Electronic circuit comprising metallic ion migration reduction circuit

Abstract

An electronic circuit according to one embodiment of the present invention comprises: an integrated circuit; and a metallic ion migration reduction circuit connected to the integrated circuit, wherein the metallic ion migration reduction circuit includes a pull-up resistor and a pull-down resistor, wherein the pull-up resistor and the pull-down resistor are connected in series and are arranged such that the size of the pull-down resistor is larger than the size of the pull-up resistor, thereby reducing the occurrence of metallic ion migration.

Description

Electronic circuit including a metal ion migration reduction circuit

[0001] The present invention relates to a metal ion migration reduction circuit, and to a method for setting the size of a pull-up resistor and a pull-down resistor.

[0002] Printed circuit boards (PCBs) electrically connect metal components and are a core component of electronic devices. These PCBs can be used in external electronic devices, such as portable terminals, metal components in automobiles, industrial equipment, and military equipment, making them susceptible to exposure to the external environment.

[0003] When printed circuit boards are exposed to external environments, particularly high temperatures and high humidity, metal ion migration can occur, which can reduce the reliability of the printed circuit board. Metal ion migration occurs when a voltage is applied to two electrically insulated metal electrodes, causing electrochemical instability and the growth of conductive metal between the two electrodes, resulting in an electrical short circuit.

[0004] Moreover, as metal components become lighter, thinner, and more highly integrated, the line width of circuit patterns on printed circuit boards and the spacing between circuit patterns are gradually decreasing, which causes problems such as condensation due to high temperature and high humidity environments, which causes short circuits between electronic circuits due to metal ion migration, and thus causes fatal failures of electronic products.

[0005] Accordingly, one embodiment of the present invention is to provide an electronic circuit including a metal ion migration reduction circuit for resolving the metal ion migration phenomenon.

[0006] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0007] In order to achieve the above object, an electronic circuit according to one embodiment of the present invention includes an integrated circuit; and a metal ion migration reduction circuit connected to the integrated circuit, wherein the metal ion migration reduction circuit includes a pull-up resistor and a pull-down resistor, wherein the pull-up resistor and the pull-down resistor are connected in series, and the size of the pull-down resistor is arranged to be larger than the size of the pull-up resistor, thereby reducing the occurrence of metal ion migration.

[0008] In one embodiment, the metal ion migration reduction circuit has a positive electrode of the pull-up resistor connected to a voltage source, a negative electrode of the pull-up resistor connected to the positive electrode of the pull-down resistor, and a negative electrode of the pull-down resistor connected to ground.

[0009] In one embodiment, the metal ion migration reduction circuit has a length that is the sum of the size of the pull-up resistor and the size of the pull-down resistor, and is greater than the maximum diameter of a water droplet generated due to condensation.

[0010] In one embodiment, the metal ion migration reduction circuit is configured such that the size of the pull-down resistor is set such that only a portion of the pull-up resistor is included in the water droplet generated by the condensation.

[0011] In one embodiment, the metal ion migration reduction circuit delays the metal ion migration generation rate by lowering the bias voltage applied to both ends of the water droplets generated by the condensation.

[0012] Specific details of other embodiments are included in the detailed description and drawings.

[0013] According to an embodiment of the present invention, one or more of the following effects are provided.

[0014] The electronic circuit of the present invention has a metal ion migration reduction circuit arranged so that the size of the pull-down resistor is larger than that of the pull-up resistor, thereby preventing short circuits between circuit patterns, thereby realizing high density and ensuring reliability at the same time.

[0015] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0016] FIG. 1 is a drawing for explaining a situation in which condensation occurs in a display device according to one embodiment of the present invention.

[0017] Figure 2 is a drawing for explaining a situation in which metal ion migration occurs due to condensation according to a temporary example of the present invention.

[0018] Figures 3 to 6 are drawings for explaining the metal ion migration phenomenon of a metal part according to a temporary example of the present invention.

[0019] FIG. 7 and FIG. 8 are drawings for explaining a metal ion migration reduction circuit corresponding to the size of a metal part according to one embodiment of the present invention.

[0020] FIG. 9 is a drawing for explaining an electronic circuit including a metal ion migration reduction circuit according to one embodiment of the present invention.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0025] 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.

[0026] FIG. 1 is a drawing for explaining a situation in which condensation occurs in a display device according to one embodiment of the present invention.

[0027] As illustrated in Fig. 1, when the ambient temperature around a display device (hereinafter, TV) rises and the TV is turned off, the temperature of the atmosphere containing moisture may drop below the dew point due to the temperature difference between the TV and the atmosphere, causing moisture contained in the atmosphere to form water droplets (200) on the surface of a printed circuit board (PCB) (100), resulting in condensation. The printed circuit board (100) may be placed vertically on the floor.

