Position Sensor IC Short-Circuit Detection via Protective Resistors

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Solution Overview

Problem

Conventional position detecting devices cannot detect short-circuits between output terminals of integrated circuits, as the sum of their output signals is assumed to be fixed, making it impossible to identify abnormal conditions such as short-circuiting.

Innovation Solution

Incorporating first and second integrated circuits with protective resistors and abnormality detection circuits that generate signals based on potential differences across these resistors, allowing for detection of short-circuits and controlling output voltages to prevent further current flow, enabling the detection and management of abnormal conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two integrated circuits are used to detect position with cross output characteristics, then position detection function is achieved, but short-circuit abnormality between output terminals cannot be detected

Engineering Contradiction:

Improveposition detection reliabilityVSAvoidshort-circuit detection difficulty

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

A protective resistor is introduced as an intermediary component between the integrated circuit output terminal and the external circuit. This resistor serves as a mediator that enables abnormality detection by creating a measurable voltage drop under normal operation conditions, while also limiting current during short-circuit events.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback by continuously monitoring the voltage across the protective resistor and comparing it against expected values. The abnormality detection circuit provides feedback signals to the control unit, enabling real-time detection of short-circuit conditions through deviations from normal operational patterns.

Inventive Principle:

Principle #23Feedback

2Productivity

If output terminals are connected directly to electronic control unit, then signal transmission is efficient, but large current flow during short-circuit causes damage

Engineering Contradiction:

Improvesignal transmission efficiencyVSAvoidcurrent flow damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The protective resistor is installed beforehand in series with the output terminal, serving as a cushioning element that limits current flow before any short-circuit condition occurs. This pre-positioned resistor prevents excessive current from reaching the integrated circuit and external circuits, thereby protecting against damage during abnormal conditions.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The protective resistor acts as an intermediary component between the integrated circuit output and the external circuit, mediating current flow to prevent direct short-circuit damage while maintaining normal signal transmission functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If protective resistor is added to limit current, then short-circuit protection is achieved, but device complexity increases

Engineering Contradiction:

Improvecurrent flow controlVSAvoidcircuit complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The protective resistor serves multiple functions simultaneously: it limits current during short-circuit conditions, provides a voltage drop for abnormality detection, and maintains compatibility with existing circuit architecture. This multi-functionality reduces the need for additional separate protection components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The abnormality detection function is merged with the protective resistor functionality, where the same resistor that provides current protection also enables detection through voltage monitoring. This consolidation eliminates the need for separate detection circuits, reducing overall device complexity.

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

Enables the detection of short-circuits between output terminals and prevents large current flow, allowing for the maintenance of normal operation and control of output voltages, thereby ensuring reliable position detection and preventing damage to the device.

Implementation Method 1

a first abnormality detection circuit for outputting a first abnormality detection signal based on a potential difference between both ends of the first protective resistor

Methodology Applied

Scientific EffectOhm's Law: Ohm's Law

Data Source

PatentUS8941399B2Position detecting device

Publication Date: 2015.01.27 DENSO CORP

AI summary

A first integrated circuit includes a first voltage output circuit for outputting a voltage, which proportionally increases in correspondence to an angular position of a throttle valve, a first protective resistor, a first output terminal connected to the first protective resistor, and a first abnormality detection circuit for outputting a first abnormality detection signal based on a voltage produced by the first protective resistor. A second integrated circuit is configured similarly to the first integrated circuit by a second voltage output circuit, a second protective resistor, a second output terminal, and a second abnormality detection circuit.