FR2841686A1 - Installation for detecting an event of excessive temperature of an electronic component, method for detecting such event, and monolithic component equipped with installation - Google Patents

Abstract

The installation for a posterior detection of an event of excessive temperature in the course of functioning of an electronic component comprises a temperature element in the form of a diode (D) measuring the temperature and providing a temperature signal (IB), an amplifier stage in the form of a bipolar transistor (T) receiving the temperature signal and delivering an output signal (IC), a registering facility in the form of a fuse (F) receiving the output signal (IC) and, if the measured temperature is higher than a temperature limit, registering a perturbation signal in an irreversible manner. The registering facility (F) possesses a fundamental state and a perturbed state, and in the fundamental state it has a destructible conducting path preferentially of metal or polycrystalline silicon which is destroyed in the case of perturbation, or it comprises a Zener diode, or an insulator preferentially of metal oxide which passes to a conducting state. The amplifier stage comprises a bipolar transistor (T) of type n-p-n whose base circuit comprises the temperature element (D) and whose collector circuit comprises the registering facility (F), or the bipolar transistor (T) is of type n-p-n and the registering facility (F) is branched between the collector and the ground in parallel with the diode, or an output terminal (A) is connected to the collector of bipolar transistor (T) of type n-p-n and a resistor (R) is connected between the collector and the ground. The temperature element is a semiconductor element such as a diode (D) connected in reverse, or a diode branched in direct whose resistance depends on temperature. A monolithic component (claimed) comprises at least one installation (claimed) for detecting an excessive temperature, and at least one other circuit. The installation and at least one other circuit are integrated in a monolithic fashion. The monolithic component comprises three installations with different temperature limits, where the first installation is activated for the measurement of functioning, the second installation is activated independently of the first installation, and the third installation is activated for the final measurement. The third temperature limit is higher than the second temperature limit, and the second and the third installations are activated in common. A method (claimed) for detecting an event of excessive temperature includes the activation of the first installation and, in the case of temperature exceeding the first temperature limit, the registering of the first perturbation signal; and at the end of functioning state verifying at a temperature below the first temperature limit if the perturbation signal is registered in the first facility.

Description

Field of the Invention The present invention relates to an installation for

  detection for an electronic component, and a monolithic component

  having at least one detection installation.

  The invention also relates to a detection method

  of an excessive temperature event of such a component.

  STATE OF THE ART Electronic components can be destroyed by exceeding a maximum authorized operating temperature or 10 limit temperature. Even a brief overshoot of the limit temperature can deteriorate the reliability of a component so that the component deviates from the specific parameters authorized for operation. The cause of the failure may, if necessary, not be related to the previous exceeding of the limit temperature. He will not

  no longer possible to determine the cause and time of this failure later.

  To avoid exceeding the limit temperature, detection systems are known which make it possible to measure an operating temperature and compare it with the limit temperature. If the limit temperature is exceeded, the heat sources in the component are cut off in order to generally prevent the temperature rise from continuing. Once the component has cooled to a temperature below the limit temperature, you can activate the

heat source.

  Such detection installations generally have a pn junction, for example a diode, the exponentially dependent blocking current of which is used as the base current applied to a transistor. The transistor generates a voltage drop on its collector resistor which gives an output signal which can be used to cut off the heat source by the temperature-dependent output signal.

  However, in such a detection installation, it cannot be checked a posteriori if there has been a temperature overshoot and if the limit temperature has been exceeded. Thus in the event of a defect, no previous damage, prior to an event linked to an

excessive temperature.

  OBJECT OF THE INVENTION The object of the present invention is to remedy these drawbacks and to this end relates to a detection installation of the above type, characterized in that it comprises - a temperature element (D) which measures a temperature and provides a temperature signal (IB), - an amplification installation (T) which receives the temperature signal (UB) and provides an output signal (Ic), and - a recording installation (F) which receives the signal output (Ic) and in the case where the measured temperature exceeds a limit temperature, records in a non-fleeting manner a disturbance signal,

  the detection installation being monolithically integrated.

  The invention also relates to a characterized component

  in that the detection installation and at least one other circuit are integrated monolithically.

