JP2001141572A - Microcomputer and chip temperature detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microcomputer and a chip temperature detecting method for properly detecting a chip temperature. SOLUTION: This microcomputer provided with a reference voltage generating circuit constructed of a constant-current circuit 2a having no temperature dependence, a resistor 3, and a MOS transistor switch 4 for producing a reference voltage 7 and a comparison voltage generating circuit constructed of a constant-current circuit 2b with a temperature dependence, a resistor 3 and a MOS transistor switch 4 for generating a comparison voltage 8 is also provided with a comparator 9 comparing the dimensions of the reference voltage 7 and the comparison voltage 8 mutually and outputting a detection signal 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcomputer having a chip temperature detecting function.

[0002]

2. Description of the Related Art A conventional microcomputer (hereinafter referred to as M
CU), a circuit for measuring the chip temperature of the MCU is not particularly mounted. Also, M
In general, the transistors constituting each circuit of the CU lose their current driving capability as the temperature rises, but the additional capacitance does not change in temperature, so that the operation speed decreases at a high temperature.

Therefore, in the circuit design of the MCU, in order to guarantee the operation at the maximum operating frequency within the operation guarantee temperature range,
In order to have a sufficient operation margin at high temperatures, it is necessary to increase the transistor size of the circuit to increase the current driving capability.

[0004] However, when a transistor is designed for operation at high temperature, the operation speed increases at normal temperature / low temperature due to the increase in current driving capability of the circuit. Is large, the fluctuation width of the internal power supply voltage may increase, which may cause power supply noise and increase the current consumption value inside the MCU.

[0005] The prior art disclosed in Japanese Patent Application Laid-Open No.
There are JP-A-5-24655, JP-A-57-28227 and JP-A-60-25426. These prior arts use a temperature dependency of a resistor or a diode receiving a constant current from a constant current circuit as a variable element for obtaining a temperature detection signal, and have a configuration. However, it is complicated and cannot detect an appropriate temperature for the chip temperature. That is, Japanese Patent Application Laid-Open No. 55-24655 utilizes the fact that the resistance itself changes with temperature.
Japanese Unexamined Patent Publication No. 57-28227 utilizes the fact that the paired resistors have different temperature coefficients. Japanese Patent Application Laid-Open No. 60-25426 utilizes the temperature dependence of a diode.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a microcomputer and a chip temperature detecting method capable of appropriately detecting a chip temperature so that a transistor size suitable for a chip temperature can be selected. It is.

[0007]

A microcomputer according to a first aspect of the present invention includes a first constant current circuit having no temperature dependency and a second constant current circuit having temperature dependency as circuit elements. Temperature detection means for comparing the magnitudes of signals according to the currents flowing through the first and second constant current circuits and outputting a detection signal is provided as a circuit element.

In the microcomputer according to the second aspect of the present invention, the first constant current circuit having no temperature dependency, the second constant current circuit having temperature dependency, and the current flowing through the first constant current circuit are provided. A reference voltage generating means for generating a reference voltage in response to the reference voltage and a comparison voltage generating means for generating a comparison voltage in response to a current flowing through the second constant current circuit. Temperature detecting means for comparing the magnitude of the signal and outputting a detection signal is provided as a circuit element.

In a microcomputer according to a third aspect of the present invention, there is provided a reference voltage generating means including a constant current circuit having no temperature dependency, a reference voltage generating circuit including a resistor and a MOS transistor switch, and generating a reference voltage; A comparison voltage generating means comprising a constant current circuit having a characteristic, a resistance and a MOS transistor switch, and a comparison voltage generation circuit for generating a comparison voltage, as circuit elements;
Temperature detecting means comprising a comparator for comparing the voltage signal of the reference voltage and the voltage signal of the comparison voltage and outputting a detection signal is provided as a circuit element.

In a microcomputer according to a fourth aspect of the invention, the first constant current circuit is constituted by a band gap type constant current circuit, and the second constant current circuit is constituted by a threshold difference type constant current circuit. is there.

In the microcomputer according to a fifth aspect of the present invention, the detection signal is derived from the temperature detection means in accordance with the enable signal applied at a predetermined timing.

In the microcomputer according to the sixth aspect, only when the enable signal input to the MOS transistor switch and the comparator is at the valid signal level,
An operating current is generated in the MOS transistor switch and the comparator, and a detection signal is derived from a temperature detecting means including the comparator.

In a microcomputer according to a seventh aspect of the present invention, the temperature detecting means including the comparator holds the detection signal when the enable signal is at the valid signal level.

In the microcomputer according to the eighth invention, the detection signal from the temperature detecting means can be changed by changing the reference voltage by the reference voltage generating means by switching the conduction / non-conduction of the MOS transistor switch. Things.

In a microcomputer according to a ninth aspect of the present invention, a constant current circuit, a plurality of resistance elements for flowing the current of the constant current circuit, and a conduction control MOS for controlling conduction / disconnection of a current flowing through the resistance element. A transistor switch; and a bridge control MOS transistor switch for bridging the resistance element, wherein the reference voltage is generated by a voltage drop due to a current flowing through the resistance element, and a bridge control for bridging the resistance element is provided. The reference voltage can be adjusted by controlling conduction / non-conduction of a MOS transistor switch.

In the microcomputer according to the tenth aspect, the detection signal from the temperature detection means can be changed by changing the comparison voltage by the comparison voltage generation means by switching the conduction / non-conduction of the MOS transistor switch. Things.

In a microcomputer according to an eleventh aspect of the present invention, the constant current circuit, the plurality of resistance elements that allow the current of the constant current circuit to flow, and the flow of the current flowing through the resistance element.
A current-controlling MOS transistor switch for controlling interruption, and a bridging control MOS transistor switch for bridging the resistance element, wherein a comparison voltage is generated by a voltage drop caused by a current flowing through the resistance element; The comparison voltage can be adjusted by controlling the conduction / non-conduction of a bridge control MOS transistor switch that bridges the above.

