A novel closed loop interleaving strategy of multiphase critical mode boost PFC converters

In high power application, power factor correction (PFC) pre-regulators are generally required. PFC pre-regulators could achieve unity power factor, reduce line input current harmonics and utilize full line power. Interleaving PFC converters could reduce input ripple current, output capacitor ripple current and inductor size. This paper presents a new closed loop interleaving strategy of multiphase critical mode boost PFC converters. Hardware of a two phase interleaved critical mode PFC regulator is developed. With this new closed loop interleaving method, both two phase converters are working at the boundary between continuous and discontinuous mode and accurate 180 degree phase shift is achieved. Implementation of this strategy could be easily integrated to the control chip.