BQ2050H_15 Datasheet, PDF (6/30 Pages) Texas Instruments – Low-Cost Lithium Ion Power Gauge™ IC

Not Recommended For New Designs
bq2050H
2. Programmed Full Count (PFC) or initial bat- Example: Selecting a PFC Value
tery capacity:
Given:
The initial LMD and gas gauge rate values are pro-
grammed by using PROG1–PROG4. The bq2050H
is configured for a given application by selecting a
PFC value from Table 2. The correct PFC may be
determined by multiplying the rated battery capac-
ity in mAh by the sense resistor value:
Battery capacity (mAh) _* sense resistor (Ω) =
PFC (mVh)
Sense resistor = 0.05Ω
Number of cells = 2
Capacity = 1000mAh, Li-Ion battery, coke-anode
Current range = 50mA to 1A
Relative display mode
Self-discharge
=
NAC
512
per
day
@
25°C
Voltage drop over sense resistor = 2.5mV to 50mV
Nominal discharge voltage = 3.6V
Therefore:
Selecting a PFC slightly less than the rated capac-
ity provides a conservative capacity reference until
the bq2050H “learns” a new capacity reference.
1000mAh _* 0.05Ω = 50mVh
Pin
Connection
H
Z
L
Table 1. Self-Discharge and Capacity Compensation
PROG₅ Compensation/Self-Discharge
(See Tables 3 and 4)
Coke anode/disabled
Coke
anode/
NAC
512
Graphite
anode/
NAC
512
DISP
Display State
LEDs disabled
LEDs on when charging
LEDs on for 4 s
Table 2. bq2050H Programmed Full Count mVh, V_SR Gain Selections
PROGx
12
Pro-
grammed
Full
Count
(PFC)
--
-
HH
49152
HZ
45056
HL
40960
ZH
36864
ZZ
33792
ZL
30720
LH
27648
LZ
25600
LL
22528
V_SR equivalent to 2
counts/s (nom.)
PROG₄ = L
PROG4 = Z or H
PROG₃ = H
SCALE =
1/80
614
563
512
461
422
384
346
320
282
PROG3 = Z PROG3 = L PROG3 = H PROG3 = Z PROG3 = L Units
SCALE = SCALE = SCALE = SCALE = SCALE = mVh/
1/160
1/320
1/640
1/1280
1/2560 count
307
154
76.8
38.4
19.2
mVh
282
141
70.4
35.2
17.6
mVh
256
128
64.0
32.0
16.0
mVh
230
115
57.6
28.8
14.4
mVh
211
106
53.0
26.4
13.2
mVh
192
96.0
48.0
24.0
12.0
mVh
173
86.4
43.2
21.6
10.8
mVh
160
80.0
40.0
20.0
10.0
mVh
141
70.4
35.2
17.6
8.8
mVh
90
45
22.5
11.25
5.6
2.8
mV
6