1 Features

1• 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 ICC < 3 μA Typical

(VCELL(ALL) < VPROTECT)

• Internal Cell Balancing Handles Current

up to 15 mA

• External Cell Balancing Mode Supported

• High-Accuracy Overvoltage Protection:

– ±25 mV with TA = 0°C to 60°C

• Fixed Overvoltage Protection Thresholds:

4.30 V, 4.35 V

• Small 8L DRB Package

2 Applications

• 2nd 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.