LTC4066 LINER [Linear Technology], LTC4066 Datasheet - Page 16

• Manufacturer Part Number: LTC4066
• Description: USB Power Controller and Li-Ion Linear Charger with Low Loss Ideal Diode
• Manufacturer: LINER [Linear Technology]

LTC4066/LTC4066-1
APPLICATIONS INFORMATION
In USB applications, the minimum value for R
should be 2.1k. This will prevent the application current
from exceeding 500mA due to LTC4066/LTC4066-1 toler-
ances and quiescent currents. A 2.1k CLPROG resistor will
give a typical current limit of 476mA in high power mode
(HPWR = 1) or 95mA in low power mode (HPWR = 0).
V
< I
to the following equation:
For best stability over temperature and time, 1% metal
fi lm resistors are recommended.
Ideal Diode from BAT to OUT
If a battery is the only power supply available or if the load
current exceeds the programmed input current limit, then
the battery will automatically deliver power to the load via
an ideal diode circuit between the BAT and OUT pins. The
16
CLPROG
CL
I
IN
then V
=
R
V
will typically servo to 1V; however, if I
CLPROG
CLPROG
CLPROG
• 1000
will track the input current according
Figure 3. LTC4066/LTC4066-1 vs Schottky Diode Forward Voltage Drop
I
I
MAX
FWD
0
V
FWD
SLOPE: 1/R
OUT
SLOPE: 1/R
LTC4066
CLPROG
FWD
+ I
FORWARD VOLTAGE (V)
BAT
DIO(ON)
SCHOTTKY
ideal diode circuit (along with the recommended 4.7μF
capacitor on the OUT pin) allows the LTC4066/LTC4066-1
to handle large transient loads and wall adapter or USB
V
large bulk capacitors. The ideal diode responds within a
few microseconds and prevents the OUT pin voltage from
dipping below the BAT pin voltage by more than 50mV.
Forward regulation for the ideal diode from BAT to OUT
has three operational ranges, depending on the magni-
tude of the diode load current. For small load currents,
the LTC4066/LTC4066-1 will provide a constant voltage
drop; this operating mode is referred to as “constant
V
drop will increase linearly with the current with a slope of
1/R
R
I
operating mode is referred to as “constant I
The characteristics for parameters R
I
MAX
FWD
BUS
ON
ON
DIODE
DIO(ON)
” regulation. As the current exceeds I
” regulation. As the current increases further, exceeding
, the forward voltage drop will increase rapidly; this
are specifi ed with the aid of Figure 3.
connect/disconnect scenarios without the need for
; this operating mode is referred to as “constant
CONSTANT
I
CONSTANT
R
CONSTANT
V
ON
ON
ON
4066 F03
FWD
, R
FWD
ON
ON
” regulation.
the voltage
, V
FWD
4066fc
and