JPH04102031A - Temperature sensor - Google Patents

Abstract

PURPOSE:To enable accurate detection of the temperature of an object of detection by a construction wherein a pair of permanent magnets holding a temperature-sensitive member therebetween are disposed separably so that the same pole sides thereof are opposite to each other. CONSTITUTION:A temperature-sensitive member 12 is made of a magnetism compensating material and a permanent magnet 11 is fixed to the upper end of the member 12, while a conductive leaf spring 14 is fixed in the vicinity of the other end thereof. Moreover, a permanent magnet 13 is fixed to the spring 14 at a position whereat it is opposite to the magnet 11 with the member 12 held therebetween, and these magnets 11 and 13 are disposed so that the same pole sides thereof are opposed to each other. In a state wherein the temperature of the surface 21 of a semiconductor element is lower enough than the Curie temperature of the member 12, the member 12 shows ferromagnetism and the magnet 13 is attracted magnetically to the member 12. When the temperature of the surface 21 rises, on the other hand, saturation magnetization of the member 12 decreases sharply, the magnet 13 and the magnet 11 repel each other at a prescribed temperature, and the magnet 13 separates from the member 12. When the temperature of the surface 21 lowers and the repellent forces of the magnets 11 and 13 lower below the resilience of the spring 14, the magnet 13 comes into contact with the member 12. In this way, it can be known whether the member 12 exceeds a set temperature or not.

Description

[Detailed Description of the Invention] +8+ Industrial Application Field The present invention relates to a temperature sensor that detects when a temperature detection target has reached a certain temperature, and particularly relates to a small temperature sensor that detects a temperature detection target of a power semiconductor element such as a MOSFET. Regarding temperature sensors.

tb+Prior Art In general, there are conventional temperature sensors that use bimetal as a temperature sensor that detects when a temperature detection target reaches a certain temperature. In addition to appropriately selecting the composition of the metal materials that make up this bimetal, a movable contact that makes up the opening/closing contact is fixed to one side of the bimetal, and the contact is opened and closed by deformation of the bimetal due to temperature changes, and flow flows through this opening/closing contact. By detecting the presence or absence of current, it is detected whether the temperature of the object to be detected is higher than a predetermined temperature.

(C1 Problem to be solved by the invention) However, in the above conventional temperature sensor using a bimetal, the bimetal gradually deforms as the temperature of the object to be detected changes, so it is difficult to connect or open the switching contact instantaneously. There was a problem that the temperature of the temperature detection target could not be detected accurately.Also, the combinations of compositions of the metal materials that make up the bimetal are limited.
There was a problem in that the detectable temperature was limited to a relatively narrow range. As described above, a temperature sensor that can accurately detect the temperature of a detection target over a relatively wide range is strongly desired, particularly in the field of semiconductor devices.

The purpose of this invention was to focus on the fact that the saturation magnetization of a magnetic compensation material decreases rapidly as the temperature rises. By opening and closing contacts using the magnetic attraction and repulsion of permanent magnets, it is possible to set the detection temperature over a relatively wide range by selecting a magnetic compensation material, and when the set temperature is exceeded, the detection temperature can be set instantly. It is an object of the present invention to provide a small temperature sensor that can perform opening and closing operations and accurately detect temperature.

(Means for Solving Problem d1) The temperature sensor of the present invention is made of a magnetic compensation material and includes a temperature-sensitive member that comes into contact with the object of temperature detection, and a pair of permanent magnets are placed in the same position with the temperature-sensitive member sandwiched therebetween. The permanent magnets are arranged so as to be movable toward and away from each other so that their pole sides face each other, one of the permanent magnets is fixed to the temperature-sensitive member, and each permanent magnet is electrically connected to a respective one of the opening/closing contacts.

Further, a part or all of the outside of the temperature-sensing section can be constituted by a heat transfer element.

(e) Effect In this invention, W made of magnetic compensation material,
A pair of permanent magnets are arranged with the A member in between so that the same polar sides face each other, and one of the permanent magnets is fixed to the temperature-sensitive member. As shown in FIG. 1(A), when the temperature-sensitive member 3 to which one permanent magnet 1 is fixed is at a relatively low temperature, the temperature-sensitive member exhibits ferromagnetism; 1 and permanent magnet 2 are absorbed. As a result, the permanent magnet 2 is magnetically attracted to the temperature-sensitive member 3. On the other hand, as the temperature of the temperature-sensitive member 3 rises, its saturation magnetization decreases,
As shown in FIG. 2, the magnetic flux density B of the temperature-sensitive member 3 rapidly decreases until it reaches a preset temperature t. Then, the magnetic flux density B of the temperature sensitive member 3 becomes approximately 0. At this time, permanent magnet 1
The magnetic flux of the permanent magnet 2 is not absorbed by the temperature-sensitive member 3, and the permanent magnet 2 is repelled by the permanent magnet 1 and separated from the temperature-sensitive member 3, as shown in FIG. 1(B). Furthermore, when the %Q member 3 cools down from the state shown in FIG. As shown in A), it adsorbs to the temperature sensing member 3 and returns automatically.

