Inspection system, inspection method, and manufacturing method

Abstract

To supply a desired amount of inrush current to a capacitor.SOLUTION: An inspection system 90 includes a first voltage application circuit 91, a second voltage application circuit 92, and a control circuit 93. The first voltage application circuit 91 applies a first voltage V1 to a capacitor 1. The second voltage application circuit 92 applies a second voltage V2 larger than the first voltage V1 to the capacitor 1. The control circuit 93 controls the first voltage application circuit 91 and the second voltage application circuit 92 to supply an inrush current to the capacitor 1 by applying the first voltage V1 and the second voltage V2 to the capacitor 1 to charge the capacitor 1. The control circuit 93 controls the first voltage application circuit 91 and the second voltage application circuit 92 to stop the application of the second voltage V2 to the capacitor 1 before the voltage across the capacitor 1 reaches the first voltage V1 due to the supply of the inrush current.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to an inspection system, an inspection method, and a manufacturing method, and more particularly, to an inspection system and an inspection method for inspecting capacitors and a manufacturing method for capacitors. [Background technology]

[0002] Patent Document 1 discloses an inspection device for electrolytic capacitors. The inspection device in Patent Document 1 includes an inrush current supply capacitor that is arranged in parallel with a test electrolytic capacitor via a discharge resistor, and a power source that charges the inrush current supply capacitor.

[0003] When the inrush current supply capacitor is charged and a switch between the inrush current supply capacitor and the test electrolytic capacitor is turned on, current can be made to flow all at once from the inrush current supply capacitor to the test electrolytic capacitor via the discharge resistor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-348990 A Summary of the Invention [Problem to be solved by the invention]

[0005] The inspection device described in Patent Document 1 may not be able to supply an inrush current of a desired magnitude to the electrolytic capacitor under test.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and an object of the present disclosure is to provide an inspection system, an inspection method, and a manufacturing method that are capable of supplying an inrush current of a desired magnitude to a capacitor. [Means for solving the problem]

[0007] An inspection system according to an aspect of the present disclosure includes a first voltage application circuit, a second voltage application circuit, and a control circuit. The first voltage application circuit applies a first voltage to a capacitor under test. The second voltage application circuit applies a second voltage higher than the first voltage to the capacitor under test. The control circuit controls the first voltage application circuit and the second voltage application circuit to apply the first voltage and the second voltage to the capacitor under test, thereby supplying an inrush current to the capacitor under test to charge the capacitor under test. The control circuit also controls the first voltage application circuit and the second voltage application circuit to stop application of the second voltage to the capacitor under test before the voltage across the capacitor under test reaches the first voltage due to the supply of the inrush current. The first voltage application circuit includes a first switch that switches on and off application of the first voltage to the capacitor under test. The second voltage application circuit includes a second switch that switches on and off application of the second voltage to the capacitor under test. The control circuit applies the first voltage and the second voltage to the capacitor under test by turning on the first switch and the second switch. The control circuit turns off the second switch before the voltage across the capacitor under test reaches the first voltage. The second switch includes a transistor. When the control circuit turns on the first switch, a voltage supply source of the first voltage is connected to the base or gate of the transistor, and when the control circuit turns on the first switch, the transistor is turned on by a voltage corresponding to the difference between the output voltage from the voltage supply source and the voltage across the capacitor under test.

[0008] An inspection method according to an aspect of the present disclosure includes: applying a first voltage and a second voltage higher than the first voltage to a capacitor under test, thereby supplying an inrush current to the capacitor under test to charge the capacitor under test; and stopping the application of the second voltage to the capacitor under test before a voltage across the capacitor under test reaches the first voltage due to the supply of the inrush current. The The first voltage application circuit includes a first switch for switching on and off the application of the first voltage to the test object capacitor. TheThe second voltage application circuit includes a second switch that switches on and off application of the second voltage to the capacitor under test. Charging the capacitor under test includes applying the first voltage and the second voltage to the capacitor under test by turning on the first switch and the second switch. Stopping application of the second voltage to the capacitor under test includes turning off the second switch before the voltage across the capacitor under test reaches the first voltage. The second switch includes a transistor. When the first switch is turned on, a voltage supply source of the first voltage is connected to a base or gate of the transistor. When the first switch is turned on, the transistor is turned on by a voltage corresponding to the difference between the output voltage from the voltage supply source and the voltage across the capacitor under test.

[0009] A manufacturing method according to an aspect of the present disclosure includes manufacturing a capacitor and inspecting the capacitor, the inspecting step being performed based on the inspection method described above. Effect of the Invention

[0010] The present disclosure has the advantage of being able to supply a desired amount of in-rush current to a capacitor. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a configuration diagram of an inspection system according to an embodiment. [Diagram 2] FIG. 2 is a time chart for explaining the operation of the above inspection system. [Diagram 3] FIG. 3 is a waveform diagram showing the behavior of the voltage and current of a capacitor when a non-defective capacitor is inspected by the inspection system. [Figure 4] FIG. 4 is a waveform diagram showing the behavior of the voltage and current of a capacitor when a defective capacitor is inspected by the inspection system. [Diagram 5] FIG. 5 is a configuration diagram of a specific example of the above inspection system. [Figure 6] FIG. 6 is a time chart for explaining the operation of the above inspection system. [Figure 7] FIG. 7 is a perspective view of a capacitor to be inspected by the inspection system. [Figure 8] FIG. 8 is a partial cross-sectional view of the capacitor as viewed obliquely. [Figure 9] FIG. 9 is a cross-sectional view of the capacitor. [Figure 10] FIG. 10 is an exploded perspective view of a capacitor element included in the capacitor. [Figure 11] FIG. 11 is an equivalent circuit diagram of the capacitor of the above embodiment. [Figure 12] FIG. 12 is a flowchart showing a procedure of a capacitor inspection method performed using the above inspection system. [Figure 13] FIG. 13 is a flow chart showing a procedure of a capacitor manufacturing method performed using the above inspection system. [Figure 14] FIG. 14 is a configuration diagram of an inspection system of a comparative example. [Figure 15] FIG. 15 is a configuration diagram of an inspection system according to a modified example. [Figure 16] FIG. 16 is a configuration diagram of a specific example of the above inspection system. [Figure 17] FIG. 17 is a time chart for explaining the operation of the above inspection system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An inspection system 90 according to an embodiment will be described below with reference to the accompanying drawings. However, the following embodiments are merely a part of various embodiments of the present disclosure. The following embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. In addition, each figure described in the following embodiments is a schematic diagram, and the size and thickness ratios of each component in the figure do not necessarily reflect the actual dimensional ratios.

[0013] (1) Overview The inspection system 90 of this embodiment is an apparatus for inspecting a capacitor (a capacitor to be inspected) 1.

[0014] As shown in FIG. 1, the inspection system 90 includes a first voltage application circuit 91, a second voltage application circuit 92, and a control circuit 93.

[0015] The first voltage application circuit 91 applies a first voltage V1 to the capacitor 1. The magnitude of the first voltage V1 is a value that coincides with the rated voltage of the capacitor 1, for example.

[0016] The second voltage application circuit 92 applies a second voltage V2 to the capacitor 1. The second voltage V2 is greater than the first voltage V1.

[0017] The control circuit 93 controls the first voltage application circuit 91 and the second voltage application circuit 92. The control circuit 93 controls the first voltage application circuit 91 and the second voltage application circuit 92 so as to apply a first voltage V1 and a second voltage V2 to the capacitor 1, thereby supplying an inrush current to the capacitor 1 and charging the capacitor 1. The control circuit 93 controls the first voltage application circuit 91 and the second voltage application circuit 92 so as to stop application of the second voltage V2 to the capacitor 1 before the voltage across the capacitor 1 reaches the first voltage V1 due to the supply of the inrush current.

