electronic machines
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MITSUBISHI ELECTRIC CORP
- Filing Date
- 2022-05-02
- Publication Date
- 2026-06-26
Smart Images
Figure 0007880733000001 
Figure 0007880733000002 
Figure 0007880733000003
Abstract
Description
Technical Field
[0001] The present disclosure relates to an electronic device.
Background Art
[0002] In recent years, miniaturization and high integration of electronic devices have been progressing. As a result, due to the proximity of cables and printed circuit boards or printed circuit boards to each other within an electronic device, EMC (Electromagnetic Compatibility) problems are often caused by the influence of electromagnetic field interference. Specifically, electromagnetic noise is often emitted outside the electronic device and affects other products, or electromagnetic noise often causes malfunction of other printed circuit boards within the same electronic device. In particular, a cable through which a large current flows generates a magnetic field around the cable and affects the wiring and circuits on the printed circuit board, which may cause malfunction of the electronic device. As countermeasures, there are examples such as increasing the distance between the cable and the printed circuit board, or inserting a metal plate around the printed circuit board as a shield. For example, Japanese Patent Application Laid-Open No. 2001-53482 (Patent Document 1) describes a shield structure of an electronic device that covers the periphery of a printed circuit board with a shield.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] As described in the above publication, it is possible to suppress the effects of electromagnetic noise from cables by covering the printed circuit board with a shield. However, it is necessary to suppress the effects of vibration of the shield (e.g., abnormal noise and damage due to vibration). For this reason, the strength of the shield itself and a strong connection between the shield and the components to which it is attached are required. This leads to an increase in the cost of the shield and the components, as well as the manufacturing cost of attaching the shield.
[0005] This disclosure has been made in view of the above-mentioned problems, and its purpose is to provide electronic equipment that can reduce the effects of electromagnetic noise received by a printed circuit board from a cable without using shielding. [Means for solving the problem]
[0006] The electronic device of this disclosure comprises a printed circuit board including a reference ground and at least one circuit board wiring, and a cable electrically connected to the printed circuit board. The cable is routed at a distance from the printed circuit board. When the vertical distance between the reference ground and the cable is the first distance X, and the horizontal distance between the reference ground and the circuit board wiring is the second distance Y, the circuit board wiring is given by Y = 1.8 × ln(X) using the first distance X and the second distance Y. - It is positioned as defined by 4. [Effects of the Invention]
[0007] The electronic device described herein can reduce the effects of electromagnetic noise received by a printed circuit board from a cable without the need for shielding. [Brief explanation of the drawing]
[0008] [Figure 1] This diagram schematically shows the configuration of the electronic device according to Embodiment 1. [Figure 2] This diagram schematically shows the configuration of a modified example 1 of the electronic device according to Embodiment 1. [Figure 3] This diagram schematically shows the configuration of a modified example 2 of the electronic device according to Embodiment 1. [Figure 4] This is a schematic cross-sectional view showing the structure of the electronic device according to Embodiment 1. [Figure 5] This is a schematic top view showing the structure of the electronic device according to Embodiment 1. [Figure 6] This is a schematic cross-sectional view showing the structure of the electronic device according to Embodiment 1. [Figure 7] This figure shows the circuit configuration of a printed circuit board according to Embodiment 1. [Figure 8] This figure shows the current path on the circuit of the printed circuit board according to Embodiment 1. [Figure 9] This figure shows the current path on the circuit of the printed circuit board according to Embodiment 1. [Figure 10] This figure shows the voltage waveforms on the circuit of the printed circuit board according to Embodiment 1. [Figure 11] This is a cross-sectional view showing the magnetic field on a printed circuit board according to Embodiment 1. [Figure 12] This is a cross-sectional view showing the dimensions of the electronic device according to Embodiment 1. [Figure 13] This figure shows the voltage levels of the circuit board wiring of the electronic device according to Embodiment 1. [Figure 14] This figure shows the voltage levels of the circuit board wiring of the electronic device according to Embodiment 1. [Figure 15] This figure shows the relationship between the distance from the cable to the reference ground of the electronic device according to Embodiment 1 and the distance from the reference ground, where the voltage level decreases, to the circuit board wiring. [Figure 16] This is a perspective view showing the simulation model. [Figure 17] This is a top view showing the current path of the simulation model. [Figure 18] This is a cross-sectional view showing the magnetic field in the electronic device according to Embodiment 1. [Figure 19] This is a schematic cross-sectional view showing the structure of the electronic device of Comparative Example 1. [Figure 20] This is a schematic cross-sectional view showing the structure of the electronic device of Comparative Example 2. [Figure 21]It is a diagram showing the voltage level of the board wiring of the electronic device according to Embodiment 2. [Figure 22] It is a cross-sectional view showing the dimensions of the electronic device according to Embodiment 3. [Figure 23] It is a cross-sectional view showing the dimensions of the electronic device according to Embodiment 4. [Figure 24] It is a diagram showing the relationship between the distance from the cable of the electronic device according to Embodiment 5 to the reference ground and the distance from the reference ground where the voltage level decreases to the board wiring. [Figure 25] It is a diagram showing the voltage level of the board wiring of the electronic device according to Embodiment 5. [Figure 26] It is a cross-sectional view showing the dimensions of the electronic device according to Embodiment 6.
