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 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 threshold:

4.30 V

• Small 8L DRB package

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

• Automotive-qualified AEC Q100 grade two

2 Applications

• 2nd level protection in li-ion battery packs

– Emergency call (eCall)

– Netbook computers

– Power tools

– Portable equipment and instrumentation

– Battery backup systems

3 Description

The BQ29209-Q1 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 BQ29209-Q1 can perform automatic voltagebased

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.