Linear LTC3596 USB电源管理方案

Linear 公司的LTC3596是高度集成的电源管理和锂离子/聚合物电池充电器,具有升/降压稳压器(1A输出),升压稳压器(800mA输出)和两个降压稳压器(400mA输出),能提供1.5A的充电电流,并自动区分负载:对于USB应用能自动限流在100mA或500mA,而对于交流适配器,能限流在1A.无负载时的静态电流小于30uA,因此,可广泛用于数码相机,采用HDD的MP3播放器,PDA,GPS以及PMP,手提的音频/视频和其它基于USB的手提设备.本文介绍了LTC3596的主要特性,方框图以及典型的应用电路.

Linear LTC3586: Switch Mode USB Power Manager, Buck-Boost, Boost & Dual Buck Regulator PMIC Maximizes Battery Runtime in Compact 24mm2 Footprint
The LTC3586 is a highly integrated power management and battery charger IC for Li-Ion/Polymer battery applications. It includes a high efficiency current limited switching
PowerPath manager with automatic load prioritization, battery charger, ideal diode, and four synchronous switching regulators (two bucks, one buck-boost, and one boost).

Designed specifically for USB applications, the LTC3586’s switching power manager automatically limits input current to a maximum of either 100mA or 500mA for USB
applications or 1A for adapter-powered applications.
Unlike linear PowerPath controllers, the LTC3586’s switching input stage transmits nearly all of the 2.5W available from the USB port to the system load with minimal power wasted as heat. This feature allows the LTC3586 to provide more power to the application and eases the constraint of thermal budgeting in small spaces. The two buck regulators can provide up to 400mA each, the buck-boost can deliver 1A, and the boost delivers at least 800mA.
The LTC3586 is available in a low-profile (0.75mm) 38-pin 4mm 6mm QFN package.

主要特性:
Power Manager
High Efficiency Switching PowerPathTM Controller with Bat-TrackTM Adaptive Output Control and “Instant-On” Operation
Programmable USB or Wall Current Limit (100mA/500mA/1A)
Full Featured Li-Ion/Polymer Battery Charger
1.5A Maximum Charge Current
Internal 180mΩ Ideal Diode Plus External Ideal Diode Controller Powers Load in Battery Mode
<30μA No-Load Quiescent Current when Powered from BAT
DC/DCs
Dual High Efficiency Buck DC/DCs (400mA IOUT)
High Efficiency Buck-Boost DC/DC (1A IOUT)
High Efficiency Boost DC/DC (800mA IOUT)
All Regulators Operate Synchronously at 2.25MHz

应用:
Digital Still Cameras
HDD-Based MP3 Players, PDAs, GPS, PMPs
Portable Audio/Video
Other USB-Based Handheld Products



图1. LTC3586方框图



图2. LTC3586典型应用



图3.LTC3586用作微控制器看门狗电路