JP2010080558A - 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 inner pressure, a bent portion 35A of a lead wire 35 contacts a bent portion 36A of a lead wire 36. An electric current fuse F1 provided on the side of 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.

An electronic device according to claim 1 is an electronic circuit having a circuit component; a capacitor element containing an electrolytic solution; a case provided with a mouth portion for accommodating the capacitor element; And a pair of lead wires connected to the capacitor element and led out from the seal rubber, and the pair of lead wires is a region facing the seal rubber and is a seal rubber. In a state in which the sealing rubber does not bulge, each is provided with a bent portion provided so as to overlap each other when viewed from the sealing rubber side, and the bent portion is an electronic circuit component formed so as not to contact each other when the sealing rubber does not bulge And an electrolytic capacitor provided in the circuit.
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 pair of lead wires function to short-circuit one lead wire when the bent portions of each lead wire come into contact with each other. In such a state, the capacitor element does not act as a capacitor. To do.

  In addition, the shape of the bent portion of each lead wire is not particularly limited, and as long as it has a function of the present invention, it is in a form bent at an acute angle or a state bent in an arc shape, etc. Also good.

  Further, in the present invention, it is preferable that 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 bent portions of the pair of lead wires contact each other. Etc.). 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 invention of claim 1, since the pair of lead wires themselves are provided with a bent portion that short-circuits between the pair of lead wires connected to the capacitor element by the expansion of the sealing rubber, the life of the electrolytic capacitor The operation of the electronic circuit can be stopped before evaporating gas is generated at the end stage. Moreover, the function for preventing the evaporating gas at the end of the life of the electrolytic capacitor can be realized without increasing the number of parts.

  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 configured to have bent portions 35A and 36A between the sealing rubber 33 and the substrate 48, respectively.

  The bent portion 35A is formed on the lead wire 35 so as to be positioned in the vicinity of the sealing rubber 33 as shown in FIG. Also, the bent portion 36A is formed on the lead wire 36 so as to be positioned closer to the substrate 48 than the bent portion 35A of the lead wire 35 as shown in FIG. The bent portions 35A and 36A are provided so as to overlap each other when viewed from the sealing rubber 33 side as long as the sealing rubber 33 is a region facing the sealing rubber 33 and does not bulge. Further, the bent portions 35A and 36A are formed so as to have a height relationship so as not to contact each other when the sealing rubber does not bulge.

  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 bent portion 35A of the lead wire 35 provided in the vicinity of the seal rubber 33 starts to bend toward the substrate 48 due to the swelling of the seal rubber 33, and comes into contact with the bent portion 36A of the lead wire 36 when bent to some extent. . When the bent portions 35A, 36A come into contact, no current is supplied to the capacitor element inside the electrolytic capacitor C4, so the electrolytic capacitor C4 does not substantially function as a capacitor, and the main circuit loop 41 and An excessive current flows to 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.

  Further, even when the current fuse F1 is not provided, the bent portions 35A and 36A come into contact with each other and the storage circuit of the electrolytic capacitor C4 is cut off. As a result, an abnormal circuit operation is caused, 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 having the bent portions 35A and 36A in the pair of lead wires 35 and 36 so as to face the sealing rubber 33, the lighting lamp circuit 20 is caused by heat generated at the end of the life of the electrolytic capacitor C4. It is possible to reliably stop the operation by interrupting the operation. 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 addition, the number of parts does not increase in order to exhibit the function of preventing evaporated gas 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.

  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

Explanation of symbols

C4 ... Electrolytic capacitor, 20 ... Lighting circuit which is an electronic circuit, 35, 36 ... A pair of lead wires, 35A, 36A ... Bending portion of each lead wire

Claims (1)

An electronic circuit having circuit components;
A capacitor element containing an electrolyte, a case provided with a mouth portion for storing the capacitor element, a sealing rubber that seals the mouth portion of the case and bulges due to an increase in internal pressure in the case, and is connected to the capacitor element A pair of lead wires led out from the sealing rubber;
Each of the pair of lead wires includes a bent portion provided so as to overlap each other when viewed from the sealing rubber side in a state where the sealing rubber does not bulge and is a region facing the sealing rubber, and the bent portion is formed of the sealing rubber. An electrolytic capacitor provided in an electronic circuit as a circuit component formed so as not to contact each other in a non-bulged state;
An electronic apparatus comprising:

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