Circuit board and electronic device including same

Abstract

This circuit board comprises: a first pattern; a second pattern disposed adjacent to the first pattern; a narrow pattern extending from the second pattern; a first electrode disposed to overlap the first pattern; a second electrode connected to an end portion of the narrow pattern; and a multilayer ceramic capacitor connected to the first electrode and the second electrode to electrically connect the first pattern and the second pattern. Even if a crack occurs in the multilayer ceramic capacitor, the multilayer ceramic capacitor is not ignited, so that an electronic device can be protected.

Description

Circuit boards and electronic devices having the same

[0001] The present invention relates to a circuit board having a high-frequency generating electronic component, such as a multilayer ceramic capacitor, mounted thereon, and an electronic device including the same.

[0002] Typically, many types of electronic devices equipped with CPUs and DC / DC converters have numerous multilayer ceramic capacitors mounted on printed circuit boards (PCBs).

[0003] Multilayer ceramic capacitors (MLCCs) are made by stacking multiple layers of ceramic and metal and heating them to high temperatures. They control the steady flow of current in electronic circuits. Multilayer ceramic capacitors are essential because uneven current flow in a circuit can damage the component.

[0004] As electronic devices such as smartphones and tablets increase, demand for multilayer ceramic capacitors is increasing, and demand for automotive electronic components has recently increased rapidly.

[0005] Multilayer ceramic capacitors can store more electricity the more layers they stack, so the key is to maximize the number of layers while minimizing the size of the product. However, smaller sizes also make them more susceptible to external impact, potentially leading to cracks.

[0006] When a crack occurs in a multilayer ceramic capacitor, the insulation is destroyed, a short circuit occurs between the two electrodes, and the multilayer ceramic capacitor catches fire, damaging other parts of the circuit board.

[0007] The purpose of the present invention is to provide an electronic device capable of preventing damage to the entire circuit board due to ignition caused by cracks in a multilayer ceramic capacitor.

[0008] A circuit board is provided, characterized by including a first pattern; a second pattern arranged adjacent to the first pattern; a narrow pattern extending from the second pattern; a first electrode arranged overlapping the first pattern; a second electrode connected to an end of the narrow pattern; and a multilayer ceramic capacitor electrically connecting the first pattern and the second pattern by connecting the first electrode and the second electrode.

[0009] The resistance of the above narrow pattern may have a value less than or equal to 50% of the resistance of the above multilayer ceramic capacitor.

[0010] The integrated reactance value of the above narrow pattern and the above multilayer ceramic capacitor may have a reactance value of 85% or more of the reactance value of the above multilayer ceramic capacitor.

[0011] The above narrow pattern may have a length greater than 0.75 mm and less than 1.25 mm.

[0012] The above narrow pattern may have a width of 0.125 mm or less.

[0013] The above narrow pattern has a cross-section perpendicular to the length direction of 4.375x10 -3 It can have an area of ​​less than ㎣.

[0014] The above second pattern may be ground.

[0015] The second pattern includes a recessed portion having a first side extending from the narrow pattern and being inserted in a T-shape surrounding three sides of the second electrode, and the first side has a gap corresponding to the length of the second electrode and the narrow pattern, and the second side and the third side of the recessed portion can be spaced apart from the second electrode by a gap of 0.3 mm or more.

[0016] The above first pattern may be located between the power supply unit and the DCDC converter.

[0017] A power supply unit is included that applies power to the first pattern and switches to a hiccup mode that periodically turns the power ON / OFF when an overcurrent is detected, and the narrow pattern can be disconnected within one cycle of the hiccup mode.

[0018] The capacitance of the above-mentioned multilayer ceramic capacitor may be 10uF or less.

[0019] The electronic device of the present invention can protect the electronic device by preventing ignition even if a crack occurs in the multilayer ceramic capacitor.

[0020] In addition, the electronic device of the present invention can solve a failure by partial repair by preventing damage to the entire circuit board.

[0021] In addition, the electronic device of the present invention can maintain the function of a multilayer ceramic capacitor even when a narrow pattern is added.

[0022] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0023] Figure 1 is a drawing showing a circuit board on which a laminated ceramic capacitor is mounted.

[0024] Figure 2 is a partially cutaway perspective view illustrating a laminated ceramic capacitor.

