BQ2954 Datasheet, PDF (1/18 Pages) Texas Instruments – Lithium Ion Charge Management IC with Integrated Switching Controller

bq2954
Lithium Ion Charge Management IC
with Integrated Switching Controller
Features
➤ Safe charge of Li-Ion battery
packs
➤ Pulse-width modulation control
for current and voltage reg-
ulation
➤ Programmable high-side/low-side
current-sense
➤ Fast charge terminated by se-
lectable minimum current; safety
backup termination at maximum
time
➤ Pre-charge qualification detects
shorted or damaged cells and
conditions battery
➤ Charging continuously qualified
by temperature and voltage limits
➤ Direct LED control outputs to
display charge status and fault
conditions
General Description
The bq2954 Li-Ion Charge-Manage-
ment IC uses a flexible pulse-width
modulation regulator to control volt-
age and current during charging.
The regulator frequency is set by an
external capacitor for design flexi-
bility. The switch-mode design mini-
mizes power dissipation.
For safety, the bq2954 inhibits fast
charging until the battery voltage
and temperature are within config-
ured limits. If the battery voltage is
less than the low-voltage threshold,
the bq2954 provides low-current
conditioning of the battery.
For charge qualifiction, the bq2954
uses an external thermistor to mea-
sure battery temperature. Charging
begins when power is applied or the
battery is inserted
The bq2954 charges a battery in two
phases. First a constant-current
phase replenishes approximately
70% of battery capacity. Then a volt-
age-regulation phase completes the
battery charge.
The bq2954 provides status indica-
tions of all charger states and faults
for accurate determination of the
battery and charge-system condi-
tions.
Pin Connections
Pin Names
TM
TM
1
CHG
2
BAT
3
VCOMP
4
ICOMP
5
ITERM
6
SNS
7
TS
8
16
LED2/DSEL
CHG
15
LED1/CSEL
BAT
14
MOD
VCOMP
13
VCC
12
VSS
11
LCOM
10
BTST
ICOMP
ITERM
SNS
9
TPWM
TS
16-Pin Narrow
DIP or SOIC
PN295401.eps
Time-out programming
input
Charge active output
Battery voltage input
Voltage loop comp input
Current loop comp input
Minimum current
termination select input
Sense resistor input
Temperature sense input
TPWM
BTST
LCOM
VSS
VCC
MOD
LED1/
CSEL
LED₂/
DSEL
Regulator timebase input
Battery test output
Common LED output
System ground
5.0V± 10% power
Modulation control
output
Charge status output 1/
Charge sense select
input
Charge status output 2/
Display select input
SLUS064–OCTOBER 1998 B
1