High-end TV and Monitor Switch-Mode Power Supplies (200-500W) commonly implement interleaved (two phase) critical conduction mode (CrCM, also called Transition mode-TM) PFC (Power Factor Correction) block, to improve efficiency and reduce design volume (height). This application note describes how to achieve higher efficiency to reduce power loss further and alleviate thermal challenge at low AC line condition without topology and power stage change. A simple external circuit is introduced here and the working principle is elaborated. Measurement shows 1-2% efficiency boost depending on the load conditions.