Datasheet

MAX8819A/MAX8819B/MAX8819C
PMIC with Integrated Chargers and Smart
Power Selector in a 4mm x 4mm TQFN
______________________________________________________________________________________ 17
Battery Charger
Figure 2 shows the typical Li+/Li-Poly charge profile for
the MAX8819_, and Figure 3 shows the battery charger
state diagram.
With a valid DC input that is not suspended, the battery
charger initiates a charge cycle once CEN is driven
high. It first detects the battery voltage. If the battery
voltage is less than the prequalification threshold
(3.0V), the charger enters prequalification mode and
charges the battery at 10% of the maximum fast-charge
current while deeply discharged. Once the battery volt-
age rises to 3.0V, the charger transitions to fast-charge
mode and applies the maximum charge current. As
charging continues, the battery voltage rises until it
approaches the battery regulation voltage (4.2V typ)
V
BATPRQ
V
BATREG
I
CHGMAX
I
PREQUAL
I
TOPOFF
0
PREQUALIFICATION
FAST-CHARGE
(CONSTANT CURRENT)
TOP-OFF
FAST-CHARGE
(CONSTANT VOLTAGE)
DONE
LOW
HIGH
IMPEDANCE
BATTERY VOLTAGEBATTERY CHARGE CURRENTCHG
Figure 2. Li+/Li-Poly Charge Profile