JPH0267767A - Semiconductor device and its circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semiconductor device having a terminal for measuring temperature, and in particular, to a terminal that makes it possible to accurately measure the temperature in a region where a main current flows. The present invention relates to a semiconductor device and a semiconductor circuit.

[Prior Art] Semiconductor devices, especially semiconductor devices that flow a large current of IA or more, have a problem in that the semiconductor device itself is destroyed if the amount of heat generated by Joule heat during conduction becomes excessive. As a conventional technique to solve such problems, a temperature detecting element is provided on the circuit or in an IC, etc. constituting the circuit, and this element detects when the temperature of the semiconductor device rises above the -chamber. In such a case, there is a known technique for limiting the current of a semiconductor device through which a large current flows.

FIG. 8 is a circuit diagram showing the configuration of a semiconductor circuit according to this kind of conventional technology. In FIG. 8, 100 is a semiconductor device;
101 is a diode for temperature measurement, 102 is a differential amplifier, and 103 is an AND circuit.

The conventional technique shown in FIG. 8 detects the temperature of a semiconductor device through which a large current flows, and cuts off the current of the semiconductor device based on a temperature detection signal.

In this prior art, when the semiconductor device 100 is operating in a steady state, the differential amplifier 102 is connected to the AND circuit 1
A high signal is given to the terminal S of 03. As a result,
The operation of the semiconductor device 100 is controlled by a signal having the same level as the gate signal applied to the terminal G of the AND circuit 103 being input to its gate.

When the semiconductor device 100 performs the above-described operation,
Heat is generated due to the on-resistance and current.

The heat is transferred to the diode 101 and lowers the voltage across the diode 101 through which a constant current flows. Now, if the heat generation of the semiconductor device 10o becomes excessive for some reason, the voltage drop across the diode 101 becomes less than a predetermined value, and the differential amplifier 101, in relation to the resistor Rref that generates the reference voltage, Its output is H
i g Change from h to Low.

In this case, even if a High signal is input to the terminal G as a gate signal, the AND circuit 103

Since the signal input to the semiconductor device 100 is set to Low, the current to the semiconductor device 1100 is cut off, and the semiconductor device 1100 is protected from thermal destruction.

Examples of this type of prior art include, for example, "A New Chip and a New Package for Buyer Power" by Shussy et al., and IE Transactions on Consumer Electronics.

Pol, C.E.26. Pages 54 to 72.

February 1980 (CINl, 2 famous authors other than C, rANe
w Chip and A New Package
for HigherPower
Transaction on Consume
rE electronics, Vol, CE-26,
A technique described in, for example, pp. 54-72 (Feb. 1980) is known.

[Problems to be Solved by the Invention] However, in the conventional technology, the distance between the semiconductor device through which a large current flows and the element that detects temperature is large, and the temperature of the semiconductor device itself is detected due to the existence of thermal resistance between them. In addition, since it takes time for heat to be transmitted to the temperature detection element, there is a problem that there is a time delay in temperature detection. It was difficult to prevent thermal destruction of the

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to provide a semiconductor device and a semiconductor circuit that make it possible to instantly detect the temperature of the semiconductor device itself.

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

[Operations] The voltage drop due to the diffusion potential of a junction in a 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 there is no time delay in detection.

[Embodiments] Hereinafter, embodiments of a semiconductor device and a semiconductor circuit according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing the configuration of a semiconductor device according to a first embodiment of the present invention, FIG. 2 is a diagram illustrating current-voltage characteristics when the semiconductor device is conductive, and FIG. 3 is a diagram showing temperature and voltage characteristics of the semiconductor device. 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-type, 21 is a cathode electrode, 22 is a first anode electrode, and 23 is a second 7-node electrode.

50 is a load resistor, and 110 is a pn junction.

A first embodiment of the invention, shown in FIG.
The present invention is applied to a pn junction diode made of
includes a first anode electrode 22 and a second anode electrode 23
is formed and configured. A load resistor R50 is connected to the second anode electrode 23, and is further short-circuited to the first anode electrode 22.

The semiconductor device 1, which is a pn junction diode, causes a voltage drop due to the diffusion potential of the pn junction 110 when it is conductive. This voltage drop exhibits current-voltage characteristics as shown in FIG. If the load resistance to the diode is small and a large current flows, the voltage drop will depend on the magnitude of the current, but if the load resistance is large and the current is small, the voltage drop will be the voltage at the rising edge of the output current. The drop 7 is a voltage drop due to the diffusion potential of the pn junction 110. The voltage drop due to this diffusion potential generally changes depending on the temperature of the pn junction 110, as described later. The present invention attempts to detect the temperature of the pn junction 110 by detecting the voltage drop due to this diffusion potential.

