LM5020

100V Current Mode PWM Controller

General Description

The LM5020 high voltage pulse-width-modulation (PWM)

controller contains all of the features needed to implement

single ended primary power converter topologies. Output

voltage regulation is based on current-mode control, which

eases the design of loop compensation while providing in-

herent line feed-forward. The LM5020 includes a high-

voltage start-up regulator that operates over a wide input

range up to 100V. The PWM controller is designed for high

speed capability including an oscillator frequency range to

1MHz and total propagation delays less than 100ns. Addi-

tional features include an error amplifier, precision reference,

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

compensation, softstart, oscillator synchronization capability

and thermal shutdown. The controller is available in both

MSOP-10 and LLP-10 packages.

Features

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Internal Start-up Bias Regulator

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Error Amplifier

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Precision Voltage Reference

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Programmable Softstart

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1A Peak Gate Driver

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Maximum Duty Cycle Limiting (80% for LM5020-1 or

50% for LM5020-2)

n

Programmable Line Under Voltage Lockout (UVLO) with

Adjustable Hysteresis

n

Cycle-by-Cycle Over-Current Protection

n

Slope Compensation (LM5020-1)

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Programmable Oscillator Frequency with

Synchronization Capability

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Current Sense Leading Edge Blanking

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Thermal Shutdown Protection

Applications

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Telecommunication Power Converters

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Industrial Power Converters

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+42V Automotive Systems

Packages

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MSOP-10

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LLP-10 (4 mmx4mm)

Typical Application Circuit

20095013

Non-Isolated Flyback Converter

April 2006

© 2006 National Semiconductor Corporation

DS200950

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