Single Cycle High Efficiency PFC Design Based On BOOST Structure

With the continuous development of power electronics technology, more and more non-linear electronic devices are added to the grid system which causes serious pollution to the grid system. An increase in harmonics and reactive power, on one hand, increases the energy demand from the grid system; on the other hand, affects the safety and reliability of other electrical equipment. In order to ensure the security and stability of the grid system and to improve the power factor(PF) of electrical equipment, a large number of countries and organizations have issued a series of standards related, which has been forced to carried out.This paper has designed a chip with power factor correction, which is suitable for boost(BOOST) topology. The design of this chip is based on the one-cycle control(OCC) principle, having simple structure and few external devices. The chip operates in continuous current mode(CCM), and in each cycle, the inductor current changes continuously.In detail, this paper analyzes the principle of one-cycle control and its different implementation method. The design uses later-edge modulation method and makes a detailed introduction of the internal structure of the chip. The external voltage loop stables the output voltage, generates a sawtooth waveform for internal comparison and adjusts the magnitude of the input current through nonlinear module. The inner current loop shapes the input current, forces the current follow the phase of the input voltage, generates a voltage reference for internal comparison.This paper makes a design and simulation of the major internal circuits including oscillator circuit, gate-drive circuit, fast dynamic response circuit, high speed comparator circuit, protection circuits and does a detailed introduction of the external topology circuit. Based on CSMC’s 0.5um 25 V BCD process, we make a simulation of the overall circuit. With load of 300 W and power of 220 Vac, the measured PF is 0.983, the THD 16.2%, the η96.9%, which achieves the purpose of high efficiency and high PF.