Current Detection Device Shunt Resistor Amplifier Circuit

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Solution Overview

Problem

Current detection devices face challenges in increasing detection accuracy without using multiple power supplies with different voltages, which complicates their design and operation.

Innovation Solution

A current detection device comprising a shunt resistor, an insulation circuit that converts voltage into a differential voltage, a differential amplifier circuit, and a constant current circuit that adjusts the output voltage range, allowing for enhanced detection accuracy without requiring multiple power supplies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple power supplies with different voltages are used to expand the output voltage range of the operational amplifier, then detection accuracy of the current is enhanced, but device complexity increases

Engineering Contradiction:
Improvedetection accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameter of the operational amplifier's power supply voltage dynamically. Instead of using multiple fixed power supplies with different voltages, a single power supply's voltage is adjusted according to the input signal characteristics. This allows the output voltage range to be expanded adaptively, improving detection accuracy while avoiding the complexity of multiple power supply circuits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic adjustment of the power supply voltage to the operational amplifier. The power supply voltage is made variable rather than fixed, allowing it to adapt to different measurement conditions. This dynamic approach enables the system to achieve enhanced detection accuracy without requiring multiple static power supply configurations, thereby reducing device complexity.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If multiple power supplies with different voltages are disposed to enhance detection accuracy, then output voltage range is expanded, but the number of components increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent makes a single power supply perform multiple functions by enabling its voltage to be adjusted dynamically. Instead of having separate power supplies for different voltage requirements, one universal power supply with variable voltage output serves all needs. This reduces the quantity of components while maintaining the capability to provide appropriate voltage levels for enhanced detection accuracy.

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

Solution Approach 2:

The patent changes the voltage parameter of a single power supply to achieve what would otherwise require multiple power supplies with fixed different voltages. By adjusting the voltage parameter dynamically, the system reduces the number of power supply components needed while still expanding the output voltage range for improved detection accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4160225B1Electric current detection device and electric current detection method
Publication Date: 2025.01.15 NISSAN MOTOR CO LTD
  • EP4160225B1 patent drawingFigure 1
  • EP4160225B1 patent drawingFigure 2
  • EP4160225B1 patent drawingFigure 3

AI summary

A current detection device (100) includes a shunt resistor (1) connected in series to a path through which a current flows; a first circuit (2) that converts a voltage across the shunt resistor (1) into a predetermined differential voltage; a second circuit (3) to which the predetermined differential voltage is input from the first circuit (2) via a pair of wirings (55) and that amplifies the predetermined differential voltage; a constant current circuit (4) connected between the pair of wirings (55); and an arithmetic circuit (5) that operates the current flowing through the path based on the voltage amplified by the second circuit (3).