Single-Path Current Comparator for Multi-Threshold Accuracy

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Solution Overview

Problem

Current comparators face inaccuracies due to replica current mismatches and require a significant number of components, leading to high power consumption and a large integrated circuit footprint.

Innovation Solution

A current comparator design with a single current path that can be reconfigured based on the comparison with a set of current thresholds, reducing component count and power consumption while improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a traditional current comparator design with multiple current paths is used, then it can compare input current to multiple thresholds, but it requires a significant number of components leading to high power consumption and large integrated circuit footprint

Engineering Contradiction:
Improvecurrent comparison accuracyVSAvoidcomponent count
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple current path comparisons into a single current path by sequentially comparing the input current to multiple threshold currents. The switching devices reconfigure the single current path to connect different threshold currents to the comparator input at different times, eliminating the need for multiple parallel current paths and their associated components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs dynamic reconfiguration of the current path using switching devices that change the circuit topology based on the comparison stage. The switching devices enable the single current path to adaptively connect to different threshold currents sequentially, transforming a static multi-path design into a dynamic single-path system.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If a traditional current comparator design with multiple current paths is used, then it can compare input current to multiple thresholds, but it results in high power consumption due to multiple active current paths

Engineering Contradiction:
Improvecurrent comparison accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent merges multiple current path comparisons into a single current path by sequentially comparing the input current to multiple threshold currents. The switching devices reconfigure the single current path to connect different threshold currents to the comparator input at different times, eliminating the need for multiple parallel current paths and their associated components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements periodic sequential comparison by cycling through different threshold currents in a systematic sequence. The switching devices activate different threshold comparisons at different time intervals, allowing the system to perform multiple comparisons using a single active current path at any given moment, thereby reducing continuous power consumption.

Inventive Principle:
Principle #19Periodic action

3Productivity

If replica currents are used for comparison, then multiple threshold comparisons can be performed simultaneously, but inaccuracies arise due to replica current mismatches

Engineering Contradiction:
Improvecomparison speedVSAvoidcomparison accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent extracts the threshold current values from replica current sources and stores them as stored values in memory. Instead of generating replica currents that are prone to mismatch, the system retrieves precise threshold values from storage and uses them programmatically, eliminating the source of replica current mismatch errors.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates digital copies of threshold current values in memory rather than physical replica currents. These stored values are copied and used by the control logic to perform comparisons, providing accurate threshold references without the physical mismatches that occur in analog replica current implementations.

Inventive Principle:
Principle #26Copying

4Productivity

If multiple current paths are used for threshold comparison, then simultaneous comparisons are possible, but the integrated circuit footprint becomes large

Engineering Contradiction:
Improvecomparison capabilityVSAvoidintegrated circuit footprint
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent merges multiple current path comparisons into a single current path by sequentially comparing the input current to multiple threshold currents. The switching devices reconfigure the single current path to connect different threshold currents to the comparator input at different times, eliminating the need for multiple parallel current paths and their associated components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs dynamic reconfiguration of the current path using switching devices that change the circuit topology based on the comparison stage. The switching devices enable the single current path to adaptively connect to different threshold currents sequentially, transforming a static multi-path design into a dynamic single-path system.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3834288B1Apparatus and method for comparing input current to set of current thresholds
Publication Date: 2022.08.31 QUALCOMM INC
  • EP3834288B1 patent drawingFigure 1~2
  • EP3834288B1 patent drawingFigure 3A~3B
  • EP3834288B1 patent drawingFigure 4A~4B

AI summary

A current comparator including a first comparator configured to generate a first output signal based on a comparison of a first current to at least a second current; a second comparator configured to generate a second output signal based on a comparison of the first current to at least a third current; and a circuit configured to: direct the first current to the first comparator to perform the comparison of the first current to the at least the second current while blocking the first current from being applied to the second comparator; or direct the first current to the second comparator to perform the comparison of the first current to the at least the third current while blocking the first current from being applied to the first comparator.