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A combined low-voltage, low-power band-gap reference and temperature sensor circuit is provided for providing a band-gap reference parameter and for sensing the temperature of a chip, such as an eDRAM memory unit or CPU chip, using the band-gap reference parameter. The combined sensor circuit is ins

A combined low-voltage, low-power band-gap reference and temperature sensor circuit is provided for providing a band-gap reference parameter and for sensing the temperature of a chip, such as an eDRAM memory unit or CPU chip, using the band-gap reference parameter. The combined sensor circuit is insensitive to supply voltage and a variation in the chip temperature. The power consumption of both circuits, i.e., the band-gap reference and the temperature sensor circuits, encompassing the combined sensor circuit is less than one μW. The combined sensor circuit can be used to monitor local or global chip temperature. The result can be used to (1) regulate DRAM array refresh cycle time, e.g., the higher the temperature, the shorter the refresh cycle time, (2) to activate an on-chip or off-chip cooling or heating device to regulate the chip temperature, (3) to adjust internally generated voltage level, and (4) to adjust the CPU (or microprocessor) clock rate, i.e., frequency, so that the chip will not overheat. The combined band-gap reference and temperature sensor circuit of the present invention can be implemented within battery-operated devices having at least one memory unit. The low-power circuits of the sensor circuit extend battery lifetime and data retention time of the cells of the at least one memory unit.

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1. A temperature sensor circuit for an integrated circuit chip, said circuit comprising:means for generating a reference parameter, the means for generating including a reference circuit comprising: a first and a second diode, where said second diode is connected in series with a first resistor, a f

