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Light Emitting Diodes (LED) Circuits
LEDs:   #'s - B     C - G      H - L       M - P       Q - T     U - Z 
 

Last Updated: October 24, 2017 02:55 PM

Circuits Designed by Dave Johnson, P.E. :

Line Powered High Intensity LED FlasherThere are times when you would like to generate an intensely bright flash of light using electrical power from the AC line.  The circuit below can drive a one to three watt power LED with about 350ma of peak current.  Since the circuit drives the LED with . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2008

Line Powered White LED ArrayThere has been a lot of excitement lately in the lighting industry.  Some companies are beginning to manufacture general lighting fixtures, which replace incandescent and fluorescent lamps, using LED lights.  When proper heat management is designed. . . Circuit by David Johnson P.E.-February, 2010

Line Status Indicator for 1 Telephone LineThis circuit monitors one phone line . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Low Current Flashing LED Power Indicator This circuit flashes a power indicator LED to keep the average current low . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Low Pass Filter, 3Khz, with an Audio AmpThis circuit uses a switched capacitor filter IC from National Semiconductor to filter signals with frequencies higher than the 3KHz needed for voice audio.  The schematic includes an audio amplifier that is designed to drive a standard audio head phone . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Low Power LED FlasherJudging from the numerous references I have received, this electronic circuit, hobby circuit seems to be rather popular.  Many published circuits which flash LEDs need 3 or more volts.  This electronic circuit uses only a single inexpensive C-MOS IC and . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Low Power Sequential Flasher using 10 LEDsA while back I posted a flasher circuit which flashed 10 LEDs sequentially.  That circuit was powered by four AA alkaline cells.  The circuit below operates much the same way but has been modified to run from a single 3v CR2032 lithium coin cell . . . Hobby Circuit designed by Dave Johnson P.E.-April, 2011

Low Power Universal LED FlasherThis 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. . . Circuit by David A. Johnson P.E.-July, 2006

 

 

 


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Light a white LED from half a cell -  12-Jun-03 EDN-Design Ideas Whether you use them as indicators or to provide illumination, LEDs are hard to beat in efficiency, reliability, and cost.  White LEDs are rapidly gaining popularity as sources of illumination, as in LCD backlights, but with forward voltages typically ranging from 3 to 5V, operating them from a single cell presents obvious difficulties __ Circuit Design by Anthony Smith, Scitech, Biddenham, Bedfordshire, UK

Light an LED without wasting energy -  The circuit in Figure 1 can minimize this waste by using an inductor and an oscillating circuit to control the current through the LED—energy that would otherwise go to waste.  Inductor L1 stores power and channels it back into the LED.    __ Circuit Design by Raju R Baddi, Tata Institute of Fundamental Research, Maharashtra, India; Edited by Martin Rowe and Fran GranvilleApril 21, 2011

Light Collar Helps You Find Your Pet In the Dark -  10/07/10 EDN-Design Ideas Keep your pet from getting lost in the dark.  If you have a pet, you know how difficult it is to find him or her in the dark, especially when your pet has dark fur.  The circuit in Figure 1 lets you build a collar with LEDs that helps you find your pet.   The heart of the circuit is the ZXLD381FHTA LED driver from Zetex.  Two 1.2 or 1.5V cells power the LED driver, providing the current pulses to illuminate six to eight 20-mA LEDs of any color series.  The ZXLD381 dc/dc boost converter’s primary application is in LED drivers.   __ Circuit Design by Vladimir Oleynik, Moscow, Russia

Light Pollution Meter -  LED brightness control circuit and a millimeter to compare light levels to LED level __ Designed by Avery Davis

Lighthouse LED Flasher -  This was originally designed for a model in a HO train set.  It simulates the behavior of the light from a lighthouse.  The LED intensity gradually increases, then flashes with a bright light and finally decreases slowly in intensity. . . Circuit by Dave Johnson P.E.-July, 2006

Lightning Lights -  Schematic + Info + pictures10 LEDs light up from top to bottom, following the lightning bolt’s path.  The LEDs turn off back up into the cloud.  The display looks best with backlighting.  The bolt seems to glow in the dark. __ Designed by Lennie Zink

