BQ2054 Datasheet, PDF (5/16 Pages) Texas Instruments – Lithium Ion Fast-Charge IC

bq2054
Charge Status Display
Charge status is enunciated by the LED driver outputs
LED1–LED3. Three display modes are available in the
bq2054; the user selects a display mode by configuring
pin DSEL. Table 1 shows the three display modes.
The bq2054 does not distinguish between an over-
voltage fault and a “battery absent” condition. The
bq2054 enters the Fault state, enunciated by turning on
LED3, whenever the battery is absent. The bq2054,
therefore, gives an indication that the charger is on even
when no battery is in place to be charged.
Configuring the Display Mode and I_MIN
DSEL/LED2 is a bi-directional pin with two functions; it
is an LED driver pin as an output and a programming
pin as an input. The selection of pull-up, pull-down, or
no pull resistor programs the display mode on DSEL per
Table 1. The bq2054 latches the programming data
sensed on the DSEL input when any one of the following
three events occurs:
1. VCC rises to a valid level.
2. The bq2054 leaves the Fault state.
3. The bq2054 detects battery insertion.
The LEDs go blank for approximately 750ms (typical)
while new programming data is latched.
Table 1. bq2054 Display Output Summary
Mode
DSEL = 0
(Mode 1)
DSEL = 1
(Mode 2)
DSEL = Float
(Mode 3)
Charge Action State
Battery absent or over-voltage fault
Pre-charge qualification
Fast charging
Charge complete
Charge pending (temperature out of range)
Charging fault
Battery absent or over-voltage fault
Pre-charge qualification
Fast charge
Charge complete
Charge pending (temperature out of range)
Charging fault
Battery absent or over-voltage fault
Pre-charge qualification
Fast charge: current regulation
Fast charge: voltage regulation
Charge complete
Charge pending (temperature out of range)
Charging fault
LED1
Low
Flash
High
Low
X
X
Low
High
Low
High
X
X
Low
Flash
Low
High
High
X
X
LED2
Low
Low
Low
High
X
X
Low
High
High
Low
X
X
Low
Flash
High
High
Low
X
X
Note:
1
=
VCC;
0
=
VSS;
X
=
LED
state
when
fault
occurred;
Flash
=
1
6
sec.
low,
1
6
sec
high.
LED3
High
Low
Low
Low
Flash
High
High
Low
Low
Low
Flash
High
High
Low
Low
Low
Low
Flash
High
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