LTC4160-1 LINER [Linear Technology], LTC4160-1 Datasheet - Page 14

• Manufacturer Part Number: LTC4160-1
• Description: Switching Power Manager with USB On-The-Go And Overvoltage Protection
• Manufacturer: LINER [Linear Technology]

OPERATION
LTC4160/LTC4160-1
the programmed limit, CLPROG reaches 1.18V and power
delivered by the switching regulator is held constant.
The input current limit is programmed by the I
I
tings ranging from the USB suspend limit of 500μA up
to 1A for wall adapter applications. Two of these settings
are specifi cally intended for use in the 100mA and 500mA
USB application. Refer to Table 1 for current limit settings
using I
Table 1. USB Current Limit Settings Using I
When the switching regulator is activated, the average
input current will be limited by the CLPROG programming
resistor according to the following expression:
OR WALL
ADAPTER
14
LIM1
TO USB
I
VBUS
I
LIM1
0
0
1
1
pins. The input current limit has four possible set-
LIM0
=
I
and I
VBUSQ
I
LIM0
0
1
0
1
LIM1
13
17
1
2
V
CLPROG
OVGATE
OVSENS
I
SWITCH
BUS
+
1.18V
R
.
V
/N
CLPROG
CLPROG
USB SETTING
1x Mode (USB 100mA Limit)
10x Mode (Wall 1A Limit)
Low Power Suspend (USB 500μA Limit)
5x Mode (USB 500mA Limit)
Figure 1. Power Path Block Diagram – Power Available from USB/Wall Adapter
–
+
5V
CONTROLLER
OVERVOLTAGE PROTECTION
2
AVERAGE V
VOLTAGE
V
CURRENT LIMIT
CONTROLLER
BUS
–
+
•
(
h
+
–
BUS
CLPROG
INPUT
+ –
LIM0
GATE DRIVE
PWM AND
and I
+
6V
1
)
LIM1
V
CONTROLLER
OUT
LIM0
VOLTAGE
–
+
+
and
3.6V
0.3V
+ –
where I
LTC4160-1, V
current limit, R
resistor and h
rent at V
Refer to the Electrical Characteristics table for values of
h
tolerances, the USB specifi cation for the average input
current in 100mA or 500mA mode will not be violated,
provided that R
While not in current limit, the switching regulator’s
Bat-Track feature will set V
above the voltage at BAT. However, if the voltage at BAT
is below 3.3V, and the load requirement does not cause
the switching regulator to exceed its current limit, V
will regulate at a fi xed 3.6V, as shown in Figure 2. This
instant-on operation will allow a portable product to run
immediately when power is applied without waiting for the
battery to charge. If the load does exceed the current limit
at V
slightly below the battery voltage, indicated by the shaded
region of Figure 2.
CLPROG
BATTERY CHARGER
BUS
I
BAT
, V
/1000
VBUSQ
–
+
–
, V
BUS
+
OUT
1V
V
CLPROG
FLOAT
to the sample current delivered to CLPROG.
will range between the no-load voltage and
CLPROG
is the quiescent current of the LTC4160/
CLPROG
CLPROG
CLPROG
OmV
IDEAL
DIODE
15mV
and I
is the CLPROG servo voltage in
is the ratio of the measured cur-
–
+
is 3.01k or greater.
is the value of the programming
USB INPUT
BATTERY POWER
VBUSQ
+
–
OUT
IDGATE
PROG
V
OUT
BAT
. Given worst-case circuit
SW
to approximately 300mV
14
12
10
11
8
+
SINGLE CELL
Li-Ion
41601 F01
3.5V TO
(BAT + 0.3V)
TO SYSTEM LOAD
41601f
OUT