Linear LTC3787多相单输出升压电源转换方案

发布时间：2012-6-26 09:45 发布者：1770309616

关键词： Linear , LTC3787 , 电源

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:

图9.演示板DC1411A电路图:输入5-24V,输出24V/6A
演示板DC1411A材料清单:


Qty	Reference		Part Description	Manufacturer / Part #

		REQUIRED CIRCUIT COMPONENTS:

3	CIN1,COUT5,COUT10		CAP., 150uF,35V,EP-cap	SUNCON, 35HVH150M
12	COUT1, COUT2, COUT3, COUT4, COUT6, COUT7, COUT8, COUT9, CIN2, CIN3, CIN4, CIN5		Cap.,X5R, 22uF 25V, 20%,1812	TDK, C4532X5R1E226M
1	C2,		Cap., NPO, 100pF, 25V,10%,0603	AVX, 06033A101KAT
1	C3		Cap.,X7R, 15nF, 25V, 10%,0603	AVX, 06033C153KAT
4	C4,C9,C15,C16		Cap., X5R, 0.1uF, 25V, 10%, 0603	AVX, 06033D104KAT2A
3	C5,C10,C18		Cap., NPO, 1000pF, 25V,10%,0603	AVX, 06033A102KAT
1	C8		Cap., X5R, 4.7uF, 25V, 10%,0805	TaiyoYuden, TMK212BJ475KG-T
2	D1,D2		DIODE, 30V, SOD323	Infineon, BAS140W
2	L1,L2		Inductor, 3.3uH	PULSE-PA1494.362NL
2	Q2,Q8		MOSFET,N Chanel,LFPAK	RENESAS, RJK0452DPB
2	Q4,Q6		MOSFET,N Chanel,LFPAK	RENESAS, RJK0453DPB
4	RSNS1,RSNS2,RSNS3,RSNS4		Res., Chip, 0.008, 1%, 2010	VISHAY, WSL20108L000FEA
6	R2,R3,R5,R7,R15,R18		Res., Chip, 0 Ohm, 1%, 0603	VISHAY, CRCW06030000Z0EA
1	R6		Res., Chip, 232K, 1%, 0603	VISHAY, CRCW0603232KFKED
3	R8,R9,R34		Res., Chip, 12.1K, 1%, 0603	VISHAY, CRCW060312K1FKEA
4	R11,R16,R35,R36		Res., Chip, 10K, 1%, 0603	VISHAY, CRCW060310KFKEA
4	R13,R17,R19,R21		Res., Chip, 10, 1%, 0603	VISHAY, CRCW060310R0FKEA
2	R26,C17		Res., Chip, 100K, 1%, 0603	VISHAY, CRCW0603100KFKEA
1	R32		Res., Chip, 2.21, 1%, 0603	VISHAY, CRCW06032R21FNEA
1	R33		Res., Chip, 38.3K ,1%, 0603	VISHAY, CRCW060338K3FKEA
1	U1		I.C. LTC3787EUFD QFN28 - 4X5	Linear Tech.,LTC3787EUFD


		ADDITIONAL DEMO BOARD CIRCUIT COMPONENTS:

0	C1,C19,C20		OPT, 0603
0	Q1,Q3,Q5,Q7		OPT, LFPAK
0	R1,R4,R10,R31		OPT, 0603


		HARDWARE-FOR DEMO BOARD ONLY:

11	E1,E5,E6,E7,E8,E11, E12,E13,E14,E15,E21		Turret, Testpoint , 091"	Mill Max 2501-2-00-80-00-00-07-0
2	E2,E4		JACK BANANA	KEYSTONE, 575-4
2	E9,E10		STUD, TEST PIN	PEM KFH-032-10
4	(E9,E10)X2		NUT, BRASS NUTS # 10-32	ANY #10-32
2	E9,E10		RING, LUG RING # 10	KEYSTONE #10
2	E9,E10		WASHER, TIN PLATED BRASS	ANY #10
2	JP1,JP5		Headers, 4 Pins 2mm Ctrs.	Samtec TMM-104-02-L-S
1	JP2		Headers, 3 Pins 2mm Ctrs.	Samtec TMM-103-02-L-S
4	XJP1-XJP2		Shunt, 2mm Ctrs.	Samtec 2SN-BK-G
4			STAND-OFF, NYLON 0.5" tall	KEYSTONE, 8833(SNAP ON)