Therefore, in the embodiment shown in FIG. It is selected so that the flowing current density is 1/1o or less.

The voltage drop due to the diffusion potential of the pn junction 110 described above is caused by the input voltage V
, -V. When a voltage of 2-vo is applied, it can be obtained by measuring the voltage of 2-vo. The voltage drop due to this diffusion potential has temperature characteristics as shown in Figure 3.
It changes according to the temperature of the ρn junction of the semiconductor device 1. That is, the current flowing through the anode electrode 23 is now connected to the resistor R5.
When the voltage drop V, -V, due to the diffusion potential measured at that time is limited to a constant value of 0, the voltage is, for example, 0.7 V at a room temperature of 25°C, and the semiconductor device 1
When the temperature is 150°C, it becomes 0.4V. By detecting this voltage through an amplifier circuit.

It is possible to detect changes in the detection voltages of V and -Vo of about 5 mV, and the embodiment shown in FIG. is possible.

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 very close to where the main current flows, so the accuracy of temperature detection can be improved and the time lag in temperature detection can be reduced. Furthermore, according to this embodiment, even if the semiconductor device 1 generates heat locally, the voltage drop at that part can be detected as V2 - V, so such local heat generation can be detected. can also be detected.

FIG. 4 is a sectional view showing the structure of a semiconductor device according to a second embodiment of the present invention, and FIG. 5 is a diagram showing its equivalent circuit. Fourth
In the figure, 12 is a p+ layer, 13 is an n- layer, and 14 is a pF layer.
Il, 15 is an n layer, 24 is a first emitter electrode, 25
3 is a second emitter electrode, 30 is an insulated gate, and other symbols are the same as in FIG. 1.

A second embodiment of the invention, shown in FIG.
B T (In5lated Gate Bip
This is applied to the optical trans-sister. The semiconductor device 1 as an IGBT has a p+ calendar 12.
n-calendar 13. p layer 14. n+ layer 15 and insulated gate 30
(G) and p+! 12 has a collector electrode 26
However, on the other main surface opposite to the main surface on which the collector electrode 26 is formed, a first emitter electrode 24 (E,) that short-circuits the n+ layer 15 and the pJ layer 14 and a second emitter electrode 24 are formed. An electrode 25 (E type) is formed and configured. The second emitter electrode 25 has a negative resistance R50.
is connected.

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, in FIGS. 4 and 5, voltage Va is applied to the insulated gate G30, and the semiconductor device 1
The voltage drop due to the diffusion potential of the pn junction 110 consisting of the p+ layer 12 and the n- layer 13 can be measured by measuring the voltage V2-V with the IGBT as conductive. In this embodiment as well, as in the case of the pn diode shown in FIG. 1, it is possible to directly detect the temperature of the semiconductor device 1 by measuring the diffusion potential of the pn junction described above.

It is desirable to devise a measuring circuit so that the above-mentioned voltage measurement of V2-Vo is performed only when the control signal voltage 6 is applied to the gate G. This is the semiconductor device 1
This is necessary in order to prevent the detection accuracy from decreasing due to the voltage of voVo becoming high when the voltage is off.

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

The semiconductor device in the embodiment of FIG. 6 is an IGBT similar to that explained in FIG. 4, and the second emitter electrode E1 has two resistors RB and RA having different resistance values.
and gate G2. Switching element SW having Gl
2. A series circuit of SWI is connected.

In the embodiment shown in FIG. 6, a control voltage va is applied to the gate G of the IGBT to keep the IGBT in a conductive state, and a signal is applied only to the gate G2 of the switching element SW2.
When only switching element SW2 is turned on, V2-Vo
The fact that the temperature of the IGET can be detected by measuring the voltage is exactly the same as in the case explained with reference to FIGS. 4 and 5.

The embodiment shown in FIG. 6 further allows the current flowing through the IGBT itself to be detected.

In this case, the IGBT is kept conductive as described above, a signal is applied only to the gate G1 of the switching element SWI, only the switching element SWI is turned on, and V2-
By measuring the voltage of V, the current flowing through the second emitter E can be detected, and the current flowing through the first emitter E2 can be determined from this detected value.

