Bandgap Temperature Sensor Eliminates Op-Amp for Low Power

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Solution Overview

Problem

Conventional analog temperature sensors in electronic circuits occupy significant chip area and consume high power due to the use of operational amplifiers, which are not efficient for environmental temperature detection.

Innovation Solution

A bandgap temperature sensor system that generates multiple base-emitter voltages and a system controller to produce a bandgap reference voltage, which remains constant with temperature variations, using a variable current source and analog-to-digital converter to detect and process these voltages, thereby reducing power consumption and chip area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional analog temperature sensors with operational amplifiers are used, then temperature detection function is achieved, but chip area and power consumption increase

Engineering Contradiction:

Improvetemperature detection functionVSAvoidchip area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts and removes the operational amplifier from the temperature sensor circuit, retaining only the essential components (transistors, diodes, resistors) needed for temperature detection. This extraction eliminates the large area-consuming op-amp while preserving the core temperature sensing functionality through direct base-emitter voltage measurement.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses digital copying of the base-emitter voltage signals through analog-to-digital conversion, allowing the temperature information to be replicated and processed in digital form rather than requiring continuous analog processing with operational amplifiers. This digital representation maintains temperature detection accuracy while reducing analog circuit complexity.

Inventive Principle:

Principle #26Copying

2Reliability

If conventional analog temperature sensors with operational amplifiers are used, then temperature detection function is achieved, but power consumption increases

Engineering Contradiction:

Improvetemperature detection functionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The operational amplifier is extracted and removed from the circuit, eliminating its continuous power consumption. The temperature detection function is maintained using only the power needed for the variable current source and ADC, significantly reducing overall power usage while preserving detection accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs periodic sampling of the base-emitter voltage through a variable current source that sequentially applies different current levels. This periodic measurement approach replaces continuous analog processing, reducing power consumption while maintaining temperature detection functionality through discrete measurements.

Inventive Principle:

Principle #19Periodic action

3Ease of operation

If operational amplifiers are used in temperature sensors, then analog signal processing is achieved, but device complexity increases

Engineering Contradiction:

Improveanalog signal processingVSAvoidcircuit complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent substitutes analog signal processing (mechanical/electrical continuous processing) with digital signal processing. Base-emitter voltages are converted to digital signals via ADC, allowing temperature calculation to be performed through digital arithmetic operations in a processor, thereby simplifying the analog circuit while maintaining processing capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters by using a variable current source that applies discrete current levels to the transistor rather than continuous analog currents. This parameter discretization enables digital measurement and processing, reducing analog circuit complexity while preserving temperature detection accuracy through multiple measurement points.

Inventive Principle:

Principle #35Parameter changes

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 system effectively generates a temperature-insensitive bandgap voltage reference, reducing power consumption and chip area by utilizing a microprocessor to calculate the bandgap voltage reference from detected base-emitter voltages, ensuring stability across environmental temperature fluctuations.

Implementation Method 1

A bandgap temperature sensor generates multiple base-emitter voltages... The base-emitter voltages decrease as the environmental temperature increases

Methodology Applied

Scientific EffectBase-emitter voltage temperature dependence:

Implementation Method 2

an analog-to-digital converter to convert base-emitter voltages into digital base-emitter voltage signals

Methodology Applied

Scientific EffectAnalog-to-digital conversion:

Data Source

PatentUS8130025B2Numerical band gap

Publication Date: 2012.03.06 MONTEREY RESEARCH LLC

AI summary

A system includes a bandgap temperature sensor to generate multiple base-emitter voltages. The system also include a controller to detect the base-emitter voltages generated by the bandgap temperature sensor and to generate a bandgap reference voltage according to the multiple base-emitter voltage signals, the bandgap reference voltage having a voltage level that remains substantially constant relative to environmental temperature variations.