BQ2054 Datasheet, PDF (2/16 Pages) Texas Instruments – Lithium Ion Fast-Charge IC

bq2054
Pin Descriptions
TS
TM
Time-out programming input
This input sets the maximum charge time.
The resistor and capacitor values are deter-
mined using Equation 5. Figure 7 shows the
resistor/capacitor connection.
TPWM
ICTL
Inrush current control output
ICTL is driven low during the fault or
charge-complete states of the chip. It is used
to disconnect the capacitor across the battery
pack terminals, preventing inrush currents
from tripping overcurrent protection fea-
tures in the pack when a new battery is in-
serted.
BAT
Battery voltage input
BAT is the battery voltage sense input. This
potential is generally developed using a
high-impedance resistor divider network
connected between the positive and the
negative terminals of the battery. See Fig-
ure 4 and Equation 1.
VCOMP Voltage loop compensation input
This input uses an external R-C network for
voltage loop stability.
ITERM
Minimum current termination select
This three-state input is used to set IMIN for
fast charge termination. See Table 2.
LCOM
MOD
LED1–
LED3
DSEL
ICOMP Current loop compensation input
This input uses an external R-C network for
current loop stability.
VCC
SNS
Charging current sense input
Battery current is sensed via the voltage de- ^VSS
veloped on this pin by an external sense re-
sistor, RSNS, connected in series with the
negative terminal of the battery pack. See
Equation 6.
Temperature sense input
This input is used to monitor battery tempera-
ture. An external resistor divider network sets
the lower and upper temperature thresholds.
See Figure 6 and Equations 3 and 4.
Regulation timebase input
This input uses an external timing capacitor
to ground to set the pulse-width modulation
(PWM) frequency. See Equation 7.
Common LED output
Common output for LED1–3. This output is
in a high-impedance state during initiali-
zation to read programming input on
DSEL.
Current-switching control output
MOD is a pulse-width modulated push/pull
output that is used to control the charging
current to the battery. MOD switches high
to enable current flow and low to inhibit cur-
rent flow.
Charger display status 1–3 outputs
These charger status output drivers are for
the direct drive of the LED display. Display
modes are shown in Table 1. These outputs are
tri-stated during initialization so that DSEL
can be read.
Display select input
This three-level input controls the LED1–3
charge display modes. See Table 1.
VCC supply
5.0V, ± 10% power
Ground
2