[0018] In the inspection system 90, first, a first voltage V1 and a second voltage V2 are applied across the discharged capacitor 1. As a result, a current (inrush current) determined by the second voltage V2 (>first voltage V1) is supplied to the capacitor 1. That is, the inspection system 90 of this embodiment can supply an inrush current of a desired magnitude determined by the second voltage V2 to the capacitor 1. The inrush current supplied from the second voltage application circuit 92 to the capacitor 1 is larger than the current that can be supplied from the first voltage application circuit 91 to the capacitor 1. The capacitor 1 is charged by being supplied with the inrush current.

[0019] Furthermore, in the inspection system 90 of this embodiment, the application of the second voltage V2 to the capacitor 1 is stopped before the voltage across the capacitor 1 reaches the first voltage V1. Therefore, in the inspection system 90 of this embodiment, it is possible to prevent a voltage exceeding the first voltage V1 from being applied to the capacitor 1 while being able to supply an inrush current of a desired magnitude.

[0020] (2)Details The inspection system 90 of this embodiment will be described in more detail below with reference to FIGS.

[0021] (2.1) Capacitor First, a capacitor (test target capacitor) 1 that is an object of testing by the testing system 90 of this embodiment will be described with reference to FIGS.

[0022] The capacitor 1 is a surface mount type or lead type electrolytic capacitor, and may be an electrolytic capacitor using a conductive polymer or an electrolytic solution as the electrolyte, or may be a so-called hybrid type electrolytic capacitor that combines a conductive polymer with an electrolytic solution. Of these, the capacitor 1 is preferably a hybrid type electrolytic capacitor that is used in vehicles and requires high reliability. Here, the surface mount type hybrid type capacitor 1 will be described as an example.

[0023] Fig. 7 is a perspective view of the capacitor 1. Fig. 8 is a partial cross-sectional view of the capacitor 1 seen from an oblique angle. Fig. 9 is a cross-sectional view of the capacitor 1. Fig. 10 is an exploded perspective view of a capacitor element 10 included in the capacitor 1.

[0024] 7, capacitor 1 includes a capacitor element (wound element) 10, a case (outer packaging) 20, a sealing member 30, an electrolyte 40, and a base plate 50. Capacitor element 10 includes an anode 101 (anode foil 11 and anode lead terminal 14), a cathode 102 (cathode foil 12 and cathode lead terminal 15), and a separator 13.

[0025] The anode foil 11 comprises a metal foil whose surface has been roughened by, for example, etching or the like. The metal foil is, for example, an aluminum foil. The material of the metal foil is preferably a valve metal such as aluminum, tantalum, niobium, or an alloy thereof. A dielectric film (dielectric layer) 16 is formed on the surface of the metal foil (see FIG. 9). The dielectric film 16 is formed, for example, by subjecting the metal foil to a chemical conversion treatment. The chemical conversion treatment is performed, for example, by immersing the metal foil in a chemical conversion solution and applying heat and voltage as necessary.

[0026] The cathode foil 12 includes, for example, a metal foil. The metal foil is, for example, an aluminum foil. The material of the metal foil is preferably a valve metal such as aluminum, tantalum, or niobium, or an alloy thereof. The metal foil of the cathode foil 12 may be subjected to a surface roughening treatment and / or a chemical conversion treatment, as necessary. The surface of the metal foil of the cathode foil 12 may be covered with a carbon coating, a titanium coating, or the like.

[0027] Separator 13 is disposed between anode foil 11 and cathode foil 12 to prevent contact between anode foil 11 and cathode foil 12. Capacitor element 10 includes a pair of separators 13. Separator 13 is formed of an electrically insulating material. Separator 13 is not particularly limited, and may be, for example, insulating paper or a nonwoven fabric mainly composed of cellulose, polyethylene terephthalate, vinylon, polyamide, glass, or the like.

[0028] The anode lead terminal 14 is connected to the anode foil 11. There are no particular limitations on the material of the anode lead terminal 14 as long as it is a conductive material. The anode lead terminal 14 integrally includes a lead tab 141 and a terminal plate 142. The lead tab 141 is connected to the anode foil 11 inside the case 20. The terminal plate 142 is exposed to the outside of the case 20.

[0029] Cathode lead terminal 15 is connected to cathode foil 12. There are no particular limitations on the material of cathode lead terminal 15 as long as it is a conductive material. Cathode lead terminal 15 integrally includes a lead tab 151 and a terminal plate 152. Lead tab 151 is connected to cathode foil 12 inside case 20. Terminal plate 152 is exposed to the outside of case 20.

[0030] For example, an anode foil 11 connected to an anode lead terminal 14, one of a pair of separators 13, a cathode foil 12 connected to a cathode lead terminal 15, and the other of the pair of separators 13 are stacked in this order. The anode foil 11, the cathode foil 12, and the pair of separators 13 are then wound up into a roll to form a capacitor element (wound element) 10 in a cylindrical shape (see FIG. 10 ). The outermost periphery of the capacitor element 10 is fixed by a stop tape 17.

[0031] Case 20 is made of a material such as aluminum and has a cylindrical shape with an open bottom. Capacitor element 10 is housed in case 20 such that terminal plate 142 of anode lead terminal 14 and terminal plate 152 of cathode lead terminal 15 are exposed to the outside.

[0032] In the capacitor 1, an electrolyte 40 is disposed between the anode foil 11 and the cathode foil 12 in the case 20. The electrolyte 40 includes a conductive polymer. The conductive polymer material may be, for example, polypyrrole, polythiophene, polyaniline, or a derivative thereof, and may further include a dopant. The conductive polymer may be attached in the form of a film to at least a part of at least one of the surface of the dielectric film 16 formed on the surface of the metal foil of the anode foil 11, the surface of the cathode foil 12, and the surface of the separator 13. The electrolyte 40 includes an electrolytic solution. The electrolytic solution is injected into the case 20 after the capacitor element 10 is accommodated in the case 20.

[0033] The sealing member 30 is made of an elastic material such as rubber. The sealing member 30 is attached to the case 20 so as to close the opening in the lower surface of the case 20. The sealing member 30 has two through holes formed therein.

[0034] The seat plate 50 is made of an electrically insulating material. The seat plate 50 is attached to the lower part of the case 20. Two through holes are formed in the seat plate 50 at positions corresponding to the two through holes of the sealing member 30. In addition, two accommodation recesses are formed in the bottom surface (lower surface) of the seat plate 50, extending outward from the outlets of the through holes.

[0035] The anode lead terminal 14 and the cathode lead terminal 15 protruding from the inside of the case 20 to the outside are passed through the through hole of the sealing member 30 and the through hole of the seat plate 50, and are bent outward. The outwardly bent portion of the anode lead terminal 14 is accommodated in one of the two accommodating recesses of the seat plate 50 as a terminal plate 142. The outwardly bent portion of the cathode lead terminal 15 is accommodated in the other of the two accommodating recesses of the seat plate 50 as a terminal plate 152.

[0036] Capacitor 1 manufactured in this manner has an unavoidable equivalent series resistance ESR1 in addition to capacitance component C1, as shown in FIG.

[0037] Note that capacitor 1 may be configured such that anode lead terminal 14 and cathode lead terminal 15 do not include terminal plates 142, 152, but are rod-shaped lead terminals protruding from seat plate 50.

[0038] (2.2) Inspection system Next, the configuration of an inspection system 90 for the capacitor 1 will be described with reference to FIG.

[0039] The inspection system 90 is used to inspect the capacitor 1, for example, in an inspection process of the capacitor 1 that is carried out in the final stage of the manufacturing process of the capacitor 1. The inspection system 90 of this embodiment is a system for inspecting the inrush resistance characteristic of the capacitor 1, that is, the characteristic regarding the magnitude of the inrush current that can flow through the capacitor 1. Hereinafter, the inspection of the inrush resistance characteristic of the capacitor 1 using the inspection system 90 may be referred to as an "inrush inspection."

[0040] As shown in FIG. 1, the inspection system 90 includes, in addition to a first voltage application circuit 91, a second voltage application circuit 92, and a control circuit 93, a connection section 94, a discharge circuit 95, a voltage measurement circuit 96, a current detection circuit 97, and an inspection circuit 98.

