Display Data Driver Encoding for AC-Coupled Low-Speed Signals
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Solution Overview
Problem
Existing display devices face challenges in smoothly processing low-speed communication signals due to the use of general codes like NRZ codes, which can lead to abnormal perception of data bits, especially when there are long sequences of identical data bits.
Innovation Solution
The implementation of a system that uses a communication line with an AC coupling capacitor, where low-speed communication signals are encoded using a DC balance code such as the Manchester code or 8B10B code, to minimize communication errors and ensure correct data perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an AC coupling capacitor is connected to the communication line to enable high-speed communication, then the communication speed is improved, but the source driver cannot smoothly process low-speed communication signals encoded using general codes
Solution Approach 1:
The patent changes the encoding parameter from general codes (like NRZ) to DC balance codes (like Manchester or 8B10B codes). This parameter change ensures that the transmitted signals have balanced DC components, which are compatible with AC coupling capacitors. The DC balance code maintains equal numbers of high and low voltage levels over a complete code cycle, preventing DC blocking by the capacitor and ensuring reliable data perception at both low and high speeds.
2Device complexity
If a general code like NRZ code is used for encoding, then the encoding is simple, but the source driver may not perceive data bits correctly when there are long sequences of identical data bits
Solution Approach 1:
The DC balance code introduces periodic transitions in the signal pattern. For example, Manchester code transitions at the middle of each bit period, and 8B10B code ensures periodic voltage level changes every 10 bits. This periodic action prevents long sequences of identical voltage levels, ensuring that the source driver can continuously detect signal transitions and correctly perceive data bits even when the data contains long runs of identical values.
3Speed
If the communication line uses AC coupling capacitor for high-speed communication, then the DC element is minimized, but low-speed communication signals with long identical data bit sequences cannot be processed smoothly
Solution Approach 1:
The patent changes the signal encoding parameter to DC balance codes that inherently provide balanced voltage levels. This parameter change makes the low-speed communication signals compatible with AC coupling capacitors, as the balanced DC components prevent capacitor blocking. The encoding ensures that over complete code cycles, the number of high and low voltage levels are equal, allowing smooth processing of low-speed signals while maintaining high-speed communication capability.
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
This approach allows for reliable low-speed communication in display devices by reducing transmission errors caused by AC coupling capacitors, ensuring accurate data perception and minimizing data loss rates.
Implementation Method 1
an alternating current coupling capacitor (AC coupling capacitor) is connected to a communication line, it is possible to minimize a direct current (DC) element in a signal transmitted from the timing controller
Data Source
AI summary
The present disclosure relates to a data driving device, a data processing device, and a system for driving a display device and, more particularly, it relates to a data driving device, a data processing device, and a system for smoothly performing a low-speed communication through a communication line including an alternating current coupling capacitor.