JP2009117535A - Solid state relay and electronic device equipped with the same - Google Patents

Abstract

An object of the present invention is to provide a solid state relay excellent in maintainability of an electronic device and an electronic device including the same.
An optical coupling element comprising a light emitting element for converting an electrical signal into an optical signal and a light receiving element for converting an optical signal from the light emitting element into an electrical signal, and the optical coupling element and the optical coupling element on substantially the same plane. A triac element 1 for driving a load disposed in the package, a package resin portion (formed in region A) for resin-sealing the optical coupling element 2 and the triac element 1, and the optical coupling element 2 and the triac element 1 An electrode pad portion of a sixth lead frame 61 to which a frame having a plurality of lead terminals 11a, 21a, 31a, 41a, 51a electrically connected to the respective electrodes and a second electrode 1b of the triac element 1 are connected 61 P and the PTC element 3 connected in series between the electrode pad 21 b of the second lead frame 21 and sealed inside the package resin portion 4. That.
[Selection] Figure 2

Description

  The present invention relates to a solid-state relay having an overcurrent prevention structure and an electronic device equipped with the solid-state relay.

  As an example of a conventional solid state relay, a light emitting element such as a light emitting diode is provided on the input side, a power element for driving a load such as a triac element on the output side, and a triac element that receives light from the light emitting element is turned on. Some have a light receiving element such as a phototriac that arcs. An example of the internal structure of such a solid state relay is shown in FIG. FIG. 11 shows a state of the solid state relay before resin sealing in order to more clearly show the internal structure.

  The solid state relay includes a plurality of lead frames (first lead frame 111, second lead frame 121, third lead frame 131, fourth lead frame 141, and fifth lead frame) integrally formed on the tie bar portion 101a and the frame portion 101b. 151), the triac element 102 and the optical coupling element 103 are mounted on the frame. Further, the triac element 102 and the optical coupling element 103 are resin-sealed by a package resin portion (not shown) formed in a region A100 that includes element mounting portions or electrode pad portions of a plurality of lead frames.

  Although not shown, the first lead frame 111, the second lead frame 121, the third lead frame 131, the fourth lead frame 141, and the fifth lead frame 151 are cut by tie bar cutting after resin sealing. The tie bar portion 101a and the frame portion 101b connecting the lead terminals 111a, 121a, 131a, 141a, and 151a are removed. Further, these lead terminals 111a, 121a, 131a, 141a, 151a are subjected to lead forming as required depending on the shape of the finished product.

  When manufacturing such a solid state relay, first, the triac element 102 having the first electrode 102a on the bottom surface is fixed on the element mounting portion of the first lead frame 111 using a conductive paste or the like. In addition to being electrically connected, the second electrode 102b of the triac element 102 is electrically connected to the electrode pad portion of the second lead frame 121 via a wire, and the gate electrode 102c of the triac element 102 is connected to the third lead frame 131. The triac element 102 is mounted by being electrically connected to one electrode pad portion.

  Next, the first terminal 103 a of the optical coupling element 103 is electrically connected to the electrode pad part formed integrally with the element mounting part of the first lead frame 111. As a result, the first electrode 102a of the triac element 102 and the first terminal 103a of the optical coupling element 103 are electrically connected. Further, the second terminal 103b of the optical coupling element 103 is electrically connected to another electrode pad part integrally formed with one electrode pad part of the third lead frame 131, whereby the gate electrode 102c of the triac element 102 is obtained. Are electrically connected to the second terminal 103b of the optical coupling element 103. Furthermore, the third terminal 103 c of the optical coupling element 103 is electrically connected to the electrode pad portion of the fourth lead frame 141, and the third terminal 103 d of the optical coupling element 103 is electrically connected to the electrode pad portion of the fifth lead frame 151. Connect.

  Thereafter, although not shown, the triac element 102 and the optical coupling element 103 are separated from the element mounting portion and electrode pad portion of the first lead frame 111 and the electrode of the second lead frame 121 by the package resin portion formed in the region A100. The pad portion, the electrode pad portion of the third lead frame 131, the electrode pad portion of the fourth lead frame 141, and the entire electrode pad portion of the fifth lead frame 151 are sealed with resin. Finally, a solid state relay is obtained by performing tie bar cutting and lead forming.

