The Research Of Power And Driver For LED Backlight Of Large LCD TV

LED is having a significant impact in the backlight LCD TV field with the technology and performance improvement of LED (Light Emitting Diode) devices. LED backlight is well for energy consumption saving, wide color gamut, fast response, low driving voltage, long service life, mercury-free environmental protection and so on, which makes the use of LED as the backlight of LCD TV become a trend. LED backlight can be divided into direct mode, edge-lit mode, hybrid mode, etc. Among these types, because of its light weight, thin thickness and low cost, the edge-lit mode LED backlight makes the edge-lit mode LED backlight LCD TV become more and more popular among consumers, and gradually becomes the mainstream products of LED backlight LCD TV market. Because of the requirements of efficient energy saving and ultra-thin, higher requirements for the design of power and driver for edge-lit mode LED backlight of large LCD TV have been put forward at the same time.First of all, this paper introduces background, scientific research at home and abroad and the basic theories related to this subject. Then the design of power and driver for edge-lit mode LED backlight LCD TV is mainly researched and realized. Finally hardware implementation and performance tests based on the themes of "Energy-saving" and "Ultra-thin" are realized. The related innovations are as follows:With regard to the design of "Energy-saving":compared with the separate design, the design of integrating the LED power supply with LED driver into the same PCB greatly improves the efficiency of the system, improving the efficiency of the existing power supply system of edge-lit mode LED from 80% to 90%; ultra-low whole machine power consumption is realized when global dynamic LED backlight control is used to reduce the average power consumption of the 55-inch LCD TV from 120W to 90W; ultra-low standby power consumption is realized when Separate standby power supply is used to reduce the standby power consumption of LCD TV from 1W to 0.5W; ultra-high power factor is realized when active power factor adjusting circuit with constant on-time boundary is used to improve the power factor of system close to 1. Ultra-low switching losses and Ultra-high system efficiency are realized by LLC resonant converter. With regard to "Ultra-thin":the design of the LED driver uses the method of designing LED driver together with power on one side of PCB instead on both sides of PCB, which greatly reduced the cost of the overall space; It's greatly reduces the stringent and realizes 10mm ultra-thin design of power and driver PCB by the device selection and molding. These lay a foundation for the design of the overall ultra-thin design.The theoretical derivation and design implementation in this paper lay the foundation for further research and promotion of the "Energy-saving" design of power and driver for edge-lit mode LED backlight LCD TV.