JP2005039948A - Semiconductor device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent the overheat of a main element by accurately detecting the temperature of the main element constituting a semiconductor device that controls an AC load. <P>SOLUTION: The semiconductor device is configured such that: an overheat detection part composed of an element having a positive temperature characteristic is arranged at a gate of the main element that constitutes the semiconductor device; the temperature of the main element is directly detected by the overheat detection part; and a gate signal is blocked so that the temperature of the main element does not reach the junction temperature of the element. By this configuration, the main element is prevented from being broken by the overheat without the need for using a complicated circuit constitution. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductor device that controls an AC load, such as an AC fan motor such as an air conditioner or an oil fan heater, an AC lamp such as a copying machine, and an electronic device including the semiconductor device for AC load control.

  2. Description of the Related Art As a semiconductor device having an overheat cutoff function in a gate control unit of a main element constituting a semiconductor device, a semiconductor device using a diode or the like for the device itself and having an overheat cutoff function is known as a semiconductor device for controlling a DC load. ing.

  On the other hand, in a semiconductor device that controls an AC load, a method of detecting a temperature abnormality of the device by using a current limiting element such as a thermistor on a circuit is known.

  Specifically, for example, in order to prevent thermal destruction of the thyristor, the thermal thyristor is fixed to the cooling fin of the thyristor, and the thermal thyristor is inserted between the gate and the cathode of the thyristor. A method for protecting a thyristor that automatically shuts off the gate signal is proposed (for example, see Patent Document 1).

  Also proposed is a method of protecting the optical coupling element by connecting a resistance element (thermal element) having a positive or negative temperature coefficient to the input side (light receiving element side) or output side (light emitting element side). (For example, see Patent Document 2).

Furthermore, as a semiconductor device having a temperature detection function, a semiconductor device in which a thermal element for detecting a temperature state of a semiconductor chip is arranged in a semiconductor element formation region has been proposed (for example, see Patent Document 3). .
Japanese Utility Model Publication No. 58-70095 JP-A-8-186285 JP-A-10-116987

  However, the techniques described in Patent Documents 1 to 3 have the following problems.

  First, in the thyristor protection method described in Patent Document 1, in order to prevent thermal destruction of the thyristor, a thermal thyristor fixed to the cooling fin of the thyristor is inserted between the gate and the cathode of the thyristor so that the thyristor is at a predetermined temperature or higher. In this case, the gate signal to the thyristor is automatically shut off. To shut off the gate signal to the thyristor with the thermal thyristor, it is necessary to take measures such as malfunction of the thermal thyristor. For this reason, it is necessary to design the circuit including a protection circuit and the like, which complicates the structure. In addition, it is necessary to select a thermal thyristor that has specifications that match the gate sensitivity of the thyristor and that considers heat conduction to the cooling fins. Furthermore, since the heat-sensitive thyristor itself generates heat due to heat, it is necessary to design in consideration of changes in the gate sensitivity of the thyristor.

  The technique described in Patent Document 2 is intended to protect the optical coupling element from overheating by using a resistance element having a positive or negative temperature coefficient in the optical coupling element, and a simple circuit configuration. Although it is possible to use a thermal element arranged at a position away from the main heating element in a circuit, there is a problem that it is difficult to design a protection temperature.

  Patent Document 3 describes that a thermal element for detecting the temperature condition of a semiconductor chip is arranged. The target semiconductor element is an element for controlling a DC load such as a bipolar transistor or a power IC. No proposal has been made regarding an AC load control element.

  The present invention has been made in view of such circumstances, and can accurately detect the temperature of the main element constituting the semiconductor device that controls the AC load with a simple configuration. It is an object of the present invention to provide a semiconductor device capable of reliably preventing overheating and an electronic device including such a semiconductor device.

  A semiconductor device of the present invention is a device that controls an AC load, and includes an overheat detection unit that detects a temperature of a main element constituting the semiconductor device during operation of the device, and the overheat detection unit has a positive temperature characteristic. An element, and is configured to block the gate signal of the main element when the temperature of the main element reaches a set temperature (for example, a temperature lower than a junction temperature of the element by a predetermined amount). Yes.

  In the semiconductor device according to the present invention, the overheat detecting portion may be fixed to the gate portion of the main element with a high thermal conductive paste or solder, or a groove provided in the gate portion of the main element. It may be formed inside. Further, as the overheat detection unit, a thermistor made of a conductive polymer having a positive temperature characteristic may be used.

  In the semiconductor device of the present invention, examples of the main element include a thyristor or a triac.