  The optical coupling element 103 is formed by incorporating a light emitting diode and a phototriac into one package.

  In such a solid state relay, for example, when driving a motor load, a lead is connected in a state where the motor is connected in parallel between the lead terminal 111a of the first lead frame 111 and the lead terminal 121a of the second lead frame 121. The motor load was driven by passing a current between the terminal 111a and the lead terminal 121a.

  However, in such a solid-state relay, when an excessive current flows through the solid-state relay due to a short circuit of a load or the like, the triac element 102 generates heat, and a junction temperature (junction between semiconductor layers constituting the triac element 102) Temperature) may increase. This rise in junction temperature not only causes deterioration of characteristics and reliability, but also causes destruction or burning of the triac element 102, destruction or burning of an electronic device equipped with a solid state relay, and the like. was there.

In order to solve such a problem, there has been a solid state relay equipped with a fuse as a protection means when an overcurrent flows. Further, the semiconductor device and the lead frame disclosed in Japanese Patent Laid-Open No. 63-29564 and the power mold diode disclosed in Japanese Patent Laid-Open No. 8-111004 include the electrode of the power element in the solid state relay and the solid state diode. The wire connecting the lead terminal of the relay is configured to melt when an overcurrent flows.
JP-A-63-29564 Japanese Patent Laid-Open No. 8-11604

  According to a conventional solid state relay, in general, when an overcurrent flows due to a load short circuit or the like, it is possible to prevent destruction and burnout of a triac element constituting the solid state relay and an electronic device equipped with the solid state relay. However, since disconnecting the internal wiring path is a countermeasure against overcurrent, repair of circuit boards such as replacement of disconnected fuses and replacement of triac elements is also performed along with repair of parts of electronic equipment such as replacement of loads. There was a problem that it was necessary to carry out and that it took a lot of time and money to repair.

  On the other hand, in recent years, a polymer PTC thermistor called polymer PTC (positive temperature coefficient) has been used as a protective element for measures against overcurrent and overheating as performance is improved. This polymer PTC is used as a self-recoverable fuse that can be reset.

  The polymer PTC has a structure in which a polymer film mixed with conductive powder is sandwiched between two electrode foils, and lead terminals are attached to the electrode foils. This polymer PTC has a “positive temperature characteristic” in which the resistance value increases as the temperature rises. In other words, in the steady state, electricity flows through the conductive powder dispersed in the polymer, so that it has conductivity, and in a high temperature state, the polymer expands thermally, so that the distance between the electrode foils increases and the resistance value increases. To do. Therefore, by using this polymer PTC as a fuse of the circuit, the current flowing into the circuit can be limited by increasing the resistance value because the polymer PTC itself is overheated by the heat generated when the overcurrent flows. . Further, the resistance value of the polymer PTC is lowered again by returning the temperature of the polymer PTC by sufficiently lowering the voltage applied to the circuit or turning off the power supply. There is no need to replace after overcurrent interruption like overcurrent protection elements such as.

  However, when the polymer PTC is built in the solid state relay, the polymer PTC has a structure that detects the temperature change due to overcurrent and shuts off the overcurrent. Therefore, depending on the mounting position, the solid state relay itself operates normally. There is a case that the solid state relay cannot be adequately protected from overcurrent because it may be affected by heat generation due to the temperature change or a temperature change due to an increase in the ambient temperature of the electronic device.

  The present invention was devised to solve such problems, and an object of the present invention is to insert a PTC element formed using a polymer PTC in a package in a state of being connected in series with a power element, so that a solid state is obtained. An object of the present invention is to provide a solid state relay excellent in maintainability of an electronic device and an electronic device equipped with the same by preventing burning of the relay and the electronic device equipped with the solid state relay.

