TI bq24078高电压7A大电流电池充电解决方案

TI公司的bq2407x系列是高电压1.5A锂电池线性充电器，具有系统功率通路管理功能，工作在USB端口或AC适配器，支持充电电流高达1.5A，输入电压高达28V，最大输入电流可在100-mA和500-mA选择，主要用在智能手机，手持媒体播放器，低功耗手持设备，手持游戏机，可穿戴，家庭自动化和手持医疗设备。本文介绍了bq24078主要特性，功能框图，主控制充电器应用电路以及评估模块bq24078 EVM主要特性，电路图，材料清单和PCB设计图。

The bq2407x is a family of integrated Li-Ion batterylinear chargers with system power path managementfunctionality targeted at space-constrained portableapplications. The devices operate from either a USBport or an AC adapter and support charge currents up to 1.5 A. The input voltage range with inputovervoltage protection supports unregulated adapters. The USB input current limit accuracy andstart up sequence allow the bq2407x to meet USB-IFinrush current specifications. Additionally， the inputdynamic power management （VIN-DPM） preventssystem crashes because of incorrectly configuredUSB sources and maximizes the power availablefrom the adapter.

The bq2407x features dynamic power pathmanagement （DPPM） that powers the system whilesimultaneously and independently charging thebattery. The DPPM circuit reduces the charge currentwhen the input current limit causes the system outputto fall to the DPPM threshold; thus， supplying thesystem load at all times while monitoring the charge current separately. This feature reduces the numberof charge and discharge cycles on the battery， allowsfor proper charge termination and enables the systemto run with a defective or absent battery pack.

Additionally， the regulated system input enables instant system turn-on when plugged in even with a totallydischarged battery. The power-path management architecture also lets the battery supplement the systemcurrent requirements when the adapter cannot deliver the peak system currents， thus enabling the use of asmaller adapter.

The battery is charged in three phases： conditioning， constant current， and constant voltage. In all chargephases， an internal control loop monitors the IC junction temperature and reduces the charge current if theinternal temperature threshold is exceeded. The charger power stage and charge current sense functions arefully integrated. The charger function has high accuracy current and voltage regulation loops， charge statusdisplay， and charge termination. The input current limit and charge current are programmable using externalresistors.

bq24078主要特性：

1• Fully Compliant USB Charger

– Selectable 100-mA and 500-mA MaximumInput Current

– 100-mA Maximum Current Limit EnsuresCompliance to USB-IF Standard

– Input-Based Dynamic Power Management（VIN-DPM） for Protection Against Poor USB Sources

• 28-V Input Rating with Overvoltage Protection

• Integrated Dynamic Power Path Management（DPPM） Function Simultaneously and

Independently Powers the System and Chargesthe Battery

• Supports up to 1.5-A Charge Current with CurrentMonitoring Output （ISET）

• Programmable Input Current Limit up to 1.5 A forWall Adapters

• System Output Tracks Battery Voltage

• Battery Disconnect Function with SYSOFF Input

• Programmable Pre-Charge and Fast-ChargeSafety Timers

• Reverse Current， Short-Circuit， and ThermalProtection

• NTC Thermistor Input

• Proprietary Start-up Sequence Limits InrushCurrent

• Battery Charge Voltage， VBAT：

– bq24076 - 4.4 V （typ）

– bq24078 - 4.35 V （typ）

• Status Indication – Charging/Done， Power Good

bq24078应用：

• Smart Phones

• Portable Media Players

• Portable Navigation Devices

• Low-Power Handheld Devices

• Portable Gaming

• Headsets

• Wearables

• Home Automation

• Portable Medical

图1.bq24078功能框图

图2.bq24078/76应用电路：主控制充电器

评估模块bq24078 EVM

This user’s guide describes the bq24076 and bq24078 （hereafter， bq24076/8） evaluation module （EVM）。

The EVM provides a convenient method for evaluating the performance of a charge management andsystem power solution for portable applications using the bq24076/8 product families. A completelydesigned and tested module is presented. The charger is designed to deliver up to 1.5 A of continuouscurrent to the system or charger for one-cell Li-ion or Li-polymer applications （see the data sheet forcorrect device） using a DC power supply. The charger is programmed from the factory to deliver 0.9 A ofcharging current. This EVM was designed as a stand-alone evaluation module， but it also can beinterfaced with the system and host via the connectors and headers.

The bq24078 evaluation module （EVM） provides a convenient method for evaluating the performance of a charge management and system power solution for portable applications using the bq24076/8 product. The charger is designed to deliver up to 1.5 A of continuous current to the system or charger for one-cell Li-ion or Li-polymer applications using a dc power supply.

评估模块bq24078 EVM主要特性：

bq24078 is a 1.5A USB-friendly li-ion battery charger and power-path management IC

28V input rating with overvoltage protection

Input-based dynamic power management （VIN-DPN） for protection against poor USB sources

图3.评估模块bq24078 EVM-015外形图

图4.评估模块bq24076/8 EVM电路图

评估模块bq24076/8 EVM材料清单：

图5.评估模块bq24076/8 EVM PCB顶层装配图

图6.评估模块bq24076/8 EVM PCB顶层腐蚀层

图7.评估模块bq24076/8 EVM PCB底层腐蚀层

详情请见：

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