BQ20Z80-V102 Datasheet, PDF (8/24 Pages) Texas Instruments – SBS 1.1-COMPLIANT GAS GAUGE ENABLED WITH IMPEDANCE TRACK-TM TECHNOLOGY FOR USE WITH THE bq29312A

bq20z80-V102
SLUS681A – NOVEMBER 2005 – REVISED MARCH 2006
FEATURE SET
www.ti.com
Primary (1st Level) Safety Features
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
Secondary (2nd Level) Safety Features
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
Charge Control Features
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.
• Determinea 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
• report charging faults and also indicate charge status via charge and discharge alarms.
Gas Gauging
The bq20z80 uses the Impedance Track™ Technology to measure and calculate the available charge in battery
cells. The archievable accuracy is better than 1% error over the lifetime of the battery and there is no full charge
discharge learning cycle required.
See Theory and Implementation of Impedance Track Battery Fuel-Gauging Algorithm application note (SLUA364)
for further details.
8
Submit Documentation Feedback