FEATURES

3- or 4-Cell Series Protection Control

Autonomous Overcurrent and Short Circuit

Protection

Provides Individual Cell Voltages to Battery

Management Host

Integrated Cell Balancing Control

I2C Compatible User Interface Allows Access

to Battery Information

User Control to Initiate Protection

Integrated 3.3-V 25-mA LDO

Programmable Shutdown and Brownout

Control

Provides Drive for Three External FETs

Low Supply Current of 140 μA Typical

Programmable Threshold and Delay for

Short-Circuit Current Protection

Provides Drive for Three External FETs

Can Directly Interface With bq2083/5 for

Complete Battery Management Solution

APPLICATIONS

Notebook Computer Battery Packs

Test Equipment

DESCRIPTION

The bq29311 is a three- or four-cell lithium-ion battery

pack protection analog front end (AFE) IC that

incorporates a 3.3-V 25-mA low-dropout regulator

(LDO) and an I2C compatible interface to extract battery

parameters such as cell voltages and control output

status. Other parameters, such as overcurrent

protection threshold and delay, can also be

programmed into the bq29311 to increase the flexibility

of the battery management system.

The bq29311 provides safety protection in overcurrent,

short circuit, overvoltage, and undervoltage conditions

via control from the battery management host. In

overcurrent and short-circuit conditions the bq29311

can directly activate the FET drive as a secondary

protection level. The communications interface allows

the host to control and observe the current status of the

protection, to set overcurrent and overload levels, to set

the overcurrent and overload blanking delay time,

short-circuit threshold levels, and short-circuit blanking

delay time, and to program for the VREG shutdown

voltage and brownout-detection thresholds.

Each cell is balanced by a discharge path, which is

enabled by the internal control registers accessible

through the I2C compatible interface. The maximum

current is set by an external series resistor with an

absolute maximum value of 10 mA discharge current

per cell.