Linear LTC3125可编输入限流升压稳压方案

Linear公司的LTC3125是1.2A 1.6MHz同步升压稳压器,提供输出断开和可编输入限流,限流精度在±5%,编程范围从200mA到1000mA,限流采用电阻编程,以适应多种应用.输入电压从1.8V到5.5V,输出电压从2V到5.25V,固定开关频率1.6MHz,效率高达93%.具有软起动和关断是输出断开特性. LTC3125广泛用在GSM/GPRS PCMCIA/CompactFlash PC卡调制解调器,无线紧急状态定位仪,手提无线电和超大电容充电器.本文介绍了LTC3125的主要特性,方框图以及多种应用电路图.

LTC3125: 1.2A, 1.6MHz Synchronous Boost Regulator Offers Output Disconnect & Programmable Input Current Limit

The LTC3125 is a high efficiency, synchronous step-up DC/DC converter with an accurate programmable average input current limit. The ±5% accurate average input current is resistor programmable and suitable for a wide variety of applications. In mobile computing, GSM and GPRS cards demand high current pulses well beyond the capability of the PC Card and CompactFlash slots. The LTC3125 in concert with a reservoir capacitor, keeps the slot power safely within its capabilities providing a high performance
and simple solution.

Synchronous rectification produces high efficiency while the 1.6MHz switching frequency minimizes the solution footprint. The current mode PWM design is internally compensated.
Output disconnect allows the load to discharge in shutdown, while also providing inrush current limiting. Other features include a <1μA shutdown current, shortcircuit and thermal overload protection. The LTC3125 is offered in a low profile 0.75mmx&#61472;2mmx&#61472;3mm package.

LTC3125主要特性:
Programmable Average Input Current Limit
5% Input Current Accuracy
200mA to 1000mA Program Range
VIN: 1.8V to 5.5V, VOUT: 2V to 5.25V
Supports High Current GSM/GPRS Load Burst
VIN > VOUT Operation
1.6MHz Fixed Frequency Operation
Internal Current Sense Resistor
1.2A Peak Current Limit
Up to 93% Effi ciency
Output Disconnect in Shutdown
Soft-Start
Low Quiescent Current Burst Mode  Operation (15μA)
Available in 2mm &#61655;&#61472;3mm &#61655;&#61472;0.75mm DFN Package
LTC3125应用:
GSM/GPRS PCMCIA/CompactFlash PC Card Modems
Wireless Emergency Locators
Portable Radios
Supercap Chargers



图1.LTC3125方框图



图2.LTC3125应用电路图(1)



图3.LTC3125应用电路图(2)



图4.LTC3125应用电路图(3)



图5.LTC3125应用电路图(4)



图6.LTC3125应用电路图(5)



图7.LTC3125应用电路图(6)



图8.LTC3125应用电路图(7)