JP2010080559A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus in which an evaporation gas of an electrolyte is prevented from jetting to the outside when an electrolytic capacitor is at the end of its service life. <P>SOLUTION: When a temperature rises in a capacitor element, an inner pressure of a case 31 also suddenly changes, and when a sealing rubber 33 bulges toward a substrate 48 due to the change in the inner pressure, an anode contact point plate 35A contacts a cathode contact point plate 36A. An electric fuse F1 provided on a power supply e operates by an excessive current due to the contact and blows, thereby stopping a current to a lighting circuit 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an electronic device including an electronic circuit using an electrolytic capacitor.

  Conventionally, as an electronic device, for example, there is a lighting device that lights a discharge lamp. In this lighting device, a rectifier circuit, a boost chopper circuit, an inverter circuit, and the like are used. The step-up chopper circuit is configured such that an inductor and a switching element are connected to an output terminal of a rectifier circuit, and a series circuit of a diode and a smoothing electrolytic capacitor is connected in parallel to the switching element.

An electrolytic capacitor includes an electrolytic capacitor element and an electrolytic solution in which a pair of electrodes (foil) constituting an anode and a cathode are wound with a separator interposed therebetween in a bottomed cylindrical case having a mouth portion, for example. And the mouth of the case is sealed with a sealing rubber.
In electrolytic capacitors, the electrolytic solution evaporates and decreases with time, and at the end of the life, the electrolytic solution

In addition to a decrease in capacity due to the decrease in tan δ, an increase in tan δ occurs. Eventually, when the heat generation increases due to the ripple current and the heat dissipation cannot catch up, the temperature rapidly increases due to thermal runaway, and there is a possibility that the case may burst with the pressure of the evaporation gas of the electrolyte exceeding the boiling point of the electrolyte. Therefore, there is a case where a safety valve is provided in a part of the case, and when the pressure in the case reaches a predetermined pressure or more with the evaporation gas of the electrolyte, the safety valve is activated and the evaporation gas of the electrolyte is jetted to the outside. The case is prevented from bursting.

Also, changes in characteristics such as charging time, ripple current, and temperature of the electrolytic capacitor are detected by a special detection circuit on the circuit, and the life of the electrolytic capacitor is determined by the life determination circuit based on the detected characteristic change. There is a lighting device configured to do so (for example, see Patent Document 1).
JP 2006-236666 A (page 4-5, FIG. 1)

  In an electrolytic capacitor, the operation of a safety valve is a normal operation aimed at suppressing abnormal pressure rise in the case, but the evaporated gas of the electrolyte sprayed to the outside looks like smoke. Is easily misidentified as a fire.

  Further, in the lighting device that determines the life of the electrolytic capacitor, a detection circuit that detects a change in the characteristics of the electrolytic capacitor is separately provided on the circuit, but the characteristics of the electrolytic capacitor are indirectly detected. There is a possibility that the characteristics cannot be reliably detected due to the influence of a variable element such as noise on the circuit. In addition, since the life determining circuit for newly determining the life of the electrolytic capacitor based on the detected characteristic change is newly provided, the number of parts is increased, and the life determining circuit itself may be subject to secular change or abnormality. There is a problem that the life of the electrolytic capacitor cannot be accurately determined, and the circuit cannot be stopped.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic apparatus capable of suppressing the evaporation gas of the electrolytic solution from being ejected to the outside at the end of the life of the electrolytic capacitor.

The electronic device according to claim 1 is provided in an electronic circuit as a circuit component, and includes a capacitor element containing an electrolytic solution, a case provided with a mouth portion for storing the capacitor element, and a pair derived from a case connected to the capacitor element. An electrolytic capacitor having a sealing rubber that seals the mouth of the lead wire and the case and bulges due to an increase in internal pressure in the case; and is provided so as to face the sealing rubber, and the pair of Short-circuit means for short-circuiting between the lead wires.
In the present invention and the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.
The electronic circuit includes, for example, a light source lighting device and a motor driving device, but may be an electronic circuit used in other electronic devices.

  The circuit parts include circuit parts necessary for configuring an electronic circuit, such as capacitors such as electrolytic capacitors, winding parts such as chokes and inductors, and switching elements such as field effect transistors.

  The short-circuit means functions so that the action of the short-circuit means does not cause the capacitor element to act as a capacitor. This function works by the swelling of the sealing rubber, but is provided so as not to act when the sealing rubber is not bulged.