[0041] A capacitor (test target capacitor) 1 is detachably connected to the connection part 94. The connection part 94 includes a first terminal 941 and a second terminal 942 to which the anode 101 and the cathode 102 of the capacitor 1 are respectively connected. The test system 90 tests the capacitor 1 connected to the connection part 94.

[0042] The first voltage application circuit 91 applies a first voltage V1 to the capacitor 1. The first voltage application circuit 91 includes a first power supply 911, a first switch 912, and a charging resistor 913.

[0043] The first power supply 911 is a voltage supply source for applying a first voltage V1 to the capacitor 1. As described above, the magnitude of the first voltage V1 here is a value that coincides with the rated voltage of the capacitor (test target capacitor) 1. The first switch 912 switches on and off the application of the first voltage V1 to the connection part 94 (capacitor 1).

[0044] More specifically, the first power source 911, the first switch 912, and the charging resistor 913 are connected in series. A series circuit of the first power source 911, the first switch 912, and the charging resistor 913 is connected across the connection part 94. The positive electrode of the first power source 911 is connected to the first terminal 941 via the series circuit of the first switch 912 and the charging resistor 913. The negative electrode of the first power source 911 is connected to the second terminal 942 (via the current detection circuit 97 in the example of FIG. 1). When the first switch 912 is turned on, the first power source 911 applies a first voltage V1 to the capacitor 1 connected to the connection part 94 via the charging resistor 913.

[0045] The second voltage application circuit 92 applies a second voltage V2 to the capacitor 1. The second voltage application circuit 92 includes a second power supply 921, a second switch 922, and an inrush supply capacitor 923.

[0046] The second power supply 921 is a voltage supply source for applying a second voltage V2 to the capacitor 1. The second voltage V2 is a voltage higher than the first voltage V1. The second voltage V2 is, for example, 1.1 times or more the first voltage V1.

[0047] The inrush supply capacitor 923 is connected between both ends of the second power supply 921. The inrush supply capacitor 923 is charged to the second voltage V2 by the second power supply 921. The inrush supply capacitor 923 is provided to ensure the amount of current that can be supplied from the second voltage application circuit 92. In other words, the amount of current that can be instantaneously supplied from the second power supply 921 has an upper limit according to the structure of the second power supply 921, etc. Therefore, in the second voltage application circuit 92, instead of directly discharging charge from the second power supply 921, the inrush supply capacitor 923 is made to temporarily hold charge and then the charge is discharged from the inrush supply capacitor 923. This makes it possible to increase the amount of current that can be supplied from the second voltage application circuit 92.

[0048] The second switch 922 switches on and off the connection between the second power source 921 and the inrush supply capacitor 923 and the connection part 94. More specifically, the second switch 922 is connected in series with the parallel circuit of the second power source 921 and the inrush supply capacitor 923. The series circuit of the parallel circuit of the second power source 921 and the inrush supply capacitor 923 and the second switch 922 is connected across the connection part 94. The connection point of the positive electrode of the second power source 921 and the anode of the inrush supply capacitor 923 is connected to the first terminal 941 via the second switch 922. The connection point of the negative electrode of the second power source 921 and the cathode of the inrush supply capacitor 923 is connected to the second terminal 942 (via the current detection circuit 97 in the example of FIG. 1). When the second switch 922 is turned on, the parallel circuit of the second power source 921 and the inrush supply capacitor 923 applies a second voltage V2 to the capacitor 1 connected to the connection part 94. In short, the second switch 922 switches the application of the second voltage V2 to the capacitor 1 on and off.

[0049] The second voltage application circuit 92 is connected in parallel with the first voltage application circuit 91. More specifically, a series circuit of the second switch 922 and the parallel circuit of the second power supply 921 and the inrush supply capacitor 923 is connected between both ends of the series circuit of the first power supply 911, the first switch 912, and the charging resistor 913.

[0050] The discharge circuit 95 discharges the capacitor 1. The discharge circuit 95 includes a discharge resistor 951 and a third switch (discharge switch) 952. The third switch 952 switches the connection of the capacitor 1 to the discharge resistor 951 on and off.

[0051] More specifically, the discharge resistor 951 and the third switch 952 are connected in series. The series circuit of the discharge resistor 951 and the third switch 952 is connected across the connection part 94. The third switch 952 is connected to the first terminal 941. The discharge resistor 951 is connected to the second terminal 942. When the third switch 952 is turned on, the discharge resistor 951 releases charge from the capacitor 1 connected to the connection part 94, thereby discharging the capacitor 1.

[0052] The voltage measurement circuit 96 is connected across the connection part 94. The voltage measurement circuit 96 includes a voltmeter 961. The voltage measurement circuit 96 measures the voltage across the connection part 94, in other words, the voltage across the capacitor 1 connected to the connection part 94.

[0053] The control circuit 93 controls the on / off of the first switch 912, the second switch 922, and the third switch 952. In this embodiment, the control circuit 93 controls the on and off timing of the first switch 912, the second switch 922, and the third switch 952 based on the measurement result of the voltage measurement circuit 96. That is, the control circuit 93 controls the first voltage application circuit 91, the second voltage application circuit 92, and the discharge circuit 95 based on the voltage V10 across the capacitor 1 measured by the voltage measurement circuit 96.

[0054] The control circuit 93 controls the discharge circuit 95 so as to discharge the capacitor 1 before supplying an inrush current to the capacitor 1. Specifically, the control circuit 93 turns off the first switch 912 and the second switch 922 and turns on the third switch 952, thereby discharging the capacitor 1 connected to the connection part 94.

[0055] The control circuit 93 turns on the first switch 912 and the second switch 922 and turns off the third switch 952, thereby applying the first voltage V1 and the second voltage V2 to the capacitor 1 connected to the connection part 94. By applying the first voltage V1 and the second voltage V2 to the discharged capacitor 1, an inrush current according to the magnitude of the second voltage V2, which is the larger of the first voltage V1 and the second voltage V2, is supplied to the capacitor 1. The capacitor 1 is charged by the inrush current.

[0056] The control circuit 93 turns on the first switch 912 and turns off the second switch 922 and the third switch 952, thereby applying the first voltage V1 to the capacitor 1 connected to the connection portion 94. Specifically, before the capacitor 1 is charged by the supply of the inrush current and the voltage V10 across the capacitor 1 reaches the first voltage V1, the control circuit 93 turns off the second switch 922 while keeping the first switch 912 on and the third switch 952 off. As a result, the control circuit 93 stops applying the second voltage V2 to the capacitor 1 and applies the first voltage V1 to the capacitor 1.

[0057] After stopping the application of the second voltage V2 to the capacitor 1, the control circuit 93 applies the first voltage V1 to the capacitor 1 for a predetermined inspection period T2 (see FIG. 2).

[0058] The current detection circuit 97 detects a current flowing through an electric wire in which the current detection circuit 97 is arranged. The current detection circuit 97 is inserted (connected) between the connection part 94 and the parallel circuit of the first voltage application circuit 91 and the second voltage application circuit 92. The current detection circuit 97 detects a current flowing between the capacitor 1 connected to the connection part 94 and the parallel circuit of the first voltage application circuit 91 and the second voltage application circuit 92. In other words, the current detection circuit 97 detects a current flowing through the capacitor 1.

[0059] The current detection circuit 97 includes, for example, a current detection resistor. The current detection resistor is connected in series with the parallel circuit of the first voltage application circuit 91 and the second voltage application circuit 92. The series circuit of the parallel circuit of the first voltage application circuit 91 and the second voltage application circuit 92 and the current detection resistor is connected between both ends of the connection portion 94. The current detection circuit 97 is not limited to a current detection resistor, and may be, for example, a current sensor such as a current transformer (CT).

[0060] The inspection circuit 98 inspects the capacitor 1. The inspection circuit 98 inspects the capacitor 1 based on the current detected by the current detection circuit 97. The inspection circuit 98 judges whether the capacitor 1 is good or bad based on the current detected by the current detection circuit 97.

