Display PWM Pulse Sequencing for Peak Current Reduction

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Solution Overview

Problem

Displays using micro-LEDs face significant power supply challenges due to high current draw when using identical or similar PWM pulse patterns across multiple pixels, leading to overheating and voltage drops, which conventional power supplies struggle to manage.

Innovation Solution

Implementing diverse PWM pulse patterns, such as shifted, randomized, or accelerated illumination, to distribute the current draw more evenly over time, utilizing coupling capacitors and dynamic algorithms to optimize pixel illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If identical or similar PWM pulse patterns are used across multiple pixels, then the display achieves consistent illumination control, but the power supply experiences high current draw and voltage drops

Engineering Contradiction:

Improveillumination control consistencyVSAvoidcurrent draw

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent divides the pixel array into multiple groups or zones, each with independently controllable PWM patterns. This segmentation allows different groups to use different pulse timing sequences, spreading out the current demand across time rather than having all pixels draw current simultaneously, thus reducing peak current draw while maintaining illumination control consistency within each group

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic PWM pattern adjustment where the pulse timing and sequencing are varied over time across different pixel groups. This dynamic approach allows the system to maintain consistent visual output while dynamically redistributing power consumption, preventing sustained high current draw on any single power supply line

Inventive Principle:

Principle #15Dynamics

2Illumination intensity

If high current is drawn to illuminate multiple pixels simultaneously, then the display achieves bright and uniform illumination, but the power supply voltage drops and overheating occurs

Engineering Contradiction:

Improvepixel brightnessVSAvoidpower supply temperature

Core Design Contradiction:

Illumination intensityVSTemperature

Solution Approach 1:

The patent employs periodic PWM signaling with carefully designed duty cycles and timing sequences. By using periodic rather than continuous high-current illumination, the system achieves the required brightness through rapid on-off cycling while allowing the power supply to recover between cycles, reducing average power consumption and heat generation while maintaining perceived illumination intensity

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent changes the temporal parameters of the illumination signal by varying PWM duty cycles, pulse widths, and timing sequences across different pixel groups. This allows the system to achieve uniform brightness perception through parameter variation rather than uniform high-current application, reducing overall power supply stress and temperature rise

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If PWM pulses are temporally aligned across pixels, then the control logic is simplified, but the power supply must handle peak current demands

Engineering Contradiction:

Improvecontrol logic complexityVSAvoidpeak current demand

Core Design Contradiction:

Device complexityVSPower

Solution Approach 1:

The patent segments the pixel array into multiple controllable groups with independently adjustable PWM timing. This segmentation adds minimal control complexity while effectively distributing peak current demands across different time periods for different groups, as each group can be illuminated in staggered sequences rather than all simultaneously

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic timing adjustment where PWM pulse sequences are varied over time across different pixel groups. This dynamic approach maintains relatively simple control logic through systematic timing patterns while preventing simultaneous peak current demands by continuously shifting which groups are actively illuminated

Inventive Principle:

Principle #15Dynamics

4Productivity

If rapid PWM switching is used to control pixel brightness, then the display achieves high refresh rates and responsiveness, but eye motion artifacts become more visible

Engineering Contradiction:

Improverefresh rateVSAvoiddisplay artifacts

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different PWM timing characteristics to different spatial regions or groups of pixels. By varying the temporal illumination patterns locally across different pixel groups rather than using a uniform approach, the system maintains high refresh rates while reducing the visibility of eye motion artifacts through localized timing optimization that accounts for perceived motion effects

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250378782A1Pulse width modulation (PWM) for displays

Publication Date: 2025.12.11 TECTUS CORP

AI summary

Pulse width modulation is used to drive pixels in a video display. Bit codes are received for pulses that drive at least two different pixels of a video display. The bit codes specify which pulses are on or off within illumination windows for the pixels. The illumination windows for the different pixels are temporally aligned. Pulses are generated from the bit codes. The order of the pulses within the illumination windows is different for the different pixels.