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20mA LED Ballast - (corrected text) 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 __ Designed by Andrew R. Morris 24V DC Powered Beeper with 4 Separate Inputs - 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. This hobby circuit below is one method to efficiently power a cluster of 7 white LEDs from 24vac. . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2009
30W White LED Automotive Headlamp Driver with Thermal Derating - The LT3756, LT3756-1 and LT3756-2 are DC/DC controllers designed to operate as a constant-current source for driving high current LEDs. They drive a low side external N-channel power MOSFET from an internal regulated 7.15V supply. The fixed frequency, current-mode architecture results in stable operation over a wide range of __ Linear Technology/Analog Devices App Note,
3-Channel White-LED Driver Uses Simple Circuit Step-Down DC/DC Converter - 09/13/12 EDN-Design Ideas Drive multiple LEDs with current mirrors from a single step-down converter. Design by Nora Jacalan Esteves, Technor Semiconductor LLC, Pleasanton, CA
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 3.3 v. White and blue LEDs normally require over 3v, so the circuit below uses a charge pump scheme to deliver a constant LED light intensity. . . Circuit by David Johnson P.E.-August, 2010
50W White LED Automotive Headlamp Driver - The LT3755, LT3755-1 and LT3755-2 are DC/DC controllers designed to operate as a constant-current source for driving high current LEDs. They drive a low side external N-channel power MOSFET from an internal regulated 7.15V supply. The fixed frequency, current mode architecture results in stable operation over a wide range of supply and output voltages. A ground referenced voltage FB pin serves as the input for several LED protection features, and also makes it possible for the converter to operate as a constant-voltage source. A frequency adjust pin allows the user to program the frequency from 100kHz to 1MHz to optimize efficiency, performance or external component size.
__ Linear Technology/Analog Devices App Note, Jul 20th 2010
7 by 10 LED Moving Sign - This sign uses two LED arrays to form a 7 X 10 matrix. It produces moving messages or animations stored in an EPROM. It uses no microprocessor. As in most electric signs, the LEDs are matrixed, and strobed very quickly. __ Designed by Bob Blick
7 Component Regulated LED Lamp - This is a minimal parts lamp made with four white LEDs. It features regulated light output from 10V to around 20V and works well as a flashlight. __ Designed by G. Forrest Cook
AC Line Powered LED Strings - This shows 4 different ways to string white LEDs that are powered by a 120vac or 240vac power line. This hobby circuit was designed by Ken Schultz. __ Designed by Ken Schultz, drawn Dave Johnson 12.18.2004
Atmel AVR Tiny13V for driving a white LED - LED headlamp projects: Tiny13V microcontroller as step up (boost) or step down (buck) voltage converter for driving a white or high power LED. (pdf file) Desgin equations and source code included. __ Designed by Steven Weber, KD1JV
Bidirectional Solid State Relay - 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. . . Circuit by David Johnson P.E.-May, 2009
Buck IC Boosts Battery Voltage for White LED - 04/24/03 EDN-Design Ideas 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 by Robert Kollman, Texas Instruments, Dallas, TX
Buck regulator controls white LED with optical feedback - 10/25/07 EDN-Video Design IdeasBy using optical feedback, you can stabilize the output level of a high-intensity LED Design by Dhananjay V Gadre, Netaji Subhas Institute of Technology, New Delhi, India
Build a Bright-White LED Torch - You get high brightness, a cool white light and very low battery drain. And you'll never have to replace the bulb again.__ SiliconChip
Circuit Delivers Dimming Control for White-LED Driver - 10/28/04 EDN-Design Ideas The demand for power in color cell-phone handsets is constantly increasing. New applications steadily emerge, making it imperative to reduce power consumption in the design. Examination of usage data shows thatthan 50% of the power Design by Wallace Ly, National Semiconductor, Santa Clara, CA