[0061] The inspection circuit 98 inspects the capacitor 1 based on the current detected by the current detection circuit 97 when the inrush current is supplied. That is, the inspection circuit 98 inspects the capacitor 1 based on the inrush current supplied to the capacitor 1. The inspection circuit 98 also inspects the capacitor 1 based on the current detected by the current detection circuit 97 in an inspection period T2. The inspection period T2 is a predetermined period that is set after the supply of the inrush current ends. That is, the inspection circuit 98 inspects the capacitor 1 based on the behavior of the capacitor 1 after the inrush current is supplied to the capacitor 1.

[0062] 1, the inspection system 90 has a wiring resistance 99. The wiring resistance 99 is an unavoidable resistance component contained in wiring connecting each element of the inspection system 90. Here, in particular, the wiring resistance 99 between the connection part 94 (first terminal 941, second terminal 942) and the connection point 900 (first connection point 901, second connection point 902) of the first voltage application circuit 91 and the second voltage application circuit 92 is considered.

[0063] For example, connection portion 94 and connection point 900 are connected by a relatively long electric wire (e.g., a length on the order of meters), and the resistance component of this electric wire is considered as wiring resistance 99. In addition, the contact resistance between connection portion 94 and capacitor 1 is also considered as wiring resistance 99. Note that, in reality, resistance components of conductor patterns exist inside first voltage application circuit 91, second voltage application circuit, etc., but these are ignored since they are sufficiently smaller than the wiring resistance 99 of the electric wire, etc.

[0064] (2.3) Operation An example of the operation of the inspection system 90 during inrush inspection will be described with reference to Figs. 2, 3, and 12. The first to third rows of Fig. 2 respectively show the states of the first switch (SW1) 912, the second switch (SW2) 922, and the third switch (SW3) 952. The upper row of Fig. 3 shows the voltage V10 across the capacitor 1. The voltage V10 across the capacitor 1 is a value measured by, for example, a voltage measurement circuit 96. The lower row of Fig. 3 shows the current I10 flowing through the capacitor 1. The current I10 flowing through the capacitor 1 is a value detected by, for example, a current detection circuit 97. Fig. 12 shows a flowchart of this operation example.

[0065] When the capacitor (test target capacitor) 1 is connected to the connection part 94, the control circuit 93 first turns off the first switch 912 and the second switch 922 and turns on the third switch 952 (period T0 in FIG. 2) as a preliminary step of the inrush test. This causes the capacitor 1 to be discharged typically to 0 V via the discharge resistor 951 (see the upper part of FIG. 3; ST1 in FIG. 12).

[0066] When the inspection starts, the control circuit 93 turns on the first switch 912 and the second switch 922, and turns off the third switch 952 (time t1 in FIG. 2). As a result, the capacitor 1 is connected to the parallel circuit of the first voltage application circuit 91 and the second voltage application circuit 92, and the first voltage V1 and the second voltage V2 are applied to the capacitor 1 (ST2 in FIG. 12). By applying the first voltage V1 and the second voltage V2 to the discharged capacitor 1, an inrush current is supplied to the capacitor 1 (see the lower part of FIG. 3; ST3 in FIG. 12).

[0067] The magnitude of the inrush current depends on the magnitude of the second voltage V2 and the magnitude of the resistance component of the electric path to which the second voltage V2 is applied. The peak value Ip of the inrush current is typically expressed as Ip=V2 / (R99+ESR1), where V2 is the magnitude of the second voltage V2, R99 is the magnitude of the wiring resistance 99, and ESR1 is the magnitude of the equivalent series resistance ESR1 of the capacitor 1. Here, the peak value Ip of the inrush current refers to the maximum value (reference value) of the inrush current supplied from the inspection system 90 to the capacitor 1 when the capacitor 1 is normal (a non-defective product).

[0068] The inrush current rapidly charges the capacitor 1. As the capacitor 1 is charged, the voltage V10 across the capacitor 1 rapidly increases over time from the value (0 V) at the time of discharge (time t1) (see the upper part of Figure 3).

[0069] Moreover, after the current supplied to the capacitor 1 (the inrush current) reaches the peak value Ip, it rapidly decreases in accordance with the increase in the voltage V10 across the capacitor 1 (see the lower part of FIG. 3).

[0070] When the voltage V10 across the capacitor 1 increases and reaches the first voltage V1, the control circuit 93 turns off the second switch 922 while keeping the first switch 912 on (time point t2).

[0071] Specifically, the control circuit 93 acquires a measurement result of the voltage V10 across the capacitor 1 from the voltage measurement circuit 96. The control circuit 93 compares the voltage V10 across the capacitor 1 with a threshold voltage. The threshold voltage is set to a value equal to the magnitude of the first voltage V1. When the voltage V10 across the capacitor 1 reaches the threshold voltage, the control circuit 93 turns off the second switch 922.

[0072] As a result, the application of the second voltage V2 to the capacitor 1 is stopped (ST4 in FIG. 12), and only the first voltage V1 is applied to the capacitor 1. At this point, the voltage V10 across the capacitor 1 has reached the first voltage V1, so that charging of the capacitor 1 is completed, and the supply of charge to the capacitor 1 is stopped.

[0073] After turning off the second switch 922, the control circuit 93 keeps the first switch 912 on and keeps the second switch 922 and the third switch 952 off for a predetermined inspection period T2 (see FIG. 2). That is, after stopping the application of the second voltage V2 to the capacitor 1, the control circuit 93 applies the first voltage V1 to the capacitor 1 for the inspection period T2.

[0074] After the end of the inspection period T2, the control circuit 93 turns off the first switch 912 and turns on the third switch 952 while keeping the second switch 922 off (time t3). As a result, the charge stored in the capacitor 1 is discharged via the discharge circuit 95, and the voltage V10 across the capacitor 1 decreases to 0 V over time (see the upper part of FIG. 3).

[0075] The inspection circuit 98 inspects the capacitor 1 based on the current I10 flowing through the capacitor 1 during the period (inrush current supply period) T1 (the period from time t1 to time t2) between time t1 and time t2, and the current I10 flowing through the capacitor 1 during the inspection period T2 (the period from time t2 to t3) (ST5 in FIG. 12).

[0076] (2.4) Inspection The inspection process of the capacitor 1 by the inspection circuit 98 will be described with reference to FIGS.

[0077] FIG. 3 shows an example of the voltage V10 across the capacitor 1 and the current I10 flowing through the capacitor 1 when the capacitor 1 is a non-defective product.

[0078] FIG. 4 shows an example of the voltage V10 across the capacitor 1 and the current I10 flowing through the capacitor 1 when the capacitor 1 is defective.

[0079] As described above, when the constants of the circuit elements in the inspection system 90 (the second voltage V2 and the wiring resistance 99) are constant, the peak value Ip of the inrush current is determined by the equivalent series resistance ESR1 of the capacitor 1. Therefore, for example, by determining whether the peak value of the current I10 detected during the inrush current supply period T1 falls within a predetermined range, it becomes possible to determine whether the capacitor 1 is good or bad.

[0080] For example, if a spark occurs in capacitor 1 during inrush current supply period T1, the stored charge is released from capacitor 1, causing a discharge current 32 larger than peak value Ip (reference value) to flow, as shown in Fig. 4. Therefore, when inspection circuit 98 detects discharge current 32 during inrush current supply period T1, it can determine that capacitor 1 under inspection is defective.

[0081] Furthermore, if a spark occurs in the capacitor 1 during the inspection period T2, a relatively large current change 34 is detected during the inspection period T2, as shown in Fig. 4. Therefore, when the inspection circuit 98 detects a current change 34 exceeding a threshold during the inspection period T2, it can determine that the capacitor 1 being inspected is defective.

[0082] When a discharge current 32 flows during the inrush current supply period T1, a voltage drop 31 occurs in the voltage V10 across the capacitor 1. Furthermore, when a current change 34 occurs during the inspection period T2, a voltage change 33 occurs in the voltage V10 across the capacitor 1. For this reason, the inspection circuit 98 can also determine whether the capacitor 1 is good or bad by using the voltage measured by the voltage measurement circuit 96 instead of or in addition to the detection result of the current detection circuit 97.

