JP2001320137A - Electronic device mounting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device mounting apparatus where a strong magnetic field is prevented from generating at the center of a slit due to a current flowing around it, related to the electronic device mounting apparatus where a power-source pattern and a ground pattern of a plurality of electronic devices are isolated with a slit and the like. SOLUTION: A slit 6 for isolating an input circuit 4 from an output circuit 5 is formed on a printed circuit board 1 where, comprising a power-source pattern and a ground pattern, the input circuit and output circuit are mounted, with a high-frequency connection element provided around the slit which connects the power-source pattern to the ground pattern at high frequency mode. Since the power-source pattern is connected at high frequency mode to the ground pattern, the high-frequency current generating around the slit does not flow along the slit and can suppress increase of synthetic magnetic field generated by current and radiation noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device mounted with an electronic device, and more particularly to a structure in which a power supply pattern and a ground pattern of a printed circuit board are cut to isolate the electronic device, thereby separating the electronic devices. The present invention relates to an electronic device mounted device.

[0002]

2. Description of the Related Art In recent years, a variety of functions have been required for devices on which electronic devices are mounted. To meet this demand, a plurality of electronic devices each having its own function are mounted on a single printed circuit board. It is becoming. An electronic device mounted device in which a plurality of electronic devices are mounted on one printed circuit board will be described with reference to the drawings.

FIG. 9 shows a printed circuit board pattern diagram of a conventional electronic device-mounted device. As shown in FIG. 9, a conventional electronic device-mounted device includes a printed circuit board 91.
An input unit 92 and an output unit 93 are provided above as an interface with the outside. A circuit connected to the input unit 92 is an input circuit 94, and a circuit connected to the output unit 93 is an output circuit 95. Each circuit is provided with a power supply pattern and a ground pattern. An input signal input to the input circuit 94 via the input unit 92 is processed by the input circuit 94 and transmitted to the output circuit 95. The transmitted signal is processed by the output circuit 95 and output from the output unit 93 as an output signal.

The input circuit 94 and the output circuit 95 on the printed circuit board 91 have their power and ground patterns cut by slits 96, thus physically separating the input circuit 94 and the output circuit 95. By doing so, isolation between the input circuit 94 and the output circuit 95 can be realized, and the input signal does not affect the output signal via the power supply pattern and the ground pattern. No circuit operation is realized.

[0005]

However, in a conventional electronic device-equipped device, the power supply pattern and the ground pattern of the printed circuit board 91 are cut by the slit 96, so that the impedance of the power supply pattern and the impedance of the ground pattern are reduced. Is higher than when no is provided. As a result of the high impedance, there is a problem that a potential difference occurs, a current flows in the power supply pattern, and electromagnetic radiation noise caused by the current is generated.

[0006] This problem will be described with reference to FIGS. 10 and 11. FIG. 10 is a diagram showing a state in which a current flows through a power supply pattern of a printed circuit board. FIG.
0 is a cross-sectional view taken along line AA ′. As shown in FIG. 10, a slit 106 provided on the printed circuit board 101 is provided.
Currents 102 and 103 flow along both ends of. As a result, as shown in FIG.
And a magnetic field 105 due to the current 103 is generated.

Here, since the magnetic field 104 is a magnetic field generated by the current 102 flowing in the front, the direction thereof is counterclockwise as shown in the figure. On the other hand, since the magnetic field 105 is a magnetic field generated by the current 104 flowing from the near side to the back, the direction is clockwise. Since the directions of these magnetic fields near the center of the slit 106 are the same, a combined magnetic field 107 is formed. This combined magnetic field 107 is composed of the magnetic fields 104, 1
It can be seen that the magnetic field strength is clearly larger than that of the magnetic field strength of the magnetic field of the magnetic field of the magnetic field.

Although the radiation noise increases in proportion to the intensity of the magnetic field generated in the slit 106, in recent electronic equipment, the level of the radiation noise is set as a standard in order to prevent malfunction due to the radiation noise. And
There is a problem that the electronic device becomes defective due to the radiation noise.