Circuit drives latching relays - 02/01/96 EDN-Design Ideas Figure 1 shows a low-parts-count circuit that can drive one- or two-coil latching relays. Latching relays are useful in sensitive analog designs. The 74ACT174 hex flip-flop has ample capability to drive the Aromat TQ2E series of latching relays. Both windings for the TQ2E-L2-5V two-coil relay are on the same magnetic element, so the windings' fields add. You Design by Roy McCammon, 3M Austin, TX
Circuit drives mixed types & quantities of LEDs - 10/03/02 EDN-Design Ideas Portable systems often use LEDs of different colors and in varying quantities of each color. Some examples are white for the display backlight, green for keypad illumination, and red for power. Typically, the LEDs derive power from at least two power supplies one for "standard" LEDs (red and green] and one for white LEDs Design by Mark Pearson, Maxim Integrated Products, Sunnyvale, CA
Circuit Drives White LEDs - 11/23/00 EDN-Design Ideas Newly available white LEDs are replacing CCFLs (cold-cathode fluorescent lamps] in handheld applications using a back-lit LCD. These applications include PDAs (personal digital assistants], digital cameras, and cellular telephones, Design by Eddy Wells, Texas Instruments
Constant current, constant voltage converter drives white LEDs - 09/02/04 EDN-Design Ideas LEDs usually take their drive from a constant dc-current source to maintain constant luminescence. Most DC/DC converters, however, deliver a constant voltage by comparing a feedback voltage to an internal reference via an internal error amplifier. The easiest way to turn a simple DC/DC converter into a constant-current source is to use a sense resistor to convert the output current to a voltage Design by Keith Szolusha, Linear Technology Corp, Milpitas, CA
Control Variable LED Intensity - The circuit below uses power from four rechargeable AA NiMH
cells to drive 3 white LEDs. A potentiometer varies the duty cycle of a pulse width modulator circuit to vary the intensity of the LEDs from 0% to 100%. The beauty of the circuit is that when the . . . Hobby Circuit designed by Dave Johnson P.E.-September, 2009
DC/DC Converter Drives LumiLEDs White LEDs from a Variety of Power Sources - DN340 Design Notes__ Linear Technology/Analog Devices
Deliver Dimming Control for White-LED Driver - 10/28/04 EDN-Design Ideas The demand for power in color cell-phone handsets is constantly increasing. New applications steadily emerge, making it imperative to reduce power consumption in the design. Examination of usage data shows thatthan 50% of the power Design by Wallace Ly, National Semiconductor, Santa Clara, CA
Drive latching relays - 02/01/96 EDN-Design Ideas Figure 1 shows a low-parts-count circuit that can drive one- or two-coil latching relays. Latching relays are useful in sensitive analog designs. The 74ACT174 hex flip-flop has ample capability to drive the Aromat TQ2E series of latching relays. Both windings for the TQ2E-L2-5V two-coil relay are on the same magnetic element, so the windings' fields add. You Design by Roy McCammon, 3M Austin, TX
Drive mixed types & quantities of LEDs - 10/03/02 EDN-Design Ideas Portable systems often use LEDs of different colors and in varying quantities of each color. Some examples are white for the display backlight, green for keypad illumination, and red for power. Typically, the LEDs derive power from at least two power supplies one for "standard" LEDs (red and green] and one for white LEDs Design by Mark Pearson, Maxim Integrated Products, Sunnyvale, CA
Drive White LEDs - 11/23/00 EDN-Design Ideas Newly available white LEDs are replacing CCFLs (cold-cathode fluorescent lamps] in handheld applications using a back-lit LCD. These applications include PDAs (personal digital assistants], digital cameras, and cellular telephones, Design by Eddy Wells, Texas Instruments
Driving White LEDs - The 555 is capable of sinking and sourcing up to 200mA, but it gets very hot when doing this on a 12v supply. The following circuit shows the maximum number of white LEDs that can be realistically driven from a 555 and we have limited the total current to about 130mA as each LED is designed to pass about 17mA to 22mA maximum. A white LED drops a characteristic 3.2v to 3.6v and this means only 3 LEDs can be placed in series. __ 555-Timer
Dual Full Function White LED Step-Up Converter with Built-In Schottky Diodes - LT3466__ Linear Technology/Analog Devices
Dual White LED Driver Features Integrated Switches & Schottky Diodes in 3mm × 3mm Dfn Package - DN1010 Design Notes__ Linear Technology/Analog Devices |
