JPH0833340A - Ultrasonic diagnostic equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] An EMI noise filter can be inserted without reducing the power factor of the power factor correction rectifier circuit. [Structure] An ultrasonic diagnostic apparatus has a power supply circuit connected to an AC power supply. The power supply circuit includes a first rectifying bridge circuit 11, a filter capacitor C _f , a power factor improving switching element Q ₁ , a second rectifying bridge circuit 12,
And a control circuit 13. The power factor improving switching element Q ₁ shapes the current waveform input from the first rectifying bridge circuit 11, and is controlled by the control circuit 13 based on the voltage waveform input from the second rectifying bridge circuit 12. ing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus having a power supply circuit connected to an AC power source.

[0002]

[Prior art]

(A) The ultrasonic diagnostic apparatus usually includes a power supply circuit connected to an AC power supply. A switching regulator may be used as the power supply circuit, and in particular, a power factor correction rectifier circuit for controlling a switching element has been proposed in order to match an input voltage waveform and an input current waveform to obtain an optimum power factor. .

For example, a boost type power factor as shown in FIG.
In the improved rectifier circuit, the input voltage V_iIs the diode D_1a, D
_1b, D_1c, D_1dInput to the main rectifier composed of. Entering
The output voltage is full-wave rectified by the main rectifier and
Inductor L for the burner ₁, Switching element
Q₁, Diode T₂And capacitor C_oOutput through
Is done.

At this time, the switching element Q ₁ is on / off controlled by the control circuit cont so that the input current waveform I _i is similar to the input voltage waveform V _i . Therefore, the switching current i _L flowing through the inductance L ₁ , the diodes D _1a , D _1b , D _1c , and D _1d.
Has a waveform as shown in FIG. Further, the input current waveform I _i is the input voltage waveform V as shown in FIG.
_i (Fig. 6 (a)) and the power factor of the input power is 1
It becomes 00%, and harmonic distortion does not occur.

When the power used in the device increases, the main rectifier also becomes large, and the generation of EMI noise becomes a problem due to the switching current flowing in the main rectifier. In order to reduce such EMI noise, it is possible to insert a filter circuit on the output side of the main rectifier. For example,
As shown in FIG. 5, by providing the filter capacitor C _f ′ on the output side of the main rectifier, the switching current flowing in the main rectifier can be reduced and the EMI noise can be reduced. (B) The ultrasonic diagnostic apparatus usually includes a power supply circuit connected to an AC power supply. A switching regulator is often used as a power supply circuit, and in particular, a power factor correction rectifier circuit has been proposed that controls a switching element to obtain an optimum power factor by matching an input voltage waveform and an input current waveform. The output of the power factor correction rectifier circuit is supplied to the primary side of the DC / DC converter and output as a desired DC voltage.

[0006]

[Problems to be Solved by the Invention]

(A) In the circuit in which the filter capacitor C _f ′ in FIG. 5 is inserted, the waveform of the output voltage V _A of the main rectifier is distorted as shown in FIG. 7 (b). The control circuit cont which controls the switching element Q ₁ is supplied with the control current I _c based on the output voltage V _A from the main rectifier via the reference signal extracting resistor R _c , and based on this, the switching element Q 1 is supplied. ₁ control is performed.
Therefore, when there is a waveform distortion in the output voltage V _A of the main rectifier, the input current waveform I _i is distorted as shown in FIG. 7D, the power factor of the input power is lowered, and the harmonic component is generated. Occurs.

An object of the present invention is to mount a power supply circuit capable of improving the power factor of input power from an AC power supply and removing EMI noise in an ultrasonic diagnostic apparatus. (B) In a switching regulator consisting of a power factor correction rectifier circuit and a DC / DC converter, if the operation of the power factor correction rectifier circuit is stopped for some reason, the rectifier circuit becomes a capacitor input type and the power factor drops significantly. And the input volt ampere becomes too large.

It is an object of the present invention to stop the operation of the DC / DC converter even when the operation of the power factor correction rectifier circuit in the power supply circuit provided in the ultrasonic diagnostic apparatus is stopped, and the input volt ampere becomes excessive. It is to prevent becoming.