[0025] Figure 3 is a cross-sectional view of a laminated ceramic capacitor.

[0026] Figure 4 is a diagram showing the flow of current when a laminated ceramic capacitor of a conventional electronic device is damaged.

[0027] FIG. 5 is a diagram illustrating the flow of current when a laminated ceramic capacitor of an electronic device of the present invention is damaged.

[0028] Figure 6 is a conceptual diagram for explaining the configuration of the electronic device of the present invention.

[0029] Figure 7 is a table showing the pattern width at which the narrow pattern of the electronic device of the present invention is cut off.

[0030] Figure 8 is a table showing the change rate of resistance and inductance according to the size of the narrow pattern of the electronic device of the present invention and the reactance of the multilayer ceramic capacitor according to the addition of the narrow pattern.

[0031] FIG. 9 is a diagram showing the resistance and inductance according to the size of the narrow pattern of the electronic device of the present invention and the equivalent circuit of the multilayer ceramic capacitor according to the addition of the narrow pattern.

[0032] Figure 10 is a table showing the amount of reactance reduction according to the presence or absence of a narrow pattern and the capacity of a multilayer ceramic capacitor.

[0033] Figure 11 is a graph showing the hiccup mode that occurs when a multilayer ceramic capacitor is broken and the temperature change of the multilayer ceramic capacitor.

[0034] Figure 12 is a table showing the occurrence of ignition and hiccup current in a laminated ceramic capacitor according to the specifications of a narrow pattern.

[0035] Fig. 13 is a drawing showing the arrangement of the narrow pattern and the second pattern of the electronic device of the present invention.

[0036] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

[0037] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0038] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0039] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0040] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0041] Fig. 1 is a drawing illustrating a circuit board (180) on which a multilayer ceramic capacitor (185) is mounted. An electronic device may include a plurality of electronic modules having special functions and a circuit board (180) that transmits and receives signals to control each electronic module. The circuit board (180) includes a conductive band-shaped wiring (184) conductor on an insulating material by printing technology, plating technology, etching technology, or the like. Electronic components such as a plurality of integrated circuits (182) and connectors (183) for connecting to other electronic modules may be fixed to the surface of the circuit board (180) and connected between the electronic components through the wiring (184).

[0042] Multilayer ceramic capacitors may be placed at the connection points between each electronic component of a printed circuit board. Multilayer ceramic capacitors (185) (MLCC: Multilayer Ceramic Capacitor) stably regulate the flow of electricity within electronic devices and prevent electromagnetic interference between components. Multilayer ceramic capacitors (185) are essential components in electronic devices because they eliminate noise contained in current and extend the life of electronic devices.

[0043] Smartphones are equipped with more than 800 multilayer ceramic capacitors (185), and products such as LED TVs require 2000 multilayer ceramic capacitors (185).

[0044] Figure 2 is a partial cutaway perspective view illustrating a multilayer ceramic capacitor (185), and Figure 3 is a cross-sectional view of the multilayer ceramic capacitor (185).

[0045] A laminated ceramic capacitor (185) may include a laminated portion (1851) in which an electrode layer (1854) made of multiple layers of metal materials and a ceramic layer (1853) are laminated, and an external electrode (1852) for connecting to a wiring (184) at both ends of the laminated portion (1851).

[0046] The multilayer ceramic capacitor (185) can store electricity between multiple electrode layers (1854), so that the more layers there are, the more electricity can be stored. The multilayer ceramic capacitor (185) is a large-capacity capacitor that can control the flow of current between wires (184). The capacity of the multilayer ceramic capacitor (185) can vary depending on the number and size of the stacked electrode layers (1854). The multilayer ceramic capacitor (185) widely used in display devices is mainly 10uF and 4.7uF.

[0047] The multilayer ceramic capacitor (185) can perform a rectifying function to smooth the flow of electricity within the device and can remove noise, which is an unnecessary interference phenomenon. However, the multilayer ceramic capacitor (185) includes a thin ceramic, so cracks (1855) are likely to occur as shown in FIG. 3. The multilayer ceramic capacitor (185) can be electrically connected by soldering a pair of electrodes (1843, 1844, see FIG. 5) exposed on a circuit board (180) and an external electrode (1852).

