Universal Input Circuit for AC Current and Voltage Measurement

Solution Overview

Problem

Prior art network analyzers can only measure either AC current or AC voltage on the same pair of input clamps, leading to increased device dimensions and costs due to the need for multiple clamps and processing circuits.

Innovation Solution

An electric quantity measuring device with a switch device and processing unit that can detect the type of signal at the input clamps, allowing both AC current and AC voltage measurements on the same pair of clamps by switching between open and closed configurations, using a single pair of input clamps and processing circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple pairs of clamps and processing circuits are used to measure both AC current and AC voltage, then measurement versatility is improved, but device dimensions and production costs increase

Engineering Contradiction:

Improvemeasurement versatilityVSAvoiddevice dimensions

Core Design Contradiction:

Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The patent implements a universal input circuit that can process both AC current and AC voltage signals through the same pair of clamps. The circuit includes a switching device that can connect the clamps to different processing paths (ADC converter for voltage, current sensor for current) based on the detected signal type, allowing one physical interface to serve multiple measurement functions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs a dynamic switching mechanism that automatically detects the type of signal applied to the input clamps and reconfigures the circuit accordingly. The switching device changes the circuit topology in real-time to match the input signal type, enabling the same hardware to adaptively handle different measurement modes without requiring separate fixed circuits for each function.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If multiple pairs of clamps and processing circuits are used to measure both AC current and AC voltage, then measurement versatility is improved, but production costs increase

Engineering Contradiction:

Improvemeasurement versatilityVSAvoidproduction costs

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent implements a universal input circuit that can process both AC current and AC voltage signals through the same pair of clamps. The circuit includes a switching device that can connect the clamps to different processing paths (ADC converter for voltage, current sensor for current) based on the detected signal type, allowing one physical interface to serve multiple measurement functions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the AC current and AC voltage input circuits into a single shared infrastructure. The same pair of clamps, input terminals, and switching device are used for both measurement types, merging previously separate circuits into one integrated design that reduces component count and simplifies manufacturing.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If multiple pairs of clamps and processing circuits are used to measure both AC current and AC voltage, then measurement versatility is improved, but power consumption increases

Engineering Contradiction:

Improvemeasurement versatilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The patent employs a dynamic switching mechanism that automatically detects the type of signal applied to the input clamps and reconfigures the circuit accordingly. The switching device changes the circuit topology in real-time to match the input signal type, enabling the same hardware to adaptively handle different measurement modes without requiring separate fixed circuits for each function.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements a signal detection and switching sequence that periodically assesses the input signal type and activates only the necessary processing circuit. The microcontroller detects whether AC voltage or AC current is present, then the switching device activates only the relevant path (ADC converter or current sensor), ensuring that power-consuming components are active only when needed rather than continuously.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentEP3392664B1Electric quantity measuring device

Publication Date: 2020.02.12 D E M SRL

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AI summary

The present disclosure relates to an electric quantity measuring device (1) comprising two input clamps (2, 3) adapted to be electrically connected with the output terminals (4, 5) of an electric quantity transducer (6) for receiving an AC current (I) or an AC voltage (V), a processing unit (7) configured to generate at least one electric quantity measuring signal related to the AC current (I) or the AC voltage (V), a switch device (8) comprising an electronic switch (9) comprising two antiserially-connected N-type Mosfet transistors (11,12) and resistive means (10) arranged in series between the two input clamps (2, 3), the electronic switch (9) is configured to switch between closed/open configurations, in which it blocks/allows the passage of current between the two clamps (2, 3), the processing unit (7) detects a potential difference value at the two input clamps (2, 3) and, according to the detected value, causes the electronic switch (9) via a charge pump (13) to switch between the open/closed configurations.