JP2519304B2 - Semiconductor device and its circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a temperature measuring terminal, and more particularly to a terminal capable of accurately measuring the temperature of a region in which a main current flows. The present invention relates to a semiconductor device and a semiconductor circuit having the.

[Prior Art] A semiconductor device, in particular, a semiconductor device through which a large current of 1 A or more flows, has a problem in that the semiconductor device itself is destroyed when the heat generated by the jule heat during conduction becomes excessive. As a conventional technique for solving such a problem, an element for detecting a temperature is provided on an IC or the like which constitutes a circuit, and this element detects that the temperature of a semiconductor device rises above a certain level. In this case, there is known a technique of limiting the current of a semiconductor device which allows a large current to flow.

FIG. 8 is a circuit diagram showing the structure of a semiconductor circuit according to this type of conventional technique. In FIG. 8, 100 is a semiconductor device, 1
01 is a diode for temperature measurement, 102 is a differential amplifier, 103 is
It is an AND circuit.

The prior art shown in FIG. 8 detects the temperature of a semiconductor device through which a large current flows and shuts off the current of the semiconductor device based on the temperature detection signal.

In this conventional technique, when the semiconductor device 100 operates in a steady state, the differential amplifier 102 gives a High signal to the terminal S of the AND circuit 103. As a result, the semiconductor device 10
For 0, a signal having the same level as the gate signal applied to the terminal G of the AND circuit 103 is input to the gate, and the operation is controlled.

The semiconductor device 100, when performing the above operation,
The on-resistance and the current generate heat. The heat is transmitted to the diode 101, and a constant current flows through the diode 101.
Reduce the voltage across. Now, if the heat generation of the semiconductor device 100 becomes excessive for some reason, the diode 101
The voltage drop across both ends of the
Changes its output from High to Low in relation to the resistor Rref that is generating the voltage for reference.

In this case, even if a High signal is input to the terminal G as the gate signal, the signal input to the semiconductor device 100 is set to Low by the AND circuit 103.
Will be cut off from its current and will be protected from thermal destruction.

As this type of conventional technique, for example, Shinny. Two people outside of Sea, "Anyu Chip and Anyu Pack Cage for Higher Power", IEE Transaction on Consumer Electronics, Vol. See 26, page 54 ~
Page 72, February 1980 (2 people outside CINI.C, "A New Chip an
d A New Package for Higher Power ”IEEE Transaction
on Consumer Eelectronics, Vol.CE-26, pp54-72,1980Fe
The technologies described in b) etc. are known.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technique, the temperature of the semiconductor device itself is not increased due to the large distance between the semiconductor device that flows a large current and the element that detects the temperature. It is difficult to detect, and it takes time for heat to be transmitted to the temperature detection element, which causes a problem in that there is a time delay in temperature detection. It has been difficult to prevent thermal destruction of the semiconductor device.

It is an object of the present invention to provide a semiconductor device and a semiconductor circuit that solve the above-mentioned problems of the prior art and can instantly detect the temperature of the semiconductor device itself.

[Means for Solving the Problems] According to the present invention, the object is to reduce the temperature of a semiconductor device,
This is achieved by detecting based on the characteristics of the semiconductor device. That is, the above-mentioned object is to provide another temperature measuring terminal in addition to the output terminal through which the main current flows in the semiconductor device in which the voltage drops due to the diffusion potential of the junction when conducting, and connect the load in series to this terminal. It is achieved by measuring the voltage drop of the semiconductor device using the terminal to which the load is connected.

[Operation] The voltage drop due to the diffusion potential of the junction of the semiconductor device changes depending on the temperature of the junction. Therefore, by measuring this voltage drop, the temperature of the semiconductor device itself can be detected, the detection accuracy is improved, and the detection time delay is eliminated.

Embodiments Embodiments of a semiconductor device and a semiconductor circuit according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a semiconductor device according to a first embodiment of the present invention, FIG. 2 is a diagram for explaining current-voltage characteristics when the semiconductor device is conducting, and FIG. It is a figure explaining the relationship with a measurement voltage. In FIG. 1, 1 is a semiconductor device, 10 is an n layer, 11 is a p layer, 21 is a cathode electrode,
22 is the first anode electrode, 23 is the second anode electrode, 50
Is a load resistance and 110 is a pn junction.

