EP-4739985-A1 - TEMPERATURE SENSING FOR SEMICONDUCTOR DEVICES

EP4739985A1EP 4739985 A1EP4739985 A1EP 4739985A1EP-4739985-A1

Abstract

This document describes systems and techniques directed at temperature sensing for semiconductor devices. In aspects, a temperature sensor includes an oscillator whose output frequency varies as a function of temperature. One or more attributes associated with the oscillator output can be determined to generate a value corresponding to a temperature at one or more temperature-sensitive resistors of the oscillator. In this way, a compact temperature sensor can be implemented on a semiconductor device to measure a temperature of a region of the semiconductor device without analog input/outputs and a dedicated supply power.

Inventors

ROSHAN, MEISAM HEIDARPOUR
SALVIA, JAMES CHRISTIAN

Assignees

Google LLC

Dates

Publication Date: 20260513
Application Date: 20240402

Claims (15)

1. A temperature sensor comprising: an oscillator configured to generate a variable frequency output based on a temperature, the oscillator comprising: a first circuit including a first temperature-sensitive resistor and a first capacitor, the first capacitor configured to charge towards a first voltage at a first rate based on the temperature at the first temperature-sensitive resistor; a second circuit including a second temperature-sensitive resistor and a second capacitor, the second capacitor configured to discharge towards a second voltage at a second rate based on the temperature at the second temperature-sensitive resistor, the second voltage less than the first voltage; a comparator having a non-inverting input operatively coupled to the first circuit and an inverting input operatively coupled to the second circuit; and at least one switch configured to switch, based on a change in polarity between the non-inverting input and the inverting input, (i) the first circuit from being charged towards the first voltage to being discharged towards the second voltage and (ii) the second circuit from being discharged towards the second voltage to being charged towards the first voltage effective to cause the oscillator to generate the variable frequency output; a counter module operatively coupled to the oscillator and configured to determine one or more attributes associated with the variable frequency output; and a conversion module operatively coupled to the counter module and configured to generate, based on the determined one or more attributes associated with the variable frequency output, a value corresponding to the temperature.
2. The temperature sensor of claim 1, wherein the counter module configured to determine one or more attributes associated with the variable frequency output is configured to determine a number of rising edges in the variable frequency output within a predetermined time frame.
3. The temperature sensor of claim 2, wherein the conversion module configured to generate the value corresponding to the temperature is configured to generate the value corresponding to the temperature by converting the number of rising edges in the variable frequency output within the predetermined time frame using a second order or third order polynomial.
4. The temperature sensor of any of the preceding claims, wherein the first voltage comprises a supply voltage (VDD) and the second voltage comprises a ground voltage.
5. The temperature sensor of any of the preceding claims, wherein the first temperature-sensitive resistor and the second temperature-sensitive resistor comprise routing metal layers.
6. The temperature sensor of any of the preceding claims, wherein: the first temperature-sensitive resistor comprises a first temperature coefficient of resistance and the second temperature-sensitive resistor comprises a second temperature coefficient of resistance, the first temperature coefficient of resistance being approximately equal to the second temperature coefficient of resistance; and the first capacitor comprises a first capacitance and the second capacitor comprises a second capacitance, the first capacitance being approximately equal to the second capacitance.
7. The temperature sensor of any of the preceding claims, wherein the first circuit and the second circuit are integrated into a third circuit.
8. The temperature sensor of any preceding claim, wherein a duration of time between a first change in polarity between the non-inverting input and the inverting input and a second change in polarity between the non-inverting input and the inverting input is approximated by time [T]: T = RC x ln(2) with R denoting at least one of a first resistance of the first temperature-sensitive resistor or a second resistance of the second temperature-sensitive resistor, and C denoting at least one of the first capacitance of the first capacitor or the second capacitance of the second capacitor.
9. The temperature sensor of any of the preceding claims, wherein the oscillator comprises a resistor-capacitor (RC) relaxation oscillator.
10. The temperature sensor of any of the preceding claims, wherein the oscillator is configured to provide the variable frequency output having (i) a first value for a first polarity between the non-inverting input and the inverting input or (ii) a second value for a second polarity between the non-inverting input and the inverting input.
11. The temperature sensor of claim 10, wherein the first value is a binary value of one and the second value is a binary value of zero.
12. The temperature sensor of any of the preceding claims, wherein before the at least one switch is configured to switch (i) the first circuit from being charged towards the first voltage to being discharged towards the second voltage and (ii) the second circuit from being discharged towards the second voltage to being charged the first voltage, the at least one switch is further configured to: switch, based on a change in polarity between the non-inverting input and the inverting input, the first capacitor of the first circuit from being charged towards the first voltage via the first temperature-sensitive resistor to being charged towards the first voltage through a low-resistance path that bypasses the first temperature-sensitive resistor effective to increase a first capacitor voltage of the first capacitor to approximately the first voltage; and switch, based on a change in polarity between the non-inverting input and the inverting input, the second capacitor of the second circuit from being discharged towards the second voltage via the second temperature-sensitive resistor to being discharged towards the second voltage through a low-resistance path that bypasses the second temperature-sensitive resistor effective to decrease a second capacitor voltage of the second capacitor to approximately the second voltage.
13. The temperature sensor of any of the preceding claims, wherein the temperature sensor is mounted on a semiconductor device.
14. An electronic device comprising the temperature sensor of any of claims 1-13.
15. The electronic device of claim 14, further comprising: at least one processor; and a computer-readable storage medium comprising instructions that when executed by the at least one processor cause the at least one processor to: determine a temperature of at least one element based on the value corresponding to the temperature; and adjust, based on the determined temperature, at least one of a current or a voltage received by the at least one element.