[0048] If the circuit board (180) is bent or subjected to external impact, a crack (1855) may occur in the ceramic layer (1853) of the laminated portion (1851). If a crack (1855) occurs in the ceramic layer (1853), the insulation between the electrode layers (1854) may be destroyed, resulting in a short circuit between the electrode layers (1854).

[0049] Fig. 4 is a drawing illustrating a multilayer ceramic capacitor (185) of a conventional electronic device. As illustrated in (a), the multilayer ceramic capacitor (185) may be positioned between a first pattern (1841) and a second pattern (1842). A first electrode (1843) connected to the first pattern (1841) and a second electrode (1844) connected to the second pattern (1842) may be exposed on the surface of a circuit board (180).

[0050] The first electrode (1843) and the second electrode (1844) can be arranged to overlap the first pattern (1841) and the second pattern (1842) as illustrated in FIG. 4. That is, the first electrode (1843) and the second electrode (1844) can be implemented in a form in which a portion of the first pattern (1841) and the second pattern (1842) are exposed on the surface of the circuit board (180).

[0051] The first pattern (1841) may be connected to a power supply unit. A multilayer ceramic capacitor (185) may be added to the first pattern (1841) so that power supplied from the power supply unit can be stably supplied to each component. The multilayer ceramic capacitor (185) connects the first pattern (1841) to ground, and the second pattern (1842) connected to the aforementioned second electrode (1844) may serve as ground.

[0052] If a crack occurs in the multilayer ceramic capacitor (185), the temperature inside the multilayer ceramic capacitor (185) may rise and ignite, which may cause a fire. Even if a fire does not occur, the ignition of the multilayer ceramic capacitor (185) may cause carbonization of the epoxy component of the circuit board (180), and an overcurrent may occur between the power supply and the ground, which may damage electronic components or cause a fire.

[0053] The first pattern (1841), which is a power pattern, has a thickness of 35 μm and can use a 5 mm wide wire. According to the IPC-2221 standard, the maximum allowable current for a 5 mm wire is 9.1 A. Therefore, if a current exceeding this amount flows, the wire may be damaged. If the first pattern (1841) has a thicker width, damage at high currents can be prevented, but the size of the circuit board (180) increases, making it difficult to realistically apply a wide power pattern.

[0054] Therefore, in order to minimize the impact on other components on the circuit board (180) when a crack occurs in the multilayer ceramic capacitor (185), it is necessary to block the flow passing through the multilayer ceramic capacitor (185) before damage to the first pattern (1841) and ignition of the multilayer ceramic capacitor (185).

[0055] Accordingly, the present invention adds a narrow pattern (186) to block current passing through the multilayer ceramic capacitor (185) before ignition when an overcurrent flows due to cracking of the multilayer ceramic capacitor (185).

[0056] Fig. 5 is a diagram illustrating the flow of current when a multilayer ceramic capacitor (185) of an electronic device of the present invention is damaged. The electronic device of the present invention includes a first pattern (1841), a second pattern (1842), a first electrode (1843) connected to the first pattern (1841), a narrow pattern (186) extending from the second pattern (1842), and a second electrode (1844) connected to the narrow pattern (186), and the multilayer ceramic capacitor (185) is connected to the first electrode (1843) and the second electrode (1844).

[0057] Unlike FIG. 4, the second electrode (1844) may not be directly connected to the second pattern (1842) but may be connected through a narrow pattern (186).

[0058] The narrow pattern (186) has a width thinner than the width of the second electrode (1844) and may have a predetermined length. The narrow pattern (186) can be disconnected when an overcurrent flows, thereby preventing ignition from occurring in the multilayer ceramic capacitor (185).

[0059] Fig. 6 is a conceptual diagram for explaining the circuit configuration of the electronic device of the present invention. As illustrated in Fig. 6, power supplied from the power supply unit is supplied to the DCDC converter (187) through the first pattern (1841), and the DCDC converter (187) steps down the voltage so that a low current flows in the section supplied to each electronic component after the output of the DCDC converter. In addition, since the DCDC converter (187) itself has an OCP (Over Voltage Protection) function in its IC, the problem of damage to the multilayer ceramic capacitor (185) after the DCDC does not occur.

[0060] Accordingly, the narrow pattern (186) of the electronic device of the present invention can be applied to a multilayer ceramic capacitor that connects the first pattern connecting the power supply and the DCDC converter (187) and the second pattern (1842) (ground).