  Further, in the present invention, it is preferable to provide an overcurrent prevention means (for example, a current fuse) that functions to cut off the path of the electronic circuit by an overcurrent flowing through the electronic circuit when the short-circuit means functions. That is. By providing such an overcurrent prevention means, it is possible to reliably stop the operation of the electronic circuit, and in addition, malfunctions in circuit components and the like may occur due to overcurrent when the short-circuit means functions. Although it can be assumed, there is a possibility that an unexpected failure may occur, so that such an unexpected failure can be prevented.

  According to the first aspect of the present invention, it is provided so as to face the sealing rubber of the electrolytic capacitor, and has a short-circuit means for short-circuiting between the pair of lead wires connected to the capacitor element by the expansion of the sealing rubber. Thus, the operation of the electronic circuit can be stopped before evaporating gas is generated at the end of the life of the electrolytic capacitor.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 3 show a first embodiment, FIG. 1 is a circuit diagram of a lighting device showing a first embodiment of an electronic device, and FIG. 2 is an explanatory view showing an electrolytic capacitor of the lighting device. 3 is a partial cross-sectional view of a lighting fixture to which the lighting device is applied.

  As shown in FIG. 3, the lighting fixture 11 has a fixture main body 12, and a socket 13a and a lamp holder 13b are attached to the fixture main body 12. An annular fluorescent lamp as a light source is provided between the socket 13a and the lamp holder 13b. 14 is connected. A lighting device 15 as an electronic device for lighting the fluorescent lamp 14 is disposed in the fixture body 12.

  As shown in FIG. 1, in a lighting circuit 20 as an electronic circuit of the lighting device 15, a capacitor C1, a common mode choke Tr1, and a capacitor C2 constituting a filter circuit 21 are connected to a power source e through a fuse F1. The filter circuit 21 is connected to the input terminal of a full-wave rectifier circuit 22, the output terminal of the full-wave rectifier circuit 22 is connected to a capacitor C3, and the boost chopper circuit 23 is connected in parallel to the capacitor C3. Yes.

  The step-up chopper circuit 23 is connected to an inductor L1 and a field effect transistor Q1 as a switching element, and a series circuit of a diode D1 and a smoothing electrolytic capacitor C4 is connected in parallel to the field effect transistor Q1.

  An inverter circuit 25 is connected to the boost chopper circuit 23, and the inverter circuit 25 is connected in series with field effect transistors Q2 and Q3 as a pair of switching elements. A drive circuit 26 is connected to the gates of the field effect transistors Q2 and Q3, and the drive circuit 26 turns on and off the field effect transistor Q2 and the field effect transistor Q3 alternately. The drive circuit 26 is also connected to the gate of the field effect transistor Q1, and turns the field effect transistor Q1 on and off. The drive circuit 26 is controlled by a control circuit 27. The control circuit 27 detects the current and voltage of the lighting circuit 20, and controls the drive circuit 26 to start and light the fluorescent lamp 14.

  A series circuit of an inductor L2 and a resonance capacitor C6 is connected to the field effect transistor Q3 via a DC cut capacitor C5, and is connected to one end of each filament FL1, FL2 of the fluorescent lamp 14. A series circuit of filament preheating windings L3 and L4 magnetically coupled to the inductor L2 and preheating capacitors C7 and C8 are connected to the filaments FL1 and FL2, and a resonance circuit 28 is formed.

  Each circuit component 29 constituting the lighting circuit 20 is mounted on the substrate 48 as shown in FIG. The substrate 48 is a printed wiring board in which a conductive pattern is formed on an insulating substrate, and each circuit component 29 constituting the lighting circuit 20 connected to the pattern is mounted.

FIG. 2 shows an example of the electrolytic capacitor C4. The electrolytic capacitor C4 has a bottomed cylindrical shape having a mouth portion 31a. For example, a capacitor element and an electrolytic solution are placed in a case 31 made of aluminum, and a sealing rubber 33 is inserted into the mouth portion 31a of the case 31. 31a is sealed by sealing rubber 33. From the electrolytic capacitor C4, an anode side lead wire 35 and a cathode side lead wire 36 connected to a pair of electrodes of the internal electrolytic capacitor element are led out.
The anode-side lead 35 and the cathode-side lead wire 36 of the electrolytic capacitor C4 are provided with an anode-side contact plate 35A and a cathode-side contact plate 36A that are short-circuit means.

  Each of the contact plates 35A, 36A is formed in a conductive plate shape made of copper foil, and the anode side contact plate 35A is an anode so as to be disposed in the vicinity of the sealing rubber 33. It is fixed to the side lead wire 35. The cathode side contact plate 36A is fixed to the cathode side lead wire 36 so as to be disposed in the vicinity of the substrate 48 on which the electrolytic capacitor C4 is mounted.