  Finally, the invention relates to a method characterized in that during the operating state of the monolithic component, a first detection installation is activated and in the event that a first operating temperature of the monolithic component exceeds a first limit temperature, a first disturbance signal in the first memory installation (F1) of the first detection installation, and at the end of the operating state, for a temperature below the first limit temperature, it is checked whether a disturbance signal is recorded in the first installation

record (Fl).

  This installation and this method according to the invention offer, with respect to the state of the art, the advantage of allowing a posteriori detection of an excessive temperature event produced during operation. This can advantageously be done with relatively small additional circuit means. In addition, the suitability for operation of the installation can be verified or advantageously guaranteed.

  detection according to the invention by checking or checking other detection installations used during a final measurement.

  The invention is based on the basic idea that in a monolithic integrator with a component to be controlled and thus with direct thermal coupling of excessive temperature events, during operation, it will not only be possible to measure but record in a recording installation (memory installation) non-volatile, preferably irreversibly. Non-volatile or fugitive recording no longer makes it possible to neutralize a signal possibly recorded during operation. Advantageously, the user of the component is thus not allowed any application with which it is possible to reset the recorded disturbed state. In addition, it can be advantageously provided that the user also has a possibility to read the memory installation and determine by detection if there has been an excessive temperature event. The irreversible recording according to the invention relates to 10 recordings which can no longer be canceled during the continuation of the operation even when it returns below the limit temperature. These recordings can no longer be neutralized even in normal applications of the circuits of the monolithic component. Advantageously, according to one use, no application or program is accessible which allows detection of the state of the installation.

  recording or monitoring the recording of a disturbing signal. This guarantees great safety so that during the subsequent analysis of the component, it will be possible to have guaranteed information indicating whether an excessive temperature event has excited during operation or not. As the detection installation according to the invention is supplied by the voltage supply terminals of the semiconductor component, events outside of the operating times do not modify the recording state of the recording installation.

  As an irreversible disturbance recording installation, a fuse can be used, in particular an element having a destructible conductive path, for example made of metal or polysilicon (polycrystalline silicon). other elements which change state irreversibly when subjected to an overcurrent such as for example a Zener diode which de30 becomes conductive in case of overcurrent (Zener switching) or a metal-oxide insulator which in case of overcurrent becomes conductive (switching oxide); in general in these components, the metal is melted in the event of breakdown by the tension so that after cooling,

  we will have a metallic conductive path.

  As a variant, it is also possible in principle to record in a programmable fixed memory (PROM) which cannot be erased by the operation of the component. You can use a PROM memory with several diodes (diode network) which during programming are

  burned by the amplification installation of the detection installation.

  As a temperature element, it is advantageously possible to use a pn junction mounted in the blocked direction, for example a diode mounted in the blocked direction and whose blocking current increases exponentially with temperature and thus ensures high sensitivity. As an amplification installation, the collector of a bipolar transistor can be used with, instead of a collector resistor, for example the recording or memory element which will be cut in the event of a disturbance so that the voltage of output taken from the collector provides information regarding the state of the recording element. In addition, instead of a transistor, a threshold switch can be used, for example a transistor combined with other components. According to the invention, it is possible to use in the detection component, several detection installations having different functions such as for example a first detection installation which records a first disturbance signal in the event of the temperature being exceeded during operation, a another detection installation which, during the correct final measurement, is activated by the manufacturer and registers a second disturbance signal. In addition, a third detection installation can be provided which, like the second detection installation, is only activated for the final measurement and has a stress threshold for recording a disturbing signal slightly above the final measurement temperature. and which must not be destroyed or during the

  neither during the final measurement.

  The additional detection installations of the monolithic component make it possible to ensure that the systematic dispersion of the stress thresholds of the detection installations is sufficiently low to guarantee proof of the excessive temperature event during operation and so that the final control of the monolithic component or the integrated chip was carried out at a correct final measurement temperature. Depending on this, a room overheated during operation, having after the correct final measurement, a first recorded disturbance signal and a second recorded disturbance signal, while the

  third disturbing signal will fail.

  Instead of a pn junction installed in the blocked direction, one can also provide a pn junction in the passing direction or for example a resistance depending on the temperature and then the case

  if necessary, due to the lower temperature sensitivity, it is possible to use amplification installations with several stages.