The magnetic field generated in the electronic device will be described with reference to FIGS. FIG. 5 is a diagram for explaining a method of measuring the magnetic field intensity distribution. FIGS. 6 to 8 are magnetic field intensity distribution diagrams actually measured by the method of FIG. 5, and FIG. a), FIG. 7 shows FIG.
(C) and FIG. 8 correspond to FIG. 5 (b). In this measurement example, the electronic component 52 is mounted on the printed circuit board 51, and the loop surface of the loop antenna 53 is moved in the X direction (horizontal direction in the figure), the Y direction (vertical direction in the figure), and the Z direction (the direction in the figure). The measurement is performed in different directions (front and back directions).

In FIG. 5A, a loop antenna 53 having a loop surface set in parallel with the substrate surface of the printed circuit board 51 is shown.
Is provided, and the loop antenna 53 is scanned in the X and Y directions, and the magnetic field linked to the loop antenna 53 at each point is measured. The measurement direction at this time is defined as a Z-axis measurement direction. Similarly, in FIG. 5B, a loop surface is set in parallel with the XZ plane of the printed circuit board 51, and the loop antenna 53 is set in the X direction.
Scan in the -Y direction, and measure the magnetic field linked to the loop antenna 53 at each point (X-axis measurement direction). And FIG.
In (c), the loop surface is set parallel to the YZ plane of the printed circuit board 51, the loop antenna 53 is scanned in the XY directions, and the magnetic field linked to the loop antenna 53 at each point is measured. (Y-axis measurement direction).

First, FIG. 6 shows magnetic field distribution data measured in the Z-axis measurement direction in FIG. As can be seen from FIG. 6, the vicinity of the center of the slit position 61 is a white display indicated by the magnetic field strength 62 and the magnetic field strength is large, but the other substrates have a small magnetic field strength as shown by each pattern. I have. This is because the combined magnetic field 107 at the center of the slit shown in FIG.
This is because the magnetic field was measured as a magnetic field interlinking the loop surface of the loop antenna set on the axis, and the state of generation of the magnetic field in FIG. 11 can be confirmed from the magnetic field distribution data in FIG.

Next, it is confirmed from the measurement data that a current flows through the slit of the printed circuit board. FIG.
FIG. 6 is a diagram showing magnetic field distribution data measured in the Y-axis measurement direction in FIG. In this measurement method, the magnetic field generated around the current interlinks with the loop surface of the loop antenna and can be measured as the magnetic field strength. Therefore, the direction in which the current flows and the loop surface are the same. As shown in FIG. 7, since the magnetic field strength on both sides in the vertical direction of the slit position 71 is large, it can be seen that current flows on both sides in the vertical direction of the slit. Thus, the presence of the currents 102 and 103 shown in FIG. 10 can be confirmed from the measurement data.

Similarly, referring to FIG. 8 showing magnetic field distribution data in the X-axis measurement direction, since the magnetic field intensity is large at the upper and lower ends of the slit position 81, it can be seen that a current flows along the slit. It can be determined by the data. From the above experimental results, when a slit is provided to realize the isolation between the input circuit and the output circuit, the impedance of the power supply pattern and the ground pattern increases, so that a current flows along the slit. It can be confirmed that a magnetic field is generated and radiation noise is generated accordingly.

As a technique related to the above problem, there is JP-A-06-085408. In this publication,
A multilayer printed circuit board device has been proposed in which a slit is provided in a ground layer of a printed circuit board to separate a signal return path, and this technique will be described with reference to FIG.

