BQ2085 Datasheet, PDF (13/56 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

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Table 4. Self-Discharge for Rate Programmed
TEMPERATURE
(°C)
Temp < 10
10 ≤ Temp <20
20 ≤ Temp <30
30 ≤ Temp <40
40 ≤ Temp <50
50 ≤ Temp <60
60 ≤ Temp <70
70≤ Temp
SELF-DISCHARGE RATE
1/4 Y% per day
1/2 Y% per day
Y% per day
2Y% per day
4Y% per day
8Y% per day
16Y% per day
32Y% per day
CAPACITY
vs
TIME
bq2085
SLUS541 – OCTOBER 2002
1000
800
TA = 15°C
600
TA = 25°C
400
200
0
0
TA = 35°C
TA = 45°C
10
20
30
40
50
60
70
Time – Days
Figure 4. Self-Discharge at 2.5%/Day at 25°C
Figure 4 illustrates how the self-discharge estimate algorithm adjusts RemainingCapacity( ) versus
temperature.
Battery Electronic Load Compensation
The bq2085 can be configured to compensate for a constant load (as from battery electronics) present in the
battery pack at all times. The bq2085 applies the compensation continuously when the charge or discharge is
below the digital filter. The bq2085 applies the compensation in addition to self-discharge. The compensation
occurs at a rate determined by the value stored in Electronics Load DF 0x2d. The compensation range is
0 µA–765 µA in steps of approximately 3 µA.
Midrange Capacity Corrections
The bq2085 applies midrange capacity corrections when the VCOR bit is set in Gauge Configuration DF 0x29.
The bq2085 adjusts RM to the associated percentage at three different voltage levels: VOC25, VOC50, and
VOC75. The VOC values represent the open circuit battery voltage at which RM corresponds to the associated
for each threshold.
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