Semiconductor device and temperature control method

Abstract

To provide a semiconductor device capable of appropriately controlling temperature, and a method for controlling its temperature. [Solution] The semiconductor device according to this disclosure includes a peripheral circuit, a CPU which includes a low-voltage transistor and controls the peripheral circuit, a temperature sensor which includes a high-voltage transistor with a higher voltage rating than the low-voltage transistor and outputs an analog signal indicating the measured temperature, an A / D converter which includes a high-voltage transistor and performs A / D conversion of the analog signal from the temperature sensor, and a control circuit which includes a high-voltage transistor and controls the peripheral circuit without going through the CPU when the measured temperature indicated by the digital signal from the A / D converter exceeds a threshold temperature.

Description

Technical Field

[0001] The present disclosure relates to a semiconductor device and a temperature control method thereof.

Background Art

[0002] Patent Document 1 discloses a preventive safety device for a semiconductor integrated circuit. This device includes a temperature detection device, a memory, an arithmetic device, and an output device. When the temperature detected by the temperature detection device is outside the standard range, the arithmetic device weights the count value and stores it in the memory. The output device outputs an alarm when the count value exceeds the set value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the storage device stores a temperature determination program. Then, the CPU (Central Processing Unit) executes the temperature determination program to detect the life of the semiconductor integrated circuit. However, if the CPU itself undergoes thermal runaway, the device may not operate normally.

[0005] Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.

Means for Solving the Problems

[0006] A semiconductor device according to an aspect of the present disclosure includes a peripheral circuit, a CPU, a temperature sensor, an A / D converter including the high-voltage transistor, a high-voltage transistor, and a control circuit that controls the peripheral circuit without passing through the CPU when the measured temperature exceeds a threshold temperature.

[0007] A temperature control method for a semiconductor device according to one aspect of the present disclosure comprises a peripheral circuit, a CPU, a temperature sensor, an A / D converter including the high-voltage transistor, and a control circuit including the high-voltage transistor, wherein the peripheral circuit is controlled without the CPU when the measured temperature exceeds a threshold temperature. [Effects of the Invention]

[0008] This disclosure provides a semiconductor device capable of appropriately controlling temperature, and a method for controlling its temperature. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing the configuration of a semiconductor device according to Embodiment 1. [Figure 2] This is a graph showing the change in measured temperature. [Figure 3] This graph shows the change in power supply voltage in control example 3. [Figure 4] This is a circuit diagram showing the configuration in control example 4. [Figure 5] This is a block diagram showing the configuration of a semiconductor device according to Embodiment 2. [Figure 6] This graph illustrates multiple threshold temperatures. [Figure 7] This is a block diagram showing the configuration of a semiconductor device according to Embodiment 3. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the drawings. Note that the drawings are simplified, and the technical scope of the embodiments should not be narrowly interpreted based on their depiction. Furthermore, the same elements are denoted by the same reference numerals, and redundant explanations are omitted.

[0011] Embodiment 1 The configuration of the semiconductor device according to this embodiment will be explained with reference to Figure 1. Figure 1 is a block diagram showing the configuration of the semiconductor device. The semiconductor device 100 includes a temperature sensor 10, an A / D converter 20, a control circuit 30, a CPU 40, and peripheral circuits 50. The semiconductor device 100 is, for example, a semiconductor chip such as a microcontroller.

[0012] The semiconductor device 100 is composed of two types of transistors with different voltage ratings. Specifically, the semiconductor device 100 has a high-voltage transistor with a high voltage rating and a low-voltage transistor with a low voltage rating. The high-voltage transistor has a higher voltage rating than the low-voltage transistor. For example, the operating voltage of the low-voltage transistor is 0.9 to 1.5V, while the operating voltage of the high-voltage transistor is 3.3 to 5.0V.

[0013] Furthermore, low-voltage transistors have higher operating frequencies than high-voltage transistors. For example, the operating frequency of low-voltage transistors is 100MHz to 1000MHz, while that of high-voltage transistors is around 50MHz. Low-voltage transistors tend to have a significantly increased leakage current depending on the operating temperature. On the other hand, the increase in leakage current in response to operation is more gradual. For example, the leakage current of a low-voltage transistor is around 1A, while that of a high-voltage transistor is 10mA. Therefore, low-voltage transistors are more prone to thermal runaway than high-voltage transistors. Specifically, when a voltage higher than the above operating voltage is applied to the transistor, a leakage current is generated.