Modes for Carrying Out the Invention
[0009] Hereinafter, embodiments will be described based on the drawings. In the following, the same or corresponding parts will be denoted by the same reference numerals, and duplicate explanations will not be repeated.
[0010] Embodiment 1. Referring to Figure 1, the electronic device 1 according to Embodiment 1 will be described. Figure 1 is a schematic diagram showing the electronic device 1 according to Embodiment 1. As shown in Figure 1, the electronic device 1 includes a printed circuit board 2, a cable 4, a connector 5, a connector 6, and a cable 7. The printed circuit board 2 includes board wiring 9, ICs (Integrated Circuits) 10, 11, and board wiring 12. Cable 4 connects the printed circuit board 2 to the external power supply 3. Connector 5 connects cable 4 to the printed circuit board 2. Cable 7 connects connector 5 to connector 6. Board wiring 9 connects connector 6 to the switching circuit 8. Board wiring 12 connects IC 10 and IC 11. The switching circuit 8 is an inverter circuit or a switching power supply circuit. IC 10 and IC 11 are for controlling the CPU (Central Processing Unit) and the switching circuit 8. IC 10 and IC 11 communicate with each other. Also, since the positive and negative sides of the power supply are supplied from the external power supply 3, cables 4 and 7 consist of at least two or more cables. Cables 4 and 7 are electrically connected to the printed circuit board 2.
[0011] In Figure 1, all components are configured on the same circuit board, but as shown in Figure 2, IC10 and IC11 may be configured on a separate circuit board 13 from circuit board 2. Also, as shown in Figure 3, connector 5 may be absent, and cable 4 may be connected to the external power supply 3 and connector 6.
[0012] Figure 4 is a diagram showing the structural arrangement of the electronic device 1 shown in Figure 1 from a cross-sectional view. In this application, hatching is not applied to the cross-section in the diagrams showing the cross-section for clarity. The outer surface of the electronic device 1 is composed of a housing 14. The material of the housing 14 may be a conductive material such as stainless steel or aluminum, or a non-conductive material such as resin. The printed circuit board 2 is fixed to the housing 14. The cable 7 connecting connector 5 and connector 6 is routed at a distance from the printed circuit board 2, as shown in Figure 4. The distance between the cable 7 and the printed circuit board 2 is, for example, several millimeters to tens of millimeters.
[0013] Figure 5 is a diagram showing the structural arrangement of the electronic device 1 shown in Figure 1, viewed from above. Note that, for clarity, the housing 14 is not shown in Figure 5, and connectors 5, etc., are shown with solid lines. The cable 7 between connectors 5 and 6 and the circuit board wiring 12 between ICs 10 and 11 are separated by, for example, several millimeters to tens of millimeters. The circuit block composed of ICs 10 and 11, etc., has a separate reference ground from cable 7 and is formed on reference ground 15.
