AAT3119_07 ANALOGICTECH [Advanced Analogic Technologies], AAT3119_07 Datasheet - Page 14

• Manufacturer Part Number: AAT3119_07
• Description: High Efficiency 2X Charge Pump
• Manufacturer: ANALOGICTECH [Advanced Analogic Technologies]

If a "light" or "movie" mode is also needed along
with the flash function, this can be accomplished
with the addition of a second ballast resistor with a
flash function gating MOSFET switch as shown in
Figure 3. Refer to the following equations for the
calculation of flash and light resistors, R
Where:
R
V
V
I
14
F
OUT
F
L
=
=
=
=
Light mode ballast resistor value in
ohms (Ω)
Regulated charge pump output voltage
(typically 4.5V)
Flash LED forward voltage at the
desired forward current
Desired flash LED forward current in
the "light" mode
Enable
V
R
IN
L
=
(V
OUT
1μF
C
I
F
IN
- V
F
)
EN
IN
Figure 2: Flash LED Application.
AAT3119
F
GND
C
and R
1μF
FLY
OUT
L
.
4.5V
Where:
R
R
V
V
I
F
C
1μF
High Efficiency 2X Charge Pump
OUT
F
F
DS
OUT
=
=
=
=
=
Flash ballast resistor value in ohms (Ω)
Flash gating MOSFET on resistance
Regulated charge pump output voltage
(typically 4.5V)
Flash LED forward voltage at the
desired forward current
Desired flash LED forward current
R
R
F
F
=
(V
OUT
I
F
- V
Flash LED
F)
- R
AAT3119
DS
3119.2007.02.1.2