[0028] Water droplets (200) generated by condensation may initially be small droplets with a diameter of less than 1 μm, and multiple nuclei may be generated. When the generated water droplets (200) grow and at least one or more droplets combine, they may reach a size of several mm and flow down the surface of the printed circuit board (100).

[0029] For example, the size of the water droplets (200) to flow down by gravity may be 2.7 mm or more in diameter. That is, if the water droplets (200) generated by condensation have a diameter of 2.7 mm or more through growth and combination, they may flow down in the direction of gravity along the printed circuit board (100).

[0030] For example, condensation may occur when the TV is turned off and the ambient temperature cools down and then rises again.

[0031] For example, condensation can form primarily on metal surfaces, such as the TV's cover bottom and heat sink. This means that condensation can form on the PCB, where the temperature of the material inside the TV is lower than the dew point of the surrounding air.

[0032] Figure 2 is a drawing for explaining a situation in which metal ion migration occurs due to condensation according to a temporary example of the present invention.

[0033] Referring to FIG. 2, metal ion migration occurring on a printed circuit board (100) placed inside a TV according to the present invention will be described.

[0034] In hot and humid areas such as near the coast and near the equator, the air temperature around the TV rises, and when the TV is turned off, condensation (300) may occur on the printed circuit board (100) due to the temperature difference between the TV and the air.

[0035] For example, if the area where the TV is located has a humidity of over 90% and an air temperature of over 20 degrees, and the air temperature rises to about 60 degrees, condensation (300) may occur when the air temperature is 25 degrees.

[0036] Afterwards, when the TV is turned on, bias power may be applied to the printed circuit board (100). Metal parts may be located in water droplets generated by condensation on the printed circuit board (100), and oxidation and reduction phenomena may occur due to the bias power.

[0037] Accordingly, among the metal parts located inside the water droplet, the oxidized metal ions at the (+) anode move to the (-) cathode due to the bias voltage, and due to the reduction reaction at the (-) cathode, a metal material deposition phenomenon may occur on the surface of the metal part. In addition, the deposited metal may be adsorbed on the surface of the metal part.

[0038] Afterwards, when the ambient temperature drops while the TV is turned on, the printed circuit board (100) dries and water droplets formed due to condensation can be removed.

[0039] Afterwards, if condensation / drying is repeated due to changes in TV and air temperature, continuous deposition phenomenon may occur on the (-) cathode of the metal part, and metal ion migration may occur in which plating material continuously accumulates on the surface of the part.

[0040] If metal ion migration occurs in this way, the problem of the two ends of the metal part being short-circuited due to the plating body may occur.

[0041] Figures 3 to 6 are drawings for explaining the metal ion migration phenomenon of a metal part according to a temporary example of the present invention.

[0042] Referring to FIG. 3, a metal ion migration phenomenon may occur when a metal component (400) is placed within a water droplet (200) generated by condensation according to one embodiment of the present invention. In one embodiment of the present invention, the metal component is described as being made of tin (Sn), but the metal component is not limited thereto.

[0043] The metal (Sn+) oxidized and ionized at the (+) anode of the metal component (400) located inside the water droplet moves to the (-) cathode due to the bias voltage, and the metal (Sn+) ionized at the (-) cathode of the metal component (400) is reduced so that a metal material (Sn) can be deposited on the surface of the metal component (400).

[0044] Referring to FIGS. 4 to 6, according to one embodiment of the present invention, a metal ion migration phenomenon may occur due to two metal parts (500, 600) connected in series and water droplets (200) generated by condensation.

[0045] At this time, the (+) positive pole of the first metal component (500) can be connected to a power source, the (-) negative pole of the first metal component (500) can be connected to the (+) positive pole of the second metal component (600), and the (-) negative pole of the second metal component (600) can be connected to ground (GND).

[0046] At this time, the higher the bias voltage applied to the water droplet containing at least one metal component (500, 600), the higher the movement speed of the ions, which may increase the risk of defects occurring due to the metal ion migration phenomenon.

[0047] In addition, the reduction rate of the metal ion migration phenomenon can be changed by the electron supply rate and electron supply amount. Therefore, the reduction rate of the metal ion migration phenomenon increases as the electron supply becomes smoother due to the bias voltage applied to the droplet containing at least one metal component (500, 600), which may increase the risk of defects occurring due to the metal ion migration phenomenon.

[0048] Referring to FIG. 4, according to the first embodiment of the present invention, a first metal part (500) and a second metal part (600) can be placed inside a water droplet.

