Temperature sensor integral with microprocessor and methods of using same
First Claim
1. A temperature sensor, comprising:
- a bandgap reference circuit for providing a temperature-independent reference voltage;
a biasing circuit that mirrors a current in the bandgap reference circuit for providing a temperature-dependent biasing voltage; and
an amplifier responsive to the reference voltage and the biasing voltage for providing a temperature-dependent output voltage.
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Accused Products
Abstract
A temperature sensor includes a bandgap reference circuit for providing a temperature-independent reference voltage, a biasing circuit that mirrors a current in the bandgap reference circuit for providing a temperature-dependent biasing voltage, and an amplifier responsive to the reference voltage and the biasing voltage for providing a temperature-dependent output voltage. Preferably, the temperature sensor is integral with a microprocessor and implemented in CMOS technology. The temperature sensor can be used, for instance, to reduce the clock speed of the microprocessor when the microprocessor temperature exceeds a predetermined temperature, or to store temperature-indicating data in non-volatile memory of the microprocessor to provide a thermal history of the microprocessor.
212 Citations
52 Claims
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1. A temperature sensor, comprising:
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a bandgap reference circuit for providing a temperature-independent reference voltage; a biasing circuit that mirrors a current in the bandgap reference circuit for providing a temperature-dependent biasing voltage; and an amplifier responsive to the reference voltage and the biasing voltage for providing a temperature-dependent output voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A temperature sensor, comprising:
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a bandgap reference circuit for providing a temperature-independent reference voltage; a biasing circuit that mirrors a current in the bandgap reference circuit for providing a temperature-dependent biasing voltage that is proportional to absolute temperature; a first operational amplifier responsive to the reference voltage for providing a temperature-independent buffered reference voltage; and an amplifier responsive to the buffered reference voltage and the biasing voltage for providing a temperature-dependent output voltage that is proportional to absolute temperature. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A temperature sensor, comprising:
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a bandgap reference circuit, including; first, second and third field effect transistors with control terminals coupled to a first node and output terminals coupled to a first power supply terminal, wherein the second field effect transistor includes another output terminal coupled to the first node; fourth and fifth field effect transistors with control terminals coupled to a second node, wherein the fourth field effect transistor includes an output terminal coupled to the second node; first, second and third diode-connected bipolar transistors with control terminals and output terminals coupled to a second power supply terminal; and first and second resistors, wherein the first resistor is coupled between output terminals of the fifth field effect transistor and the second diode-connected bipolar transistor, and the second resistor is coupled between output terminals of the third field effect transistor and the third diode-connected bipolar transistor;
whereina first current path between the first and second power supply terminals includes the first and fourth field effect transistors and the first diode-connected bipolar transistor; a second current path between the first and second power supply terminals includes the second and fifth field effect transistors and the first resistor and the second diode-connected bipolar transistor; a third current path between the first and second power supply terminals includes the third field effect transistor and the second resistor and the third diode-connected bipolar transistor; and a temperature-independent reference voltage is provided at a third node in the third current path between the third field effect transistor and the second resistor; a biasing circuit, including; a sixth field effect transistor with a control terminal coupled to the first node and an output terminal coupled to the first power supply terminal; and a third resistor coupled between another output terminal of the sixth field effect transistor and the second power supply terminal;
whereina fourth current path between the first and second power supply terminals includes the sixth field effect transistor and the third resistor; and a temperature-dependent biasing voltage is provided at a fourth node in the fourth current path between the sixth field effect transistor and the third resistor; a buffering stage with an input terminal coupled to the third node and an output terminal coupled to a fifth node; an amplifying stage, including; an operational amplifier with a non-inverting input terminal coupled to the fourth node, an inverting input terminal, and an output terminal; a fourth resistor coupled to the inverting input terminal and the fifth node; and a fifth resistor coupled to the inverting input terminal and the output terminal of the operational amplifier;
whereina temperature-dependent output voltage is provided at the output terminal of the operational amplifier. - View Dependent Claims (22, 23, 24, 25)
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26. A temperature sensor, comprising:
