Datasheet

LTC4160/LTC4160-1
16
41601fa
+
–
+
+
–
0.3V
1.18V
3.6V
CLPROG
I
SWITCH
/N
+
–
+
–
15mV
OmV
IDEAL
DIODE
PWM AND
GATE DRIVE
AVERAGE V
BUS
OUTPUT
CURRENT LIMIT
CONTROLLER
V
BUS
VOLTAGE
CONTROLLER
V
OUT
VOLTAGE
CONTROLLER
+
–
5.1V
17
IDGATE
10
V
OUT
12
SW
3.5V TO
(BAT + 0.3V)
TO SYSTEM LOAD
SINGLE CELL
Li-Ion
41601 F03
14
BAT
BATTERY POWER
11
TO USB
OR WALL
ADAPTER
13
+
2
OVSENS
V
BUS
1
OVGATE
+
–
6V
OVERVOLTAGE PROTECTION
×2
+
–
+
–
1V
BATTERY CHARGER
I
BAT
/1000
+
–
V
FLOAT
+
–
PROG
8
OPERATION
current when the NMOS switch is on. This will cause the
inductor current to run away and the voltage on CLPROG
to rise. When CLPROG reaches 1.2V the switching of the
synchronous PMOS is terminated and V
OUT
is applied
statically to its gate. This ensures that the inductor current
will have sufficient negative slope during the time current
is flowing out of the V
BUS
pin. The PMOS will resume
switching when CLPROG drops down to 1.15V.
The PMOS switch is enabled when V
BUS
rises above
V
OUT
+ 180mV and is disabled when it falls below
V
OUT
+ 70mV to prevent the inductor current from run-
ning away when not in current limit. If the PMOS switch is
disabled for more than 7.2ms then the switcher will shut
off, the FAULT pin will go low and a short circuit fault will be
declared. To re-enable step-up mode, the ENOTG pin, with
ID high, must be cycled low and then high or the ID pin, with
ENOTG grounded, must be cycled high and then low.
Ideal Diode(s) from BAT to V
OUT
The LTC4160/LTC4160-1 each have an internal ideal diode
as well as a controller for an external ideal diode. Both the
internal and the external ideal diodes are always on and
will respond quickly whenever V
OUT
drops below BAT.
If the load current increases beyond the power allowed
from the bidirectional switching regulator, additional
power will be pulled from the battery via the ideal diode(s).
Furthermore, if power to V
BUS
(USB or wall adapter) is
removed, then all of the application power will be provided
by the battery via the ideal diode(s). The ideal diode(s) will
prevent V
OUT
from drooping with only the storage capaci-
tance required for the bidirectional switching regulator. The
internal ideal diode consists of a precision amplifier that
activates a large on-chip P-channel MOSFET whenever
Figure 4. Ideal Diode V-I Characteristics
Figure 3. PowerPath Block Diagram – USB On-The-Go
FORWARD VOLTAGE (mV) (BAT – V
OUT
)
0
CURRENT (mA)
600
1800
2000
2200
120
240
300
41601 F04
200
1400
1000
400
1600
0
1200
800
60
180
360
480420
VISHAY Si2333
OPTIONAL EXTERNAL
IDEAL DIODE
LTC4160/
LTC4160-1
IDEAL DIODE
ON
SEMICONDUCTOR
MBRM120LT3