[0014] The CPU 40 is composed of low-voltage transistors. In other words, the CPU 40 has low-voltage transistors with a high operating frequency. The temperature sensor 10, A / D converter 20, and control circuit 30 have high-voltage transistors. The control circuit 30 has high-voltage transistors that are less prone to thermal runaway.

[0015] The temperature sensor 10 measures the internal temperature of the semiconductor device 100. The temperature sensor 10 is built into the semiconductor chip that becomes the semiconductor device 100. And the temperature sensor 10 measures the internal temperature within the chip. The temperature sensor 10 outputs an analog signal indicating the measured temperature to the A / D converter 20. That is, the analog signal output from the temperature sensor 10 has a voltage corresponding to the measured temperature.

[0016] The A / D converter 20 performs AD (Analog to Digital) conversion on the analog signal. Therefore, the signal output from the A / D converter 20 becomes a digital signal indicating the measured temperature.

[0017] The peripheral circuit 50 is an integrated circuit such as an IP (Intellectual Property) core having various functions. For example, the peripheral circuit 50 has a power supply circuit or a memory circuit (memory). The power supply circuit functions as an internal power supply of the semiconductor device 100 and supplies a power supply voltage. The memory circuit is a SRAM (Static Random Access Memory), MRAM (Magnetoresistive Random Access Memory), flash memory, etc.

[0018] Of course, the peripheral circuit 50 is not limited to these circuits. For example, the peripheral circuit 50 is a communication circuit, a bus interface (IF) circuit, a timer circuit, an input / output circuit, a sensor circuit, a clock circuit, a D / A converter, a PLL circuit, etc. Also, the peripheral circuit 50 may be an image processing circuit, an audio processing circuit, a decoding circuit, an encoding circuit, etc. The peripheral circuit 50 may have a plurality of IP cores.

[0019] The CPU 40 controls the temperature sensor 10, the ADC 20, the peripheral circuit 50, etc. For example, the CPU 40 executes a program stored in a memory or the like. For example, the CPU 40 executes a predetermined arithmetic processing on data input from the outside or the peripheral circuit 50. And the CPU 40 outputs the result of the arithmetic processing to the outside or the peripheral circuit 50.

[0020] The control circuit 30 is a circuit for performing temperature control. That is, the temperature of the semiconductor device can be appropriately controlled by the control of the control circuit 30. A digital signal from the A / D converter 20 is input to the control circuit 30. As described above, the digital signal from the A / D converter 20 is a signal indicating the measured temperature by the temperature sensor 10. The control circuit 30 compares the measured temperature with a threshold temperature. When the measured temperature exceeds the threshold temperature, the control circuit 30 performs control to lower the temperature.

[0021] Specifically, when the measured temperature exceeds the threshold temperature, the control circuit 30 controls the peripheral circuit 50 without going through the CPU 40. By doing so, the temperature of the semiconductor device 100 can be appropriately controlled, and thermal runaway can be avoided. When the measured temperature exceeds the threshold temperature, the semiconductor device 100 performs a safety operation to lower the temperature. Hereinafter, several control examples by the control circuit 30 will be described. In the following control examples 1 to 4, the control circuit 30 performs different controls. That is, in the following control examples 1 to 4, the semiconductor device 100 performs different safety operations.

[0022] (Control Example 1) In control example 1, the control circuit 30 controls the power supply circuit included in the peripheral circuit 50. The power supply circuit supplies the power supply voltage of the semiconductor device 100. When the measured temperature exceeds the threshold temperature, the control circuit 30 cuts off the supply of the power supply voltage to some circuits and blocks.

[0023] For example, assume that the semiconductor device 100 is divided into a plurality of blocks (power domains). The power supply circuit can control the power on / off for each block. When the measured temperature exceeds the threshold temperature, the control circuit 30 outputs a control signal for controlling the power supply to the power supply circuit. The power supply circuit cuts off the power supply to one or more power domains based on the control signal.