  In order to solve the above problems, a solid state relay of the present invention includes a light emitting element that converts an electrical signal into an optical signal and a light receiving element that converts an optical signal from the light emitting element into an electrical signal, as shown in FIG. The optical coupling element 2 provided, a triac element 1 as a load driving power element disposed on the same plane together with the optical coupling element 2, and a package for resin-sealing the optical coupling element 2 and the triac element 1 A resin portion (formed in region A), a frame including a plurality of lead terminals 11a, 21a, 31a, 41a, 51a electrically connected to the electrodes of the optical coupling element 2 and the triac element 1, Between the electrode pad portion 61b of the sixth lead frame 61 to which the second electrode 1b of the triac element 1 is connected and the electrode pad 21b of the second lead frame 21 are connected in series. And a connected PTC element 3. Further, the PTC element 3 is sealed inside the package resin portion 4.

  That is, when an overcurrent flows, the resistance value of the PTC element increases more quickly, so that the current limitation by the PTC element can be performed earlier and destruction of the triac element can be prevented. As a result, a solid state relay excellent in maintainability of electronic equipment can be obtained.

  Further, the PTC element is configured to cut off the current by changing the resistance value in 0.005 to 0.5 seconds when a current larger than the rated current of the power element flows. This is preferable because it can be surely prevented.

Moreover, the PTC element heat sink may be integrally formed at the PTC element connection portion of the frame, and the PTC element heat sink may be led out of the package resin portion. In this case, the heat generated in the periphery of the PTC element inside the package resin part can be radiated to the outside by the external heat radiating part. Further, the thermal resistance of the PTC element radiating plate causes the rated current of the power element to flow to the PTC element. When a current that is smaller than the rated current of the power element flows through the PTC element, the resistance value is changed in 0.005 to 0.5 seconds to cut off the current. The value within the range is preferable because the heat inside the package resin portion 4 can be excessively radiated to the outside by the external heat radiating portion 21c.

  Further, a lead terminal for a PTC element for taking out a change in resistance value of the PTC element to the outside may be provided. In this case, the amount of increase in the resistance value of the PTC element is taken out, and the amount of increase is fed back to the control side of the electronic device on which the solid state relay is mounted, thereby performing operation control such as limiting the output current. Can do.

  Further, a resistor may be mounted on the PTC element heat dissipation plate or the PTC element lead terminal, and the resistor may be connected in parallel to the PTC element. In this case, the resistance value of the PTC element mounted inside the package resin portion can be adjusted by the resistance voltage dividing ratio between the PTC element mounted inside the package resin portion and the external PTC element.

  In addition, an external heat dissipation plate fixed to the power element mounting portion of the frame is provided, the external heat dissipation plate is disposed on the surface of the package resin portion, and the PTC element heat dissipation plate or the PTC element lead terminal is provided. It may be bent along the surface of the package resin portion toward the opposite side of the surface of the package resin portion where the external heat sink is disposed. In this case, electrical insulation between the triac element and the PTC element 3 can be ensured.

  Further, a PTC element may be mounted on the PTC element heat sink or the PTC element lead terminal, and the PTC element may be connected in series to the PTC element sealed inside the package resin portion. Good. In this case, the output of the solid state relay can be cut off when excessive heat is generated around the solid state relay.

  The electronic device of the present invention is equipped with the above-described solid state relay.

  That is, when an overcurrent flows, the resistance value of the PTC element increases more quickly, so that the current limitation by the PTC element can be performed earlier and destruction of the triac element can be prevented. As a result, it is possible to obtain an electronic device with excellent maintainability using a solid state relay.

  Since the present invention is configured as described above, when an overcurrent flows, the resistance value of the PTC element can be increased more quickly, so that the current limitation by the PTC element can be performed earlier, and the triac element Can be prevented. As a result, it is possible to obtain a solid state relay excellent in maintainability of an electronic device and an electronic device equipped with the solid state relay.

  Hereinafter, embodiments of the solid state relay of the present invention and an electronic device equipped with the same will be described.

<Embodiment 1>
First, Embodiment 1 of the solid state relay of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an embodiment of the solid state relay of the present invention, and FIG. 2 is an explanatory view showing the internal structure of the solid state relay shown in FIG. FIG. 2 shows a state of the solid state relay before resin sealing.

