BQ2050H_15 Datasheet, PDF (1/30 Pages) Texas Instruments – Low-Cost Lithium Ion Power Gauge™ IC

Not Recommended For New Designs
bq2050H
Low-Cost Lithium Ion Power Gauge™ IC
Features
➤ Accurate measurement of avail-
able capacity in Lithium Ion bat-
teries
➤ Provides a low-cost battery man-
agement solution for pack
integration
- Complete circuit can fit in as
little
as
1
2
square
inch
of
PCB
- Low operating current (120µA
typical)
- Less than 100nA of data
retention current
➤ High-speed (5kb) single-wire
communication interface (HDQ
bus) for critical battery
parameters
➤ Monitors and controls charge FET
in Li-Ion pack protection circuit
➤ Direct drive of remaining capacity
LEDs
➤ Measurements automatically
compensated for rate and
temperature
➤ 16-pin narrow SOIC
Pin Connections
General Description
The bq2050H Lithium Ion Power
Gauge™ IC is intended for battery-
pack or in-system installation to
maintain an accurate record of
available battery capacity. The IC
monitors a voltage drop across a
sense resistor connected in series
between the negative battery termi-
nal and ground to determine
charge and discharge activity of
the battery. Compensations for bat-
tery temperature, self discharge,
and rate of discharge are applied to
the charge counter to provide avail-
able capacity information across a
wide range of operating conditions.
Battery capacity is automatically re-
calibrated, or “learned,” in the
course of a discharge cycle from full
to empty.
Nominal available capacity may be
directly indicated using a five-
segment LED display. These seg-
Pin Names
ments are used to graphically indi-
cate available capacity. The
bq2050H also supports a simple
single-line bidirectional serial link
to an external processor (common
ground). The 5kb HDQ bus interface
reduces communications overhead
in the external microcontroller.
Internal registers include available
capacity, temperature, scaled avail-
able energy, battery ID, battery
status, and Li-Ion charge FET
status. The external processor may
also overwrite some of the bq2050H
power gauge data registers.
The bq2050H can operate from the
batteries in the pack. The REF out-
put and an external transistor allow
a simple, inexpensive voltage regu-
lator to supply power to the circuit
from the cells.
LCOM
1
SEG1/PROG1
2
SEG2/PROG2
3
SEG3/PROG3
4
SEG4/PROG4
5
SEG5/PROG5
6
CFC
7
VSS
8
16
VCC
15
REF
14
PSTAT
13
HDQ
12
RBI
11
SB
10
DISP
9
SR
16-Pin Narrow SOIC
PN2050H1.eps
LCOM
LED common output
SEG₁/PROG₁ LED segment 1/
program 1 input
SEG₂/PROG₂ LED segment 2/
program 2 input
SEG₃/PROG₃ LED segment 3/
program 3 input
SEG₄/PROG₄ LED segment 4/
program 4 input
SEG₅/PROG₅ LED segment 5/
program 5 input
CFC
Charge FET control
output
V_SS
SR
DISP
SB
RBI
HDQ
PSTAT
REF
V_CC
System ground
Sense resistor input
Display control input
Battery sense input
Register backup input
Serial communications
input/output
Protector status input
Voltage reference output
Supply voltage
SLUS150–MAY 1999 D
1