[0024] Figure 2 is a graph illustrating the control by the control circuit 30. In Figure 2, the horizontal axis represents time, and the vertical axis represents the temperature measured by the temperature sensor 10. Assume that the measured temperature is rising over time (A in Figure 2). The control circuit 30 compares the measured temperature with a threshold temperature. At the moment the measured temperature reaches the threshold temperature (B in Figure 2), the control circuit 30 stops supplying power. This stops the operation of at least some of the peripheral circuits 50, thereby suppressing heat generation due to circuit operation. Consequently, the measured temperature gradually decreases (C in Figure 2). In this way, the internal temperature of the chip can be lowered, allowing the semiconductor device 100 to transition to a safe state. Therefore, thermal runaway of the CPU 40 and other components can be avoided.

[0025] As described above, the CPU 40 is composed of low-voltage transistors. This results in high leakage current in the CPU 40, potentially causing thermal runaway. On the other hand, the temperature sensor 10, A / D converter 20, and CPU 40 are composed of high-voltage transistors. Therefore, the temperature sensor 10, A / D converter 20, and control circuit 30 have low leakage current. When the measured temperature exceeds the threshold temperature, the control circuit 30 controls the peripheral circuit 50 without going through the CPU 40.

[0026] In this way, the temperature of the semiconductor device 100 can be appropriately controlled, thus preventing thermal runaway. Specifically, the control circuit 30 controls the power supply to peripheral circuits 50, etc., based on the measured temperature. As a result, some of the operation of peripheral circuits 50 is stopped. This suppresses the heat generated by the operation of peripheral circuits 50. Therefore, the internal temperature within the chip can be lowered before the CPU 40 rises to a temperature at which it would experience thermal runaway. Furthermore, since temperature rise can be prevented, unexpected device damage can be avoided.

[0027] Furthermore, the power supply domains that are shut off according to the measured temperature can be changed in stages. Multiple threshold temperatures can be set, and a power supply domain to be shut off for each threshold temperature can be configured. For example, if the first threshold temperature is exceeded, the power supply to the first power supply domain is shut off. Then, if the second threshold temperature is exceeded, the power supply to the second power supply domain is shut off. In this way, the blocks that shut off the power supply can be expanded in stages. As the measured temperature rises, power consumption is suppressed. Therefore, the temperature rise can be effectively suppressed.

[0028] (Control example 2) In control example 2, the control circuit 30 switches the operating mode of the semiconductor device 100. For example, the semiconductor device 100 can operate in a normal operating mode and a low-power mode. In the normal operating mode, the peripheral circuits 50 of the semiconductor device 100 perform normal operations. In the low-power mode, at least some of the circuits of the peripheral circuits 50 operate with lower power consumption than in the normal operating mode. When the measured temperature exceeds the threshold temperature, the control circuit 30 switches the peripheral circuits 50 to a low-power mode, which consumes less power than the normal operating mode. In other words, the control circuit 30 transitions the semiconductor device 100 from the normal operating mode to the low-power mode.

[0029] For example, in low-power mode, the functions of some circuits are stopped. Alternatively, in low-power mode, the operating speed of some circuits is slowed down. In this way, heat generation can be suppressed when the measured temperature exceeds the threshold temperature (B in Figure 2). The measured temperature gradually decreases (C in Figure 2). Because the internal temperature of the chip can be lowered, the semiconductor device 100 can be transitioned to a safe state. Therefore, thermal runaway of the CPU 40, etc., can be avoided. Furthermore, because temperature rise can be prevented, unexpected device damage can be avoided.

[0030] Furthermore, the mode may be changed in stages according to the measured temperature. Multiple threshold temperatures may be prepared, and the mode set for each threshold temperature may be switched. Power consumption is suppressed as the measured temperature rises. Therefore, temperature rise can be effectively suppressed.

[0031] (Control example 3) Control Example 3 will be explained using Figure 3. Figure 3 is a graph showing the change in power supply voltage. In Control Example 3, the control circuit 30 controls the power supply voltage supplied by the power supply circuit to decrease. For example, as shown in Figure 3, the semiconductor device 100 is assumed to have an operating range set for the power supply voltage within the chip. When the measured temperature is below the threshold temperature, the semiconductor device 100 is assumed to be operating at a voltage V1 within the operating range. When the measured temperature exceeds the threshold temperature, the semiconductor device 100 operates at a voltage V2 within the operating range.

[0032] Voltage V2 is lower than voltage V1. Voltage V2 is close to the lower limit of the operating range. In other words, the control circuit 30 controls the power supply circuit to lower the power supply voltage supplied by the power supply circuit. By doing so, heat generation in the semiconductor device 100 can be suppressed. The control circuit 30 can properly control the temperature and avoid thermal runaway of the CPU 40. Furthermore, since it can prevent temperature rise, unexpected device damage can be avoided.