  In addition, the anode side contact plate 35A and the cathode side contact plate 36A are in a height relationship such that they do not come into contact with each other when the sealing rubber 33 is not expanded, and when viewed from the sealing rubber 33 side, each contact plate 35A , 36A are provided so as to overlap each other.

  The operation of this embodiment will be described. First, the lighting circuit 20 is full-wave rectified by the full-wave rectifier circuit 22 through the filter circuit 21 when the power source e is turned on, and the field-effect transistor Q1 of the boost chopper circuit 23 is controlled by the drive circuit 26 to boost the voltage. Charge C4. The field effect transistors Q2 and Q3 are alternately turned on and off by the drive circuit 26, and the fluorescent lamp 14 is lit by supplying a high frequency voltage to the fluorescent lamp 14 by the voltage charged in the electrolytic capacitor C4.

  When the electrolytic capacitor C4 reaches the end of its life, the equivalent series resistance (ESR) increases due to a decrease in capacity due to a decrease in the electrolytic solution of the electrolytic capacitor C4, thereby increasing the temperature.

  In the state where heat generation and heat dissipation of this electrolytic capacitor C4 are uniform, the temperature rises slowly, but eventually heat generation increases due to ripple current, and when heat dissipation cannot catch up, thermal runaway occurs and the temperature rapidly increases Rises and evaporates beyond the boiling point of the electrolyte.

  When the temperature rises as described above, the internal pressure in the case 31 also changes abruptly. Therefore, the sealing rubber 33 bulges toward the substrate 48 with the change in the internal pressure. Then, the anode side contact plate 35A provided in the vicinity of the seal rubber 33 starts to bend toward the substrate 48 side due to the swelling of the seal rubber 33, and comes into contact with the cathode side contact plate 36A when bent to some extent. When the anode side contact plate 35A and the cathode side contact plate 36A come into contact with each other, no current is supplied to the capacitor element inside the electrolytic capacitor C4. Therefore, the electrolytic capacitor C4 does not substantially function as a capacitor. As a result, an excessive current flows to the main circuit loop 41 and the power source e side. Therefore, since the current fuse F1 provided on the power source e side is activated and blown by an excessive current (so-called short-circuit current), the current to the lighting circuit 20 is not supplied and the increase in the internal pressure of the electrolytic capacitor C4 is also stopped. It is possible to prevent the vapor gas from being ejected.

  The temperature at which the sealing rubber 33 starts to bulge may be adjusted according to whether or not the temperature of the electrolytic capacitor C4 at the end of the life (for example, about 150 ° C.) is reached, or the heat generation of the electrolytic capacitor C4 at the end of the life. The temperature at which the internal pressure is suddenly changed and the temperature rises from the state where the heat equalization with the heat radiation is taken may be used.

  Even if the current fuse F1 is not provided, the contact plates 35A, 36A come into contact with each other and the storage circuit of the electrolytic capacitor C4 is cut off. As a result, the circuit operation becomes abnormal, and the field effect transistor Q2 , Q3 is destroyed, so that the operation of the lighting circuit 20 can be stopped.

  In this way, by using the electrolytic capacitor C4 provided with the contact plates 35A and 36A so as to face the sealing rubber 33, the operation of the lighting lamp circuit 20 is surely cut off by the heat generated at the end of the life of the electrolytic capacitor C4. Can be stopped. Therefore, it is possible to prevent the evaporation gas of the electrolytic solution from being ejected to the outside at the end of the life of the electrolytic capacitor C4.

In the case of a circuit using a plurality of electrolytic capacitors, by using the electrolytic capacitor C4 as the electrolytic capacitor having the shortest lifetime, it is possible to reliably stop the operation of the circuit due to the lifetime of the electrolytic capacitor. In addition, the electrolytic capacitor of the present invention placed in a place where there is little fluctuation in the circuit may be used, and in such a place, the electrolytic capacitor is always used in the same state, so detection at the end of the life of the electrolytic capacitor Can be sure.
Next, a second embodiment will be described with reference to the drawings.
FIG. 4 is an explanatory diagram showing the configuration of the electrolytic capacitor and the short-circuit means of the second embodiment, and the description of the same reference numerals as those of the first embodiment is omitted.

  In the present embodiment, the difference from the first embodiment is that the ground side circuit pattern 36B of the lighting circuit 20 is disposed at a position facing the sealing rubber 33 of the electrolytic capacitor C4 instead of the cathode side contact plate 36A. is there.