In the microcomputer according to the twelfth aspect, a predetermined enable signal program is written, and an enable signal register for generating an enable signal by the enable signal program is provided.

In the microcomputer according to the thirteenth aspect, the enable signal is written in the enable signal register by an operation program for operating each element of the microcomputer.

In the microcomputer according to the fourteenth aspect, the register for the enable signal is integrated as an integrated circuit element in the chip of the microcomputer.

In a microcomputer according to a fifteenth aspect, an enable signal is generated by writing a program to a monitoring timer register.

In a microcomputer according to a sixteenth aspect, an enable signal is generated by writing a program into a monitoring timer register integrated as an integrated circuit element in a microcomputer chip. .

In the microcomputer according to the seventeenth aspect, an operation program for operating each element of the microcomputer writes the enable signal into the monitoring timer register.

In the microcomputer according to the eighteenth aspect, an enable signal timer for generating an enable signal is provided.

In the microcomputer according to the nineteenth aspect, the enable signal timer is integrated as an integrated circuit element in the microcomputer chip.

In the chip temperature detecting method according to the twentieth aspect, a signal corresponding to a current flowing through the first constant current circuit having no temperature dependency provided on the microcomputer chip and a signal provided on the microcomputer chip are provided. The chip temperature is detected by obtaining a detection signal by comparing the magnitude with a signal corresponding to the current flowing through the second constant current circuit having the temperature dependency.

In the chip temperature detecting method according to the twenty-first aspect, the reference voltage generated according to the current flowing through the first constant current circuit having no temperature dependency provided on the chip of the microcomputer, and A chip temperature is detected by comparing a voltage signal with a comparison voltage generated according to a current flowing through a second constant current circuit having a temperature dependency provided on a chip to obtain a detection signal and obtaining a detection signal. It was done.

In a chip temperature detecting method according to a twenty-second aspect, a detection signal is derived in accordance with an enable signal applied at a predetermined timing to detect a chip temperature.

In the chip temperature detecting method according to the twenty-third aspect, a detection signal is derived in accordance with an enable signal at an effective signal level to detect a chip temperature, and when the enable signal is not at an effective signal level, the detection signal is output. Without deriving, the detection signal when the enable signal is at the effective signal level is held.

In the chip temperature detecting method according to the twenty-fourth aspect, the detection signal for detecting the chip temperature is changed by changing the signal value of the reference voltage.

In the chip temperature detecting method according to the twenty-fifth aspect, the detection signal for detecting the chip temperature can be changed by changing the signal value of the comparison voltage.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a connection diagram showing a configuration of a chip temperature detection circuit according to the first embodiment of the present invention. The outline of the operation of the chip temperature detection circuit will be described with reference to the circuit diagram shown in FIG. In the figure, 1 is a power supply, 2a and 2b are constant current circuits as constant current sources, 3 is a resistor, 4 is a MOS transistor switch, 5
Is a ground portion (hereinafter referred to as GND), 6 is an enable signal, 7 is a reference voltage, 8 is a comparison voltage, 9 is a temperature detecting means including a comparator, and 10 is a detection signal.

The power supply 1 is connected to constant current circuits 2a and 2b. The constant current circuits 2a and 2b have a function of generating a constant current. The resistor 3 has a function of generating a voltage determined by resistance × constant current as a voltage drop caused by the resistance value of the constant current generated by the constant current circuits 2a and 2b.

One input of the MOS transistor switch 4 has GND 5 and its control signal has an enable signal 6.
However, a resistor 3 is connected to the other input. When the enable signal 6 is at the “Hi” signal level, the MOS transistor switch 4 conducts between the two inputs, so that a constant current generated by the constant current circuit 2 is supplied to the power supply 1-1.
It flows between GND 5 and has a function of generating a constant voltage by the resistor 3. When the enable signal 6 is at the “Low” signal level, the MOS transistor switch 4 cuts off the current flowing between the power supply 1 and the GND 5 by cutting off between the two inputs, so that the resistor 3 does not generate a constant voltage. Also has work. In the MOS transistor switch 4, the meaning of the signal level of the enable signal 6 is reversed, and when the enable signal 6 is at the “Low” signal level, conduction is provided between the two inputs, and the enable signal 6 is at the “Hi” signal level. In some cases, it is needless to say that the circuit can be configured to cut off between the two inputs.

Here, the constant current circuit 2a is a circuit having no temperature dependency, and the constant current circuit 2b is formed of a circuit having temperature dependency. As these constant current circuits 2a, circuits having no temperature dependency can be created by using, for example, a band gap type constant current circuit. Further, the constant current circuit 2b
When a threshold difference type constant current circuit is used, the threshold value of the MOS transistor has a negative temperature dependence, so that a circuit having a negative temperature dependence can be created. At this time, the voltage generated by the resistor 3 of the circuit of the constant current circuit 2a is equal to the reference voltage 7
And the voltage generated by the resistor 3 of the circuit of the constant current circuit 2b is the comparison voltage 8.

The temperature detecting means composed of the comparator 9
It has a function of receiving the reference voltage 7 and the comparison voltage 8 and generating a detection signal 10 by comparing the two voltages. For example, when the comparison voltage 8 is higher in voltage than the reference voltage 7, "H
The detection signal 10 having the “i” signal level can be generated, and the detection signal 10 having the “Low” signal level can be generated when the comparison voltage 8 is lower than the reference voltage 7.

