Position Detecting Device Short-Circuit Protection
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Solution Overview
Problem
Conventional position detecting devices for throttle valves in internal combustion engines cannot detect short-circuiting of output terminals between integrated circuits, leading to potential damage from excessive current flow, as the sum of signal values remains constant even in abnormal conditions.
Innovation Solution
A position detecting device with multiple integrated circuits, each comprising a magnetism detection element, signal processor, and output circuit, including power and ground side transistors, current detectors, and comparator circuits to control voltage and detect abnormal currents, with a cutoff unit to prevent damage by disconnecting the output signal line when abnormal conditions are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If output terminals of two integrated circuits are short-circuited, then an intermediate potential of voltage signals is output to the ECU and the sum of signal values remains constant, but excessive current flows from one integrated circuit into the other, causing potential damage to output circuits
Solution Approach 1:
The patent implements preliminary protective actions by detecting current abnormalities before they cause damage. Current detector circuits continuously monitor the current flowing between integrated circuits, and comparator circuits compare detected current values against reference values to identify short-circuit conditions in advance, triggering cutoff circuits to disconnect the short-circuited output terminals before excessive current can damage the output circuits.
Solution Approach 2:
The patent introduces intermediary protective circuits between the integrated circuits and the ECU. These include current detector circuits that measure current flow, comparator circuits that evaluate current abnormalities, and cutoff circuits that act as intermediaries to disconnect short-circuited output terminals. These intermediary components prevent direct harmful current flow while maintaining system functionality.
2Adaptability or versatility
If conventional position detecting devices use two integrated circuits with positive and negative characteristics, then the sum of signal values is theoretically constant for abnormality detection, but this method cannot detect short-circuiting of output terminals
Solution Approach 1:
The patent replaces the conventional signal-value-based abnormality detection method with a current-based detection method. Instead of relying on the sum of signal values from integrated circuits with positive and negative characteristics, the invention uses current detector circuits to directly measure current flow between integrated circuits, and comparator circuits to detect current abnormalities, enabling direct detection of short-circuit conditions that were previously undetectable.
Solution Approach 2:
The patent changes the detection parameter from signal voltage values to current flow values. By monitoring current abnormalities instead of signal value sums, the system can detect short-circuit conditions. The comparator circuits compare detected current values against reference current values to identify when current flow exceeds normal ranges, providing a new parameter-based approach to abnormality detection.
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
The device effectively protects output circuits from short-circuiting by detecting and managing abnormal current flows, ensuring safe operation and preventing damage, allowing the ECU to control the throttle valve safely even when short-circuits occur.
Implementation Method 1
each of which includes a magnetism detection element that outputs a signal corresponding to a magnetism of a magnetic generation unit disposed in an object to be detected
Data Source
AI summary
A position detecting device has an output circuit, which controls voltages of signal lines connecting a power supply and a ground by a power side transistor and a ground side transistor. An output signal line connects a connection point of the signal lines and an output terminal. A first comparator circuit outputs a signal “1” when a current flowing in the line between the power supply and the connection point is larger than a normal current flowing into the ground from the power supply in a normal state. A second comparator circuit outputs a signal “1” when a current flowing in the line between the connection point and the ground is larger than the normal current. When the signal “1” is output from the first comparator circuit or the second comparator circuit, a cutoff circuit turns off a switch disposed in the output signal line.