  A specific configuration of the semiconductor device according to the present invention includes a first triac having an output terminal and a gate terminal, and a second triac having an output terminal and a gate terminal, and one of the output terminals of the first triac. One example is a solid state relay that is connected to the gate terminal of the second triac. In this case, the overheat detection unit may be provided in the second triac.

  The electronic apparatus of the present invention is characterized by including the semiconductor device having the above characteristics. Specific examples of electronic devices include home appliances such as air conditioners and oil fan heaters, and OA devices such as copiers, but are not limited thereto, and any device having an AC load may be used. The present invention can also be applied to any other kind of electronic equipment.

  The semiconductor device of the present invention is a device for controlling an AC load, and an overheat detection unit including a thermistor having a negative temperature characteristic is provided in a gate portion of a main element constituting the semiconductor device. An overheat protection function for detecting the temperature of the main element by the detection unit and controlling the gate signal of the main element is provided.

  In the semiconductor device of the present invention, examples of the main element include a thyristor or a triac.

  An electronic apparatus including the semiconductor device having such a feature is also included in the present invention. In the case of this electronic apparatus, an overheat protection function is provided by configuring the thermal fuse to be blown when the main element is overheated. In addition, specific examples of the electronic device include electronic appliances such as an air conditioner and an oil fan heater, and OA devices such as a copying machine, but are not limited thereto, and have an AC load. If so, the present invention can be applied to other arbitrary types of electronic devices.

  According to the present invention, since the overheat detection unit made of an element having a positive temperature characteristic is provided in the gate part of the main element constituting the semiconductor device, the temperature of the main element can be detected with a simple configuration with high accuracy. Can do. In the present invention, the temperature of the main element is directly detected by the overheat detection unit, and the gate signal is blocked so that the temperature of the main element does not become the junction temperature of the element. It becomes possible to protect against destruction. Therefore, by using a semiconductor device having such characteristics for an electronic device, the electronic device can have an overheat protection function.

  In addition, according to the present invention, an overheat detection unit comprising a thermistor having a negative temperature characteristic is provided at the gate of the main element constituting the semiconductor device, and the temperature of the main element is directly detected by the overheat detection unit. Since the gate signal of the main element is controlled, a protective semiconductor device having an overheat cutoff function having a positive temperature characteristic that the apparatus operates when the temperature of the main element becomes abnormal is provided. Can be provided. And by applying such a semiconductor device to an electronic device, the fuse of the electronic device can be surely blown, and the electronic device can be protected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, an example of a solid state relay (SSR), which is one of semiconductor devices that control an AC load, will be described with reference to FIG.

  The solid state relay 1 of FIG. 1 is provided with an infrared light emitting diode 4 as a light emitting element on the input side, and a photo triac 3 for receiving light from the infrared light emitting diode 4 and a driving main triac 2 on the output side. Is provided. The resistor 5 and the capacitor 6 connected in parallel to the output side of the solid state relay 1 are elements constituting a noise absorption circuit.

  In the solid state relay 1 having this structure, when an input current is passed to the input side, the infrared light emitting diode 4 emits light, and the phototriac 3 is turned on by the light, and a current flows to the gate of the main triac 2 at the next stage. Since the main triac 2 is mainly connected to an AC power supply, the gate current also becomes a “+” or “−” signal. When a current flows through the gate of the main triac 2, the main triac 2 is triggered, the main triac 2 is turned on, and the main triac 2 is turned on, so that the electrons connected to the output side of the solid state relay 1 The device load (AC load) is controlled.

  In the solid state relay 1 that operates in this manner, the main triac 2 that is the main element generates heat, and therefore, it is necessary to control the temperature to be equal to or lower than the junction temperature of the element.

  Therefore, in the present invention, an overheat detection part is formed in the gate part of the driving main triac, which is the main element of the solid state relay (semiconductor device), so that the temperature of the main triac is higher than the set temperature (for example, the junction temperature of the element). It is characterized in that the main triac is protected from thermal destruction by blocking the gate signal to the gate electrode of the main triac when the temperature is lower by a predetermined amount.

  Examples of the overheat detection unit used for such overheat cutoff control include a thermistor having a positive temperature characteristic as illustrated in FIG. 7 or a thermistor having a negative temperature characteristic as illustrated in FIG. .

  When a thermistor having a positive temperature characteristic is used as the overheat detector, the overheat detector S1 is provided in series with the triac gate as shown in the equivalent circuit of FIG. The gate signal can be cut off so that the temperature of the main triac 2 as the main element does not become the junction temperature of the element. The case where a thermistor having a negative temperature characteristic is used as the overheat sensing unit will be described later.