The voltage comparison operation of the comparator 9 is effective only when the enable signal 6 is at the "Hi" signal level. Further, the comparator 9 has a latch inside and takes in the detection signal 10 generated when the enable signal 6 is at the “Hi” signal level, and the enable signal 6 becomes the “Low” signal level, and the voltage of the comparator 9 is compared. Even if the operation becomes invalid, the “Hi” signal level of the detection signal 10 can be held.

A constant current circuit 2a composed of a band gap type constant current circuit, a constant current circuit 2b composed of a threshold difference type constant current circuit, a resistor 3, a MOS transistor switch 4, and a comparator 9. Each of the temperature detecting means constitutes a circuit element of the microcomputer, and these circuit elements are integrally integrated as an integrated circuit element in a chip of the microcomputer.

With these circuit configurations, when the chip temperature is low when the enable signal 6 is set to the "Hi" signal level, the current of the constant current circuit 2b is large. The voltage value increases, and the detection signal 10 becomes the “Hi” signal level. Enable signal 6
When the chip temperature is high when is set to the “Hi” signal level, since the current of the constant current circuit 2b is small, the voltage value of the comparison voltage 8 is smaller than the reference voltage 7 and the detection signal 10 is “Low”. Signal level.

As described above, the chip temperature can be detected by comparing the reference voltage 7 and the comparison voltage 8, and for example, a plurality of transistors for driving a data bus in the MCU are prepared according to the signal level of the detection signal 10. When the detection signal 10 is at the "Hi" signal level (low temperature), only some of the transistors are operated and the remaining transistors are not operated, and when the detection signal 10 is at the "Low" signal level (high temperature), the transistor is prepared. By operating all the transistors, it is possible to drive the bus with the same drive capability at low to high temperatures.

According to the first embodiment of the present invention, the reference voltage 7 is generated by the constant current circuit 2a having no temperature dependency, constituted by the band gap type constant current circuit, the resistor 3, and the MOS transistor switch 4. A reference voltage generating means comprising a reference voltage generating circuit, a constant current circuit 2b having a temperature dependency formed by a threshold difference type constant current circuit, a resistor 3, and a MOS transistor switch 4. A comparison voltage generation means comprising a comparison voltage generation circuit for generating a circuit element, and a temperature detection means comprising a comparator 9 for comparing a voltage signal of the reference voltage 7 and a voltage signal of the comparison voltage 8 and outputting a detection signal as a circuit element And a circuit element including the constant current circuits 2a and 2b, the resistor 3, the MOS transistor 4, and the comparator 9 The MOS transistor switch 4 is integrated only as an integrated circuit element of the microcomputer chip, and only when the enable signal 6 inputted to the MOS transistor switch 4 and the comparator 9 at a predetermined timing is, for example, "Hi" and at an effective signal level. An operating current is generated in the comparator 9 and a detection signal is derived from the temperature detecting means including the comparator 9. The enable signal 6 input to the MOS transistor switch 4 and the comparator 9 is, for example, “Low” and becomes an effective signal level. When there is no operation current, no operating current is generated in the MOS transistor switch 4 and the comparator 9, and the detection signal is not derived from the temperature detecting means comprising the comparator 9, but the temperature detecting means comprising the comparator 9 makes the enable signal 6 of the valid signal level Time detection signal And a constant current circuit 2a as a constant current source having no temperature dependency constituted by a bandgap type constant current circuit, so that a transistor size suitable for the chip temperature can be selected. Using a constant current circuit 2b as a constant current source having a temperature dependence constituted by a value difference type constant current circuit, and utilizing the temperature dependence characteristics of these constant current circuits themselves,
With the circuit elements incorporated in the integrated circuit, it is possible to obtain a microcomputer that can appropriately detect a chip temperature and can accurately derive a temperature detection signal while suppressing current consumption by control using an enable signal.

According to the first embodiment of the present invention, the reference voltage generated according to the current flowing through the first constant current circuit having no temperature dependency provided on the chip of the microcomputer, and The chip temperature is detected by comparing the magnitude of a voltage signal with a comparison voltage generated in accordance with a current flowing through a second constant current circuit having temperature dependency provided in the chip to obtain a detection signal. A detection signal is derived in accordance with an enable signal at an effective signal level applied at a predetermined timing to detect a chip temperature, and when the enable signal is not at the effective signal level, the detection signal is not derived, and the enable signal is not derived. Holds the detection signal when the signal is at the effective signal level, so that the transistor size can be selected according to the chip temperature. Made, it is possible to obtain a chip temperature detection method that allows a proper detection of the chip temperature with a low current consumption.

Embodiment 2 FIG. 2 is a diagram showing a configuration of a reference voltage generating circuit according to a second embodiment of the present invention. In the figure, 1 is a power supply, 2a is a constant current circuit as a constant current source, 3 is a resistor, 4 is a MOS transistor switch, 5 is GND, 6 is an enable signal, and 7 is a reference voltage.

The reference voltage generating circuit according to the second embodiment includes the power supply 1 and the constant current circuit 2 according to the first embodiment shown in FIG.
a, a resistor 3, and a MOS transistor switch 4. The comparator 9 and the power source 1, the constant current circuit 2b, the resistor 3, Together with the comparison voltage generating circuit composed of the MOS transistor switch 4, it constitutes a chip temperature detecting circuit in the microcomputer.

In the second embodiment, a plurality of resistors 3 are connected between the constant current circuit 2 and the Nch type MOS transistor 4, and a MOS transistor switch 4 is connected in parallel with each resistor 3. . The reference voltage 7 is output from the connection between the uppermost resistor 3 and the constant current circuit 2.

