Flat-panel Tv Power

Recently, panel TV industry grows rapidly. The competition becomes crueler and crueler between industries day after day. It is not only an opportunity but also a challenge to panel TV power supply. The opportunity is that panel TV industry impels the development for the power supply industry. While the challenge is that high requirement for panel TV power supply is proposed, such as high efficiency, high power density, low cost, low standby loss. The purpose of this article is attempt to search a proper topology which gives a considerable design scheme producing panel TV power with low cost, low standby loss and high efficiency.Special requirement for panel TV power supply is analyzed and proper scheme is selected for some parts of panel TV power supply. Detailed design process of Low cost, low standby loss, high efficiency topology is proposed. PFC circuit control method of middle or low power level is analyzed. Design of critical mode PFC circuit is provided as well. LLC topology, which is widely studied nowadays, is selected as DC-DC circuit and is used in the design scheme for panel TV power supply successfully. This theory points out the difficulty in design process. Then detailed design process is described, including the transformer design, input impedance characteristic, resonant parameters selection, small signal modeling, over current protection and so on. EMC consideration and real design method is presented according to the prototype. Also method for standby circuit and design parameters are given.The prototype fully attains the requirement for high efficiency, low cost, low standby loss. The efficiency is high up to 88.5% at 220V input voltage. Standby loss is less than 0.75W.