LTC4063 LINER [Linear Technology], LTC4063 Datasheet - Page 17

• Manufacturer Part Number: LTC4063
• Description: Standalone Linear Li-Ion Charger with Micropower Low Dropout Linear Regulator
• Manufacturer: LINER [Linear Technology]

APPLICATIO S I FOR ATIO
USB and Wall Adapter Power
The LTC4063 allows charging from both a wall adapter
and a USB port. Figure 9 shows how to combine wall
adapter and USB power inputs. A P-channel MOSFET,
MP1, is used to prevent back conducting into the USB port
when a wall adapter is present and a Schottky diode, D1,
is used to prevent USB power loss through the 1k pull-
down resistor.
U
U
I
I
CHG
CHG
USB POWER
ADAPTER
5V WALL
= 800mA
= 500mA
W
Figure 9. Combining Wall Adapter and USB Power
MP1
U
1k
D1
V
GND
CC
LTC4063
MN1
PROG
IDET
Most wall adapters can supply more current than the
500mA limited USB port. Therefore, an N-channel MOSFET,
MN1, and an extra 3.3k program resistor are used to
increase the charge current to 800mA when the wall
adapter is present.
BAT
3.3k
2k
1.25k
+
4063 F09
Li-Ion
BATTERY
SYSTEM
LOAD
LTC4063
17
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