[0033] Alternatively, the power supply voltage may be gradually reduced according to the measured temperature. For example, the control circuit 30 can store multiple threshold temperatures and set the power supply voltage to be reduced for each threshold temperature. In this way, as the measured temperature rises, the power supply circuit will reduce the power supply voltage. Therefore, the temperature rise can be effectively suppressed.

[0034] (Control example 4) In control example 4, the control circuit 30 restricts the CPU 40's access to the peripheral circuits 50. Control example 4 will be explained using Figure 4. Figure 4 is a schematic diagram showing an example of a circuit configuration. In Figure 4, the peripheral circuits 50 include MRAM 51, flash memory 52, SRAM 53, and peripheral IP core 54.

[0035] When the measured temperature is below the threshold temperature, the CPU 40 can access the MRAM 51, flash memory 52, SRAM 53, and peripheral IP core 54. An access restriction circuit 301 is provided between the CPU 40 and the peripheral circuit 50. The access restriction circuit 301 restricts the CPU 40's access to the peripheral circuit 50.

[0036] For example, when the access restriction circuit 301 restricts access, the CPU 40 cannot write data to the MRAM 51, flash memory 52, or SRAM 53. Alternatively, when the access restriction circuit 301 restricts access, the CPU 40 cannot read data from the MRAM 51, flash memory 52, or SRAM 53. In other words, the access restriction circuit 301 restricts the CPU 40 from writing and reading data.

[0037] The control circuit 30 controls the access restriction circuit 301 based on the temperature measured by the temperature sensor 10. When the measured temperature exceeds the threshold temperature, the control circuit 30 outputs a control signal to the access restriction circuit 301. This causes the control circuit 30 to control the access restriction circuit 301 so that the CPU 40's access to the peripheral circuit 50 is restricted. In Figure 4, the access restriction circuit 301 has a logic circuit such as an AND gate. When the measured temperature exceeds the threshold temperature, the control circuit 30 outputs an L signal to the access restriction circuit 301. This restricts the CPU 40's access to the peripheral circuit 50.

[0038] Furthermore, if the measured temperature is below the threshold, the control circuit 30 controls the access restriction circuit 301 so that it does not restrict access. This allows the CPU 40 to perform data writing and reading operations.

[0039] This method suppresses heat generation caused by data reading and writing. Furthermore, since data writing and reading are restricted at high temperatures, chip malfunctions can be prevented. In addition, chip damage can be prevented.

[0040] Furthermore, the access restriction by the access restriction circuit 301 may be applied to peripheral IP cores 54 other than the MRAM 51, flash memory 52, and SRAM 53. When the access restriction circuit 301 restricts access, the CPU 40 is unable to control the peripheral IP cores 54. Since the operation of the peripheral IP cores 54 stops, heat generation can be suppressed. In addition, malfunctions at high temperatures can be suppressed, and chip damage can be avoided. Moreover, if there are IP cores of high-speed components such as DC-DC converters, circuit malfunctions can be prevented.

[0041] Furthermore, the control circuit 30 may change the access restrictions in stages according to the measured temperature. The control circuit 30 stores multiple threshold temperatures and changes the IP cores to which access is restricted for each threshold temperature. For example, if the first threshold temperature is exceeded, the control circuit 30 restricts access only to the MRAM 51. Then, if the second threshold temperature is exceeded, the control circuit 30 restricts access to both the MRAM 51 and the flash memory 52. ​​In this way, the IP cores to which access restrictions are imposed may be expanded in stages.

[0042] Embodiment 2 The semiconductor device according to Embodiment 2 will be described with reference to Figure 5. Figure 5 is a block diagram showing the circuit configuration of the semiconductor device 100. The semiconductor device 100 includes a temperature sensor 10, an A / D converter 20, a control circuit 30, and a flash memory 60. The semiconductor device 100 also includes a power supply circuit 510 and a memory 520. Note that the CPU 40 is omitted in Figure 5.

[0043] In the following description, configurations and controls common to Embodiment 1 will be omitted as appropriate. For example, the temperature sensor 10, A / D converter 20, control circuit 30, and CPU 40 have the same functions as in Embodiment 1. Also, the power supply circuit 510 and memory 520 correspond to the peripheral circuit 50 shown in Embodiment 1.

