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
SO8 package

Application
PFC pre-regulators for:
– IEC61000-3-2 and JEIDA-MITI compliant SMPS in excess of 1 kW
– Desktop PC, server, web server, game console
– High power LED luminaries

Description
The L4985 is a peak current-mode PFC controller for boost converter with a
proprietary multiplier “emulator” which in addition to the innovative THD optimizers
guarantee very low Total Harmonic Distortion (THD) performance in all operating
conditions. The device comes in a pin SO package and offers a high performance/
low-component count solution for CCM-operated boost PFC pre-regulators in
EN61000-3-2 and JEIDA-MITI compliant applications, in a power range that spans
from few hundred W to some kW.
The device, thanks to a proprietary off-time modulator, operates in quasi-fixed
frequency in all operating conditions. Two options are available, 65 kHz for A and
130 kHz for B.
The 800V high voltage start-up block includes also the circuitry to discharge the
X-capacitors of the EMI filter to a safe level. This allows the unit to meet safety
regulation (such as IEC 61010-1 or IEC 62368-1) without using the traditional
discharge resistor in parallel to the X-capacitors.
The device features low consumption and disable functions allowing usage in
applications supposed to comply even with 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.
– Industrial and medical SMPS according to IEC 60601-1-2