Micro-LED Pixel Driving Circuit for Adaptive PWM Grayscale Control
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Solution Overview
Problem
Micro-LED displays face challenges with high power consumption, overheating, and insufficient precision at low grayscale levels, particularly in 10-bit displays, which affect image quality and efficiency.
Innovation Solution
A pixel driving circuit incorporating a first multiplexer, frequency divider circuit, first and second bit counters, and a switch controller to dynamically adjust the frequency and bit depth of PWM signals based on grayscale data, optimizing power usage and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If 10-bit PWM signal is used for micro-LED display, then device complexity is reduced, but measurement precision deteriorates at low grayscale levels
Solution Approach 1:
The patent implements dynamic bit depth adjustment where the PWM signal transitions from 10-bit to 12-bit resolution based on grayscale level thresholds. When grayscale values fall below a predetermined threshold (indicating low brightness regions), the system switches to 12-bit PWM signaling to provide finer precision. This dynamic adaptation resolves the contradiction by using higher complexity only when necessary for precision.
Solution Approach 2:
The patent changes the parameter of PWM signal bit depth from fixed 10-bit to variable (10-bit or 12-bit) based on grayscale level conditions. This parameter change allows the system to optimize between complexity and precision by selecting the appropriate bit depth according to the specific grayscale requirements of different display regions.
2Illumination intensity
If micro-LED brightness is increased, then illumination intensity is improved, but power consumption increases
Solution Approach 1:
The patent changes the PWM signal frequency parameter dynamically based on grayscale levels. For high grayscale values (bright regions), a lower PWM frequency is used, while for low grayscale values (dark regions), a higher PWM frequency is applied. This parameter adjustment optimizes power consumption by matching the driving frequency to the actual brightness requirements, reducing energy waste in bright areas while maintaining precision in dark areas.
3Illumination intensity
If micro-LED brightness is increased, then illumination intensity is improved, but temperature increases
Solution Approach 1:
The patent employs PWM (pulse width modulation) which inherently uses periodic action to control LED brightness. By modulating the duty cycle and frequency of periodic PWM signals rather than continuously driving the LED at high current, the system achieves high illumination intensity when needed while allowing thermal dissipation during the off-periods of the PWM cycle, thus mitigating overheating issues.
4Measurement precision
If PWM frequency is adjusted for grayscale precision, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the grayscale control into different frequency bands. A first PWM frequency is used for high grayscale levels (bright regions) where lower precision is acceptable, while a second, higher PWM frequency is used for low grayscale levels (dark regions) where higher precision is critical. This segmentation allows precision optimization without requiring the entire system to operate at maximum complexity.
Solution Approach 2:
The patent introduces a frequency selection mechanism that acts as an intermediary between the grayscale data signal and the PWM generation. This intermediary selectively routes or adjusts the PWM frequency based on the grayscale level, enabling dynamic precision adjustment without requiring complex circuitry to be active at all times. The intermediary simplifies the overall system by activating complexity only when needed.
Data Source
AI summary
A micro-LED display panel and its pixel driving circuit are provided. A first multiplexer switches a base frequency clock signal to a frequency divider circuit or a first bit counter according to a grayscale data signal. The frequency divider circuit divides the base frequency clock signal transmitted by the first multiplexer into a divided base frequency clock signal. The first bit counter counts the base frequency clock signal transmitted by the first multiplexer to generate a first switching signal. A second bit counter counts the divided base frequency clock signal transmitted by the frequency divider circuit to generate a second switching signal. A switch controller switches a switch of at least one pixel circuit according to the first switching signal or the second switching signal.