[0014] Figure 6 is a diagram showing the structural arrangement of the electronic device 1 shown in Figure 1 from a cross-sectional view. Note that Figure 6 shows a different cross-section than Figure 4. Within the printed circuit board 2 is a reference ground 15 for a circuit block consisting of IC 10 and IC 11, etc. On the reference ground 15 is the board wiring 12 between IC 10 and IC 11. As shown in Figure 6, the board wiring 12 is formed on the surface layer of the printed circuit board 2. In other words, the board wiring 12 is located on the surface of the printed circuit board 2. The cable 7 shown in Figure 1 includes cable 7a and cable 7b. Cables 7a and 7b are routed above the printed circuit board 2. Cables 7a and 7b are routed above the board wiring 12 and the reference ground 15. Also, cables 7a and 7b have a diameter of, for example, 2 mm. The distance between cable 7a and cable 7b is, for example, 3 mm.
[0015] Figure 7 shows the circuit configuration of the printed circuit board 2 according to Embodiment 1. Connector 5 is the IF (interface) to the external power supply 3 and is connected to cables 4a and 4b. Connector 6 is connected to connector 5 by cables 7a and 7b. The external power supply 3 is DC, but the printed circuit board 2 may have a circuit that converts AC to DC. Capacitors 42a and 42b are mounted near connector 6. Capacitors 42a and 42b are capacitors that store charge to operate the subsequent circuit. MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) 43a, MOSFET 43b, MOSFET 43c, and MOSFET 43d are switching elements. In this embodiment, the switching elements are MOSFETs, but other switching elements such as IGBTs (Insulated Gate Bipolar Transistors) may be used. Transformer 44 is an insulating component that transmits power from the primary side (MOSFET side) to the secondary side (diode side). Because power is transmitted to the secondary side using transformer 44 during switching operation, no DC voltage is applied immediately after transformer 44. The voltage is smoothed by diode 45a, diode 45b, inductor 46, and capacitor 47 to generate a DC voltage. The generated DC voltage is output from terminals 41c and 41d. The generated DC voltage is also converted into a voltage value that can be input to IC11 by voltage detection circuit 48 and input to IC11. IC11 is the CPU. IC11 detects the voltage value generated from the input voltage. IC10 shown in Figure 1 includes IC10a and IC10b. IC10a and IC10b are insulating elements. IC10a controls the energization of MOSFET43a and MOSFET43b by controlling the gate signals of MOSFET43a and MOSFET43b. IC10b controls the energization of MOSFET43c and MOSFET43d by controlling the gate signals of MOSFET43c and MOSFET43d. The insulating elements IC10a and IC10b are controlled by the CPU IC11 to maintain a predetermined voltage value.Furthermore, IC11 communicates with other printed circuit boards via a cable connected to terminal 41e. IC11 communicates the output voltage value, as well as control information for IC10a and IC10b. The status of printed circuit board 2 can also be checked by control circuits on other printed circuit boards.
[0016] Figures 8 and 9 illustrate the operation of the power supply circuit according to Embodiment 1. The MOSFETs are switched ON / OFF depending on the combination of MOSFET 43a and MOSFET 43d, and MOSFET 43b and MOSFET 43c. Figure 8 shows the current path when MOSFET 43a and MOSFET 43d are ON and MOSFET 43b and MOSFET 43c are OFF. Figure 9 shows the current path when MOSFET 43b and MOSFET 43c are ON and MOSFET 43a and MOSFET 43d are OFF. In Figure 8, current flows in the primary circuit in the order of MOSFET 43a, transformer 44, and MOSFET 43d. In the secondary circuit, current flows in the order of transformer 44, diode 45a, and inductor 46. In Figure 9, current flows in the primary circuit in the order of MOSFET 43c, transformer 44, and MOSFET 43b. In the secondary circuit, current flows in the order of transformer 44, diode 45b, and inductor 46. By repeating the states shown in Figures 8 and 9 in this way, an arbitrary DC voltage is generated on the secondary side.
