.dc / Dc Digitally Controlled Power To Reduce Output Ripple

The requirement of high performance and precision power supply is greatly increased with the development of switching power supply technology. The output ripple is a very important parameter of switching power supply. In this dissertation, some research works have been done to reduce the amplitude of output voltage ripple to be accepted degree.At the begin of the dissertation, some technical requirements of a digital controlled precision power DC/DC supply are introduced Based on these requirements, the method of ripple suppression is analyzed in detail, and the outline of this system and some optional schemes of main circuits are also given.Then some new schemes are proposed in different aspects of the power supply in order to decrease the amplitude of output voltage ripple. The novel schemes of three stages in series and double-stage linkage are introduced. The scheme of three stages in series can alleviate the low frequency ripple effectively and the double-stage linkage scheme has lower output ripple when lower voltage output is needed. Some advanced switching power supply technologies are also used in three different stage: a scheme to alleviate the rectifier reverse-recovery problem is usedin the power factor correction circuit stage, zero-voltage phased-shifted full bridge circuit with a current doubler rectifier is applied in the DC/DC isolated stage, and a two stage filters and the technology of alleviation the reverse-recovery problem are adopted to the precise output stage.In this dissertation, the plan of two power blocks' parallel connection with the interleaved control method to reduce the ripple is suggested and some important parameters in the power supply system is also analyzed and optimized.Finally, a experimental power supply is made based on these schemes. The amplitude of the output voltage ripple satisfies the technical requirement .The analysis and proposal schemes are verified by circuit experiment.