  In this embodiment, the solid state relay is called a single in-line package in which a plurality of lead terminals (here, five lead terminals 11a, 21a, 31a, 41a, 51a) are led out from the bottom surface of the package resin portion 4. It is of a shape and is mainly used as a low power type to medium power type solid state relay.

  Further, the solid state relay has a light emitting diode as a light emitting element on the input side inside the package resin portion 4, and a load driving triac element 1 as a power element on the output side, and light of the light emitting element. And a phototriac as a light receiving element for receiving and igniting the triac element 1. Here, the optical coupling element 2 in which the light emitting diode and the phototriac are incorporated in one package is used. The first terminal 2a of the optical coupling element 2 is connected to one electrode of the phototriac, the second terminal 2b is connected to the other electrode of the phototriac, and the third terminal 2c is a light emitting diode. The fourth terminal 2d is connected to the other electrode of the light emitting diode.

  Furthermore, on one side surface of the package resin portion 4, an external heat radiating plate 5 is disposed for preventing deterioration in characteristics due to self-heating of the triac element 1.

  When this solid state relay is formed, a plurality of lead frames (first lead frame 11, second lead frame 21, third lead frame 31, fourth lead frame integrally formed with the tie bar portion 10a and the frame portion 10b are used. 41, a fifth lead frame 51, and a sixth lead frame 61). On the frame, the triac element 1, the optical coupling element 2, and a PTC element 3 formed using a polymer PTC are mounted. Further, the triac element 1, the optical coupling element 2 and the PTC element 3 are sealed together with the element mounting portion and the electrode pad portion of the frame by the package resin portion 4 (see FIG. 1) formed in the region A in FIG. It has been stopped.

  Further, after the resin sealing, the lead terminals 11a of the first lead frame 11, the second lead frame 21, the third lead frame 31, the fourth lead frame 41, and the fifth lead frame 51 are cut by tie bar cutting. The tie bar portion 10a and the frame portion 10b connecting the portions 21a, 31a, 41a, 51a and the extension portion 61a of the sixth lead frame 61 are removed. Furthermore, although not implemented in the present embodiment, the lead terminals 11a, 21a, 31a, 41a, 51a are subjected to lead forming as necessary depending on the shape of the finished product.

  When manufacturing such a solid state relay, first, the element mounting portion 11b of the first lead frame 11, the electrode pad portion 11c integrally formed with the element mounting portion 11b, and the electrode of the second lead frame 21 are firstly formed. The electrode part of the pad part 21b, the first electrode pad part 31b of the third lead frame 31, the electrode pad part 41b of the fourth lead frame 41, the electrode pad part 51b of the fifth lead frame 51, and the electrode of the sixth lead frame 61 A conductive paste is applied to each pad portion 61b. Further, the triac element 1 having the first electrode 1a on the bottom surface is arranged on the element mounting part 11b, the first terminal 2a of the optical coupling element 2 is arranged on the electrode pad part 11c, and the electrode pad part 21b One electrode 3a of the PTC element 3 is disposed on the electrode pad portion 31b, the second terminal 2b of the optical coupling element 2 is disposed on the electrode pad portion 31b, and the third terminal 2c of the optical coupling element 2 is disposed on the electrode pad portion 41b. Then, with the fourth terminal 2d of the optical coupling element 2 disposed on the electrode pad portion 51b and the other electrode 3b of the PTC element 3 disposed on the electrode pad portion 61b, reflow soldering was performed, and the conductive paste was applied. Heat cure.

  Next, the second electrode 1b of the triac element 1 is electrically connected to the electrode pad portion 61b of the sixth lead frame 61 via the wires 20a and 20b, and the second electrode 1b of the triac element 1 and the second lead frame 21 are connected. The PTC element 3 is connected in series with the lead terminal 21a. Further, the gate electrode 1 c of the triac element 1 is electrically connected to the second electrode pad portion 31 c of the third lead frame 31 through the wire 20 c.

