| IR 公司的IR3640是高效高性能PWM降压电源控制器,外部电源4.5V到5.5V,输入电压从1.5V到24V,输出电压从0.7V到0.9xVin,开关频率可高达1.5MHz,可编程软起动,采用Rds(on)检测的打嗝模式过流保护,可编程OCP,具有增强的预偏置起动,输出电压跟踪,可用于点负载电源架构,服务器和网络设备,游戏机和通用DC/DC转换器.本文介绍了IR3640的主要特性,方框图, 顺序加电应用电路,以及25A, 600kHz同步降压控制器参考设计和材料清单. HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER The IR3640M is a synchronous Buck PWM controller designed for performance demanding DC/DC applications. The single loop voltage mode architecture simplifies design while delivery precise output voltage regulation and fast transient response. Because of its wide input and output voltage range it can be used in a large variety of point of load applications within a system and across different markets. The part is designed to drive a pair of N-Channel MOSFETs from 250kHz to 1.5Mhz switching frequency giving designers the flexibility to optimize the solution for best efficiency or smallest footprint. The output voltage can be precisely regulated from as low as 0.7V within a tolerance of +/-1% over temperature, line and load variations. The device also integrates a diversity of features including; programmable soft start, pre-bias start up, voltage tracking, external synchronization, enable input and Power Good output. Fault protection features include thermal shutdown, over voltage and over current shutdown and under voltage lock out. IR3640主要特性: 4.5V to 5.5V external supply Wide Input voltage from 1.5V to 24V Output voltage range: 0.7V to 0.9*Vin Programmable switching frequency up to 1.5MHz Programmable Soft-start Hiccup mode over current protection using Rds(on) sensing Programmable OCP Reference voltage 0.7V (+/-1%, 0℃ Enhanced Pre-bias start up Output voltage tracking Integrated MOSFET drivers and bootstrap diode Operating temp: -40℃ External synchronization Power Good output Thermal shut down Over voltage protection Enable Input with voltage monitoring capability Pb-Free & Halogen-Free (RoHS Compliant) 20 -Lead MLPQ package (3mmx4mm) IR3640应用: Point of Load Power Architectures Server & Netcom Applications Game Consoles General DC/DC Converters  图1.IR3640简化方框图  图2.IR3640顺序加电应用电路  图3.IR3640典型应用电路:12-18V,25A点负载转换器 应用电路材料清单(BOM):   图4.IR3640典型顺序加电应用电路 IR3640 评估板:25A, 600kHz, 同步降压控制器参考设计  The IR3640 is a PWM controller for use in high performance synchronous Buck DC/DC applications. This is designed to drive a pair of external NFETs using a programmable switching frequency up to 1.5MHz in voltage mode. It is housed in a in 20 Lead 3x4 MLPQ package. Key features offered by the IR3640 include programmable soft-start ramp, Power Good, thermal protection, over voltage and over current protection, programmable switching frequency, tracking input, enable input, input under-voltage lockout for proper start-up, and pre-bias start-up. An output over-current protection function is implemented by sensing the voltage developed across the on-resistance of the synchronous rectifier MOSFET for optimum cost and performance. This user guide contains the schematic and bill of materials for the IR3640 evaluation board. The guide describes operation and use of the evaluation board itself. Detailed application information for IR3640 is available in the IR3640 data sheet.  图5. IR3640评估板电路图 IR3640评估板材料清单(BOM):  |
