JPS6042623A - Temperature detecting circuit - Google Patents

Abstract

PURPOSE:To incorporate a temperature detecting circuit in a semiconductor chip easily by making the relative values of voltages applied to both input terminals of a voltage comparator correspond to temperature variation, and inverting the operation state of the voltage comparator when the temperature variation attains to a specific value. CONSTITUTION:A low level signal is supplied to a control terminal 5 after a power source is turned on to hold the collector potential of a transistor (TR) Q6, i.e. potential of an output 6 lower than base potentials VR and VT temporarily, and thus a TRQ3 is turned on and then the terminal 5 is held at a high level again, placing a temperature detecting circuit in readiness. If the junction temperature of the chip rises up to a detection temperature in said state, the relative value of the base potential is ¦VT-VR¦ 0, and a current flows to a TRQ1; and the current of the TRQ3 decreases accordingly and the potential at the output terminal 6 rises to turn on a TRQ2 abruptly, and the TRQ3 is turned off to hold the output terminal 6 at the high level, detecting the junction temperature of the chip being higher than the detection temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a temperature detection circuit for detecting that the temperature has reached a predetermined value, and particularly relates to a temperature detection circuit that is packaged to be incorporated into an integrated circuit.

[Prior art]

Integrated circuits in general, and logic integrated circuits in particular, are widely used in many information processing devices such as combinators, and preventing malfunctions and destruction of these logic integrated circuits due to heat is one of the most important issues. Recently, speeding up and L
As integration progresses, power consumption per integrated circuit increases.
Furthermore, its importance is increasing as the cooling method for equipment is being switched from air cooling to liquid cooling.

Therefore, there is an increasing need for a temperature detection mechanism that can detect an abnormal temperature rise in an integrated circuit chip at an early stage and respond by issuing a warning or cutting off the power supply.

Conventionally, in computers etc. that have a large number of integrated circuits, the means to detect abnormal temperature rises in these integrated circuits has been to mount a component such as a thermostat at any location within the device and monitor the temperature of that part. However, indirect measures are taken, such as monitoring fan rotation speed to detect temperature rises, but this makes it impossible to detect temperature rises in individual integrated circuit chips. However, in future devices, rather than detecting the average temperature rise of multiple integrated circuits, it will be better to detect the temperature of each integrated circuit, where each integrated circuit chip has its own temperature rise. Although this is important, it is technically difficult to incorporate a temperature detection circuit into an integrated circuit chip due to space constraints.
Its development has been awaited.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a specific temperature detection circuit to be built into an integrated circuit chip.

[Structure of the invention]

In order to achieve such an invention, this invention supplies voltages generated by power supplies with different temperature characteristics to the inputs of the voltage comparator, and when the power is turned on, the voltage comparator receives a signal supplied from the outside. The initial state is set by
The temperature characteristics and circuit constants of the power supply are determined so that the operating state of the voltage comparator is reversed when the amount of temperature change reaches a predetermined amount. Hereinafter, the present invention will be described in detail using drawings showing embodiments.

[Embodiments of the invention]

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the figure, 1 is a first power supply that outputs a voltage according to temperature changes, 2 is a voltage comparator with a latch function, 3 is a second power supply that is connected to the reference power supply, and 4 is the initial stage of voltage comparator 2. A control circuit sets the state, 5 is a control terminal for supplying a control signal from the outside to set the initial state of the voltage comparator l, and 6 is an output terminal.

Figure 2 is a detailed circuit diagram of Figure 1, with the diode D1
, Dg and resistor R1 constitute power supply 1, p1 transistor Qs tQx tQs, resistor R and constant current source C8I
The voltage comparator 2f is constructed by the following, the reference voltage vl generating circuit is shown by the block 3 and the control circuit 4 is comprised of a transistor Q4 +Qs rQ8, a resistor R3, and a constant current source cS2.

Now, the detected temperature when the chip junction temperature TJ rises under abnormal conditions is T9. shall be. Under normal conditions, that is, when the chip junction temperature T,1 is lower than the detection temperature Tc, the base potential V of the transistor QH is the same as the transistor Q.
The resistance value and current rating of the diode are determined so that it is lower than the base potential vl of No. 3. Since the forward voltage Vv of the diode has a negative temperature coefficient, the pace potential Vd of the transistor Q1 increases as the temperature rises. On the other hand, the base potential vlI of the transistor Qs is set to have a constant or negative temperature coefficient with respect to temperature change, or a temperature rise coefficient smaller than the base potential VT.

That is, each constant is determined so that the relative value IVT-Vll of the base potential becomes smaller as the temperature rises.

Two voltage comparators At normal temperature, the base potential ■1 is lower than the base potential vl, so the transistor Qs
is in a conductive state, transistors Ch and Q* are in a cut-off state, and a low level output signal ■ is output to the output terminal 6. L is sent out, and the output signal ■. Ltj:)? Even when the y resistor Q is in the cutoff state, the base potential ■T.

It is set to be lower than v. Now, the voltage comparator 2 has a base potential of V immediately after the power supply VIg is turned on.

, vl, the transistor Q1 always becomes conductive, and does not operate as a temperature detection circuit up to i. Therefore, after turning on the power, a low level signal is given to the control terminal 5, and the collector potential of the transistor Q6, that is, the output 6
After lowering the potential of the transistor Qs to a conductive state by lowering the potential of the transistor Qs to a value lower than the base potential vR9vT, the terminal 5 is returned to a high level, thereby indicating that the temperature detection circuit is ready to operate. In this state, when the junction temperature T of the chip rises and reaches the detection temperature Tc, the relative value of the base potential becomes 0 in 1Vt-Vi+I.
1 also flows, the current in transistor Q3 decreases by that amount, the potential at output terminal 6 rises, and then transistor Q! suddenly becomes conductive, and transistor 9
It can be detected that the output terminal 6 becomes high level and the chip junction temperature Tj becomes higher than the detected temperature Te. Figure 3 illustrates these things, with the temperature on the horizontal axis and the potential at each point on the vertical axis, showing the state in which the output voltage of the voltage comparator 2 suddenly changes after the detected temperature Tc. It shows.

Fig. 4 shows another embodiment, and the operation principle is the same as Fig. 2, so the explanation is omitted. At normal temperature, transistor Q1 is in a conductive state and the output signal is at a high level, and at abnormal temperature, the output signal is at a high level. The difference from the case in FIG. 2 is that the level is low.

〔Effect of the invention〕

As explained above, the temperature detection circuit according to Jin's invention makes the relative value of the voltage supplied to both input terminals of the voltage comparator correspond to the temperature change, and when the temperature change reaches a predetermined amount, the voltage comparator operates. Because it can be done with something that reverses the state,
In addition to being able to detect temperature, since each element is composed of a resistor and a conductor, it can be easily incorporated into a conductor chip.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is a detailed circuit M11s diagram thereof, and Fig. 4 is a graph showing changes in the output voltage of the voltage comparator. Fig. 4 shows another embodiment. It's a circuit diagram. 1.3...Power supply, 2...Voltage comparator, 4...
・Output terminal, R1-R4...Fist/Resistance, D! ~Ds I
・・・Diode, Qt ~ Qs Φ・Cool・Transistor, C8s, C8z ・・ Constant current source. Figure 3 Tc T+ Figure 4 L-J 14C

Claims (1)

[Claims] A voltage comparator, a first power supply that supplies voltage to one input terminal of this voltage comparator, a second power supply that supplies voltage to the other input terminal of the voltage comparator, and a second power supply that supplies voltage from the outside when the power is turned on. a control circuit that sets the operating state of the voltage comparator to a predetermined initial state by control No. 11, which is
and a temperature detection circuit characterized in that the relative value of the voltage output from the second power supply changes so as to reverse the operating state of the voltage comparator when the temperature change reaches a predetermined amount.