  Thereafter, the triac element 1, the optical coupling element 2, and the PTC element 3 are connected to the element mounting portion 11b, the electrode pad portion 11c, and the second lead frame 21 of the first lead frame 11 by the package resin portion 4 formed in the region A. Resin-sealed together with the electrode pad portion 21b, the first electrode pad portion 31b and the second electrode pad portion 31c of the third lead frame 31, the electrode pad portion 41b of the fourth lead frame 41, and the electrode pad portion 51b of the fifth lead frame 51 Stop.

  In order to prevent deterioration in characteristics due to self-heating of the triac element 1, the element mounting portion 11b of the first lead frame 11 has a large area, and the external heat sink 5 is fixed to the element mounting portion 11b later. A heat sink mounting hole 11b1 is formed. Furthermore, a through hole (or recess) (not shown) communicating with the heat sink mounting hole 11b1 is formed in the package resin portion 4, and the heat sink mounting hole 11b1 is covered with the package resin portion 4 even after resin sealing. It is in an exposed state.

  Finally, after performing tie bar cutting and lead forming as necessary, the heat radiating plate is provided with a heat radiating plate mounting hole 11b1 and an external heat radiating plate 5 having a shape that fits into the through hole (or concave portion). The convex portion is attached to the side surface of the package resin portion 4 by press-inserting the convex portion into the mounting hole 11b1 and the through hole (or concave portion). The external heat radiating plate 5 can radiate the heat inside the package resin portion 4 generated by the self-heating of the triac element 1 to the outside.

  When the PTC element 3 is mounted in the form as in the present embodiment, it is preferable to use a surface mount type as the PTC element 3, and in particular, an element having heat resistance enough to withstand reflow soldering is used.

  In the present embodiment, since the PTC element 3 is connected in series to the triac element 1, that is, the power element, a steady current flows through the PTC element 3 in a normal state. Then, when an overcurrent flows due to a load short circuit or the like, heat generation of the power element is also superimposed, and the resistance value of the PTC element 3 rises earlier, and current limitation by the PTC element 3 is performed. The destruction of the triac element can be prevented. As a result, it is possible to prevent destruction of the solid state relay and the electronic device equipped with the solid state relay. Further, since the PTC element 3 is a self-returning element, the electronic device can be repaired by removing main causes such as load replacement. Therefore, the burden (time and cost) necessary for maintenance and repair of the electronic device is reduced.

  In general, a state in which the polymer PTC has a high resistance and restricts (or cuts off) the current flowing through the PTC element is called “tripping”, and it is necessary to change from a normal state to a tripping state. Time is called trip time. In this embodiment, in order to protect the solid state relay, it is desirable that the length of the trip time is about 0.005 to 0.5 S (seconds).

  FIG. 3 is a graph showing an example of the operating characteristics of the PTC element constituting the solid state relay shown in FIG.

  For example, when the maximum rated current (IT) of the effective on-current of the solid state relay is IT = 4 A (ampere) and the current withstand amount of the power element is 10 A, the breaking current as shown in FIG. -It is desirable to use one having a trip time characteristic. This is because in a steady state, a sufficient operating current can be secured, and when an overcurrent that destroys the power element flows, the overcurrent is instantaneously interrupted.

<Embodiment 2>
Next, Embodiment 2 of the solid state relay of the present invention will be described with reference to the drawings.

  FIG. 4 is an explanatory view showing Embodiment 2 of the solid state relay of the present invention, showing the state of the solid state relay before resin sealing. 5 is a bottom view showing an example of the external heat dissipating part constituting the solid state relay shown in FIG. 4, and FIG. 6 is another example of the external heat dissipating part constituting the solid state relay shown in FIG. It is a bottom view shown.

  Generally, when a solid state relay is mounted on a board and used, heat may be easily accumulated depending on the mounting position. In the solid state relay shown in the first embodiment, as shown in FIG. 2, the external heat sink 5 prevents performance degradation due to self-heating, but this external heat sink 5 is connected to the element mounting portion 11b. Therefore, the effect of providing the external heat sink 5 is obtained for the PTC element 3 connected in series to the element mounting portion 11b via the triac element 1, the wires 20a and 20b, and the electrode pad 61b. There may not be. In this case, only the PTC element 3 rises in temperature and may become high resistance and interrupt current.