Li-Ion to Six White LEDs & OLED/LCD Bias -  The LT3498 can provide both the positive bias voltage required for OLED or CCD bias as well as drive multiple white LEDs for display backlighting__ Linear Technology/Analog Devices App Note, Mar 24th 2010

Li-Ion to Two White LEDs & OLED/LCD Bias -  The LT3498 can provide both the positive bias voltage required for OLED or CCD bias as well as drive multiple white LEDs for display backlighting__ Linear Technology/Analog Devices App Note, Mar 24th 2010

Line Powered High Intensity LED Flasher -  There are times when you would like to generate an intensely bright flash of light using electrical power from the AC line.  The circuit below can drive a one to three watt power LED with about 350ma of peak current.  Since the circuit drives the LED with . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2008

Line Powered White LED Array -  There has been a lot of excitement lately in the lighting industry.  Some companies are beginning to manufacture general lighting fixtures, which replace incandescent and fluorescent lamps, using LED lights.  When proper heat management is designed. . . Circuit by David Johnson P.E.-February, 2010

Line Powered White LEDs -  The LED circuit above is an example of using 25 white LEDs in series connected to the 120VAC line.  It can be modified for more or less LEDs by changing the R value.  The exact resistance value will depend on the particular LEDs used.  In operation, a DC voltage of around 170 is produced from the bridge rectifier and 50uF capacitor.  The capacitor value is not critical __ Designed by Bill Bowden

Line Status Indicator for 1 Telephone Line -  This circuit monitors one phone line . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Linear & Switcher LED Supplies Combine, Overcome Disadvantages Of Each Topology -  01/08/2013   To control their brightness, LEDs need a constant current; this can be done with a resistor placed in series with the LED string.  Both the LED-string voltage and the supply voltage can vary, so a dedicated LED driver is a must to guarantee the current accuracy.  Two solutions—each with advantages and disadvantages—are widely used: a linear constant-current LED driver or a step-down switching converter.   __ Circuit Design by Fabien Franc, On Semiconductor, Phoenix

Linear Constant Current LED Lamp Dimmer -  This circuits drives 24 white light LEDs with an adjustable constant current

Linear Supply for Luxeon 1W Star LEDs -  Simple circuit lets you run one or more Luxeon 1W Star LEDs from a 12V DC supply.  It uses low-cost parts and allows for dimming as well.__ SiliconChip

Linear-brightness controller for LEDs has 64 taps -  03/15/07  EDN-Design Ideas Digital potentiometer controls the brightness of LEDs __ Circuit Design by Ahmad Ayar, Maxim Integrated Products, Sunnyvale, CA

Line-powered driver lights up high-power LEDs -  06/08/06  EDN-Design Ideas LED array reduces power and maintenance expenses __ Circuit Design by Aaron Lager, Masterwork Electronics, Rohnert Park, CA

Little bike light using LEDs -  No circuit description, schematic only__ CdS Electronic

LM143 Monolithic High Voltage Operational Amplifier Applications -  LED lighting designers are challenged with meeting their efficiency and reliability goals faster in advanced LED lighting designs.  LED lighting customers seeking the latest in innovative and affordable LED lighting solutions can benefit from TI's broad product portfolio of LED drivers, AC/DC, DC/DC, power management devices, wireless and wired interface control and embedded processors.  LED designers have the option of not only controlling the power stage, but regulating LED currents as well, eliminating the need for multiple components and reducing system cost.   __ Designed by Texas Instruments App Notes, 2-May-04

LM2755 Charge Pump LED Controller with I2C Compatible Interface in SMD (Rev. A) -  LED lighting designers are challenged with meeting their efficiency and reliability goals faster in advanced LED lighting designs.  LED lighting customers seeking the latest in innovative and affordable LED lighting solutions can benefit from TI's broad product portfolio of LED drivers, AC/DC, DC/DC, power management devices, wireless and wired interface control and embedded processors.  LED designers have the option of not only controlling the power stage, but regulating LED currents as well, eliminating the need for multiple components and reducing system cost.   __ Designed by Texas Instruments App Notes, 30-Apr-13