[0017] Figure 10 shows the contents of Figures 8 and 9 in terms of voltage transitions. As shown in Figure 10, the MOSFETs are switched ON / OFF by the combination of MOSFET 43a and MOSFET 43d, and MOSFET 43b and MOSFET 43c, generating a voltage on the secondary side. Inductor 46 generates a voltage when either MOSFET 43a and MOSFET 43d, or MOSFET 43b and MOSFET 43c is ON. As shown in Figure 10, the voltage across inductor 46 is pulsed, but the voltage is smoothed by inductor 46 and capacitor 47 to become a constant DC voltage. This method is called a full-bridge type. This disclosure relates to the reduction of magnetic fields generated by the current generated during switching in a switching power supply, so the method may also be a switching power supply method called a half-bridge type, flyback type, or forward type.
[0018] Figure 11 shows the magnetic field generated when current flows through cables 7a and 7b in Figure 6. Since current flows in opposite directions through cables 7a and 7b, a magnetic field is formed that forms a circle around each of cables 7a and 7b. The substrate wiring 12, which is in the same direction as cables 7a and 7b, is affected by the magnetic field. As a result, a voltage is excited on the substrate wiring 12. As shown in Figure 8, the substrate wiring 12 (12a, 12b) is connected to ICs 10a and 10b, which control MOSFETs 43a to MOSFETs 43d. The voltage excited by the magnetic field may cause ICs 10a and 10b to output incorrect signals, potentially leading to malfunction of the switching power supply circuit.
[0019] Figure 12 shows a specific configuration diagram of the electronic device 1 according to Embodiment 1. The printed circuit board 2 comprises a circuit board wiring 12, a reference ground 15, and a core material 16. The printed circuit board 2 only needs to have at least one circuit board wiring 12. The circuit board wiring 12 and the reference ground 15 are, for example, copper foil. The circuit board wiring 12 and the reference ground 15 have a thickness of, for example, 18 μm or more and 35 μm or less. Cables 7a and 7b are located away from the printed circuit board 2. The center of cable 7a and the end of the reference ground 15 are at the same horizontal position. Dimension 101 indicates the vertical distance (vertical distance) from the center of cable 7a to the reference ground 15. Dimension 101 is, for example, 10 mm. Dimension 102 indicates the vertical distance between the circuit board wiring 12 and the reference ground 15. Dimension 102 is, for example, 1 mm. Dimension 103 indicates the horizontal distance (horizontal distance) from the end of the reference ground 15 to the circuit board wiring 12. Dimension 103 varies depending on the length of dimension 101, as shown in Figure 15. Dimension 103 is set so that the board traces 12 and the reference ground 15 are positioned to minimize the impact of electromagnetic noise generated by cables 7a and 7b. Dimension 104 indicates the width of the board traces 12. Dimension 104 is, for example, 0.1 mm. Dimension 105 indicates the width of the reference ground 15. Dimension 105 is, for example, 10 mm.
[0020] Figures 13 to 15 are diagrams illustrating the effects of the electronic device 1 according to Embodiment 1. Figure 13 shows the case where dimension 101, which is the vertical distance from the center of cable 7a to the reference ground 15, is 10 mm. The diagram then shows the voltage excited in the circuit board wiring 12 by the magnetic field generated by the current flowing through cables 7a and 7b when dimension 103, which is the horizontal distance from the reference ground 15 to the circuit board wiring 12, changes. As shown in Figure 13, the voltage level decreases when dimension 103 is 2 mm.
[0021] Figure 14 shows the case where dimension 103, which is the horizontal distance from the reference ground 15 to the board wiring 12, changes in 0.1 mm increments, under the same conditions as in Figure 13. The voltage level is minimum when dimension 103 is 1.8 mm.
[0022] In Figure 15, the horizontal axis represents dimension 101, which is the vertical distance from the center of cable 7a to the reference ground 15, and the vertical axis represents dimension 103, which is the horizontal distance from the reference ground 15 to the board wiring 12. Figure 15 shows the results of simulations performed by varying dimensions 101 and 103. The board wiring position where the noise level is smallest is derived by changing the wiring position and cable position on the board. The slope of the graph shown in Figure 15 is 1.8 × ln (dimension 101), and the x-intercept is -4 The vertical distance between the reference ground 15 and cable 7a is denoted as the first distance X. The first distance X is dimension 101. The horizontal distance between the reference ground 15 and board wiring 12 is denoted as the second distance Y. The second distance Y is dimension 103. In this case, the board wiring 12 is given by Y = 1.8 × ln(X) using the first distance X and the second distance Y. - It is positioned as defined in 4. By determining the position of the circuit board wiring 12 where the voltage level is minimized when the dimension 101 is changed, as shown in Figure 15, and then routing the wiring, the circuit board wiring 12 can reduce the influence of the magnetic field caused by cables 7a and 7b.
