# US 2025/0093218 A1 · Temperature sensor with delta base-emitter voltage amplification and digital curvature correction

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- Number: US 2025/0093218 A1
- Document ID: US20250093218A1
- Status: Published application
- Kind: A1
- Application number: 18/961,020
- Filed: 2024-11-26
- Published: 2025-03-20
- Earliest claimed: 2021-11-12
- Assignees: Analog Devices International Unlimited Company
- Applicants: Analog Devices International Unlimited Company
- Inventors: Gaurav SINGH; Wreeju BHAUMIK
- Web page: https://patentgrep.com/patent/US20250093218A1

## CPC

- G01K 15/005: {Calibration}
- G01K 7/01: using semiconducting elements having PN junctions (G01K7/02, G01K7/16, G01K7/30 take precedence)
- G01K 2219/00: Thermometers with dedicated analog to digital converters
- G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00)

## Abstract

Systems, devices, and methods related to temperature sensors for electronic devices are provided. An example temperature sensor device includes analog temperature sensor circuitry to generate a plurality of voltages indicative of a temperature; an analog-to-digital converter (ADC) disposed downstream of the analog temperature sensing circuitry; switched-capacitor amplifier circuitry disposed before the ADC, the switched-capacitor amplifier circuitry comprising a single-ended amplifier to amplify the plurality of voltages with respect to a common voltage; a first switch coupled between the analog temperature sensor circuitry and the switched-capacitor amplifier circuitry to provide a sampling phase and an integration phase; and digital calculation circuitry to calculate a temperature value based on the plurality of amplified voltages.

## Claims

### Claim 1

An integrated circuit device comprising:
a temperature measurement system comprising:
analog temperature sensor circuitry configured to generate a plurality of voltages indicative of a temperature;
switched-capacitor amplifier circuitry comprising a single-ended amplifier configured to amplify the plurality of voltages with respect to a common voltage;
a first switch disposed between the analog temperature sensor circuitry and the switched-capacitor amplifier circuitry; and
digital calculation circuitry configured to calculate a temperature value based on the plurality of amplified voltages;
a component; and
processing circuitry configured to:
receive an indication of the calculated temperature value; and
adjust an operation of the component responsive to the indication.

### Claim 2 (depends on 1)

The integrated circuit device of claim 1, wherein:
the analog temperature sensor circuitry comprises:
a first transistor comprising a first base, a first emitter, and a first collector; and
a plurality of first current sources configured to provide N instances of a first amount of current to the first transistor and a second amount of current, wherein the second amount of current is N times the first amount of current, and wherein the first transistor is configured to generate a respective first base-emitter voltage responsive to each instance of the N instances of the first amount of current and a second base-emitter voltage responsive to the second amount of current; and
the switched-capacitor amplifier circuitry configured to amplify each of the first base-emitter voltages and the second base-emitter voltage with respect to the common voltage.

### Claim 3 (depends on 2)

The integrated circuit device of claim 2, further comprising:
biasing circuitry comprising:
a second transistor comprising a second base, a second emitter coupled to a second input of the single-ended amplifier, and a second collector; and
a second current source to provide a third amount of current to the second transistor, wherein the second transistor generates a third base-emitter voltage responsive to the third amount of current, and wherein the third base-emitter voltage is provided as the common voltage to the switched-capacitor amplifier circuitry.

### Claim 4 (depends on 3)

The integrated circuit device of claim 3, wherein:
the temperature measurement system further comprises:
an analog-to-digital converter (ADC) configured to convert each of the amplified first base-emitter voltages to a respective first digital value and the amplified second base-emitter voltage to a second digital value; and
an accumulator to accumulate the first digital values to generate a third digital value; and
the digital calculation circuitry further configured to:
calculate the temperature value further based on the second digital value, the third digital value, and a predetermined scaling factor associated with at least an inverse of a digital bandgap reference; and
adjust the temperature value based on a predetermined offset value associated with at least a temperature-dependent digital bandgap reference compensation.

### Claim 5 (depends on 2)

The integrated circuit device of claim 2, further comprising a multiplexer configured to:
receive a selection signal;
selectively couple to the first emitter of the first transistor or an output of the single-ended amplifier of the switched-capacitor amplifier circuitry based on the selection signal; and
output a first voltage of the first emitter or a second voltage of the output of the single-ended amplifier based on the selection signal.

### Claim 6 (depends on 2)

The integrated circuit device of claim 2, wherein the plurality of first current sources are matched.

### Claim 7 (depends on 1)

The integrated circuit device of claim 1, wherein the switched-capacitor amplifier circuitry further comprises:
a first capacitor disposed at a first input of the single-ended amplifier; and
a second capacitor disposed between the first input and an output of the single-ended amplifier.

### Claim 8 (depends on 7)

The integrated circuit device of claim 7, wherein a first capacitance of the first capacitor is larger than a second capacitance of the second capacitor.

### Claim 9 (depends on 8)

The integrated circuit device of claim 8, wherein a ratio of the first capacitance to the second capacitance is substantially identical to a number of a plurality of first current sources of the analog temperature sensor circuitry.

