TDDI ADC Reuse for Source Driver Safety Detection
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Solution Overview
Problem
Current technologies face challenges in designing safety detection circuits for source driver circuitry within automotive touch display driver integration (TDDI) ICs, as adding dedicated safety detection circuits increases circuit area and may decrease detection accuracy, failing to meet stringent safety standards like ASIL-B for automotive applications.
Innovation Solution
A novel safety detection method utilizing analog-to-digital converters within the touch control circuit of TDDI ICs to monitor source driver circuitry, allowing for safety detection without disrupting normal operation and extending to other analog voltage output circuits, thereby enhancing reliability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated safety detection circuits are added for each source driver channel, then detection accuracy and reliability are improved, but circuit area increases substantially
Solution Approach 1:
The patent makes idle ADC resources perform dual functions: touch sensing during touch periods and safety detection during non-touch periods. This multi-functional use of existing ADCs eliminates the need for separate dedicated safety detection circuits, resolving the contradiction between reliability and circuit area.
Solution Approach 2:
The patent enables existing ADC resources to serve themselves by utilizing their idle time for safety detection functions. The ADCs that would otherwise be dormant during non-touch periods automatically perform safety detection without requiring additional external resources, thus improving reliability without increasing circuit area.
2Area of stationary object
If safety detection circuits are simplified to reduce circuit area, then circuit area is reduced, but detection accuracy decreases
Solution Approach 1:
The patent employs full-precision ADC resources for safety detection by utilizing their idle time, ensuring that detection accuracy is not compromised. The same high-precision ADCs used for touch sensing maintain their full measurement capabilities when performing safety detection, avoiding the accuracy loss that would result from simplified detection circuits.
Solution Approach 2:
The ADC resources perform safety detection using their own inherent high-precision conversion capabilities during idle periods. This self-service approach maintains maximum detection accuracy without requiring additional simplified external detection circuits, thus resolving the contradiction between circuit area and detection accuracy.
3Reliability
If ADC resources are used for safety detection during non-touch periods, then reliability is improved without increasing circuit area, but ADC availability for touch sensing may be affected
Solution Approach 1:
The patent implements time-division multiplexing where ADC resources alternate between touch sensing during touch periods and safety detection during non-touch periods. This periodic switching ensures that touch sensing performance is not affected, as ADC resources are fully available during touch periods while simultaneously enabling safety detection during idle non-touch periods.
Solution Approach 2:
The patent dynamically allocates ADC resources based on operational phases: during touch sensing periods, ADCs are dedicated to touch measurement; during non-touch periods, ADCs dynamically switch to safety detection mode. This dynamic resource allocation ensures optimal performance for both touch sensing and safety detection without mutual interference.
Data Source
AI summary
A touch control circuit for use in a display device includes: a plurality of analog-to-digital converters and a controller. Each of the analog-to-digital converters is coupled to at least one of a plurality of touch sensing electrodes and at least one of a plurality of source drivers of the display device. At least one of the analog-to-digital converters is configured to generate a first measured digital code according to an output voltage outputted by at the least one of the source drivers. The controller is coupled to the analog-to-digital converters, 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 corresponds to, thereby to generate a first safety detection result regarding the at least one of the source drivers.