External Pin Functions
32
SLUUBE8 – September 2018
Copyright © 2018, Texas Instruments Incorporated
Functional Description
1 = ALERT is active high.
ALERT_EN = When set to 1, the ALERT pin is active.
SCALED = Scaled capacity and/or current bit
The mA and mAh settings and reports will take on a value that is artificially scaled. This setting has
no actual effect within the gauge. It is the responsibility of the host to reinterpret the reported values.
Scaled current measurement is achieved by calibrating the current measurement to a value lower
than actual.
SLEEP = The fuel gauge can enter SLEEP, if operating conditions allow. True when set.
SLPWAKECHG = Accumulate estimated charge on wake from sleep when
Current()
>
Sleep Current
, but not enough
to trigger a wake event. Enabled when set.
JEITA = Enables JEITA Temperature functionality. See
Charging and Charge Termination
Low Byte
DefaultFA = Default to FULL ACCESS mode on power up (1 = yes)
LFOONLY = Use LFO only for ADC conversions (1 = yes).
LFOONLY is a lower power mode, but has a reduction in accuracy.
NIMH_CHG_EN = When set, the device performs primary charge termination using the NiXX algorithm. See
NI_DT = When set, the device performs primary charge termination using the
Δ
T/
Δ
t algorithm. See
NI_DV = When set, the device performs primary charge termination using the –
Δ
Vt algorithm. See
WAKE_EN, WK_TH1,
WK_TH0 =
These bits configure the current wake function. See the
bq34210-Q1 Automotive 1-Series Cell
System-Side CEDV Fuel Gauge for Rarely Discharged Batteries Data Sheet
) for
threshold values.
2.2
External Pin Functions
2.2.1 Wake-Up Comparator
The wake-up comparator indicates a change in cell current while the fuel gauge is in SLEEP mode. The
Operation Config A [WK_TH1:WK_TH0]
bits select the appropriate comparator threshold for the sense
resistor value used. The
Operation Config A [WAKE_EN]
bit selects one of two possible voltage
threshold ranges for the given sense resistor selection. An internal interrupt is generated when the
threshold is reached in either the charge or discharge direction. Setting the
[WK_TH1]
and
[WK_TH0]
bits
to 0 disables this feature.
2.2.2 Autocalibration
The fuel gauge provides an autocalibration feature that measures the voltage offset error across SRP and
SRN as operating conditions change. It subtracts the resulting offset error from the normal sense resistor
voltage, V
SR
, for maximum measurement accuracy.
Autocalibration of the coulomb counter begins on entry to SLEEP mode, except if
Temperature()
is
≤
5°C
or
Temperature()
≥
45°C.
The fuel gauge also performs a single offset when:
•
The condition of
AverageCurrent()
≤
100 mA
•
{voltage change since last offset calibration
≥
256 mV} or {temperature change since last offset
calibration is greater than 8°C for
≥
60 s}.
Capacity and current measurements continue at the last measured rate during the offset calibration when
these measurements cannot be performed. If the battery voltage drops more than 32 mV during the offset
calibration, the load current has likely increased; thus, the offset calibration is stopped. The
CONTROL_STATUS()[CCA]
bit is set during coulomb counter autocalibration.
