Linear LTC7821混合降压同步电源转换解决方案

Linear公司的LTC7821是混合降压同步电源转换控制器,把软开关电荷泵拓扑和同步降压转换器组合起来,提供高达97%的效率和更好的EMI性能,VIN输入电压10V-72V,可锁相固定频率200kHz到1.5MHz,输出电压精度±1%,可编CCM,DCM或突发模式工作,主要用在中间总线转换,大电流分布电源系统,通信,数据通信和存储系统.本文介绍了LTC7821主要特性,框图,应用电路,以及演示板DC2513A主要指标,测量建立图,电路图和材料清单.
The LTC®7821 uses a proprietary architecture that mergesa soft switching charge pump topology with a synchronousstep-down converter to provide superior efficiencyand EMI performance compared to traditional switchingarchitectures.
In a typical 48V to 12V application, efficiency of greaterthan 97% is attainable with the LTC7821 switching at500kHz. The same efficiency can only be achieved with atraditional controller switching at one-third the frequency.
Higher switching frequencies allow the use of smaller inductancesthat yield faster transient response and smallersolution size.
The LTC7821 can be easily paralleled to provide higheroutput currents with its accurate current sharing capabilityand frequency synchronization function.
LTC7821主要特性:
Wide VIN Range: 10V to 72V (80V ABS Max)
Soft Switching for Low Noise Operation
Phase-Lockable Fixed Frequency 200kHz to 1.5MHz
±1% Output Voltage Accuracy
RSENSE or DCR Current Sensing
Programmable CCM, DCM, or Burst Mode® Operation
CLKOUT Pin for Multiphase Operation
Short Circuit Protected
EXTVCC Input for Improved Efficiency
Monotonic Output Voltage Start-Up
Optional External Reference
32-Pin (5mm × 5mm) QFN
LTC7821应用:
Intermediate Bus Converters
High Current Distributed Power Systems
Telecom, Datacom, and Storage Systems

图1.LTC7821框图

图2.LTC7821应用电路图(1)

图3.LTC7821应用电路图(2):500kHz,48V/9V,20A降压转换器
演示板DC2513A
Demonstration circuit 2513A is a high efficiency, highpower density hybri...