LM2756 Multi-Display Inductorless LED Driver w/32 Exp Dimming Steps in SMD (Rev. A) -  LED lighting designers are challenged with meeting their efficiency and reliability goals faster in advanced LED lighting designs.  LED lighting customers seeking the latest in innovative and affordable LED lighting solutions can benefit from TI's broad product portfolio of LED drivers, AC/DC, DC/DC, power management devices, wireless and wired interface control and embedded processors.  LED designers have the option of not only controlling the power stage, but regulating LED currents as well, eliminating the need for multiple components and reducing system cost.   __ Designed by Texas Instruments App Notes, 30-Apr-13

LM27961-Dual-Display White LED Drvr w/3/2x Switched Cap Boost (Rev. A) -  LED lighting designers are challenged with meeting their efficiency and reliability goals faster in advanced LED lighting designs.  LED lighting customers seeking the latest in innovative and affordable LED lighting solutions can benefit from TI's broad product portfolio of LED drivers, AC/DC, DC/DC, power management devices, wireless and wired interface control and embedded processors.  LED designers have the option of not only controlling the power stage, but regulating LED currents as well, eliminating the need for multiple components and reducing system cost.   __ Designed by Texas Instruments App Notes, 30-Apr-13

LM27965 Dual Display White LED Driver w/I2C Compatible Brightness Control (Rev. B) -  LED lighting designers are challenged with meeting their efficiency and reliability goals faster in advanced LED lighting designs.  LED lighting customers seeking the latest in innovative and affordable LED lighting solutions can benefit from TI's broad product portfolio of LED drivers, AC/DC, DC/DC, power management devices, wireless and wired interface control and embedded processors.  LED designers have the option of not only controlling the power stage, but regulating LED currents as well, eliminating the need for multiple components and reducing system cost.   __ Designed by Texas Instruments App Notes, 30-Apr-13

LM3553 1.2A Dual Flash LED Driver System with I2C Compatible Interface (Rev. B) -  LED lighting designers are challenged with meeting their efficiency and reliability goals faster in advanced LED lighting designs.  LED lighting customers seeking the latest in innovative and affordable LED lighting solutions can benefit from TI's broad product portfolio of LED drivers, AC/DC, DC/DC, power management devices, wireless and wired interface control and embedded processors.  LED designers have the option of not only controlling the power stage, but regulating LED currents as well, eliminating the need for multiple components and reducing system cost.   __ Designed by Texas Instruments App Notes, 30-Apr-13

LM3909 LED flasher -  LED flasher with the LM3909 IC and runs from1.5-Volt battery.   __ Designed by Tony van Roon  VA3AVR

LM3916 Dot/Bar Display Driver -  The LM3916 is a monolithic integrated circuit that 2 senses analog voltage levels and drives ten LEDs, LCDs, or Vacuum Fluorescents LCDs or vacuum fluorescent displays, providing an electronic version of the popular VU meter.  One pin by User changes the display from a bar graph to a moving dot display __ Designed by SNVS762B – JANUARY 2000 – REVISED MARCH 2013

Logic Probe uses Bicolor LED -  03/13/98 EDN Ideas -  (File has several circuits, scroll to this one) A project posed the challenge of replacing existing analog potentiometers  (used to set brightness and contrast levels]in video monitors with digitally controlled potentiometers.  The different brands and models of monitors presented widely varying voltages across the potentiometers.  The design.    __ Circuit Design by Mark Shill, Burr-Brown Corp, Tucson, AZ

Low Current Flashing LED Power Indicator This circuit flashes a power indicator LED to keep the average current low . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Low Pass Filter, 3Khz, with an Audio Amp -  This circuit uses a switched capacitor filter IC from National Semiconductor to filter signals with frequencies higher than the 3KHz needed for voice audio.  The schematic includes an audio amplifier that is designed to drive a standard audio head phone . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Low Power Blink LED -  Schematic only, no circuit description __ Designed by Rob Crockett

Low Power LED Flasher -  Judging from the numerous references I have received, this electronic circuit, hobby circuit seems to be rather popular.  Many published circuits which flash LEDs need 3 or more volts.  This electronic circuit uses only a single inexpensive C-MOS IC and . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Low Power LED Flasher -  It doesn't get much simpler than this circuit.  Four components counting the battery! How can an LED be illuminated by a 1.5V circuit, when the forward voltage of an LED is about 2V? The LM3909 uses the 100uF capacitor as a charge reservoir, building up a voltage of about 2V before discharging the cap through the LED.   __ Designed by billd @ reprise.com