Therefore, the permanent magnet l and the temperature-sensitive member 3 are connected to the permanent magnet 2.
The temperature state of the temperature-sensitive member 3 can be detected as an electrical signal by making the permanent magnet 18 and the permanent magnet 2 relatively movable toward and away from each other, and by providing each of the permanent magnet 18 and the permanent magnet 2 at each of the opening/closing contacts. . This signal can also be used to control the gate of a semiconductor, for example.

In addition, by configuring part or all of the temperature sensing member with a heat transfer element, the temperature sensing member comes into contact with the temperature detection target via the heat transfer element, and the temperature change of the temperature detection target is detected by the temperature detection member. conducts immediately. As a result, the permanent magnet can move toward and away from the object in accordance with changes in the temperature of the object to be detected, thereby opening and closing the opening/closing contacts.

lfl Embodiment FIG. 3 is a side view showing the configuration of a temperature sensor that is an embodiment of the present invention.

The temperature sensor 10 has an insulating member 18 on the surface 21 of the semiconductor element.
Fixed via. As this insulating member 18, a material with excellent thermal conductivity is selected. A temperature sensing member 12 bent into an L-shape is fixed to the upper surface of this insulating member I8. This temperature-sensitive member 12 is made of, for example, FeNi (30% Ni).
) and other magnetic compensation materials. A permanent magnet 11 is fixed to the upper end of this temperature sensing member 12. Further, a conductive plate spring 14 is fixed near the other end of the temperature sensing member 12 via an insulating member 17.

This leaf spring 14 has a substantially horseshoe shape, and has a movable contact 16 at the other end.
It is equipped with Furthermore, the temperature sensing member 12 in the plate blade 14
A permanent magnet 13 is fixed at a position opposite to the permanent magnet 11 with the permanent magnet 13 in between. These permanent magnets 11 and 12
are provided with their same polar sides facing each other.

The temperature sensing member 12 is provided with a fixed contact 15 that contacts the movable contact 16, and the leaf spring 14 biases the movable contact 16 toward the fixed contact 15. When the movable contact 16 contacts the fixed contact 15, the permanent magnet 13 also contacts the temperature sensing member 12.

The temperature sensor IO configured in this way is connected to the power supply circuit at the temperature sensing member IO and a part of the leaf spring 14.

As a result, the temperature sensing member 12→fixed contact 15→movable contact 1
6→A current path of the leaf spring 4 is constructed. When the temperature of the surface 21 of the semiconductor element is sufficiently lower than the Curie temperature of the temperature sensing member 12, the temperature sensing member 12 exhibits ferromagnetism, and the permanent magnet 1
3 is magnetically attracted to the temperature sensing member 12. As a result, the movable contact 16 comes into contact with the fixed contact 15, and the aforementioned current path is formed. On the other hand, when the temperature of the surface 21 of the semiconductor element increases and this is conducted to the temperature sensing member 12 via the insulating member 18,
The saturation magnetization of the temperature sensing member 12 rapidly decreases, and the temperature sensing member 12
At a predetermined temperature below the Curie temperature of , the permanent magnet 13 repels the permanent magnet 11 and separates from the temperature-sensitive member 12 . Along with this, the movable contact 16 is also separated from the fixed contact 15, and the above-mentioned current path is opened. After this, the surface 2 of the semiconductor element
When the temperature of magnet 1 decreases, the saturation magnetization of temperature-sensitive member 12 begins to increase, and the repulsive force between permanent magnet 11 and permanent magnet 13 decreases. When this repulsive force becomes less than the elastic force of the leaf spring 14, the permanent magnet 13 comes into contact with the temperature sensing member 12. When the temperature of the surface 21 of the semiconductor element further decreases, the saturation magnetization of the temperature-sensitive member 12 increases sufficiently, and the magnetic flux of the permanent magnets 11 and 13 is absorbed by the temperature-sensitive member 12. Adsorb. When the permanent magnet 13 contacts the temperature-sensitive member 12, the movable contact 16 contacts the fixed contact 15, and the opening/closing contact is opened. Therefore, the opening/closing contact is the surface 21 of the semiconductor element.
Automatically resets when the temperature drops.