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a bandgap reference circuit, including; first, second and third P-channel transistors with gates coupled to a first node and sources coupled to a power supply terminal, wherein the second P-channel transistor includes a drain coupled to the first node; first and second N-channel transistors with gates coupled to a second node, wherein the first N-channel transistor includes a drain coupled to the second node; first, second and third diode-connected PNP transistors with bases and collectors coupled to ground; and first and second resistors, wherein the first resistor is between a source of the second N-channel transistor and an emitter of the second PNP transistor, and the second resistor is between a source of the third P-channel transistor and an emitter of the third PNP transistor;
whereina first current path between the power supply terminal and ground includes the first P-channel transistor and the first N-channel transistor and the first PNP transistor; a second current path between the power supply terminal and ground includes the second P-channel transistor and the second N-channel transistor and the first resistor and the second PNP transistor; a third current path between the power supply terminal and ground includes the third P-channel transistor and the second resistor and the third PNP transistor; and a temperature-independent reference voltage is provided at a third node in the third current path between the third P-channel transistor and the second resistor; a biasing circuit, including; a fourth P-channel transistor with a gate coupled to the first node and a source coupled to the power supply terminal; and a third resistor coupled between a drain of the fourth P-channel transistor and ground;
whereina fourth current path between the power supply terminal and ground includes the fourth P-channel transistor and the third resistor; and a temperature-dependent biasing voltage is provided at a fourth node in the fourth current path between the fourth P-channel transistor and the third resistor; a first operational amplifier with a non-inverting input terminal coupled to the third node; and a second operational amplifier with a non-inverting input terminal coupled to the fourth node, wherein a fourth resistor is coupled between an inverting input terminal and an output terminal of the second operational amplifier, a fifth resistor is coupled between an output terminal of the first operational amplifier and the inverting input terminal of the second operational amplifier, and the output terminal of the second operational amplifier provides a temperature-dependent output voltage. - View Dependent Claims (27, 28, 29)
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30. A temperature sensor integral with a microprocessor in a single integrated circuit chip, wherein the temperature sensor comprises:
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a bandgap reference circuit for providing a temperature-independent reference voltage, a biasing circuit that mirrors a current in the bandgap reference circuit for providing a temperature-dependent biasing voltage, and an amplifier responsive to the reference voltage and the biasing voltage for providing an output signal.
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31. A method of sensing temperature, comprising:
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providing a temperature-independent reference voltage using a bandgap reference circuit; providing a temperature-dependent biasing voltage using a biasing circuit that mirrors a current in the bandgap reference circuit; and providing a temperature-dependent output voltage using an amplifier responsive to the reference voltage and the biasing voltage. - View Dependent Claims (32, 33, 34, 35)
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36. A method of using a temperature sensor integral with a microprocessor, comprising:
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operating the microprocessor at an operating temperature; using the temperature sensor to generate a temperature-dependent output signal indicative of the operating temperature, where the temperature sensor includes a bandgap reference circuit for providing a temperature-independent reference voltage, a biasing circuit that mirrors a current in the bandgap reference circuit for providing a temperature-dependent biasing voltage, and an amplifier responsive to the reference voltage and the biasing voltage for providing the output signal; and issuing a warning signal to a user in response to the output signal indicating that the operating temperature exceeds a predetermined temperature. - View Dependent Claims (37, 38, 39, 40)
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41. A method of using a temperature sensor integral with a microprocessor, comprising:
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operating the microprocessor at an operating temperature; using the temperature sensor to generate a temperature-dependent output signal indicative of the operating temperature; and reducing a clock speed of the microprocessor in response to the output signal indicating that the operating temperature exceeds a predetermined temperature. - View Dependent Claims (42, 43, 44, 45, 46)
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47. A method of using a temperature sensor integral with a microprocessor, comprising:
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operating the microprocessor at an operating temperature; using the temperature sensor to generate a temperature-dependent output signal indicative of the operating temperature, where the temperature sensor includes a bandgap reference circuit for providing a temperature-independent reference voltage, a biasing circuit that mirrors a current in the bandgap reference circuit for providing a temperature-dependent biasing voltage, and an amplifier responsive to the reference voltage and the biasing voltage for providing the output signal; providing digital temperature-indicating data in response to the output signal; and storing the temperature-indicating data in non-volatile memory of the microprocessor. - View Dependent Claims (48, 49, 50, 51, 52)
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Specification