This document presents a solution for designing a transition mode PFC preregulator using the L6562A. The L6562A is the latest proposal from STMicroelectronics for low and middle power applications such as lamp ballasts, high-end adapters, flat TVs and monitors, and PC power supplies. It is also suitable for emerging markets that may require low-cost power factor correction. Based on a well-established architecture, the L6562A offers excellent performance that considerably enlarges its field of application.