Only For Training And Service Purposes - LG GT500 Service Manual

3. TECHNICAL DESCRIPTION
3.5.1 Fuel Gauge
AB3100 supports the measurement of the current consumption/charging current in the GT500 with a fuel
gauge block. By constantly integrating the current flowing into and out of the battery, the fuel gauge
block is used to determine the remaining battery capacity.
The function of the fuel gauge block is schematically described in (Fig.3-5-3). A sense resistor R_FGSENSE
is connected in series with the battery. The voltage across the resistor, equivalent to the current
entering/leaving the battery, is integrated using an ADC block.
2012
1/4W
1%
Name
FGS+
FGS-
LGE Internal Use Only
Fig. 3-5-2. The analog front-end of the fuel gauge block
R324
Route as a differential pair
0.025
Fig. 3-5-3 The Schematic of the fuel gauge block
Type Unused
Analog VBAT
Analog VBAT
Table 3-5-2. Fuel Gauge channel spec
FGS+
VBAT
FGS-
Description
Fuel gauge current sensing input positive
Fuel gauge current sensing input negative
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M2
SRST_n SRST_N
M1
SCLK SCLK
N3
SDAT SDAT
A11
BDATA BDATA
J14
FGS+ FGSENSEP
VA605
varistor
J13
FGS- FGSENSEN
G2
VBAT_D
H1
CHS+ CHSENSEP
H2
CHS- CHSENSEN
H3
CHREG CHREG

Only for training and service purposes