[0083] (2.5) Advantages As described above, the inspection system 90 of this embodiment makes it possible to supply an inrush current of a peak value Ip=V2 / (R99+ESR1) to the capacitor 1. The peak value Ip depends on the second voltage V2. Therefore, by appropriately selecting the second power supply 921 (voltage supply source of the second voltage V2), it becomes possible to supply an inrush current of a desired magnitude to the capacitor 1.

[0084] Furthermore, the control circuit 93 stops the application of the second voltage V2 to the capacitor 1 before the voltage V10 across the capacitor 1 reaches the first voltage V1 (for example, the rated voltage). Therefore, it is possible to prevent a voltage exceeding the first voltage V1 (the rated voltage) from being applied to the capacitor 1 while supplying an inrush current of a desired magnitude.

[0085] The inspection system 90 of the present embodiment is particularly useful when the magnitude of the equivalent series resistance ESR1 of the capacitor 1 is comparable to or smaller than the magnitude of the wiring resistance 99. This point will be described below with reference to a comparison with the inspection system 80 of the comparative example.

[0086] 14, the inspection system 80 of the comparative example includes a voltage application circuit 81, a control circuit 83, a connection unit 84, a current detection circuit 87, and an inspection circuit 88. The connection unit 84 (first terminal 841 and second terminal 842), the current detection circuit 87, the inspection circuit 88, and the wiring resistance 89 are similar to the connection unit 94 (first terminal 941 and second terminal 942), the current detection circuit 97, the inspection circuit 98, and the wiring resistance 99 of the inspection system 90 of the above embodiment, and therefore the description thereof will be omitted. Although omitted in FIG. 14, the inspection system 80 of the comparative example may also include a discharge circuit and a voltage measurement circuit similar to the discharge circuit 95 and the voltage measurement circuit 96 of the inspection system 90 of the embodiment.

[0087] An inspection system 80 of the comparative example includes a voltage application circuit 81 instead of the first voltage application circuit 91 and the second voltage application circuit 92. The voltage application circuit 81 includes a power supply 811, a switch 812, and an inrush supply capacitor 813. The power supply 811 and the inrush supply capacitor 813 are connected in parallel, and this parallel circuit is connected in series to the switch 812. A series circuit of the switch 812 and the parallel circuit of the power supply 811 and the inrush supply capacitor 813 is connected to a connection unit 84. A control circuit 83 controls the on / off of the switch 812.

[0088] In the comparative test system 80, power supply 811 is a voltage supply source for applying voltage V0 through inrush supply capacitor 813 to connection 84 (capacitor 1).

[0089] In inspection system 80 of the comparative example, after the discharged capacitor 1 is connected to connection part 84, control circuit 83 turns on switch 812, and an inrush current is supplied from voltage application circuit 81 to capacitor 1. The peak value Ip0 of the inrush current is expressed as Ip0=V0 / (R89+ESR1), where V0 is the magnitude of voltage V0, R89 is the magnitude of wiring resistance 89, and ESR1 is the magnitude of equivalent series resistance ESR1 of capacitor 1. In addition, in inspection system 80, after the inrush current is supplied, switch 812 is kept on for a predetermined inspection period to apply voltage V0 to capacitor 1. Then, capacitor 1 is inspected based on the behavior of the current detected during the inspection period.

[0090] Here, when performing an inrush inspection of capacitor 1, it is preferable to perform the inspection by passing through capacitor 1 the maximum inrush current that may flow through capacitor 1 in the circuit in which capacitor 1 is actually used (hereinafter referred to as the "applied circuit").

[0091] For example, when the magnitude ESR1 of the equivalent series resistance ESR1 of the capacitor 1 is sufficiently (for example, by about one order of magnitude) larger than the magnitude R89 of the wiring resistance 89, the peak value Ip0 of the inrush current that can be supplied by the inspection system 80 can be approximated as Ip0≈V0 / ESR1. In addition, the peak value IpA of the maximum inrush current that can flow through the capacitor 1 in the application circuit can be expressed as IpA=VA / (RA+ESR1), where VA is the voltage applied to the capacitor 1 in the application circuit and RA is the wiring resistance of the application circuit. In addition, when RA is sufficiently smaller than the magnitude ESR1 of the equivalent series resistance ESR1 in the application circuit, the peak value IpA can be approximated as IpA≈VA / ESR1. Therefore, if the rated voltage of the capacitor 1 is adopted as the voltage that can be applied to the capacitor 1 as the voltage V0 of the power supply 811, the maximum inrush current that can flow in the application circuit can be passed through the capacitor 1 by the inspection system 80.

[0092] On the other hand, when the magnitude ESR1 of the equivalent series resistance ESR1 of the capacitor 1 is equal to or smaller than the magnitude R89 of the wiring resistance 89, the peak value Ip of the in-rush current that can be supplied by the inspection system 80 depends greatly on the wiring resistance R89. For example, when the magnitude ESR1 of the equivalent series resistance ESR1 is sufficiently smaller than the magnitude R89 of the wiring resistance 89, the peak value Ip0 of the in-rush current that can be supplied by the inspection system 80 is approximated as Ip≈V0 / R89. In addition, the peak value IpA of the application circuit is also expressed as IpA=VA / (RA+ESR1)≈VA / RA. Therefore, for example, when the magnitude RA of the wiring resistance of the application circuit is smaller than the magnitude R89 of the wiring resistance 89 of the inspection system 80 (RA<R89)には、V0=VAとするとIpA> When the inrush current becomes Ip0, the inspection system 80 may not be able to supply the maximum inrush current that may flow in the application circuit to the capacitor 1.

[0093] In the inspection system 80 of the comparative example, in order to increase the peak value Ip0 of the inrush current, it is possible to increase the magnitude V0 of the voltage V0. However, in the inspection system 80 of the comparative example, the voltage V0 is applied to the capacitor 1 from the voltage application circuit 81 during the inspection period. Therefore, if the magnitude of the voltage V0 is made larger than the rated voltage, a voltage higher than the rated voltage is applied to the capacitor 1 during the inspection period, and an excessive load is applied to the capacitor 1. In short, in the inspection system 80 of the comparative example, when the magnitude of the equivalent series resistance ESR1 of the capacitor 1 is similar to or smaller than the magnitude of the wiring resistance 99, there is a possibility that the desired inrush current cannot be supplied to the capacitor 1.

[0094] On the other hand, in the inspection system 90 of this embodiment, the peak value Ip of the in-rush current can be freely set by appropriately adjusting the magnitude V2 of the second voltage V2. Moreover, since the application of the second voltage V2 is stopped before the voltage V10 across the capacitor 1 reaches the first voltage V1, the voltage V10 across the capacitor 1 does not exceed the first voltage V1. Therefore, excessive load on the capacitor 1 is also suppressed.

[0095] (2.6) Specific Examples FIG. 5 shows a specific example of the circuit configuration of the inspection system 90. In FIG.

[0096] As shown in Fig. 5, in this specific example, the first switch 912, the second switch 922, and the third switch 952 are respectively composed of a first transistor Tr1, a second transistor Tr2, and a third transistor Tr3. The first transistor Tr1, the second transistor Tr2, and the third transistor Tr3 are each an NPN type transistor. In this specific example, the charging resistor 913 is composed of a series circuit of a resistor R1 and a resistor R2. In this specific example, the voltage measurement circuit 96 is omitted. In this specific example, the same components as those in the circuit of Fig. 1 are denoted by the same reference numerals and will not be described as appropriate.