### Claim 10

A method of measuring a temperature by an integrated circuit device, comprising:
generating, via analog temperature sensor circuitry, a plurality of voltages indicative of the temperature;
closing a first switch coupled between the analog temperature sensor circuitry and switched-capacitor amplifier circuitry;
amplifying, via the switched-capacitor amplifier circuitry comprising a single-ended amplifier, the plurality of voltages with respect to a common voltage in response to closing the first switch;
calculating, via digital calculation circuitry, a temperature value based on the plurality of amplified voltages; and
adjusting, via processing circuitry, an operation of a component responsive to the temperature value.

### Claim 11 (depends on 10)

The method of claim 10, wherein the analog temperature sensor circuitry comprises a first transistor comprising a first base, a first emitter, and a first collector; and
the method further comprises:
providing, via a plurality of first current sources of the analog temperature sensor circuitry, N instances of a first amount of current to the first transistor and a second amount of current, wherein the second amount of current is N times the first amount of current; and
generating, via the first transistor, a respective first base-emitter voltage responsive to each instance of the N instances of the first amount of current and a second base-emitter voltage responsive to the second amount of current;
wherein amplifying, via the switched-capacitor amplifier circuitry, the plurality of voltages comprises amplifying each of the first base-emitter voltages and the second base-emitter voltage with respect to the common voltage.

### Claim 12 (depends on 11)

The method of claim 11, wherein the integrated circuit device comprises biasing circuitry comprising a second transistor comprising a second base, a second emitter coupled to a second input of the single-ended amplifier, and a second collector; and
the method further comprises:
providing, via a second current source, a third amount of current to the second transistor,
generates, via the second transistor, a third base-emitter voltage responsive to the third amount of current, and
providing the third base-emitter voltage as the common voltage to the switched-capacitor amplifier circuitry.

### Claim 13 (depends on 12)

The method of claim 12, further comprising:
converting, via an analog-to-digital converter (ADC) of the integrated circuit device, each of the amplified first base-emitter voltages to a respective first digital value and the amplified second base-emitter voltage to a second digital value;
accumulating, via an accumulator of the integrated circuit device, the first digital values to generate a third digital value;
wherein:
calculating the temperature value further comprises calculating, via the digital calculation circuitry, based on the second digital value, the third digital value, and a predetermined scaling factor associated with at least an inverse of a digital bandgap reference; and
adjusting the temperature value further comprises adjusting based on a predetermined offset value associated with at least a temperature-dependent digital bandgap reference compensation.

### Claim 14 (depends on 11)

The method of claim 11, further comprising:
receiving, via a multiplexer, a selection signal;
selectively coupling, via the multiplexer, to the first emitter of the first transistor or an output of the single-ended amplifier of the switched-capacitor amplifier circuitry based on the selection signal; and
outputting, via the multiplexer, a first voltage of the first emitter or a second voltage of the output of the single-ended amplifier based on the selection signal.

### Claim 15

A method of measuring a temperature, the method comprising:
during a first phase:
sampling a common voltage of switched-capacitor amplifier circuitry;
during a second phase:
injecting a first amount of current into a transistor to generate a first base-emitter voltage at the transistor;
injecting a second amount of current into the transistor to generate a second base-emitter voltage at the transistor;
amplifying, via the switched-capacitor amplifier circuitry, the first base-emitter voltage and the second base-emitter voltage with respect to the common voltage; and
determining a temperature value based at least in part on the amplified first base-emitter voltage and the amplified second base-emitter voltage.

### Claim 16 (depends on 15)

The method of claim 15, further comprising:
injecting a third amount of current into another transistor to generate a third base-emitter voltage at the other transistor, wherein the other transistor is coupled to an input of the switched-capacitor amplifier circuitry to provide the third base-emitter voltage as the common voltage at the input of the switched-capacitor amplifier circuitry.

### Claim 17 (depends on 15)

The method of claim 15, wherein:
the injecting the first amount of current to the transistor comprises:
injecting N instances of the first amount of current to the transistor to generate a respective first base-emitter voltage at the transistor for each instance, where N is an integer greater than 1; and
the second amount of current is N times the first amount of current; and
the amplifying the first base-emitter voltage and the second base-emitter voltage further comprises:
amplifying, via the switched-capacitor amplifier circuitry, each of the first base-emitter voltages with respect to the common voltage by a factor of N.

### Claim 18 (depends on 17)

The method of claim 17, wherein the determining the temperature value comprises:
converting, via an analog-to-digital-converter (ADC), each of the first base-emitter voltages to a respective first digital value and the second base-emitter voltage to a second digital value;
accumulating the first digital values to generate a third digital value;
subtracting the third digital value from the second digital value to generate a fourth digital value indicative of an amplified base-emitter difference voltage difference; and
multiplying the fourth digital value by a predetermined scaling factor associated with at least an inverse of a digital bandgap reference to produce a fifth digital value.

### Claim 19 (depends on 18)

The method of claim 18, further comprising:
adjusting the temperature value by a predetermined temperature-dependent digital compensation value.

### Claim 20 (depends on 15)

The method of claim 15, further comprising:
during the first phase:
causing a first switch to open, the first switch coupled between an emitter of the transistor and the switched-capacitor amplifier circuitry; and
causing a second switch and a third switch to close, the second switch coupled between a first input and an output of a single-ended amplifier of the switched-capacitor amplifier circuitry, and the third switch coupled between the first input and a second input of the single-ended amplifier; and
during a third phase between the first phase and the second phase:
causing the second switch and the third switch to open while the first switch is opened; and
during the second phase:
causing the first switch to close while the second switch and the third switch are opened.