Rainbow Electronics MAX17047 - Manual (Page 23)

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MAX17047
ModelGauge m3 Fuel Gauge
Cell Characterization
Information Registers
Proper cell characterization is required to achieve accu-
racy. The following registers (
Table 1 ) hold information
that must be generated through a cell-characterization
procedure. Maxim provides a cell-characterization ser-
vice. Contact the factory for details.
Algorithm Configuration Registers
The following registers allow operation of the ModelGauge
m3 algorithm to be adjusted for the application. It is recom-
mended that the default values for these registers be used.
FilterCFG Register (29h)
The FilterCFG register sets the averaging time period for
all A/D readings, for mixing OCV results and coulomb-
count results. It is recommended that these values are
not changed unless absolutely required by the applica-
tion.
Figure 29 shows the FilterCFG register format:
CURR3:CURR0—Sets the time constant for the
AverageCurrent register. The default POR value of 4h gives
a time constant of 11.25. The equation setting the period is:
AverageCurrent time constant = 175.8ms O 2 (2+CURR)
VOLT2:VOLT0—Sets the time constant for the
AverageV
CELL
register. The default POR value of 2h gives
a time constant of 45.0s. The equation setting the period is:
AverageV
CELL
time constant = 175.8ms O 2 (6+VOLT)
MIX3:MIX0—Sets the time constant for the mixing algo-
rithm. The default POR value of Dh gives a time constant
of 12.8 hours. The equation setting the period is:
Mixing Period = 175.8ms O 2 (5+MIX)
TEMP2:TEMP0—Sets the time constant for the
AverageTemperature register. The default POR value of
1h gives a time constant of 12min. The equation setting
the period is:
AvergeTemperature time constant = 175.8ms x 2 (8 + TEMP)
X—Reserved. Do not modify.
Figure 29. FilterCFG Register Format (Input)
Table 1. Cell Characterization Information
Registers
REGISTER ADDRESS
Characterization Table (48 words) 80h to AFh
FullCap 10h
DesignCap 18h
ICHGTerm 1Eh
FullCapNom 23h
RCOMP0 38h
lavg_empty 36h
TempCo 39h
QResidual 00 12h
QResidual 10 22h
QResidual 20 32h
QResidual 30 42h
MSB—ADDRESS 29h LSB—ADDRESS 29h
X X
TEMP
2
TEMP
1
TEMP
0
MIX3 MIX2 MIX1 MIX0 VOLT2 VOLT1 VOLT0
CURR
3
CURR
2
CURR
1
CURR
0
MSb LSb MSb LSb