Source Driver Gradation Voltage Fault Detection During Display Blanking
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Solution Overview
Problem
Existing source drivers in in-vehicle display devices lack a fault detection mechanism for the gradation voltage generating circuit, which is crucial for ensuring high reliability and safety in display apparatuses.
Innovation Solution
Incorporation of a gradation voltage determination circuit with a resistor voltage dividing circuit, timing control circuit, selection circuit, detection circuit, and fault detection circuit to monitor and detect faults in the gradation voltage generating circuit, allowing for fault detection during blank periods without affecting normal display operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fault detection function is added to the gradation voltage generating circuit, then reliability is improved, but device complexity increases
Solution Approach 1:
The fault detection function is merged with the existing gradation voltage generating circuit by utilizing the same resistor voltage dividing circuit for both voltage generation and fault detection. The detection circuit is integrated into the existing circuit architecture, sharing components where possible to minimize overall complexity increase.
Solution Approach 2:
A detection circuit is introduced as an intermediary component that monitors the output voltages without disrupting the normal operation of the gradation voltage generating circuit. This intermediary detection mechanism enables fault detection while maintaining the original circuit's functionality.
2Reliability
If continuous monitoring of output voltages is performed, then reliability is improved, but energy consumption increases
Solution Approach 1:
The fault detection circuit performs periodic monitoring of the output voltages during the blank period of the display refresh cycle, rather than continuous monitoring. This periodic action reduces energy consumption while still providing effective fault detection coverage.
Solution Approach 2:
The detection circuit is designed to perform voltage level checks during the blank period before the next display frame begins, ensuring that any faults are detected in advance before they can affect display output. This preliminary detection approach maintains reliability while minimizing energy usage during active display periods.
3Reliability
If fault detection is implemented during active display period, then reliability is improved, but display performance deteriorates
Solution Approach 1:
The fault detection operation is scheduled to occur during the blank period between display frames, utilizing otherwise idle time. This periodic timing ensures that detection activities do not interfere with the active display period and maintain display performance.
Solution Approach 2:
The detection circuit maintains readiness to detect faults continuously, but actual measurement and comparison operations are performed during blank periods. This approach ensures continuous monitoring capability while keeping the display operation uninterrupted and high-performance during active periods.
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
Enables reliable fault detection and monitoring of characteristic variations in the gradation voltage generating circuit, enhancing safety and reliability of in-vehicle display devices by identifying anomalies and preventing potential malfunctions.
Implementation Method 1
a resistor voltage dividing circuit with a plurality of output terminals. The plurality of output terminals output respective reference voltages divided according to gamma curve characteristics
Implementation Method 2
The gradation voltage determination circuit measures an electric potential difference between one pair among the plurality of output terminals and determines whether or not the electric potential difference corresponds to a reference voltage group
Data Source
AI summary
A source driver of the disclosure supplies a display device having a plurality of display cells with gradation voltages corresponding to respective luminance levels for the display cells indicated by a video signal. The source driver includes a gamma voltage generating circuit and a gradation voltage determination circuit. The gamma voltage generating circuit includes a resistor voltage dividing circuit with a plurality of output terminals. The plurality of output terminals output respective reference voltages divided according to gamma curve characteristics for generating the gradation voltages. The gradation voltage determination circuit measures an electric potential difference between one pair among the plurality of output terminals and determines whether or not the electric potential difference corresponds to a reference voltage group based on the gamma curve characteristics.