Nowadays, intelligent products are very popular among people. Many manufacturers will enter this industry. Here, the editor will talk about TV LCD screens for you. Its structure mainly includes: LCD display module, power module, driver module, and key module. Usually, LCD module manufacturers have completed electromagnetic compatibility (EMC) testing before production. EMC is an inevitable and important issue in the design of LCD TV screens. If the EMC design is not good, it will lead to weak anti-interference ability, water ripple and flicker issues during the television broadcasting process, and in severe cases, it will be impossible to watch. The following is a brief description of EMC's key component design:
The most important means to overcome electromagnetic interference is grounding. The LCD module screen TV main driver board mainly includes: analog signal part, high-speed digital circuit part, and noise source DC-DC power supply part. The grounding of the LCD TV power supply (DC-DC) is mainly separated from the grounding of other parts such as decoding and main chip processing to reduce the interference of power grounding on image display and TV sound. DC-DC power supply and grounding: On printed circuit boards, the power cord and grounding wire are the most important. Provide separate power and ground paths for analog and digital circuits.
Use of protective covers: Generally, LCD display modules, main control boards, and power supply parts require protective covers. The main frequency of the main chip is the main cause of electromagnetic interference. The frequency harmonics of the main frequency are most likely to generate electromagnetic interference. In electromagnetic compatibility experiments, there is significant electromagnetic interference in the frequency of the main frequency and the position of the harmonic wave. In the design, some shielding measures should be added to the main chip. The main shielding measure is to add a metal shield on the digital board. Adding a shielding cover is the most effective way to resist electromagnetic interference.
The LCD TV power supply adopts a switch power supply. The reasons for electromagnetic interference generated by switching power supplies are very complex. The two main functions of the power section are to drive the backlight of the LCD screen and provide DC power to other modules (including the driver module and button module). The design of the power module directly affects the entire system. If the design is not good, it can cause the TV to generate large water waves, and in severe cases, it can cause the TV to malfunction. At the same time, it will seriously affect the normal use of other nearby equipment.