Low Power LED Voltmeter -  This is a low power voltmeter circuit that can be used with alternative energy systems that run on 12 and 24 volt batteries.  The voltmeter is an expanded scale type that indicates small voltage steps over the 10 to 16 volt range for 12 volt batteries and over the 22 to 32 volt __ Designed by G. Forrest Cook

Low Power Sequential Flasher using 10 LEDs -  A while back I posted a flasher circuit which flashed 10 LEDs sequentially.  That circuit was powered by four AA alkaline cells.  The circuit below operates much the same way but has been modified to run from a single 3v CR2032 lithium coin cell . . . Hobby Circuit designed by Dave Johnson P.E.-April, 2011

Low Power 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. . . Circuit by David A. Johnson P.E.-July, 2006

Low-Component-Count Logic Probe Works with TTL & CMOS Logic -  04/07/11  EDN-Design Ideas LED's indicate logic levels.  The circuit in Figure 1 uses the LM358 dual op amp running as a comparator, plus a few other inexpensive components, to make a TTL  (transistor-transistor-logic) /CMOS -logic probe.  The circuit gets its power from the circuit under test, which lets it work with TTL or CMOS logic.  The IC1A and IC1B op amps come in an LM358 package.  Switch S1 selects the TTL or the CMOS mode of operation.  The green LED shows logic low, and the red LED shows logic high.   __ Circuit Design by Aruna Rubasinghe

Low-Cost Dual Digital Dice -  This simple dual digital dice is based on three low-cost ICs, a few transistors and a handful of LEDs.  IC1a & IC1b operate as an oscillator with a frequency of about 4kHz and this clocks IC2.  The frequency of oscillation is not criticalit simply needs to be high enough to prevent cheating.  IC2 and IC3 are 4516 binary counters, configured to count in binary from 1-6.__ Learning Electronics

Low-duty-cycle LED flasher keeps power draw at 4 mW -  EDN-Design Ideas 01/23/13    Battery-operated equipment often will benefit from a power-on indicator. The indicator, however, can waste significant power.In situations where a low-duty-cycle blinking indicator provides an adequate indication of the power being turned on, the simple circuit described here should prove useful.    __ Circuit Design by Marian Stofka

Low-Power, long life LED flashlight -  Scouring the Internet for information on LEDs, I accidentally stumbled upon a PDF detailing a flashlight made from PVC.  For the torch, he biases ultra-bright LEDs with ballast resistors as described in my LED lighting guide.  This is a simple solution, but a with a slightly more complicated circuit we can extend battery life by over ten times!

LT3465-1.2MHz White LED Step-Up Converters with Built-In Schottky in ThinSOT -  LT3465 Switching Regulator__ Linear Technology/Analog Devices

LT3518 Full-Featured 45V, 2.3A Switch Current LED Driver-Video Product Brief -  The LT3518 is a current mode DC/DC converter with an internal 2.3A, 45V switch specifically designed to drive LEDs.  The LT3518 operates as a LED driver in boost, buck and buck-boost modes.  It combines a traditional voltage loop and a unique current loop to operate as a constant-current source or constant-voltage source.  Programmable __ Linear Technology/Analog Devices App Note, Steve Knoth-Senior Product Marketing Engineer Aug 25th 2010

LT3791 Buck-Boost Controller Drives High-Power LEDs, Charges High-Voltage Batteries -  08/29/13  EDN-Design Notes The LT®3791 is a 4-switch synchronous buck-boost DC/DC converter that regulates both constant-current and constant-voltage at up to 98.5% efficiency with a single inductor.  It can deliver hundreds of watts and features a 60V input and output rating, making it ideal for driving high power LED strings and charging high voltage batteries when both step-up and step-down conversion is needed.  It can also be used as a constant voltage buck-boost regulator with current limiting and monitoring for both input and output.   __ Circuit Design by Keith Szolusha

   <<<         This is last page of HL

LEDs:   #'s - B     C - G      H - L       M - P       Q - T     U - Z 

 


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