BQ29312A Two, Three and Four Cell Lithium or Lithium-Polymer Battery Protection AFE |

BQ29312A (NRND) Two, Three and Four Cell Lithium or Lithium-Polymer Battery Protection AFE


Not Recommended for New Designs (NRND)

Replaced By BQ76920 – The device has SIMILAR FUNCTIONALITY but is not functionally equivalent to the compared device.

TI does not recommend using this part in a new design. This product continues to be in production to support existing customers.


The bq29312A is a 2-, 3-, or 4-cell lithium-ion battery pack protection analog front end (AFE) IC that incorporates a 3.3-V, 25-mA low-dropout regulator (LDO). The bq29312A also integrates an I2C compat- ible interface to extract battery parameters such as cell voltages and control output status. Other par- ameters such as current protection thresholds and delays can be programmed into the bq29312A to increase the flexibility of the battery management system.

The bq29312A provides safety protection for over- charge, overload, short-circuit, overvoltage, and undervoltage conditions with the battery management host. In overload and short-circuit conditions, the bq29312A turns the FET drive off autonomously dependant on the internal configuration setting.

The communications interface allows the host to observe and control the current status of the bq29312A. It enables cell balancing, enters different power modes, sets overload levels, sets the overload blanking delay time, sets short-circuit threshold levels for charge and discharge, and sets the short-circuit blanking delay time.

Cell balancing of each cell is performed via a cell bypass path, which is enabled via the internal control register accessible via the I2C compatible interface. The maximum bypass current is set via an external series resistor and internal FET on resistance (typical 400 ).


  • 2-, 3-, or 4-Cell Series Protection Control
  • Can Directly Interface With the bq2084 Gas Gauges
  • Provides Individual Cell Voltages and Battery Voltage to Battery Management Host
  • Integrated Cell Balancing Drive
  • I2C Compatible User Interface Allows Access to Battery Information
  • Programmable Threshold and Delay for Overload and Short Circuit During Charge and Discharge
  • System Alert Interrupt Output
  • Host Control Can Initiate Sleep Power Mode and Ship Mode
  • Integrated 3.3-V, 25-mA LDO
  • Supply Voltage Range From 4.5 V to 25 V
  • Low Supply Current of 60-µA Typical
  • bq29312A is 100% specification compatible with the bq29312
    • Notebook PCs
    • Medical and Test Equipment
    • Portable Instrumentation