BQ2004E_07 Datasheet, PDF (2/19 Pages) Texas Instruments – Fast-Charge ICs

bq2004E/H
Pin Descriptions
SNS
DCMD
DSEL
VSEL
TM1–
TM2
TCO
TS
BAT
Discharge-before-charge control input
The DCMD input controls the conditions
that enable discharge-before-charge. DCMD
is pulled up internally. A negative-going
pulse on DCMD initiates a discharge to end-
of-discharge voltage (EDV) on the BAT pin,
followed by a new charge cycle start. Tying
DCMD to ground enables automatic
discharge-before-charge on every new charge
cycle start.
Display select input
This three-state input configures the charge
status display mode of the LED1 and LED2 out-
puts and can be used to disable top-off and
pulsed-trickle. See Table 2.
Voltage termination select input
This three-state input controls the voltage-
termination technique used by the
bq2004E/H. When high, PVD is active.
When floating, -∆V is used. When pulled low,
both PVD and -∆V are disabled.
Timer mode inputs
LED1–
LED2
Vss
VCC
MOD
DIS
TM1 and TM2 are three-state inputs that
configure the fast charge safety timer, voltage
termination hold-off time, “top-off”, and
trickle charge control. See Table 1.
Temperature cut-off threshold input
Input to set maximum allowable battery
temperature. If the potential between TS
and SNS is less than the voltage at the TCO
input, then fast charge or top-off charge is ter-
minated.
Temperature sense input
Input, referenced to SNS, for an external
thermister monitoring battery temperature.
Battery voltage input
BAT is the battery voltage sense input, refer-
enced to SNS. This is created by a high-
impedance resistor-divider network con-
nected between the positive and the negative
terminals of the battery.
INH
Charging current sense input
SNS controls the switching of MOD based on
an external sense resistor in the current
path of the battery. SNS is the reference po-
tential for both the TS and BAT pins. If
SNS is connected to VSS, then MOD switches
high at the beginning of charge and low at
the end of charge.
Charge status outputs
Push-pull outputs indicating charging
status. See Table 2.
Ground
VCC supply input
5.0V, ±10% power input.
Charge current control output
MOD is a push-pull output that is used to
control the charging current to the battery.
MOD switches high to enable charging cur-
rent to flow and low to inhibit charging
current flow.
Discharge control output
Push-pull output used to control an external
transistor to discharge the battery before
charging.
Charge inhibit input
When low, the bq2004E/H suspends all
charge actions, drives all outputs to high im-
pedance, and assumes a low-power opera-
tional state. When transitioning from low to
high, a new charge cycle is started.
2