Continuous conduction mode (CCM) PFC controller with high-voltage startup and adjustable power good function


Based on a fixed-off-time (FOT) control technique, the L4986 includes proprietary circuitries able achieve the same performance as more complex/expensive current mode controllers.

A high-performance, low-component count solution for CCM-operated boost PFC pre-regulators in EN61000-3-2 and JEIDA-MITI compliant applications, the L4986 simplifies designs and enhances flexibility by integrating 800V startup circuitry and additional valuable proprietary features.

Key features

  • Peak current mode CCM-operated
  • 800 V high voltage startup with integrated input voltage sensing
  • Active input filter capacitor discharge
  • Proprietary multiplier emulator with minimum THD of line current in all operating conditions (CCM and DCM)
  • Extremely few external components
  • Protections: feedback loop failure, OVP, OCP, inductor saturation, brown-in, brownout (compliant to medical SMPS standards)
  • Inductor current sense
  • Disable and low consumption function
  • In-rush current monitoring
  • Soft-start for smooth startup
  • 1.2% (@ Tj = 25 °C) internal reference voltage
  • 65 kHz (A version) and 130 kHz (B version) switching frequency
  • PGOOD_OUT and adjustable PGOOD_IN
  • SSOP10 package

Application examples

PFC pre-regulators for:

smps IEC61000-3-2 and JEIDA-MITI compliant SMPS in excess of 1 kW
desktop Desktop PC, server, web server, game console
led lighting High power LED luminaries
smps Industrial and medical SMPS according to IEC 60601-1-2

Recommended resources


Suitable for SMPS designs from 150 W to several kW, the design features very low input current distortion (THD) in all operating conditions, and highly limited number of external components, as the high-voltage start-up circuit and the X-cap discharge circuits are embedded in the L4986.


Based on a double-boost (Barbi) topology, the board offers high efficiency and low input current THD across the entire input voltage range thanks to a low-complexity schematic and fewer components compared to similar bridgeless solutions.