Backlight Control Reduces Voltage Ripples in LED Arrays

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Solution Overview

Problem

The rapid change in current flowing through LEDs in backlight units leads to excessive voltage ripples, resulting in increased power consumption and temperature rise.

Innovation Solution

An electronic device with a processor that identifies the optimal number of time intervals for each backlight to be turned on, based on luminance information, and adjusts the timing of these intervals to minimize simultaneous backlight activation, thereby reducing voltage ripples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the number of light emitting elements in the backlight unit is increased to improve image quality and color expression, then the color accuracy and image quality are improved, but the power consumption and temperature rise increase

Engineering Contradiction:

Improvecolor accuracyVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The backlight unit is divided into multiple independently controllable light emitting elements (LEDs) arranged in a matrix pattern. Each LED can be controlled individually through separate current control circuits, allowing selective activation and dimming of specific regions to reduce overall power consumption while maintaining color accuracy in displayed areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements frame-by-frame control of the backlight where LEDs are activated only during their designated time intervals within each frame period. By dividing the display into multiple frames and controlling LEDs sequentially rather than continuously, the system reduces power consumption and heat generation while maintaining image quality through temporal multiplexing.

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If pulse width modulation with multiple subframes is used to control gray scale and reduce power consumption, then power consumption is reduced, but voltage ripples increase due to drastic current changes

Engineering Contradiction:

Improvepower consumptionVSAvoidvoltage ripples

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary cushioning by introducing voltage regulation circuits that prepare and stabilize voltage before it reaches the LEDs. By pre-regulating voltage and current in advance of the PWM switching events, the system reduces the magnitude of voltage ripples caused by abrupt current changes during subframe transitions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces constant current control circuits as intermediary components between the PWM control signals and the LED arrays. These control circuits act as buffers that smooth out current transitions, preventing direct transmission of voltage ripples to the LEDs while still enabling effective gray scale control through PWM modulation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the voltage supplied to LEDs is increased to compensate for voltage ripples, then the LED forward voltage requirement is met, but overall power consumption and temperature rise increase

Engineering Contradiction:

ImproveLED forward voltage stabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent dynamically adjusts the voltage supplied to LEDs based on real-time detection of voltage ripple conditions and LED forward voltage requirements. By changing voltage parameters adaptively rather than using a fixed high voltage, the system maintains reliable LED operation while minimizing power consumption and heat generation during normal operating conditions.

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

This approach reduces voltage ripples, lowers the voltage supplied to the backlights, decreases overall power consumption, and minimizes temperature rise.

Implementation Method 1

a backlight unit including a plurality of backlights... control the driving unit so that the plurality of backlights are turned on

Methodology Applied

Scientific EffectLight emitting diode effect: Light Emitting Diode

Implementation Method 2

based on luminance information of each of the plurality of backlights, identify a number of time intervals in which each of the plurality of backlights is to be turned on

Methodology Applied

Scientific EffectLuminance detection:

Data Source

PatentUS12322351B2Electronic device and control method therefor

Publication Date: 2025.06.03 SAMSUNG ELECTRONICS CO LTD

AI summary

An electronic device is disclosed. The electronic device includes a backlight unit including a plurality of backlights; a driving unit for driving the backlight unit; and a processor for identifying, based on luminance information about each of the plurality of backlights, a number of time intervals in which each of the plurality of backlights is to be turned on from among a plurality of time intervals included in a backlight dimming interval, and controlling the driving unit so that the plurality of backlights are turned on during the identified number of time intervals by variously changing times at which the plurality of backlights are turned on.