[0049] Due to the metal ion migration phenomenon, the metal (Sn) oxidized and ionized at the (+) anode of the first metal component (500) moves to the (-) cathode of the second metal component (600) due to the bias voltage, and the metal (Sn+) ionized at the (-) cathode of the second metal component (600) is reduced, so that a metal material (Sn) can be deposited on the surface of the second metal component (600).

[0050] At this time, the rate of oxidation at the (+) anode of the first metal component (500) may be the same as the rate of reduction of ionized metals (Sn+) at the (-) cathode of the second metal component (600).

[0051] Referring to FIG. 5, a second metal component (600) can be placed inside a water droplet according to a second embodiment of the present invention.

[0052] Due to the metal ion migration phenomenon, the metal (Sn) oxidized and ionized at the (+) anode of the second metal component (600) moves to the (-) cathode of the second metal component (600) due to the bias voltage, and the metal (Sn+) ionized at the (-) cathode of the second metal component (600) is reduced, so that a metal material (Sn) can be deposited on the surface of the second metal component (600).

[0053] At this time, the rate of oxidation at the (+) anode of the second metal component (600) may be the same as the rate of reduction of ionized metals (Sn+) at the (-) cathode of the second metal component (600).

[0054] Referring to FIG. 6, a first metal component (500) can be placed inside a water droplet according to a third embodiment of the present invention.

[0055] Due to the metal ion migration phenomenon, the metal (Sn) oxidized and ionized at the (+) anode of the first metal component (500) moves to the (-) cathode of the first metal component (500) due to the bias voltage, and the metal (Sn+) ionized at the (-) cathode of the first metal component (500) is reduced, so that a metal material (Sn) can be deposited on the surface of the first metal component (500).

[0056] At this time, the (-) cathode of the first metal component (500) may have a reduced electron supply due to resistance, so that the rate at which ionized metals (Sn+) are reduced may be slower than the rate at which they are oxidized.

[0057] Therefore, since the bias voltage applied to the first metal component (500) and the second metal component (600) by the first embodiment is higher than the bias voltage applied by the second or third embodiment, the risk of defects occurring due to the metal ion migration phenomenon in the first embodiment may be higher than in the second or third embodiment.

[0058] And, since the reduction speed of the first metal component (500) according to the third embodiment is slower than the reduction speed of the second metal component (500) according to the second embodiment, the risk of defects occurring due to the metal ion migration phenomenon in the third embodiment may be lower than in the second embodiment.

[0059] That is, the risk of defects occurring due to metal ion migration according to the first to third embodiments may increase in the order of the first embodiment, the second embodiment, and the third embodiment.

[0060] FIG. 7 and FIG. 8 are drawings for explaining a metal ion migration reduction circuit corresponding to the size of a metal part according to one embodiment of the present invention.

[0061] A metal ion migration reduction circuit according to one embodiment of the present invention may include a voltage source (VDD), a pull-up resistor (700), and a pull-down resistor (800). The (+) anode of the pull-up resistor (700) may be connected to the voltage source (VDD), the (-) cathode of the pull-up resistor (700) may be connected to the (+) anode of the pull-down resistor (800), and the (-) cathode of the pull-down resistor (800) may be connected to ground (GND).

[0062] Referring to Fig. 8, the conventional metal ion migration reduction circuit can use components of the same size for the pull-up resistor (700) and the pull-down resistor (800).

[0063] For example, if the pull-up resistor (700) and the pull-down resistor (800) are 1005 size resistors, the length of each resistor may be 1 mm. Therefore, the combined length of the wires connecting the pull-up resistor (700) and the pull-down resistor (800) may be 2.2 mm. In addition, since the maximum diameter of water droplets generated due to condensation is 2.7 mm, both the pull-up resistor (700) and the pull-down resistor (800) may be submerged by water droplets.

[0064] That is, in the conventional metal ion migration reduction circuit, if the pull-up resistor (700) and the pull-down resistor (800) use parts of the same size, there is a problem in that when water droplets occur due to condensation, both the pull-up resistor (700) and the pull-down resistor (800) become submerged, increasing the risk of defects occurring due to the metal ion migration phenomenon.

[0065] To solve this, as illustrated in FIG. 8, the metal ion migration reduction circuit of the present invention may use components of different sizes for the pull-up resistor (700) and the pull-down resistor (800). In this case, the size of the pull-down resistor (800) may be larger than the size of the pull-up resistor (700).

[0066] For example, the pull-up resistor (700) may be a 1005 size resistor, and the pull-down resistor (800) may be a 1608 size resistor. At this time, the length of the pull-up resistor (700) is 1 mm, and the length of the pull-down resistor (800) is 1.6 mm, so the combined length of the wires connecting the pull-up resistor (700) and the pull-down resistor (800) may be 2.85 mm. In addition, since the maximum diameter of water droplets generated due to condensation is 2.7 mm, only the pull-down resistor (800) may be submerged by the water droplets.

