Distributed Charge-Pump Power-Supply System for Micro-LED Displays
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Solution Overview
Problem
Inorganic light-emitting diodes (μLEDs) with different materials and manufacturing processes exhibit variability in performance and efficiency, leading to inefficiencies when connected to a common power supply, particularly in micro-LED displays where material variability is exacerbated on a smaller scale.
Innovation Solution
A spatially distributed charge-pump power-supply system with separate charge-pump circuits providing tailored power supplies to each μLED, allowing for distinct voltage connections for each color of light-emitting diode, thereby addressing the variability in μLED performance and requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common power supply is used for all inorganic LEDs, then the device complexity is reduced, but the electrical efficiency and performance uniformity deteriorate due to material variability
Solution Approach 1:
The patent divides the common power supply into multiple separate charge-pump circuits, with each circuit dedicated to a specific inorganic LED or group of LEDs. This segmentation allows each charge pump to be optimized for its specific LED's electrical requirements, thereby improving electrical efficiency while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The patent implements local quality by providing tailored power supply characteristics to different regions or groups of LEDs based on their specific material properties and electrical requirements. Each charge-pump circuit is configured with local optimization parameters (such as pumping voltage, capacitance values, and switching frequencies) that match the specific LED it serves, thereby maximizing electrical efficiency for each local region.
2Loss of energy
If separate charge-pump circuits are provided for each inorganic LED, then the electrical efficiency is improved, but the device complexity and number of interconnections increase
Solution Approach 1:
The patent merges multiple charge-pump circuits into an integrated circuit structure that can be fabricated as a single monolithic device. This merging approach reduces the physical footprint and interconnection requirements while maintaining the electrical separation and optimization benefits of individual charge-pump circuits for each LED, thereby improving electrical efficiency without proportionally increasing device complexity.
3Loss of energy
If more interconnections are added to distribute power to each LED, then the power delivery is optimized, but the manufacturing yield decreases
Solution Approach 1:
The patent designs the charge-pump circuits with universal functionality that can serve multiple purposes: they provide optimized power delivery to specific LEDs, perform local electrical characterization, and enable efficient current recycling. This multi-functionality reduces the need for separate dedicated interconnections for each function, thereby improving power delivery optimization while maintaining high manufacturing yield through reduced interconnection density.
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 distributed charge-pump power-supply system enhances electrical efficiency, aperture ratio, and yield by providing optimized power to each μLED, reducing losses and improving display performance.
Implementation Method 1
An example prior-art charge-pump circuit includes two input voltage lines (e.g. power and ground) connected across an input capacitor CIN. A switch (S1) is connected in each of the input voltage lines and another capacitor, conventionally called the flying capacitor CFLY, is connected across the input lines after the switches S1.
Implementation Method 2
In operation over time the charge-pump circuit tends to provide the same voltage across the input lines and the output lines, as charge is pumped from the first capacitor to the flying capacitor to the output capacitor.
Data Source
AI summary
A distributed charge-pump power-supply system includes a system substrate with a plurality of separate electronic elements spatially distributed over the system substrate. Each electronic element includes first and second sub-elements requiring first and second different operating voltage connections. A plurality of separate charge-pump circuits are also spatially distributed over the system substrate. Each charge-pump circuit has a common charge-pump power supply connection and provides the first and second voltage connection supplying operating electrical power to the first and second sub-elements. The electronic elements are arranged in groups of one or more electronic elements and the first and second voltage connections for each group are provided by a charge-pump circuit.