SC619_08 Datasheet, PDF (1/13 Pages) Semtech Corporation – Charge Pump Flash LED Driver with Safety Timer

SC619
Charge Pump Flash LED
Driver with Safety Timer
POWER MANAGEMENT
Features
„ Flash and spotlight — two selectable modes
„ Flash mode — up to 700mA output
„ Flash mode — 500mA max output (over rated voltage,
temperature, and load conditions)
„ Flash mode safety timer shut-off — 1 second
„ Spotlight mode set to 20% of flash current
„ Spotlight mode — up to 140mA output
„ Spotlight mode —1x mode (under most conditions)
for best efficiency
„ Input range — 3.0V to 5.25V
„ External flash control pin for synchronization to a cam-
era module or graphics controller
„ Short-circuit, over-voltage, and over-temperature pro-
tection
„ Soft-start functionality
„ Separate flash and spotlight control inputs for maxi-
mum versatility
„ Ultra-thin package MLPD-UT-10 — 3mm x 3mm x
0.6mm
Applications
„ Mobile camera phones
„ Digital cameras
„ PDAs with built-in cameras
Description
The SC619 is a high-current charge pump designed spe-
cifically for use with white LEDs used in camera flash
applications. Only two small bucket capacitors are required
to develop the output drive, providing a low EMI solution
compared to inductive boost regulators.
The SC619 has two modes of operation: flash mode and
spotlight mode. In flash mode, the SC619 is capable of
delivering 500mA of regulated current for a duration of
500ms or up to 700mA for a reduced duration. A safety
timer is also included to ensure the LED cannot be left on
indefinitely and overheat. In spotlight mode the SC619
outputs 20% of the flash mode current and can remain
enabled continuously.
An external resistor is connected in series with the LED to
set the current. In flash mode, this resistor can dissipate
up to 175mW, reducing the power dissipation require-
ment of the SC619. The flash input overrides the control
input to make sure the flash function is activated .
The SC619 ultra-thin package provides both a low profile
and high thermal efficiency.
Typical Application Circuit
V_BAT
10μF
1μF
1μF
FLASH
CTRL
SC619
VIN
VOUT
1μF
C1+
GND
C1-
ISET
C2+
CTRL
C2-
FLASH
White LED
R_SET
February 8, 2008
1