As a manufacturer specializing in display technology R&D, CNK Electronics understands that for digital screens requiring external key voltages such as AVDD, VCOM, VGH, and VGL, refined and forward-thinking circuit design is essential to avoid display defects and ensure long-term product reliability.
In the application design of customized LCD screens, power management is the core factor determining display quality and stability. As a professional LCD display manufacturer focused on display technology R&D, CNK Electronics (CNK) understands that for digital screens requiring external key voltages like AVDD, VCOM, VGH, and VGL, refined and forward-thinking circuit design is key to avoiding display defects and ensuring long-term product reliability.
Stable Power Supply is the Foundation of High-Quality DisplayFor digital LCD screens requiring external AVDD, VCOM, VGH, and VGL inputs, power stability directly determines the final visual experience. As a professional LCD display manufacturer, CNK Electronics points out that fluctuations in AVDD, VGH, and VGL directly affect the voltage value of the common terminal VCOM. Therefore, ensuring the fluctuation of these three key voltages does not exceed 0.1V is crucial, especially in applications with stringent requirements against image retention and flicker. This is the foundation for achieving stable and pure image quality in all LCD modules.
Key Circuit Design Enhances Display ConsistencyFor specific circuit design in your customized LCD screen projects, we provide two core recommendations. Firstly, it is recommended to derive the VCOM voltage from the AVDD supply via a voltage divider. This approach effectively counteracts the impact of AVDD’s own fluctuations on VCOM, creating a natural compensation mechanism. Secondly, connecting a 4.7μF/10V capacitor between VCOM and GND can significantly enhance the TFT’s driving capability and is a simple and effective method to eliminate vertical streaks. These detailed considerations reflect an LCD display manufacturer’s deep control over display quality.
Flexible Design Coping with Differences and VariationsConsidering the differences in manufacturing processes of different LCD modules, motherboard output characteristics, and usage environments, the VCOM voltage might have a deviation of around ±1.0V. Therefore, for customers with strict display effect requirements, it is essential to include a variable resistor for VCOM on the motherboard, allowing adjustment within approximately ±1.0V of the standard value. Simultaneously, for applications with high heat generation or significant ambient temperature changes, strongly recommended is adding a VCOM temperature compensation circuit (VCOM decreases by about 0.2V when temperature rises from 19°C to 40°C). This flexible design ensures the excellent performance of customized LCD screens under various complex working conditions.
Attention to Detail Ensures Long-Term Operational ReliabilityA detail often overlooked but critical for long-term reliability is the inclusion of 30-50 KΩ discharge resistors on the AVDD, VGH, and VGL lines. This design prevents flickering or display abnormalities during frequent sleep and wake cycles; however, the resistance value should not be too small either, to avoid insufficient driving capability. As a reliable LCD display manufacturer, every design recommendation provided by CNK Electronics aims to ensure the long-term stability of your products.
In conclusion, a successful LCD screen design hinges on careful consideration of power parameters like AVDD, VCOM, VGH, and VGL. Every step is crucial—from ensuring voltage stability and optimizing basic circuits to providing adjustment headroom and compensating for environmental changes. Choosing CNK Electronics as your LCD display manufacturer means you will receive not only high-performance customized LCD screens or modules but also our profound expertise and technical support.
CNK Electronics (CNK in brief) was founded in Shenzhen in 2010 and expanded its investment in Wuping, Fujian in 2019. It is a specialized and innovative enterprise engaged in the design, development, production, and sales of display products. The company is committed to the perfect integration of smart technology and display technology, providing customers worldwide with high-quality, cost-effective small and medium-sized display screens, solutions, and services. With technology as the guide and quality as the foundation, CNK adheres to the concept of sustainable development and strives to become a new leader in the display industry, offering customers better, more stable, and faster services.