  In the present embodiment, as shown in FIG. 4, an external heat radiating portion 21c is integrally formed with the electrode pad portion 21b to which one electrode 3a of the PTC element 3 is connected. As shown in FIG. 5, the external heat radiating portion 21c is not covered by the package resin portion 4 during resin sealing, and is led out from the side surface of the package resin portion 4 after resin sealing. Since it has such a structure, according to the solid state relay of this embodiment, the heat generated in the periphery of the PTC element 3 inside the package resin portion 4 can be radiated to the outside by the external heat radiating portion 21c.

  In addition, if the heat inside the package resin portion 4 is excessively radiated to the outside by the external heat radiating portion 21c, a phenomenon that a trip cannot be caused at an overcurrent occurs. In order to prevent such a phenomenon, the size of the external heat radiating portion 21c needs to be determined in consideration of the thermal resistance of the external heat radiating portion 21c. Furthermore, when there is a surplus in the withstand current amount of the power element with respect to the maximum rated current of the effective on-current of the solid state relay, only the lead terminal 21a of the second lead frame 21 without forming the external heat radiating portion 21c, In some cases, the heat generated in the PTC element 3 can be sufficiently dissipated from the inside of the package resin portion 4 to the outside.

  In addition, it is necessary to ensure electrical insulation between the external heat radiation plate 5 electrically connected to the triac element 1 and the external heat radiation portion 21c electrically connected to the PTC element 3. Therefore, although not shown, the external heat radiation part 21c is formed in the same lead shape as each lead terminal, and when the solid state relay is mounted on the board, the lower end part of the external heat radiation part 21c is formed on the board at the same time. The space between the external heat sink 5 and each lead terminal may be secured by inserting and fixing in the holes. Moreover, as shown in FIG. 6, you may bend the external thermal radiation part 21c in the direction shown by the arrow C on the opposite side to the external heat sink 5 attachment position along the package resin part 4 side surface.

<Embodiment 3>
Next, Embodiment 3 of the solid state relay of the present invention will be described with reference to the drawings.

  FIG. 7 is an explanatory view showing Embodiment 3 of the solid state relay of the present invention, and shows a state of the solid state relay before resin sealing.

  In the solid state relay of the present embodiment, the lead for the PTC element is connected to the electrode pad part 21b to which one electrode of the PTC element 3 is connected and the electrode pad part 61b to which the other electrode of the PTC element 3 is connected. Terminals 21d and 61c are integrally formed.

  These PTC element lead terminals 21 d and 61 c are formed to measure the resistance value of the PTC element 3. The resistance value of the PTC element 3 can also be measured by using lead terminals derived from the bottom surface of the package resin portion 4, but since an operating current flows through each lead terminal, a method of providing a dedicated lead terminal Can accurately measure the resistance value.

  In general, the resistance value of the PTC element 3 also increases when a current lower than the cutoff current flows. According to the solid state relay of the present embodiment, since the lead terminals for the PTC element 21d and 61c are provided, the increase amount of the resistance value of the PTC element 3 is taken out using the lead terminals for the PTC element 21d and 61c. By feeding back the increased amount to the control side of the electronic device on which the solid state relay is mounted, it is possible to perform operation control such as limiting the output current with a microcomputer (microcomputer), for example. In this case, when a PTC element that reacts too quickly until the trip time in the low current region is used, the trip occurs in the low current region before the control of the microcomputer. Therefore, here, it is necessary to use a PTC element having a steep slope of the breaking current-trip time characteristic.

  Further, the lead terminals 21d and 61c for the PTC element may be used as an external heat radiating portion as in the solid state relay of the second embodiment with a large surface area.

<Embodiment 4>
Next, a fourth embodiment of the solid state relay of the present invention will be described with reference to the drawings.

