KR100947829B1 - Apparatus for generating a pulse width modulated transmit pulse in an ultrasound diagnostic system - Google Patents

Abstract

An apparatus for generating a transmission pulse of an ultrasound diagnostic system according to the present invention includes: a control signal generator configured to generate a plurality of control signals by phase-delaying a pulse signal having a predetermined cycle and a duty cycle in a plurality of steps; And a plurality of switches driven in response to the plurality of control signals between one power supply and ground, wherein pulse widths are adjusted by zero voltage switching of the plurality of switches according to the plurality of control signals. And a transmission pulser for generating a transmission pulse signal.

Ultrasonic Diagnostic System, Transmit Pulsor, Duty Cycle, Apodization, Phase Delay

Description

Apparatus for generating a pulse width modulated transmit pulse in an ultrasound diagnostic system}

1 is a circuit diagram showing the configuration of a transmission pulser according to the prior art.

2 is a block diagram schematically showing the configuration of an ultrasound diagnostic system;

3 is a block diagram showing a configuration of a transmission pulse generator.

4 is a block diagram showing a configuration of a control signal generator of a transmit pulse generator according to an exemplary embodiment of the present invention.

5 is a circuit diagram showing a configuration of a transmission pulser according to an embodiment of the present invention.

6 is a timing diagram of a control signal according to an embodiment of the present invention.

7 is a waveform diagram showing a transmission pulse signal generated by a control signal according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

210 probe 220 Tx / Rx switch

230 Transmitter pulse generator 240 Beamformer

250 receive amplifier 260 ADC

270 Image Signal Processing Unit 280 Display Unit

232 Control signal generator 234 Transmit pulser

410 pulse signal generator 420 first variable delay unit

430 second variable delay unit 440 third variable delay unit

The present invention relates to an ultrasonic diagnostic system, and more particularly, to a transmission pulse generating apparatus capable of generating a pulse width modulated transmission pulse signal in an ultrasonic diagnostic system.

The ultrasound diagnostic system transmits the transmission pulse generated by the transmission pulser to the conversion element of the probe, and the conversion element generates an ultrasonic signal in response to the transmission pulse signal. The ultrasound signal generated as described above is transmitted to the object, and an echo signal thereof is obtained to obtain an ultrasound image signal of the object. The ultrasound image signal is displayed as an ultrasound image through a display device such as a monitor or a screen after proper signal processing such as scan conversion and rendering.

In general, an ultrasound diagnosis system may acquire an ultrasound image having a higher resolution as the frequency of an ultrasound signal is higher. However, the attenuation of the ultrasonic signal generated when the ultrasonic signal is transmitted through the object limits the depth at which the high frequency ultrasonic signal can penetrate into the object. That is, the frequency of the ultrasound signal is determined by the transmission speed of the ultrasound signal in the object and the resolution of the ultrasound image required for the space to be diagnosed.

For example, the propagation rate and attenuation of ultrasonic signals to organs, blood flow, bones, etc. of the human body are different. Therefore, in order to obtain a desired ultrasound image for the part to be diagnosed, it is necessary to adjust the appropriate frequency. At this time, the frequency of the ultrasonic signal is determined by the transmission pulse signal transmitted to the probe. The transmit pulse signal is generated in a transmit pulser provided for each channel.

1 is a circuit diagram showing the configuration of a transmission pulser 134 according to the prior art.

As shown in FIG. 1, two conventional power supply pulsers are applied, that is, a first power source (+ HV) and a second power source (−HV), and the first power source in response to the first control signal C1. In response to the first switch S1 for switching (+ HV) and the second control signal C2 output from the controller 132, the second switch S2 for switching the second power source (-HV). Consists of. Conventional transmit pulsers use two power sources, requiring a lot of power for the ultrasound diagnostic system.

The present invention is to solve the above-mentioned problems of the prior art, and provides an apparatus for generating a transmission pulse capable of modulating the width of a transmission pulse using a single power supply in an ultrasonic diagnostic system.

