|ON Semiconductor's NCP1611 is an active Power Factor Corrected (PFC) controller specifically designed for use as a boost pre-converter in AC-DC adapters, flat TVs, lighting ballasts, and other medium powered offline applications. The controller is based on an innovative Current Controlled Frequency Foldback (CCFF) method. In this mode, the circuit classically operates in Critical conduction Mode (CrM) when the inductor current exceeds a programmable value. When the current is below this preset level, the device linearly reduces the frequency down to 20 kHz when the current is at a null. CCFF maximizes the efficiency at both nominal and light loads. In particular, the standby losses are reduced to a minimum. The controllers feature a robust suite for protection features to properly handle an array of power supply operating and fault conditions.