ADI公司的ADP5065是一款内嵌互联直流电压充电输出端与电池端的FET器件，通过FET可以实现电池隔离，当系统驱动电能来自于废电池或没有电池时，系统会立即切换到USB供电模式。ADP5065的输入电压范围为4V至5.5V，最大输入电压高达20V。ADP5065充电器兼容USB2.0、USB3.0和USB电池充电规范1.1。本文通过总结ADP5065器件的特点，分别介绍器件、特性、应用方向及内部结构框图，并给参考设计实例原理图、制板图及元器件清单。
The ADP5065 charger is fully compliant with the USB 2.0, USB 3.0, and USB Battery Charging Specification 1.1 and enables charging via the mini USB VBUS pin from a wall charger, car charger, or USB host port.
The ADP5065 operates from a 4 V to 5.5 V input voltage range but is tolerant of voltages of up to 20 V. This alleviates the concerns about the USB bus spiking during disconnect or connect scenarios.
The ADP5065 also features an internal FET between the dc-to-dc charger output and the battery. This permits battery isolation and, hence, system powering under a dead battery or no battery scenario, which allows for immediate system function on connection to a USB power supply.
Based on the type of USB source, which is detected by an external USB detection chip, the ADP5065 can be set to apply the correct current limit for optimal charging and USB compliance.
The ADP5065 comes in a very small and low profile 20-lead WLCSP (0.5 mm pitch spacing) package.

ADP5065主要特性：
3 MHz switch mode charger
1.25 A charge current from dedicated charger
Up to 680 mA charging current from 500 mA USB host
Operating input voltage from 4.0 V up to 5.5 V
Tolerant input voltage −0.5 V to +20 V (USB VBUS)
Dead battery isolation FET between battery and charger output
Battery thermistor input with automatic charger shutdown for when battery temperature exceeds limits
Compliant with the JEITA Li-Ion battery charging temperature specification
SYS_EN_OK flag to hold off system turn-on until battery is at minimum required level for guaranteed
syste_ startup due to minimum battery voltage and/or minimum battery charge level requirements
EOC programming with C/20, C/10 and specific current level selection

ADP5065应用：
Digital still cameras
Digital video cameras
Single cell Li-Ion portable equipment
PDA, audio, GPS devices
Mobile phones

图1. ADP5065方框图

ADP5065设计原理图：

图2. ADP5065设计原理图

ADP5065设计方案材料清单：


PCB元件布局图：