In order to achieve the above object, the apparatus for generating a transmission pulse of an ultrasonic diagnostic system according to the present invention generates a plurality of control signals by phase-delaying a pulse signal having a predetermined cycle and a duty cycle in a plurality of stages. A control signal generator; And a plurality of switches driven in response to the plurality of control signals between one power supply and ground, wherein pulse widths are adjusted by zero voltage switching of the plurality of switches according to the plurality of control signals. And a transmission pulser for generating a transmission pulse signal.

Hereinafter, a transmission pulse generating apparatus for generating a transmission pulse signal modulated with a pulse width in the ultrasonic diagnostic system according to the present invention will be described in detail with reference to FIGS. 2 to 6.

2 is a block diagram schematically illustrating a configuration of an ultrasound diagnostic system.

Referring to FIG. 2, the ultrasound diagnosis system 200 includes a probe 210, a Tx / Rx switch 220, a transmission pulse generator 230, a beamformer 240, a reception amplifier 250, and an analog to digital signal. The converter 260 includes an image signal processor 270 and a display 280.

The probe 210 generates an ultrasound signal, transmits the ultrasound signal to the object, receives the ultrasound signal reflected from the object, and converts the ultrasound signal into an electrical signal. The Tx / Rx switch 220 alternately switches the transmit pulse signal and the receive signal. As shown in FIG. 3, the transmission pulse generator 230 includes a control signal generator 232 and a transmission pulser 234, and the transmission pulser 234 is a control signal output from the control signal generator 232. In response, generate a transmit pulse signal. The beamformer 240 forms a transmission beam and a reception beam to obtain a desired ultrasound image.

The amplifier 250 amplifies the received signal received through the Tx / Rx switch, the amplified received signal is converted into a digital received signal from the analog-digital converter 260 is transmitted to the beamformer 240. The beamformer 240 focuses the received digital received signal to form a receive beam. The image signal processing unit 270 processes the reception beam to obtain a Youngsan signal. The display 280 receives an image signal and displays an ultrasound image of the object.

4 is a block diagram illustrating a configuration of a control signal generator of a transmission pulse generator according to an exemplary embodiment of the present invention. The transmission pulse generator generates the first, second, third and fourth control signals S1 (t), S2 (t), S3 (t) and S4 (t). Referring to FIG. 4, the control signal generator 232 includes a pulse signal generator 410, a first variable delay unit 420, a second variable delay unit 430, and a third variable delay unit 440. do. The pulse signal generator 410 generates a pulse signal having a predetermined cycle and a duty cycle as the first control signal S1 (t). Preferably, in one embodiment of the present invention, the pulse signal generator 410 generates a pulse signal having a duty cycle of 50%. The first variable delay unit 420 is composed of a variable delay element capable of adjusting a delay amount, and delays a phase of the first control signal S1 (t) (hereinafter, referred to as a first delay) to control the second control signal S4. (t)) As the variable delay element, a controllable RC delay element or a shift register may be used.

Similar to the first variable delay unit 420, the second variable delay unit 430 is configured as a variable delay element, and the first control signal S1 (t) is provided for a time required for dead time inverting. The third control signal S3 (t) is output by delaying the phase (hereinafter referred to as a second delay). The second delay is set so that the phases of the first control signal S1 (t) and the third control signal S3 (t) do not overlap each other. The third variable delay unit 440 is configured in the same manner as the first variable delay unit 420 and phase-delays the third control signal S3 (t) output from the second variable delay unit 430. The third control signal S2 (t) is outputted. In the embodiment of the present invention, the first delay and the third delay are substantially the same.