The first embodiment of the present invention shown in FIG. 1 has an n layer 10 and a p layer.
The present invention is applied to a pn junction diode according to 11 in which a cathode electrode is formed on the n layer 10 and a first anode electrode 22 and a second anode electrode 23 are formed on the p layer 11. . The load resistance R50 is connected to the second anode electrode 23, and is further short-circuited to the first anode electrode 22.

In the semiconductor device 1 which is the pn junction diode, a voltage drop occurs due to the diffusion potential of the pn junction 110 when the semiconductor device 1 is conductive.
This voltage drop shows a current-voltage characteristic as shown in FIG. When the load resistance to the diode is small and a large amount of current flows, the voltage drop depends on the magnitude of the current, but the voltage drop when the load resistance is large and the current is small, that is, the voltage at the output current rising portion. The drop V _T is pn
The voltage drop is due to the diffusion potential of the junction 110. The voltage drop due to this diffusion potential is generally pn
It changes depending on the temperature of the junction 110. In the present invention, the temperature of the pn junction 110 is detected by detecting the voltage drop due to the diffusion potential. Therefore, in the embodiment shown in FIG. 1, the value of the load resistance R50 connected to the second anode electrode 23 is larger than that of the second anode electrode 23 compared to the current density flowing to the first anode electrode 22. It is selected so that the density of the current flowing in is less than 1/10.

The voltage drop due to the diffusion potential of the pn junction 110 is the first
In the embodiment shown in the figure, the input voltage V _1-
When a voltage of V ₀ is applied, it can be obtained by measuring the voltage of V ₂ -V ₀ . The voltage drop due to this diffusion potential has a temperature characteristic as shown in FIG. 3, and changes according to the temperature of the pn junction of the semiconductor device 1. That is, now
The current flowing through the anode electrode 23 is limited to a constant value by the resistor R50, and the voltage drop due to the diffusion potential measured at that time is set.
When V ₂ -V ₀ is measured, the voltage is 0.7 V at room temperature of 25 ° C. and 0.4 V at the semiconductor device 1 temperature of 150 ° C., for example. By detecting this voltage through the amplifier circuit,
A change in the detected voltage of V ₂ -V ₀ of about 5 mV can be detected, and the embodiment shown in FIG.
It is possible to detect the temperature change of 1 with high accuracy with an error of about 2 ° C.

As described above, according to the first embodiment of the present invention shown in FIG. 1, the output terminal of the semiconductor device 1 is divided, a load is connected to one of them, and the voltage drop due to the diffusion potential of the pn junction is measured. By doing so, the temperature of the semiconductor device 1 itself can be measured in the immediate vicinity of the flow of the main current, so that the accuracy of temperature detection can be improved and the time lag of temperature detection can be reduced. Further, according to this embodiment, even when the semiconductor device 1 locally generates heat, the voltage drop at that portion can be detected as V ₂ -V ₀ , so that such local heat generation is possible. Can also be detected.

FIG. 4 is a sectional view showing the structure of a semiconductor device according to the second embodiment of the present invention, and FIG. 5 is a view showing its equivalent circuit. In FIG. 4, 12 is a p ⁺ layer, 13 is an n ⁻ layer, 14 is a p layer, and 15 is an n ⁺ layer.
A layer, 24 is a first emitter electrode, 25 is a second emitter electrode, 30 is an insulated gate, and other reference numerals are the same as those in FIG.

The second embodiment of the present invention shown in FIG.
(Insulated Gate Bipolar Transistor). The semiconductor device 1 as an IGBT has a p ⁺ layer 12 and an n ⁻ layer 1
3, p layer 14, n ⁺ layer 15 and insulated gate 30 (G) are provided,
A collector electrode 26 is formed on the p ⁺ layer 12, and an n ⁺ layer 15 is formed on the other main surface opposite to the main surface on which the collector electrode 26 is formed.
The first emitter electrode 24 (E ₂ ) and the second emitter electrode 25 (E ₁ ) that short-circuit the p-type layer 14 and the p-layer 14 are formed. A negative resistance R50 is connected to the second emitter electrode 25.

