Data Driver Multiplexer With Grayscale-Based Bias Current Control
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Solution Overview
Problem
Display devices, particularly OLEDs, consume significant power due to continuous operation, necessitating a reduction in power consumption.
Innovation Solution
A data driver connects multiple sub-pixels to one output buffer through a multiplexer and adjusts bias current based on grayscale differences, using a power control circuit to vary power consumption according to image data grayscale changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the display device operates continuously to provide information to users, then the display function is maintained, but power consumption increases significantly
Solution Approach 1:
The patent implements dynamic power management by making the display device's operational state changeable between active and standby modes. The controller adjusts system behavior based on user presence detection, transitioning from continuous operation to selective operation, thereby reducing power consumption while maintaining display functionality when needed.
Solution Approach 2:
The system employs periodic user presence detection and alternating between active display mode and standby mode. Instead of continuous operation, the display activates periodically based on detection cycles, creating a rhythmic pattern of operation that reduces overall power consumption while ensuring the display is available when users are present.
2Reliability
If multiple sub-pixels are connected to separate output buffers, then each sub-pixel receives optimal data voltage, but device complexity and power consumption increase
Solution Approach 1:
The patent merges multiple output buffers into a single shared output buffer that serves multiple sub-pixels. The multiplexer dynamically connects the single buffer to different sub-pixels based on which pixel column is currently being driven, eliminating the need for separate buffers for each sub-pixel while maintaining proper data voltage delivery through time-multiplexed access.
Solution Approach 2:
The single output buffer is designed to perform multiple functions by sequentially serving different sub-pixels. Through the multiplexer, one buffer becomes universal, handling data output for various sub-pixels at different time intervals, thereby reducing the total number of buffers needed while maintaining full functionality for each sub-pixel.
3Reliability
If the output buffer operates at full power continuously, then data voltage stability is maintained, but overall power consumption increases
Solution Approach 1:
The output buffer operates in periodic bursts rather than continuously. It activates only during periods when data needs to be driven to the display and enters low-power standby mode during periods when no data transmission is required. This periodic operation maintains data voltage stability when active while dramatically reducing average power consumption.
Solution Approach 2:
The output buffer's operational state is dynamically adjusted between active and standby modes based on real-time data transmission requirements. The buffer transitions from full-power operation during data driving periods to minimal-power operation during idle periods, optimizing the balance between voltage stability and power consumption.
Data Source
AI summary
Discussed is a display device including a display panel having a plurality of sub-pixels, a data driver configured to convert image data input from the outside and provide data voltages to the plurality of sub-pixels through a plurality of data lines, and a multiplexer connected between the data driver and the plurality of data lines. The multiplexer includes a plurality of switching elements controlled by a plurality of mux control signals. The data driver includes a plurality of output buffers configured to amplify and output the data voltage based on a bias current, and controls the bias current supplied to each of the output buffers based on a grayscale difference value of the image data provided to the plurality of sub-pixels.