5 is a circuit diagram showing the configuration of a transmission pulser 234 according to an embodiment of the present invention. As shown in FIG. 5, the transmission pulser 234 according to the embodiment of the present invention includes first, second, third and fourth switches SW1, SW2, SW3, and SW4, a voltage converter 510, and an output unit ( 520). The first switch SW1 and the third switch SW3 are connected in series between the power supply Vs and the ground. In addition, the second switch SW2 and the fourth switch SW4 are also connected in series between the power supply Vs and the ground, and the first switch SW1 and the third switch SW3 are connected to the second switch SW2. It is connected in parallel with the fourth switch SW4. In the embodiment of the present invention, various switching elements such as a field effect transistor (FET) may be used as the first, second, third, and fourth switches SW1, SW2, SW3, and SW4. The signals S1 (t), S2 (t), S3 (t) and S4 (t) serve to drive the first, second, third and fourth switches SW1, SW2, SW3 and SW4. For example, when the first, second, third, and fourth switches SW1, SW2, SW3, and SW4 are implemented as FETs, the first, second, third, and fourth control signals S1 (t), S2 (t), S3 (t) and S4 (t) are applied to the gate of the field effect transistor (FET), respectively.

The voltage converter 510 is implemented as a transformer, and the first input terminal of the voltage converter 510 is connected to the first node N1 connecting the first switch SW1 and the third switch SW3. The second input terminal of the voltage converter 510 is connected to a second node N2 connecting the second switch SW2 and the fourth switch SW4. The voltage converter 510 converts the power supply voltage Vs and outputs the output voltage to the output unit 520. The output unit 530 finally outputs a transmission pulse signal.

6 is a timing diagram of a control signal according to an embodiment of the present invention.

As shown in FIG. 6, when t1 has a logic level of the first control signal S1 (t) becoming “high” (hereinafter, referred to as “high”), it is shown in FIG. 5. The first switch SW1 is turned on so that the power source Vs is applied to the first node N1 through the first switch SW1. Thereafter, when the first control signal S1 (t) is delayed by the first delay delay Φ in the first variable delay unit 420 and the second control signal S4 (t) becomes “high” at t2, The fourth switch SW4 is turned on to connect the second node N2 to ground. Accordingly, the power Vs applied to the first node is supplied to the second node N2 through the voltage converter 510, and the power Vs supplied to the voltage converter 510 is at a predetermined voltage level. Is converted to and output to the output unit 520.

Subsequently, when the logic level of the first control signal S1 (t) becomes "low" (hereinafter referred to as "low") at t3, the first switch SW1 is turned off to convert the voltage. Supply of power Vs to the unit 510 is stopped. At this time, the fourth switch SW4 is maintained in the on state until the third control signal S3 (t) becomes high and the third switch SW3 is turned on. At this time, the current flows from the fourth switch SW4 to the third switch SW3 through the voltage converter 510. Since the voltage difference between both ends of the third switch SW3 is 0 V when the third switch SW3 is turned on, the third switch SW3 is turned on without stress. That is, zero-voltage switching. After the third switch SW3 is turned on, the second control signal S4 (t) transitions to "low".

When the third control signal S3 (t) output by being delayed by the second variable delay unit 430 by the second delay (time required for the floating time conversion) becomes “high” at t4, the second variable delay unit 430 shown in FIG. The third switch SW3 is turned on to connect the first node N1 to ground. Thereafter, the third control signal S3 (t) is delayed by the third variable delay unit 440 by the first delay Φ, and the fourth control signal S2 (t) output as “high” at t5. When the second switch SW2 is turned on, the power supply Vs is applied to the second node N2. Accordingly, the power Vs applied to the second node N2 is supplied to the first node N1 through the voltage converter 510, and the power Vs supplied to the voltage converter 510 is predetermined. The level is converted and output to the output unit 520.

Subsequently, when the third control signal S3 (t) becomes " low " at t6, the third switch SW3 is turned off to supply the power Vs to the voltage converter 510. It stops. In this case, the second switch SW2 is turned on for a predetermined time so that a current flows from the second switch SW2 through the voltage converter 510 to the first switch SW1. At this time, when the first control signal S1 (t) becomes high at t7 and the first switch SW1 is turned on, the voltage difference between the both ends of the first switch SW1 is 0V. The switch SW1 is on without stress. That is, zero voltage switching is performed. The above-mentioned operation is repeatedly performed to generate a transmission pulse signal.

