BQ2050H_15 Datasheet, PDF (3/30 Pages) Texas Instruments – Low-Cost Lithium Ion Power Gauge™ IC

Not Recommended For New Designs
bq2050H
Functional Description
General Operation
The bq2050H determines battery capacity by moni-
toring the amount of current input to or removed
from a rechargeable battery. The bq2050H meas-
ures discharge and charge currents, measures bat-
tery voltage, estimates self-discharge, monitors the
battery for low battery-voltage thresholds, and com-
pensates for temperature and discharge rate. Cur-
rent measurement is measured by monitoring the
voltage across a small-value series sense resistor be-
tween the negative battery terminal and ground.
Scaled available energy is estimated using the re-
maining average battery voltage during the dis-
charge cycle and the remaining nominal available
capacity. The scaled available energy measurement
is corrected for environmental and operating condi-
tions.
Figure 1 shows a typical battery pack application of the
bq2050H using the LED display capability as a charge-
state indicator. The bq2050H is configured to display
capacity in relative display mode. The relative display
mode uses the last measured discharge capacity of the
battery as the battery “full” reference. A push-button
display feature is available for momentarily enabling
the LED display.
The bq2050H monitors the charge and discharge cur-
rents as a voltage across a sense resistor. (See R_S in Fig-
ure 1.) A filter between the negative battery terminal
and the SR pin is required.
bq2050H
Power Gauge IC
REF
LCOM
SEG1/PROG1
SEG2/PROG2
SEG3/PROG3
SEG4/PROG4
SEG5/PROG5
CFC
PSTAT
VCC
SB
DISP
SR
VSS
RBI
HDQ
R1
C1
VCC
100K
0.1µF
Q1
ZVNL110A
RB1
C2
RB2
RS
See note 4
Notes:
1.
Indicates optional.
2. Programming resistors and ESD-protection diodes are not shown.
3. RC on SR is required.
4. A series diode is required on RBI if the bottom series cell is used as the backup source.
If the cell is used, the backup capacitor is not required, and the anode is connected to the
positive terminal of the cell.
Charger
Load
FG2050H1.eps
Figure 1. Battery Pack Application Diagram—LED Display
3