|
White LED Circuits - (electronic circuit added 4/05) |
|
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.... [Design Idea
by Fabien Franc, Catalyst Semiconductor, Sunnyvale, CA] |
|
White LED Driver in Tiny SC70 Package Achieves 84% Efficiency - Linear
Technology Magazine Design Ideas August 2002.....[App Note] |
|
White LED Driver in Tiny SC70 Package Delivers High Efficiency & Uniform LED
Brightness - DN315 Design Notes (Linear Technology) (app note added
1/06) |
|
White LED Driver Minimizes Space Maximizes Efficiency & Flexibility - Linear
Technology Magazine Design Feature December 2003.....[App Note] |
|
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) |
|
White LED inductorless drive from 1.5V & 3V - The operating voltage of white
LEDs coupled with my emotional need for low cost for a given function, motivates me to
make LED drivers suitable for battery operated lanterns that can run from a small
number of cells. White and Ultraviolet LEDs available at the time of this writing,
require higher voltages than colored LED's.....(schematic / circuit added 6/07)
|
|
White LED is Powered by One NiMH Cell - There are a lot of white LED driver
circuits floating around. A popular circuit called the “Joule Thief” can
drive one white LED from a single 1.2v or 1.5v battery cell. Most of these
circuits use one or two transistors to form a voltage boost circuit. Yes, they
those circuit do drive a LED but they are not very efficient and they don’t do a good
job of controlling the current to the LED....[Designed by David A. Johnson] |
|
White LED Life Tester - There are lots of white LEDs for sale these days.
Many eBay and electronic component surplus sales claim to sell some very bright
devices. Over the years I have purchased some of them to experiment with.
I also have purchased some products, which contain white LEDs. A major
disappointment for me was some LED night lights I bought from Costco...[Hobby Corner
Circuit by Dave Johnson] |
|
White LED Night Light - As many of you know, I have a pet peeve with poorly
made LED night lights. Often, the light from the LED quickly fades, so within
months, the light is useless. I have posted several versions of modified night
lights using higher quality components. This circuit is yet another version, which
produces much more light than those other designs. The circuit brings together two
high power white LEDs made by Cree with a compact AC to DC power supply from Bias
Power..... [Designed by David A. Johnson] |
|
White LED Power Supply Design Techniques - TI Application Note (added
2/06) |
|
White LED shines from piezoelectric oscillator supply - 10-Jan-08 Issue of
EDN A piezoelectric ceramic buzzer powers a white LED from a single cell.....
[Design Idea by TA Babu, Chennai, India] |
|
White LED Step-Up Converter in SC70 & ThinSOT - Linear Technology
LT1937.....[App Note] |
|
White LED Stroboscope With Constant Duty Cycle & Constant Current Drive -
Finally, white LED's are bright enough to use in a practical stroboscope. This
circuit can operate as a bench-top stroboscope that, in conjunction with an
oscilloscope or frequency meter and bench top power supply can accurately measure
rotational speeds, or it can be operated hand-held from a single 9V
battery,.....(schematic / circuit added 6/07) |
|
White Light LED Driver with Gradual Dimming - TI Application Note
(added 2/06) |
|
Wide Input Range 1a LED Driver Powers High Brightness LEDs with Automotive & 12 VAC
Supplies - DN1012 Design Notes (Linear Technology) (app note
added 1/06) |
|
Wig/Wag LED Flasher - This simple circuit will flash two LEDs in an
alternating fashion. …. [Designed by David A. Johnson] |
|
Wireless LED Driver - The circuit solves this problem by sending power to
the LED through the plastic, using a magnetic coupling technique. The circuit below
can route power through plastic enclosures as thick as ¼ inch. The circuit will
not work through metal boxes..... [Hobby Corner Circuit by Dave Johnson] |
Wireless LED Flasher
There are times when you would like to flash a LED through a thick plastic case
without wires. The circuit below performs this feat. It can be powered
from a supply ranging from 3v to 6v. It draws about 300ua of average current at 5v. It
uses a low power op amp as a pulse generator. A negative going pulse from that
generator gates a power oscillator on for about 20ma. That oscillator is
connected to a series resonant circuit, which drives a small coil....[Designed by
David A. Johnson] |
|
ZXSC100 Single cell DC-DC converter LED driving applications - Zetec
Semiconductors Applications Notes ZXSC100 single cell DC-DC converter offers an
ideal solution to driving white LEDs in flashlights, enabling operation from a single
NiCd or NiMH cell. (app note added 6/06) |
|
|