By detecting the current flowing through the temperature sensor 10 as described above, it is possible to know whether the temperature sensing member 12 has exceeded the set temperature, that is, whether the surface 21 of the semiconductor element, which is the temperature detection target, has exceeded the set temperature. be able to.

FIGS. 4A and 4B are a side view and a bottom view, respectively, of a temperature sensor according to another embodiment of the present invention.

Temperature sensor 31 is attached to surface 21 of the semiconductor element via insulating member 40 . The temperature decay sensor 31 has a cylindrical heat transfer element 37, and a temperature sensing member 33 is fixed near the upper end of the heat transfer element 37. This temperature sensing member 33 protrudes from the side surface of the heat transfer element 37, and a permanent magnet 32 is fixed to this protrusion. Further, one end of a plate bar 235 is fixed to the permanent magnet 32 via an insulating member 36.

A permanent magnet 34 and a movable contact 38 are fixed near the other end of the plate 235. The movable contact 38 is the temperature sensing member 3
The permanent magnet 34 is attached to and detached from a fixed contact 39 fixed to a protruding portion of the magnet 3, and the permanent magnet 34 is installed with the temperature sensing member 33 in between and the permanent magnet 32 and the same polarity sides facing each other.

Further, the plate spring 35 urges the movable contact 38 toward the fixed contact 39 side.

With the above configuration, the temperature of the surface 21 of the semiconductor element is transmitted to the temperature sensing member 33 via the heat transfer element 37, and the temperature of the surface 21 of the semiconductor element is transferred to the temperature sensing member 33 through the heat transfer element 37. The movable contact 39 can be brought into contact with and separated from the fixed contact 39 by the temperature change. As this heat transfer element, a known double pipe having a heat receiving part on the lower side and a heat dissipating part on the E side can be used. By using a heat pipe as the heat transfer element 37 in this way, since the temperature difference between the heat receiving part and the heat radiation part is small, it is possible to sufficiently sense the temperature of the surface 21 of the semiconductor element, which is the object of temperature detection, although it is delayed. The heat can be conducted to the heating member 33, and a change in temperature of the object to be detected can be detected. Further, by using a cylindrical heat pipe, the installation area for the temperature detection target can be reduced, and the requirements for providing a temperature sensor in a semiconductor element can be satisfied. In this case, if the overall height of the temperature sensor is also restricted, the overall height of the temperature sensor 31 can be lowered to satisfy the requirement by bending the heat transfer element 37, as shown in FIG. be able to.

Note that a temperature-sensitive ferrite or an amorphous material can be used as the magnetic compensation material that is the material of the temperature-sensitive member. Further, the heat transfer element is not limited to a heat pipe.

(Effects of the Phantom Invention According to this invention, the switching contacts can be instantaneously opened and closed by using the repulsive force generated between a pair of permanent magnets due to changes in the magnetic properties of the temperature-sensitive member due to temperature rise, and the temperature can be detected. It has the advantage of being able to accurately detect temperature changes in a relatively wide temperature range.Also, it is possible to directly open and close the gate circuit of the power MO3FET using the above-mentioned switching contacts, making it possible to reduce the size of the gate switching circuit. This is advantageous when considering temperature sensing functions.

[Brief explanation of the drawing]

FIGS. 1A and 1B are schematic configuration diagrams explaining the present invention in detail, and FIG. 2 is a diagram showing changes in characteristics of the temperature sensing member in the same temperature sensor with respect to temperature. Further, FIG. 3 is a side view showing the configuration of a temperature sensor according to an embodiment of the present invention, and FIGS. 4(A) and (B) are a side view and a bottom view, respectively, of a temperature sensor according to another embodiment of the present invention. Figure, 5th
The figure is a side view of a temperature sensor according to yet another embodiment of the invention. 2.11, 13.32.34-Permanent magnet, 12.33-
Temperature-sensitive member 1. 39 - Fixed contact, 16. 38 - Movable contact, - Heat transfer element, Surface of semiconductor element (temperature detection target).

Claims (2)

[Claims] (1) A temperature-sensitive member made of magnetic compensation material and in contact with the temperature detection target is provided, and a pair of permanent magnets are arranged with the temperature-sensitive member in between so that the same polar sides face each other so that they can move toward and away from each other, A temperature sensor characterized in that one of the permanent magnets is fixed to the temperature sensing member, and each permanent magnet is electrically connected to a respective contact of the opening/closing contact. (2) The temperature sensor according to claim (1), wherein a part or all of the outside of the temperature sensing section is constituted by a heat transfer element.