Design Recommendations for Digital Screens with AVDD, VCOM, VGH, VGL Inputs – CNK Electronics Assists You in Creating Stable LCD Modules

  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 Display
For 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 Consistency
For 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 Variations
Considering 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 Reliability
A 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.

About CNK

  Founded in Shenzhen in 2010, CNK Electronics (CNK in brief) expanded the world leading factory in Longyan, Fujian in 2019. It is a specialized and innovative enterprise specializing in the design, development, production and sales of display products. CNK provides customers with a full range of cost-effective small and medium-sized display modules, solutions, and services with excellent quality worldwide. Oriented in technology and high quality, CNK keeps sustainable development, works to offer customers  better and stable services.