MAX8845Z Maxim Integrated Products, MAX8845Z Datasheet - Page 7

• Manufacturer Part Number: MAX8845Z
• Description: 28V Linear Li+ Battery Chargers
• Manufacturer: Maxim Integrated Products

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The MAX8845Z/MAX8845Y chargers use voltage, cur-
rent, and thermal-control loops to charge a single Li+
cell and protect the battery (Figure 1). When a Li+ bat-
tery with a cell voltage below 2.5V is inserted, the
MAX8845Z/MAX8845Y chargers enter a prequalifica-
tion stage where it precharges that cell with 10% of the
Figure 1. MAX8845Z/MAX8845Y Functional Diagram
SETI
MIN
28V Linear Li+ Battery Chargers with Battery
IN
Detection and Overvoltage Protected Output
OVLO
V
IN
IN
DETBAT
BATT
_______________________________________________________________________________________
MAX8845Y
MAX8845Z
Detailed Description
REGULATOR
WITH OVP
LINEAR
I
MINREF
UVLO
VL
V
REF
REGULATOR
VL
GND
REFOK
REF
CURRENT SENSE,
OUTPUT DRIVER,
V
V
REF
AND LOGIC
L
EP
LOGIC
user-programmed fast-charge current (Figure 2). The
CHG indicator is driven low to indicate entry into the
prequalification state. When the battery voltage
exceeds 2.5V, the charger soft-starts as it enters the
fast-charge stage. The fast-charge current level is pro-
grammed through a resistor from SETI to GND. As the
battery voltage approaches 4.2V, the charging current
V
REF
POK
+115°C
TEMPERATURE
SENSOR
200kΩ
200kΩ
BATT
ABO (MAX8845Y ONLY)
EN
SAFEOUT
CHG
POK
ABO (MAX8845Z ONLY)
ABI
BATT
DETBAT
V
I/O
4.2V
Li+
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