RGB classification of LCD display EMI problems and solutions of RGB screen part one

1. Introduction

With the advancement and development of electronic technology, our lives are filled with all kinds of electronic products. LCD module are one of them. They are widely used in mobile phones, computers, instruments and other products. The current mainstream LCD display interfaces are RGB and LVDS. , MIPI and HDMI. Today I will briefly talk to you about the RGB signals of LCD display.

2 RGB classification

RGB generally refers to the RGB color model, which is a color standard in the industry. Various colors are obtained through the changes and superposition of the three primary color channels of red, green, and blue. In our lives, basically all colors are closely related to these three primary colors.

In addition to the most common RGB24, also known as RGB888, there are also RGB565, RGB555, RGB888, RGB16, RGB24, and ARGB32; there are two main RGB16 data formats: RGB565 and RGB555.

RGB565: R-5bit, G-6bit, B-5bit, 16 bits, 2 bytes

RGB555: R-5bit, G-5bit, B-5bit, 16 bits, 2 bytes (the highest bit is not used)

RGB24 data format: RGB888.

RGB888: R-8bit, G-8bit, B-8bit, 24 bits, 3 bytes (the order of RGB components is: BGR BGR BGR...)

ARGB32 data format: ARGB8888.

ARGB8888: R-8bit, G-8bit, B-8bit, alpha-8bit, 24 bits, 3 bytes

(The order of RGB components is: BGRA BGRA BGRA...; alpha: transparency channel)

EMI issues with three RGB screens

Because the RGB interface signal voltage is high, there are many connections, and the transmission cable is long, the circuit's anti-interference ability is relatively poor and it is prone to electromagnetic interference (EMI). Driving an RGB display screen generally includes four major types of signals: RGB data signal, clock signal, control signal and backlight power supply.

Most of the headaches for engineers are the following problems: (1) RGB clock radiation problem is serious; (2) RGB data envelope exceeds the standard; (3) RGB data has clock radiation problem; (4) Screen cable is too long , forming a radiating antenna