FIG. 12 is a plan view showing a printed wiring board in which a slit is provided in a ground layer of a printed circuit board. FIG.
As shown in the figure, in this technique, the slit 1 in the ground layer is used.
26, the bus signal 125 and the control / interrupt signal 12
The return path of No. 4 is separated so that the switching noise does not enter the circuit section other than the signal generating circuit. However, when the current flowing in the ground layer flows in opposite directions to both ends of the slit 126 due to the slit 126 in the ground layer, the magnetic fields generated by the respective currents are combined, and a strong magnetic field is generated above the slit 126,
As described above, there is a problem that the radiation noise increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a main object of the present invention is to provide an electronic device mounted device in which a power supply pattern and a ground pattern of a plurality of mounted electronic devices are separated by a slit or the like. An object of the present invention is to provide an electronic device mounted device capable of preventing a strong magnetic field from being generated at the center of a slit due to a current flowing through the electronic device.

[0017]

To achieve the above object, the present invention provides a circuit board having a power supply pattern and a ground pattern, on which a plurality of electronic devices connected to the power supply pattern and the ground pattern are mounted. In the electronic device mounted device, at least between the electronic device of the circuit board, a groove for separating the power supply pattern and the ground pattern, the power supply pattern and the ground around the groove It is provided with means for connecting a pattern with a high frequency.

In the present invention, the means for high-frequency connection may include a capacitor or a capacitor and a coil connected in series.

Further, in the present invention, it is preferable that the plurality of electronic devices include an input electronic device for receiving an input signal and an output electronic device for transmitting an output signal.

Further, in the present invention, the circuit board may be formed of a multilayer wiring board, and the power supply pattern and the ground pattern may be formed on different layers, respectively. Preferably, a magnetic material is provided between the layer on which the ground pattern is formed and the layer on which the ground pattern is formed.

According to the present invention, since the power supply pattern and the ground pattern around the groove are connected at a high frequency by the above configuration, even if a current flows around the slit, the current does not flow along the slit, but is generated by the current. An increase in a magnetic field and radiation noise can be suppressed.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In one preferred embodiment, an electronic device-mounted apparatus according to the present invention has a power supply pattern and a ground pattern, and has an input circuit (4 in FIG. 1) and an output circuit (5 in FIG. 1). ) Is formed on the printed circuit board (1 in FIG. 1) on which the input circuit and the output circuit are separated, and a power supply pattern and a ground pattern are connected by high frequency around the slit. The high-frequency connection between the power supply pattern and the ground pattern does not allow the high-frequency current generated around the slit to flow along the slit, increasing the combined magnetic field and radiation noise generated by the current. Can be suppressed.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

[Embodiment 1] An electronic device-mounted apparatus according to a first embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a printed circuit board mounting diagram of an electronic device-mounted device according to the first embodiment.

As shown in FIG. 1, the electronic device-mounted apparatus of this embodiment has an input unit 2 and an output unit 3 on a printed circuit board 1 as an interface with the outside. The circuit connected to the input unit 2 is the input circuit 4, and the circuit connected to the output unit 3 is the output circuit 5. An input signal input to the input circuit 4 via the input unit 2 is processed by the input circuit 4 and transmitted to the output circuit 5. The transmitted signal is processed by the output circuit 5 and output from the output unit 3 as an output signal.

The power supply pattern and the ground pattern of the input circuit 4 and the output circuit 5 on the printed circuit board 1 are cut by the slit 6. This is the input circuit 4
And the output circuit 5 are physically separated to realize isolation between the input circuit and the output circuit.
By providing the slit 6, it is possible to prevent an input signal from being directly output, thereby realizing a circuit operation without malfunction as an electronic device mounted device.

However, when the power supply pattern and the ground pattern of the printed circuit board 1 are cut by the slit 6, the input circuit 4 and the output circuit 5 are isolated, but the impedance of the power supply pattern and the impedance of the ground pattern are reduced. The impedance becomes higher than when the slit 6 is not provided. Then, as a result, a potential difference occurs, and a current flows through both ends of the slit 6 provided in the power supply pattern.

