Solid-State Power Switch Self-Test for Overload Fault Detection
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Solution Overview
Problem
Existing smart power switches in autonomous driving vehicles lack the necessary reliability to prevent failures such as short-circuits and overloads, which can compromise the operation of critical components like radars and cameras.
Innovation Solution
A solid state power switch device with a built-in self-test module that includes a switch control unit, current measurement module, reference signal module, and comparator module to detect and respond to abnormal current levels, triggering the switch to open in case of overload or short-circuit, and a diagnostic unit to report test results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing smart power switches rely on switch element behavior as smart fuse, then device complexity is reduced, but reliability is insufficient for autonomous driving vehicles
Solution Approach 1:
The power management device performs self-diagnostics automatically without external intervention. The control unit executes test sequences that activate switch elements, measure current through shunt resistors, and detect failures autonomously, allowing the system to monitor and report its own health status continuously
Solution Approach 2:
The system performs preliminary diagnostic tests by applying control signals to switch elements before actual operation to detect potential failures. Test sequences are executed periodically or continuously to identify open circuit or short circuit conditions before they affect normal vehicle operation
2Difficulty of detecting and measuring
If no self-test function is implemented, then device complexity is low, but failure detection capability is insufficient
Solution Approach 1:
The control unit continuously monitors current through shunt resistors during switch element operation and compares measured values against expected ranges. This feedback mechanism enables real-time detection of abnormal conditions such as open circuit or short circuit failures, triggering appropriate error responses
Solution Approach 2:
Shunt resistors are introduced as intermediary components to enable current measurement during self-diagnostics. These resistors allow the control unit to indirectly detect switch element status by measuring voltage drops, providing a safe and accurate method for failure detection without directly accessing high-current paths
3Reliability
If continuous monitoring of all switch elements is performed, then reliability is improved, but energy consumption increases
Solution Approach 1:
The control unit performs self-diagnostics periodically or continuously at controlled intervals rather than maintaining constant monitoring of all switch elements. Test sequences are executed at appropriate moments to balance reliability requirements with energy conservation, reducing power consumption during normal operation while maintaining safety
Data Source
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AI summary
A solid state power switch device (10) comprises a switch unit (16) comprising at least one switch element (22) configured to provide power supply to a load (12) of a vehicle (14) while the switch element (22) is in close state; a switch control unit (18) in communication with the switch unit (16), and configured to control in open/close state the switch element (22); the switch control unit (18) comprising a built in self-test module (46) of the switch element (22) configured to control a self-test sequence of the switch element (22) and to check failure/success of the self-test sequence of the switch element (22) such that the switch unit (16) is self-tested.