  Even with this configuration, when the internal pressure in the case 31 changes abruptly and the sealing rubber 33 bulges to the substrate 48 side, the anode side contact plate 35A begins to bend toward the substrate 48 side, and if it is bent to some extent, It contacts the side circuit pattern 36B. When the anode-side contact plate 35A and the ground-side circuit pattern 36B come into contact with each other, no current is supplied to the capacitor element, so the electrolytic capacitor C4 does not substantially function as a capacitor, Excessive current will flow to the power source e side, and the subsequent functions will be substantially the same as in the first embodiment.

Therefore, also in the present embodiment, the operation of the lighting lamp circuit 20 can be shut off reliably by the heat generation at the end of the life of the electrolytic capacitor C4. Therefore, it is possible to prevent the evaporation gas of the electrolytic solution from being ejected to the outside at the end of the life of the electrolytic capacitor C4. Further, since the existing ground side circuit pattern 36B can be used, even if a function of short-circuiting the electrolytic capacitor C4 is added, the circuit can be implemented with a minimum structure.
Next, a third embodiment will be described with reference to the drawings.
FIG. 4 is an explanatory diagram showing the configuration of the electrolytic capacitor and the short-circuit means of the second embodiment, and the description of the same reference numerals as those of the first embodiment is omitted.

  In the present embodiment, as a difference from the first and second embodiments, the contact plates 35A and 36A are not provided, but the shapes of the anode side lead wire 35 and the cathode side lead wire 36 are devised, and each lead wire is provided. An axial jumper wire 40 for short-circuiting is provided between 35 and 36.

  Each lead wire 35, 36 has a bent portion 35C, 36C that is bent toward the center of the sealing rubber 33 at the intermediate portion thereof. The bent portions 35C and 36C are configured to be separated from each other even when viewed from the sealing rubber 33 side.

  The jumper wire 40 is mounted on the substrate 48, and is provided so as to face the sealing rubber 33 and the bent portions 35C, 36C. The length P of the jumper line is formed to be slightly longer than the interval T between the bent portions 35C and 36C.

  Then, according to the present embodiment, when the internal pressure in the case 31 changes suddenly and the sealing rubber 33 bulges to the substrate 48 side, the bent portions 35C and 36C of the lead wires 35 and 36 move to the substrate 48 side. The bends 35C and 36C and the jumper wire 40 come into contact with each other when the bend begins to bend to some extent. In such a state, since no current is supplied to the capacitor element inside the electrolytic capacitor C4, the electrolytic capacitor C4 does not substantially function as a capacitor, and the main circuit loop 41 and the power source e Excessive current flows to the side, and the subsequent functions are substantially the same as in the first and second embodiments.

  Therefore, also in this embodiment, the operation of the lighting lamp circuit 20 can be shut off reliably by the heat generated at the end of the life of the electrolytic capacitor C4. Therefore, it is possible to prevent the evaporation gas of the electrolytic solution from being ejected to the outside at the end of the life of the electrolytic capacitor C4.

  In each embodiment, the upper part of the electrolytic capacitor is described as an example that does not have a so-called safety valve that operates when the inside of the case becomes a predetermined pressure or more, but is limited to one that does not have a safety valve. It is also possible to combine the electrolytic capacitor having a safety valve with each of the present inventions. In such a combination, the short-circuit means of each embodiment is set to operate before the safety valve operates. It is a good thing.

Circuit diagram of lighting device showing first embodiment Explanatory drawing which showed the electrolytic capacitor and short circuit means of the lighting device of 1st embodiment Partial sectional drawing of the lighting fixture which applied the lighting device of 1st embodiment Explanatory drawing which showed the electrolytic capacitor and short circuit means of the lighting device of 2nd embodiment. Explanatory drawing which showed the electrolytic capacitor and short circuit means of the lighting device of 3rd embodiment.

Explanation of symbols

C4 ... electrolytic capacitor, 20 ... lighting circuit which is an electronic circuit, 35A, 36A ... contact plate for anode or cathode which is a short-circuit means

Claims (1)

An electronic circuit having circuit components;
Capacitor element that is provided in an electronic circuit as a circuit component, includes a capacitor element containing an electrolyte, a case provided with a mouth portion for containing the capacitor element, a pair of lead wires led out from the case connected to the capacitor element, and the mouth portion of the case is sealed And an electrolytic capacitor having a sealing rubber that expands due to an increase in internal pressure in the case;
A short-circuit means provided so as to face the sealing rubber and short-circuiting between the pair of lead wires by the swelling of the sealing rubber;
An electronic apparatus comprising:

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