[0097] 5, the first transistor Tr1 has a collector connected to the positive electrode of the first power supply 911 via a resistor R1, an emitter connected to a connection point between a first end of the resistor R2 and a base of the second transistor Tr2, and a base connected to the control circuit 93. The second transistor Tr2 has a collector connected to a connection point between a positive electrode of the second power supply 921 and an anode of an inrush supply capacitor 923, an emitter connected to the second end of the resistor R2, and a base connected to a connection point between the emitter of the first transistor and a first end of the resistor R2. When the first transistor Tr1 is turned on, a voltage supply source (first power supply 911) of the first voltage V1 is connected to the base of the second transistor Tr2, and the voltage across the resistor R2 is applied between the base and emitter of the second transistor Tr2. The third transistor Tr3 has a collector connected to the connection point between the emitter of the second transistor Tr2 and the second end of the resistor R2, an emitter connected to the connection point of the negative electrode of the first power source 911, the negative electrode of the second power source 921, and the cathode of the inrush supply capacitor 923 via a discharge resistor 951, and a base connected to the control circuit 93.

[0098] The operation of the capacitor 1 according to this example during an inrush inspection will be described with reference to Fig. 6. The first to third rows of Fig. 6 show the states of the first transistor Tr1, the second transistor Tr2, and the third transistor Tr3, respectively.

[0099] As a preliminary step of an inrush inspection, the control circuit 93 turns off the first transistor Tr1 and turns on the third transistor Tr3 to discharge the capacitor 1. The second transistor Tr2 is maintained off because the first transistor Tr1 is off.

[0100] When the inspection starts, the control circuit 93 turns off the third transistor Tr3. The control circuit 93 also outputs an ON signal to the base of the first transistor Tr1 to turn on the first transistor Tr1 (time t11). When the first transistor Tr1 turns on, a current flows through the second resistor R2, and the base-emitter voltage of the second transistor Tr2 exceeds the threshold value (0.7 V), so that the second transistor Tr2 turns on slightly later than the first transistor Tr1. In this way, when the control circuit 93 turns on the first transistor Tr1, the second transistor Tr2 is turned on by a voltage corresponding to the difference between the output voltage (first voltage V1) from the first power supply 911 and the voltage V10 across the capacitor 1. Note that time t11 corresponds to time t1 in FIG. 2.

[0101] When the first transistor Tr1 and the second transistor Tr2 are turned on, the first voltage V1 and the second voltage V2 are applied to the capacitor 1, and an inrush current is supplied to the capacitor 1, which rapidly charges the capacitor 1. As the capacitor 1 is charged, the voltage V10 across the capacitor 1 rapidly increases over time from the value (0 V) at the time of discharge (period T1 in FIG. 2).

[0102] When the voltage V10 across the capacitor 1 rises to near the output voltage (first voltage V1) of the first power supply 911, the current flowing through the second resistor R2 decreases, causing the voltage across the second resistor R2 to fall below the threshold of the second transistor Tr2, and the second transistor Tr2 turns off (time t12). This stops the application of the second voltage V2 to the capacitor 1, and only the first voltage V1 is applied to the capacitor 1. Time t12 corresponds to time t2 in FIG. 2.

[0103] After the second transistor Tr2 is turned off, the control circuit 93 applies the first voltage V1 to the capacitor 1 by keeping the first transistor Tr1 on and the third transistor Tr3 off for a predetermined inspection period T2 (see Figure 2).

[0104] After the inspection period T2 ends, the control circuit 93 turns off the first transistor Tr1 and turns on the third transistor Tr3 (at time t13). As a result, the charge stored in the capacitor 1 is discharged via the discharge circuit 95, and the voltage V10 across the capacitor 1 decreases to 0 V over time.

[0105] In this way, according to this example, it is possible to automatically turn on and off the second transistor Tr2, and it is also possible to omit the voltage measurement circuit 96.

[0106] (3) Variations The above-described embodiment is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. In addition, the same function as the inspection system 90 may be embodied in an inspection method, a (computer) program, or a non-transitory recording medium on which a program is recorded, etc.

[0107] 12, a first voltage V1 and a second voltage V2 larger than the first voltage V1 are applied to a capacitor 1 (a capacitor to be inspected) to supply an inrush current to the capacitor 1 to charge the capacitor 1 (ST2, ST3). The inspection method also includes stopping the application of the second voltage V2 to the capacitor 1 before a voltage V10 across the capacitor 1 reaches the first voltage V1 due to the supply of the inrush current (ST4).

[0108] 13, a manufacturing method according to one embodiment includes a step (ST11) of manufacturing capacitor 1 and a step (ST12) of inspecting capacitor 1. The step of inspecting capacitor 1 is performed based on the inspection method described above.

[0109] Modifications of the embodiment are listed below. The modifications described below can be applied in appropriate combination.

[0110] The inspection system 90 in the present disclosure includes a computer system in the control circuit 93, etc. The computer system is mainly composed of a processor and a memory as hardware. The function of the control circuit 93 in the present disclosure is realized by the processor executing a program recorded in the memory of the computer system. The program may be pre-recorded in the memory of the computer system, may be provided through an electric communication line, or may be provided by being recorded in a non-transitory recording medium such as a memory card, an optical disk, or a hard disk drive that can be read by the computer system. The processor of the computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large scale integrated circuit (LSI). The integrated circuits such as IC or LSI here are called by different names depending on the degree of integration, and include integrated circuits called system LSI, VLSI (Very Large Scale Integration), or ULSI (Ultra Large Scale Integration). Furthermore, a field-programmable gate array (FPGA) that is programmed after the manufacture of the LSI, or a logic device that can reconfigure the connection relationship inside the LSI or the circuit partition inside the LSI, can also be adopted as a processor. The electronic circuits may be integrated in one chip or distributed among multiple chips. The chips may be integrated in one device or distributed among multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Thus, the microcontroller is also composed of one or more electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.

[0111] Furthermore, it is not essential for the inspection system 90 that the multiple functions of the control circuit 93 are concentrated in one housing, and the components of the control circuit 93 may be distributed across multiple housings. Furthermore, at least some of the functions of the control circuit 93 may be realized by, for example, a server or a cloud (cloud computing), etc.

[0112] (3.1) Variation 1 An inspection system 90 according to the first modification will be described with reference to FIGS.

[0113] 15, in the inspection system 90 of this modification, a series circuit of a parallel circuit of a second power source 921 and an inrush supply capacitor 923 and a second switch 922 is connected between both ends of a series circuit of a first power source 911 and a charging resistor 913. In addition, the first switch 912 is connected between a connection point of the second switch 922 and the charging resistor 913 and a connection part 94 (first terminal 941). Since other configurations are the same as those in FIG. 1, detailed description will be omitted.

[0114] 16 shows a specific example of the circuit configuration of the inspection system 90 of this modified example. This specific example includes a diode D1, the cathode of which is connected to the connection point between the collector of the first transistor Tr1 and the emitter of the second transistor Tr2, and the anode of which is connected to the first end of the third resistor R3. The collector of the first transistor Tr1 is connected to the connection point between the cathode of the diode D1 and the emitter of the second transistor Tr2, the emitter is connected to the first terminal 941, and the base is connected to the control circuit 93 (see FIG. 5). The collector of the second transistor Tr2 is connected to the connection point between the positive electrode of the second power supply 921 and the anode of the inrush supply capacitor 923, the emitter is connected to the connection point between the collector of the first transistor Tr1 and the cathode of the diode D1, and the base is connected to the connection point between the second end of the third resistor R3 and the positive electrode of the first power supply 911 via the fourth resistor R4. That is, a voltage supply source of the first voltage V1 is connected (directly) to the base of the second transistor Tr2 via a fourth resistor R4. The third transistor Tr3 has a collector connected to the emitter of the first transistor Tr1, an emitter connected to a connection point of the negative electrode of the first power supply 911, the negative electrode of the second power supply 921, and the cathode of the inrush supply capacitor 923 via a discharge resistor 951, and a base connected to the control circuit 93. Note that the control circuit 93, the current detection circuit 97, and the inspection circuit 98 are not shown in Figs. 15 and 16.