[0061] It is necessary to design a pattern width that can break the narrow pattern (186) before ignition of the multilayer ceramic capacitor (185). The melting point of copper is 1085°C, the boiling point of copper is 2562°C, and the ignition temperature of the multilayer ceramic capacitor (185) is approximately 1300°C.

[0062] It is possible to design a narrow pattern (186) in which the temperature of the narrow pattern (186) becomes 2562°C or higher before the temperature of the multilayer ceramic capacitor (185) reaches 1300°C.

[0063] The Joule heat (Q) can be calculated as the product of the square of the current and the resistance and time, and when the multilayer ceramic capacitor (185) cracks, the larger the resistance and current of the narrow pattern (186), the faster the narrow pattern (186) can be broken.

[0064]

[0065] Resistance is inversely proportional to the width of the narrow pattern (186), and the width of the narrow pattern (186) can be determined according to the rated current of the electronic device. When the rated current of the electronic device flows, the temperature of the narrow pattern (186) must rise to the boiling point of copper, which can cause the narrow pattern (186) to break.

[0066] Figure 7 is a table showing the pattern width at which the narrow pattern (186) of the electronic device of the present invention is cut off. It shows the range of the width of the narrow pattern (186) that is cut off when it reaches 2552°C according to the maximum rated current.

[0067] As the rated current increases, the narrow pattern (186) can become thicker. The following explanation is based on an electronic device with a rated current of 10 A. When the copper foil thickness is 35 μm, the narrow pattern (186) breaks when a current of 10 A flows through the pattern width, which has a value of 0.125 to 0.221 mm. If the copper foil thickness is twice that, 70 μm, the pattern width should be thinner by about half.

[0068] Since a circuit board (180) of 35 μm copper foil is generally used, the following description is based on 35 μm copper foil. Accordingly, a narrow pattern (186) of 0.125 mm or less is 4.375x10 -3 It can be understood as having the same meaning as the narrow pattern (186) of cross-sectional area of ​​㎣.

[0069] The narrow pattern (186) can be designed to have a width of 0.1 mm so that the narrow pattern (186) can be short-circuited before reaching the rated current. As described above, the width of the narrow pattern (186) can vary depending on the rated current and the thickness of the copper foil.

[0070] FIG. 8 is a diagram showing the resistance and inductance according to the size of the narrow pattern (186) of the electronic device of the present invention and the equivalent circuit of the laminated ceramic capacitor (185) according to the addition of the narrow pattern (186).

[0071] The multilayer ceramic capacitor (185) has not only a capacitor value but also resistance (ESR) and inductance (ESL) components when depicted in a circuit diagram. Inductance reactance (X L ) is ωL (ω is the angular frequency 2πf), and its value increases as the frequency increases. The inductance component of the multilayer ceramic capacitor (185) is very small, so an inductance reactance value of 1 nH or more can be obtained at a high frequency of 3 to 4 MHz or more.

[0072] Since the multilayer ceramic capacitor (185) of the present invention operates in a frequency band of 1 NMHz or less, the inductance component of the multilayer ceramic capacitor (185) does not affect the overall circuit configuration.

[0073] When a narrow pattern (186) is connected to a multilayer ceramic capacitor (185), the resistance component and inductance component of the narrow pattern (186) affect the impedance value of the multilayer ceramic capacitor (185). The resistance of the narrow pattern (186) can be referred to as parasitic resistance, and the inductance of the narrow pattern (186) can be referred to as parasitic inductance. The sum of the resistance and parasitic resistance of the multilayer ceramic capacitor (185) becomes the integrated resistance of the multilayer ceramic capacitor (185) to which the narrow pattern (186) is added, and the sum of the inductance of the multilayer ceramic capacitor (185) and the parasitic inductance (Lp) becomes the integrated inductance.

[0074] The integrated impedance (Z) of the narrow pattern (186) in the multilayer ceramic capacitor (185) can be derived through the following values.

[0075]

[0076] R=ESR+Rp, L=ESL+Lp≒Lp C=capacitance of the red ceramic capacitor

[0077] Since the overall resistance changes significantly due to the addition of parasitic resistance, the overall impedance changes, so the size of the parasitic resistance may be smaller than the resistance (ESR) of the multilayer ceramic capacitor (185). Preferably, it may have a value of 50%.

