Clip-on Ammeter USB Power and Digital Data Interface

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Solution Overview

Problem

Current clamp meters are not universally compatible with oscilloscopes, require separate energy supplies, and are expensive, with those without energy supplies limited to measuring alternating currents only, leading to inaccurate direct current measurements due to unstable voltage references.

Innovation Solution

A clamp meter design featuring a current detection unit, evaluation unit, and USB interface that provides digital data and power via USB, using a voltage converter for stabilized voltage to enable precise direct current measurement without additional energy sources, allowing universal connectivity and cost-effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a current clamp uses a separate power supply (battery or external), then it can measure both alternating and direct currents with stable reference voltage, but it increases device complexity and cost

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidpower supply requirement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The current clamp uses the USB interface to draw power from the connected external device (oscilloscope, PC, etc.) to supply the evaluation unit and voltage reference, eliminating the need for a separate battery or power supply. The system serves itself by using the host device's power to maintain stable voltage reference for accurate DC and AC current measurements.

Inventive Principle:
Principle #25Self-service

2Device complexity

If a current clamp is designed without a separate power supply, then it reduces device complexity and cost, but it can only measure alternating currents due to unstable reference voltage

Engineering Contradiction:
Improvepower supply structureVSAvoiddirect current measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The USB interface acts as an intermediary that provides both power and stable voltage reference from the host device to the current clamp's evaluation unit. This mediator enables the system to achieve stable DC current measurements without requiring an internal battery or separate power supply, thus maintaining simplicity while ensuring measurement accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If a current clamp uses device-specific connector systems for power supply, then it can be powered by the oscilloscope, but it loses universal compatibility with different oscilloscopes

Engineering Contradiction:
Improvepower supply capabilityVSAvoidoscilloscope compatibility
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The current clamp uses a universal USB interface for both data transmission and power supply, replacing device-specific connector systems. This universal interface enables the current clamp to be compatible with any USB-capable device (oscilloscopes, PCs, laptops, etc.), providing both power and data communication through a single standardized connection, thus achieving multi-functionality and broad adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If a current clamp uses USB interface for power and data, then it achieves universal compatibility and eliminates separate power sources, but it requires stable USB voltage for accurate measurements

Engineering Contradiction:
Improveuniversal compatibilityVSAvoidmeasurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The evaluation unit processes the USB supply voltage (typically 5V) and transforms it into a stable, precise voltage reference suitable for accurate current measurements. By changing the voltage parameters through regulation and reference generation, the system maintains measurement accuracy despite variations in USB power supply characteristics across different host devices.

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

Enables precise recording of both alternating and direct currents with high accuracy, eliminating the need for separate power sources and providing universal compatibility, reducing costs and environmental impact.

Implementation Method 1

an indirect measurement of the current is carried out, in particular by detecting a static or changing magnetic field forming around an electrical conductor

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

The current detection unit is designed, for example, as a Hall sensor

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3191852B1Clip-on ammeter
Publication Date: 2024.03.06 INFINEON TECHNOLOGIES AG
  • EP3191852B1 patent drawingFigure 1
  • EP3191852B1 patent drawingFigure 2
  • EP3191852B1 patent drawingFigure 3

AI summary

The invention relates to a clip-on ammeter comprising a current detection unit (1), an evaluation unit (2) and a USB interface (3). The current detection unit (1) makes it possible to detect current values and make the current values available as measured values; the evaluation unit (2) includes an analog to digital converter and is connected to the current detection unit (1); the evaluation unit (2) allows the measured values to be transmitted in a processable manner as USB-compatible digital data to the USB interface (3); and the USB interface (3) is connected to the evaluation unit (2) and allows the USB-compatible data to be made available in a transmissible manner for further processing. The evaluation unit (2) can be energized using the USB interface (3). The clip-on ammeter further comprises a voltage transformer (9) that can be energized by the USB interface (3), the voltage transformer (9) making it possible to supply a stabilized voltage as reference voltage for the current detection unit.