基于LT3575的隔离反激型电源转换技术设计

本文介绍了LT3575主要特性，方框图以及多种单输出，双输出和四输出隔离转换器电路图。Linear 公司的LT3575是用于隔离反激拓扑的开关电源稳压器，不需要第三个绕组或光隔离器。输入电压3-40V，集成了2.5A/60V NPN功率开关，输出功率可高达14W，主要应用在工业，汽车和医疗设备的隔离电源。

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应用:

Industrial, Automotive and Medical Isolated Power Supplies

图1。LT3575方框图

图2。LT3575低输入电压5V隔离反激转换器电路图

图3。LT3575 +/-12V隔离反激转换器电路图

图4。LT3575 5V隔离反激转换器电路图


图5。LT3575 3.3V隔离反激转换器电路图

图6。LT3575 12V隔离反激转换器电路图


图7。LT3575 四输出12V隔离反激转换器电路图