BQ20Z90_07 Datasheet, PDF (9/27 Pages) Texas Instruments – SBS 1.1-COMPLIANT GAS GAUGE ENABLED WITH IMPEDANCE TRACK™ TECHNOLOGY FOR USE WITH THE bq29330

bq20z90
www.ti.com
SLUS662A – DECEMBER 2005 – REVISED JUNE 2006
FEATURE SET (continued)
See Theory and Implementation of Impedance Track Battery Fuel-Gauging Algorithm application note
(SLUA364) for further details.
LED Display
The bq20z90 can drive a 3-, 4-, or 5- segment LED display for remaining capacity indication. The LED drive
current can be adjusted to 3mA, 4mA and 5mA digitally.
LifeTime Data Logging Features
The bq20z90 offers a lifetime data logging array, where all important measurements are stored for warranty and
analysis purposes. The data monitored include:
• Lifetime maximum temperature
• Lifetime minimum temperature
• Lifetime maximum battery cell voltage
• Lifetime minimum battery cell voltage
• Lifetime maximum battery pack voltage
• Lifetime minimum battery pack voltage
• Lifetime maximum charge current
• Lifetime maximum discharge current
• Lifetime maximum charge power
• Lifetime maximum discharge power
• Lifetime maximum average discharge current
• Lifetime maximum average discharge power
• Lifetime average temperature
Authentication
The bq20z90 supports authentication by the host using SHA-1.
Power Modes
The bq20z90 supports 3 different power modes to reduce power consumption:
• In Normal Mode, the bq20z90 performs measurements, calculations, protection decisions, and data updates
in 1 second intervals. Between these intervals, the bq20z90 is in a reduced power stage.
• In Sleep Mode, the bq20z90 performs measurements, calculations, protection decisions, and data updates
in adjustable time intervals. Between these intervals, the bq20z90 is in a reduced power stage.
• In Shutdown Mode the bq20z90 is completety disabled.
CONFIGURATION
Oscillator Function
The bq20z90 fully integrates the system and processor oscillators and, therefore, requires no pins or
components for this feature.
System Present Operation
The bq20z90 periodically verifies the PRES pin and detects that the battery is present in the system via a low
state on a PRES input. When this occurs, bq20z90 enters normal operating mode. When the pack is removed
from the system and the PRES input is high, the bq20z90 enters the battery-removed state, disabling the
charge, discharge and ZVCHG FETs. The PRES input is ignored and can be left floating when non-removal
mode is set in the data flash.
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