TDDI ADC Safety Detection for Automotive Source Drivers
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Solution Overview
Problem
Current technologies face challenges in designing safety detection circuits for source driver circuitry within automotive TDDI ICs, leading to potential errors and failure to meet ASIL-B safety standards due to the high number of channels, which complicates the design and increases circuit area, and simplifying these circuits may compromise detection accuracy.
Innovation Solution
A novel safety detection method utilizing analog-to-digital converters (ADCs) in the touch control circuit to monitor source driver and other analog circuitry output voltages during non-touch sensing periods, ensuring reliability without disrupting normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated safety detection circuits are added for each channel of source driver circuitry, then detection accuracy and safety compliance are improved, but circuit area increases substantially
Solution Approach 1:
The patent makes idle ADCs perform dual functions: their primary function during touch sensing and an additional safety detection function during non-sensing periods. This multi-functionality allows safety detection without adding dedicated detection circuits, resolving the contradiction between reliability improvement and area increase.
Solution Approach 2:
The system uses its own existing resources (idle ADCs and non-sensing time periods) to perform safety detection. Rather than adding external detection components, the system serves its own safety monitoring needs using internally available capabilities, avoiding area increase while maintaining detection accuracy.
2Area of stationary object
If safety detection circuits are simplified to reduce circuit area, then area is reduced, but detection accuracy decreases
Solution Approach 1:
The system uses its own existing high-precision ADCs for safety detection rather than adding simplified detection circuits. This self-service approach maintains detection accuracy by leveraging the full capability of existing conversion resources without requiring additional dedicated detection hardware.
Solution Approach 2:
Existing ADCs are made multi-functional, serving both touch sensing conversion and safety detection conversion. This eliminates the need for separate simplified detection circuits while preserving the high measurement precision of the original ADCs for safety monitoring purposes.
3Reliability
If ADCs are used for safety detection during non-touch sensing periods, then reliability is improved without disrupting normal operation, but additional processing time is required
Solution Approach 1:
Safety detection is performed periodically during non-touch sensing periods rather than continuously. This periodic execution allows the system to maintain high reliability through regular monitoring while utilizing otherwise idle time periods, thus avoiding disruption to normal touch sensing operations and minimizing additional processing time impact.
Solution Approach 2:
The ADCs continue to perform useful work during non-sensing periods by conducting safety detection, rather than remaining completely idle. This continuous utilization of conversion resources for safety monitoring improves reliability without requiring separate dedicated detection hardware or extending overall system operation time.
Data Source
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AI summary
A touch control circuit (100) for use in a display device (10) includes: analog-to-digital converters (120_1-120_K) and a controller (130). Each of the analog-to-digital converters (120_1-120_K) is coupled to at least one of touch sensing electrodes (TS0-TST) and at least one of source drivers (230_1-230_N) of the display device (10). At least one of the analog-to-digital converters (120_1-120_K) is configured to generate a first measured digital code according to an output voltage outputted by at the least one of the source drivers (230_1-230_N). The controller (130) is and configured to compare the first measured digital code with an input digital code that the output voltage of the at the least one of the source drivers (230_1-230_N) corresponds to, thereby to generate a first safety detection result regarding the at least one of the source drivers (230_1-230_N).