Display Backlight Power Circuit With Shared LED String Voltage Control

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Solution Overview

Problem

The existing power supply circuits for display apparatuses, particularly in devices like TVs, are complex and costly due to the need for multiple LLC modules and voltage adjustment modules for each LED string, leading to increased transformer design complexity and thermal loss.

Innovation Solution

A simplified power supply circuit design that shares a secondary coil and voltage conversion module for two LED strings, using a transformer with alternating output voltages and feedback mechanisms to adjust the superimposed voltage, reducing thermal loss and circuit complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple secondary windings and voltage adjustment modules are used to manage power requirements of LED strings, then voltage adjustment capability is improved, but device complexity increases

Engineering Contradiction:

Improvevoltage adjustment capabilityVSAvoidpower supply circuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple secondary windings into a single secondary winding and combines multiple voltage adjustment modules into one shared module. This single secondary winding provides power to multiple LED strings, and the shared voltage adjustment module regulates voltage for all strings, thereby reducing circuit complexity while maintaining voltage adjustment capability through centralized control.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single secondary winding and shared voltage adjustment module are designed to serve multiple LED strings simultaneously. The voltage adjustment module can dynamically adjust voltage levels to accommodate different power requirements of multiple LED strings, making the power supply system universal and adaptable to various configurations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple voltage adjustment modules are used for each LED string, then voltage control precision is improved, but thermal loss increases

Engineering Contradiction:

Improvevoltage control precisionVSAvoidthermal loss

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

By consolidating multiple voltage adjustment modules into a single shared module, the patent reduces the total number of active components that generate heat. The shared module can efficiently manage voltage distribution across multiple LED strings with fewer power conversion stages, thereby reducing cumulative thermal losses while maintaining precise voltage control through centralized regulation.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If multiple secondary windings are used for different LED strings, then power distribution flexibility is improved, but transformer design difficulty increases

Engineering Contradiction:

Improvepower distribution flexibilityVSAvoidtransformer design difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple secondary windings into a single secondary winding, significantly simplifying transformer design and manufacturing. The single winding approach eliminates the complexity of designing and assembling multiple windings with different turns ratios, making the transformer easier to manufacture while the voltage adjustment module provides the necessary power distribution flexibility to multiple LED strings.

Inventive Principle:

Principle #5Merging (Combining)

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 simplifies the power supply circuit, reduces thermal loss, and lowers costs by sharing components across LED strings, while maintaining stable current and voltage levels.

Implementation Method 1

a transformer, a voltage conversion module, a feedback module, and a light string group. The voltage conversion module corresponds one-to-one with the light string group... The first secondary coil and a second secondary coil of the transformer are coupled with a primary coil of the transformer. The first secondary coil is configured to output a first voltage according to a power received by the primary coil. The second secondary coil is configured to output a second voltage from both ends of the second secondary coil alternately according to the power received by the primary coil.

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS12593379B2Display apparatus

Publication Date: 2026.03.31 HISENSE VISUAL TECH CO LTD

AI summary

Disclosed is a display apparatus. The display apparatus includes: a transformer, voltage conversion modules, a feedback module and a light string group. The light string group includes a first light string and a second light string; a first secondary coil and a second secondary coil of the transformer are coupled with a primary coil of the transformer; the first secondary coil is configured to output a first voltage according to a power received by the primary coil. The second secondary coil is configured to output a second voltage from both ends of the second secondary coil alternately according to the power received by the primary coil. The voltage conversion module is configured to generate an additional voltage according to the first voltage, and superimpose the additional voltage onto a corresponding second voltage at both ends of the second secondary coil to output a superimposed third voltage.