基于API9221设计的多种输入锂电池充电技术

基于API9221设计的多种输入锂电池充电技术

公司的API9221是可采用汽车/墙

或

电源的多种输入锂电池充电器,器件包括OVP USB旁路和4.9V/10mA

.USB过压保护5.4V, 墙适配器过压保护6.9V,安全电源输入高达28V,最大快速充电

1.2A,单独的

可编程充电电流和充电终止,反向电流保护和热保护.主要用在手持消费类

,手机,PDA,MP3播放器,手持

设备,数码相机和多媒体播放器.本文介绍API9221主要特性, 功能方框图和应用

图.

API9221: Car/Wall or USB Supply Input Lithium Bat

ry Charger with OVP USB Bypass and 10mA LDO

The API9221 has two supply inputs for highly integrated portable applica

ons, enabling charging from a USB host, wall

apter, or car adapter.

The PPR

n indicates to a host controller that a safe and valid supply is connected to either VUSB or VDC. The higher charge current op

on from VDC will take priority

both supplies are connected. The host controller

control the state of charging

the enable pin EN. The API9221 implements the constant current/constant voltage (CC/CV) charge algorithm for Lithium based battery cells. The connected cell will be charged to 4.2V with an accuracy of 1% over the en

re temperature range. The ter

na

on current is prog

mable via an external resistor, RIMIN.

The CHG pin indicates when the termination current is reached, and is reset by EN, power off, or battery below 3.9V. The maximum charge current can be programmed independently via the resistors RIUSB and RIVDC.

The API9221 comes with several protection features. To prevent system damage, the VUSB pin uses over voltage protection (OVP) at 5.4V, and the VDC OVP is at 6.9V. Above these levels, the non-operating device is protected ag

nst damage up to 28V. For control and system start-up the API9221 has a current limited

regulator.

To protect the chip against excessive power dissipation, temperature monitoring is integrated, which folds back the current to a safe level. As the temperature rises, this fold-back begins at 125°C without completely interrupting charging.

API9221主要特性:

• Linear Lithium Ion / Lithium Polymer charging IC

• Supplied from USB host or car/wall adapter

• Overvoltage protection USB: 5.4V, wall: 6.9V

• Supply inputs safe up to 28V

• Fast charging with maximum current of 1.2A

• Integrated linear regulator of 4.9V at 10mA with current limit

• Separate resistor-programmable charging current for wall and USB

• Resistor programmable end-of-charge

• Current limit on USB bypass path

• Indicator pins for charging and power present

• Enable pin to enable host control charging

• Reverse current protection

• Thermal protection

• DFN4030-12: Available in “Green” Molding Compound (No Br, Sb)

• Lead Free Finish/ RoHS Compliant

API9221应用:

• Handheld Consumer Devices

• Cell Phones, PDAs, MP3 Playe

• Handheld Test Equipment

• Digital Still Cameras

• Multimedia players

图1.API9221功能方框图

图2.API9221应用电路图

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