In today’s world, where visualised information is ubiquitous, LED displays have become commonplace—from outdoor billboards to indoor smart terminals, from stage productions to immersive virtual production. Capitalising on inherent advantages like high brightness, a wide colour gamut, and seamless tiling, LED technology continues to push the envelope of its applications.
With the advancement of MLED technology, the industry’s demand for image precision and superior visual performance has reached unprecedented levels. However, the traditional PWM (Pulse Width Modulation) technology, which is critical for driving each LED emitting chip, has become a performance bottleneck, limiting the full potential of LED displays.
In this context, NovaStar’s Infinity Solution was developed. By combining a hybrid PWM+PAM driving architecture with intelligent algorithms and an advanced control platform, it delivers an unprecedented solution for ultra-high image quality to the LED display industry.
From PWM to PWM+PAM
Throughout the evolution of LED displays, PWM driving technology has long been the cornerstone, controlling brightness through modulation of the current’s on-time.
However, as MLED technology advances toward higher pixel densities, higher dynamic ranges, and more demanding application scenarios—such as virtual production, MLED TVs, and automotive transparent displays—the limitations of traditional PWM driving become apparent.
The primary limitation of conventional PWM driving lies in greyscale performance. In this scheme, the achievable greyscale depth is constrained by the greyscale clock (GCLK). At high greyscale depths such as 16-bit or 18-bit, the required GCLK frequency must exceed 30 MHz.
To achieve this, PWM chips typically resort to frequency-multiplication techniques, which exacerbate challenges in IC design and cost, and introduce detrimental side-effects such as electromagnetic compatibility (EMC) issues, poor low-greyscale uniformity, and high power consumption. As a result, a pure PWM driving method falls short of the demands for superior image quality.
In response to the stringent demand for supreme image quality within the constraints of large-scale commercialisation, the industry urgently requires a more intelligent and flexible driving method. As a solution, hybrid PWM + PAM driving technology has thus emerged, demonstrating its inherent advantages.
Infinity Solution: deep collaboration between drive IC, algorithms, and hardware
Optimising the image quality of an LED display is a systematic engineering endeavour. It cannot be achieved by any single technology in isolation, be it driving technology or control technology.
The Infinity Solution is built upon a foundation of hybrid PWM + PAM drive architecture. It achieves a breakthrough through the deep integration of the hybrid drive, intelligent algorithms, and an advanced control platform. These components are tightly interdependent, forming a cohesive system that orchestrates optimal image quality, thereby delivering an unprecedented enhancement.
The visual impact of an LED display primarily stems from its image contrast, which is determined by the ability to push the boundaries of both peak brightness and minimum black level. The Infinity Solution introduces a synergistic approach between PWM and PAM, creating a “dual-dimensional” control over brightness through both pulse width and current amplitude.
In high-brightness regions, building upon the PWM foundation, PAM further boosts the driving current, unleashing a more impactful peak luminance.
In low-greyscale regions, based on the minimum pulse width, PAM reduces the current amplitude, allowing the minimum brightness to reach a deeper, darker level.
This coordinated strategy not only expands the contrast ratio and dynamic range but also comprehensively enhances the precision of brightness control across the entire scale.
After expanding the dynamic range, the key to achieving superior image delicacy lies in dividing the luminance spectrum into a greater number of intermediate greyscale levels. This is achieved by NovaStar’s advanced MG algorithm, which dynamically selects the optimal combination of PWM and PAM for each greyscale level.
Leveraging a maximum 16-bit PWM depth and 8-bit PAM depth, the Infinity solution significantly expands the available greyscale levels. This capability reproduces more delicate gradients, ensuring clear details in both highlight and low-brightness areas, thereby delivering a smoother and more natural visual experience.
In the realm of colour accuracy, the Infinity solution demonstrates distinct advantages. LED spectra are prone to shift under varying driving currents, which leads to colour distortion. By leveraging the fine control precision of its hybrid drive architecture and the proprietary MG algorithm, the Infinity solution performs precise, step-by-step calibration of the RGB primary colours to accurately compensate for this shift.
This achieves a colour difference (ΔE) of ≤ 2—a level imperceptible to the human eye, representing exceptional color fidelity. Additionally, the colour temperature deviation is stabilised within ±100K(tested based on a 6500K standard).
In the dimension of refresh rate, the Infinity solution introduces PAM-based amplitude modulation, enabling pixel-level dynamic adjustment of the LED driving current. This approach creates a wider time window for screen refresh cycles, allowing for a significantly greater number of PWM actions. As a result, it achieves a high refresh rate in low-grey-scale areas while maintaining excellent low-grey performance. The refresh rate at 1 greyscale can be improved by 4 to 8 timescompared to traditional PWM technology.
Regarding display uniformity, the Infinity solution not only guarantees excellent uniformity across all greyscale levels through full greyscale calibration but also proactively compensates for LED thermal attenuation during extended operation. Its adaptive thermal compensation technology achieves this by leveraging a thermal distribution prediction model and real-time, per-pixel monitoring to dynamically adjust brightness and colour.
From technical superiority to application value
The true measure of any technology is the value it delivers in real-world applications. The uniqueness of the Infinity solution lies in its ability to address not just isolated issues, but to combine its multiple capabilities to meet the most demanding ultra-high image quality requirements across diverse scenarios.
In xR stages and virtual production, where the camera directly captures the LED volume, the demand for image quality is exceptionally high. While a high refresh rate is fundamental, it alone is insufficient. The display must also deliver high brightness to replicate lighting, high contrast to define depth, and high colour accuracy to ensure faithful colour reproduction.
The Infinity solution delivers a balanced combination of excellence across all these metrics. It ensures that the image is authentic to the naked eye on set and remains natural through the camera lens, thereby enabling a truly immersive experience for virtual production.
In mission-critical environments like command and control centres, the precise and reliable communication of information is paramount. This demands not only exquisite greyscale reproduction and ultra-high colour accuracy to ensure the legibility and accuracy of surveillance footage and on-screen data, but also stable long-term thermal compensation to prevent colour drift over extended periods. The comprehensive capabilities of the Infinity solution make it the ideal choice for such high-reliability applications.
In the high-end commercial display market, user experience boils down to three key attributes: a pleasing image, exceptional clarity, and flawless motion. This is achieved through cutting-edge performance: an ultra-high dynamic range for stunning contrast and detail, impeccable colour accuracy for true-to-life reproduction, a high bit-depth for exquisite detail and gradation, and a high refresh rate for perfectly smooth motion.
In application scenarios such as automotive displays and outdoor advertising, the Infinity solution offers distinct advantages in energy efficiency and operational stability. Its low power consumption contributes to an extended product lifespan and enhanced safety, while its low thermal output reduces the demand on cooling systems.
Furthermore, it ensures high brightness and exceptional colour fidelity even under direct sunlight. The Infinity solution thereby empowers these display applications to achieve a new level of reliability.
The Infinity solution represents a fundamental advancement in display driving technology. Architected on a hybrid PWM+PAM driving foundation, it achieves breakthrough performance through deep integration of intelligent algorithms with advanced display control systems. This systemic approach successfully addresses long-standing industry challenges, including greyscale limitations, refresh rate constraints, restricted dynamic range, colour temperature drift, and uniformity deficiencies that have persisted under conventional driving architectures for over a decade.