[0044] The control circuit 30 includes a chip temperature information register 31, a comparator 32, a safety operation selection circuit 33, a low power consumption mode circuit 34, a temperature determination level information register 35, and a safety operation selection register 36. The power supply circuit 510 includes a power cut-off circuit 511 and a power supply voltage changing circuit 512. The power cut-off circuit 511 stops the power supply to some circuits, as shown in control example 1. The power supply voltage changing circuit 512 changes the power supply voltage, as shown in control example 3.

[0045] When the temperature sensor 10 measures the internal chip temperature, it outputs an analog signal indicating the measured temperature to the A / D converter 20. The A / D converter 20 performs AD conversion on the analog signal and outputs it to the chip temperature information register 31. The signal output by the A / D converter 20 is called the chip temperature information. The chip temperature information is data indicating the temperature measured by the temperature sensor 10. The chip temperature information register 31 stores the measured temperature.

[0046] The flash memory 60 stores temperature judgment level information and safety operation information. The temperature judgment level information is information about the threshold temperature. In other words, the flash memory stores data indicating the threshold temperature.

[0047] Safety operation information is information that indicates a safety operation to be performed when the temperature rises. For example, the operations of control examples 1 to 4 shown in Embodiment 1 are registered as safety operations. When the measured temperature exceeds a threshold, the control circuit 30 executes one of control examples 1 to 4 based on the data indicated by the safety operation information. The flash memory 60 stores data indicating a safety operation to be performed when the temperature rises as safety operation information.

[0048] The control circuit 30 reads the temperature judgment level information and safety operation information stored in the flash memory 60. For example, when the semiconductor device 100 is started up, the control circuit 30 reads the temperature judgment level information and safety operation information from the flash memory 60. The temperature judgment level information register 35 stores the temperature judgment level information. The temperature judgment level information register 35 may be updatable. The safety operation selection register 36 stores the safety operation information. The value of the safety operation selection register 36 may be updatable.

[0049] The comparator 32 compares the chip temperature information with the temperature judgment level information. In other words, the comparator 32 determines whether the measured temperature exceeds the threshold temperature. The comparator 32 outputs the comparison result to the safety operation selection circuit 33.

[0050] The safety operation selection circuit 33 selects a safety operation by referring to the value of the safety operation selection register 36. In other words, the safety operation selection circuit 33 selects a safety operation based on safety operation information. The safety operation selection circuit 33 controls the system to execute the selected safety operation when the measured temperature exceeds the threshold temperature.

[0051] As shown in Control Example 1, let's assume that stopping the power supply is the safe operation. In this case, the safe operation selection circuit 33 outputs a control signal to the power cut-off circuit 511. As a result, the power cut-off circuit 511 stops supplying power from the power supply circuit 510 to some of the circuits. In this way, when the measured temperature exceeds the threshold temperature, the control circuit 30 stops the power supply without going through the CPU 40.

[0052] As shown in Control Example 2, let's assume that switching to low-power mode is a safe operation. In this case, the safe operation selection circuit 33 outputs a control signal to the low-power mode circuit 34. As a result, the low-power mode circuit 34 switches the operating mode of the semiconductor device 100 from normal operation mode to low-power mode. In this way, when the measured temperature exceeds the threshold temperature, the control circuit 30 switches the mode without going through the CPU 40.

[0053] As shown in Control Example 3, assume that the power supply voltage change is set to safe operation. In this case, the safe operation selection circuit 33 outputs a control signal to the power supply voltage change circuit 512. As a result, the power supply voltage change circuit 512 lowers the power supply voltage of the semiconductor device 100. In this way, when the measured temperature exceeds the threshold temperature, the control circuit 30 lowers the power supply voltage without going through the CPU 40.

[0054] As shown in Control Example 4, assume that access restriction to peripheral circuits is set to safe operation. In this case, the safe operation selection circuit 33 outputs a control signal to the access restriction circuit 521. As a result, the access restriction circuit 521 restricts access from the CPU 40 to the memory 520, etc. In this way, when the measured temperature exceeds the threshold temperature, the control circuit 30 restricts access without going through the CPU 40. The memory 520 can be SRAM, MRAM, flash memory, etc.

