BQ2050H_15 Datasheet, PDF (14/30 Pages) Texas Instruments – Low-Cost Lithium Ion Power Gauge™ IC

Not Recommended For New Designs
bq2050H
The first end-of-discharge warning flag (EDV1)
warns the user that the battery is almost empty. The
first segment pin, SEG₁, is modulated at a 4Hz rate if
the display is enabled once EDV1 is asserted, which
should warn the user that loss of battery power is immi-
nent. The EDV1 flag is latched until a valid charge has
been detected. The EDV1 threshold is externally con-
trolled via the VTS register (see Voltage Threshold Reg-
ister).
The EDV1 values are:
FLGS1 Bits
7 65 4
3
2
1
0
-
--
-
-
- EDV1 -
Where EDV1 is:
0 Valid charge action detected, V_SB ≥ V_TS
1 V_SB < V_TS providing that the discharge rate
is < 2C
The final end-of-discharge warning flag (EDVF) flag
is used to warn that battery power is at a failure condi-
tion. All segment drivers are turned off. The EDVF flag
is latched until a valid charge has been detected. The
EDVF threshold is set 25mV below the EDV1 threshold.
The EDVF values are:
FLGS1 Bits
7 65
4
3
2
-
-
-
-
-
-
1
0
- EDVF
Where EDVF is:
0 Valid charge action detected, V_SB ≥ (V_TS - 25mV)
1 V_SB < (V_TS -25mV) providing the discharge
rate is < 2C
Temperature Register (TMP)
The TMP register (address=02h) contains the battery
temperature.
The bq2050H contains an internal temperature sensor.
The temperature is used to set charge and discharge ef-
ficiency factors as well as to adjust the self-discharge co-
efficient. The temperature register contents may be
translated as shown in Table 9.
TMP Temperature Bits
7
6
5
4
3 21 0
TMP3 TMP2 TMP1 TMP0 -
-
-
-
The bq2050H calculates the gas gauge bits, GG3-GG0 as a
function of CACT and LMD. The results of the calculation
give available capacity in ¹¹⁶ increments from 0 to ¹⁵¹⁶.
TMP Gas Gauge Bits
76
5
4
3
2
1
0
-
-
-
- GG3 GG2 GG1 GG0
Table 9. Temperature Register
TMP3
0
0
0
0
0
0
0
0
1
1
1
1
1
TMP2
0
0
0
0
1
1
1
1
0
0
0
0
1
TMP1
0
0
1
1
0
0
1
1
0
0
1
1
0
TMP0
0
1
0
1
0
1
0
1
0
1
0
1
0
Temperature
T < -30°C
-30°C < T < -20°C
-20°C < T < -10°C
-10°C < T < 0°C
0°C < T < 10°C
10°C < T < 20°C
20°C < T < 30°C
30°C < T < 40°C
40°C < T < 50°C
50°C < T < 60°C
60°C < T < 70°C
70°C < T < 80°C
T > 80°C
Nominal Available Capacity Registers
(NACH/NACL)
The NACH high-byte register (address=03h) and the
NACL low-byte register (address=17h) are the main gas
gauging registers for the bq2050H. The NAC registers are
incremented during charge actions and decremented dur-
ing discharge and self-discharge actions. NACH and
NACL are set to 0 during a bq2050H reset.
Writing to the NAC registers affects the available charge
counts and, therefore, affects the bq2050H gas gauge opera-
tion. Do not write the NAC registers to a value greater than
LMD.
Battery Identification Register (BATID)
The BATID register (address=04h) is available for use
by the system to determine the type of battery pack.
The BATID contents are retained as long as V_RBI is
greater than 2V. The contents of BATID have no effect
on the operation of the bq2050H. There is no default
setting for this register.
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