Therefore, in this embodiment, the high-frequency connection element 7 is connected to a power supply pattern around the slit 6 in order to prevent a current from flowing to both ends of the slit 6. The high-frequency connection element 7 has two electrodes, one of which is connected to a power supply pattern and the other is connected to a ground pattern. Here, the high-frequency connection element 7 has such characteristics that the impedance becomes lower as the frequency becomes higher in an open state where the impedance is higher in direct current. Therefore, when a high-frequency current flows around the slit 6, the high-frequency connection element 7, which has a low impedance at a high frequency, allows a current to flow from the power supply pattern to the ground pattern, thereby preventing generation of a current along the periphery of the slit 6. Thereby, the slit 6
No synthetic magnetic field is generated near the center of the slit 7 due to the surrounding current.

As described above, in the electronic device mounted device of the present embodiment, even if the slit 6 is provided for the isolation between the input circuit 4 and the output circuit 5, the slit 6
By providing the high-frequency connection element 7 in the power supply pattern surrounding the power supply pattern and connecting one to the power supply pattern and the other to the ground pattern, a high-frequency current flowing around the slit 6 can flow to the ground pattern. Along the current does not flow, it is possible to prevent generation of a synthetic magnetic field near the center of the slit 6. Therefore, isolation between the input electronic device and the output electronic device can be reliably realized without increasing radiation noise.

In this embodiment, the case where the input device and the output device are used as the electronic device has been described. However, the present invention is not limited to the above embodiment, and other electronic devices may be mounted. The same applies to an electronic device mounted device having a configuration in which a power supply pattern and a ground pattern between each electronic device are cut off, and a high frequency connection is made between the power supply pattern and the ground pattern at the cut portion. Can be applied to Further, the power supply pattern and the ground pattern of the input circuit 4 and the output circuit 5 described in the present embodiment may be formed on the same layer of the substrate or on different layers.

[Embodiment 2] Next, an electronic device-mounted apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a printed circuit board mounting diagram of an electronic device-mounted device according to the second embodiment. The difference between this embodiment and the first embodiment is that a capacitor is used as a high-frequency connection element provided around the slit.

As in the first embodiment, the electronic device-mounted device of this embodiment has an input section 22, an output section 23, an input circuit 24, and an output circuit 25 on a printed circuit board 21. An input signal input to the input circuit 24 via the unit 22 is processed by the input circuit 24 and transmitted to the output circuit 25. The transmitted signal is processed by the output circuit 25 and output from the output unit 23 as an output signal.

Further, since the power supply pattern and the ground pattern of the printed circuit board 21 are cut by the slit 26, the impedance of the power supply pattern and the ground pattern becomes higher than when the slit 26 is not provided. As a result, a potential difference occurs, and current flows through both ends of the slit 26 provided in the power supply pattern.

Therefore, in this embodiment, a capacitor 27 is provided in the power supply pattern around the slit 26, and the capacitor 2
One electrode 7 is connected to a power supply pattern, and the other electrode is connected to a ground pattern. The capacitor 27 has a characteristic that the impedance becomes low as the frequency increases in an open state where the direct current has a high impedance, and when a high frequency current flows around the slit 26, the capacitor 27 has a low impedance at a high frequency. A current flows from the power supply pattern to the ground pattern, and no current flows along the periphery of the slit 26. Thereby, the slit 26
The disadvantage that a synthetic magnetic field is generated near the center of the slit 26 due to the surrounding current can be prevented.

As described above, in the electronic device-mounted apparatus according to the present embodiment, the slit 26 is provided for isolating the input circuit 24 and the output circuit 23, as in the first embodiment.
However, since the high frequency current flowing around the slit 26 flows to the ground pattern due to the capacitor 27 provided in the power supply pattern around the slit 26, no current flows along the periphery of the slit 26, The generation of a combined magnetic field near the center can be prevented. Thus, isolation between the input and output electronics can be reliably achieved without increasing radiated noise.

It is to be noted that the present invention can be similarly applied to an electronic device mounted with a plurality of other electronic devices as the electronic device, and the power supply pattern and the ground pattern of the input circuit 24 and the output circuit 25 are printed. The circuit board 21 may be formed on the same layer or on a different layer as in the first embodiment.

[Embodiment 3] Next, an electronic apparatus mounted apparatus according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a printed circuit board mounting diagram of an electronic device-mounted device according to the third embodiment. This embodiment differs from the first and second embodiments in that a capacitor and a coil are provided around the slit.

