Adaptive Voltage Control for Electroluminescent Display Power Supply

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Solution Overview

Problem

Electroluminescent displays face challenges in reducing power consumption while maintaining display quality, as controlling power supply voltage based on image brightness analysis can lead to degradation in brightness ratio and driving current coincidence with colors, and predicting precise ohmic drop is difficult.

Innovation Solution

The implementation of an adaptive voltage controller that detects ohmic drop using feedback voltage and adjusts the low power supply voltage based on the detected ohmic drop, utilizing an analog-to-digital converter, voltage converter, and adaptive voltage controller to generate a voltage control signal that varies depending on image data and ohmic drop, ensuring the power supply voltage is maintained at a target voltage that balances grayscale and ohmic drop margins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the low power supply voltage is lowered to reduce power consumption, then power consumption is reduced, but the driving current and brightness ratio deteriorate due to ohmic drop

Engineering Contradiction:
Improvepower consumptionVSAvoiddriving current coincidence with colors
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the ohmic drop of the low power supply voltage is detected through feedback voltages generated by the display panel. The adaptive voltage controller uses this detected ohmic drop information to dynamically adjust the low power supply voltage, ensuring that the driving current maintains proper coincidence with color characteristics while optimizing power consumption.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent makes the low power supply voltage dynamic rather than fixed. The adaptive voltage controller continuously adjusts the voltage level based on detected ohmic drop and image data characteristics, allowing the system to adapt to varying operating conditions and maintain optimal performance across different display scenarios.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If the low power supply voltage is adaptively controlled based on image brightness, then power consumption is reduced, but display quality degrades due to inaccurate ohmic drop prediction

Engineering Contradiction:
Improvepower consumptionVSAvoidohmic drop detection accuracy
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent replaces predictive methods with direct feedback measurement. Feedback voltages are generated based on the actual ohmic drop occurring in the display panel, providing accurate real-time information about voltage losses. This feedback mechanism eliminates the need for inaccurate predictions and enables precise adaptive voltage control.

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If the low power supply voltage is reduced to improve power efficiency, then power consumption decreases, but grayscale margin and display quality are compromised

Engineering Contradiction:
Improvepower consumptionVSAvoidgrayscale margin
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent dynamically adjusts the low power supply voltage based on detected ohmic drop and image data characteristics, allowing the system to maintain adequate grayscale margins when needed while reducing voltage (and power consumption) when conditions permit. This dynamic approach prevents fixed voltage reduction from compromising display quality.

Inventive Principle:
Principle #15Dynamics

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 reduces power consumption while suppressing degradation of display quality by accurately controlling the low power supply voltage, ensuring efficient power management without compromising image quality.

Implementation Method 1

the display panel is configured to generate at least one feedback voltage corresponding to an ohmic drop of the first power supply voltage

Methodology Applied
Scientific EffectOhmic drop: Electrical Resistance

Implementation Method 2

the electroluminescent display can be driven with quick response speed and reduced power consumption, using a matrix of light-emitting diodes (LEDs) or an organic light-emitting diodes (OLEDs) that emit light through recombination of electrons and holes

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3038087B1Electroluminescent display and method of driving the same
Publication Date: 2019.10.09 SAMSUNG DISPLAY CO LTD
  • EP3038087B1 patent drawingFigure 1
  • EP3038087B1 patent drawingFigure 2~3
  • EP3038087B1 patent drawingFigure 4~5

AI summary

An electroluminescent display (10) and a method of driving the same are disclosed. In one aspect, the display includes a display panel (40) including a plurality of pixels (PX) configured to operate based on a first power supply voltage (ELVSS)having a negative voltage level. The display panel (40) is configured to generate at least one feedback voltage (VFB) corresponding to an ohmic drop (IRD) of the first power supply voltage (ELVSS). An analog-to-digital converter (50) is configured to generate at least one digital feedback signal (DG_VFB) based on the at least one feedback voltage (VFB). An adaptive voltage controller (20)is configured to generate a voltage control signal (DG_ELVSS) based on input image data (RGB_DATA), the at least one digital feedback signal (DG_VFB), a distribution of the input image data and the ohmic drop (IRD) of the first power supply voltage (ELVSS). A voltage converter (30)is configured to generate the first power supply voltage(ELVSS) based on an input voltage (VIN) and the voltage control signal (DG_ELVSS).