AT1313
High Efficiency, Constant Current
White-LED Driver
Feature
•Operating Voltage:2.5V~5.5V
•High Operating Frequency: 1.4MHz
•High Output Voltage: Up to 18V
•Shutdown Current <1µA
•18V Output Over-voltage protection
•Digital Dimming Control.
•Built-in Cycle-by Cycle Current-limiting.
•Built-in Soft-Start Function.
•0.2V Low Reference Voltage
•Tiny SOT-26 Package
Description
The AT1313 step-up converter drives white LEDs
with a constant current to provide backlight in cell
phones, PDAs, and other hand-held devices. It
features allowing series connection of the white
LEDs so that the LED currents are identical for
uniform brightness. An enable input can be pulsed
repeatedly to adjust LED’s brightness. The fast 1.4
MHz current-mode PWM control allows for smaller
capacitor and inductor. Fault condition protection
uses cycle-by-cycle current limiting to sense
maximum inductor current, thermal protection and
over-voltage protection. Also included soft-start
eliminates inrush current during start-up. The 0.2V
low reference voltage minimized the power loss
across the current-setting resistor.
The AT1313 is available in 6-pin SOT-26 packages.
Application
• LED Module
• Compact Back Light Module
• Constant Current Source
Block Diagram
VIN
LX
ON/OFF
Control
Logic / PWM
Dimming
Control
VREF
+
Control Logic
FB
18V
VBG
+
-
Overvoltage
Protection
-
CTL
N
VREF
0.2V
VBG
1.23V
Soft-Start
EN
OVP
Current Limit
1.2A
+
-
CTL
GND
Aimtron reserves the right without notice to change this circuitry and specifications.
7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW:
http://www.aimtron.com.tw
10/31/2006 REV:2.0
Email:service@aimtron.com.tw
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AIMTRON [ AIMTRON TECHNOLOGY ]
