bq20z40-R1

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SLUS993 – DECEMBER 2009

Lifetime Data Logging Features

The bq20z40-R1 offers lifetime data logging, where important measurements are stored for warranty and

analysis purposes. The data monitored include:

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Lifetime maximum temperature

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Lifetime minimum temperature

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Lifetime maximum battery cell voltage

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Lifetime minimum battery cell voltage

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Lifetime maximum battery pack voltage

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Lifetime minimum battery pack voltage

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Lifetime maximum charge current

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Lifetime maximum discharge current

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Lifetime maximum charge power

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Lifetime maximum discharge power

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Lifetime maximum average discharge current

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Lifetime maximum average discharge power

•

Lifetime average temperature

Authentication

The bq20z40-R1 supports authentication by the host using SHA-1.

Power Modes

The bq20z40-R1 supports 3 different power modes to reduce power consumption:

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In Normal Mode, the bq20z40-R1 performs measurements, calculations, protection decisions and data

updates in 1 second intervals. Between these intervals, the bq20z40-R1 is in a reduced power stage.

•

In Sleep Mode, the bq20z40-R1 performs measurements, calculations, protection decisions and data update

in adjustable time intervals. Between these intervals, the bq20z40-R1 is in a reduced power stage. The

bq20z40-R1 has a wake function that enables exit from Sleep mode, when current flow or failure is detected.

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In Shutdown Mode the bq20z40-R1 is completely disabled.

CONFIGURATION

Oscillator Function

The bq20z40-R1 fully integrates the system and processor oscillators and, therefore, requires no pins or

components for this feature.

System Present Operation

The bq20z40-R1 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-R1 enters normal operating mode. When the pack is

removed from the system and the PRES input is high, the bq20z40-R1 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-R1 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

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