1 Features

• 2-Series Cell Secondary Protection
• Automatic Cell Imbalance Correction with External Enable Control
  • ±30-mV Enable, 0-mV Disable Thresholds Typical
• External Capacitor-Controlled Delay Timer
• External Resistor-Controlled Cell Balance Current
• Low Power Consumption I_CC < 3 µA Typical (V_CELL(ALL) < V_PROTECT)
• Internal Cell Balancing Handles Current
  up to 15 mA
• External Cell Balancing Mode Supported
• High-Accuracy Overvoltage Protection:
  • ±25 mV with T_A = 0°C to 60°C
• Fixed Overvoltage Protection Thresholds:
  4.30 V, 4.35 V
• Small 8L DRB Package

2 Applications

• 2^nd Level Protection in Li-Ion Battery Packs
  • Netbook Computers
  • Power Tools
  • Portable Equipment and Instrumentation
  • Battery Backup Systems

3 Description

The bq2920x device is a secondary overvoltage protection IC for 2-series cell lithium-ion battery packs that incorporates a high-accuracy precision overvoltage detection circuit and automatic cell imbalance correction.

The voltage of each cell in a 2-series cell battery pack is compared to a factory programmed internal reference voltage. If either cell reaches an overvoltage condition, the OUT pin changes from low to high state.

The bq2920x can perform automatic voltage-based cell imbalance correction. Balancing can start when the cell voltages are different by nominally 30 mV or more and stops when the difference is nominally 0 mV. Cell balancing is enabled and disabled by the CB_EN pin.

1. For all available packages, see the orderable addendum at the end of the datasheet.

Simplified Schematic