Also in the second embodiment of the present invention shown in FIG. 4,
The temperature of the semiconductor device 1 can be detected in the same manner as described with reference to FIG. That is, FIG. 4, in Figure 5, the voltage V _G is applied to the insulated gate G30, the IGBT as a semiconductor device 1 as a conducting state, by measuring the voltage V ₂ -V _0, p ⁺ layer 12 It is possible to measure the voltage drop due to the diffusion potential of the pn junction 110 composed of the n ^- layer 13 and the n ^- layer 13. Also in this embodiment, as in the case of the pn diode shown in FIG. 1, the temperature of the semiconductor device 1 can be directly detected by measuring the diffusion potential of the pn junction described above.

It is desirable to devise the measuring circuit so that the above-described V ₂ -V ₀ voltage measurement is performed only when the control signal voltage V _G is applied to the gate G. This is necessary in order to prevent a decrease in detection accuracy due to a high voltage V ₁ -V ₀ when the semiconductor device 1 is off.

FIG. 6 is an equivalent circuit diagram showing the configuration of the third embodiment of the present invention.

The semiconductor device in the embodiment of FIG. 6 is the same IGBT as that described with reference to FIG.
A series circuit of two resistors RB and RA having large and small resistance values and a switching element SW2, SW1 having gates G2, G1 is connected to E ₁ .

In the embodiment shown in FIG. 6, the control voltage V _G is applied to the gate G of the IGBT to keep the IGBT conductive, a signal is applied only to the gate G2 of the switching element SW2, and only the switching element SW2 is turned on to set V The temperature of the IGBT can be detected by measuring the voltage of _2- V ₀ , which is exactly the same as the case described with reference to FIGS. 4 and 5.

The embodiment shown in FIG. 6 further enables detection of the current flowing through the IGBT itself. In this case, leave the IGBT in the conductive state as described above and switch the switching element SW.
By applying a signal only to the gate G1 of 1 and turning on only the switching element SW1 to measure the voltage of V ₂ -V ₀ , the current flowing through the second emitter E ₁ is detected. It is possible to know the current flowing through Emitter E ₂ .

That is, in this case, the value of the resistor RA is connected between the switch element SW1 and the second emitter E ₁ is such that the current density of the second emitter E ₁ and a first emitter E ₂ is substantially identical It is set to a small value, usually several tens of Ω to several hundred Ω. Thus, a first current flowing through the emitter E ₂ of the semiconductor device, a current detected flowing through the second emitter E _1, the first and second emitter E _2, the conduction area ratio of E ₁ Can be asked for.

On the other hand, in order to detect the temperature, the switching element 2 and the second
The value of the resistor RB connected to the emitter E _{1 of} is for measuring the voltage drop at the low output where the output current rises, as explained with reference to FIG. It is set to a relatively large value of several kΩ to several hundred kΩ. This value is
The same applies to the embodiment shown in FIGS. 4 and 5.

As described above, in the third embodiment of the present invention shown in FIG. 6, two loads having different resistance values are connected to one second emitter E ₁ , and these are controlled by a switching element. Thus, the temperature and current of the semiconductor device can be detected using one measuring terminal.

FIG. 7 is a circuit diagram showing a fourth embodiment of the present invention,
The reference numerals in the figure are the same as those in FIG.

The embodiment shown in FIG. 7 is an application example of the present invention in which the temperature of the semiconductor device 100 is detected to be above a certain temperature and the gate of the semiconductor device is controlled based on the detection result to suppress heat generation. It is shown.

In FIG. 7, the semiconductor device 100 is normally set to High.
The output of the differential amplifier 102 outputting the level signal is controlled via the AND circuit 103 by the gate signal applied to the terminal G of the AND circuit 103 applied to the terminal S.
The temperature of the semiconductor device 100 is detected by the differential amplifier 102 in which the voltage of the resistor R50 connected to the second emitter E ₁ of the semiconductor device 100 is given via the resistor Rref. That is, the differential amplifier 102 changes its output signal from High to Lo when the temperature of the semiconductor device 100 becomes a predetermined value or higher, that is, when the output voltage of the resistor R50 becomes a predetermined value or lower.
The gate voltage applied to the semiconductor device 100 is changed to w to operate in the OFF state. As a result,
The circuit shown in the figure can prevent excessive heat generation of the semiconductor device 100, and can prevent the semiconductor device 100 from being thermally damaged.

In the above-described embodiment, when it is determined that the heat generation of the semiconductor device 100 is excessive, the gate voltage of the semiconductor device 100 is turned off to protect the semiconductor device 100, but the present invention reduces the gate voltage, and Modifications that reduce the current flowing through the device are also possible.

