Describes the design of a high power factor switching preregulator
The document describes the operation of the L4981 integrated circuit, which is a continuous mode average current controller for active power factor correction. It details how the device improves power factor to up to 0.99 by drawing sinusoidal input current in phase with line voltage using a boost topology.
The preregulator can improve the power factor up to 0.99.
The device allows for a switching frequency higher than 200 kHz.
The overvoltage protection comparator uses a precise 5.1V reference voltage.