[0055] The flash memory 60 stores temperature judgment level information and safety operation information. Therefore, the threshold temperature and safety operation are variable. For example, when a user updates the settings in the flash memory 60, the control circuit 30 updates the threshold temperature and safety operation. The semiconductor device 100 can then perform appropriate safety operations. For example, a user can change the safety operation according to the operating environment of the semiconductor device 100. In other words, by changing the threshold temperature and safety operation, the user can more effectively suppress device damage due to temperature rise.

[0056] Specifically, the user changes the temperature judgment level information indicating the threshold temperature by rewriting the value in the flash memory 60. The user can set an appropriate threshold temperature for the semiconductor device 100. Alternatively, the user can change the safety operation by rewriting the value in the flash memory 60. Therefore, the user can set an effective safety operation for the semiconductor device 100. Of course, non-volatile memory other than the flash memory 60 may also store the setting value. The user just needs to rewrite the setting value in the memory.

[0057] In this way, the user can set the threshold temperature and safety actions, allowing for appropriate control of the semiconductor device 100's temperature. Furthermore, the value in the flash memory 60 is transferred to the register when the semiconductor device 100 is powered on. Therefore, the user can update the threshold temperature and safety actions simply by rewriting the value in the flash memory 60 to match their operating environment. Note that the safety actions performed are not limited to one; there may be two or more. For example, a power supply voltage reduction and access restriction to peripheral circuits may occur simultaneously. The safety action selection register 36 stores information on multiple safety actions.

[0058] Multiple threshold temperatures may be set to perform safety operations in stages. As shown in Figure 6, the temperature judgment level information register 35 stores four threshold temperatures TH1, TH2, TH3, and TH4. Threshold temperature TH1 is the lowest temperature, and threshold temperature TH4 is the highest temperature. Threshold temperature TH2 is between threshold temperatures TH3 and TH1. The flash memory 60 also stores the four threshold temperatures TH1 to TH4 as temperature judgment level information. The safety operation selection register 36 stores four safety operation information items. Each of the threshold temperatures TH1 to TH4 is associated with a safety operation information item.

[0059] For example, if the measured temperature exceeds the threshold temperature TH1, the control circuit 30 restricts access to the peripheral circuit 50. If the measured temperature exceeds the threshold temperature TH2, the control circuit 30 reduces the power supply voltage. If the measured temperature exceeds the threshold temperature TH3, the control circuit 30 switches to a low-power mode. If the measured temperature exceeds the threshold temperature TH4, the control circuit 30 shuts off the power supply voltage. The higher the threshold temperature, the more effective the safety operation set.

[0060] The flash memory 60 stores multiple threshold temperatures and associated safety actions. This allows the safety action to be changed according to the threshold temperature. This effectively lowers the temperature of the semiconductor device 100. For example, if some safety actions do not lower the temperature, a more effective safety action is executed. Of course, multiple safety actions may be set for a single threshold temperature.

[0061] Embodiment 3 The semiconductor device 100 according to this embodiment will be described with reference to Figure 7. Figure 7 is a block diagram showing the circuit configuration of the semiconductor device 100. In this embodiment, an interrupt control circuit 70 is added to the configuration of Embodiment 2. The interrupt control circuit 70 includes an interrupt circuit 71. In addition, the control circuit 30 has an interrupt request flag 38. The basic configuration and operation of the semiconductor device 100 are the same as in Embodiments 1 and 2, so their explanation will be omitted as appropriate.

[0062] The comparator 32 sets an interrupt request flag 38 if the measured temperature is higher than the threshold temperature. When the interrupt request flag 38 is set, it notifies the interrupt control circuit 70 that the measured temperature has exceeded the threshold temperature. The interrupt control circuit 70 has an interrupt circuit 71. When the interrupt request flag 38 is set, the interrupt circuit 71 makes an interrupt request to the CPU 40. In this way, the control circuit 30 interrupts the processing of the CPU 40 and performs safe operation. Therefore, the control circuit 30 can quickly perform safe operation. For example, it can perform access restriction before the CPU 40 performs data writing or reading operations to the memory 520.

[0063] This helps avoid unexpected device damage and suppresses chip malfunctions.