[0078] Since the reactance of the multilayer ceramic capacitor (185) is very small, the integrated reactance (L) becomes substantially equal to the parasitic reactance value (Lp). As the parasitic reactance (Lp) is added, an inductive reactance value (XL = ωL) reactance value is generated, which causes a decrease in the capacitive reactance value (Xc) of the multilayer ceramic capacitor (185), thereby reducing the integrated reactance (X = ωL-1 / (ωC)).

[0079] FIG. 9 is a table showing the change rate of resistance and inductance according to the size of the narrow pattern (186) of the electronic device of the present invention and the reactance of the multilayer ceramic capacitor (185) according to the addition of the narrow pattern (186).

[0080] When a narrow pattern (186) is added to a multilayer ceramic capacitor (185) having a capacity of 10 μF at a frequency of 700 kHz, if the reduction rate of reactance (X) is large due to the addition of a parasitic inductance (Lp) value, the performance of the multilayer ceramic capacitor (185) in a normal operating state is affected. Accordingly, the length of the narrow pattern (186) can be determined so that the reduction rate of reactance (X) is 15% or less.

[0081] Since 1.25 mm shows a reduction rate of 16%, the length of the narrow pattern (185) can have a length less than 1.25 mm.

[0082] As seen in Fig. 7, the narrow pattern (186) having a width of 0.1 mm has a small reactance reduction rate due to parasitic inductance (Lp) when the length is 1 mm or less, and the size of the resistance also becomes smaller as the length becomes shorter, so the size of the parasitic resistance can also have a small value.

[0083] Figure 10 is a table showing the amount of reactance reduction according to the presence or absence of a narrow pattern (186) and the capacity of a laminated ceramic capacitor (185).

[0084] The amount of reactance reduction according to the capacitance of the multilayer ceramic capacitor (185) is shown depending on whether a narrow pattern (186) with a width of 0.1 mm and a length of 1 mm is added. The table in Fig. 9 shows the capacitive reactance (X) as a value for a multilayer ceramic capacitor (185) of 10 μF. c ) is 0.22736 and the inductive reactance (X) due to the addition of the narrow pattern (186) l ) the reactance decreases by 12.5%.

[0085] For smaller capacitances, the capacitive reactance (X) c ) is relatively larger, so the reactance reduction is smaller, and the performance of the multilayer ceramic capacitor (185) can be maintained. Therefore, a narrow pattern (186) with a width of 0.1 mm and a length of 1 mm can be added to a multilayer ceramic capacitor (185) of a different capacity.

[0086] Fig. 11 is a graph illustrating the hiccup mode that occurs when a multilayer ceramic capacitor breaks and the temperature change of the multilayer ceramic capacitor (185). When the resistance is small, the impact on the performance of the multilayer ceramic capacitor (185) is small, but it may take more time for the narrow pattern (186) to break. As seen in Equation 1, when the R value decreases, the t value must relatively increase.

[0087] When a narrow pattern (186) is added, the multilayer ceramic capacitor (185) may be short-circuited before ignition, but smoke may be generated in the multilayer ceramic capacitor (185) due to the hiccup mode. The hiccup mode is a form of overcurrent protection in a power supply, which means that when an overcurrent is detected, the power supply repeats the operation of turning the power off and on at a predetermined cycle. According to the hiccup mode, when power is applied, an overcurrent passes through the multilayer ceramic capacitor (185), the internal temperature rises, and smoke may be generated accordingly.

[0088] The narrow pattern (186) is disconnected before the multilayer ceramic capacitor (185) reaches the ignition temperature, but the disconnection time may vary depending on its width and length. Fig. 12 is a table showing the ignition and hiccup current generation of the multilayer ceramic capacitor according to the specifications of the narrow pattern (186) added to the 10 μF multilayer ceramic capacitor (185).

[0089] The hiccup cycle of the power supply unit of this embodiment supplies power in a cycle of 850 ms, with On 135 ms and Off 715 ms. Tests were conducted on narrow patterns (186) having specifications with a smaller resistance value than those having a width of 0.1 mm and a length of 1 mm. It can be confirmed that all of the narrow patterns, except for the narrow patterns having a width of 0.1 mm and a length of 1 mm, did not break before the hiccup current was generated.

