Linear LTC4099 USB/锂离子电池充电方案

Linear 公司的LTC4099是通过I2C控制的 USB PowerPath 控制器和全特性的锂离子/聚合物电池充电器,能无缝地管理多种电源包括USB,墙上适配器和锂离子/聚合物电池. LTC4099能自动设限,以便和USB兼容.对于汽车电子和其它高压应用, LTC4099能和外接开关稳压器接口. LTC4099最大充电电流为1.5A,可用于媒体播放器,手提导航设备,智能手机,工业手提设备以及手提医疗设备.本文介绍了LTC4099的主要特性,方框图,USB PowerPath 方框图,以及多种应用电路图.

The LTC4099 is an I2C controlled high efficiency USB PowerPath™ controller and full-featured Li-Ion/Polymer battery charger. It seamlessly manages power distribution
from multiple sources including USB, a wall adapter and a Li-Ion/Polymer battery.

The LTC4099 automatically limits its input current for USB compatibility. For automotive and other high voltage applications, the LTC4099 interfaces with an external switching regulator. Both the USB input and the auxiliary input controller feature Bat-Track optimized charging to provide maximum power to the application and reduced
heat in high power density applications.

The I2C port allows digital control of important application parameters including input current limit, charge current and fl oat voltage. Several status bits can also be read back
via I2C. An overvoltage protection circuit guards the LTC4099 from high voltage damage on the low voltage VBUS pin. The LTC4099 is available in the ultra-thin (0.55mm) 20-lead
3mmx4mm QFN surface mount package.

LTC4099主要特性:
Switching Regulator with Bat-TrackTM Adaptive Output
Control Makes Optimal Use of Limited Input Power
I2C Port for Optimal System Performance and Status Information
Input Overvoltage Protection
Bat-Track Control of External Step-Down Switching Regulator Maximizes
Efficiency from Automotive and Other High Voltage Sources
Instant-On Operation with Low Battery
Optional Overtemperature Battery Conditioner Improves High Temperature Battery Safety Margin
Ideal Diode Seamlessly Connects Battery When Input Power is Limited or Unavailable
Full-Featured Li-Ion/Polymer Battery Charger
1.5A Maximum Charge Current with Thermal Limiting
Slew Control Reduces Switching EMI
Ultra-Thin (0.55mm) 20-Lead 3mmx4mm QFN

应用:
Media Players
Portable Navigation Devices
Smart Phones
Industrial Handhelds
Portable Medical Instruments



图1.LTC4099方框图



图2.PowerPath 方框图



图3.LTC4099 USB/汽车电池充电器电路图(带过压保护,反向电压保护和低电池电压起动)



图4.LTC4099 USB/墙上适配器电池充电器(带双过压保护,反向电压保护和低电池电压起动)



图5.LTC4099 USB/汽车开关的电池充电器,汽车输入2A



图6.LTC4099带高低电压输入的低元件数的电源管理电路