[0067] For example, the pull-up resistor (700) may be a 1608-sized resistor, and the pull-down resistor (800) may be a 1608-sized resistor. At this time, the length of the pull-up resistor (700) is 1.6 mm, and the length of the pull-down resistor (800) is 1.6 mm, so the combined length of the wires connecting the pull-up resistor (700) and the pull-down resistor (800) may be 3.5 mm.

[0068] That is, the metal ion migration reduction circuit according to the present invention can use components of different sizes so that the size of the pull-down resistor (800) is larger than the size of the pull-up resistor (700). As a result, when water droplets are generated due to condensation, only one pull-down resistor (800) can be submerged, thereby reducing the bias voltage applied across the water droplets. Accordingly, when the bias voltage is reduced, the speed of metal ion migration generation can be delayed, thereby reducing the risk of defects occurring due to the metal ion migration phenomenon.

[0069] FIG. 9 is a drawing for explaining an electronic circuit including a metal ion migration reduction circuit according to one embodiment of the present invention.

[0070] Referring to FIG. 9, the electronic circuit may include an integrated circuit (IC) and a metal ion migration reduction circuit. The metal ion migration reduction circuit may be configured with a pull-up resistor and a pull-down resistor connected to a feedback pin (FB) of the integrated circuit (IC).

[0071] The size of a typical resistive component placed within an electronic circuit can be configured so as not to exceed its power specification. The power specification can be determined by measuring the voltage across the resistor.

[0072] These 1005 size resistors are used in electronic circuits, and if a power greater than the power specification of the 1005 size resistor is required, a 1608 size resistor can be used.

[0073] The metal ion migration reduction circuit according to the present invention can be configured so as not to exceed the power specification by using a 1005 size resistor, but can apply a 1608 size resistor to delay the occurrence of metal ion migration.

[0074] Therefore, the metal ion migration reduction circuit according to the present invention can be configured with pull-up resistors and pull-down resistors connected in series with different sizes.

[0075] Here, the pull-up resistor (R1) can be configured with a size of 1005, and the pull-down resistor (R2) can be configured with a size of 1608. That is, only the pull-down resistor R2502 can be configured with a different size.

[0076] Due to this, the metal ion migration reduction circuit can improve the reliability of the electronic circuit by artificially changing the resistance at the pull-down position to a large-sized resistance, thereby preventing the pull-up resistor and the pull-down resistor from being simultaneously submerged due to condensation, thereby lowering the bias voltage applied to both ends of the water droplet, and delaying the speed of metal ion migration generation.

[0077] The detailed description of the preferred embodiments of the present invention disclosed above has been provided to enable those skilled in the art to implement and practice the present invention. While the above description has been made with reference to preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the scope of the present invention. For example, those skilled in the art can utilize the individual components described in the above-described embodiments in combination with each other.

[0078] Accordingly, the present invention is not intended to be limited to the embodiments shown herein, but is intended to encompass the optimum scope consistent with the principles and novel features disclosed herein.

[0079] Various embodiments for implementing the present invention have been described in detail in the previous table of contents.

[0080] The present invention is applicable to technologies related to electronic circuits, and thus its industrial applicability is recognized.

Claims

1. As an electronic circuit, Integrated circuits; and A metal ion migration reduction circuit connected to the above integrated circuit is included, The above metal ion migration reduction circuit It includes a pull-up resistor and a pull-down resistor, wherein the pull-up resistor and the pull-down resistor are connected in series, The size of the pull-down resistor is arranged to be larger than the size of the pull-up resistor, thereby reducing the occurrence of metal ion migration. Electronic circuit.

2. In paragraph 1, The above metal ion migration reduction circuit The positive pole of the pull-up resistor is connected to a voltage source, the negative pole of the pull-up resistor is connected to the positive pole of the pull-down resistor, and the negative pole of the pull-down resistor is connected to ground. Electronic circuit.

3. In paragraph 2, The above metal ion migration reduction circuit The combined length of the size of the pull-up resistor and the size of the pull-down resistor is larger than the maximum diameter of the water droplet generated due to condensation. Electronic circuit.

4. In paragraph 3, The above metal ion migration reduction circuit Characterized in that the size of the pull-down resistor is set so that only a portion of the pull-up resistor is included in the water droplets generated by the condensation. Electronic circuit.

5. In paragraph 4, The above metal ion migration reduction circuit It is characterized by delaying the speed of metal ion migration generation by lowering the bias voltage applied to both ends of the water droplets generated by the above condensation. Electronic circuit.

6. A printed circuit board characterized by including an electronic circuit according to any one of claims 1 to 5.

7. A display device characterized by including an electronic circuit according to any one of claims 1 to 5.

Images