OLED Power Supply Merging ELVDD and ELVSS Circuits
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Solution Overview
Problem
Conventional OLED displays have inefficiencies in their power supply systems, particularly the -ELVSS power source circuit, which results in increased costs and reduced power efficiency due to low converting efficiency and the need for separate +ELVDD and -ELVSS power source circuits.
Innovation Solution
A simplified power supply system for OLED displays that uses a single power supply unit with a bias circuit generating both ELVDD and ELVSS voltages, where the second power source voltage is referenced to ground, allowing current to flow to a reference terminal, thereby reducing costs and improving power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate -ELVSS power source circuit is used, then the OLED display can be illuminated, but the converting efficiency is low and the cost is increased
Solution Approach 1:
The patent combines the +ELVDD and -ELVSS power source circuits into a single integrated power supply unit. The power supply circuit generates a power supply voltage from an input voltage, and a bias circuit generates a bias voltage referenced to ground, eliminating the need for separate power source circuits and improving converting efficiency while maintaining illumination capability
2Reliability
If a separate +ELVDD and -ELVSS power source circuits are used, then the OLED display can be illuminated, but the cost is increased
Solution Approach 1:
The patent merges two separate power source circuits into one integrated power supply unit with a bias circuit, reducing the number of components and simplifying the manufacturing process, thereby reducing cost while maintaining the illumination capability of the OLED display
3Loss of energy
If a single power supply unit is used, then the cost is reduced and power efficiency is improved, but the structure must be simplified
Solution Approach 1:
The power supply unit is segmented into two functional modules: a power supply circuit that generates the power supply voltage from input voltage, and a bias circuit that generates the bias voltage referenced to ground. This segmentation allows for simplified structure and improved power efficiency while maintaining the necessary functionality
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 enhances power efficiency and reduces costs by simplifying the power supply structure, improving the overall performance of the OLED display while maintaining effective voltage generation for pixel illumination.
Implementation Method 1
a power supply circuit receiving an input voltage to generate a power supply voltage
Implementation Method 2
a bias circuit generating a bias voltage from the power supply voltage and referenced to a ground
Implementation Method 3
an organic light emitting diode (OLED) display displays an image by using light generated by an OLED by recombination of electrons and holes
Data Source
AI summary
An organic light emitting diode (OLED) display including: a display unit including pixels; and a power supply unit including: an output terminal; a reference terminal having an insulated output; and a bias circuit generating a first power source voltage from a received input voltage and supplying a second power source voltage to the reference terminal wherein the first power source voltage and the second power source voltage are voltages driving the plurality of pixels, wherein the bias circuit supplies the second power source voltage to the reference terminal and the plurality of pixels and is referenced to a ground voltage, and wherein a current flowing to the pixels flows to the reference terminal. In the OLED display, one power supply may be used as a power supply powering electroluminescence (EL), and thereby a cost of the OLED display may be reduced and a power efficiency may be improved.