Single FET Controls 2nd LED Array in Switchmode LED Backlight -  APP1871: Feb03, 2003 A design in which the display is backlit (or frontlit) for extended periods needs an efficient circuit that drives the LEDs with a controlled current, and eliminates the wasted power associated with current-limiting resistors. A switch-mode boost design that regulates current instead of voltage accomplishes this purpose. . . .  [Maxim Integrated]

Single FET controls LED array -  04/12/01 EDN Design Idea   White-LED backlights are gaining acceptance because they offer higher reliability and simpler drive circuitry than backlights based on CCFL (cold-cathode-fluorescent-lamp] and EL (electroluminescent] technology. As a result, white-. . .  [by Len Sherman, Maxim Integrated Products, Sunnyvale, CA]

Single LED dice kit -  Our DICER-S6 has many applications; Play your game with  DICER. Use the single LED-dice kit anywhere you’d like to draw an audience and a smile. No more dice fixing! Use your ESP to guess the next "roll". . . The unique small design will allow you to mount kit almost anywhere. Operates with 9V battery, 12V car battery, four 1. 5V batteries, or via one of our battery simulator kits. . . .  [Kit from Elich Industrial Development, Corp]

Single LED flasher -  Flashing a LED should not require a complex circuit. A reverse biased transistor does the job in a nice way. Circuit "a" flashes the LED twice a second: changing the capacitor and/or the resistor will change the frequency, also the supply voltage. . . 

Single LED Indicates Two Power States -  12/05/96 EDN Design Idea    Uses a single bicolor LED to indicate both power-on and blown-fuse conditions. . .  [by Jim Hagerman, Hagerman Technology, San Diego, CA]

Single-Cell White-LED Driver Uses Improvised Transformer -  02/01/07    EDN Design Idea   Minimal component-count circuit boosts a single cell's voltage to light an LED. . .  [by Jim Grant, Scientific Controls, Orlando, FL]

Single-port pin drives dual LED -  10/13/05  EDN Design Idea    single-line LED driving can be versatile. . .  [by Tom Gay, Dornstadt, Germany]

Solar Charged LED Utility Light -  Tired of always spending money on flashlight batteries only to have them fail just when you need them? Try this simple circuit out. It would make an excellent science fair project. The white LEDs are quite bright, they provide enough light to illuminate a small room at night. The LEDs produce a nicely focused beam. You can read by the light of this device. . . .  [G. Forrest Cook]

Solar Powered Flood Light Using NiMH Cells -  There are many solar powered garden lights available. Most of the devices offered at the home improvement stores have very poor performance. Their batteries are too small, the light launched is weak and the solar panels are undersized. None of the devices I have tested would operate through a typical night . . . [Circuit by Dave Johnson P.E.,  12/20/13]

Solar Powered Infrared 1W Security Camera Illuminator -  Many security cameras are equipped with an array of infrared LEDs to illuminate an area in front of the camera with invisible light for night time surveillance.   However, there are times when a remote area, well away from the camera, needs additional infrared light.   The circuit below uses a modified solar powered path light to bathe a fairly large area with 850nm infrared light . . . [Circuit by Dave Johnson P.E.,  06/22/14]

Solar Powered LED Lamp Circuit -  Here is the simple solution to make an automatic solar powered LED lamp. It automatically switches on two high power White LEDs in the evening and stays on for 6 hours using a 6 volt 4.5Ah rechargeable battery. A 12 volt solar panel is used to charge the battery during day time. The battery is connected to the input line. . .  [Circuit Posted by D Mohankumar]

Solid State Relay that is Bidirectional -  The circuit below can switch up to 4 Amps of current with a peak voltage up to 20v. It is fully isolated using two inexpensive red LEDs. One LED forms a red light source, which illuminates a second red LED. The circuit takes advantage of the 1. 5v . . . [Hobby Circuit designed by David A. Johnson P.E.,  05/01/09]

Sound Triggered Night Light -  A while back, I received a schematic from a guy by the name of Karl. He described a situation he and his wife found themselves in aboard a cruise ship in the Caribbean. They were staying in a room toward the inside of the ship, which did not have any port holes, windows or a balcony . . . [Circuit by David Johnson P.E.,  08/04/13]

Special Lighting  -  experiments with white LEDs. . . 