Here, the resistance of the MOS transistor switch 4 connected in parallel with the turned on MOS transistor switch 4 becomes sufficiently smaller than the resistance 3 because the resistance of the MOS transistor switch 4 itself is sufficiently small. A large resistance is connected in parallel, and the resistance in this part is substantially equal to the conduction resistance of the MOS transistor switch 4. This is an effect equivalent to the absence of the resistor 3. Also,
The resistance value of the resistor 3 connected in parallel to the non-conductive MOS transistor switch 4 is the resistance value of the resistor 3 itself.

Therefore, the total resistance value of the resistors 3 connected in parallel to the MOS transistor switch 4 which is turned off is the resistance value of this circuit, and the reference voltage 7 is a voltage of this resistance value × constant current value. By switching the conduction / non-conduction of the MOS transistor switch 4, the voltage value of the reference voltage 7 can be changed.

FIG. 3 is a diagram showing a change in the detected temperature when the reference voltage 7 is changed in this way. The horizontal axis of this figure represents the temperature, the left side being low temperature and the right side being high temperature. The vertical axis represents the voltage.

The reference voltage 7 is a straight line graph parallel to the horizontal axis because there is no temperature dependency, but the comparison voltage 8 is a straight line graph falling to the right because it has a negative temperature characteristic. The temperature at the intersection of these two straight lines is the temperature detected by this circuit. That is, at a temperature lower than the temperature of the intersection, the detection signal 10 has a “Hi” signal level, and at a temperature higher than the temperature of the intersection, the detection signal has a “Low” signal level.

In this embodiment, the reference voltage 7 can be changed by switching the conduction / non-conduction of the MOS transistor switch 4, and the voltage value can be changed like the reference voltage A or the reference voltage B. Therefore, the intersection of the straight line graph can be changed as shown in the figure, and the set detected temperature in this circuit is changed to the temperature Ta or T
It can be changed like b.

That is, the MOS transistor switch 4
When the reference voltage 7 is set as the reference voltage A corresponding to the temperature Ta by setting the conduction / non-conduction switching of the reference voltage A, the comparison voltage 8 having a negative temperature characteristic decreases as the temperature rises. By reaching the intersection, the temperature T
a is to be detected. Further, when the reference voltage 7 is set as the reference voltage B corresponding to the temperature Tb by setting the conduction / non-conduction of the MOS transistor switch 4, the comparison voltage 8 having a negative temperature characteristic decreases as the temperature rises. , The temperature Tb is detected by reaching the intersection with the reference voltage B.

According to the second embodiment of the present invention, the constant current circuit 2a, the plurality of resistance elements 3 that flow the current of the constant current circuit 2a, and the energization that controls the energization / interruption of the current flowing through the resistance element 3 Control MOS transistor switch 4
And a bridging control MOS transistor switch 4 for bridging the resistive element 3. The bridging control MOS transistor switch 4 generates a reference voltage 7 by a voltage drop due to a current flowing through the resistive element 3 and bridges the resistive element 3. Since the reference voltage 7 can be adjusted by controlling the conduction / non-conduction of the MOS transistor switch 4, the set detection temperature can be changed by adjusting the reference voltage 7, and the transistor size can be selected according to the chip temperature. Thus, an appropriate chip temperature detection signal according to the purpose of use can be obtained.

Further, according to the second embodiment of the present invention, the detection signal for detecting the chip temperature is changed by changing the signal value of the reference voltage. By changing the set detection temperature, it is possible to perform appropriate chip temperature detection according to the purpose of use so that selection of a transistor size suitable for the chip temperature becomes possible.

Embodiment 3 FIG. FIG. 4 is a diagram showing a configuration of a comparison voltage generating circuit according to a third embodiment of the present invention. In the figure, 1 is a power supply, 2b is a constant current circuit as a constant current source, 3 is a resistor, 4 is a MOS transistor switch, 5 is GND, 6 is an enable signal, and 8 is a comparison voltage.

The reference voltage generating circuit according to the third embodiment includes the power supply 1 and the constant current circuit 2 according to the first embodiment shown in FIG.
b, a resistor 3, and a MOS transistor switch 4. The comparator 9 and the power source 1, the constant current circuit 2a, the resistor 3 and the comparator 9 are the same as those in the first embodiment shown in FIG. Together with the reference voltage generating circuit composed of the MOS transistor switch 4, it constitutes a chip temperature detecting circuit in the microcomputer.

In this embodiment, the second embodiment
Has the same configuration as that of the above circuit, and the voltage to be taken out is only the comparison voltage 8. Therefore, as in the second embodiment, the MOS transistor switch 4 is turned off.
The total resistance value of the resistors 3 connected in parallel to the circuit becomes the resistance value of this circuit, and the comparison voltage 8 becomes a voltage of this resistance value × constant current value. The voltage value of the comparison voltage 8 can be changed.

FIG. 5 is a diagram showing a change in the detected temperature when the comparison voltage 8 is changed in this way. The horizontal axis and the vertical axis in this figure are the same as those in FIG. 3, and the horizontal axis in this figure represents the temperature, with the left side being low temperature and the right side being high temperature. The vertical axis represents the voltage. In this embodiment, M
Since the comparison voltage 8 can be changed by switching the OS transistor switch 4, the voltage value can be changed like the comparison voltage A or the comparison voltage B. Therefore, the intersection of the straight line graph is shown in the figure. And the detected temperature in this circuit can be changed.

According to the third embodiment of the present invention, the constant current circuit 2b, the plurality of resistance elements 3 for flowing the current of the constant current circuit 2b, and the energization for controlling the energization / interruption of the current flowing through the resistance element 3 Control MOS transistor switch 4
And a bridging control MOS transistor switch 4 for bridging the resistive element 3. The bridging control MOS transistor switch 4 generates a comparison voltage 8 by a voltage drop due to a current flowing through the resistive element 3, and bridges the resistive element 3. Since the comparison voltage 8 can be adjusted by controlling the conduction / non-conduction of the MOS transistor switch 4, the setting detection temperature can be changed by adjusting the comparison voltage 8, and the selection of the transistor size adapted to the chip temperature Thus, an appropriate chip temperature detection signal according to the purpose of use can be obtained.

According to the third embodiment of the present invention, the detection signal for detecting the chip temperature can be changed by changing the signal value of the comparison voltage. By changing the set detection temperature, it is possible to perform appropriate chip temperature detection according to the purpose of use so that selection of a transistor size suitable for the chip temperature becomes possible.

Embodiment 4 FIG. 6 is a diagram showing a configuration of an enable signal generating circuit according to the fourth embodiment of the present invention. In the figure, 6 is an enable signal, 11 is a temperature judgment register, and 12 is a write signal.

In this embodiment, when writing is performed to the temperature determination register 11 in the MCU by a program for operating the MCU, a write signal 12 generated by the MCU is input to the temperature determination register 11, The enable signal 6 is generated from the temperature determination register 11.

By generating the enable signal 6 with this configuration, it is possible to set the conditions for detecting the temperature by the program for operating the MCU.

According to the fourth embodiment of the present invention, the enable signal is written in the enable signal register by the operation program for operating each element of the microcomputer, and the enable signal register is integrated on the chip of the microcomputer. Since it is integrated as a circuit element, an enable signal can be generated reliably and easily by writing an enable signal by using a program for operating a microcomputer, and a register for an enable signal is integrated in a chip of the microcomputer. As a result, the chip temperature can be appropriately detected by a configuration integrated with the chip.

Embodiment 5 FIG. 7 is a diagram showing another embodiment of the enable signal generation circuit according to the present invention. In the figure, 6 is an enable signal, 12 is a write signal, and 13 is a monitoring timer register.

In this embodiment, when writing is performed to the monitoring timer register 13 existing in the MCU by a program that operates the MCU, a write signal 12 generated by the MCU is input to the monitoring timer register 13. Thereby, the enable signal 6 is generated from the monitoring timer register 13.

The monitoring timer is a circuit existing in the MCU for preventing a program from running out of control. When a count overflow occurs, a monitoring timer interrupt occurs in the MCU. However, when writing to the monitoring timer register 13, the count is initialized at that point. For this reason, the user of the MCU creates a program so that writing to the monitoring timer register 13 occurs at regular intervals in the program.

By making such a program,
When the program is operating normally, writing to the monitoring timer register 13 occurs at regular intervals, and
The MCU operates normally because the monitoring timer existing in the CU is initialized at every writing, but the program runs away for some reason and the monitoring timer register 13
When writing to the CPU stops, the monitoring timer of the MCU counts over and a monitoring timer interrupt is generated, and a runaway handling process is performed inside the MCU (for example, MCU reset).

In this embodiment, the enable signal 6 is generated by writing to the monitoring timer register 13, so that the chip temperature can be detected after a certain period by the MCU program. Can create a program without being aware of temperature measurement. Furthermore, since an existing MCU internal register can be allocated, an additional register circuit is not required.

According to the fifth embodiment of the present invention, the enable signal is generated in the monitoring timer register integrated as an integrated circuit element in the microcomputer chip by the operation program for operating each element of the microcomputer. Since the enable signal is generated by this writing, the enable signal can be generated reliably and easily, and the detection of the chip temperature can be appropriately performed in a configuration integrated with the chip. Can be.

Embodiment 6 FIG. FIG. 8 is a diagram showing another embodiment of the enable signal generating circuit for generating the enable signal 6 in the present invention. In the figure, 6 is an enable signal and 14 is a timer.

In this embodiment, a timer 14 is provided in the MCU, and the timer 14
Generates the enable signal 6, the chip temperature can be detected at regular intervals of the MCU operation.

According to the sixth embodiment of the present invention, the enable signal timer for generating the enable signal is provided, and the enable signal timer is integrated as an integrated circuit element in the microcomputer chip. The enable signal can be reliably generated, and the chip temperature can be appropriately detected by integrating the enable signal timer with the chip by integrating the enable signal timer as an integrated circuit element in the microcomputer chip.

By creating a chip temperature detection circuit combining the above-described embodiments, it is possible to change the detected temperature. In addition, the temperature detection can be set by a program or can be performed at regular intervals. Temperature detection becomes possible. Further, when the enable signal 6 is invalid, it is possible to cut off the operating current of the generation circuit of the reference voltage 7, the generation circuit of the comparison voltage 8 and the comparator 9, thereby reducing the consumption current of the MCU due to the addition of the chip temperature detection circuit. The increase can be made only when the chip temperature is detected.

[0074]

According to the first aspect of the present invention, the first and second constant current circuits having no temperature dependency and the second constant current circuit having temperature dependency are provided as circuit elements. Temperature detection means for comparing the magnitude of a signal according to the current flowing through the constant current circuit and outputting a detection signal is provided as a circuit element, so that a transistor size suitable for the chip temperature can be selected. Using a constant current circuit having no dependency and a constant current circuit having temperature dependency, it is possible to obtain a microcomputer capable of appropriately detecting the chip temperature by utilizing the temperature dependency characteristics of these constant current circuits.

According to the second aspect, the first constant current circuit having no temperature dependency, the second constant current circuit having temperature dependency, and the current flowing through the first constant current circuit are determined according to the current flowing through the first constant current circuit. Reference voltage generation means for generating a reference voltage, and comparison voltage generation means for generating a comparison voltage in accordance with a current flowing through the second constant current circuit as circuit elements, and a voltage signal of the reference voltage and a comparison voltage signal Since the temperature detection means for comparing the magnitude and outputting the detection signal is provided as a circuit element, the transistor size can be selected according to the chip temperature.
A microcomputer capable of appropriately detecting the chip temperature based on a detection signal obtained by comparing the reference voltage and the comparison voltage can be obtained.

