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White LED
(White Light Emitting Diodes) Circuits
White LEDs: #-B
C - K L - P
Q - V W - Z
LED Circuits
Last Updated on:
Monday, October 03, 2011 06:08 PM |
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Circuits Designed
by Dave Johnson, P.E. : |
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1W 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.....
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24VAC Powered White LEDs - 24vac is a popular voltage. It is
often used in low voltage lighting systems and industrial controls. It is
much less dangerous than 120vac/240vac line voltages. The circuit below is
one method to efficiently power a cluster of 7 white LEDs from 24vac. It
uses a classic bridge rectifier and filter capacitor to convert the AC to
DC.....
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3V BATTERY POWERED WHITE LED
DRIVER
The circuit below will drive any LED color, including white LEDs, using a DC
power supply ranging from 2v to 3.3v. White and blue LEDs normally require over
3v, so the circuit below uses a charge pump scheme to deliver a constant LED
light intensity from a voltage less than 3v. The LED is rapidly pulsed with 3ma
peak current, which remains fairly constant, even as the battery voltage
changes. The circuit is designed only for low LED current applications. A
common CR2032 lithium coin battery should run the light for two days. A pair of
2.5 amp-hour AA NiMH cells should operate the circuit for nearly a month.
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Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
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1.5V battery powers white LED driver - 30-Sep-04 Issue of EDN
Although white LEDs are common in a variety of lighting applications,
their 3 to 4V forward-voltage drop makes low-voltage applications
challenging. Charge pumps and other ICs are available for driving white
LEDs, but they generally don't work with the low supply voltage of 1.5V in
single-cell-battery applications.....PDF has many circuits, please scroll
to find this one..... [Design Idea by Steve Caldwell, Maxim Integrated
Products, Chandler, AZ] |
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18 LED dimmable LED lamp - bright LED cluster [G. Forrest Cook] |
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1W 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...... [Designed by David A. Johnson] |
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20ma LED Ballast - I use this circuit for general use to power
white LEDs, like a headset light I use on my desk and a keyboard light for
my computer. I built it into a tiny Radio Shack project box (270-288),
which y no longer sell. I put heat-shrink tubing around.....Designed by
Andrew R. Morris (added 6/06) |
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24VAC Powered White LEDs - 24vac is a popular voltage. It is often
used in low voltage lighting systems and industrial controls. It is much less
dangerous than 120vac/240vac line voltages. The circuit below is one method to
efficiently power a cluster of 7 white LEDs from 24vac. It uses a classic bridge
rectifier and filter capacitor to convert the AC to DC..... [Designed by David A.
Johnson] |
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3V BATTERY POWERED WHITE LED DRIVER
- The circuit
below will drive any LED color, including white LEDs, using a DC power supply ranging
from 2v to 3.3v. White and blue LEDs normally require over 3v, so the circuit below
uses a charge pump scheme to deliver a constant LED light intensity from a voltage
less than 3v. The LED is rapidly pulsed with 3ma peak current, which remains fairly
constant, even as the battery voltage changes. The circuit is designed only for low
LED current applications. A common CR2032 lithium coin battery should run the light
for two days. A pair of 2.5 amp-hour AA NiMH cells should operate the circuit for
nearly a month.....[Designed by Dave Johnson, P.E.] |
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AN-1250: Inductive Based Switching Regulator Circuits Provide High Efficiency White
LED Drives - National Semiconductor Application Note (app note added
2/06) |
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AN-1251: Switched Capacitor Circuits Provide Efficient & Functional White LED Drive
- National Semiconductor Application Note (app note added 2/06)
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AN-1324: LM3570: Low Noise White LED Driver System - National Semiconductor
Application Note (app note added 2/06) |
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AN-1362: LM27961-Dual-Display White LED Driver with 3/2x Switched Capacitor Boost
- National Semiconductor Application Note (app note added 2/06)
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AN33 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) |
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AN948: Efficiently Powering Nine White LEDs with the MCP1650 - Microchip
Application Note Published 3-Aug-04 (app note added 2/06) |
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Astable multivibrator (blinkie) - A pulse generator, or astable, circuit can
be made using four resistors, two capacitors, two LEDs and two transistors. 'Blinkie'
uses these components to form a face, with the flashing LEDs representing the eyes.
(electronic design added 08/08/08 |
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Buck IC boosts battery-voltage for white LED - 24-Apr-03 Issue of EDN
White-light LEDs are finding their way into many markets that incandescent bulbs once
served. Flashlights are among the newer applications in which reliability, ruggedness,
and ability to control the power draw of the LEDs make these devices attractive. With
incandescent bulbs, the power management for the device is a simple on-off switch.....
[Design Idea by Robert Kollman, Texas Instruments, Dallas, TX] |
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Buck/Boost Charge Pump Regulator Powers White LEDs from a Wide 1.6 Volt to 5.5 Volt
Input - Maxim Application Note #1021 (app note added 5/08) |
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