Datasheet

MAX8903A–E/G/H/J/N/Y
2A 1-Cell Li+ DC-DC Chargers
for USB and Adapter Power
20
Maxim Integrated
While in fast-charge mode, a large system load or device
self-heating may cause the MAX8903_ to reduce charge
current. Under these circumstances, the fast-charge
timer is slowed by 2x if the charge current drops below
50% of the programmed fast-charge level, and suspend-
ed if the charge current drops below 20% of the pro-
grammed level. The fast-charge timer is not affected at
any current if the charger is regulating the BAT voltage
at V
BATREG
(i.e., the charger is in voltage mode).
t
C
F
t
C
PREQUAL
CT
FST CHG
CT
=×
µ
=×
33
015
660
min
.
min
-
0015
15 8903
.
( /////)
µF
tsMAXADHJNY
t
TOP OFF
TO
-
=
PPOFF
CT
C
F
MAX B E G
-
=×132
015
8903min
.
(//)
µ
FAULT
UOK AND/OR DOK = LOW
CHG = HIGH IMPEDANCE
FLT = LOW
I
CHG
= 0mA
PREQUALIFICATION
UOK AND/OR DOK = LOW
CHG = LOW
FLT = HIGH IMPEDANCE
0 < V
BAT
< V
BATPQ
I
CHG
≤ I
CHGMAX
/10
DONE
UOK AND/OR DOK = 0
CHG = HIGH IMPEDANCE
FLT = HIGH IMPEDANCE
V
BATREG
+ V
RSTRT
< V
BAT
< V
BATREG
I
CHG
= 0mA
FAST-CHARGE
UOK AND/OR DOK = LOW
CHG = LOW
FLT = HIGH IMPEDANCE
V
BATPQ
< V
BAT
< V
BATREG
I
CHG
≤ I
CHGMAX
NOT READY
UOK AND DOK = HIGH IMPEDANCE
CHG = HIGH IMPEDANCE
FLT = HIGH IMPEDANCE
I
CHG
= 0mA
TIMER > t
PREQUAL
V
BAT
> V
BATPQ
RESET TIMER
V
BAT
< V
BATPQ
- 180mV
RESET TIMER = 0
I
CHG
< I
TERM
AND V
BAT
= V
BATREG
AND THERMAL
OR INPUT LIMIT
NOT EXCEEDED;
RESET TIMER
I
CHG
> I
TERM
RESET TIMER
V
BAT
< V
BATREG
+ V
RSTRT
RESET TIMER
TIMER > t
TOP-OFF
UOK AND/OR DOK = LOW
CEN = 0
RESET TIMER
CEN = HI OR
REMOVE AND RECONNECT
THE INPUT SOURCE(S)
ANY STATE
TOGGLE CEN OR
REMOVE AND RECONNECT
THE INPUT SOURCE(S)
TIMER > t
FSTCHG
(TIMER SLOWED BY 2x IF
I
CHG
< I
CHGMAX
/2, AND
PAUSED IF I
CHG
< I
CHGMAX
/5 WHILE V
BAT
< V
BATREG
)
TOP-OFF
UOK AND/OR DOK = LOW
CHG = HIGH IMPEDANCE
FLT = HIGH IMPEDANCE
V
BAT
= V
BATREG
I
CHG
= I
TERM
TEMPERATURE SUSPEND
I
CHG
= 0mA
UOK OR DOK PREVIOUS STATE
CHG = HIGH IMPEDANCE
FLT = HIGH IMPEDANCE
ANY CHARGING
STATE
THM NOT OK
TIMER SUSPEND
THM OK
TIMER RESUME
V
BAT
< V
BATPQ
- 180mV
RESET TIMER
Figure 6. MAX8903A Charger State Flow Chart