7 is a waveform diagram illustrating a transmission pulse signal generated by a control signal according to an embodiment of the present invention.

7 illustrates an output when the voltage ratio 510 has a transformer ratio of 1: 1. In the waveform of the transmission pulse signal shown in FIG. 7, the first pulse width W1 and the second pulse width W2 are determined by the first delay and the third delay. For example, increasing the first delay and the third delay decreases the first pulse width W1 and the second pulse width W2 relatively, while decreasing the first delay and the third delay decreases the first pulse width W1. ) And the second pulse width W2 are relatively increased.

The transmission pulse generator according to an embodiment of the present invention may generate a transmission pulse signal having a pulse width adjusted by adjusting a phase of a control signal, and driving the first switch SW1 and the third switch SW3 of the transmission pulser. Zero voltage switching can be performed without stress by setting the voltage difference between the time switches to 0 V, thereby reducing noise such as spikes that can be issued to the transmission pulse signal.

It is to be understood that the above described embodiments are merely illustrative of some of the various embodiments employing the principles of the present invention. It will be apparent to those skilled in the art that various modifications may be made without departing from the spirit of the invention.

As described above, the transmission pulse signal according to the present invention can be generated using a single power source to reduce the number of power sources of the ultrasound diagnostic system, and to control the phase delay of the control signals to generate the transmission pulse signal having various pulse widths. As a result, apodization may be performed at the transducer of the probe of the ultrasound diagnostic system, thereby reducing side lobes. In addition, in apodization, each switch of the transmission pulser drives a control signal having a constant duty cycle at all times by adjusting only a phase delay, thereby generating a high frequency transmission pulse regardless of the frequency characteristic of the switch element.

In addition, zero-voltage switching of the switch of the transmission pulser can reduce noise in the transmission pulse signal.

Claims (7)

In the transmission pulse generator of the ultrasonic diagnostic system, A control signal generator for generating a plurality of control signals by phase-delaying a pulse signal having a predetermined cycle and a duty cycle in a plurality of steps; And And a plurality of switches driven in response to the plurality of control signals between one power supply and ground, wherein pulse widths are adjusted by zero voltage switching of the plurality of switches according to the plurality of control signals. Transmit pulser to generate transmit pulse signal Transmission pulse generation apparatus of the ultrasonic diagnostic system comprising a. The method of claim 1, The control signal generator, A signal generator which generates the pulse signal as a first control signal; A first variable delay unit delaying a phase of the first control signal by a first delay and outputting a second control signal; A second variable delay unit delaying a phase of the first control signal by a second delay and outputting a third control signal; And A third variable delay unit delaying a phase of the upper third control signal by a third delay and outputting a fourth control signal Transmission pulse generation apparatus of the ultrasonic diagnostic system comprising a. The method of claim 2, The transmission pulser, A first switch and a second switch connected in series between the power supply and the ground and respectively switching in response to the first control signal and the second control signal; A third switch and a fourth switch connected in series between the power supply and the ground and connected in parallel with the first switch and the second switch, and respectively switching in response to the third control signal and the fourth control signal; An operation of the first, second, third, and fourth switches connected to a first node between the first switch and the second switch and a second node between the third switch and the fourth switch; A voltage converter configured to convert the voltage of the power by receiving the power; And Output unit for outputting the converted voltage as a pulse signal Transmission pulse generation apparatus of the ultrasonic diagnostic system comprising a. The method of claim 3, wherein And a pulse width of the transmission pulse signal is determined by the first delay. The method of claim 4, wherein The first, second, third and fourth switches are field effect transistors (FETs). The method of claim 5, wherein And transmitting the first, second, third and fourth control signals to the gate of the FET, respectively. The method of claim 6, Wherein the duty cycle of the pulse signal is 50%.

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