Circuits & Schematics - Light - 5

Dan Awtrey Electronic Design By pairing a visible-light LED (VLED) with a depletion-mode MOSFET, you can create an efficient, controllable current-source driver. High-brightness visible-light LEDs (VLEDs) require a constant-current source. This ...

Neda Shahi EDN Recent advances in operating efficiency have expanded the use of LEDs from one of mere indicators to becoming driving forces in electronic lighting. Increased reliability and ruggedness (versus other lighting technologies) gives the ...

Marián Štofka EDN The human eye can see any color as a mixture of blue, red, and green. The circuit in Figure 1 produces all three colors through an Broadcom ASMT-YTB0 tricolor LED. You can produce a wide range of colors by varying ...

Although white LEDs are common in a variety of lighting applications, their 3 to 4 V 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 ...

Jianwen Shao EDN Due to their light output and long life, high-brightness LEDs are well-suited for use in flashlights. Typically, the LEDs are driven with a constant current. So when the battery voltage drops, the flashlight just stops working. In ...

Dhananjay Gadre EDN There is much interest in LED-based lighting due to the availability of high-power, high-efficiency white and other-color LEDs (Reference 1). Because an LED is a current-controlled device, typical control circuits regulate the ...

Hua (Walker) Bai Electronic Design LED applications are booming: backlighting for LCD TVs, projectors, and computer displays, camera flashes, and vehicle brake lights and taillights are just a few. All require constant-current LED drivers that ...

A common method for driving multiple power LEDs is through two parallel strings. This inexpensive and less critical driver circuit can provide a lower voltage. However, the driver circuit must deliver twice the current of other methods and needs a ...

Peter Demchenko EDN This Design Idea circuit regulates the current through one or more LEDs, making it almost independent of supply voltage. Its main advantage is a very small dropout voltage, which can be less than 100 mV. The design could find ...

The circuit in Figure 1 represents a simple and inexpensive way to provide additional bicycling safety. A conventional bicycle-generator lighting system works with the circuit to provide safety lighting for several minutes after the bicycle has ...