[0115] The operation of the capacitor 1 according to the specific example of this modification during inrush inspection will be described with reference to Fig. 17. The first to third rows of Fig. 17 show the states of the first transistor Tr1, the second transistor Tr2, and the third transistor Tr3, respectively. The fourth row of Fig. 17 shows the collector potential E 2C , the base potential E 2B , the emitter potential E 2E The relationship between the collector potential E 2C is maintained at the positive potential of the second power supply 921. The example of Fig. 17 shows a case where the magnitude R99 of the wiring resistance 99 is sufficiently larger than the sum of the on-resistance of the first transistor Tr1 and the on-resistance of the second transistor Tr2.

[0116] As a preliminary step of an inrush test, the control circuit 93 (see FIG. 5) turns off the first transistor Tr1 and turns on the third transistor Tr3 to discharge the capacitor 1. In this state, since the first transistor Tr1 is off, no current flows through the diode D1 and the third resistor R3, and since the base-emitter voltage of the second transistor Tr2 is lower than the threshold value (0.7 V), the second transistor Tr2 is maintained off.

[0117] When the test starts, the control circuit 93 turns off the third transistor Tr3. The control circuit 93 also outputs an ON signal to the base of the first transistor Tr1 to turn on the first transistor Tr1 (time t21). When the first transistor Tr1 turns on, a current flows through the diode D1 and the third resistor R3, and the potential E of the emitter of the second transistor Tr2 increases. 2E The base-emitter voltage of the second transistor Tr2 becomes equal to or higher than the threshold voltage (0.7 V), and the second transistor Tr2 is turned on slightly later than the first transistor Tr1. Note that immediately after the first transistor Tr1 is turned on, the emitter potential E 2EThe potential drops to the negative potential (reference potential) of the first power supply 911, but is not shown in FIG.

[0118] When the second transistor Tr2 is turned on, the first voltage V1 and the second voltage V2 are applied to the capacitor 1, and an inrush current is supplied to the capacitor 1, and the capacitor 1 is rapidly charged by the inrush current. As the capacitor 1 is charged, the voltage V10 across the capacitor 1 increases rapidly over time from the value (0V) at the time of discharge. As the capacitor 1 is charged, the current flowing through the wiring resistor 99 decreases, and the voltage across the wiring resistor 99 decreases over time. A voltage determined depending on the difference between the output voltage of the first power supply 911, the voltage V10 across the capacitor 1, and the voltage drop due to the current flowing through the wiring resistor 99 is applied between the base and emitter of the second transistor Tr2, and the second transistor Tr2 is maintained on. In this way, when the control circuit 93 turns on the first transistor Tr1, the second transistor Tr2 is turned on by a voltage depending on the difference between the output voltage (first voltage V1) from the first power supply 911 and the voltage V10 across the capacitor 1.

[0119] When the base-emitter voltage of the second transistor Tr2 decreases and falls below the threshold (0.7 V) due to an increase in the voltage V10 across the capacitor 1, the second transistor Tr2 turns off (time t22), thereby stopping the application of the second voltage V2 to the capacitor 1, and only the first voltage V1 is applied to the capacitor 1 via the third resistor R3 and the diode D1.

[0120] After the second transistor Tr2 is turned off, the control circuit 93 applies the first voltage V1 to the capacitor 1 by keeping the first transistor Tr1 on and the third transistor Tr3 off for a predetermined inspection period T2 (see Figure 2).

[0121] After the inspection period T2 ends, the control circuit 93 turns off the first transistor Tr1 and turns on the third transistor Tr3 (time t23), causing the charge stored in the capacitor 1 to be discharged via the discharge circuit 95, and the voltage V10 across the capacitor 1 decreases to 0 V over time.

[0122] In this manner, this modification also makes it possible to supply a desired inrush current to the capacitor 1. In addition, it becomes possible to prevent a voltage higher than the first voltage V1 from being applied to the capacitor 1.

[0123] (3.2) Other Modifications In one modified example, at least one of the first transistor Tr1 to the third transistor Tr3 may be a FET (Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor).

[0124] In one modified example, the first voltage V1 may be set to a value different from the rated voltage of the capacitor 1. The first voltage V1 is preferably set to a value close to the rated voltage of the capacitor 1, and is preferably set to a value smaller than the rated voltage of the capacitor 1.

[0125] In one modified example, the threshold voltage referred to by the control circuit 93 may be a value different from the first voltage V1.

[0126] In one variant, the detection of the current change between t2 and t3 may be performed by detecting the voltage across resistor 913.

[0127] In one modified example, at time point t1, the control circuit 93 does not have to turn on the first switch 912 and the second switch 922 and turn off the third switch 952 simultaneously. It is preferable that the control circuit 93 turn on the first switch 912 and the second switch 922 after the third switch 952 is turned off.

[0128] In one modified example, at time point t3, the control circuit 93 does not have to turn off the first switch 912 and turn on the third switch 952 simultaneously. It is preferable that the control circuit 93 turn off the first switch 912 before turning on the third switch 952.

[0129] In one variation, the magnitude of the second voltage V2 is preferably 1.5 times or more, and may be 2 times or more, that of the first voltage V1. In one variation, the magnitude of the second voltage V2 is preferably 10 times or less, and may be 5 times or less, 3 times or less, or 2 times or less, that of the first voltage V1.

[0130] (4) Description The following aspects are disclosed from the above-described embodiment and modified examples.

[0131] The inspection system (90) of the first embodiment includes a first voltage application circuit (91), a second voltage application circuit (92), and a control circuit (93). The first voltage application circuit (91) applies a first voltage (V1) to a capacitor under inspection (capacitor 1). The second voltage application circuit (92) applies a second voltage (V2) higher than the first voltage (V1) to the capacitor under inspection. The control circuit (93) controls the first voltage application circuit (91) and the second voltage application circuit (92) to apply the first voltage (V1) and the second voltage (V2) to the capacitor under inspection, thereby supplying an inrush current to the capacitor under inspection and charging the capacitor under inspection. The control circuit (93) controls the first voltage application circuit (91) and the second voltage application circuit (92) to stop application of the second voltage (V2) to the capacitor under inspection before the voltage across the capacitor under inspection reaches the first voltage (V1) due to the supply of the inrush current.

[0132] According to this aspect, it is possible to supply a desired magnitude of inrush current to the capacitor under test. Also, while being able to supply a desired magnitude of inrush current, it is possible to prevent the capacitor under test from being charged to the first voltage (V1) or higher.

[0133] In the inspection system (90) of the second aspect, in the first aspect, the second voltage application circuit (92) includes a power supply (second power supply 921) and an inrush supply capacitor (923). The inrush supply capacitor (923) is charged to a second voltage (V2) by the power supply and supplies the inrush current to the capacitor under inspection.

[0134] According to this embodiment, it is possible to increase the amount of current that can be supplied from the second voltage application circuit (92).

[0135] The inspection system (90) of the third aspect is the inspection system of the first or second aspect, further comprising a discharge circuit (95) for discharging the capacitor under test. The control circuit (93) controls the discharge circuit (95) to discharge the capacitor under test before supplying an inrush current to the capacitor under test.

[0136] According to this aspect, it is possible to discharge the capacitor to be tested before the test.

[0137] In the inspection system (90) of the fourth aspect, in the third aspect, the discharge circuit (95) includes a discharge resistor (951) and a discharge switch (952). The discharge switch (952) switches on and off the connection of the capacitor under test to the discharge resistor (951). The control circuit (93) turns on the discharge switch (952) to discharge the capacitor under test.

[0138] According to this embodiment, the discharge circuit (95) can be realized with a simple configuration.

[0139] In the inspection system (90) of the fifth aspect, in any one of the first to fourth aspects, the first voltage application circuit (91) includes a first switch (912) that switches on and off the application of a first voltage (V1) to the capacitor under test. The second voltage application circuit (92) includes a second switch (922) that switches on and off the application of a second voltage (V2) to the capacitor under test. The control circuit (93) applies the first voltage (V1) and the second voltage (V2) to the capacitor under test by turning on the first switch (912) and the second switch (922). The control circuit (93) turns off the second switch (922) before the voltage (V10) across the capacitor under test reaches the first voltage (V1).