Description

TEMPERATURE SENSING FOR SEMICONDUCTOR DEVICES BACKGROUND [0001] Electronic devices play integral roles in manufacturing, communication, transportation, healthcare, commerce, social interaction, and entertainment. For instance, electronic devices power server farms that provide cloud-based computing functionality for commerce and communication. Electronic devices are also embedded in many different types of modem equipment, such as medical devices, automobiles, and industrial tools. With electronic devices becoming pervasive and crucial to many aspects of modern life, device performance and reliability are paramount. [0002] Electronic devices consist of general-purpose and/or application-specific semiconductor devices, such as application processors, micro-electromechanical systems (MEMS) sensors, microcontrollers, and similar components. These semiconductor devices enable electronic devices to provide a wide range of services and functions. As these constituent components of electronic devices advance, so too will overall device performance and reliability. [0003] This Background section is provided to generally present the context of the disclosure. Unless otherwise indicated herein, material described in this section is neither expressly nor implicitly admitted to be prior art to the present disclosure or the appended claims. SUMMARY [0004] This document describes systems and techniques directed at temperature sensing for semiconductor devices. In aspects, a temperature sensor includes an oscillator whose output frequency varies as a function of temperature. One or more attributes associated with the oscillator output can be determined to generate a value corresponding to a temperature at one or more temperature-sensitive resistors of the oscillator. In this way, a compact temperature sensor can be implemented on a semiconductor device to measure a temperature of a region of the semiconductor device without analog input/outputs and a dedicated supply power. [0005] In aspects, a temperature sensor is disclosed that includes an oscillator configured to generate a variable frequency output based on a temperature. The oscillator includes a first circuit including a first temperature-sensitive resistor and a first capacitor. The first capacitor is configured to charge towards a first voltage at a first rate based on the temperature at the first temperature-sensitive resistor. The oscillator further includes a second circuit including a second temperature-sensitive resistor and a second capacitor. The second capacitor is configured to discharge towards a second voltage at a second rate based on the temperature at the second temperature-sensitive resistor. The second voltage is less than the first voltage. The oscillator further includes a comparator having a non-inverting input operatively coupled to the first circuit and an inverting input operatively coupled to the second circuit. Additionally, the oscillator includes at least one switch configured to switch, based on a change in polarity between the noninverting input and the inverting input, (i) the first circuit from being charged towards the first voltage to being discharged towards the second voltage and (ii) the second circuit from being discharged towards the second voltage to being charged towards the first voltage. The temperature sensor further includes a counter module operatively coupled to the oscillator and configured to determine one or more attributes associated with the variable frequency output. The temperature sensor also includes a conversion module operatively coupled to the counter module and configured to generate, based on the determined one or more attributes associated with the variable frequency output, a value corresponding to the temperature. The phrase “a polarity between the two inputs” may be used interchangeably with the phrase “a polarity of a difference between the two inputs”. [0006] In additional aspects, a method is disclosed that includes generating a first clock signal and determining a first change in polarity between a non-inverting input and an inverting input (or a difference therebetween). Responsive to determining the first change in polarity and until determining a second change in polarity between the non-inverting input and the inverting input of the temperature-sensitive oscillator, the method includes (i) generating a second clock signal; (ii) charging a first capacitor, via a first resistor, towards a first voltage at a first rate, the charging at the first rate based on a temperature of the first resistor; and (iii) discharging a second capacitor, via a second resistor, towards a second voltage at a second rate, the discharging at the second rate based on a temperature of the second resistor. The method further includes continuing to determine a sequence of changes in polarity between the non-inverting input and the inverting input of the temperature-sensitive oscillator effective to cause the temperature