BQ34Z100 Datasheet, PDF (36/50 Pages) Texas Instruments – Wide Range Fuel Gauge with Impedance Track™ Technology

bq34z100
SLUSAU1 – MAY 2012
www.ti.com
NominalAvailableCapacity(): 0x14/0x15
This read-only command pair returns the uncompensated (no or light load) battery capacity remaining. Units are
1 mAh per bit.
FullAvailableCapacity(): 0x16/0x17
This read-only command pair returns the uncompensated (no or light load) capacity of the battery when fully
charged. Units are 1 mAh per bit. FullAvailableCapacity() is updated at regular intervals, as specified by the
Impedance Track algorithm.
TimeToEmpty(): 0x18/0x19
This read-only function returns an unsigned integer value of the predicted remaining battery life at the present
rate of discharge, in minutes. A value of 65535 indicates battery is not being discharged.
TimeToFull(): 0x1a/0x1b
This read-only function returns an unsigned integer value of predicted remaining time until the battery reaches
full charge, in minutes, based upon AverageCurrent(). The computation should account for the taper current time
extension from the linear TTF computation based on a fixed AverageCurrent() rate of charge accumulation. A
value of 65535 indicates the battery is not being charged.
StandbyCurrent(): 0x1c/0x1d
This read-only function returns a signed integer value of the measured standby current through the sense
resistor. The StandbyCurrent() is an adaptive measurement. Initially it reports the standby current programmed in
Initial Standby, and after spending some time in standby, reports the measured standby current.
The register value is updated every 1 second when the measured current is above the Deadband (3 mA default)
and is less than or equal to 2 x Initial Standby. The first and last values that meet this criterion should not be
averaged in, since they may not be stable values. To approximate a 1 minute time constant, each new
StandbyCurrent() value is computed as follows:
StandbyCurrent()_NEW = (239/256) × StandbyCurrent()_OLD + (17/256) × AverageCurrent()
StandbyTimeToEmpty(): 0x1e/0x1f
This read-only function returns an unsigned integer value of the predicted remaining battery life at the standby
rate of discharge, in minutes. The computation should use Nominal Available Capacity (NAC), the
uncompensated remaining capacity, for this computation. A value of 65535 indicates battery is not being
discharged.
MaxLoadCurrent(): 0x20/0x21
This read-only function returns a signed integer value, in units of mA, of the maximum load conditions. The
MaxLoadCurrent() is an adaptive measurement which is initially it reports the maximum load current programmed
in Initial Max Load Current. If the measured current is ever greater than Initial Max Load Current, then
MaxLoadCurrent() updates to the new current. MaxLoadCurrent() is reduced to the average of the previous value
and Initial Max Load Current whenever the battery is charged to full after a previous discharge to an SOC less
than 50%. This prevents the reported value from maintaining an unusually high value.
MaxLoadTimeToEmpty(): 0x22/0x23
This read-only function returns an unsigned integer value of the predicted remaining battery life at the maximum
load current discharge rate, in minutes. A value of 65535 indicates that the battery is not being discharged.
AvailableEnergy(): 0x24/0x25
This read-only function returns an unsigned integer value of the predicted charge or energy remaining in the
battery. The value is reported in units of mWh.
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