  Drawings The present invention will be described below in more detail with the aid of some embodiments represented in the appended drawings in which: FIG. 1 is a block diagram of a detection installation corresponding to a first mode embodiment, - FIG. 2 is a block diagram of a detection installation of another embodiment, - FIG. 3 is a block diagram of a detection installation of another embodiment, - FIG. 4 is a block diagram of a detection installation of another embodiment,

  - Figure 5 is a block diagram of a semiconductor component according to the invention with several detection installations according to the invention.

  Description of embodiments

  According to FIG. 1, a detection installation comprises a transistor T of the npn type with a diode D connected in the blocked direction between the connection of the operating voltage Ub and the base B of the transistor T so that the anode of the diode D is connected to the base of the transistor. The emitter of transistor T is connected to ground G. Between the operating voltage Ub and the collector K of transistor T there is a fuse F 25 which, when a limit current is exceeded, burns irreversibly by destroying a conductive path. A blocking current IB between the operating voltage terminal Ub and the base B of the transistor T, as base current IB of the transistor T defined by the current amplification coefficient, the collector current Ic passing through the fuse 30 F. The intensity IB here depends exponentially on the temperature. If a limit temperature is exceeded, the collector current Ic exceeds the limit current of the blown fuse F. This overcurrent event can be verified by the optical inspection of fuse F. Figure 2 shows an embodiment with a pnp type transis35 tor T which essentially corresponds to the embodiment of figure 1 with terminal exchange related to the operating voltage. In this embodiment, the transistor T is controlled by the blocking current of the diode D when the temperature is sufficiently

  high and if a limit temperature is exceeded, the collector current Ic passing through fuse F burns this fuse F. In this case also, an optical check makes it possible to note the event of overtemperature or overcurrent.

  The embodiments of FIGS. 3 and 4 represent other detection installations with respect to the embodiment of FIGS. 1 and 2, in which the collector K of the transistor T supplies, by an output terminal A, an output voltage Ua. The output terminals A are also connected by an ohmic resistor R each time to the operating voltage terminal not connected to the fuse F. Thus, on the output terminal A, in the event of a fuse F destroyed, there will be a voltage defined. In the detection installation of FIG. 3, in the basic state shown with a conductive fuse F, the terminal A will be at the operating voltage Ub; if the fuse F is destroyed, this terminal will be earthed G by the ohmic resistance R. In the embodiment of FIG. 4, with the extension with respect to FIG. 2, according to the ground state represented, the output terminal A will be earthed via the fuse F; as shown in Figure 3, across the ohmic resistor R there will be the operating voltage Ub. If fuse F is destroyed, after an overcurrent event, the output terminal A is connected to the operating voltage terminal B via the resistor

R so that we will have Ua = Ub.

  FIG. 5 shows a first detection installation 1, a second detection installation 2 and a third detection installation 3 with at least one other circuit 5, the operating state of which must be checked against overcurrent events ; these circuits are integrated into a monolithic component 4. The first detection installation i and the other circuit 5 are supplied by a common operating voltage Ub and these circuits are active in the operating state. The second detection installation 2 and the third detection installation 3 are not active during operation for example they are not connected to the operating voltage Ub and it is only after an additional measurement which cannot be ensured by the circuit 5 or by the other circuits of the component 4 which are connected to the operating voltage Ub. In the event of an overtemperature event during operation, as described above, the diode Dl constructs a temperature signal in transistor Tl which records a disturbance signal if the fuse Fl blows.

  During the final measurement before the component is supplied, the detection installations 2 and 3 are activated, the first detection installation 1 being out of service. The final measurement is carried out at a temperature slightly above the limit temperature of the second detection installation 2 and slightly below the third limit temperature of the third detection installation 3. If the final measurement is correct, a state will have been recorded of disturbance linked to the destruction of fuse F2 of the second detection installation 2 but not in the third detection installation 3. This will later prove that the final measurement has been overrated at the expected temperature and that the response points of the overcurrent fuse are correct. As an alternative to

  this embodiment, in principle for the second and the third detection installation D2, D3, it is also possible to use a common diode D as temperature element.