[0023] Figures 16 and 17 are diagrams illustrating the simulation used to create Figures 13-15. Figure 16 is a perspective view showing the simulation model. Figure 17 is a top view showing the current path of the simulation model. In Figure 17, the current path is indicated by an arrow. As shown in Figures 16 and 17, one wire is placed on the board (on ground). Both ends of this wire are terminated with 50Ω resistors. The voltage of this termination is used in Figures 13-15.
[0024] Figure 18 shows the magnetic field distribution when current flows through cables 7a and 7b. The magnetic field changes depending on the direction of the current in cables 7a and 7b. Magnetic fields are generated clockwise or counterclockwise around cables 7a and 7b. The magnetic fields generated around the printed circuit board 2 are magnetic field 61 and magnetic field 62. Magnetic field 61 is a magnetic field along the reference ground 15 and is in the same direction as the magnetic field of cable 7a. In Figure 18, the magnetic field generated in cable 7a is clockwise, and the direction of magnetic field 61a is from right to left. On the other hand, magnetic field 62 is generated in the opposite direction to magnetic field 61 due to the leakage of the magnetic field. Near the point where magnetic fields 61 and 62 meet, the circuit board wiring 12 is less affected by the magnetic field, resulting in a low excited voltage.
[0025] The electronic device 1 according to Embodiment 1 is characterized in that the circuit board wiring 12 is routed in a position that is less affected by the magnetic field generated by the cable. As shown in Figure 15, the circuit board wiring 12 is routed in an optimal position determined by the distance from the cable to the reference ground and the distance from the reference ground to the circuit board wiring.
[0026] Next, the effects of the electronic device 1 according to Embodiment 1 will be explained in comparison with a comparative example. Referring to Figure 19, a countermeasure similar to that described in Patent Document 1 will be explained as Comparative Example 1. To suppress electromagnetic interference from the surroundings to the printed circuit board 2, it is effective to use a shielding structure. A shield S is provided so as to cover the circuit board wiring 12. The shield S is connected to the reference ground 15 of the circuit board wiring 12. The material of the shield S is aluminum or stainless steel. In the case of low frequencies such as commercial frequencies of 50 Hz or 60 Hz, aluminum or stainless steel cannot block the magnetic field, so a magnetic material such as iron is used for the shield S.
[0027] Referring to Figure 20, Comparative Example 2 describes a general countermeasure different from the one shown in Figure 19. The board wiring 12 is routed in the inner layer of the printed circuit board 2, rather than the surface layer. Reference grounds 15 are provided on both sides of the board wiring 12. The influence of external electromagnetic noise can be significantly reduced.
[0028] As shown in Comparative Example 1 in Figure 19 and Comparative Example 2 in Figure 20, it is possible to reduce the influence of electromagnetic noise on the substrate wiring 12. However, as shown in Comparative Example 1 in Figure 19, when a shield S is provided, a robust connection configuration is required to counter vibration and abnormal noise. This leads to increased manufacturing costs and larger electronic devices. Furthermore, in cases such as double-sided substrates, it may not be possible to provide reference grounds 15 on both sides of the substrate wiring 12, as shown in Comparative Example 2 in Figure 20. In addition, due to wiring constraints, it may be necessary to wire the substrate wiring 12 on the surface layer of the printed circuit board 2.
[0029] According to the electronic device 1 of Embodiment 1, the circuit board wiring 12 is defined using a first distance X and a second distance Y, with Y = 1.8 × ln(X) - It is positioned as defined in 4. This reduces the impact of electromagnetic noise on the printed circuit board 2 from the cable 7 without the need for shielding.
[0030] Embodiment 2. Embodiment 2 has the same configuration, operation, and effects as Embodiment 1 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and the descriptions are not repeated.
