Parallel Capacitor Charging for Noise-Resistant Electrical Parameter Measurement

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Solution Overview

Problem

Existing measurement methods for electrical parameters like resistance and capacitance ratios face inaccuracies due to noise in the supply voltage, which is introduced by varying voltage levels at different measurement times, leading to reduced precision and the need for additional components to stabilize the power supply.

Innovation Solution

The method involves charging both resistors and capacitors in parallel from a common supply voltage, ensuring a similar or equal starting voltage for all measurements, which cancels out noise and eliminates the need for external components to reduce power supply noise, thereby increasing measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If capacitors are charged sequentially from a common supply voltage at different measurement times, then the measurement arrangement can be simplified, but noise from varying supply voltage levels introduces measurement inaccuracies

Engineering Contradiction:
Improvemeasurement arrangement complexityVSAvoidelectrical parameter measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements periodic charging cycles where capacitors are charged in parallel from a common supply voltage source at regular intervals. This periodic action ensures that all capacitors experience the same supply voltage conditions simultaneously, eliminating noise from voltage variations while maintaining a simplified measurement arrangement without requiring additional voltage stabilization components.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent establishes equipotential conditions by connecting all capacitors to a common supply voltage source during charging phases. This ensures that all capacitors start from the same voltage potential level, eliminating potential differences that would otherwise introduce measurement errors. The common voltage bus creates an equipotential environment that cancels out supply voltage noise across all measurement channels.

Inventive Principle:
Principle #12Equipotentiality

2Measurement precision

If external components are added to stabilize the power supply voltage, then measurement accuracy improves, but device complexity and component count increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement arrangement uses the common supply voltage source itself to provide stabilization for all capacitors simultaneously. By charging all capacitors in parallel from this common source during dedicated charging phases, the system self-stabilizes without requiring external voltage regulation components. The supply voltage serves its dual function of providing both power and reference stability, eliminating the need for additional LDOs, voltage regulators, or filtering components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent merges the voltage supply function with the reference voltage function by using a single common supply voltage source for all capacitors. This consolidation eliminates the need for separate voltage stabilization circuits for each capacitor, reducing component count while maintaining measurement accuracy. The common voltage bus serves multiple functions simultaneously, simplifying the overall device architecture.

Inventive Principle:
Principle #5Merging (Combining)

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 approach reduces or eliminates the impact of power supply noise on measurements, allowing for higher accuracy without additional components, and enables more precise determination of electrical parameters like resistance and capacitance ratios.

Implementation Method 1

A load capacitor CL is connected between the load select switch and the input side of the comparator and, further, to the reference potential

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The load capacitor CL is charged with the supply voltage VL and then discharged through one of the resistors R1, R2

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3438677B1Method for determining an electrical parameter and measurement arrangement for determining an electrical parameter
Publication Date: 2024.07.10 SCIOSENSE BV
  • EP3438677B1 patent drawingFigure 1~2
  • EP3438677B1 patent drawingFigure 3~4
  • EP3438677B1 patent drawing

AI summary

A method for determining an electrical parameter comprises charging, in parallel, a first and a second capacitor (CL1, CL2) from a common supply voltage (VL). Then, a first discharge time (t11) is determined by discharging the first capacitor (C1). Furthermore, a second discharge time (t12) is determined by discharging the first capacitor (C1) a second time or by discharging the second capacitor (C2). Finally, the electrical parameter is determined from a ratio of the first and the second discharge times (t11, t12).