Temperature Sensing Circuit for Semiconductor Memory

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Solution Overview

Problem

Conventional temperature sensors in semiconductor memory devices are large in size and consume high current due to multiple operational amplifiers, making them unsuitable for battery-operated systems where low current consumption is essential, especially for sensing high temperatures.

Innovation Solution

A temperature sensing circuit that generates a reference voltage and a variable voltage based on temperature fluctuations, using resistance elements and transistors to reduce size and current consumption, with a comparison unit and control circuit to detect ambient temperature and control self-refresh operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional temperature sensors with multiple operational amplifiers are used, then temperature sensing accuracy is improved, but chip size and current consumption increase

Engineering Contradiction:

Improvetemperature sensing accuracyVSAvoidcurrent consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts and removes the multiple operational amplifiers from the temperature sensing circuit, retaining only the essential temperature sensing functionality. This reduction eliminates unnecessary components that consume current, while the core sensing mechanism using temperature-sensitive transistors and voltage dividers maintains adequate temperature detection capability for determining self-refresh periods.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces complex, high-current-consuming operational amplifiers with simpler, lower-cost circuit elements such as voltage dividers and temperature-sensitive transistors. These simpler components achieve the necessary temperature sensing function with significantly reduced current consumption, accepting that the sensing precision is sufficient for the specific application of determining refresh periods rather than providing high-precision temperature measurement.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If conventional temperature sensors with multiple operational amplifiers are used, then temperature sensing accuracy is improved, but chip size increases

Engineering Contradiction:

Improvetemperature sensing accuracyVSAvoidchip size

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent extracts and removes the multiple operational amplifiers from the temperature sensing circuit, retaining only the essential temperature sensing functionality. This reduction eliminates unnecessary components that occupy chip area, while the core sensing mechanism using temperature-sensitive transistors and voltage dividers maintains adequate temperature detection capability for determining self-refresh periods.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces complex, space-consuming operational amplifiers with simpler circuit elements such as voltage dividers and temperature-sensitive transistors. These simpler components achieve the necessary temperature sensing function with significantly reduced chip area occupation, as they require fewer transistors and less interconnect wiring compared to operational amplifiers.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If multiple operational amplifiers are used in temperature sensor, then sensing operation is improved, but current consumption increases

Engineering Contradiction:

Improvesensing operationVSAvoidcurrent consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

4Adaptability or versatility

If conventional temperature sensors are used, then comprehensive temperature monitoring is achieved, but device complexity increases

Engineering Contradiction:

Improvetemperature monitoring capabilityVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the multiple operational amplifiers from the temperature sensing circuit, retaining only the essential temperature sensing functionality. This reduction eliminates unnecessary components, while the core sensing mechanism using temperature-sensitive transistors and voltage dividers maintains adequate temperature detection capability for determining self-refresh periods.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The simplified temperature sensing circuit is designed to perform the essential function of detecting high temperature conditions that require self-refresh operations. Rather than providing comprehensive temperature monitoring across multiple ranges and modes, the circuit is optimized for the specific function of determining when self-refresh periods are needed, making it more suitable for mobile devices with limited power and area resources.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution reduces chip size and current consumption while accurately detecting high temperatures, enabling efficient control of self-refresh periods and improving data retention characteristics in semiconductor memory devices.

Implementation Method 1

a reference voltage generating unit for dividing a driving voltage and generating the reference voltage, The reference voltage generating unit can include a plurality of voltage dividing elements in series connected between a terminal for receiving the driving voltage and a first node. The voltage dividing elements can be resistance elements.

Methodology Applied

Scientific EffectVoltage division: Ohm's Law

Implementation Method 2

a first temperature element connected between the first node and the second node, to generate the first voltage in response to the reference voltage

Methodology Applied

Scientific EffectTemperature-dependent voltage generation: Thermal Expansion

Implementation Method 3

an amplifying unit for generating the variable voltage in response to the first voltage. The amplifying unit can include a second level controlling element connected between the driving voltage supply terminal and a third node and a second temperature element connected between the first node and the third node to generate the variable voltage in response to the first voltage.

Methodology Applied

Scientific EffectTemperature-dependent voltage amplification: Thermal Expansion

Implementation Method 4

a comparison unit for comparing the reference voltage to the variable voltage, detecting an ambient temperature and generating a temperature detecting signal

Methodology Applied

Scientific EffectVoltage comparison for temperature detection:

Data Source

PatentUS8545095B2Temperature sensing circuit and semiconductor memory device using the same

Publication Date: 2013.10.01 SK HYNIX INC

AI summary

A temperature sensing circuit comprises a temperature sensing unit for generating a reference voltage having a constant level, regardless of a temperature fluctuation, and a variable voltage to be changed according to the temperature fluctuation, and a comparison unit for comparing the reference voltage to the variable voltage, detecting an ambient temperature and generating a temperature detecting signal.