Sensor Fault Detection IC Level Shifting High Voltage Signals
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Solution Overview
Problem
Current fault detection systems for transducers in automotive applications require external devices operating in a high voltage domain, increasing complexity, cost, and power consumption, and often operate in a non-linear manner, necessitating additional signal conditioning to detect faults across varying supply potentials.
Innovation Solution
A sensor control IC with integrated fault detection system that level shifts sensor supply line signals from a first voltage domain to a second domain, allowing for fault detection within the controller IC's voltage domain, using fault detector circuits and comparators to identify shorts and open connections, and communicates fault status indicators to an external processor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external fault detection devices operating in the first voltage domain are used, then faults on microphone supply lines can be detected, but device complexity, cost, and power consumption increase
Solution Approach 1:
The patent merges the fault detection function with the audio control IC by integrating a level shifter and comparator circuit directly into the IC. This eliminates the need for separate external fault detection devices, reducing system complexity while maintaining the ability to detect faults on microphone supply lines operating at high voltages (1V-7V). The integrated circuit now performs both audio control and fault detection functions.
Solution Approach 2:
The patent introduces a level shifter as an intermediary component within the integrated circuit that bridges the voltage domain gap between the high voltage microphone supply lines (1V-7V) and the low voltage audio control IC operating domain (3V-5V). This level shifter enables the IC to safely monitor high voltage supply lines without exposing its internal circuitry to damaging voltage levels.
2Reliability
If external fault detection devices operating in the first voltage domain are used, then faults can be detected, but power consumption increases
Solution Approach 1:
By combining the fault detection circuitry with the audio control IC, the patent eliminates the need for separate powered external devices. The fault detection function shares the power supply and operational context with the existing audio control IC, thereby reducing overall system power consumption while maintaining effective fault monitoring.
3Reliability
If external fault detection devices are used, then fault detection is possible, but additional signal conditioning is required due to non-linear operation
Solution Approach 1:
The level shifter circuit within the integrated fault detection system serves as an intermediary that linearizes and conditions the voltage signals from the high voltage domain before they are processed by the comparator. This internal signal conditioning eliminates the need for external signal conditioning equipment, reducing system complexity while ensuring accurate fault detection across varying supply potentials.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the reference voltage levels in the comparator based on the actual supply potential of the microphone circuit. This allows the fault detection system to adapt to varying voltage conditions (1V-7V) without requiring complex external signal conditioning, as the internal comparator automatically adjusts its threshold to detect faults across the full voltage range.
Data Source
AI summary
Fault detection techniques for control of sensor systems. A sensor control integrated circuit (“IC”) may include a fault detection system for coupling to the sensor supply lines. The system may detect faults for each of the sensor supply lines. The fault detection system may level shift sensor supply line signals from a first voltage domain to a second voltage domain appropriate for the fault detection system of the controller IC. The fault detection system may level shift source potential voltages from the first voltage domain to the second voltage domain to detect predetermined fault types. The fault detection system may compare the second domain voltages from the sensor supply lines to voltages representing predetermined fault types and may generate fault status indicators based on the comparison.