[0090] That is, smoke may occur several times due to the hiccup current before the current is cut off due to a short circuit. To avoid smoke generation due to the hiccup current, the length of the narrow pattern (186) must be set so that the narrow pattern (186) is shorted before the hiccup current occurs.

[0091] Therefore, when the narrow pattern (186) has a width of 0.1 mm and a length of 1 mm, it can be short-circuited before the hiccup current is generated while minimizing the impact on the performance of the multilayer ceramic capacitor (185).

[0092] Fig. 13 is a drawing showing the arrangement of the narrow pattern (186) of the electronic device of the present invention and the second pattern (1842). Since the narrow pattern of the present invention has a length of 1 mm, in order to implement it by changing the design in the existing circuit diagram, the shape of the second pattern (ground) (1842) can be configured as a concave shape as shown in Fig. 13 so as to be spaced apart from the second electrode (1844) by a predetermined distance.

[0093] A second pattern (1842) can be connected to a narrow pattern (186) on one side of the second electrode (1844). The connection direction of the narrow pattern (186) can be in any direction regardless of the arrangement of the multilayer ceramic capacitor (185), and the portion where the narrow pattern (186) is not connected can be configured so that the gap between the second electrode (1844) and the second pattern (1842) is 0.3 mm or more.

[0094] When designing a new circuit diagram, the second pattern (1842) can also be configured in a form that does not surround the second electrode (1844), as in (d) of Fig. 13.

[0095] As seen above, the electronic device of the present invention can protect the electronic device by not igniting even if a crack occurs in the multilayer ceramic capacitor (185).

[0096] In addition, the electronic device of the present invention can solve a failure by partial repair by preventing damage to the entire circuit board (180).

[0097] In addition, the electronic device of the present invention can maintain the function of the multilayer ceramic capacitor (185) even if a narrow pattern (186) is added.

[0098] The above detailed description should not be construed as limiting in any respect and should be considered illustrative only. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are intended to be included within the scope of the present invention.

[0099] With respect to various embodiments for implementing the present invention, duplicate descriptions are omitted as they have been described above in the previous table of contents, Best Mode for Carrying Out the Invention.

[0100] The present invention is applicable to circuit boards and electronic devices in various fields, and thus its industrial applicability is recognized.

Claims

1. First pattern; A second pattern arranged adjacent to the first pattern; A narrow pattern extended from the second pattern above; A first electrode overlapping the first pattern; A second electrode connected to the end of the above narrow pattern; A circuit board characterized by including a laminated ceramic capacitor that electrically connects the first pattern and the second pattern by connecting the first electrode and the second electrode.

2. In paragraph 1, A circuit board characterized in that the resistance of the narrow pattern has a value less than 50% of the resistance of the multilayer ceramic capacitor.

3. In paragraph 1, The total reactance (X) value of the above narrow pattern and the above multilayer ceramic capacitor is A circuit board characterized in that the reactance value of the above-mentioned laminated ceramic capacitor is 85% or more.

4. In paragraph 1, A circuit board characterized in that the above narrow pattern has a length of more than 0.75 mm and less than 1.25 mm.

5. In paragraph 1, The above narrow pattern is A circuit board characterized by having a width of 0.125 mm or less.

6. In paragraph 1, The above narrow pattern is The cross section perpendicular to the longitudinal direction is 4.375x10 -3 A circuit board characterized by having a value of ㎣ or less.

7. In paragraph 1, A circuit board characterized in that the second pattern is ground.

8. In paragraph 1, The second pattern is inserted in a T-shape surrounding three sides of the second electrode and includes a recessed portion including a first side from which the narrow pattern is extended, The first side has a gap corresponding to the length of the second electrode and the narrow pattern, A circuit board characterized in that the second side and the third side of the recessed portion are spaced apart from the second electrode by a gap of 0.3 mm or more.

9. In paragraph 1, A circuit board characterized in that the first pattern is located between the power supply unit and the DCDC converter.

10. In paragraph 1, It includes a power supply unit that applies power to the first pattern and switches to hiccup mode that periodically turns the power ON / OFF when overcurrent is detected. The above narrow pattern is A circuit board characterized in that it is short-circuited within one cycle of the above hiccup mode.

11. In paragraph 1, A circuit board characterized in that the capacity of the above-mentioned laminated ceramic capacitor is 10uF or less.

12. A circuit board comprising one of the circuit boards of clauses 1 to 11. Electronic devices.

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