Datasheet

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:
■
No valid charge initiations (charges greater than
2 NAC updates) occurred during the period be-
tween NAC = LMD and EDV1.
■
The self-discharge count is less than 6% of NAC.
■
The temperature is
≥
0°C when the EDV1 level
is reached during discharge.
■
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.
8
bq2013H