According to the third aspect of the present invention, the reference voltage generating means including a constant current circuit having no temperature dependency, a reference voltage generating circuit including a resistor and a MOS transistor switch, and generating a reference voltage; A comparison voltage generation means comprising a constant current circuit, a resistance and a MOS transistor switch, and a comparison voltage generation circuit for generating a comparison voltage is provided as a circuit element, and the magnitude of a voltage signal between the reference voltage and the comparison voltage is compared. A temperature detection means comprising a comparator for outputting a detection signal as a circuit element is provided as a circuit element, so that a temperature-independent constant current circuit, a resistor and a MOS transistor switch can be selected so as to select a transistor size suitable for a chip temperature. A reference voltage generated by reference voltage generating means including a reference voltage generating circuit configured by Appropriate chip temperature detection based on a detection signal obtained by comparing a comparison voltage generated by a comparison voltage generation means including a constant current circuit having a temperature dependency, a comparison voltage generation circuit including a resistor and a MOS transistor switch. The microcomputer which can be obtained can be obtained.

According to the fourth aspect, the first constant current circuit is constituted by a band gap type constant current circuit, and the second constant current circuit is constituted by a threshold difference type constant current circuit.
In order to be able to select the transistor size according to the chip temperature, a reference consisting of a constant current circuit consisting of a bandgap type constant current circuit having no temperature dependency and a reference voltage generating circuit consisting of a resistor and a MOS transistor switch A reference voltage generated by the voltage generating means, a constant current circuit including a threshold-difference-type constant current circuit having temperature dependency, and a comparison voltage generating means including a comparison voltage generating circuit including a resistor and a MOS transistor switch A microcomputer capable of appropriately detecting the chip temperature can be obtained by the detection signal based on the comparison with the comparison voltage generated by the microcomputer.

According to the fifth aspect, the detection signal is derived from the temperature detection means in accordance with the enable signal applied at a predetermined timing, so that the transistor size can be selected according to the chip temperature. As described above, it is possible to obtain a microcomputer that can appropriately detect the chip temperature while suppressing the current consumption by the detection signal controlled by the enable signal and derived by comparing the reference voltage and the comparison voltage.

According to the sixth aspect of the present invention, an operating current is generated in the MOS transistor switch and the comparator only when the enable signal input to the MOS transistor switch and the comparator is at the valid signal level. Since the detection signal is derived, it is controlled by whether the enable signal is at the valid signal level, and the detection of the chip temperature is suppressed by the detection signal derived by comparing the reference voltage with the comparison voltage while suppressing the current consumption. A microcomputer which can be appropriately performed can be obtained.

According to the seventh aspect, the temperature detecting means including the comparator holds the detection signal when the enable signal is at the effective signal level. Therefore, even when no operating current is generated in the MOS transistor switch and the comparator, Thus, it is possible to obtain a microcomputer capable of securing a detection signal by the temperature detecting means including the comparator and smoothly detecting the chip temperature.

According to the eighth aspect, the detection signal from the temperature detecting means can be changed by changing the reference voltage by the reference voltage generating means by switching on / off of the MOS transistor switch. The set detection temperature can be changed by adjusting the reference voltage by switching the conduction / non-conduction of the MOS transistor switch, and the transistor size suitable for the chip temperature can be selected. A microcomputer that can derive a chip temperature detection signal can be obtained.

According to the ninth aspect, a constant current circuit, a plurality of resistance elements for flowing the current of the constant current circuit, and a conduction control MOS transistor switch for controlling conduction / interruption of the current flowing through the resistance element And a bridge control MOS transistor switch for bridging the resistance element, wherein a reference voltage is generated by a voltage drop due to a current flowing through the resistance element, and a bridge control MOS transistor for bridging the resistance element. Since the reference voltage can be adjusted by controlling the conduction / non-conduction of the switch, the reference voltage is generated by the reference voltage generation means by switching the conduction / non-conduction of the conduction control MOS transistor switch and the bridge control MOS transistor. The detection signal from the temperature detection means can be changed by changing An appropriate chip according to the purpose of use so that the set detection temperature can be changed by adjusting the reference voltage by switching the conduction / non-conduction of the switch and the transistor size can be selected according to the chip temperature. A microcomputer that can derive a temperature detection signal can be obtained.

According to the tenth aspect, the detection signal from the temperature detection means can be changed by changing the comparison voltage by the comparison voltage generation means by switching on / off of the MOS transistor switch. The set detection temperature can be changed by adjusting the comparison voltage by switching the conduction / non-conduction of the MOS transistor switch, and the appropriate transistor size suitable for the chip temperature can be selected. A microcomputer that can derive a chip temperature detection signal can be obtained.

According to the eleventh aspect, a constant current circuit, a plurality of resistance elements for flowing the current of the constant current circuit, and a conduction control MOS transistor switch for controlling conduction / interruption of the current flowing through the resistance element And a bridge control MOS transistor switch for bridging the resistance element.
The comparison voltage is generated by a voltage drop due to a current flowing through the resistance element, and the comparison voltage can be adjusted by controlling conduction / non-conduction of a bridge control MOS transistor switch for bridging the resistance element. Therefore, the set detection temperature can be changed by adjusting the comparison voltage by switching the conduction / non-conduction of the MOS transistor switch, and the transistor size suitable for the chip temperature can be selected. A microcomputer that can derive an appropriate chip temperature detection signal can be obtained.

According to the twelfth aspect, the predetermined enable signal program is written, and the enable signal register for generating the enable signal according to the enable signal program is provided. The microcomputer which can appropriately detect the chip temperature can be obtained by the control by the enable signal generated by the enable signal register by the enable signal program so as to enable the microcomputer.

