Critical Conduction Mode Control Pfc Chip Analysis And Design

The power factor is an important parameter that characterizes electrical equipment. With the desire for higher quality power supply, the technology of power factor correction has been developing rapidly. A lot of approach can be used for correction from the active to the inactive correction. The inactive power factor correction is adopted by less equipment for its drawback of weight and magnitude. There are two modes for the active correction. One is continuous conduction mode which is used in the high power for its small ripple current. Another is discontinuous mode which has a wide application in the low power for its simple control circuit.A variety of control chip of the power factor correction has been designed and fabricated with the development of the technology of microelectronics. ST, ONSEMI and Microlinear all have correction chip in market. The technology and control circuits of correction have become an important topic with the prosperity of microelectronics technology, because of lack of energy storage in our country.Following the hot topic of power factor correction in this article, the basic concept was analyzed firstly. With this, the control theory of power factor correction will be discussed next. The principle of critical conduction mode will be analyzed with the theory. The element of critical conduction mode control circuit will be analyzed and designed then. Layout design of circuit will be given finally.