Datasheet

LTC4055/LTC4055-1
22
4055fb
TYPICAL APPLICATIONS
USB Hosting Application: The LTC4055/LTC4055-1’s
IN1 and IN2 are Set Hi-Z by Pulling the SUSP Pin
Above 1.2V
In applications where the power is required to go back
out on to the USB V
BUS
the LTC4055/LTC4055-1 can be
confi gured to turn off its input power path, IN1 and IN2.
Forcing the SUSP input pin above 1.2V does this. Figure 6
shows the application circuit. The wall adapter or the battery
can still provide power to OUT, which in turn can provide
power to V
BUS
when commanded from the USB controller.
The ability to charge the battery is enabled when the wall
adapter is present.
+
IN1
IN2
WALL
SUSP
V
NTC
NTC
OUT
Li-Ion
CELL
500mA/100mA SELECT
SHUTDOWN
10μF
1μF
TIMER PROG
LTC4055
CLPROG GND
4055 F06
TO LDOs,
REGs, ETC
BAT
CHRG
ACPR
HPWR
SHDN
C
TIMER
0.1μF
R
PROG
100k
5V (NOM)
FROM USB
CABLE V
BUS
5V WALL
ADAPTER INPUT
R
CLPROG
105k
R1
34.8k
R2
10k
USB
CONTROLLER
R3
100k
NTC
100k
DC/DC
CONVERTER
EN
V
IN
V
OUT
Figure 6. USB Hosting Application