基于LT3575的隔離反激型電源轉換技術設計

本文介紹了LT3575主要特性，方框圖以及多種單輸出，雙輸出和四輸出隔離轉換器電路圖。Linear 公司的LT3575是用于隔離反激拓撲的開關電源穩壓器，不需要第三個繞組或光隔離器。輸入電壓3-40V，集成了2.5A/60V NPN功率開關，輸出功率可高達14W，主要應用在工業，汽車和醫療設備的隔離電源。

Isolated Flyback Converter without an Opto-Coupler

The LTR3575 is a monolithic switching regulator specifically designed for the isolated flyback topology. No third winding or optoisolator is required for regulation. The part senses the isolated output voltage directly from the primary side flyback waveform. A 2.5A, 60V NPN power switch is integrated along with all control logic into a 16-lead TSSOP package.

The LT3575 operates with input supply voltages from 3V to 40V, and can deliver output power up to 14W with no external power switch. The LT3575 utilizes boundary mode operation to provide a small magnetic solution with improved load regulation.

The output voltage is easily set with two external resistors and the transformer turns ratio. Off the shelf transformers are available for many applications.

LT3575主要特性:

3V to 40V Input Voltage Range

2.5A, 60V Integrated NPN Power Switch

Boundary Mode Operation

No Transformer Third Winding or Optoisolator Required for Regulation

Improved Primary-Side Winding Feedback Load Regulation

VOUT Set with Two External Resistors

BIAS Pin for Internal Bias Supply and Power NPN Driver

Programmable Soft-Start

Programmable Power Switch Current Limit

Thermally Enhanced 16-Lead TSSOP

LT3575應用:

Industrial, Automotive and Medical Isolated Power Supplies

圖1。LT3575方框圖

圖2。LT3575低輸入電壓5V隔離反激轉換器電路圖

圖3。LT3575 +/-12V隔離反激轉換器電路圖

圖4。LT3575 5V隔離反激轉換器電路圖