Design and implementation of a digitalized power supply for large scale LCD TV

The main purpose of this paper is to research and implement a digitalized power supply for large scale liquid crystal display (LCD) TV. The whole system configuration can be divided into three major parts. An interleaved continuous conduction mode (CCM) power factor corrector (PFC) in front stage is employed as pre-regulator for improving the input power factor and reducing the total harmonic distortion. A half-bridge LLC resonant converter with zero voltage switching (ZVS) capability is utilized as the DC/DC conversion stage. Finally, the dsPIC30F2020 from Microchip corp. is used as the digital variable frequency controller of LLC series resonant converter. The advantages of the digital controller include components cost reduction and more flexible design. Digital power stage also provides intelligent adaptability and flexibility to satisfy any complex power requirement with the straightforward ability to monitor, process and adapt to system conditions. Experimental results will be given to validate the correctness of the proposed system and the measured efficiency of the whole system achieved 82%.