Asymmetric Offset Compensation Circuit for Temperature Drift

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Solution Overview

Problem

Existing analog circuits, such as amplifiers, suffer from offset error and offset drift due to component mismatches and temperature variations, which cannot be effectively compensated for without introducing discontinuities in the analog signal.

Innovation Solution

The implementation of an asymmetric offset drift compensation circuit with low and high temperature compensation circuits, each generating offset compensation currents at different rates, to independently trim offset drift without affecting room temperature operation and causing signal discontinuities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If offset compensation is applied to correct offset error, then offset error is minimized, but offset drift variation with temperature cannot be effectively compensated

Engineering Contradiction:

Improveoffset error compensationVSAvoidoffset drift stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The offset compensation circuit is divided into multiple independent segments, each handling a specific temperature range. A first offset compensation circuit operates below a first temperature threshold, a second offset compensation circuit operates between the first and second temperature thresholds, and a third offset compensation circuit operates above the second temperature threshold. This segmentation allows each circuit to be optimized for its specific temperature range, effectively compensating for offset drift across the entire temperature spectrum while maintaining measurement precision.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If a single offset compensation circuit is used, then circuit complexity is reduced, but it cannot compensate for offset drift at different temperature rates

Engineering Contradiction:

Improvecompensation circuit structureVSAvoidtemperature range compensation

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The offset compensation system dynamically adapts to temperature changes by switching between different compensation circuits based on the current temperature. Temperature detection circuitry monitors the operating temperature and activates the appropriate compensation circuit (first, second, or third) to match the current temperature range. This dynamic adaptation enables the system to handle different temperature rates effectively without requiring a single overly complex circuit design.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The compensation system changes its operational parameters by switching between different compensation circuits with different compensation rates. Each circuit is designed with specific component values and characteristics optimized for its temperature range. As temperature changes, the system transitions to a circuit with appropriate parameters for that temperature regime, enabling effective offset drift compensation across varying temperature conditions.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If offset compensation is applied, then offset error is corrected, but discontinuities are introduced in the analog signal

Engineering Contradiction:

Improveoffset correction accuracyVSAvoidsignal continuity

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The offset compensation circuits are designed to provide smooth transitions between different temperature ranges. By anticipating temperature changes and having pre-configured compensation circuits ready for each temperature regime, the system can switch between compensation modes without introducing abrupt changes or discontinuities in the analog signal. The compensation amounts are carefully calibrated to ensure continuity at the transition points between different temperature ranges.

Inventive Principle:

Principle #10Preliminary action

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

This solution effectively compensates for offset drift at varying temperatures, addressing mechanical stress and bias condition-related changes, ensuring continuous and accurate signal processing across temperature ranges without introducing discontinuities.

Implementation Method 1

The low temperature offset compensation circuit includes first bandgap voltage circuit, and a first base-emitter voltage circuit

Methodology Applied

Scientific EffectBandgap voltage reference:

Implementation Method 2

Current flows through the first bandgap voltage circuit to the first base-emitter voltage circuit

Methodology Applied

Scientific EffectBase-emitter voltage temperature dependence:

Data Source

PatentUS10530308B2Offset drift compensation

Publication Date: 2020.01.07 TEXAS INSTRUMENTS INC

AI summary

An offset drift compensation circuit for correcting offset drift that changes with temperature. In one example, offset drift compensation circuit includes a low temperature offset compensation circuit and a high temperature offset circuit. The low temperature offset compensation circuit is configured to compensate for drift in offset at a first rate below a selected temperature. The high temperature offset compensation circuit is configured to compensate for drift in offset at a second rate above the selected temperature. The first rate is different from the second rate.