  FIG. 8 is an explanatory diagram showing an example of the fourth embodiment of the solid state relay of the present invention, and FIG. 9 is an explanatory diagram showing another example of the fourth embodiment of the solid state relay of the present invention. 8 and 9 show a state of the solid state relay before resin sealing.

  Compared with the solid state relays of the first to third embodiments described above, the solid state relay of the present embodiment is a resistor connected in parallel to the PTC element 3 mounted inside the package resin portion 4 outside the package resin portion 4. The difference is that an external PTC element 30 is provided.

  In the solid state relay shown in FIG. 8, the electrode for resistance connection is connected to the electrode pad portion 21b to which one electrode of the PTC element 3 is connected and the electrode pad portion 61b to which the other electrode of the PTC element 3 is connected. Pad portions 21e and 61d are integrally formed. Furthermore, one electrode 30a of the external PTC element 30 is connected to the electrode pad portion 21e for resistance connection, and the other electrode 30b of the external PTC element 30 is connected to the electrode pad portion 61d for resistance connection.

  Further, in the solid state relay shown in FIG. 9, the electrode pad portion 21 b to which one electrode of the PTC element 3 is connected and the other electrode of the PTC element 3 are connected as in the solid state relay shown in FIG. 7. Relay-shaped resistance connection lead terminals 21f and 61e are integrally formed with the electrode pad portion 61b. Furthermore, in the present embodiment, one electrode 30a of the external PTC element 30 is connected to the resistance connection lead terminal 21f, and the other electrode 30b of the external PTC element 30 is connected to the resistance connection lead terminal 61e. Yes.

  When the PTC element 3 is mounted inside the package resin portion 4 as in the solid state relays of the first to third embodiments described above, the resistance value of the PTC element 3 cannot be adjusted after resin sealing. According to the solid state relay of the present embodiment, by mounting the external PTC element 30 as a resistance outside the package resin portion 4, the resistance component between the PTC element 3 mounted inside the package resin portion 4 and the external PTC element 30. The resistance value of the PTC element 3 mounted inside the package resin portion 4 can be adjusted by the pressure ratio.

  However, in such a configuration, a large current may flow when the PTC element 3 arranged inside the package resin portion 4 becomes high resistance, so pay attention to the current resistance of the solid state relay. Also, it is necessary to pay attention to the wattage (power consumption) of the PTC element 3 itself mounted inside the package resin portion 4.

<Embodiment 5>
Next, Embodiment 5 of the solid state relay of the present invention will be described with reference to the drawings.

  FIG. 10 is an explanatory view showing Embodiment 5 of the solid state relay of the present invention, showing the state of the solid state relay before resin sealing.

  When manufacturing the solid state relay of this embodiment, as a frame, an electrode pad to which the first lead frame 11 to which the first electrode 1a of the triac element 1 is connected and one electrode of the PTC element 3 is connected. A part in which relay-shaped external PTC element connecting lead terminals 11d and 21f are integrally formed with the part 21b is used. One electrode 31a of the external PTC element 31 is connected to the external PTC element connection lead terminal 21f, and the other electrode 31b of the external PTC element 31 is connected to the external PTC element connection lead terminal 11d. . Further, when mounting the solid state relay on the board, after fixing the lower ends of the external PTC element connecting lead terminals 11d and 21f to the board, respectively, for example, by cutting the positions indicated by the broken lines B1 and B2 in the figure The lead terminal 11d for connecting an external PTC element is separated from the first lead frame 11. That is, not only the PTC element 3 mounted in the package resin portion 4 but also the external PTC element 31 connected in series to the PTC element 3 is mounted on the solid state relay of the present embodiment.

  With this configuration, according to the solid state relay of this embodiment, the output of the solid state relay can be cut off when excessive heat is generated around the solid state relay. In the present embodiment, considering the derating of the solid state relay (reduction of the cause of failure) as the external PTC element, the current amount at the maximum operating temperature is mounted on the solid state relay itself or this solid state relay. Those having characteristics that are less than or equal to the withstand current of the electronic device are selected.

