LTC4061 Datasheet, PDF (18/20 Pages) Linear Technology – Standalone Linear Li-lon Battery Charger with Thermistor Input

LTC4061
APPLICATIO S I FOR ATIO
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
1kΩ pull-down resistor.
Typically a wall adapter can supply more current than
the 500mA limited USB port. Therefore, an N-channel
MOSFET, MN1, and an extra 3.3kΩ program resistor are
used to increase the charge current to 800mA when the
wall adapter is present.
5V WALL
ADAPTER
I_CHG = 800mA
USB POWER
I_CHG = 500mA _MP1
D1
V_CC
BAT
LTC4061
I_DET
C/5 PROG
3.3k
SYSTEM
LOAD
+ _Li-Ion
BATTERY
1k
MN1
2k 1.25k
4061 F08
Figure 8. Combining Wall Adapter and USB Power
4061fa
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