CET Technology designs and manufactures PFC inductors for any application. As a general rule, higher current ratings and higher inductance values mean a larger and more expensive inductor.
Design input parameters include:
• Target inductance
• Max DC current
• Desired ripple current
• Peak operating voltage
• Power rating
Alternatively, based on the chip set being used, CET can work with the designer to determine the optimum PFC inductor for your application.
Power factor is related to the phase difference between the voltage and current on a particular load. If the voltage and current are perfectly in phase (i.e. purely real load impedance,) the power factor is 1.0. However, if the load is inductive or capacitive, it introduces a phase difference between voltage and current and the power factor will be less than 1.0.
Switching power supplies present a nonlinear impedance to the AC line, so they always have a power factor less than 1.0. Therefore, many switching power supplies are designed with an active Power Factor Correction (PFC) stage.
There are three main control methods for active PFC circuits: Continuous Conduction Mode (CCM); Discontinuous Conduction Mode (DCM); and Boundary Conduction Mode (BCM), also sometimes known as Critical Conduction Mode (CRM.) Regardless of which control method is used, the PFC stage always includes a PFC inductor. The different conduction modes refer to whether or not the inductor current drops to 0A during a switching cycle.