Speed Adjustable 4 Sequence LEDs -  Our SEQUENCERs4 has many applications; simply power the board and light 4 LEDs start to "move," left to right again and again in sequence! This automatic sequence of blinking lights (LED) can be controlled directly from a front mounted multi-turns trimmer (pot. ) and will draw attention and fun! The unique small design will allow you to mount it almost anywhere. Operate it with 6V, 9V battery, 12V car battery, four 1. 5V batteries, or via one of our battery simulator kits. . .  [Kit from Elich Industrial Development, Corp]

SPI Interface Big 7-Seg LED -  Easy build and use, the general purpose Big LED with SPI serial interfacing. Expandable for multiple digits but still uses only three wires for receiving data from any uC boards. . .  [Wichit Sirichote, designer]

Stealth-mode LED controls itself -  05/25/06  EDN Design Idea    High-efficiency LED doubles as a light detector- Since the LED’s invention more than 30 years ago, its emission efficiency has steadily increased, and, although it may surprise you, the increased conversion efficiency works. . .  [by Howard Myers, Greensboro, NC]

Step-Down Conversion Concept for a PWM-Mode Boost Converter -  TI Application Note . . . 

Strange LED sequencer -  This bizzare but simple PWM circuit fades from LED to LED . . .  [Circuit by Stepan Novotill]

Strange LED Sequencer -  This bizzare but simple PWM circuit fades from LED to LED. This deceptively simple sequencer actually pulse width modulates the LEDs as it fades from one LED to the next. Bulbs will last much longer when driven in this gentle manner; add FETs or transistors to the outputs if you wish to drive bulbs. You can reconfigure the capacitors. . .  [Circuit by Stepan Novotill]

Strip LED Lamp -  This circuit uses strip LEDs to make an automatic white LED lighting source. . . .  [© EFY Enterprises Pvt. Ltd. All rights reserved]

Super Bright 3v Powered LED Flasher -  I have posted several kinds of LED flashers over the years.  This is yet one more flasher, designed to flash any high power LED of any color. It hits the LED with a 25ms 250ma pulse once every 2 seconds.  This works out to an average current about 3ma. It . . . [Circuit by Dave Johnson P.E.,  04/22/09]

Super Simple Flasher -  File contains several designs, please scroll to find this circuit. Here is a simple flasher circuit that uses no resistors! However, it relies on leakage in the base of the PNP germanium transistor and only some will work; be prepared to try a few. If you add a 100k resistor from the base to the collector of the PNP, the circuit will work with most germanium transistors and will work down to 1 VDC! The NPN should be a silicon type. The 100 uF may be replaced with a 22uF in series with a 5k resistor and it would be a good idea to add 39 ohms in series with the base of the NPN (but then the circuit starts to lose its charming simplicity). . . .  [Charles Wenzel (unless otherwise noted)]

Switched Cap Circuits Provide Efficient and Functional White LED Drive (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. . . .  [Texas Instruments App Notes, 30-Apr-13]

Switched Capacitor Circuits Provide Efficient and Functional White-LED Drive -  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. . . .  [Texas Instruments App Notes, 6-Mar-03]

Switching regulator efficiently controls white-LED current -  04/27/06 EDN Design Idea   Circuit has 93% efficiency and beats 64% efficiency of series resistor approach. . .  [by Clayton Grantham]

Synchronous Buck/Boost High Power White LED Driver -   LT3453. . .  [Linear Technology]

Synchronous Step-Up DC/DC Converter for White LED Application -  Application Note LM3500 February 05. . .  [National Semiconductor]

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