As shown in FIG. 3, the electronic device mounted device according to the third embodiment has an input section 32, an output section 33, an input circuit 34, and an output circuit 35 on a printed circuit board 31. The input signal input via the unit 32 is processed by the input circuit 34 and the output circuit 35,
Is output as an output signal. Further, the power supply pattern and the ground pattern of the printed circuit board 31 are slit 3
6, the impedance of the power supply pattern and the ground pattern becomes higher than when no slit is provided, thereby causing a potential difference, and a current flows through both ends of the slit 36 provided in the power supply pattern.

Therefore, in this embodiment, the capacitor 37 and the coil 38 are connected to the power supply pattern around the slit 36. One electrode of the capacitor 37 is connected to the power supply pattern, the other electrode is connected to the coil 38, and one electrode of the coil 38 is connected to the capacitor 37 and the other electrode is connected to the ground pattern. Since the capacitor 37 is in an open state having a high impedance in direct current, no current flows between the power supply pattern and the ground pattern.

Here, in this embodiment, the capacitor 37 and the coil 38 are connected in series between the power supply pattern and the ground pattern, and resonance occurs due to the capacitance of the capacitor 37 connected in series and the inductance of the coil 38. , And the impedance becomes low at the resonance frequency. The resonance frequency f can be obtained by the following equation, where L is the inductance of the coil 38 and C is the capacitance of the capacitor 37.

F = 1 / {2π} (LC)}

When a high-frequency current having a resonance frequency flows around the slit 36, a current flows from the power supply pattern to the ground pattern due to series resonance of the capacitor 37 and the coil 38, which have low impedance at the resonance frequency. Therefore, no current flows along the periphery of the slit 36, and a current around the slit 36 does not generate a combined magnetic field near the center of the slit 36. Thus, isolation between the input and output electronics can be reliably achieved without increasing radiated noise.

Note that the present invention can be similarly applied to an electronic device mounted with a plurality of other electronic devices as the electronic device. The power supply pattern and the ground pattern are formed on the same layer of the printed circuit board 31. It may be formed in different layers as in the first and second embodiments.

[Embodiment 4] Next, an electronic apparatus mounted apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a printed circuit board mounting diagram of an electronic device-mounted device according to the fourth embodiment. This embodiment is different from the above-described first to third embodiments in that a magnetic material is provided around the slit in this embodiment.

As shown in FIG. 4, the electronic device-mounted device has an input section 42, an output section 43, an input circuit 44, and an output circuit 45 on a printed circuit board 41. Is input to the input circuit 44 and the output circuit 45 and output from the output unit 43 as an output signal. Further, since the power supply pattern and the ground pattern of the printed circuit board 41 are cut by the slits 46, the power supply pattern and the ground pattern have high impedance, so that current flows through both ends of the slits 46 provided in the power supply pattern.

Here, the present embodiment is characterized in that a magnetic material 47 is mounted on the power supply pattern around the slit 46. Since the magnetic material 47 has a property of high impedance at a high frequency due to its material characteristic of magnetic permeability, the power supply pattern around the slit 46 is
The high impedance makes it difficult for current to flow. Thereby, the slit 46 due to the current around the slit 46
The generation of a synthetic magnetic field near the center can be prevented. Thus, isolation between the input and output electronics can be reliably achieved without increasing radiated noise.

It should be noted that the present invention can be similarly applied to an electronic device mounted with a plurality of other electronic devices as the electronic device, and the power supply pattern and the ground pattern are formed on the same layer of the printed circuit board 41. It may be formed in a different layer as in the first to third embodiments.

[0048]

As described above, according to the present invention,
A plurality of electronic devices such as an input electronic device and an output electronic device are mounted, and an electronic device mounted device in which a power supply pattern and a ground pattern between each electronic device are cut by a slit or the like flows around the slit due to the pattern cutting. It is possible to prevent generation of a current and synthesis of a magnetic field caused by the current, thereby suppressing an increase in radiation noise.