[0140] According to this embodiment, the first voltage application circuit (91) and the second voltage application circuit (92) can be realized with a simple configuration.

[0141] In the inspection system (90) of the sixth aspect, in the fifth aspect, the second switch (922) includes a transistor (second transistor Tr2). When the control circuit (93) turns on the first switch (912), a voltage supply source (first power supply 911) of a first voltage (V1) is connected to the base or gate of the transistor, and when the control circuit (93) turns on the first switch (912), the transistor is turned on by a voltage corresponding to the difference between the output voltage from the voltage supply limit and the voltage (V10) across the capacitor to be inspected.

[0142] According to this embodiment, the second switch (922) can be automatically turned on and off by the circuit configuration.

[0143] The inspection system (90) of the seventh aspect is any one of the first to fifth aspects, and further includes a voltage measurement circuit (96). The voltage measurement circuit (96) measures a voltage (V10) across the capacitor to be inspected. The control circuit (93) controls the first voltage application circuit (91) and the second voltage application circuit (92) based on the voltage (V10) across the capacitor measured by the voltage measurement circuit (96).

[0144] According to this configuration, it is possible to control the first voltage application circuit (91) and the second voltage application circuit (92) based on the measurement result of the voltage measurement circuit (96).

[0145] In the inspection system (90) of the eighth aspect, in any one of the first to seventh aspects, the second voltage (V2) is 1.1 times or more the first voltage (V1).

[0146] In the inspection system (90) of the ninth aspect, in any one of the first to eighth aspects, the inrush current is larger than the current that can be supplied from the first voltage application circuit (91) to the capacitor under inspection.

[0147] The inspection system (90) of the tenth aspect is any one of the first to ninth aspects, and further includes a current detection circuit (97) and an inspection circuit (98). The current detection circuit (97) detects a current flowing through the capacitor to be inspected. The inspection circuit (98) inspects the capacitor to be inspected based on the current detected by the current detection circuit (97).

[0148] According to this aspect, it is possible to inspect the capacitor under inspection based on the current flowing through the capacitor under inspection, and it is possible to determine whether the capacitor under inspection is good or bad.

[0149] In the inspection system (90) of the eleventh aspect, in the tenth aspect, the control circuit (93) applies the first voltage (V1) to the capacitor under test for a predetermined inspection period (T2) after stopping the application of the second voltage (V2) to the capacitor under test. The inspection circuit (98) inspects the capacitor under test based on the current detected during the inspection period (T2).

[0150] According to this aspect, it is possible to inspect the capacitor under inspection based on the current flowing through the capacitor under inspection during the inspection period (T2).

[0151] The inspection method of the twelfth aspect includes supplying an inrush current to the capacitor under test to charge the capacitor under test by applying a first voltage (V1) and a second voltage (V2) to the capacitor under test. The inspection method includes stopping the application of the second voltage (V2) to the capacitor under test before a voltage (V10) across the capacitor under test reaches the first voltage (V1) due to the supply of the inrush current. The second voltage (V2) is greater than the first voltage (V1).

[0152] According to this aspect, it is possible to supply a desired magnitude of inrush current to the capacitor under test. Also, while being able to supply a desired magnitude of inrush current, it is possible to prevent the capacitor under test from being charged to the first voltage (V1) or higher.

[0153] The manufacturing method of the thirteenth aspect includes a step of manufacturing a capacitor, and a step of inspecting the capacitor. The step of inspecting the capacitor is performed based on the inspection method of the twelfth aspect.

[0154] According to this aspect, it is possible to supply a desired magnitude of inrush current to the capacitor under test. Also, while being able to supply a desired magnitude of inrush current, it is possible to prevent the capacitor under test from being charged to the first voltage (V1) or higher. [Explanation of symbols]

[0155] 90 Inspection System 91 First voltage application circuit 912 1st Switch 92 Second voltage application circuit 921 2nd power supply (power supply) 922 Second Switch 923 Inrush Supply Capacitor 93 Control circuit 95 Discharge circuit 951 Discharge resistor 952 Discharge switch 96 Voltage measurement circuit 97 Current detection circuit 98 Inspection Circuit V1 First voltage V2 Second voltage V10 Voltage at both ends T2 Inspection Period Tr2 Second transistor

Claims

1. a first voltage application circuit that applies a first voltage to the test target capacitor; a second voltage application circuit that applies a second voltage higher than the first voltage to the test object capacitor; a control circuit that controls the first voltage application circuit and the second voltage application circuit so as to apply the first voltage and the second voltage to the capacitor under test to supply an inrush current to the capacitor under test to charge the capacitor under test, and to stop application of the second voltage to the capacitor under test before a voltage across the capacitor under test reaches the first voltage due to the supply of the inrush current; Equipped with the first voltage application circuit includes a first switch that switches on and off application of the first voltage to the test object capacitor; the second voltage application circuit includes a second switch that switches on and off application of the second voltage to the test target capacitor; The control circuit includes: by turning on the first switch and the second switch, the first voltage and the second voltage are applied to the test target capacitor; turning off the second switch before the voltage across the test target capacitor reaches the first voltage; the second switch comprises a transistor; when the control circuit turns on the first switch, a voltage supply source of the first voltage is connected to a base or a gate of the transistor, and when the control circuit turns on the first switch, the transistor is turned on by a voltage corresponding to a difference between an output voltage from the voltage supply source and the voltage across the test target capacitor. Inspection system.

2. The second voltage application circuit includes: Power supply, an inrush supply capacitor that is charged to the second voltage by the power supply and supplies the inrush current to the test target capacitor; Further comprising: The inspection system of claim 1 .

3. A discharge circuit for discharging the test target capacitor is further provided. the control circuit controls the discharge circuit to discharge the test target capacitor before the inrush current is supplied to the test target capacitor.

3. The inspection system according to claim 1 or 2.

4. The discharge circuit includes: A discharge resistor; a discharge switch that switches on and off a connection of the test target capacitor to the discharge resistor; Equipped with The control circuit discharges the test target capacitor by turning on the discharge switch. The inspection system of claim 3 .

5. The second voltage is 1.1 times or more the first voltage. The inspection system according to any one of claims 1 to 4.

6. the inrush current is greater than a current that can be supplied from the first voltage application circuit to the test target capacitor; The inspection system according to any one of claims 1 to 5.

7. a current detection circuit for detecting a current flowing through the test target capacitor; a test circuit for testing the test target capacitor based on the current detected by the current detection circuit; Further comprising: The inspection system according to any one of claims 1 to 6.

8. the control circuit applies the first voltage to the test target capacitor for a predetermined test period after stopping the application of the second voltage to the test target capacitor; The inspection circuit inspects the test target capacitor based on the current detected during the inspection period. The inspection system of claim 7.

9. applying a first voltage and a second voltage higher than the first voltage to a capacitor under test to supply an inrush current to the capacitor under test to charge the capacitor under test; stopping application of the second voltage to the test object capacitor before a voltage across the test object capacitor reaches the first voltage due to the supply of the inrush current; Including, a first voltage application circuit that applies the first voltage to the test target capacitor includes a first switch that switches on and off application of the first voltage to the test target capacitor; a second voltage application circuit that applies the second voltage to the test target capacitor includes a second switch that switches on and off application of the second voltage to the test target capacitor; charging the test target capacitor includes applying the first voltage and the second voltage to the test target capacitor by turning on the first switch and the second switch; stopping the application of the second voltage to the test target capacitor includes turning off the second switch before the voltage across the test target capacitor reaches the first voltage; the second switch comprises a transistor; When the first switch is turned on, a voltage supply source of the first voltage is connected to a base or a gate of the transistor, When the first switch is turned on, the transistor is turned on by a voltage corresponding to a difference between an output voltage from the voltage supply source and the voltage across the test target capacitor. Testing method.

10. manufacturing a capacitor; inspecting the capacitor according to the inspection method of claim 9; Including, Manufacturing method.

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