What is the circuit design concept for LCD liquid crystal screens?

　　Today, the editor will introduce to you the circuit design ideas of LCD liquid crystal screens.

　　When an LCD screen is in operation, there are mainly two places where points are present: the drive circuit on the PCB substrate and the leads of the backlight. The electrical design related to the PCB substrate is EMI design, and the electrical design of the backlight lead is insulation withstand voltage design. This article introduces the circuit design ideas of LCD liquid crystal screens from two aspects: EMI design and insulation withstand voltage design.

　　EMI of PCB substrate

　　EMI is the fundamental cause of electrical interference. When designing a signal processing board, sufficient electrical design countermeasures must be adopted. The main method is to cover the substrate with a metal shielding cover or use shielding strips to block the influence of external electromagnetic interference on the substrate. To prevent the loosening of the metal shielding layer and the formation of contact resistance, multiple connections can be made using screws or contact pieces. In addition, connecting the signal ground on the signal substrate to the ground on the metal plate can also reduce the leakage of electrical interference to the outside. Meanwhile, conductive tape can also be used to enhance the contact between sheet metal parts and the substrate.

　　2. Insulation withstand voltage of LED backlight

　　LED backlighting does not require high-voltage driving, while CCFL needs several thousand volts of high-voltage driving. Therefore, the dielectric withstand voltage design of the liquid crystal module is targeted at the structure of CCFL backlighting. The design requirements for insulation withstand voltage stipulate that the structural design must meet the standards for electrical insulation withstand voltage capacity, as well as the requirements for the spatial distance and separation distance of the insulating medium. It is necessary to clearly define the maximum voltage value specification of the lamp's wire, pay attention to the maximum movement range between the high-voltage area and the insulating components, as well as the distance between the high-voltage area and the insulating components. Conductive components, as well as between transformer coils, high-voltage terminals and conductive components. Distance.

　　The above has introduced the key points of circuit design ideas from two aspects: EMI design and insulation withstand voltage design. Has everyone learned it?