According to the thirteenth aspect, since the enable signal is written in the enable signal register by the operation program for operating each element of the microcomputer, the enable signal is written using the operation program of the microcomputer. By writing a signal, an enable signal can be generated reliably and easily, and a microcomputer capable of appropriately detecting a chip temperature by control using the enable signal can be obtained.

According to the fourteenth aspect, since the enable signal register is integrated as an integrated circuit element in the microcomputer chip, the chip temperature can be appropriately detected by controlling the enable signal in a structure integrated with the chip. A microcomputer can be obtained.

According to the fifteenth aspect, the enable signal is generated by writing the program to the monitoring timer register, so that the enable signal can be generated reliably and easily by the monitoring timer register. A microcomputer capable of appropriately detecting the chip temperature by control by the enable signal can be obtained.

According to the sixteenth aspect, the enable signal is generated by writing the program into the monitoring timer register integrated as an integrated circuit element in the chip of the microcomputer. A microcomputer capable of reliably and easily generating an enable signal and appropriately performing detection of a chip temperature by a control integrated with the chip by control of the enable signal can be obtained.

According to the seventeenth aspect, the operation program for operating each element of the microcomputer includes:
Since the enable signal is written to the monitor timer register, the enable signal can be generated reliably and easily by the monitor timer register written by the operation program for operating the microcomputer, A microcomputer capable of appropriately detecting the chip temperature by control using the enable signal and having a structure integrated with the chip can be obtained.

According to the eighteenth aspect, since the enable signal timer for generating the enable signal is provided,
The enable signal can be reliably generated by the timer, and a microcomputer capable of appropriately detecting the chip temperature by control by the enable signal can be obtained.

According to the nineteenth aspect, since the enable signal timer is integrated as an integrated circuit element in the microcomputer chip, the enable signal can be reliably generated by the timer, and the chip temperature can be controlled by the enable signal. A microcomputer capable of appropriately detecting the above by a configuration integrated with the chip can be obtained.

According to the twentieth aspect, the signal corresponding to the current flowing through the first constant current circuit having no temperature dependency provided on the microcomputer chip and the temperature dependency provided on the microcomputer chip are provided. Since the chip temperature is detected by comparing the magnitude of a signal corresponding to the current flowing through the second constant current circuit with the detection signal to obtain a detection signal, it is possible to select a transistor size suitable for the chip temperature. Thus, it is possible to obtain a chip temperature detecting method capable of appropriately detecting the chip temperature.

According to the twenty-first aspect, the reference voltage generated according to the current flowing through the first constant current circuit having no temperature dependence provided on the microcomputer chip and the reference voltage provided on the microcomputer chip are provided. The chip temperature is detected by comparing the magnitude of the voltage signal with the comparison voltage generated according to the current flowing through the second constant current circuit having the temperature dependency to obtain the detection signal. A chip temperature detection method capable of appropriately detecting a chip temperature based on a detection signal based on a comparison between a reference voltage and a comparison voltage so that a transistor size suitable for a temperature can be selected can be obtained.

According to the twenty-second aspect, since the detection signal is derived in accordance with the enable signal applied at a predetermined timing to detect the chip temperature, it is possible to select a transistor size suitable for the chip temperature. So that
With the control by the enable signal, it is possible to obtain a chip temperature detection method capable of appropriately detecting the chip temperature with low current consumption.

According to the twenty-third aspect, the detection signal is derived in accordance with the enable signal at the effective signal level to detect the chip temperature, and when the enable signal is not at the effective signal level, the detection signal is not derived. Since the detection signal when the enable signal is at the valid signal level is held, it is possible to obtain a chip temperature detection method capable of appropriately and smoothly detecting the chip temperature by control by the enable signal.

According to the twenty-fourth aspect, since the detection signal for detecting the chip temperature is changed by changing the signal value of the reference voltage, it is possible to select a transistor size suitable for the chip temperature. Thus, the set detection temperature can be changed by adjusting the reference voltage, and a chip temperature detection method capable of detecting an appropriate chip temperature according to the purpose of use can be obtained.

According to the twenty-fifth aspect, since the detection signal for detecting the chip temperature can be changed by changing the signal value of the comparison voltage, it is possible to select a transistor size suitable for the chip temperature. Thus, the set detection temperature can be changed by adjusting the comparison voltage, and a chip temperature detection method capable of detecting an appropriate chip temperature according to the purpose of use can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a chip temperature detection circuit according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a reference voltage generation circuit of FIG. 1;

FIG. 3 is a diagram showing a change in a reference voltage of the reference voltage generation circuit of FIG. 2;

FIG. 4 is a diagram illustrating a comparison voltage generation circuit of FIG. 1;

FIG. 5 is a diagram showing a change in a reference voltage of the comparison voltage generation circuit of FIG. 4;

FIG. 6 is a diagram showing an enable signal generation circuit according to an embodiment of the present invention.

FIG. 7 is a diagram showing an enable signal generation circuit according to another embodiment of the present invention.

FIG. 8 is a diagram showing an enable signal generation circuit according to another embodiment of the present invention.

[Explanation of symbols]

1 power supply, 2a, 2b constant current circuit, 3 resistor, 4M
OS transistor switch, 5 GND terminal, 6 enable signal, 7 reference voltage, 8 comparison voltage, temperature detection means including 9 comparators, 10 detection signal, 11 temperature determination register, 12 write signal, 13 monitoring timer register, 14 timer.

