MAX17047/MAX17050
ModelGauge m3 Fuel Gauge
When a proper end-of-charge event is detected, the
device learns a new FullCAP register value based on
the RemCap output. If the old FullCAP value was too
high, it is adjusted downward after the last valid end-
of-charge detection. If the old FullCAP was too low, it is
The device detects end of charge if all the following con-
ditions are met:
REP
•ꢀ SOC > FullSOCThr
VF
•ꢀ ANDꢀICHGTermꢀxꢀ0.125ꢀ<ꢀCurrentꢀ<ꢀICHGTermꢀxꢀ1.25
•ꢀ ANDꢀ ICHGTermꢀ xꢀ 0.125ꢀ <ꢀ AverageCurrentꢀ <ꢀ
adjusted upward to match RemCap
the calculated state of charge from ever reporting a value
greater than 100%. See Figure 27.
. This prevents
REP
ICHGTerm x 1.25
Values are stored in FV. Multiply the termination current
by the sense resistor to determine the desired register
value. This register has the same range and resolution
as the Current register. Figure 28 shows the ICHGTerm
register format. ICHGTerm defaults to 150mA (03C0h) at
power-up.
ICHGTerm Register (1Eh)
The ICHGTerm register allows the device to detect when
a charge cycle of the cell has completed. The host
should set the ICHGTerm register value equal to the
exact charge termination current used in the application.
AVERAGE CURRENT
CURRENT
CHARGING
1.25 x ICHGTerm
0.125 x ICHGTerm
0mA
HIGH-CURRENT LOAD SPIKES DO NOT GENERATE END-OF-CHARGE
DETECTION BECAUSE CURRENT AND AVERAGE CURRENT READINGS
DO NOT FALL INTO THE DETECTION AREA AT THE SAME TIME.
DISCHARGING
AVERAGE CURRENT
CURRENT
CHARGING
1.25 x ICHGTerm
0.125 x ICHGTerm
0mA
DISCHARGING
EARLY CHARGER REMOVAL DOES NOT GENERATE END-OF-CHARGE
DETECTION BECAUSE CURRENT AND AVERAGE CURRENT READINGS
DO NOT FALL INTO THE DETECTION AREA AT THE SAME TIME.
Figure 27. FullCAP Learning at End of Charge
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