1.5A Step-Up Current Regulator for Flash LEDs
The AAT1290 has internal thermal protection circuitry to
disable the device if the power dissipation exceeds a
preset thermal limit. The junction over-temperature
threshold is 140°C with 15°C of temperature hysteresis.
During Flash or movie-mode operation, should an envi-
ronmental condition, flash current sink or the boost con-
verter cause the internal die temperature to rise above
140°C, the boost converter will be shut down. The boost
converter output operation will automatically recover
when the over-temperature fault condition is removed.
(Open LED, Open Circuit)
The AAT1290’s output voltage is limited by internal over-
voltage protection circuitry, which prevents damage to
the AAT1290 from open LED or open circuit conditions.
During an open circuit event, the boost converter output
will rise to the over-voltage protection (OVP) threshold
at 5.5V (typical). Upon sensing the OVP event, the boost
converter will be disabled to prevent damage to the
device. Once the open circuit fault condition is removed,
boost converter switching will resume.
Short Circuit Protection
The AAT1290 is equipped with an auto-disable feature
for the flash LED current sink. After the IC is enabled and
system start up commences, a test current of 2-3mA
(typical) is forced through the current sink. The current
sink will be disabled if the voltage of the SINK pin does
not drop to a predetermined threshold. This feature is
very convenient for disabling the current sink in the
event of the flash LED short-circuit failure. This small
test current is added to the set output current in both
Flash and movie mode conditions.
FLASH TIMES OUT
FLASH TIMES OUT
SET BY CT
No AS2C address programming shown.
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10 202106A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 26, 2012