BQ20Z40 Datasheet, PDF (9/18 Pages) Texas Instruments – SBS 1.1-COMPLIANT GAS GAUGE ENABLED WITH IMPEDANCE TRACK™ TECHNOLOGY FOR USE WITH THE bq29330

bq20z40
www.ti.com................................................................................................................................................ SLUS801A – FEBRUARY 2009 – REVISED MARCH 2009
Lifetime Data Logging Features
The bq20z40 offers lifetime data logging, where 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 bq20z40 supports authentication by the host using SHA-1.
Power Modes
The bq20z40 supports 3 different power modes to reduce power consumption:
• In Normal Mode, the bq20z40 performs measurements, calculations, protection decisions and data updates in
1 second intervals. Between these intervals, the bq20z40 is in a reduced power stage.
• In Sleep Mode, the bq20z40 performs measurements, calculations, protection decisions and data update in
adjustable time intervals. Between these intervals, the bq20z40 is in a reduced power stage. The bq20z40
has a wake function that enables exit from Sleep mode, when current flow or failure is detected.
• In Shutdown Mode the bq20z40 is completely disabled.
CONFIGURATION
Oscillator Function
The bq20z40 fully integrates the system and processor oscillators and, therefore, requires no pins or
components for this feature.
System Present Operation
The bq20z40 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, bq20z40 enters normal operating mode. When the pack is removed
from the system and the PRES input is high, the bq20z40 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.
BATTERY PARAMETER MEASUREMENTS
The bq20z40 uses an integrating delta-sigma analog-to-digital converter (ADC) for current measurement, and a
second delta-sigma ADC for individual cell and battery voltage, and temperature measurement.
Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s) :bq20z40
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