[0009]

[Means for Solving the Problems]

(A) The ultrasonic diagnostic apparatus according to the present invention has a power supply circuit connected to an AC power supply, and the power supply circuit includes a first rectifying bridge circuit, a filter circuit, a power factor improving switching circuit, and A two-rectifier bridge circuit and a control circuit are provided. The first rectifying bridge circuit is connected to the AC power supply.
The filter circuit is inserted on the output side of the first rectifying bridge circuit. The power factor improving switching circuit shapes the current waveform input from the first rectifying bridge circuit.
The second rectifying bridge circuit is connected in parallel with the first rectifying bridge circuit. The control circuit controls the power factor improving switching circuit based on the voltage waveform input from the second rectifying bridge circuit. (B) The ultrasonic diagnostic apparatus according to the present invention has a power supply circuit connected to an AC power supply, and the power supply circuit includes a main rectifier, a power factor improving switching circuit, a first control circuit, A DC / DC converter, a DC / DC converter switching circuit, and a second control circuit are provided. The main rectifier is connected to the AC power supply. The power factor improving switching circuit shapes the current waveform input from the main rectifier.
The first control circuit controls the power factor improving switching circuit based on the input voltage from the main rectifier. The output voltage of the main rectifier is given to the DC / DC converter via the switching circuit for power factor correction. The switching circuit for the DC / DC converter turns on / off the primary side of the DC / DC converter. The second control circuit, based on the switching current generated by the operation of the power factor correction switching circuit, performs DC / D
It controls the switching circuit for the C converter.

[0010]

[Action]

(A) The ultrasonic diagnostic apparatus according to the present invention has a power supply circuit connected to an AC power supply, and the AC power supply is input via the first rectifying bridge circuit. The filter circuit is inserted on the output side of the first rectifying bridge circuit and removes EMI noise based on the switching current flowing in the power factor improving switching circuit. The power factor improving switching circuit is controlled by the control circuit based on the voltage waveform input from the second rectifying bridge circuit, and shapes the current waveform input from the first rectifying bridge circuit. The second rectifying bridge circuit is connected in parallel with the first rectifying bridge circuit, and the reference signal of the control circuit is taken out regardless of the waveform distortion caused by the filter circuit. Therefore, the input current waveform of the power supply circuit becomes similar to the input voltage waveform, the power factor is improved, and the EMI noise due to the switching current can be removed. (B) In the ultrasonic diagnostic apparatus according to the present invention, in the power supply circuit connected to the AC power supply, the main rectifier performs full-wave rectification on the AC power supply, and the power factor improving switching circuit shapes the current waveform. The current waveform at this time is controlled by the first control circuit, and an input current waveform similar to the input voltage from the main rectifier is output. The output of the main rectifier is DC
It is supplied to the primary side of the / DC converter and is output as the required DC voltage. At this time, the second control circuit is on / off controlled based on the switching current generated by the operation of the power factor correction switching circuit. When the power factor correction rectifier circuit including the first control circuit and the power factor correction switching circuit is stopped, the DC / DC converter switching circuit is stopped to prevent the input volt ampere from becoming excessive.

[0011]

【Example】

(A) FIG. 1 is a control block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus in which an embodiment of the present invention is adopted. In the figure, a probe 1 is composed of a plurality of micro-vibrators and is connected to a transmission / reception control circuit 2. The transmission / reception control circuit 2 includes a transmission control circuit unit including a high-frequency pulse oscillator for transmitting an ultrasonic beam by the probe 1, a reception preamplifier unit for amplifying a reflected echo signal, a reception delay circuit unit for performing an electronic focusing method, and a slice. A reception waveform shaping circuit unit including a logarithmic compression circuit and a low-pass filter for obtaining information is provided.

An image memory writing circuit 3 is connected to the transmission / reception control circuit 2. Image memory writing circuit 3
Is a buffer for temporarily storing the sample point data from the transmission / reception control circuit 2, an interpolation calculation circuit section for calculating the data to be stored in the memory pixel of the image memory based on the sample point data, and the data to the image memory. A write address generation unit for writing is provided. A scanning control circuit 4 is connected to the transmission / reception control circuit 2 and the image memory writing circuit 3. The scan control circuit 4 controls the reception delay time of the reception delay circuit section of the transmission / reception control circuit 2.
Further, the scanning control circuit 4 controls the interpolation calculation circuit unit of the image memory writing circuit 3 to control the interpolation coefficient based on the reception direction of the ultrasonic beam and the sample data. Further, the scanning control circuit 4 controls the write address generator 14 of the image memory write circuit 3 to generate a write address to the image memory.

The image memory circuit 5 is mainly composed of a two-dimensional frame memory in which memory pixels are arranged in a matrix corresponding to a display image. The image memory reading circuit 6 reads the image data such as tomographic data stored in the image memory circuit 5 in synchronization with the TV signal and outputs it to the display device 7. The display device 7 is composed of a CRT monitor or the like. Further, a power supply circuit 8 is connected to the transmission / reception control circuit 2, the image memory writing circuit 3, the scanning control circuit 4, the image memory circuit 5, the image memory reading circuit 6 and the display device 7. The power supply circuit 8 is connected to a commercial AC power supply, and outputs and supplies necessary power to each circuit.