The reason is that a high-frequency current generated in the power supply pattern can flow through the ground pattern by connecting the power supply pattern at the cut portion and the ground pattern at a high frequency using a capacitor, a coil, a magnetic material, or the like. Because.

[Brief description of the drawings]

FIG. 1 is a printed circuit board mounting diagram of an electronic device-mounted device according to a first embodiment of the present invention.

FIG. 2 is a printed circuit board mounting diagram of an electronic device-mounted device according to a second embodiment of the present invention.

FIG. 3 is a printed circuit board mounting diagram of an electronic device-mounted device according to a third embodiment of the present invention.

FIG. 4 is a printed circuit board mounting diagram of an electronic device-mounted device according to a fourth embodiment of the present invention.

FIG. 5 is a diagram illustrating a method of measuring a magnetic field intensity distribution on a printed circuit board using a loop antenna.

FIG. 6 is a diagram illustrating a magnetic field intensity distribution on a printed circuit board in a Z-axis measurement direction.

FIG. 7 is a diagram illustrating a magnetic field intensity distribution on a printed circuit board in a Y-axis measurement direction.

FIG. 8 is a diagram illustrating a magnetic field intensity distribution on a printed circuit board in an X-axis measurement direction.

FIG. 9 is a printed circuit board mounting diagram of a conventional electronic device-mounted device.

FIG. 10 is a diagram illustrating a current direction of a printed circuit board of a conventional electronic device-mounted device.

FIG. 11 is a cross-sectional view illustrating a current magnetic field direction of a printed circuit board of a conventional electronic device-mounted device.

FIG. 12 is a printed circuit board mounting diagram of a conventional electronic device-mounted device.

[Explanation of symbols]

1,21,31,41,51,91,101,121
Printed circuit board 2, 22, 32, 42, 92 Input unit 3, 23, 33, 43, 93 Output unit 4, 24, 34, 44, 94 Input circuit 5, 25, 35, 45, 95 Output circuit 6, 26 , 36, 46, 96, 106, 126 Slit 7 High-frequency connection element 27, 37 Capacitor 38 Coil 47 Magnetic material 52 Electronic component 53 Loop antenna 61, 71, 81 Slit position 62, 72, 82 Magnetic field strength 102, 103 Current 104 , 105 Magnetic field 107 Synthetic magnetic field 122 LSI 123 Connector 124 Control / interrupt signal 125 Bus signal

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/46 H05K 3/46 Z Q F term (Reference) 5E338 BB02 BB12 BB75 CC01 CC04 CC06 CD11 EE13 5E346 AA11 AA12 AA15 BB02 BB03 BB04 BB06 CC16 CC60 FF45 GG40 HH01 5J046 AA02 AB08 UA02 5J047 AA02 AB08 FD06

Claims (6)

[Claims] 1. An electronic device-mounted device in which a plurality of electronic devices connected to the power supply pattern and the ground pattern are mounted on a circuit board having a power supply pattern and a ground pattern. At least a groove separating the power supply pattern and the ground pattern is provided between the electronic devices, and a unit is provided around the groove to connect the power supply pattern and the ground pattern at a high frequency. Electronic equipment mounted equipment. 2. The electronic device-mounted apparatus according to claim 1, wherein said high-frequency connection means includes a capacitor. 3. The electronic device-mounted apparatus according to claim 1, wherein said means for high-frequency connection includes a capacitor and a coil connected in series. 4. The apparatus according to claim 1, wherein said plurality of electronic devices include an input electronic device for receiving an input signal, and an output electronic device for transmitting an output signal. Electronic device mounted equipment. 5. The electronic device according to claim 1, wherein the circuit board is a multilayer wiring board, and the power supply pattern and the ground pattern are formed in different layers. Equipment mounted equipment. 6. The electronic device-mounted device according to claim 5, wherein a magnetic material is provided between the layer on which the power supply pattern is formed and the layer on which the ground pattern is formed. .