|
LED (Light
Emitting Diodes) Circuits Page 13
LED: # A
B C
D - E F - H
I - K L
M - O P- R
S T
U - Z
Last Updated on:
Friday, October 16, 2009 03:43 AM |
| Circuits
Designed by Dave Johnson, P.E. : |
- Universal
LED Flasher
This low power LED flasher circuit draws about 100ua
from any DC power supply ranging from 3 volts to 24 volts. The
1.0Hz 10ms LED pulsed current is held to a constant 10ma.
|
-
Universal 3v LED Flasher
The circuit below will
flash any LED color with fixed current pulses powered by a 3v battery. It uses
a charge pump approach, which routes a constant current pulse through the LED,
regardless of the LED voltage requirement. Using this approach, white and blue LEDs,
which normally require about 3.6v can be flashed with a 3v battery. With the
component values selected, the LED is hit with 15ma current pulses lasting about
10ms every two seconds. This keeps the average current draw from a 3v battery
to about 200uA. The circuit relies on a cheap 74HC14 hex Schmitt trigger
inverter IC. One inverter forms a pulse generating oscillator. Other
inverters are ganged together to increase the drive current. A two transistor
circuit forms a constant sinking current controller.
|
-
Ultra Low Power LED Flasher
The efficiency of some newer LEDs is
amazing. Some of the latest green LEDs can launch blinding light with just one
milliamp of current. I take advantage of one of these newer devices in the
circuit below. The flashing circuit uses a classic multivibrator oscillator, made
from a tiny National Semiconductor’s LMC7215 low power voltage comparator. The
circuit produces a short 10ms pulse every two seconds, drawing power from a 3v
supply. I suggest using a surface mounted green LED from Kingbright.....
|
|
|
- WHITE
LED NIGHT LIGHT
This simple circuit is designed to plug into a standard AC electrical outlet.
It uses four super bright white light emitting diodes (LED) in conjunction with a
capacitor coupled full wave rectifier circuit. The LEDs are mounted in a box and are
angled slightly to bounce the light off of a nearby wall. The light should
last about 10 years. The circuit draws less than one half of one watt of power
and can therefore run continuously. In spite of the low power, the LEDs
provide sufficient illumination for most night light applications. Circuit
component values for both 120vac and 240vac are shown.
|
-
White LED Night Light using a 1W LED
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.....
|
|
|
-
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.....
|
|
|
|
Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
|
|
|
|
Ultra Low Power LED Flasher - The efficiency of some newer LEDs is amazing.
Some of the latest green LEDs can launch blinding light with just one milliamp of
current. I take advantage of one of these newer devices in the circuit below.
The flashing circuit uses a classic multivibrator oscillator, made from a tiny
National Semiconductor’s LMC7215 low power voltage comparator. The circuit
produces a short 10ms pulse every two seconds, drawing power from a 3v supply. I
suggest using a surface mounted green LED from Kingbright..... ….(designed by David A.
Johnson) |
|
Ultra-Bright LED Lamp - (electronic Circuit / Schematic added 10/04) |
|
Ultra-simple Voltage Probe - Detects 1.8 to 220 Volts DC or AC. Minimum
parts counting. (electronic circuit added 06/07/08) |
|
Universal Flasher Circuit - LED flasher with the LM3909 IC (Tony van Roon's
design added 2/06) |
|
Universal LED Flasher - This low power LED flasher circuit draws about 100ua from
any DC power supply ranging from 3 volts to 24 volts. The 1.0Hz 10ms LED pulsed
current is held to a constant 10ma. ….(designed by David A. Johnson) |
|
Universal-3v-LED-Flasher - The circuit below will flash any LED color with
fixed current pulses powered by a 3v battery. It uses a charge pump approach,
which routes a constant current pulse through the LED, regardless of the LED voltage
requirement. Using this approach, white and blue LEDs, which normally require about
3.6v can be flashed with a 3v battery. With the component values selected, ...
….(designed by David A. Johnson) |
|
Use a CFL ballast to drive LEDs - 04/26/07 EDN-Design Ideas: A CFL ballast can
drive a string of as many as 64 LEDs.....(design idea added 04/08) |
|
Use an LED to sense & emit light - 05/14/09 EDN-Design Ideas: LEDs in portable
devices often show power status, battery status, or Bluetooth-connection activity.
LEDs can be major factors in determining battery life because their intensity is
directly proportional to power drain.....(design idea added 08/09) |
|
Using the TPS61040 in High Voltage Applications - TI Application Note (added
2/06) |
|
Valentine Heart - 18 LEDs flash at three different rates and you can use these to
create an eye-catching Valentine Heart for that special person! A template for the
heart shape can be downloaded. The circuit is kept simple (and low cost) by using the
4060B IC which is a counter and oscillator (clock) in one package.....Designed by John
Hewes (circuit added 06/07/08) |
|
Voltage to Frequency Converter + 1uS LED Pulse Driver - This circuit receives the
signal from the above amplifier and launches powerful 1uS infrared light pulses from a
low cost LED that are frequency modulated by the audio information. The 10KHz center
frequency of the pulse stream is low enough so a standard infrared LED can emit ten
times more light than conventional long pulse techniques. The circuit is described in
more detail in the transmitter section of my Handbook of Optical Through the Air
Communications. ….(designed by David A. Johnson) |
|
Voltage-to-current converter drives white LEDs - 06/27/02 EDN-Design Ideas: You
sometimes need to drive a white LED from one 1.5V battery. Unfortunately, the forward
voltage of a white LED is 3 to 4V. So, you would need a dc/dc converter to drive the
LED from one battery. Using the simple circuit in Figure 1, you can drive one white
LED or two series-connected green LEDs, using only a few components.....(design idea
added 9/03) |
|
|
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 & Keypad - 11/13/03 EDN-Design Ideas: 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.....(design idea added 1/05) |
|
White LED Driver in Tiny SC70 Package Achieves 84% Efficiency - Linear Technology
Magazine Design Ideas August 2002 (app note added 02/05) |
|
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 added 02/05) |
|
White LED driver operates down to 1.2V supply voltage - 09/03/07 EDN-Design Ideas:
This circuit beats commercially available LED drivers, which bottom out at 2.5V input
voltage, by operating at voltages as low as 1V.....(design idea added 09/08) |
|
White LED Driver Provides 64 Step Logarithmic Dimming - 06/10/04 EDN-Design Ideas:
The circuit in this Design Idea 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.....(design idea added 1/05) |
|
White LED Driver Touts High Efficiency - 06/12/03 EDN-Design Ideas: 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,.....(design idea added
7/03) |
|
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 Life Tester - This simple circuit is designed to plug into a standard AC
electrical outlet. It uses four super bright white light emitting diodes (LED)
in conjunction with a capacitor coupled full wave rectifier circuit. The LEDs are
mounted in a box and are angled slightly to bounce the light off of a nearby wall.
The light should last about 10 years. The circuit draws less than one half of
one watt of power and can therefore run continuously. In spite of the low power,
the LEDs provide sufficient illumination for most night light applications.
Circuit component values for both 120vac and 240vac are shown. ….(designed by David A.
Johnson) |
|
White LED Night Light using a 1W LED - 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 - 01/10/08 EDN-Design Ideas:
A piezoelectric ceramic buzzer powers a white LED from a single cell.....(design idea
added 9/08) |
|
White LED Step-Up Converter in SC70 & ThinSOT - Linear Technology LT1937 (app note
added 02/05) |
|
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..... ….(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) |
|
|
| |
|
LED: #
A B
C D - E
F - H I - K L
M - O P- R
S T
U - Z |
|
|