Claims (25)

[Claims] A first constant current circuit having no temperature dependence;
A temperature detecting means that includes a second constant current circuit having temperature dependency as a circuit element, and compares a magnitude of a signal corresponding to a current flowing through the first and second constant current circuits to output a detection signal. A microcomputer provided as a circuit element. 2. A first constant current circuit having no temperature dependency,
A second constant current circuit having a temperature dependency, reference voltage generating means for generating a reference voltage according to a current flowing through the first constant current circuit, and a reference voltage generating means generating a reference voltage according to a current flowing through the second constant current circuit And a comparison voltage generation means for generating a comparison voltage as a circuit element, and a temperature detection means for comparing a magnitude of a voltage signal of the reference voltage and the comparison voltage and outputting a detection signal is provided as a circuit element. Microcomputer. 3. A constant current circuit having no temperature dependence, a resistor and M
A reference voltage generation means including a reference voltage generation circuit configured to generate a reference voltage, configured by an OS transistor switch; a comparison voltage generation configured to include a constant current circuit having temperature dependency, a resistor, and a MOS transistor switch to generate a comparison voltage A comparison voltage generation means comprising a circuit as a circuit element, and a temperature detection means comprising a comparator for comparing a magnitude of a voltage signal of the reference voltage and the comparison voltage and outputting a detection signal is provided as a circuit element. Microcomputer. 4. The constant current circuit according to claim 1, wherein the first constant current circuit is constituted by a band gap type constant current circuit, and the second constant current circuit is constituted by a threshold difference type constant current circuit.
A microcomputer according to claim 3. 5. The microcomputer according to claim 1, wherein a detection signal is derived from the temperature detection means in accordance with an enable signal applied at a predetermined timing. 6. An operating current is generated in the MOS transistor switch and the comparator only when the enable signal input to the MOS transistor switch and the comparator is at a valid signal level, and a detection signal is derived from the temperature detecting means including the comparator. 6. The method according to claim 5, wherein
The microcomputer according to 1. 7. The microcomputer according to claim 6, wherein the temperature detection means comprising a comparator holds a detection signal when the enable signal is at a valid signal level. 8. The detection signal from the temperature detection means can be changed by changing the reference voltage by the reference voltage generation means by switching on / off of a MOS transistor switch. A microcomputer according to claim 7. 9. A constant current circuit, a plurality of resistance elements for passing the current of the constant current circuit, an energization control MOS transistor switch for controlling energization / cutoff of a current flowing through the resistance element, and Bridging bridge control MOS
A transistor switch for generating a reference voltage by a voltage drop caused by a current flowing through the resistance element, and controlling the conduction / non-conduction of a bridging control MOS transistor switch for bridging the resistance element. 9. The microcomputer according to claim 2, wherein the microcomputer can be adjusted. 10. The conduction of a MOS transistor switch /
10. The microcontroller according to claim 1, wherein a detection signal from the temperature detection means can be changed by changing a comparison voltage by the comparison voltage generation means by switching of non-conduction. Computer. 11. A constant current circuit, a plurality of resistance elements for flowing the current of the constant current circuit, an energization control MOS transistor switch for controlling energization / interruption of a current flowing through the resistance element, and MO for bridging control
An S transistor switch for generating a comparison voltage by a voltage drop caused by a current flowing through the resistance element, and controlling the conduction / non-conduction of a bridge control MOS transistor switch for bridging the resistance element. 11. The microcomputer according to claim 2, wherein the voltage can be adjusted. 12. The apparatus according to claim 5, wherein a predetermined enable signal program is written, and an enable signal register for generating an enable signal according to the enable signal program is provided. Microcomputer. 13. The microcomputer according to claim 12, wherein the enable signal is written in the enable signal register by an operation program for operating each element of the microcomputer. 14. The microcomputer according to claim 12, wherein the enable signal register is integrated as an integrated circuit element in a microcomputer chip. 15. The microcomputer according to claim 5, wherein an enable signal is generated by writing to the monitoring timer register by a program. 16. The microcomputer according to claim 5, wherein an enable signal is generated by writing a program into a monitoring timer register integrated as an integrated circuit element in the microcomputer chip. The microcomputer according to 1. 17. The microcomputer according to claim 15, wherein an operation program for operating each element of the microcomputer performs writing for generating an enable signal in the monitoring timer register. 18. An apparatus according to claim 5, further comprising an enable signal timer for generating an enable signal.
A microcomputer according to claim 7. 19. The microcomputer according to claim 18, wherein the enable signal timer is integrated as an integrated circuit element in a chip of the microcomputer. 20. A signal according to a current flowing through a first constant current circuit having no temperature dependency provided on a microcomputer chip, and a second constant having a temperature dependency provided on the microcomputer chip. A chip temperature detection method, wherein a chip temperature is detected by comparing a signal according to a current flowing through a current circuit with a magnitude and obtaining a detection signal. 21. A reference voltage generated according to a current flowing through a first constant current circuit having no temperature dependency provided on a microcomputer chip and having a temperature dependency provided on a microcomputer chip. A chip temperature detecting method for detecting a chip temperature by comparing a voltage signal with a comparison voltage generated according to a current flowing through a second constant current circuit to obtain a detection signal; . 22. The chip temperature detection method according to claim 20, wherein a detection signal is derived in accordance with an enable signal applied at a predetermined timing to detect a chip temperature. 23. A detection signal is derived in accordance with an enable signal at a valid signal level to detect a chip temperature. When the enable signal is not at a valid signal level, the detection signal is not derived and the enable signal is at a valid signal level. 23. The chip temperature detecting method according to claim 22, wherein a detection signal at the time of (1) is held. 24. The apparatus according to claim 21, wherein a detection signal for detecting a chip temperature is changed by changing a signal value of the reference voltage.
The chip temperature detecting method according to any one of the above. 25. The chip temperature detecting method according to claim 21, wherein a detection signal for detecting a chip temperature can be changed by changing a signal value of the comparison voltage.