 120 and 220 of the voltage supply circuits 100 and 200 according to the control of the control unit 300. And 200 are supplied.

The clock generation circuit 320 generates a clock pulse in which the power supply level and the ground level are repeated in a predetermined cycle, and supplies the clock pulse to the inverter INVs of the voltage supply circuits 100 and 200.
The switching circuit 330 alternately selects and outputs a negative voltage output by the voltage supply circuit 100 and a positive voltage output by the voltage supply circuit 200 at a timing according to the control of the control unit 300 to output a bipolar pulse. Generate and supply to the transducer 400.

The vibrator 400 transmits an ultrasonic pulse, converts the received echo into an electric signal, and outputs the echo to the signal processing circuit 340. Although only the driving of one oscillator is described here for convenience, as is well known in the art, it is possible to drive a plurality of oscillators at various timings.

The signal processing circuit 340 executes processing according to the measurement mode on the received electric signal, and generates, for example, an image to be displayed on the display unit 350 which is an LCD. Then, the generated image is displayed on the display unit 350.

As described above, by using the voltage supply circuits 100 and 200 according to the present embodiment, a plurality of types of bipolar pulses having different levels (magnitude of amplitude) can be easily generated, for example, driving an oscillator in an ultrasonic diagnostic apparatus. Can be suitably used for.

The voltage supply circuit according to the present embodiment can be applied to any electronic device that dynamically uses different levels of voltage for at least negative voltage. For medical devices, defibrillators and the like that use a biphasic waveform can be exemplified.

100, 200 ... Voltage supply circuit, 110, 210 ... Voltage generation circuit, 120, 220 ... Selection switch circuit

Claims (8)

A first voltage generation circuit that can output negative voltages of different levels,
A plurality of first selection switches for selecting the level of the negative voltage output from the first voltage generation circuit, and
Is a voltage supply circuit with
A voltage supply circuit, wherein the first selection switch is a semiconductor switch that can be turned on and off using a positive voltage. The first voltage generation circuit is a multi-stage charge pump circuit having a plurality of output stages that output negative voltages of different levels from each other, and each of the plurality of first selection switches is one of the plurality of output stages. The voltage supply circuit according to claim 1, wherein one output is selected. Each of the first selection switches is composed of a combination of an Nch MOS-FET and a Pch MOS-FET, and among the plurality of the first selection switches, a control signal input to the source of the Pch MOS-FET is The voltage supply circuit according to claim 1 or 2, wherein a negative voltage corresponding to a logical high-level switch is selected. Each of the first selection switches is composed of a combination of Nch MOS-FET and Pch MOS-FET.
In the Pch MOS-FET, the gate is grounded, the control signal of the switch is input to the source, and the drain is connected to the Nch MOS-FET.
In the Nch MOS-FET, a one-level negative voltage that can be output by the first voltage generation circuit is input to the source, the source and the gate are connected, and the control signal is sent to the source when the control signal is at a logical high level. Output the input negative voltage from the drain,
The voltage supply circuit according to any one of claims 1 to 3, wherein the voltage supply circuit is characterized. A second voltage generation circuit that can output positive voltages of different levels,
A plurality of second selection switches for selecting the level of the positive voltage output from the second voltage generation circuit, and
A switching means for switching and outputting a negative voltage selected by the first selection switch and a positive voltage selected by the second selection switch.
The voltage supply circuit according to any one of claims 1 to 4, further comprising. Each of the second selection switches is configured by a combination of an Nch MOS-FET and a Pch MOS-FET, and among the plurality of the second selection switches, a control signal input to the gate of the Nch MOS-FET is The voltage supply circuit according to claim 5, wherein a positive voltage corresponding to a logical high-level second selection switch is selected. The voltage supply circuit according to claim 5 or 6,
An oscillator driven by the voltage output by the switching means of the voltage supply circuit, and
A generation means for generating an image based on the signal detected by the vibrator, and
An ultrasonic diagnostic apparatus characterized by having. The voltage supply circuit according to claim 5 or 6 is provided.
An electronic device using a voltage output by the switching means of the voltage supply circuit.

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