BQ2016 Datasheet, PDF (11/21 Pages) Texas Instruments – GAS GAUGE IC FOR HIGH DISCHARGE RATES

bq2016
GAS GAUGE IC FOR
HIGH DISCHARGE RATES
SLUS475A– JANUARY 2001 – REVISED NOVEMBER 2002
programmable configuration settings (continued)
internal or external thermistor
The PROG pin programs whether the bq2016 uses an internal or external thermistor according to the following
table. It also defines the fast charge and trickle-rate detection thresholds for NAC calibration.
Table 3. PROG Selections
PROG LEVEL LOW NOM (VCC)
HI
T
1
0/12
≤ 1/12 <
2/12 I
2
2/12
≤ 3/12 <
4/12 I
3
4/12
≤ 5/12 <
6/12 I
4
6/12
≤ 7/12 <
8/12 E
5
8/12
≤ 9/12 <
10/12 E
TRICKLE RATE
VDMF < VSR < 2 mV
VDMF < CRate < C/8
—
VDMF < VSR < 2 mV
VDMF < CRate < C/8
FAST CHARGE
DETECTION THRESHOLD
(FCDT)
VSR > 2 mV for 30s
CRate > C/5 for 30s
—
> 2 mV for 30s
CRate > C/5 for 30s
Rv (k) Rg (k)
Open
1000
1000
715
332
0
332
715
1000
1000
6
10/12
≤ 11/12 ≤
12/12 E
—
—
0
Open
NOTE: The bq2016 does not perform NAC calibration on charge with options 3 and 6. VDMF = 300 µV uncalibrated or 100 µV calibrated.
programming example
Given:
Sense resistor = 0.003 Ω
Chemistry = NiCd
Capacity = 2000 mAh
Discharge current range = 1 A to 10 A
Charge current = 200 mA to 4 A
Voltage drop over sense resistor = –30 mV to 12 mV
Internal thermistor with 2 mV FCDT
Therefore
2000 mAh × 0.003 = 6 mVh
Select
VPFC level = 5
PROG level = 1
TS pin = grounded
The initial full battery capacity is 5.4 mVh (1800 mAh) until the bq2016 learns a new capacity with a qualified
discharge from full to EDV.
charge and discharge count counting
charge counting
The bq2016 detects charge activity when V_SR = V_SR2 – V_SR1 is greater than the digital filter threshold. If charge
activity is detected, the bq2016 increments NAC at a rate proportional to VSR and activates the LED display
if V_SR > 2 mV. Charge actions increment the NAC after compensation for charge rate and temperature. Charge
counting continues until V_SR drops below VDMF.
discharge counting
The bq2016 detects discharge activity when V_SR = V_SR2 – V_SR1 is more negative than the digital filter threshold.
If discharge activity is detected, the bq2016 decrements NAC and increments DCR at a rate proportional to
V_SR and activates the LED display if V_SR < –2 mV. Discharge actions decrement NAC and increment DCR after
compensation for discharge rate and temperature. Discharge counting continues until V_SR rises above –VDMF.
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