[0031] Figure 21 shows an example where the dimension 101 from cable 7a to reference ground 15 is 7 mm. Other conditions are the same as in Figure 13. In Figure 21, the minimum voltage is obtained when the dimension 103 from reference ground 15 to board wiring 12 is 2 mm.
[0032] Even when dimension 103 is 1 mm or 3 mm, there is a reduction effect of about 10 dB relative to the maximum voltage. Therefore, the voltage reduction effect can be obtained even at positions other than those derived in Figure 15. Accordingly, the board wiring 12 may be routed within a range of 1 mm from the routing position determined in Figure 15. In other words, the board wiring 12 is Y = 1.8 × ln(X) - They may be placed within a range of 1 mm from the position specified in 4.
[0033] According to the electronic device 1 of Embodiment 2, the circuit board wiring 12 is Y = 1.8 × ln(X) - It is positioned within 1 mm of the location specified in 4. This allows for a voltage reduction effect.
[0034] Embodiment 3. Embodiment 3 has the same configuration, operation, and effect as Embodiment 1 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and the descriptions are not repeated.
[0035] Figure 22 shows a case where multiple board traces 12 are provided. The printed circuit board 2 includes multiple board traces 12 and 17. Board traces 12 and 17 are provided relative to the reference ground 15. The distance of board trace 12 from the reference ground 15 is dimension 103. The distance of board trace 17 from the reference ground 15 is dimension 106. Although it is difficult to route multiple board traces to the board trace positions calculated in Figure 17, the effect of voltage reduction can be obtained if the multiple board traces are routed within 1 mm of the board trace positions calculated in Figure 15, as shown in Embodiment 2. In other words, each of the multiple board traces 12 is Y = 1.8 × ln(X) - They may be placed within a range of 1 mm from the position specified in 4.
[0036] According to the electronic device 1 of Embodiment 3, each of the multiple circuit board wirings 12 is Y = 1.8 × ln(X) - It is positioned within 1 mm of the location specified in 4. This allows for a voltage reduction effect.
[0037] Embodiment 4. Embodiment 4 has the same configuration, operation, and effect as Embodiment 1 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and their descriptions are not repeated.
[0038] Figure 23 shows the case where cables 7a and 7b are separated from those in Figure 12. The distance from the reference ground 15 to the center of cable 7a is dimension 107. Dimension 107 is, for example, 5 mm.
[0039] Figure 24 shows the distance from the cable to the reference ground and the distance from the reference ground to the PCB wiring at which the voltage level is minimized in the configuration shown in Figure 23. The distance from the cable to the reference ground is the vertical distance (up and down in Figure 23). The distance from the reference ground to the PCB wiring is the horizontal distance (left and right in Figure 23). In the configuration shown in Figure 12, the centers of the reference ground 15 and cable 7a were in the same horizontal position, but in Figure 23, the centers of the reference ground 15 and cable 7a are separated by 5 mm, so in the graph of Figure 24, they are shifted by 5 mm on the x-axis. By routing the PCB wiring 12 at a position that is the horizontal distance added to the cable's position, the voltage level can be reduced.
[0040] The horizontal distance between the reference ground 15 and cable 7a is defined as the third distance Z. The third distance Z is dimension 106. In this case, the circuit board wiring 12 is defined using the first distance X, the second distance Y, and the third distance Z as follows: Y = 1.8 × ln(X + Z) - It is positioned as defined by 4.
[0041] According to the electronic device of Embodiment 4, the circuit board wiring 12 is defined using a first distance X, a second distance Y, and a third distance Z, with Y = 1.8 × ln(X + Z) - It is positioned as defined in 4. This reduces the impact of electromagnetic noise on the printed circuit board 2 from the cable 7 without the need for shielding.
[0042] Embodiment 5. Embodiment 5 has the same configuration, operation, and effect as Embodiment 4 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and the descriptions are not repeated.
[0043] Figure 25 shows the relationship between the distance from the reference ground 15 to the board wiring 12 and the voltage level when the dimension 101 from cable 7a to the reference ground 15 is 20 mm. Other conditions are the same as in Figure 23. In Figure 25, the minimum voltage is obtained when the dimension 103 from the reference ground 15 to the board wiring 12 is 2 mm. As shown in Figure 25, even when the dimension 103 is 1 mm and 3 mm, there is a reduction effect of about 10 dB against the maximum voltage, so the voltage reduction effect can be obtained even at positions other than those derived in Figure 15. Therefore, the board wiring 12 may be routed within a range of 1 mm from the routing position determined in Figure 24. In other words, the board wiring 12 may be placed within a range of 1 mm from the position defined by Y = 1.8 × ln(X + Z) - 4.