1. A temperature sensor circuit for an integrated circuit chip, said circuit comprising:means for generating a reference parameter, the means for generating including a reference circuit comprising: a first and a second diode, where said second diode is connected in series with a first resistor, a first amplifier having a positive input connected to said first resistor and a negative input connected to said first diode, said first amplifier having an output outputting a current output, said output being connected to at least a first set of transistors, and a second amplifier having a negative input connected to said first diode and a positive input connected to a second resistor, said second amplifier having an output outputting a current output, said output being connected to at least a second set of transistors; and means for sensing the on-chip temperature of said integrated circuit chip by utilizing at least said reference parameter, wherein said current output of said first amplifier is mirrored and multiplied by a ratio of about Wi/Wo, where Wi corresponds to the width of one of four transistors of said means for sensing the on-chip temperature and Wo corresponds to the width of said at least said first set of transistors. 2. The sensor circuit according to claim 1, wherein said reference parameter is a temperature independent band-gap reference voltage.3. The sensor circuit according to claim 1, wherein said reference parameter is a temperature dependent band-gap reference current.4. The sensor circuit according to claim 1, wherein said second diode has a cross-sectional area which is approximately sixteen times larger than the cross-sectional area of said first diode.5. The sensor circuit according to claim 1, wherein said current output of said first amplifier and said current output of said second amplifier are added and multiplied by a resistor value to obtain a band-gap reference voltage.6. The sensor circuit according to claim 1, wherein said current output of said first amplifier has a positive temperature coefficient and said current output of said second amplifier has a negative temperature coefficient.7. The sensor circuit according to claim 1, wherein said reference circuit further comprises a third resistor coupled to at least one of said second set of transistors.8. The sensor circuit according to claim 7, wherein said reference circuit further comprises:a first by-pass transistor parallel to a first high-resistance resistor in series with said first resistor; a second by-pass transistor parallel to a second high-resistance resistor in series with said second resistor; a third by-pass transistor parallel to a third high-resistance resistor in series with said third resistor; and means for receiving a control signal connected to said first, second and third by-pass transistors, wherein said control signal controls whether said reference circuit by-passes said first, second and third high-resistance resistors to reduce the DC current when said reference circuit is operated during low-power operations. 9. The sensor circuit according to claim 7, wherein said first resistor has a resistance value of approximately 10 k-ohms, said second resistor has a resistance value of approximately 83 k-ohms, and said third resistor has a resistance value of approximately 35 k-ohms.10. The sensor circuit according to claim 8, wherein said first high-resistance resistor, said second high-resistance resistor and said third high-resistance resistor have a resistance value of approximately nine times the resistance value of said first resistor, second resistor and said third resistor, respectively.11. The sensor circuit according to claim 1, wherein said means for sensing said on-chip temperature includes a temperature sensing circuit comprising:a third amplifier having a positive input connected to said first diode and a negative input connected to a fourth resistor, said third amplifier having an output outputting a current output, said output being connected to at least a third set of transistors; a fifth resistor connected to a first transistor of said at least said third set of transistors; a sixth resistor connected to a second transistor of said at least said third set of transistors; a seventh resistor connected to a third transistor of said at least said third set of transistors; a eight resistor connected to a fourth transistor of said at least said third set of transistors; a set of amplifiers having a positive input connected to a corresponding one of said fifth, sixth, seventh and eighth resistors and a negative input connected to said reference parameter, each of said set of amplifiers having an output outputting a temperature dependent voltage. 12. The sensor circuit according to claim 1, wherein said means for sensing said on-chip temperature includes a temperature sensing circuit comprising:a third set of transistors having different widths connected to said output of said first amplifier and a corresponding transistor of a fourth set of transistors; and a transistor being connected to each of said fourth set of transistors and at least one of said second set of transistors, each of said third set of transistors outputting a temperature dependent current. 13. The sensor circuit according to claim 7, further comprising means for sampling the reference parameter.14. The sensor circuit according to claim 13, wherein said means for sampling the reference parameter comprises:means for establishing the reference parameter; means for holding the value of the reference parameter; and means for floating the value of the reference parameter to a predetermined level. 15. The sensor circuit according to claim 14, wherein said means for establishing the reference parameter comprises:a logic gate having at least one output and at least two inputs for receiving a sampling signal and a control signal; and a set of transistors for receiving the at least one output and establishing the reference parameter according to the logic level of the at least two inputs, where a corresponding transistor of said set of transistors is in series with said first diode, said second diode, said second resistor, and said third resistor. 16. The sensor circuit according to claim 15, wherein said logic gate is an OR gate.17. The sensor circuit according to claim 14, wherein said means for holding the value of the reference parameter is a capacitor connected to at least one of said second set of transistors.18. A band-gap reference circuit for generating a band-gap reference parameter, said circuit comprising:a first and a second diode, where said second diode is connected in series with a first resistor; a first amplifier having a positive input connected to said first resistor and a negative input connected to said first diode, said first amplifier having an output outputting a current output, said output being connected to at least a first set of transistors, said current output being mirrored and multiplied by a ratio of about Wi/Wo, where Wi corresponds to a width of one of four transistors of a means for sensing an on-chip temperature and Wo corresponds to a width of said first set of transistors; and a second amplifier having a negative input connected to said first diode and a positive input connected to a second resistor; said second amplifier having an output outputting a current output, said output being connected to at least a second set of transistors. 19. The reference circuit according to claim 18, wherein said second diode has a cross-sectional area which is approximately sixteen times larger than the cross-sectional area of said first diode.20. The reference circuit according to claim 18, wherein said current output of said first amplifier and said current output of said second amplifier are added and multiplied by a resistor value to obtain a band-gap reference voltage.21. The reference circuit according to claim 18, wherein said current output of said first amplifier has a positive temperature coefficient and said current output of said second amplifier has a negative temperature coefficient.22. The reference circuit according to claim 18, wherein said reference circuit further comprises a third resistor coupled to at least one of said second set of transistors.23. The reference circuit according to claim 22, wherein said reference circuit further comprises:a first by-pass transistor parallel to a first high-resistance resistor in series with said first resistor; a second by-pass transistor parallel to a second high-resistance resistor in series with said second resistor; a third by-pass transistor parallel to a third high-resistance resistor in series with said third resistor; and means for receiving a control signal connected to said first, second and third by-pass transistors, wherein said control signal controls whether said reference circuit by-passes said first, second and third high-resistance resistors to reduce the DC current when said reference circuit is operated during low-power operations. 24. The reference circuit according to claim 22, wherein said first resistor has a resistance value of approximately 10 k-ohms, said second resistor has a resistance value of approximately 83 k-ohms, and said third resistor has a resistance value of approximately 35 k-ohms.25. The reference circuit according to claim 23, wherein said first high-resistance resistor, said second high-resistance resistor and said third high-resistance resistor have a resistance value of approximately nine times the resistance value of said first resistor, second resistor and said third resistor, respectively.26. A band-gap reference and temperature sensor circuit for generating a band-gap reference and sensing the on-chip temperature of an integrated circuit chip, said sensor circuit comprising:a first circuit for generating said band-gap reference, the first circuit comprising: a first amplifier having a positive input connected to a first resistor and a negative input connected to a first diode, and an output connected to at least a first set of transistors, said output being mirrored and multiplied by a ratio of about Wi/Wo, where Wi corresponds to the width of one of four transistors of said sensor circuit and Wo corresponds to the width of said at least said first set of transistors, wherein said first resistor is connected in series with a second diode, a second amplifier having a negative input connected to said first diode and a positive input connected to a second resistor; and a second circuit connected to said first circuit for receiving at least said band-gap reference, generating temperature dependent voltage or current values, and for sensing the on-chip temperature of said integrated circuit chip by utilizing at least said band-gap reference and said temperature dependent voltage or current values. 27. The sensor circuit according to claim 26, wherein said band-gap reference is an temperature independent band-gap reference voltage having a low-voltage value.28. The sensor circuit according to claim 26, wherein said band-gap reference is a temperature dependent band-gap reference current having a low-current value.29. The sensor circuit according to claim 26, wherein said first and second circuits are capable of operating when a supply voltage to said circuits is less than 1.0 volt.30. The sensor circuit according to claim 26, wherein said integrated circuit chip is an embedded dynamic random access memory unit (eDRAM).