BQ2084DBTR-V150 Datasheet, PDF (9/69 Pages) Texas Instruments – SBS v1.1-COMPLIANT GAS GAUGE WITH LED DELAY

bq2084-V150
www.ti.com
SLUS758 – JUNE 2007
VOLTAGE
While monitoring SR1 and SR2 for charge and discharge currents, the bq2084-V150 monitors the individual
series cell voltages through the bq29312A. The bq2084-V150 configures the bq29312A to present the selected
cell to the CELL pin of the bq29312A, which should be connected to VIN of the bq2084-V150. The internal ADC
of the bq2084-V150 then measures the voltage and scales it appropriately. The bq2084-V150 then reports the
Voltage() and the individual cell voltages in VCELL1(), VCELL2(), VCELL3(), and VCELL4(). An additional
SMBus command (0x45) returns the measured ADC Reading of the PACK input to the AFE.
CURRENT
The bq2084-V150 uses the SR1 and SR2 inputs to measure and calculate the battery charge and discharge
current. This value is reported via the SBS command Current(). AverageCurrent() is implemented as a
single-pole IIR filter with a 14.5-s time constant.
TEMPERATURE
The TS input of the bq2084-V150 along with an NTC thermistor measures the battery temperature as shown in
the schematic. The bq2084-V150 reports temperature via the SBS command Temperature().
The bq2084-V150 can also be configured to use its internal temperature sensor by setting the IT bit in Misc
Configuration DF 0x2a-0x2b. Data flash locations DF 0xb5 through DF 0xc0 also have to be changed to
prescribed values if the internal temperature sensor option is selected.
LABEL
Misc. Config
TS Const1 A3
TS Const2 A2
TS Const3 A1
TS Const4 A0
Min Temp AD
Max Temp
Table 1. Data Flash Settings for Internal or External Temperature Sensor
LOCATION
Dec (Hex)
42 (0x2a)
164/5 (0xb5/6)
166/7 (0xb7/8)
168/9 (0xb9/a)
170/1 (0xbb/c)
172/3 (0xbd/e)
174/5 (0xbf/c0)
INTERNAL TEMP
SENSOR SETTING
Dec (Hex)
Bit 7 = 1
0 (0x0000)
0 (0x0000)
–11136 (0xd480)
5734 (0x1666)
0 (0x0000)
5734 (0x1666)
EXTERNAL TEMP SENSOR SETTING
(Semitec 103AT)
Dec (Hex)
Bit 7 = 0
–28285 (0x9183)
20848 (0x5170)
–7537 (0xe28f)
4012 (0x0fac)
0 (0x000)
4012 (0x0fac)
GAS GAUGE OPERATION
General
The operational overview in Figure 1 illustrates the gas gauge operation of the bq2084-V150. Table 3 describes
the bq2084-V150 registers.
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