MX841 Datasheet, PDF (1/6 Pages) IXYS Corporation – White LED Step-Up Converter

IXYS
MX841
White LED Step-Up Converter
Features:
• 1.1V to 5.5V Input Range
• 2 Amp Peak Switch Current
• High Efficiency > 80%
• 20V Maximum Output with Over-Voltage
Protection
• LED Intensity Control
• 1.0 MHz Fixed Frequency Switching
• 8 Lead SOIC Package
Applications:
• White LED Display Backlighting
- Low Voltage: Mobile Phones, PDA’s,
MP3 Players, Digital Cameras
- High Drive Current: Vehicle
Instrumentation Panels
Ordering Information
Part No. Description
17000-00TU SOIC-8 Standard Tube
17000-00TR SOIC-8 Standard T&R
17043-00TU SOIC-8 Exposed Pad Tube
17043-00TR SOIC-8 Exposed Pad T&R
Qty
100
2500
100
2500
General Description
The MX841 is a fixed frequency, constant current
source step-up DC/DC converter. The output current
is directly regulated making the MX841 ideal for
driving series connected white light emitting diodes
(LED’s) in backlight applications. The MX841
powers up to 3 series white LED’s at 1.1V, and 20
series/parallel white LED’s at 5.0V.
The MX841 features a 1.0MHz switching frequency
to accommodate the use of small capacitors and a
small inductor necessary in size sensitive portable
applications. Light intensity and shutdown are
conveniently controlled by a single analog voltage.
Power efficiency and battery life are extended
through the use of a high voltage, low R_DSON N-
channel MOSFET switch.
The MX841 is designed to operate over a
temperature range of -40°C to +85°C, and is
available in an SOIC-8 Package, with or without an
Exposed Pad in Tube or on Tape and Reel.
(Alternate package types available upon request).
Functional Block Diagram
VDD
SW SW
osc
CTL/SLEEP
Analog
Gnd
err amp/
comparator
Switch
Gnd
sleep det
driver
bias gen
band gap
+
compare
OVD
Isense
Typical Application
Vbattery
Vboost
5
1
4
6
OVD
CTRL
7 CTL/
SLEEP
MX841
Isense ⁸
Analog
GND
2
Switch
GND
3
Rsense
MX841
Drawing No. 17023
1
Preliminary
03/10/05
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