Built-in Self-Test Circuit for Automotive Backup Battery Reliability
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Solution Overview
Problem
Airbag supplemental restraint systems face challenges in maintaining electrical integrity, particularly in ensuring that airbags deploy correctly during collisions while avoiding accidental deployments due to issues like short circuits or power disruptions in automotive safety applications.
Innovation Solution
A system incorporating a switching regulator and an electrochemical storage test circuit with a built-in self-test (BIST) mechanism, which includes a bidirectional switch and a BIST circuit to monitor and ensure the proper functioning of a backup battery, ensuring power is supplied to airbag squibs during emergencies and performing self-tests to maintain system reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors are used to maintain high safety integrity level, then the reliability of airbag deployment is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple sensing functions (pressure sensing and acceleration sensing) into a coordinated system that shares common processing and control resources through the microcontroller, reducing overall system complexity while maintaining the reliability benefits of multiple sensors
Solution Approach 2:
The microcontroller serves multiple functions including coordinating the sensing elements, processing signals from both pressure sensors and accelerometers, controlling airbag deployment, and managing system diagnostics, thereby reducing the need for separate dedicated circuits for each function
2Reliability
If additional monitoring and test circuits are added to detect electrical integrity issues, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The system incorporates self-diagnostic capabilities where the microcontroller continuously monitors the electrical integrity of connected circuits and components, including the backup battery system, allowing the system to detect and report faults without requiring external testing equipment
Solution Approach 2:
The patent implements feedback mechanisms through the microcontroller that continuously monitor the state of sensing elements, actuators, and power supply systems, providing real-time information about system health and enabling proactive fault detection and reporting
3Reliability
If a backup battery system is implemented to ensure power supply during emergencies, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent integrates the backup battery system with the main power supply architecture, using shared voltage regulation and distribution circuits that serve both the primary and backup power sources, thereby reducing the need for completely separate power management subsystems
Solution Approach 2:
The voltage regulator and power management circuits act as intermediaries that seamlessly manage power flow between the main battery, backup battery, and various system components, automatically switching between power sources as needed without requiring complex control logic
Data Source
AI summary
According to an embodiment, a system includes a switching regulator and an electrochemical storage test circuit. The switching regulator is coupled to a power supply input and configured to supply a regulated voltage to a regulated supply terminal that is configured to be coupled to a device. The electrochemical storage test circuit is configured to be coupled to an electrochemical storage unit. The electrochemical storage test circuit includes a bidirectional switch with a first switch terminal coupled to the regulated supply terminal, a second switch terminal configured to be coupled to the electrochemical storage unit, and a switch control terminal. The electrochemical storage test circuit also includes a built-in self-test (BIST) circuit configured to be coupled to the electrochemical storage unit and to the switch control terminal.