FIG. 2 is a circuit diagram of an embodiment of the power supply circuit. This circuit constitutes a boost type power factor correction rectifier circuit. Diode _{D 1a, D 1b, D 1c} , the first rectifier bridge circuit 11 comprised of D _1d is connected to an AC power source of a commercial, the input voltage V _i is supplied. This input voltage V
_i is full-wave rectified by the first rectifying bridge circuit 11,
It is output via the inductance L ₁ for the boost converter, the switching element Q ₁ , the diode D ₂ and the capacitor C _o . The input voltage V _i is input to the first rectifying bridge circuit 11 and is also input to the second rectifying bridge circuit 12 in parallel with it. The second rectifying bridge circuit 12 is composed of diodes D _3a , D _3b , D _3c and D _3d . The output of the second rectifier bridge circuit 12 is controlled through a resistor R _c of the reference signal extraction circuit 13
Has been entered in. A filter capacitor C _f ′ is inserted on the output side of the first rectifying bridge circuit 11. The output side of the first rectifying bridge circuit 11 is further connected with an inductor L ₁ for a boost converter, a switching element Q ₁ , a diode D ₂ and a capacitor C _o . The switching element Q ₁ is on / off controlled under the control of the control circuit 13 so that the input current waveform I _i becomes similar to the input voltage waveform V _i .

The reference signal of the control circuit 13 is the second signal.
Since the input voltage waveform rectified by the rectifying bridge circuit 12 is used, the control signal for the switching element Q ₁ can be created regardless of the operation of the filter capacitor C _f ′. Further, the switching current i _L generated by the switching element Q ₁ flows through the filter capacitor C _f ′ and the inductance L ₁ , so that the switching current does not flow in the first rectifying bridge circuit 11 and EMI noise is reduced. Is possible.

By this power factor correction rectifier circuit, the input current waveform I _i becomes similar to the input voltage waveform V _i as in FIG. 6D, and harmonic distortion occurs when the power factor of the input power is 100%. Absent. (B) FIG. 3 is a circuit diagram of another embodiment of the power supply circuit.
This circuit constitutes a boost type power factor correction rectifier circuit. A commercial AC power supply is connected to the main rectifier 21 composed of the diodes D _4a , D _4b , D _4c , and D _4d , and the input voltage V _AC is supplied. This input voltage V _AC is applied to the main rectifier 2
1 is full-wave rectified, and the boost converter has an inductance L ₂ , a switching element Q ₂ , and a diode D _7.
And is output via the capacitor C ₃ .

The switching element Q ₂ is ON / OFF controlled by the first control circuit 22 to shape the input current waveform of the rectifying circuit and improve the power factor. The output voltage of the main rectifier 21 is applied to the first control circuit 22, and the switching element Q ₂ is controlled based on this voltage waveform. The output of the power factor correction rectifier circuit is input to the DC / DC converter. DC / DC converter, transformer T _1, transformer T ₁ of the primary on-switching element for turning off Q _3, second control circuit 23 performs on-off control of the switching element Q _3, the transformer T ₁ The secondary side includes a diode D ₈ , an inductance L ₃ , a capacitor C _O , and a load resistance R _O.

The voltage V _C is induced in the secondary winding provided in the inductance L ₂ by the switching current I _L2 flowing in the inductance L ₂ based on the on / off operation of the switching element Q ₂ . The voltage V _C is the power supply voltage of the first control circuit 22 via the diode D ₅ and the capacitor C 1. At the same time, the voltage V _C is rectified via the diode D ₆ and the capacitor C ₂ , and E
The N signal is input to the second control circuit 23.

When the voltage V _AC input from the AC power source to the main rectifier 21 has a waveform as shown in FIG. 4 (a), the main rectifier 21 performs full-wave rectification on the switching element Q.
_The switching current I _L2 whose power factor is improved by ₂ has a waveform as shown in FIG. Along with this, the electromotive force V _C generated on the secondary side of the inductance L ₂ has a waveform as shown in FIG. Based on this voltage V _C , the EN signal input to the second control circuit 23 has a constant value when the switching current I _L2 is normal, as shown in FIG. 4D. With this EN signal,
The second control circuit 23 operates the switching element Q _3, and the output voltage V _O of the DC / DC converter outputs a predetermined DC voltage as shown in FIG. 4 (e).