  Moreover, since the electronic device of the present invention is equipped with any one of the solid state relays shown in the above-described first to fifth embodiments, the electronic device can be prevented from being burned out.

  The solid state relay of the present invention and an electronic device equipped with the solid state relay can be used when it is difficult to replace the relay after the overcurrent is interrupted, or when the time and cost for repair are reduced.

It is a perspective view which shows one Embodiment of the solid state relay of this invention. It is explanatory drawing which shows the internal structure of the solid state relay shown in FIG. It is a graph which shows an example of the operation characteristic of the PTC element which comprises the solid state relay shown in FIG. It is explanatory drawing which shows Embodiment 2 of the solid state relay of this invention. It is a bottom view which shows an example of the external thermal radiation part which comprises the solid state relay shown in FIG. It is a bottom view which shows the other example of the external thermal radiation part which comprises the solid state relay shown in FIG. It is explanatory drawing which shows Embodiment 3 of the solid state relay of this invention. It is explanatory drawing which shows one Example of Embodiment 4 of the solid state relay of this invention. It is explanatory drawing which shows the other Example of Embodiment 4 of the solid state relay of this invention. It is explanatory drawing which shows Embodiment 5 of the solid state relay of this invention. It is explanatory drawing which shows the example of an internal structure of the conventional solid state relay.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Triac element 2 Optical coupling element 3 PTC element 4 Package resin part 5 External heat sink 10a Tie bar part 10b Frame part 11 First lead frame 11a Lead terminal 21 Second lead frame 21a Lead terminal 31 Third lead frame 31a Lead terminal 41 First 4 lead frame 41a Lead terminal 51 5th lead frame 51a Lead terminal 61 6th lead frame 30 External PTC element

Claims (9)

An optical coupling element including a light emitting element that converts an electrical signal into an optical signal and a light receiving element that converts an optical signal from the light emitting element into an electrical signal, and a load drive disposed on the same plane together with the optical coupling element Power element, a package resin portion for resin-sealing the optical coupling element and the power element, and a frame including a plurality of lead terminals electrically connected to the electrodes of the optical coupling element and the power element A configured solid state relay,
A PTC element connected in series is mounted between one electrode of the power element and the lead terminal by being electrically connected to the frame, and the PTC element is sealed inside the package resin portion. Solid-state relay characterized by   2. The solid state relay according to claim 1, wherein the PTC element changes the resistance value in 0.005 to 0.5 seconds when a current larger than the rated current of the power element flows. Solid state relay that is to be cut off.   3. The solid state relay according to claim 1, wherein a PTC element heat sink is integrally formed at a PTC element connection portion of the frame, and the PTC element heat sink is led out of the package resin portion. Solid state relay.   4. The solid state relay according to claim 3, wherein a thermal resistance of the heat dissipation plate for the PTC element is a value at which a current smaller than a rated current of a power element flows through the PTC element, and a power element is connected to the PTC element. Solid state relay that is in the range of cutting off the current by changing the resistance value in 0.005 to 0.5 seconds when a current larger than the rated current of.   The solid state relay according to claim 1, 2, or 3, further comprising a lead terminal for a PTC element for taking out a change in resistance value of the PTC element to the outside.   6. The solid state relay according to claim 3, 4 or 5, wherein a resistor is mounted on the PTC element heat sink or the lead terminal for the PTC element, and the resistor is connected in parallel to the PTC element. relay.   7. The solid state relay according to claim 3, further comprising an external heat sink fixed to the power element mounting portion of the frame, wherein the external heat sink is disposed on the surface of the package resin portion. The solid where the heat dissipation plate for the PTC element or the lead terminal for the PTC element is bent along the surface of the package resin portion toward the side opposite to the portion where the external heat dissipation plate is disposed on the surface of the package resin portion. State relay.   6. The solid state relay according to claim 3, 4 or 5, wherein a PTC element is mounted on the PTC element heat dissipation plate or the lead terminal for the PTC element, and the PTC element is sealed inside the package resin portion. Solid state relay connected in series with PTC element.   The electronic device carrying the solid state relay of any one of Claims 1-8.

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