Data Sheet

© 2012 Fairchild Semiconductor Corporation www.fairchildsemi.com
FPF3040 • Rev. 2.4.3 11
FPF3040 — IntelliMAX™ 18 V-Rated Dual Input Single Output Power-Source-Selector Switch
Operation and Application Information
The FPF3040 is a 18 V, 2 A-rated, Dual-Input Single-
Output (DISO) load switch with slew-rate-controlled,
low-on-resistance, based-on-N-channel MOSFET. The
input operating range is from 4 V to 6.5 V at V
BUS
and
from 4 V to 10.5 V at V
IN
. The internal circuitry is
powered from the highest voltage source among V
IN
,
V
BUS
, and V
EN
.
Input Power Source Selection
Input power source can be selected by V
IN_SEL
and
DF_IN, respectively, depending on EN state. When EN
is HIGH, the input source is selected by V
IN_SEL
regardless of DF_IN. If V
IN_SEL
is LOW, V
BUS
is selected.
If V
IN_SEL
is HIGH, V
IN
is selected.
Table 2. Input Power Selection by VIN_SEL
EN
V
IN
>UVLO
V
BUS
>UVLO
V
IN_SEL
DF_IN
V
OUT
HIGH
X
X
LOW
X
V
BUS
HIGH
X
X
HIGH
X
V
IN
When EN is LOW, the input source is selected by
DF_IN and the number of valid input sources. If only
one input source is valid, or more than UVLO, the
source is selected automatically, regardless of DF_IN,
to make a charging path in case the battery is depleted.
If both V
BUS
and V
IN
have valid input sources, the input
source is selected by DF_IN. If DF_IN is LOW, V
IN
is
selected. If DF_IN is HIGH or floating, V
BUS
is selected.
DF_IN is biased HIGH with an internal 1 µA pull-up
current source.
Table 3. Input Power Selection by DF_IN
EN
V
IN
>UVLO
V
BUS
>UVLO
V
IN_SEL
DF_IN
V
OUT
LOW
YES
NO
HIGH
X
V
IN
LOW
NO
YES
LOW
X
V
BUS
LOW
YES
YES
LOW
Floating
V
BUS
LOW
YES
YES
HIGH
LOW
V
IN
LOW
NO
NO
X
X
Floating
V
IN_SEL
can be the status output to indicate which input
power source is used during EN is LOW. If V
IN
is used,
V
IN_SEL
shows high. If V
BUS
is used, V
IN_SEL
shows LOW.
The voltage level of HIGH signal is 5.3 V if any one of
V
IN
, V
BUS
or EN is higher than 5.3 V. The signal is
highest voltage among V
IN
, V
BUS
, and V
EN
if none of
them is higher than 5.3 V.
EN Voltage for Control Logic Power
Supply
Internal control logic is powered from the highest
voltage among V
IN
, V
BUS
, and V
EN
. If valid V
IN
or V
BUS
higher than UVLO is applied, ON/OFF control by EN
should be accomplished with V
IH
/V
IL
. If EN powers the
internal control block without valid V
IN
and V
BUS
, more
than 2.5 V is required on the EN pin to operate properly.
Over-Voltage Protection (OVP)
FPF3040 has over-voltage protection at both V
IN
and
V
BUS
. If V
IN
or V
BUS
is higher than 12 V or 7.5 V,
respectively, the power switch is off until input voltage is
lower than the over-voltage trip level by hysteresis
voltage of 0.5 V.
Reverse Power Supply for OTG
FPF3040 has a bi-directional switch so reverse power is
allowed for On-The-Go (OTG) operation. Even if both V
IN
and V
BUS
are not available, reverse power can be also
supported if internal control circuitry is powered by EN.
Reverse-Current Blocking
FPF3040 supports reverse-current blocking during EN
LOW and an unselected channel.
Thermal Shutdown
During FPF3040 thermal shutdown, the power switch is
turned off if junction temperature reaches over 150°C to
avoid damage.
Wireless Charging System
FPF3040 can be used for an input power selector
supporting Travel Adaptor (TA) and Wireless Charging
(WC) with a single-input-based battery charger or Power
Management IC (PMIC), including a charging block as
shown in Figure 31. The system can recognize an input
power source change between 5 V TA and 5 V WC
without detection circuitry because FPF3040 has a
100 ms transition delay. OTG Mode can be supported
without an additional power path, such as a MOSFET.
Travel Adaptor
(5V)
Wireless Charging
(5V)
FPF3040
Li-Pol
BAT
System
PMIC
with
BAT Charger &
OTG Boost &
Power Path
V
BUS
V
IN
V
OUT
EN, V
IN_SEL
, DF_IN
V
IN_SEL
, Other_V
IN
_Ava
Figure 31. Block Diagram of Input Power Selector for Wireless Charging System