VOUT

VIN

CS

SS

OUT

FEEDBACK

WITH

ISOLATION

COMP

GND

RT

VCC

LM5021

90 ~ 264 Vac

+

+

AC

LM5021

www.ti.com

SNVS359D – MAY 2005 – REVISED MARCH 2013

LM5021 AC-DC Current Mode PWM Controller

Check for Samples: LM5021

1

FEATURES

DESCRIPTION

The LM5021 off-line pulse width modulation (PWM)

2

•

Ultra Low Start-up Current (25 µA maximum)

controller contains all of the features needed to

•

Current Mode Control

implement

highly

efficient

off-line

single-ended

•

Skip Cycle Mode for Low Standby Power

flyback and forward power converters using current-

mode control. The LM5021 features include an ultra-

•

Single Resistor Programmable Oscillator

low (25 µA) start-up current, which minimizes power

•

Synchronizable Oscillator

losses in the high voltage start-up network. A skip

•

Adjustable Soft-Start

cycle mode reduces power consumption with light

loads for energy conserving applications (ENERGY

•

Integrated 0.7A Peak Gate Driver

STAR®, CECP, etc.). Additional features include

•

Direct Opto-Coupler Interface

under-voltage lockout, cycle-by-cycle current limit,

•

Maximum Duty Cycle Limiting (80% for

hiccup

mode

overload

protection,

slope

com-

LM5021-1 or 50% for LM5021-2)

pensation, soft-start and oscillator synchronization

capability. This high performance 8-pin IC has total

•

Slope Compensation for (LM5021-1 Only)

propagation delays less than 100nS and a 1MHz

•

Under Voltage Lockout (UVLO) with Hysteresis

capable oscillator that is programmed with a single

•

Cycle-by-Cycle Over-Current Protection

resistor.

•

Hiccup Mode for Continuous Overload

WHITE SPACE

Protection

•

Leading Edge Blanking of Current Sense

Signal

•

Packages: VSSOP-8 or PDIP-8

Simplified Application Diagram

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2005–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.