[0044] According to the electronic device 1 of Embodiment 5, the circuit board wiring 12 is arranged within a range of 1 mm from the position defined by Y = 1.8 × ln(X + Z) - 4, thereby achieving a voltage reduction effect.
[0045] Embodiment 6. Embodiment 6 has the same configuration, operation, and effect as Embodiment 4 unless otherwise specified. Therefore, the same reference numerals are used for components identical to those in Embodiment 1, and the descriptions are not repeated.
[0046] Figure 26 shows the configuration of Figure 23, but with multiple circuit board traces. The printed circuit board 2 includes multiple circuit board traces 12 and 17. Circuit board traces 12 and 17 are provided with respect to the reference ground 15. The distance of circuit board trace 12 from the reference ground 15 is dimension 103, and the distance of circuit board trace 17 from the reference ground 15 is dimension 106. While it is difficult to route multiple circuit board traces to the circuit board trace positions calculated in Figure 24, the effect of voltage reduction can be obtained if the multiple circuit board traces are routed within 1 mm of the circuit board trace positions calculated in Figure 24, as shown in Embodiment 5. In other words, each of the multiple circuit board traces 12 may be placed within a range of 1 mm from the position defined by Y = 1.8 × ln(X + Z) - 4.
[0047] According to the electronic device 1 of Embodiment 5, each of the multiple circuit board wirings 12 is positioned within a range of 1 mm from a position defined by Y = 1.8 × ln(X + Z) - 4. This makes it possible to obtain the effect of voltage reduction.
[0048] Furthermore, the above embodiments can be combined as appropriate. The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of Symbols]
[0049] 1. Electronic equipment, 2. Printed circuit board, 3. External power supply, 4. Cable, 5. Connector, 6. Connector, 7. Cable, 8. Switching circuit, 9. Board wiring, 10. IC, 11. IC, 12. Board wiring, 13. Printed circuit board, 14. Enclosure, 15. Reference ground, 16. Core material, 17. Board wiring.
Claims
1. A printed circuit board including a reference ground and at least one board trace, The printed circuit board is equipped with a cable electrically connected to it, The cable is routed at a distance from the printed circuit board. Let the vertical distance between the reference ground and the cable be the first distance X. When the horizontal distance between the reference ground and the circuit board wiring is defined as the second distance Y, The circuit board wiring is arranged at a position defined by Y = 1.8 × ln(X) - 4, using the first distance X and the second distance Y, in an electronic device.
2. The electronic device according to claim 1, wherein the circuit board wiring is arranged within a range of 1 mm from the position defined by Y = 1.8 × ln(X) - 4.
3. The aforementioned printed circuit board includes multiple circuit board wirings, The electronic device according to claim 1, wherein each of the plurality of said circuit board wirings is located within a range of 1 mm from a position defined by Y = 1.8 × ln(X) - 4.
4. A printed circuit board including a reference ground and at least one board trace, The printed circuit board is connected to a cable, The cable is routed at a distance from the printed circuit board. Let the vertical distance between the reference ground and the cable be the first distance X. Let the horizontal distance between the reference ground and the circuit board wiring be the second distance Y. When the horizontal distance between the reference ground and the cable is defined as the third distance Z, The circuit board wiring is arranged at a position defined by Y = 1.8 × ln(X + Z) - 4, using the first distance X, the second distance Y, and the third distance Z, in an electronic device.
5. The electronic device according to claim 4, wherein the circuit board wiring is arranged within a range of 1 mm from a position defined by Y = 1.8 × ln(X + Z) - 4.
6. The aforementioned printed circuit board includes multiple circuit board wirings, The electronic device according to claim 4, wherein each of the plurality of circuit board wirings is located within a range of 1 mm from a position defined by Y = 1.8 × ln(X + Z) - 4.