AAT1282 Datasheet, PDF (10/22 Pages) Skyworks Solutions Inc. – 2A Driver for High Intensity LED Camera Flash

DATA SHEET
AAT1282
2A Driver for High Intensity LED Camera Flash
current ratio can be set using the AAT1282’s I²C-compliant
interface. The movie-mode current level can be adjusted
in 16 steps using a logarithmic scale. The maximum flash
safety timer can be externally set by CT, and the timer
can be programmed from the maximum value in 16 linear
steps through I²C-compliant interface. The FLEN signal
takes priority over movie-mode operation. Lastly, the EN
pin must be toggled low-to-high to enable the AAT1282
to accept any I²C programming instructions.
Over-Temperature Protection
Thermal protection disables the AAT1282 when internal
power dissipation becomes excessive, as it disables both
MOSFETs. The junction over-temperature threshold is
140°C with 15°C of temperature hysteresis. The output
voltage automatically recovers when the over-tempera-
ture fault condition is removed.
Operating Diagram
Over-Voltage Protection
(Open LED, Open Super Capacitor)
The AAT1282’s output voltage is limited by internal over-
voltage protection circuitry, which prevents damage to
the AAT1282 from an open super capacitor condition.
During this condition, the output voltage rises and
reaches 5.5V (typical), preventing the output voltage
from rising higher. Once the open super capacitor condi-
tion is removed, charging of the super capacitor will
resume. The controller will return to normal operation
and maintain an average output voltage.
If one LED channel accidently becomes open, the remain-
ing LED channel of AAT1282 will still work, but may not
be regulated to the desired current.
Device Start up and Shutdown
The AAT1282 is put into operation when EN is set high. It
is put into a shutdown mode when EN is set to GND. In
the shutdown mode, AAT1282 draws less than 1μA from
the battery. All data and register contents are cleared
(reset to the default value) during shutdown. During start
up of this LED driver, the peak current is limited in order
to avoid high peak current drawn from the battery.
ENABLE
5.5V
VOUT = SuperCap voltage
FLASH ENABLE
t_CT
LED CURRENT
Turn on LEDs in
Movie Mode
controlled by I²C
interface
Flash times out
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
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202305C • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013