SEMICONDUCTOR TEMPERATURE SENSOR WITH HIGH SENSITIVITY

• US 20140023114A1
• Filed: 09/23/2013
• Published: 01/23/2014
• Est. Priority Date: 01/04/2006
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Liu, Bo
• Granted Patent: US 9,464,942 B2
• Time in Patent Office: Days
• US Class Current: 374/178
• CPC Class Codes: G01K 7/01 using semiconducting elements having PN junctions G01K7/02, G01K7/16, G01K7/30 take precedence
• CPC Class Codes: G05F 3/267 using both bipolar and field-effect technology

Abstract

An temperature sensor circuit is disclosed. In one embodiment, the temperature sensor comprises an input circuit with a current mirror for forcing a current down a reference stage and an output stage. The reference stage and the output stage include P-N junctions (e.g., using bipolar transistors) with differing junction potentials. By tailoring the resistances in the reference and output stages, the input circuit produces two output voltages, one of which varies predictably with temperature, and one which is stable with temperature. The input circuit is preferably used in conjunction with an amplifier stage which preferably receives both the temperature-sensitive and non-temperature-sensitive outputs. Through various resistor configurations in the amplifier stage, the output of the temperature sensor can be made to vary at a higher sensitivity than produced by the temperature-sensitive output of the input circuit. Moreover, as a result of the non-temperature-sensitive output, the output of the temperature sensor is additionally and beneficially tailored in its offset voltage in a temperature-independent manner. The result is a flexible circuit that can achieve very high sensitivities and near-ideal performance even at lower power supply voltages.

Claims

1. A temperature sensor, comprising:

an input circuit for producing a first output voltage that varies predictably with temperature at a first temperature sensitivity and a second output voltage that does not vary with temperature; and

an amplifier stage for receiving the first and second output voltages, wherein the first output voltage and the second output voltage are separated by a resistor in the input circuit.

2. The temperature sensor of claim 1, wherein the input circuit comprises a current mirror and P-N junctions that differ in their junction potentials, and further comprises adjustable resistors for producing the first and second output voltages.

3. The temperature sensor of claim 1, wherein the amplifier stage comprises a first operational amplifier for receiving the first output voltage, and a second operation amplifier for receiving the second output voltage.

4. The temperature sensor of claim 3, further comprising a third operational amplifier for generating an intermediate voltage.

5. The temperature sensor of claim 4, further comprising a fourth operational amplifier for receiving the intermediate voltage and producing the temperature sensor output.

6. The temperature sensor of claim 1, wherein the input circuit is to be powered by a power supply voltage, wherein the temperature sensor is designed to operate within a temperature range from a first temperature to a second temperature, and wherein the temperature sensor output is approximately the power supply voltage at the first temperature, and wherein the temperature sensor output is approximately ground at the second temperature.

7. The temperature sensor of claim 1, wherein the amplifier stage comprises a first amplifier for receiving the first output voltage and a second amplifier for receiving the second output voltage, wherein outputs from the first and second amplifiers are used to create an intermediate voltage with an adjustable offset voltage;

and a third amplifier for receiving the intermediate voltage and for producing the temperature sensor output.

8. The temperature sensor of claim 7, wherein the input circuit comprises a current mirror and P-N junctions that differ in their junction potentials, and further comprises adjustable resistors for producing the first and second output voltages.

9. The temperature sensor of claim 7, wherein the input circuit is powered by a power supply voltage, wherein the temperature sensor is designed to operate within a temperature range from a first temperature to a second temperature, and wherein the temperature sensor output is approximately the power supply voltage at the first temperature, and wherein the temperature sensor output is approximately ground at the second temperature.

10. The temperature sensor of claim 1, wherein the input circuit is operable at a power supply voltage;

and wherein the temperature sensor output is approximately the power supply voltage at a first temperature, and wherein the temperature sensor output is approximately ground at a second temperature.

11. The temperature sensor of claim 10, wherein the first output voltage and the second output voltages are separated by a resistor in the input circuit.

12. The temperature sensor of claim 10, wherein the input circuit comprises a current mirror and P-N junctions that differ in their voltage drops, and further comprises adjustable resistors for producing the first and second output voltages.

13. A temperature sensor, comprising:

an input circuit for producing a first output voltage that varies predictably with temperature at a first temperature sensitivity and a second output voltage that does not vary with temperature;

an first amplifier for receiving the first output voltage and a second amplifier for receiving the second output voltage; and

a third amplifier for receiving an intermediate voltage and for producing a temperature sensor output with a second temperature sensitivity higher than the first temperature sensitivity,

wherein the first output voltage and the second output voltage are separated by a resistor in the input circuit.

14. The temperature sensor of claim 13, wherein the input circuit comprises a current mirror and P-N junctions that differ in their junction potentials, and further comprises adjustable resistors for producing the first and second output voltages.

15. The temperature sensor of claim 13, wherein the third amplifier is configured to amplify the first temperature sensitivity to the second temperature sensitivity by a scalar.

16. The temperature sensor of claim 13, wherein the input circuit is to be powered by a power supply voltage, wherein the temperature sensor is designed to operate within a temperature range from a first temperature to a second temperature.

17. The temperature sensor of claim 13, wherein the temperature sensor output is approximately the power supply voltage at the first temperature.

18. The temperature sensor of claim 13, wherein the temperature sensor output is approximately ground at the second temperature.

19. A temperature sensor designed to operate within a temperature range from a first temperature to a second temperature, comprising:

an input circuit operable at a power supply voltage, the input circuit to produce a first output voltage that varies predictably with temperature at a first temperature sensitivity and a second output voltage that does not vary with temperature; and

an amplifier stage for receiving the first and second output voltages, the amplifier stage to produce a temperature sensor output with a second temperature sensitivity higher than the first temperature sensitivity, and wherein the first output voltage and the second output voltage are separated by a resistor in the input circuit.

20. The temperature sensor of claim 19, wherein the input circuit comprises a current mirror and P-N junctions that differ in their voltage drops, and further comprises adjustable resistors to produce the first and second output voltages.