The above-described embodiment of the present invention is one in which the present invention is applied to a semiconductor device having a pn junction. However, the present invention is not limited to a semiconductor device having a Schottky junction. It can also be applied to a semiconductor device.

As described above, according to the present invention, since the temperature of the semiconductor device itself can be detected, it is possible to control the output current of the semiconductor device with high accuracy and without time delay, and It is possible to prevent the semiconductor device from being damaged by the above.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a semiconductor device according to a first embodiment of the present invention, FIG. 2 is a diagram for explaining current-voltage characteristics when the semiconductor device is conducting, and FIG. FIG. 4 is a diagram showing the relationship with the measurement voltage (voltage drop due to the diffusion potential of the pn junction), FIG. 4 is a sectional view showing the configuration of the semiconductor device of the second embodiment of the present invention, and FIG. 5 is its equivalent circuit. FIG. 6 is an equivalent circuit diagram showing the configuration of the third embodiment of the present invention, and FIG.
FIG. 8 is a circuit diagram showing a fourth embodiment of the present invention, and FIG. 8 is a circuit diagram showing an example of a conventional semiconductor circuit. 1,100 ... Semiconductor device, 10 ... n layer, 11,14 ... p layer, 12
...... p ⁺ layer, 13 ...... n ^- layer 15 ...... n ⁺ layer, 21 ...... cathode electrode, 22 ...... first anode electrode, 23 ...... second anode electrode, 24 ...... first Emitter electrode, 25 …… Second emitter electrode, 26 …… Collector electrode, 30 …… Insulation resistance, 50 ……
Load resistance, 101 ... Diode, 102 ... Differential amplifier, 10
3 …… AND circuit, 110 …… pn junction.

Front page continuation (72) Inventor Yasuda Yasuda 4026, Kuji-machi, Hitachi, Hitachi, Ibaraki 4026 Hitachi Research Laboratory, Hitachi, Ltd. (72) Inki Aki 4026, Kuji-cho, Hitachi, Ibaraki Hitachi, Ltd. 56) References JP-A-62-143450 (JP, A) JP-A-62-65517 (JP, A) JP-A-55-117267 (JP, A) JP-A-62-124764 (JP, A)

Claims (7)

(57) [Claims] 1. In a semiconductor device in which a voltage drop occurs due to a diffusion potential of a junction when conducting, two electrodes of a main electrode and a detection electrode are separated on one side of an electrode of the semiconductor device through which a conducting current flows. The semiconductor device has a common junction through which the main current and the detection current from the main electrode and the detection electrode flow, and the detection electrode is connected to the main electrode via a load. The semiconductor device is characterized in that the voltage drop between the detection electrode and the electrode on the other side of the electrode through which the conduction current flows is measured to measure the voltage drop due to the diffusion potential of the junction. 2. The semiconductor device according to claim 1, wherein the junction of the semiconductor device is a pn junction or a Schottky junction. 3. The semiconductor device according to claim 1, wherein the semiconductor device is a pn junction diode, a Schottky diode, or a semiconductor device in which a fractional carrier is injected. 4. The semiconductor device according to claim 1, wherein a current density in a region where the detection current flows is set to be smaller than a current density in a region where the main current flows. 5. The semiconductor device according to claim 4, wherein the current density of the region where the detection current flows is 1/10 or less of the current density of the region where the main current flows. 6. In a semiconductor device in which a voltage drop occurs due to a diffusion potential of a junction when conducting, two electrodes, a main electrode and a detection electrode, are separately provided on one side of an electrode for flowing a conducting current of the semiconductor device. The semiconductor device has a common junction in which a main current and a detection current from the main electrode and the detection electrode flow, and the detection electrode switches between two loads having different resistance values and these loads. The junction is connected to the main electrode via a switching element, the two loads are switched, and the voltage drop between the detection electrode and the electrode on the other side of the electrode through which the conduction current flows is measured to measure the junction. A semiconductor device characterized by measuring a voltage drop due to the diffusion potential of the semiconductor device and a main current of the semiconductor device. 7. A semiconductor device according to any one of claims 1 to 6 and a voltage drop measuring means, wherein the measured voltage drop is less than or equal to a preset voltage. In the case of a semiconductor circuit, the semiconductor circuit is characterized in that the current of the semiconductor device in a conductive state is limited or cut off.