A Design Of 300W LCD TV Power Supply

With the rapid development of power electronics industry and innovation, a variety of electronic products gradually appear in every corner of our lives, accompanied by people saving, environmental protection and increasing awareness, setting off a new round of global energy revolution. Erp pioneered the implementation of the EU standards, followed by the United States to implement the Energy Star standards, the global supply of the equipment have become increasingly demanding. It requires not only the output of the switching power supply is stable and reliable, low voltage output ripple but also requires high power factor, high efficiency and strong anti-interference ability, especially standby power consumption is small. For now, the main content of research is power factor correction, soft-switching technology, electromagnetic compatibility, etc.Based on the actual demand, the design of a 90 V ~ 264 V AC nominal input, with 300 W output power, the three-channel DC output(24V power supply for the backlight, 12 V for the amplifier power supply, 5V for auxiliary and standby power) LCD TV power. According to industry standard of high-power LCD TV power, and in order to meet the actual technical requirements, the circuit structure is divided into two parts, the first part is the power factor correction circuit which uses two-phase interleaved BOOST structure. With this circuit not only improve the input power factor, but also effectively reduce the PFC inductor height to suit the needs of ultra-thin LCD TV. The latter part is a half-bridge LLC resonant circuit that can reduce power consumption by soft-switching technology, and improve the conversion efficiency of the ultimate power.This paper introduced the development direction of the LCD TV power supply, and then analyzed the basic principles of switching power supply, classification and development prospects. In this discussion of the basic principles and significance of power factor correction, based on the use of UCC28060 PFC circuit chip design, including design and component selection parameter calculation. Next, it introduced the basic principle of the half-bridge LLC resonant converter, DC steady state characteristics in detail and the impact of crucial parameters on the performance of the converter. It described the design method of using L6599 half bridge LLC resonant circuit chip, which included the calculation of parameters, component selection, auxiliary power supply design and EMI circuit design.According to principle diagram of the circuit drew the PCB and made the experimental prototype. Finally, the prototype of the modulation analysis and performance testing of failure were treated.