TI公司的bq25871是集成了10位ADC的14V 7A电池开关充电器,输入电压3-14V,集成了MOSFET和电流检测,集成的高精度ADC用来系统监测,高达1MHz I2C读和写速度,主要用在智能手机,平板电脑和有大电池容量的其它手持设备.本文介绍了bq25871主要特性,功能框图,应用电路以及充电器评估模块BQ25871EVM-813主要特性,电路图,材料清单和PCB设计图.
The device is a 7-A battery switch charger with an integrated 10-bit ADC. The high-current battery switch charger is a 13-mΩ MOSFET with reverse current blocking designed for high efficiency and minimal voltage drop. The high-charge current capability of the device makes it ideal for smartphones, tablets, and other portable devices with large battery capacity.

The integrated 10-bit ADC can measure input voltage and current, battery voltage and current, as well as battery temperature and input connector temperature. This allows the user application to continuously monitor the power input and battery charging parameters to ensure the safety of the battery charging. The flexible OVP and OCP thresholds for VBUS, VOUT, and battery can be modified via I²C registers as the battery goes through constant current (CC) and constant voltage (CV) mode.

The I²C serial interface of the device can operate at speeds up to 1 MHz and allows access to the ADC’s measurements of the different charging parameters and also allows for flexible software control of the device. The INT pin provides instantaneous feedback to the host in case of a fault condition. I²C status registers allow the host to read the current status of all faults and events.

bq25871主要特性:

Adapter Input Voltage Range: 3 V to 14 V
Allow up to 14-V Adaptor Voltage
Highly Integrated 7-A Battery Switch
Integrated MOSFETs and Current Sensing
Low R_DS(on) (13-mΩ) MOSFETs for High Current Operation
Integrated High Accuracy ADC for System Monitor
VBUS, VBAT, VOUT, VDROP Voltage
Input and Battery Current
Battery and VBUS Connector Temperature
Linear Regulation (LDO) Mode Operation
Four Linear Regulation Loops: IBUS, IBAT, VBAT and VOUT
Programmable Linear Regulation Thresholds
Programmable Safety Protections
VBUS, VOUT, and VBAT Over Voltage Protections (OVP)
IBUS and IBAT Over Current Protection (OCP)
IBUS Reverse Current Protection (RCP)
VDROP (VBUS-VOUT) OVP
VBUS Connector and Battery Thermal Protection
Thermal Shutdown
Interrupt Status Output For Host Processor Alert
Up To 1-MHz I²C Read and Write Speed
Low Battery Leakage Current in Battery Only Mode
WCSP Package for Small Footprint


图1.bq25871功能框图

图2.bq25871应用电路图

BQ25871充电器评估模块

This user’s guide provides detailed testing instructions for the bq25871 and bq25872 evaluation modules(EVM). Also included are descriptions of the necessary equipment, equipment setup, and procedures. Thereference documentation contains the printed-circuit board layouts, schematics, and the bill of materials(BOM).
The bq25871 evaluation module (EVM) is a complete charger module for evaluating the highly-integrated battery switch in WCSP package for 1 cell Li-Ion and Li-polymer battery in a wide range of smartphone and tablet applications.

BQ25871充电器评估模块BQ25871EVM-813主要特性:
Input voltage range of 3V to 14V and charge current up to 7A
Highly integrated 7A battery switch and high accuracy ADC
Programmable protection and safety features
Test points for all signals available for testing purposes
Jumpers for different circuit configuration

图3.BQ25871EVM-813充电器评估模块外形图

图4.BQ25871EVM-813充电器评估模块电路图
BQ25871EVM-813充电器评估模块材料清单:

图5.BQ25871EVM-813充电器评估模块PCB设计图(顶层)

图6.BQ25871EVM-813充电器评估模块PCB设计图(中间层1)

图7.BQ25871EVM-813充电器评估模块PCB设计图(中间层2)

图8.BQ25871EVM-813充电器评估模块PCB设计图(底层)

图9.BQ25871EVM-813充电器评估模块PCB设计图(顶层装配)

图10.BQ25871EVM-813充电器评估模块PCB设计图(底层装配)