Claims (4)

CLAIMS ONS) Detection installation for an electronic component, characterized in that it comprises - a temperature element (D) which measures a temperature and provides a temperature signal (IB), - an amplification installation (T) which receives the temperature signal (UB) and provides an output signal (Ic), and - a recording installation (F) which receives the output signal (Ic) and in the case where the measured temperature exceeds a limited temperature , non-fleetingly records a disturbance signal, the detection installation being monolithically integrated. ) Detection installation according to claim 1, characterized in that it (F) records the disturbing signal irreversibly. ) Detection installation according to claim 2, characterized in that it (F) has a ground state and a disturbed state and to record the fault signal it irreversibly changes to the disturbed state. ) Detection installation according to claim 3, characterized in that the recording installation (F) has in its ground state, a conductive path which can be destroyed, preferably in a metal or polycrystalline silicon which will be destroyed in the event of disturbance. ) Detection installation according to claim 3, characterized in that in the fundamental state it comprises a diode (Zener) or an insulator, preferably a metal oxide insulator which, destroyed, goes to a conductive state.   6) detection installation according to claim 1, characterized in that   the amplification installation (T) controls the output current (Ic) passing through the recording installation (F) as a function of the temperature signal (IB).   ) Detection installation according to claim 6 characterized in that the amplification installation comprises a bipolar transistor (T) whose basic circuit is connected to the temperature element (D) and whose collector circuit comprises recording installation (F). 8) detection installation according to claim 7, characterized in that the recording installation (F) is provided between the collector (K) of the   bipolar transistor (T) and an operating voltage terminal (Ub, G).   ) Detection installation according to claim 8, characterized in that the bipolar transistor (T) is an npn transistor, the recording installation (F) is installed between the positive voltage terminal of   operation (Ub) and the collector (K), and the emitter (E) of the bipolar transistor is connected to ground.    ) Detection installation according to claim 8, characterized in that the bipolar transistor is a pnp transistor (T), the recording installation (F) is connected between the collector (K) and the terminal of   ground (G), and the emitter (E) of the bipolar transistor (T) is connected to a positive terminal of the operating voltage (Ub).   ) Detection installation according to any one of claims 8 to 10,   characterized in that an output terminal (A) is connected to the collector of the bipolar transistor (T)   to read an output voltage (Ua).   ) Detection installation according to any one of claims 8 to 11,   characterized by an ohmic resistance (R) between the collector (K) of the bipolar transistor   (T) and the operating voltage terminal (Ub, G) not connected to the recording installation (F).   13) detection installation according to claim 1, characterized in that the temperature element is a semiconductor element including a   diode (D), mounted in the blocking direction.   ) Detection installation according to claim 1, characterized in that   the temperature element is a semiconductor connected in the passing direction, in particular a diode or a resistance depending on the temperature.    ) Monolithic component having at least one detection installation according to any one of claims 1 to 14 and at least one other circuit,   characterized in that the detection installation and at least one other circuit are integrated monolithic way.   ) Monolithic component according to claim 15, characterized in that it comprises at least a first detection installation (D1) capable of being activated by the voltage connection terminal (Ub, G), with a first limit temperature and a first recording installation   (F1) for an operating measurement, and a second detection installation (D2) with a second limit temperature and a second recording installation (F2) for a final measurement, the second detection installation (D2) being activated independently of the first detection installation (Dl) preferably only outside of the operating measurement and / or not by the other circuit.   17) Monolithic component according to claim 16, characterized by a third detection installation (D3) with a third limit temperature and a third recording installation (F3) for the final measurement,   the third temperature limit being higher than the second temperature limit and the second and the third detection installation being activated jointly.   ) Method for detecting an overtemperature event of a monolithic component according to any one of claims 15 to 17,   characterized in that during the operating state of the monolithic component (4), a   first detection installation according to any one of claims 1 to 14 is activated and in the event that a first operating temperature of the monolithic component (4) exceeds a first limit temperature, a first disturbance signal is recorded in the first memory installation (FI) of the first detection facility, and   at the end of the operating state, for a temperature below the first limit temperature, it is checked whether a disturbance signal is recorded in the first recording installation (Fl).   19) Method according to claim 18, characterized in that   a monolithic component is checked according to any one of claims 16 or 17 and before the implementation of the monolithic component, a final measurement is carried out, the first detection installation not being activated and the second detection installation (2 ) being activated, and preferably also the third detection installation (3) is activated and   a final temperature measurement is carried out above the second limit temperature and preferably below the third limit temperature, and during a following control step, it is checked whether the second memory installation (F2) and the if applicable also the third installation   memory (F3) contain a disturbance signal.