The L4985A from STMicroelectronics is a Peak Current-Mode PFC Controller IC that is designed for boost converters with a proprietary multiplier “emulator” and innovative THD optimizers that guarantee very low Total Harmonic Distortion (THD) performance in all operating conditions. It requires an input voltage of up to +30 V. This PMIC utilizes STMicroelectronics’ proprietary off-time modulator and operates at a quasi-fixed frequency in all operating conditions. It integrates circuitry to discharge the X-capacitors of the EMI filter to a safe level, thereby allowing the unit to meet the safety regulations (such as IEC 61010-1 or IEC 62368-1) without connecting the traditional discharge resistor in parallel with the X-capacitors. The PFC controller offers low consumption and disabled functions that allow it to be used in applications that are supposed to comply with even the latest energy-saving requirements issued by Energy Star, the Department of Energy (DoE) in the United States, the European Code of Conduct, the European Union's Ecodesign Directive, and other guidelines.

The L4985A offers feedback loop failure, inductor saturation, brown-in, brownout, over-voltage (OVP), and over-current protection (OCP) to prevent erroneous settings or short-circuit-related damages. This PFC controller IC is available in a surface-mount package that measures 5.0 x 6.2 x 1.75 mm and is ideal PFC pre-regulators for IEC61000-3-2 and JEIDA-MITI compliant SMPS over 1 kW, PFC pre-regulators for desktop PC, server, web server, game console, PFC pre-regulators for high power LED luminaries, PFC pre-regulators for industrial and medical SMPS applications.