STMicroelectronics — L4986 PFC Power Controller

The L4986 from STMicroelectronics is a boost power factor correction (PFC) controller which offers high performance and a reduced component count in EN61000-3-2 and JEIDA-MITI-compliant applications. The controller, which is intended for operation in continuous current mode (CCM), supports systems with a power output ranging between 500 W and several kilowatts.

The L4986 features a proprietary multiplier emulator alongside total harmonic distortion (THD) optimizers. Together, they produce very low THD in all operating conditions. The device switches at a quasi-fixed frequency at one of two speeds, either 65 kHz or 130 kHz.

An 800 V high-voltage start-up block includes circuitry for discharging the X-capacitors of the EMI filter to a safe level. This allows the unit to meet safety regulations such as IEC 61010-1 or IEC 62368-1 without the need for a discharge resistor in parallel to the X-capacitors.

Integrated protection functions include brown-out protection to support the development of power supplies for medical equipment. This feature is compatible with the latest regulations imposed by the IEC 60601-1-2 standard, which requires output regulation in the event of mains power dips lasting up to 500 ms.

Low power-consumption and disable functions allow usage in applications that are required to comply with the latest energy-saving regulations and directives in the US or the European Union.