MAX8900A MAXIM [Maxim Integrated Products], MAX8900A Datasheet - Page 19
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MAX8900A
Manufacturer Part Number
MAX8900A
Description
Manufacturer
MAXIM [Maxim Integrated Products]
Datasheet
1.MAX8900A.pdf
(35 pages)
Figure 6. Li+/Li-Poly Charge Profile
to enable the MAX8900_. CEN has an internal 200kI
pulldown resistor. When disabled, the MAX8900_ supply
current is reduced, the step-down converter high-side and
low-side switches are off, and the AVL is disabled.
In many systems, there is no need for the system control-
ler (typically a microprocessor (FP)) to disable the char-
ger because the MAX8900_ independently manages the
charger. In these situations, CEN can be connected to
ground or left unconnected. Note: if CEN is permanently
connected to ground or left unconnected, the input
power must be cycled to escape from a timer fault state
(see Figures 7 and 8 for more information).
Rating and JEITA Battery Temperature Monitoring
1.2A Switch-Mode Li+ Chargers with ±22V Input
I
CHG P
I
DBAT +
V
V
V
BATREG
PQUTH
V
PQLTH
I
DBAT
DBAT
I
SET
I
I
PQ
PQ
0
TIME
TIME
V
to operate when CEN is pulled low. For example, if CEN is
low and the MAX8900_ is operating with V
< V
nonoperating condition.
The MAX8900_ utilizes several charging states to safely
and quickly charge batteries as shown in Figure 7.
Figure 6 shows an exaggerated view of a Li+/Li-Poly
battery progressing through the following charge states
when the die and battery are close to room temperature:
dead battery è prequalification è fast-charge è top-off
è done.
IN
must be greater than V
IN
< V
UVLO-RISING
, then toggling CEN results in a
UVLO-RISING
Charger States
for the MAX8900_
UVLO-FALLING
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