That is, in this case, the value of the resistor RA connected between the switch element SWI and the second emitter E□ is set to a small value such that the current densities of the second emitter E1 and the first emitter E2 are almost the same. Value, usually several 10 Ω to several 100 Ω
is set to the value of As a result, the current flowing through the first emitter E2 of the semiconductor device is combined with the detected current flowing through the second emitter E2 and the first and second emitters E2. E
It can be determined by the conduction area ratio of .

On the other hand, the value of the resistor RB connected between the switching element 2 and the second emitter E for temperature detection is
As explained with the figure, since the purpose is to measure the voltage drop at low output where the output current rises, it is set to a relatively large value, from several ohms to several hundred ohms. This value is the same for the embodiments of FIGS. 4 and 5.

As mentioned 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□, and these are controlled by a switching element. Accordingly, the temperature and current of the semiconductor device can be detected using one measurement terminal.

FIG. 7 is a circuit diagram showing a fourth embodiment of the present invention, and the reference numerals in the figure are the same as those in FIG. 8.

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 level, and the gate of the semiconductor device is controlled based on the detection result to suppress heat generation. It shows.

In FIG. 7, the semiconductor device 100 is in Hi state during normal operation.
The output of the differential amplifier 102 outputting the g h level signal is controlled via the AND circuit 103 by the gate signal applied to the terminal G of the AND circuit 103, which is applied to the terminal S.

The temperature of the semiconductor device 100 is detected by the differential amplifier 102 to which the voltage of a resistor R50 connected to the second emitter E1 of the semiconductor device 100 is applied via a resistor Rref. That is, the differential amplifier 102 changes its output signal from High to Low when the temperature of the semiconductor device 100 exceeds a predetermined value, that is, when the output voltage of the resistor R50 becomes below a predetermined value. , operates to turn off the voltage applied to the semiconductor device 100. As a result, the circuit shown in FIG. 7 can prevent excessive heat generation in the semiconductor device 100, and can prevent the semiconductor devices il and OO from being thermally destroyed.

In the above 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.
Although the semiconductor device 100 is protected as F, the present invention can also be modified to reduce the gate voltage and the current flowing through the semiconductor device.

The embodiment of the present invention described above applies the present invention to a semiconductor device having a pn junction, but the present invention is applicable to any semiconductor device that causes a voltage drop due to the diffusion potential of the junction, such as a semiconductor device having a Schottky junction. It can also be applied to devices.

[Effects of the Invention] As explained above, according to the present invention, the temperature of the semiconductor device itself can be detected, so the output current of the semiconductor device can be controlled with high precision and without time delay, and the temperature It is possible to prevent damage to the semiconductor device due to

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the configuration of a semiconductor device according to a first embodiment of the present invention, FIG. 2 is a diagram illustrating current-voltage characteristics when the semiconductor device is conductive, and FIG. 3 is a diagram showing temperature and voltage characteristics of the semiconductor device. FIG. 4 is a cross-sectional view showing the structure of a semiconductor device according to a second embodiment of the present invention. FIG. 5 is a diagram showing the equivalent circuit, and FIG. 6 is a diagram showing the third embodiment of the present invention.
FIG. 7 is a circuit diagram showing a fourth embodiment of the present invention, and FIG. 8 is a circuit diagram showing an example of a semiconductor circuit according to the prior art. 1.100... Semiconductor device, 10...
0 layer, 11.14...p calendar, 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, 10
1...Diode, 102...Differential amplifier, 103...AND circuit, 110...PN junction. Figure 1 T V X IX Figure Figure Figure Figure

Claims (1)

[Claims] 1. In a semiconductor device that causes a voltage drop due to the diffusion potential of a junction when conducting, at least two output terminals provided on the semiconductor device and a semiconductor device connected in series to one of the output terminals. 1. A semiconductor device comprising: a load; the voltage drop of the semiconductor device can be measured using an output terminal connected to the load; 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 or 2, wherein the semiconductor device is a pn junction diode, a Schottky diode, or a semiconductor device in which minority carrier injection occurs. 4. A semiconductor device in which a voltage drop occurs due to the diffusion potential of a junction when conductive, comprising a first region through which most of the current flows during conduction, and a second region through which a portion of the current flows; A semiconductor device characterized in that a current density in the region is set to be lower than a current density in the first region, and a voltage drop when the second region is conductive can be measured. 5. A semiconductor device comprising the semiconductor device according to one of claims 1 to 4 and a voltage drop measuring means, and when the measured voltage drop is equal to or lower than a preset voltage, A semiconductor circuit characterized by limiting or cutting off the current of a semiconductor device in a conductive state.