LX1993 Datasheet, PDF (1/12 Pages) Microsemi Corporation – High Efficiency LED Driver

INTEGRATED PRODUCTS
LX1993
High Efficiency LED Driver
PRODUCTION
DESCRIPTION
The LX1993 is a high efficiency
step-up boost converter that features a
psuedo-hysteretic pulse frequency
modulation topology for driving
white or color LEDs in backlight or
frontlight systems. Designed for
maximum efficiency, reduced board
size, and minimal cost, the LX1993 is
ideal for PDA and digital camera
applications. The LX1993 features an
internal N-Channel MOSFET and
control circuitry that is optimized for
portable system design applications.
The LX1993 promotes improved
performance in battery-operated
systems by operating with a quiescent
supply current 70µA (typical) and a
shutdown current of less than 1µA.
The input voltage range is from 1.6V
to 6.0V thus allowing for a broad
selection of battery voltage
applications and start-up is
guaranteed at 1.6V input.
The LX1993 is capable of switching
currents in excess of 300mA and the
output current is readily programmed
using one external current sense
resistor in series with the LEDs. This
configuration provides a feedback
signal to the FB pin thus maintaining
constant output current regardless of
varying LED forward voltage (V_F).
The LX1993 provides an additional
feature for simple dynamic adjustment
of the output current (i.e., up to 100%
of the maximum programmed current).
Designers can make this adjustment by
generating an analog reference signal
or a PWM signal applied directly to
the ADJ pin and any PWM amplitude
is readily accommodated via a single
external resistor. The LX1993 is
available in the 8-Pin MSOP and thus
requires a very small PCB area.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
PRODUCT HIGHLIGHT
KEY FEATURES
ƒ > 80% Maximum Efficiency
ƒ 70µA Typical Quiescent Supply
Current
ƒ Externally Programmable Peak
Inductor Current Limit For
Maximum Efficiency
ƒ Logic Controlled Shutdown
ƒ < 1µA Shutdown Current
ƒ Dynamic Output Current
Adjustment Via Analog
Reference Or Direct PWM Input
ƒ 8-Pin MSOP Package
APPLICATIONS
ƒ Pagers
ƒ Wireless Phones
ƒ PDAs
ƒ Handheld Computers
ƒ LED Driver
ƒ Digital Camera Displays
Li-Ion
ON OFF
SW
IN
SHDN
OUT
LX1993
FB
ADJ
CS
GND
Copyright © 2000
Rev. 1.0b, 2005-03-03
PACKAGE ORDER INFO
T_A (°C)
Plastic MSOP
DU _8-Pin
RoHS Compliant / Pb-free
Transition DC: 0432
0 to 70
LX1993CDU
Note: Available in Tape & Reel. Append the letters “TR” to the part
number. (i.e. LX1993CDU-TR)
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
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