Two-Stage LED Display Power Supply With Flyback-LLC and Buck

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Solution Overview

Problem

Existing LED display systems with common-anode architecture require two flyback/LLC converters or a dual-output converter to provide voltages for red, green, and blue LEDs, leading to increased cost, size, and efficiency losses due to large transformer losses and poor cross-regulation.

Innovation Solution

A two-stage power architecture using a single-output flyback/LLC converter coupled with a buck regulator, where the flyback converter provides voltage to green and blue LEDs and the buck regulator provides a floating ground voltage for the red LED, reducing system size, cost, and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two flyback/LLC converters are used to provide voltages for red, green, and blue LEDs, then voltage delivery to different LED types is improved, but device complexity and cost increase

Engineering Contradiction:

Improvevoltage deliveryVSAvoidnumber of converters

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the power conversion function into two distinct stages: a flyback/LLC converter for high-voltage generation and a buck converter for precise voltage regulation. This segmentation allows each converter to be optimized for its specific function, improving overall voltage delivery while reducing the complexity compared to using two full-bridge flyback/LLC converters.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines the high-voltage generation function (flyback/LLC) with the voltage regulation function (buck converter) into a single integrated power supply system. This merging eliminates the need for multiple independent flyback/LLC converters while maintaining reliable voltage delivery to different LED types.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If two flyback/LLC converters are used to provide voltages for red, green, and blue LEDs, then voltage delivery to different LED types is improved, but system size increases

Engineering Contradiction:

Improvevoltage deliveryVSAvoidsystem size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

By segmenting the power conversion into two specialized stages, the patent reduces the overall system size. The buck converter is significantly smaller than a flyback/LLC converter, and using one buck converter instead of one additional flyback/LLC converter reduces the total volume while maintaining voltage delivery reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The integration of high-voltage generation and voltage regulation into a single system reduces the total space required. The combined system eliminates redundant components and allows for compact arrangement, reducing system size compared to using two separate flyback/LLC converters.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If two flyback/LLC converters are used to provide voltages for red, green, and blue LEDs, then voltage delivery to different LED types is improved, but energy efficiency deteriorates due to transformer losses

Engineering Contradiction:

Improvevoltage deliveryVSAvoidtransformer losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent segments the power conversion function to use a buck converter for the final voltage regulation stage. Buck converters have significantly lower transformer losses compared to flyback/LLC converters, thereby improving energy efficiency while maintaining reliable voltage delivery through the two-stage architecture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the operating parameters and topology of the power conversion system by introducing a buck converter stage. This parameter change optimizes the system for lower losses during the voltage regulation phase, improving overall energy efficiency while maintaining the voltage delivery performance needed for different LED types.

Inventive Principle:

Principle #35Parameter changes

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 two-stage power architecture achieves higher efficiency (88% compared to 84%) and reduces system size and thickness by eliminating the need for multiple transformers, while maintaining proper voltage delivery to each LED type.

Implementation Method 1

Flyback/LLC converters include a resonant tank circuit that has two inductors and a capacitor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Flyback/LLC converters include a resonant tank circuit that has two inductors and a capacitor

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 3

a buck regulator coupled to the single-output flyback/LLC converter

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250008623A1Two-stage power supply architecture with flyback/LLC and buck converter for LED display

Publication Date: 2025.01.02 TEXAS INSTRUMENTS INC

AI summary

In an example, a system includes a single-output flyback/LLC converter adapted to be coupled to an alternating current (AC) power supply. The system also includes a buck regulator coupled to the single-output flyback/LLC converter. The system includes a first LED including an anode coupled to the single-output flyback/LLC converter and a cathode coupled to the buck regulator. The system also includes a second LED including an anode coupled to the single-output flyback/LLC converter and a cathode coupled to a ground terminal.