1. Technical Field
The disclosure relates to a power-factor-corrected converter, and more particularly to a power-factor-corrected resonant converter and a parallel power-factor-corrected resonant converter.
2. Related Art
Generally, most conventional circuits for power factor correction (PFC) employ an inductor as an energy-storage element and employ a boost control topology for correcting power factor and transferring the energy to a load. Therefore, the material of the core of the inductor should be taken into consideration in order to avoid large hysteresis loss caused by pulse current. Furthermore, the size of the circuit is increased by using the inductor as an energy-storage element.
In order to maintain the stability of the boost control topology, additional compensation capacitors and complicated control circuit including circuit element such as an analog multiplier, are required to achieve the power factor correction. Furthermore, in the above mentioned circuit, other circuit elements having functions of frequency jitter, quasi resonant or valley switching are also included in the clock control signals in order to reduce the generation of electromagnetic interference (EMI).
Furthermore, because the boost control typology is employed for power factor correction, the output voltage in the circuit will be boosted to a higher voltage level such as 600V. Therefore, switching elements (e.g. elements with a maximum rating Drain-Source voltage above 600V) which can resist high voltage should be employed in the circuit. Accordingly, circuits for power factor correction are still required to be improved.