Semiconductor Switch Fracture Sensor for Airbag Safety
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Solution Overview
Problem
Integration of semiconductor switches on a single chip in passenger protection systems, such as airbags and seatbelt pretensioners, can lead to uncontrolled activation due to chip fractures from thermal or mechanical stresses, posing a risk of faulty triggering.
Innovation Solution
A circuit arrangement with a semiconductor chip containing a first switch and a fracture sensor, coupled with an external protective circuit having a second switch that is switched off upon detecting a fracture, preventing the flow of firing current to the firing element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two semiconductor switches are integrated into a common semiconductor chip, then device complexity is reduced and manufacturing is simplified, but reliability deteriorates due to risk of uncontrolled activation from chip fracture
Solution Approach 1:
The invention divides the protection function into two parts: a fracture sensor integrated on the semiconductor chip and a protective circuit implemented externally. This segmentation allows the chip to remain compact while the protective function is distributed to external components, resolving the contradiction between integration benefits and reliability concerns from chip fracture
Solution Approach 2:
The invention introduces an intermediary protective circuit that acts as a mediator between the semiconductor chip and the firing element. This external protective circuit monitors chip integrity through the fracture sensor and controls the firing current, preventing uncontrolled activation while maintaining the integrated chip structure
2Reliability
If a fracture sensor is added to detect chip fractures, then reliability is improved by preventing uncontrolled activation, but device complexity increases due to additional components
Solution Approach 1:
The fracture sensor is merged with the semiconductor chip structure, sharing the same substrate and manufacturing process. This combining approach allows the reliability function to be added without requiring separate discrete components, thereby minimizing the increase in device complexity while improving activation control
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
Prevents uncontrolled activation of passenger protection systems by ensuring the semiconductor switches are switched off in case of a chip fracture, thereby preventing faulty triggering of the firing element.
Implementation Method 1
a fracture sensor... configured such that an on/off state of the second switch is set in accordance with a state of the fracture sensor
Data Source
AI summary
An apparatus for driving a load that may include, for instance, a semiconductor chip, comprising a first switch, and a fracture sensor. The apparatus may further include, for instance, a circuit disposed outside the semiconductor chip and comprising a second switch coupled in series with the first switch, and configured such that an on/off state of the second switch is set in accordance with a state of the fracture sensor.