MAX17047/MAX17050
ModelGauge m3 Fuel Gauge
(5+MIX)
Mixing Period = 175.8ms O 2
Algorithm Configuration Registers
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:
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.
(8 + TEMP)
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 30 shows the FilterCFG register format:
AvergeTemperature time constant = 175.8ms x 2
X—Reserved. Do not modify.
RelaxCFG Register (2Ah)
The RelaxCFG register defines how the device detects
if the cell is in a relaxed state. See Figure 32. For a cell
to be considered relaxed, current flow through the cell
must be kept at a minimum while the change in the cell’s
voltage over time, dV/dt, shows little or no change. If
AverageCurrent remains below the Load threshold while
changes less than the dV threshold over two
consecutive periods of dt, the cell is considered relaxed.
Figure 31 shows the RelaxCFG 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 seconds. The equation setting the
period is:
V
CELL
(2+CURR)
AverageCurrent time constant = 175.8ms O 2
VOLT2:VOLT0—Sets the time constant for the
AverageV
register. The default POR value of 2h gives
CELL
Load6:Load0—Sets the threshold, which the
AverageCurrent register is compared against. The
AverageCurrent register must remain below this thresh-
old value for the cell to be considered unloaded. Load is
an unsigned 7-bit value where 1 LSb = 50FV. The default
value is 800FV.
a time constant of 45.0s. The equation setting the period is:
(6+VOLT)
time constant = 175.8ms O 2
AverageV
CELL
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:
MSB—ADDRESS 29h
LSB—ADDRESS 29h
TEMP TEMP TEMP
CURR CURR CURR CURR
MIX0 VOLT2 VOLT1 VOLT0
X
X
MIX3 MIX2 MIX1
LSb
2
1
0
3
2
1
0
MSb
MSb
LSb
Figure 30. FilterCFG Register Format (Input)
MSB—ADDRESS 2Ah
LSB—ADDRESS 2Ah
dV3 dV2 dV1 dV0 dt3 dt2 dt1 dt0
MSb LSb
6
5
4
3
2
1
0
Load Load Load Load Load Load Load
dV4
LSb
MSb
0
LOAD UNITS: 50FV/R
SENSE
(5.0mAh WHEN R
= 0.010I)
SENSE
Figure 31. RelaxCFG Register Format (Input)
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