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® APPLICATION NOTE DESIGNING A HIGH POWER FACTOR SWITCHING PREREGULATOR WITH THE L6560/A TRANSITION MODE I.C. by G. Comandatore and U. Moriconi Active power factor correction techniques are going to grow in conversion applications. Market interest (legislation to be considered) is also moving towards fairly low (36-150W) conversion power ranges (lighting, monitor). This paper describes an "easy to use" 8 Pin Controller that allows the realization of very low cost offline Power Factor Correction. Switching at a frequency much higher than the line, the preregulator draws a half-sinusoidal input current, in phase with the line voltage. BOOST TOPOLOGY with its inductor at the input is well suited for PFC application. The input di/dt is low because the inductor is located between the bridge and the switch. This minimizes line noise and, in addition, the line spikes can be absorbed by the Boost Inductor. L6560/A PFC controller Integrated Circuit The L6560/A is an integrated circuit in Minidip and SO8 packages designed to perform the control of active power factor correction circuits. The I.C. is optimized for electronic ballast, but it can be easily used in switched mode AC-DC conversion. It can directly drive Mosfet or Igbt (see block diagram fig.1). Introduction Conventional AC to DC converters employ a full wave rectifier bridge with a simple capacitor filter to draw DC power from the mains AC. This filter capacitor must be large enough to supply the total power during most ...