  Next, a specific configuration (Configuration Example 1 and Configuration Example 2) of the driving main triac used as the main element of the solid state relay is shown below.

<Configuration example 1>
In the main triac, as shown in FIG. 3, a T1 electrode (cathode electrode) 11, a gate electrode 13, and a T2 electrode (anode electrode) 12 are formed on the upper and lower surfaces of a semiconductor chip 10 having an NPNPN five-layer structure, respectively. The device has a configuration in which two reverse blocking thyristors are connected in reverse parallel. The shape and arrangement of the T1 electrode 11 and the gate electrode 13 on one side of the semiconductor chip 10 are as shown in the plan view of FIG.

  In this example, a thermistor 14 (for example, made of a conductive polymer) having a positive temperature characteristic (see FIG. 7) is used as the overheat detection unit S1 shown in FIG. 2, and the thermistor 14 is used as the gate electrode of the main triac 2. 13 is characterized in that it is fixed on the surface 13 using a paste or solder having high thermal conductivity.

  Thus, by fixing the thermistor 14 on the gate electrode 13 with paste or solder, the temperature of the main triac 2 can be detected with high accuracy without any heat loss.

<Configuration example 2>
The main triac in this example is basically the same as <Structure Example 1> described above. As shown in FIG. 4, T1 electrodes (cathodes) are respectively formed on the upper and lower surfaces of the semiconductor chip 20 having an NPNPN five-layer structure. Electrode) 11 and gate electrode 13 and T2 electrode (anode electrode) 12 are formed. Note that the shape and arrangement of the T1 electrode 11 and the gate electrode 13 on one side of the semiconductor chip 20 are similarly as shown in the plan view of FIG.

  In this example, the thermistor 24 made of a conductive polymer having a positive temperature characteristic is embedded in the lower layer of the gate electrode 13 of the main triac 2. The thermistor 24 is formed in the groove 20 a processed in the gate portion of the semiconductor chip 20.

  Also in this example, an equivalent circuit as shown in FIG. 2 is formed. In addition, the temperature of the main triac 2 can be detected directly, and highly accurate temperature detection becomes possible.

  In the structure shown in FIG. 4, for example, as shown in FIG. 6, for example, a semiconductor chip 20 having a five-layer structure is first manufactured (FIG. 6A). Next, a groove (mesa groove) 20a is processed by etching in the gate portion of the semiconductor chip 20 (FIG. 6B), and the inside of the groove 20a is filled with a conductive polymer having a positive temperature characteristic. The thermistor 24 is formed (FIG. 6C). Then, the T1 electrode (cathode electrode) 11, the gate electrode 13, and the T2 electrode (anode electrode) 12 are formed on the upper and lower surfaces of the semiconductor chip 20, respectively (FIG. 6D).

  Next, a specific configuration example in the case of using a thermistor having a negative temperature characteristic as the overheat detection unit will be described with reference to FIGS. 9 and 10.

  The semiconductor device 102 in this example is a device that controls an AC load 101 to which power is supplied from an AC power source 104, and includes a load control element 121 and an overheat protection device 122 that protects the load control element 121. . The AC load 101 is, for example, an air conditioner, an AC fan motor of an oil fan heater, an AC lamp of a copying machine, or the like.

  As shown in FIG. 10, the overheat protection device 122 includes a triac 122a that is a main element, and an overheat detection unit 122b that detects the temperature of the triac 122a. A thermistor having a negative temperature characteristic (see FIG. 8) is used for the overheat detection unit 122b. Note that the thermistor constituting the overheat detection unit 122b is fixed to the gate electrode of the triac on the triac gate electrode by using a high thermal conductive paste or solder, for example, as shown in FIG. Is provided.

  In this example, as shown in the equivalent circuit of FIG. 11 (equivalent circuit on one side of the triac), the overheat detection unit S2 (122b) is connected in series between the gate and the anode, and positive temperature characteristics are obtained. It is characterized in that it has a device having an overheat cutoff function. When the device having such a configuration is used, when the temperature of the load control element 121 becomes abnormal, the triac 122a of the overheat protection device 122 is turned on, and the overheat protection device 122 operates, whereby the fuse 103 of the electronic device 100 is operated. Is interrupted, and thermal destruction of the load control element 121 and the electronic device 100 can be prevented.

  Here, in each of the above examples, the semiconductor device in which the main element is a triac has been described. However, the present invention is not limited to this, and various semiconductors that control an AC load using a thyristor or another semiconductor element as a main element. It can be applied to the device.

