Load Control Backup Signal Circuit for Microcomputer Failure
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Solution Overview
Problem
Existing load control systems in vehicles face challenges in maintaining normal operation when microcomputers experience failures, either due to electromagnetic noise, program defects, or faulty output ports, leading to uncontrollable load energization and difficulty in identifying normal output function states.
Innovation Solution
A load control backup signal generating circuit that monitors constant period and control signals for abnormal conditions, generating a backup control signal to ensure load control even during microcomputer failures, using a combination of timer circuits, latch circuits, and clearing circuits to identify and respond to signal abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a microcomputer is used for load control, then control functionality is improved, but reliability deteriorates due to potential failures from electromagnetic noise, program defects, or faulty output ports
Solution Approach 1:
The patent implements a backup control signal generating circuit that is pre-configured and ready to activate when the microcomputer fails. This backup circuit includes a timer that continuously monitors for abnormal conditions and automatically generates backup control signals without requiring microcomputer operation, ensuring continuous load control capability.
Solution Approach 2:
The patent applies different operational modes to different parts of the control system. The microcomputer operates in normal mode for standard control tasks, while the backup circuit operates in standby mode and activates locally when specific failure conditions are detected, providing targeted reliability enhancement without compromising overall control functionality.
2Reliability
If a backup control signal generating circuit is added, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the backup control signal generating circuit with the existing microcomputer control system, integrating the timer and backup signal generation functionality into the overall control architecture. This merging approach allows the backup circuit to share power supply, signal lines, and control pathways with the main system, reducing the additional complexity that would arise from completely separate backup infrastructure.
Data Source
AI summary
A load control backup signal generating circuit for supplying a backup control signal to a switch of a load connected to an output of a control processor in a case that abnormality occurs in the control processor, includes a first input terminal that receives a constant period signal that is output periodically from the control processor when the control processor is normal, a constant period signal monitoring section that monitors a state of the constant period signal for identifying whether a length of the time during which a high or low level state of the constant period signal continues is longer than a predetermined time, and that outputs the signal corresponding to a result of the identification, and a backup signal output section that outputs the backup control signal when the output of the constant period signal monitoring section satisfies a predetermined condition.