Features

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Peak current mode CCM-operated

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800 V high voltage startup with integrated input voltage sensing

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Active input filter capacitor discharge

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Proprietary multiplier “emulator” with minimum THD of line current in all

operating conditions (CCM and DCM)

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Extremely few external components

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Protections: feedback loop failure, OVP, OCP, inductor saturation, brown-in,

brownout (compliant to medical SMPS standards)

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Inductor current sense

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Disable and low consumption function

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In-rush current monitoring

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Soft-start for smooth startup

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1.2% (@ Tj = 25 °C) internal reference voltage

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65 kHz (A version) and 130 kHz (B version) switching frequency

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SO8 package

Application

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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

–

Industrial and medical SMPS according to IEC 60601-1-2

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.

Product status link

L4985

L4985A

L4985B

L4985ATR

L4985BTR

Product summary

Order

codes

Package

Packaging

L4985A

SO-8

Tube

L4985B

Tube

L4985ATR

Tape and

reel

L4985BTR

Tape and

reel

CCM PFC controller with high voltage startup

L4985

Datasheet

DS13769 - Rev 3 - January 2022

For further information contact your local STMicroelectronics sales office.

www.st.com