  Next, a specific configuration example of the electronic device of the present invention will be described with reference to the block diagram of FIG.

  The electronic device 200 in this example includes an AC load 201 and a semiconductor device 202 that controls the AC load 201. The electronic device 200 is connected to an AC power source 204, and power is supplied from the AC power source 204 to the AC load 201. A fuse 203 is connected in series to the power supply line of the electronic device 200. The AC load 201 is, for example, an air conditioner, an AC fan motor of an oil fan heater, an AC lamp of a copying machine, or the like.

  In this example, the semiconductor device 202 is characterized in that a device having the configuration shown in FIGS. 1 to 4, that is, a solid state relay having an overheat protection function is used.

  Thus, by using the solid state relay having the overheat protection function for the electronic device 200, the electronic device 200 can be prevented from being thermally destroyed.

  The present invention can be effectively used to protect various electronic devices such as home appliances such as air conditioners and petroleum fan heaters, and OA devices such as copying machines from overheating.

It is a circuit block diagram of a solid state relay. It is a figure which shows the equivalent circuit of the one pole side of the triac which provided the overheat detection part. It is sectional drawing which shows typically an example of the triac used for this invention. It is sectional drawing which shows typically the other example of the triac used for this invention. It is a top view which shows the shape and arrangement | positioning of the T1 electrode and gate electrode of a triac. It is a figure which shows typically the preparation process of the triac of FIG. It is a graph which shows the relationship between the temperature-resistance value of the thermistor which has a positive characteristic. It is a graph which shows the temperature-resistance value relationship of the thermistor which has a negative characteristic. It is a block diagram which shows the structure of the electronic device which has an overheat protection function. It is a block diagram which shows the structure of the overheat protection apparatus (semiconductor device) used for the electronic device of FIG. It is a figure which shows the equivalent circuit of the one pole side of the triac which provided the overheat detection part. It is a block diagram which shows the structure of the electronic device using the semiconductor device which has an overheat protection function.

Explanation of symbols

S1 Overheat detector (positive temperature characteristics)
S2 Overheat detector (negative temperature characteristics)
1 Solid state relay (semiconductor device)
2 Main triac (main element)
3 Phototriac 4 Infrared light emitting diode 5 Resistance 6 Capacitor 10, 20 Semiconductor chip 20a Groove 11 T1 electrode 12 T2 electrode 13 Gate electrode 14, 24 Thermistor (overheat detection part)
DESCRIPTION OF SYMBOLS 100 Electronic device 101 AC load 102 Semiconductor device 121 Load control element 122 Overheat protection device 122a Triac 122b Overheat detection part 103 Fuse 104 AC power supply 200 Electronic device 201 AC load 202 Semiconductor device (solid state relay)
203 fuse 204 AC power supply

Claims (10)

  A semiconductor device for controlling an AC load, comprising: an overheat detection unit that detects a temperature of a main element that constitutes the semiconductor device during device operation, the overheat detection unit being an element having a positive temperature characteristic; A semiconductor device, wherein the gate signal of the main element is cut off when the temperature of the element reaches a set temperature.   2. The semiconductor device according to claim 1, wherein the overheat detecting part is fixed on the gate part of the main element with a paste or solder having high thermal conductivity.   The semiconductor device according to claim 1, wherein the overheat detection part is formed in a groove provided in a gate part of the main element.   The semiconductor device according to claim 1, wherein the overheat detection unit is a thermistor made of a conductive polymer having a positive temperature characteristic.   The semiconductor device according to claim 1, wherein the main element is a thyristor or a triac.   The semiconductor device includes a first triac having an output terminal and a gate terminal, and a second triac having an output terminal and a gate terminal, and one of the output terminals of the first triac is the second triac. 6. The semiconductor device according to claim 5, wherein the semiconductor device is a solid state relay connected to a gate terminal, and the overheat detection unit is provided in the second triac.   An electronic apparatus comprising the semiconductor device according to claim 1.   A semiconductor device for controlling an AC load, wherein an overheat detection unit including a thermistor having a negative temperature characteristic is provided at a gate portion of a main element constituting the semiconductor device. A semiconductor device having an overheat protection function for detecting a temperature of an element and controlling a gate signal of the main element.   The semiconductor device according to claim 7, wherein the main element is a thyristor or a triac. An electronic apparatus comprising the semiconductor device according to claim 8 or 9, wherein the electronic device is configured to blow a thermal fuse when the main element is overheated.

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