Display Driver Link Using DC-Balanced Coding Across AC Coupling
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Solution Overview
Problem
Existing display devices face challenges in maintaining stable communication between the timing controller and the source driver due to differences in common mode voltages, leading to errors in low-speed communication signals when using alternating current coupling capacitors.
Innovation Solution
Implementing a communication system with alternating current coupling capacitors that uses direct current balance codes, such as Manchester or 8B10B codes, to encode low-speed communication signals, ensuring balanced voltage levels and minimizing errors by encoding preamble signals to facilitate smooth transitions to high-speed communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If AC coupling capacitors are used to minimize DC elements and remove common mode voltage differences, then high-speed communication capability is improved, but low-speed communication signal processing becomes unreliable
Solution Approach 1:
The patent applies preliminary action by performing low-speed communication first to establish common mode voltage levels and synchronize clocks before transitioning to high-speed communication. This preparatory phase ensures that the AC coupling capacitors are properly charged and the voltage levels are stabilized, preventing signal perception errors in subsequent high-speed communication.
Solution Approach 2:
The patent uses periodic action by alternating between low-speed communication phases (for voltage level synchronization and clock training) and high-speed communication phases (for data transmission). This periodic switching allows the system to maintain reliable signal perception across both speed regimes by regularly resetting and synchronizing the communication parameters.
2Device complexity
If general codes like NRZ are used for encoding communication signals, then encoding simplicity is improved, but low-speed communication signal perception fails when identical bits continue
Solution Approach 1:
The patent applies parameter changes by switching between different encoding schemes based on communication speed requirements. For low-speed communication, it uses encoding methods that ensure voltage level transitions (such as Manchester encoding or 8b/10b encoding) to prevent DC drift and ensure reliable signal perception. For high-speed communication, it transitions to more efficient encoding schemes. This dynamic parameter adjustment resolves the contradiction between encoding simplicity and signal perception reliability.
3Productivity
If communication lines use AC coupling capacitors for high-speed communication, then data transmission rate is improved, but common mode voltage level differences cause signal transmission errors
Solution Approach 1:
The patent applies preliminary action by performing a voltage level synchronization phase before high-speed data transmission. During this preliminary phase, the timing controller and source driver establish matching common mode voltage levels through low-speed communication, ensuring that when AC coupling capacitors are used for high-speed transmission, no voltage level mismatches cause signal errors.
Solution Approach 2:
The patent uses feedback mechanisms where the source driver monitors received signal quality and adjusts its internal voltage levels accordingly. The timing controller also adjusts its output voltage levels based on feedback from the source driver about signal reception status. This closed-loop feedback ensures that common mode voltage levels remain synchronized even when AC coupling capacitors are present in the communication path.
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
The solution enables reliable low-speed communication with reduced errors and seamless transition to high-speed communication, improving data processing efficiency in display devices.
Implementation Method 1
If 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
A method for transmitting data by a first integrated circuit, can include encoding a first protocol signal including a configuration data using a direct current (DC) balance code, transmitting the encoded first protocol signal including the configuration data, at a first transmission rate, to a second integrated circuit, and transmitting a second protocol signal, at a second transmission rate higher than the first transmission rate, to the second integrated circuit. The encoded first protocol signal includes a bit or a symbol disposed before and after the configuration data.