TI公司的bq77910是4-10个锂电池组的精密保护和平衡解决方案,采用内部的FET可对单个电池进行监视和平衡,直接驱动NMOS功率FET,和1毫欧姆或5欧姆检测电阻兼容,低静态电流,主要应用在无绳电动工具,无绳割草机,电动自行车,UPS,医疗设备和小型电动汽车(LEV).本文介绍了bq77910主要特性和优势,方框图,多种应用配置图以及bq77910EVM-001评估模块主要特性,电路图和材料清单.
The bq77910 precision protector is an integrated battery-protection and cell-balancing solution for Li-Ion battery packs. A single device can be configured to manage 4 to 10 cell battery packs. Two devices can be stacked to provide a solution for packs up to 20 cells in series.
This protection IC monitors individual cell voltages and can directly drive N-channel power MOSFETs to interrupt current flow during fault conditions. Fault detection and recovery criteria are fully programmable in non-volatile memory to suit all types of Li-Ion systems.Automatic cell balancing is provided using internal FETs. A robust balancing algorithm ensures optimum performance over the entire operating life of the pack.

bq77910主要特性:
4 ~ 10 series cell protection capability
Individual cell monitoring and balancing with internal FETs
NMOS power FET direct drive capability with flexible FET configuration
Compatible with 1 or 5 milliohm sense resistor
Low Quiescent Current (50 µA ON, 2.5 µA shutdown mode)
Programmable fault detection thresholds and time delays

bq77910优势:
Adaptable to a wide range of applications including power tools, E-Bikes, and UPS equipment
Maximizes battery pack service life and performance; minimizes external components required
Reduces total system cost and allows scaling of FETs as required for variable charging and discharge rates (application-specific)
Allows system designer to optimize for minimal loss or maximum sense accuracy as required by each application
Minimizes battery discharge during storage or idle periods
Adaptable to all variations of Li-Ion systems (LiCoO2, LiFePO4, and others)

bq77910应用:
• Cordless Power Tools
• Cordless Lawn Equipment
• Electric Bikes
• UPS
• Medical Equipment
• Light Electric Vehicles (LEV)

图1.bq77910功能方框图

图2.bq77910 5个电池串联FET配置图

图3.bq77910 采用CHGST引脚的串联FET配置图

图4.bq77910采用CHGST引脚并联(分离)电源通路FET配置图

图5.bq77910采用CHGST引脚不带充电FET的分离电源通路配置图

图6.bq77910单电源通路无FET配置图

图7.bq77910 VCELLx引脚不用时的配置图

bq77910EVM-001评估模块
The bq77910EVM-001 evaluation module (EVM) is a complete evaluation system for the bq77910, a four=to ten-cell Li-ion battery protection integrated circuit. The EVM consists of a bq77910 circuit module and a resistor cell simulator module which can be used for simple evaluation of the bq77910 functions. The circuit module includes one bq77910 integrated circuit (IC), sense resistor, power FETs and all other onboard components necessary to protect the cells from overcharge, over discharge, short circuit, and over current discharge in a 10 series cell Li-ion or Li-polymer battery pack. The circuit module connects directly across the cells in a battery. With a compatible interface board and Windows™-based PC software, the user can view the bq77910 registers and program the IC configuration and protection limits
If a designer wants to communicate with this EVM from a Windows-based PC, a separate USB Interface Adapter EVM is recommended. The USB-TO-GPIO Adapter serves as an interface adapter or a bridge between a host PC (IBM compatible) and one or multiple slave devices via a standard type-A to mini-B USB cable. The USB-TO-GPIO Adapter is listed below in the related tools section

bq77910EVM-001评估模块主要特性:
Complete evaluation system for the bq77910 four to ten series cell lithium-ion or lithium-polymer battery protector
Populated circuit module for 10 cell parallel FET configuration for quick setup - Pads for components for configuration of additional cell counts and series FETs
Power connections available on terminal blocks or banana jacks
Control and status signals available on terminal blocks
Resistor cell simulator for quick setup with only a power supply
PC software available for configuration

图8.bq77910EVM-001评估模块外形图

图9.bq77910EVM-001评估模块基本连接图

图10.bq77910EVM-001评估模块电路图(1)

图11.bq77910EVM-001评估模块电路图(2)

图12.电阻模拟器电路图

图13.bq77910EVM-001评估模块元件布局图
电阻模拟器材料清单:

bq77910EVM-001评估模块材料清单(BOM):