MAX17047/MAX17050
ModelGauge m3 Fuel Gauge
RelDt2—Long Relaxation. This bit is set to a 1 whenever
registers calculate their values for the AtRate register
theoretical current instead. The AtRate register holds a
two’s-complement 16-bit value. Do not write 8000h to
this register. Figure 36 shows the AtRate register format.
the ModelGauge m3 algorithm detects that the cell has
been relaxed for a period of 48 to 96 minutes or longer.
This bit is cleared to 0 whenever the cell is no longer in a
relaxed state. See Figure 32.
Power-Up and Power-On Reset
DNR—Data Not Ready. This bit is set to 1 at cell inser-
tion and remains set until the output registers have been
updated. Afterwards, the IC clears this bit indicating the
fuel gauge calculations are now up to date. This takes
between 445ms and 1.845s depending on whether the
IC was in a powered state prior to the cell-insertion event.
Any power-on reset (POR) of the device resets all
memory locations to their default POR value. This
removes any custom cell characterization and applica-
tion data, affects ALRT interrupt and shutdown mode set-
tings, and resets all learned adjustments made by the fuel
gauge. To maintain accuracy of the fuel gauge and reset
operation settings of the device, the host must reload
all application memory data and restore all learned fuel-
gauge information. Note that the device may take up to
445ms to completely reset operation after a POR event
occurs. See Figure 37. Saved data should not be restored
until after this period is over. The following procedure is
recommended:
EDet—Empty Detection. This bit is set to 1 when the IC
detects that the cell empty point has been reached. This
bit is reset to 0 when the cell voltage rises above the
recovery threshold. See the V_empty register for details.
X—Don’t Care. This bit is undefined and can be logic
0 or 1.
AtRate Register (04h)
The AtRate register allows host software to estimate
remaining capacity, SOC, and time to empty for a theo-
retical load current. Whenever the AtRate register is pro-
grammed to 0 or a positive value, the device uses A/D
1) Read Status register. If POR = 0, exit.
2) Wait 600ms for POR operation to fully complete.
3) Restore all application register values.
measurements for determining the SOC , RemCap
,
AV
AV
4) Restore fuel gauge learned-value information (see the
and TTE register values. Whenever the AtRate register is
programmed to a negative value indicating a hypotheti-
Save and Restore Registers section).
5) Clear POR bit.
cal discharge current, the SOC , RemCap , and TTE
AV
AV
MSB—ADDRESS 04h
LSB—ADDRESS 04h
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
S
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
MSb
LSb
MSb
0
LSb
2 UNITS: 1.5625FV/R
SENSE
X = DON’T CARE
Figure 36. AtRate Register Format (Input)
���������������������������������������������������������������� Maxim Integrated Products 27
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
