bq20z45
www.ti.com .................................................................................................................................................................................................. SLUS800–MARCH 2009
Voltage
The bq20z45 updates the individual series cell voltages at one second intervals. The internal ADC of the
bq20z45 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 uses the SRP and SRN inputs to measure and calculate the battery charge and discharge current
using a 5 mΩ to 20 mΩ typ. sense resistor.
Auto Calibration
The bq20z45 provides an auto-calibration feature to cancel the voltage offset error across SRN and SRP for
maximum charge measurement accuracy. The bq20z45 performs auto-calibration when the SMBus lines stay
low continuously for a minimum of 5 s.
Temperature
The bq20z45 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 can be configured to use internal or up to 2 external temperature
sensors.
Copyright © 2009, Texas Instruments Incorporated
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