BQ3060 Datasheet, PDF (14/17 Pages) Texas Instruments – SBS 1.1-COMPLIANT GAS GAUGE and PROTECTION with CEDV

bq3060
SLUS928A – MARCH 2009 – REVISED NOVEMBER 2009
www.ti.com
Voltage
The bq3060 updates the individual series cell voltages at one second intervals. The internal ADC of the bq3060
measures the voltage, scales, and offsets, and calibrates it appropriately. To ensure an accurate differential
voltage sensing, the IC ground should be connected directly to the most negative terminal of the battery stack,
not to the positive side of the sense resistor. This minimizes the voltage drop across the PCB trace.
Voltage Calibration and Accuracy
The bq3060 is calibrated for voltage prior to shipping from TI. The bq3060 voltage measurement signal chain
(ADC, high voltage translation, circuit interconnect) will be calibrated for each cell. The external filter resistors,
connected from each cell to the VCx input of the bq3060, are required to be 1kΩ. The accuracy of the
factory-calibrated devices is +/- 10mV per cell at room temperature at 4V cell voltage. Without any customer
voltage calibration, this is the level of accuracy expected as long as the filter resistor value is 1kΩ. If better
voltage accuracy is desired, customer voltage calibration is required. An application note on calibrating and
programming the bq3060 is available in the product web folder. See Data Flash Programming and Calibrating the
bq3060 Gas Gauge(SLUA502) for more details.
Current
The bq3060 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 bq3060 can automatically calibrate its offset between the A to D converter and the output of the high voltage
translation circuit. Also, the bq3060 provides an auto-calibration for the coulomb counter to cancel the voltage
offset error across SRN and SRP for maximum charge measurement accuracy. The bq3060 performs
auto-calibration when the SMBus lines stay low continuously for a minimum of 5 s.
Temperature
The bq3060 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 is Semitec 103AT) to sense the battery cell
temperature. The bq3060 can be configured to use internal or up to 2 external temperature sensors.
Communications
The bq3060 uses SMBus v1.1 with Master Mode and package error checking (PEC) options per the SBS
specification.
SMBus On and Off State
The bq3060 detects an SMBus off state when SMBC and SMBD are logic-low for ≥ 2 seconds. Clearing this
state requires either SMBC or SMBD to transition high. Within 1 ms, the communication bus is available.
SBS Commands
See bq3060 Technical Reference(SLUU319) for further details.
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REVISION HISTORY
Changes from Original (March 2009) to Revision A
Page
• Changed Device From: Product Preview To: Production ..................................................................................................... 1
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