bq20z45-R1

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SLUS992 – DECEMBER 2009

Voltage

The bq20z45-R1 updates the individual series cell voltages at one second intervals. The internal ADC of the

bq20z45-R1 measures the voltage, scales and calibrates it appropriately. This data is also used to calculate the

impedance of the cell for the Impedance Track™ gas-gauging.

Current

The bq20z45-R1 uses the SRP and SRN inputs to measure and calculate the battery charge and discharge

current using a 5 m

Ω to 20 mΩ typ. sense resistor.

Auto Calibration

The bq20z45-R1 provides an auto-calibration feature to cancel the voltage offset error across SRN and SRP for

maximum charge measurement accuracy. The bq20z45-R1 performs auto-calibration when the SMBus lines stay

low continuously for a minimum of 5 s.

Temperature

The bq20z45-R1 has an internal temperature sensor and inputs for 2 external temperature sensor inputs TS1

and TS2 used in conjunction with two identical NTC thermistors (default are Semitec 103AT) to sense the battery

environmental temperature. The bq20z45-R1 can be configured to use internal or up to 2 external temperature

sensors.

Copyright © 2009, Texas Instruments Incorporated

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Not Recommended For New Designs