TFT LCD modules are thin film field effect transistors. The so-called thin film transistor means that each liquid crystal pixel on the liquid crystal display is driven by a thin film transistor integrated behind it so that it can display screen information with high speed, high brightness, and high contrast. The composition of the liquid crystal display is not complicated. The liquid crystal panel plus the corresponding driving board (also called the main board, whose compositional structure is not intended to be the row and column driving circuit in the liquid crystal panel), power supply board, high voltage board, button control board, etc., constitute a complete liquid crystal display.
Power supply part: The power supply circuit of the liquid crystal display is divided into two parts: switching power supply and DC/DC converter. Among them, the switching power supply is an AC/DC converter, its function is to convert the AC 220V or 110V (European standard) into a 12V DC power supply (some models are 14V, 18V, 24V, or 28V), supply DC/DC Converter and high-voltage board circuit; DC/DC DC converter is used to convert the DC voltage (such as 12V) generated by the switching power supply into 5V, 3.3V, 2.5V and other voltages, which are supplied to the driver board and the liquid crystal panel.
The driver board of the TFT LCD screen is also called the main board, which is the core circuit of the liquid crystal display. It is mainly composed of the following parts: input interface circuit, A/D conversion circuit, clock generator, Sealer circuit, microcontroller circuit, and output interface circuit.
Key board part: The key circuit is installed on the key control board, and the indicator lights are generally also installed on the key control board. The function of the key circuit is to make the circuit on and off. When the switch is pressed, the key electronic switch is turned on, and when the hand is released, the key electronic switch is turned off. The switch signal output by the key switch is sent to the MCU on the driver board. After being recognized by the MCU, the control signal is output to control the relevant circuit to complete the corresponding operation and action.
High-voltage board part: The high-voltage board is commonly known as a high-voltage strip (because the circuit board is generally long and in the form of a strip), and is sometimes called an inverter circuit or an inverter. Its function is to convert the low-voltage DC voltage output by the power supply into a liquid crystal panel ( The high-frequency high-voltage AC above 600V required by the Panel) that lights the backlight on the LCD panel. The high-voltage board of the TFT LCD screen mainly has two installation forms: 1. A dedicated circuit board; 2. It is installed together with the switching power supply circuit (the switching power supply adopts the internal type).
LCD panel part: The LCD panel is the core component of LCD, mainly including the LCD screen, LVDS receiver (optional, LVDS LCD screen has this circuit), driver IC circuit (including source driver IC and gate driver IC), timing sequence Control IC (TC0N) and backlight.