AAT1401 Datasheet, PDF (9/19 Pages) List of Unclassifed Manufacturers – FOUR-CHANNEL DIGITAL STILL CAMERA POWER SUPPLY

DATA SHEET
AAT1401
Serial LED Driver with Filtered PWM and 32-Step S2C Dimming Control
Functional Block Diagram
LX
PGND
IN
Control
OVP
OSC
OVP
COMP
EN/SET
PWM
Interface
REF
RSET
CS
GND
Functional Description
The AAT1401 is a small size, high efficiency, current mode
controlled step-up converter LED driver for up to 6 white
LEDs. It is available with up to 28V output voltage to allow
up to 6 series connected LEDs to be driven with currents
up to 31mA. The device uses a single current sink to
regulate the LED current by controlling the output volt-
age. The maximum LED current is programmed by an
external resistor with range from 10mA to 31mA. The LED
current dimming is controlled via one of two options,
using either the S²Cwire 32-step single-wire interface or
PWM control.
The over-voltage protection function is designed to pro-
tect the boost converter during the fault of the open
circuit of the LED string. The over-temperature function
is targeted to protect the converter if an over-tempera-
ture fault occurs. The AAT1401 will recover to normal
operation automatically when the OVP or OTP fault is
removed.
Soft Start / Enable
The AAT1401 is enabled by EN/SET pulled to high after
power on with a certain delay time. Internal soft start
circuitry limits the input inrush current and eliminates
output voltage overshoot. When ENSET is pulled low the
AAT1401 enters a low-power, non-switching state. The
total input current during shutdown is less than 1μA. An
external diode limits V_OUT to the level of V_IN during shut-
down. The diode consumes a small amount of additional
input current depending on the OVP resistor divider
value.
Over-Temperature Protection
Thermal protection disables the AAT1401 when internal
dissipation becomes excessive. Thermal protection dis-
ables the power MOSFET. The junction over-temperature
threshold is 155°C with 15°C of temperature hysteresis.
The output voltage automatically recovers when the
over-temperature fault condition is removed.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
202113A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 27, 2012
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