下载
LT3593
1
3593f
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
1MHz White LED Driver with
Output Disconnect and One
Pin Current Programming
The LT
®
3593 is a step-up DC/DC converter designed to
drive up to ten white LEDs in series from a Li-Ion cell.
Series connection of the LEDs provides identical LED
currents and eliminates the need for ballast resistors. The
device features a unique high side LED current sense that
enables the part to function as a “one wire current source”
where the low side of the LED string can be returned to
ground anywhere.
Additional features include output disconnect in shutdown,
open LED protection and 1-pin shutdown/LED current
control. The CTRL pin is toggled to adjust the LED current
via an internal counter and a 5-bit DAC.
The LT3593 switches at 1MHz, allowing the use of tiny
external components. Constant frequency switching re-
sults in low input noise and a small output capacitor. The
LT3593 is available in the 6-lead DFN (2mm × 2mm) as
well as the 6-lead SOT-23 packages.
Li-Ion Driver for Ten White LEDs
n
Drives Up to Ten White LEDs from a 3V Supply
n
One Pin Shutdown and Current Programming
n
LEDs Disconnected in Shutdown
n
32:1 Linear Brightness Control Range
n
V
IN
Range: 2.7V to 5.5V
n
±5% Output Current Accuracy at Full Scale
n
Low Shutdown Current: 3µA
n
1MHz Switching Frequency
n
Requires Only 1µF Output Capacitor
n
Low Profi le 6-Lead DFN (2mm × 2mm × 0.75mm)
and 6-Lead SOT-23 Packages
n
Cell Phones
n
Digital Cameras
n
PDAs, Handheld Computers
n
MP3 Players
n
GPS Receivers
CTRL
V
IN
10µH
V
IN
3V TO 5V
3593 TA01a
LT3593
SHUTDOWN AND
CURRENT CONTROL
SW
CAP
LED
GND
1µF 1µF
Conversion Effi ciency
LED CURRENT (mA)
0
EFFI CIENCY (%)
90
70
50
80
60
40
30
10
3593 TA01b
20155
V
IN
= 3.6V
10 LEDs
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
页面指南
