www.ti.com

FEATURE SET

Primary (1st Level) Safety Features

Secondary (2nd Level) Safety Features

Charge Control Features

bq20z80-V102

SLUS681B – NOVEMBER 2005 – REVISED JANUARY 2007

NOTE:

The bq20z80-V102 is designed to work with the bq29312A AFE. The bq20z80

features are only available with the bq29312A.

.

The bq20z80 supports a wide range of battery and system protection features that can easily be configured. The

primary safety features includes:

• Battery cell over/under voltage protection

• Battery pack over/under voltage protection

• 2 independent charge overcurrent protection

• 3 independent discharge overcurrent protection

• Short circuit protection

• Over temperature protection

• Host watchdog

The secondary safety features of the bq20z80 can be used to indicate more serious faults via the SAFE (pin 7)

and SAFE (pin 12) pins. These pins can be used to blow a in-line fuse to permanently disable the battery pack

from charging or discharging. The secondary safety features includes:

• Safety over voltage

• Battery cell imbalance

• 2nd level protection IC input

• Safety over current

• Safety over temperature

• Open thermistor

• Charge FET and 0 Volt Charge FET fault

• Discharge FET fault

• Fuse blow failure detection

• AFE communication error

• Internal flash data error

The bq20z80 charge control features includes:

• Report the appropriate charging current needed for constant current charging and the appropriate charging

voltage needed for constant voltage charging to a smart charger using SMBus broadcasts.

• Determines the chemical state of charge of each battery cell using Impendance Track™ and can reduce the

charge difference of the battery cells in fully charged state of the battery pack gradually using cell balancing

algorithm during charging. This prevents fully charged cells from overcharging causing excessive degredation

and also increases the usable pack energy by preventing to early charge termination

• supports pre-charging/zero-volt charging

• support fast charging

• supports pulse charging

• detects charge termination

• report charging faults and also indicate charge status via charge and discharge alarms.

8

Submit Documentation Feedback