[0064] Although the present invention has been specifically described above based on embodiments, it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways without departing from its essence. [Explanation of Symbols]

[0065] 100 Semiconductor Devices 10 Temperature Sensor 20 A / D converters 30 Control circuits 31 Chip temperature information register 32 Comparator 33 Safety Operation Selection Circuit 34 Low-power mode circuit 35 Temperature Judgment Level Information Register 36 Safe Operation Selection Register 301 Access Restriction Circuit 40 CPU 50 Peripheral Circuits 51 MRAM 52 flash memory 53 SRAM 54 Peripheral IP Cores 60 Flash Memory 510 Power supply circuit 511 Power cutoff circuit 512 Power supply voltage change circuit 520 memory 521 Access Restriction Circuit

Claims

1. Peripheral circuits and, A CPU (Central Processing Unit) that includes a low-voltage transistor and controls the peripheral circuitry, A temperature sensor that includes a high-voltage transistor with a higher voltage rating than the low-voltage transistor and outputs an analog signal indicating the measured temperature, An A / D converter including the high-voltage transistor that performs A / D conversion on the analog signal from the temperature sensor, A semiconductor device comprising the high-voltage transistor and a control circuit that controls the peripheral circuit without going through the CPU when the measured temperature indicated by the digital signal from the A / D converter exceeds a threshold temperature.

2. The aforementioned peripheral circuit includes a power supply circuit that provides power, The semiconductor device according to claim 1, wherein the control circuit cuts off the power supply to the power circuit when the measured temperature exceeds a threshold temperature.

3. The semiconductor device according to claim 1, wherein, when the measured temperature exceeds a threshold temperature, the control circuit switches the peripheral circuit to a low-power mode that consumes less power than the normal operating mode.

4. The aforementioned peripheral circuit includes a power supply circuit that provides power, The semiconductor device according to claim 1, wherein, when the measured temperature exceeds a threshold temperature, the control circuit controls the power supply voltage supplied by the power supply circuit to be reduced.

5. The semiconductor device according to claim 1, wherein if the measured temperature exceeds a threshold temperature, the control circuit restricts access to the peripheral circuit.

6. The control circuit includes a register for storing set values, The semiconductor device according to claim 1, wherein the threshold temperature is changed by updating the setting value of the register.

7. The system further includes a non-volatile memory for storing the aforementioned setting values. The semiconductor device according to claim 6, wherein when the semiconductor device is started up, the value stored in the non-volatile memory is transferred to the register.

8. The aforementioned register stores multiple setting values, The semiconductor device according to claim 6, wherein the control circuit performs different control depending on the set value.

9. Peripheral circuits and, A CPU (Central Processing Unit) controls the aforementioned peripheral circuits, A temperature sensor that outputs an analog signal indicating the measured temperature, An A / D converter that performs A / D conversion on the analog signal from the temperature sensor, A temperature control method for a semiconductor device, comprising a temperature sensor, an A / D converter, and a control circuit including a low-voltage transistor having a lower voltage rating than the high-voltage transistor included in the CPU, The control circuit, The measured temperature, indicated by the digital signal from the A / D converter, is compared with the threshold temperature. A temperature control method for a semiconductor device that controls the peripheral circuit without going through the CPU when the measured temperature exceeds the threshold temperature.

10. The aforementioned peripheral circuit includes a power supply circuit that provides power, The temperature control method for a semiconductor device according to claim 9, wherein the control circuit cuts off the power supply to the power circuit when the measured temperature exceeds a threshold temperature.

11. The temperature control method for a semiconductor device according to claim 9, wherein when the measured temperature exceeds a threshold temperature, the control circuit switches the peripheral circuit to a low-power mode that consumes less power than the normal operating mode.

12. The aforementioned peripheral circuit includes a power supply circuit that provides power, The temperature control method for a semiconductor device according to claim 9, wherein, when the measured temperature exceeds a threshold temperature, the control circuit controls the power supply voltage supplied by the power supply circuit to be reduced.

13. The temperature control method for a semiconductor device according to claim 9, wherein if the measured temperature exceeds a threshold temperature, the control circuit restricts access to the peripheral circuit.

14. The control circuit includes a register for storing set values, The temperature control method for a semiconductor device according to claim 9, wherein the threshold temperature is changed by updating the setting value of the register.

15. The system further includes a non-volatile memory for storing the aforementioned setting values. The method for controlling the temperature of a semiconductor device according to claim 14, wherein when the semiconductor device is started up, the value stored in the non-volatile memory is transferred to the register.

16. The aforementioned register stores multiple setting values, The method for controlling the temperature of a semiconductor device according to claim 15, wherein the control circuit performs different control depending on the set value.

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