《电子技术应用》

LinearLT8582故障保护双路PWMDC电源解决方案

作者:Linear公司
2012/2/1 14:10:17

Linear公司的LT8582是带故障保护的双路独立的PWM DC/DC转换器,每路包括42V主开关和42V从开关,并联使用的总电流为3A,具有过压,超温以及输出短路保护.工作电压2.5V-22V,开关频率高达2.5MHz,每路可容易配置成升压,SEPIC,反向或反激转换器,主要用在本地电源,VFD偏压电源,TFT-LCD偏压电源和汽车引擎控制单元(ECU)电源.本文介绍了LT8582主要特性,方框图,基本应用电路以及多种典型应用电路与两种拓扑的元件布局图.

The LT8582 is a dual independent channel PWM DC/DC converter with a power good pin and built-in fault protection to help guard against input overvoltage and overtemperature
conditions. Each channel consists of a 42V master switch and a 42V slave switch that can be tied together for a total current limit of 3A.

The LT8582 is ideal for many local power supply designs. Each channel can be easily configured in boost, SEPIC, inverting, or flyback configurations. Together, the two channels can produce a 12V and a –12V output with 14.4W of combined output power from a 5V input. In addition, the LT8582’s slave switch allows the part to be configured in
high voltage, high power charge pump topologies that are more efficient and require fewer components than traditional circuits.

The LT8582 also features innovative SHDN pin circuitry that allows for slowly varying input signals and an adjustable undervoltage lockout function. Additional features such as
output short protection, frequency foldback and soft-start are integrated. The LT8582 is available in a 24-pin 7mmx 4mm DFN package.

LT8582主要特性:

Dual 42V, 3A Combined Power Switch

Master/Slave (1.7A/1.3A) Switch Design

Wide Input Range: 2.5V to 22V Operating, 40V Maximum Transient

Power Good Pin for Event Based Sequencing

Switching Frequency Up to 2.5MHz

Each Channel Easily Configurable as a Boost, SEPIC, Inverting or Flyback Converter

Low VCESAT Switch: 270mV at 2.75A (Typical)

Can be Synchronized to an External Clock

Output Short-Circuit Protection

High Gain SHDN Pin Accepts Slowly Varying Input Signals

24-Pin 7mmx 4mm DFN Package

LT8582应用:

Local Power Supply

Vacuum Fluorescent Display (VFD) Bias Supplies

TFT-LCD Bias Supplies

Automotive Engine Control Unit (ECU) Power

图1. LT8582方框图

图2. LT8582升压转换器电路图:1.5MHz,5V到12V升压

图3. LT8582 SEPIC转换器电路图:700kHz,3V-19V到5V SEPIC拓扑

图4. LT8582双电感反向转换器电路图:1.5MHz,5V到-12V反向电压

图5. LT8582高VOUT电荷泵拓扑电路图

图6. LT8582 5V到+/-12V升压和反向电压电路图

图7. LT8582 VFD和灯丝电源电路图:1MHz开关频率

图8. LT8582 2.7V-5.5V输入+/-15V输出电路图

图9. LT8582超大电容备份电源电路图

图10. LT8582 3-19V输入12V和15V顺序输出电路图

图11. LT8582升压和双电感反向电源拓扑元件布局图

图12. LT8582 SEPIC和双电感反向电源拓扑元件布局图
详情请见:
http://cds.linear.com/docs/Datasheet/8582f.pdf



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