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White LED
(White Light Emitting Diodes) Circuits
White LEDs: #-B
C - KL - PQ - VW - ZLED Circuits Last Updated on:
Monday, October 03, 2011 06:08 PM
Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
White LED drive from 1.5V - How do you get 3.5 volts to drive a
white LED when you only have a 1.5v battery?.....(schematic / circuit
added 6/07)
White LED driver backlights LCD and keypad - 13-Nov-03 Issue of
EDN Designers widely use white LEDs to backlight color LCDs and
keypads in handheld devices, such as cell phones, MP3 players, GPS
navigators, and PDAs. Their spectrum and brightness represent near-ideal
light sources. One possible configuration for a phone or a phone/PDA
combination is to have a group of three LEDs to light the display and six
LEDs for the keypad..... [Design Idea by Fabien Franc, Catalyst
Semiconductor, Sunnyvale, CA]
White LED driver operates down to 1.2V supply voltage - 3-Sep-07 Issue of
EDNThis circuit beats commercially available LED drivers, which bottom out at 2.5V
input voltage, by operating at voltages as low as 1V..... [Design Idea by Dave
Wuchinich, Modal Mechanics, Yonkers, NY]
White LED driver provides 64 step logarithmic dimming - 10-Jun-04 Issue of
EDN The circuit of Figure 1 is designed for portable-power applications that
require white LEDs with adjustable, logarithmic dimming levels. The circuit drives as
many as four white LEDs from a 3.3V source and adjusts the total LED current from 1 to
106 mA in 64 steps of 1 dB each. The driver is a charge pump that mirrors the current
ISET (sourced from IC3's SET terminal] to produce a current o..... [Design Idea by
William Hadden, Maxim Integrated Products, Sunnyvale, CA]
White LED driver touts high efficiency - 12-Jun-03 Issue of EDN White
LEDs, the most recent addition to the LCD backlight, find common use in providing
backlight for color LCDs. Thanks to their size and white-light output, they appear in
small, portable devices with color displays, such as PDAs and cellular phones. Like
other LEDs, a white LED needs a constant-current source—typically, on the order of 15
to 20 mA..... [Design Idea by Dimitry Goder, Sipex Corp, San Jose, CA]
White LED Head Lamp - A white LED head lamp which can operate with only two
AA batteries. The LEDs are driven in constant current, so that the brightness is
maintained until end of battery life. (added 10/05)
