原标题：Linear LTC3787多相单输出升压电源转换方案

　　Linear公司的LTC3787是高性能多相单输出同步升压电源转换器控制器, 能驱动两个N沟功率MOSFET.输入电压4.5V-38V,输出电压高达60V,±1% 1.200V基准电压, 可编程固定频率50kHz到900kHz,静态电流135uA,主要用于工业,汽车,医疗设备和军用.本文介绍了LTC3787主要特性,方框图, 12相工作连接图以及高效2相24V,46V和48V升压转换器电路图, 4相单输出升压转换器电路图,演示板DC1411A主要性能特性,电路图,材料清单和PCB元件布局图.

　　The LTC3787 is a high performance PolyPhase single output synchronous boost converter controller that drives two N-channel power MOSFET stages out-of-phase. Multiphase operation reduces input and output capacitor requirements and allows the use of smaller inductors than the single-phase equivalent. Synchronous rectification increases efficiency, reduces power losses and eases thermal requirements, enabling high power boost applications.

　　A 4.5V to 38V input supply range encompasses a wide range of system architectures and battery chemistries. When biased from the output of the boost converter or another auxiliary supply, the LTC3787 can operate from an input supply as low as 2.5V after start-up. The operating frequency can be set for a 50kHz to 900kHz range or synchronized to an external clock using the internal PLL.

　　PolyPhase operation allows the LTC3787 to be configured for 2-, 3-, 4-, 6- and 12-phase operation.

　　The SS pin ramps the output voltage during start-up. The PLLIN/MODE pin selects Burst Mode. operation, pulseskipping mode or forced continuous mode at light loads.

　　LTC3787主要特性:

　　2-Phase Operation Reduces Required Input and Output Capacitance and Power Supply Induced Noise

　　Synchronous Operation for Highest Efficiency and Reduced Heat Dissipation

　　Wide VIN Range: 4.5V to 38V (40V Abs Max) and Operates Down to 2.5V After Start-Up

　　Output Voltage Up to 60V

　　±1% 1.200V Reference Voltage

　　RSENSE or Inductor DCR Current Sensing

　　100% Duty Cycle Capability for Synchronous MOSFET

　　Low Quiescent Current: 135μA

　　Phase-Lockable Frequency (75kHz to 850kHz)

　　Programmable Fixed Frequency (50kHz to 900kHz)

　　Power Good Output Voltage Monitor

　　Low Shutdown Current, IQ < 8μA

　　Internal LDO Powers Gate Drive from VBIAS or EXTVCC

　　Thermally Enhanced Low Profile 28-Pin 4mmx 5mm

　　QFN Package and Narrow SSOP Package

　　LTC3787应用:

　　Industrial

　　Automotive

　　Medical

　　Military

　　图1.LTC3787方框图

　　图2.LTC3787 12相工作连接图

　　图3.LTC3787高效2相24V升压转换器电路图

　　图4.LTC3787高效2相48V升压转换器电路图

　　图5.LTC3787高效2相36V升压转换器电路图

　　图6.LTC3787高效2相48V升压转换器电路图

　　图7.LTC3787采用电感DCR电流检测的高效2相24V升压转换器电路图

　　图8.LTC3787 4相单输出升压转换器电路图

　　演示板DC1411A主要性能特性: