Data Driver Switch Unit for OLED Slew Rate and Power
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Solution Overview
Problem
The slew rate of output buffers in data drivers for flat panel displays, particularly organic light emitting displays, is limited by bias currents and compensation capacitors, making it difficult to reduce power consumption and IC size as panel sizes increase.
Innovation Solution
A switch unit is introduced between the output terminals of output buffers and data lines, allowing the application of a middle voltage before data signal output, which improves the slew rate and reduces power consumption by coupling the output terminals to receive the middle voltage, thereby enhancing the performance of the output buffer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the slew rate of the output buffer is reduced to decrease power consumption, then power consumption decreases, but the bias current and compensation capacitor parameters limit how much the slew rate can be reduced
Solution Approach 1:
The patent applies preliminary action by pre-charging the output terminal of the output buffer to a middle voltage level before the actual data signal is output. This is achieved through a switch unit that connects the output terminal to a middle voltage source in advance, preparing the output node to be closer to the eventual output voltage level, thereby reducing the voltage swing required during data output and reducing power consumption without being limited by bias current and compensation capacitor parameters
2Area of stationary object
If the panel size is increased to meet modern display requirements, then display area increases, but the input time increases and the driver IC size increases
Solution Approach 1:
The patent applies parameter changes by modifying the voltage level parameter at the output terminal through the switch unit. By changing the output terminal voltage to a middle voltage level before data output, the effective voltage swing is reduced, which allows for faster charging/discharging of the output capacitance and reduces the input time requirement, thereby enabling larger panel sizes without proportionally increasing input time
3Ease of manufacture
If the driver IC size is reduced to lower costs, then manufacturing cost decreases, but the slew rate control capability is limited
Solution Approach 1:
The patent introduces an intermediary element - the switch unit - that mediates between the output buffer and the data lines. This switch unit provides the middle voltage connection functionality without requiring complex slew rate control circuits, enabling slew rate optimization through a simple voltage selection mechanism rather than complex current or capacitor control, thereby reducing IC size and manufacturing cost while maintaining effective slew rate control
Data Source
AI summary
A data driver and an organic light emitting display having the same. The data driver has a switch unit provided between output terminals of respective output buffers that are provided in the data driver and data lines corresponding thereto. Here, the switch unit is also coupled to a source for providing a middle voltage, and allows the output terminals of the output buffers to be coupled to receive the middle voltage before data signals are output from the data driver by the operation of the switch unit, making it possible to improve the slew rate of the output buffer and to reduce power consumption, and an organic light emitting display having the same. The switch unit may includes a first switch coupled between the source for providing the middle voltage and the output terminals, and a second switch coupled between the output terminals and the respective data lines.