When the power factor correction rectifier circuit is stopped for some reason, the switching current I _L2 by the switching element Q ₂ is stopped. For example, time t _{0 in} FIG.
It is assumed that the power factor correction rectification circuit stops at. At the same time, the electromotive force V _C generated on the secondary side of the inductance L ₂ also stops. Therefore, the EN signal input to the second control circuit 23 becomes 0 after the capacitor C ₂ is discharged. Thus, the second control circuit 23 to the switching element Q ₃ off.

From the above, when the operation of the power factor correction rectifier circuit is stopped, the main input rectifier 21, the diode D ₇ , and the capacitor C ₃ form a capacitor input type rectifier circuit, which is controlled by the second control circuit 23. DC / D
Since the C converter stops operating, it is possible to prevent the input volt ampere from becoming excessive.

[0022]

【The invention's effect】

(A) In the ultrasonic diagnostic apparatus according to the present invention, the power supply circuit has a power factor improving switching circuit and a control circuit for controlling the same, and the input current waveform and the input voltage waveform are similar to each other. This improves the power factor and provides efficient power supply. Further, the filter circuit removes EMI noise due to the switching current of the power factor improving switching circuit. The control circuit includes a second rectifier bridge circuit connected in parallel with the first rectifier bridge circuit in which the filter circuit is inserted on the output side.
Since the power factor correction switching circuit is controlled based on the voltage waveform of the rectification bridge circuit, the waveform distortion by the filter circuit is irrelevant to the control of the power factor correction switching circuit, and the power factor correction operation is not disturbed. (B) The ultrasonic diagnostic apparatus according to the present invention has a power supply circuit connected to an AC power supply, and the power supply circuit controls the switching circuit for power factor correction by the first control circuit to reduce the input power. The power factor is improving. Further, when the second control circuit controls the DC / DC converter switching circuit based on the switching current of the power factor improving switching circuit, when the switching current of the power factor improving switching circuit disappears ( Even when there is a stop due to an abnormality in the power factor correction rectifier circuit), the operation of the DC / DC converter can be stopped to prevent the input volt ampere from becoming excessive.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus adopting an embodiment of the present invention.

FIG. 2 is a circuit diagram of a power supply circuit according to a first embodiment of the present invention.

FIG. 3 is a circuit diagram of a power supply circuit according to a second embodiment of the present invention.

FIG. 4 is a time chart showing the signal.

FIG. 5 is a circuit diagram of a conventional power supply circuit.

FIG. 6 is a time chart showing a signal when the filter capacitor C _f ′ is omitted.

FIG. 7 is a time chart showing a signal when a filter capacitor C _f ′ is inserted.

[Explanation of symbols]

1 probe 2 transmission / reception control circuit 3 image memory writing circuit 4 scanning control circuit 5 image memory circuit 6 image memory reading circuit 7 display device 8 power supply circuit 11 first rectifying bridge circuit 12 second rectifying bridge circuit 13 control circuit 21 main rectifier 22 second 1 control circuit 23 2nd control circuit R _c resistance for reference signal extraction Q ₁ switching element L ₁ inductor C _f ′ filter capacitor Q ₂ power factor improving switching element Q ₃ DC / DC converter switching element

Claims (2)

[Claims] 1. An ultrasonic diagnostic apparatus having a power supply circuit connected to an AC power supply, wherein the power supply circuit is a first rectification bridge circuit connected to the AC power supply, and an output of the first rectification bridge circuit. A filter circuit inserted on the side, a power factor improving switching circuit for shaping a current waveform input from the first rectifying bridge circuit, and a second rectifying bridge connected in parallel with the first rectifying bridge circuit. An ultrasonic diagnostic apparatus comprising: a circuit; and a control circuit that controls the power factor improving switching circuit based on a voltage waveform input from the second rectifying bridge circuit. 2. An ultrasonic diagnostic apparatus having a power supply circuit connected to an AC power supply, wherein the power supply circuit shapes a main rectifier connected to the AC power supply, and a current waveform input from the main rectifier. A power factor improving switching circuit, a first control circuit for controlling the power factor improving switching circuit based on an input voltage from the main rectifier, and the main rectifier via the power factor improving switching circuit. DC / DC converter to which the output voltage of the DC / DC converter is applied, and D for turning on / off the primary side of the DC / DC converter
An ultrasonic diagnostic apparatus comprising: a C / DC converter switching circuit; and a second control circuit that controls the DC / DC converter switching circuit based on a switching current generated by the operation of the power factor correction switching circuit.