AAT2801
Multi-Mode Charge Pump for
White LED Backlight and Flash Applications
C3
1μF
C3+
C3-
4.5V
V
IN
OUT_FLSH
IN
CIN
COUT
1μF
1μF
Flash LED
AAT2801
Flash Enable
EN_FLSH
RL
RB
Flash Enable
Figure 2: Flash LED Driver with Gated Flash Application.
(VOUT - VF)
RB =
- RDS
IF
Where:
RB
=
Flash ballast resistor value in ohms (Ω)
RDS
VOUT
=
=
Flash gating mosfet on resistance
Regulated charge pump output voltage
(typically 4.5V)
VF
IF
=
=
Flash LED forward voltage at the
desired forward current
Desired flash LED forward current
2801.2006.04.1.3
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