BQ2013H Datasheet, PDF (8/24 Pages) Texas Instruments – Gas Gauge IC for Power- Assist Applications

bq2013H
The initial full battery capacity is 35mVh (4667mAh) until
the bq2013H “learns” a new capacity with a qualified dis-
charge from full to EDV1.
3. Nominal Available Capacity (NAC):
NAC counts up during charge to a maximum value
of LMD and down during discharge and self dis-
charge to 0. NAC is reset to 0 on initialization and
on the first valid charge following discharge to
EDV1. To prevent overstatement of charge during
periods of overcharge, NAC stops incrementing
when NAC = LMD. When the DONE input is as-
serted high, indicating full charge completion, NAC
is set to LMD.
4. Discharge Count Register (DCR):
The DCR counts up during discharge independent
of NAC and could continue increasing after NAC
has decremented to 0. Prior to NAC = 0 (empty
battery), both discharge and self-discharge incre-
ment the DCR. After NAC = 0, only discharge in-
crements the DCR. The DCR resets to 0 when NAC
= LMD. The DCR does not roll over but stops
counting when it reaches FFFFh.
The DCR value becomes the new LMD value on the
first charge after a valid discharge to EDV1 if all of
the following conditions are met:
I No valid charge initiations (charges greater than
2 NAC updates) occurred during the period be-
tween NAC = LMD and EDV1.
I The self-discharge count is less than 6% of NAC.
I The temperature is ≥ 0°C when the EDV1 level
is reached during discharge.
I VDQ is set.
Charge Counting
Charge activity is detected based on a positive voltage
on the V_SR input. If charge activity is detected, the
bq2013H increments NAC at a rate proportional to V_SRO
(V_SR + V_OS) and, if enabled, activates an LED display
if V_SRO > 500µV. Charge actions increment the NAC af-
ter compensation for charge rate and temperature.
The bq2013H detects charge activity with V_SRO > 250µV.
A valid charge equates to a sustained charge activity
greater than 2 NAC updates. Once a valid charge is de-
tected, charge counting continues until V_SRO drops be-
low 250µV.
Discharge Counting
All discharge counts where V_SRO < -250µV cause the
NAC register to decrement and the DCR to increment. If
enabled, the display is activated when V_SRO < -2mV.
The display remains active for 10 seconds after V_SRO
rises above - 2mV.
Self-Discharge Estimation
The bq2013H decrements NAC and increments DCR for
self-discharge based on time and temperature. The self-
discharge count rate is programmed per Table 3. This is
the rate for a battery temperature between 20–30°C.
The NAC register cannot be decremented below 0.
Count Compensations
The bq2013H determines fast charge when the NAC up-
dates at a rate of ≥ 2 counts/s. Charge activity is com-
pensated for temperature and rate before updating
NAC. Self-discharge estimation is compensated for tem-
perature before updating NAC or DCR.
Charge Compensation
Charge efficiency factors are selected using Table 5 for
trickle charge and fast charge. Fast charge is defined as
a rate of charge resulting in ≥ 2 NAC counts/s (0.16C to
0.6C, depending on PFC selections; see Table 2).
Temperature adapts the charge rate compensation
factors over three ranges between nominal, warm, and
hot temperatures. Program pin 5 is used to select one of
three compensation programs. These values are shown
in Table 5.
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