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 ...
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 current through the ...
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 offer a high dimming ratio, high ...
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 ...
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 use on LED strips, ...
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 ...
Keeping low-voltage outdoor lights illuminated takes some effort. Bulbs burn out, and connections corrode. HB LEDs (high-brightness light-emitting diodes) seem like acceptable replacements, but most are available only in surface-mount packages, ...
High-power LEDs challenge electronics engineers to design accurate and efficient, yet simple, driver circuits. Conventionally, driving high-power strings with accurate current requires dedicated switching regulators. Choosing a discrete driver ...
Tom Gay EDN Most current microcontrollers offer I/O ports that can change their functions during program execution. As outputs, the circuits can sink and source reasonably large amounts of current. This Design Idea shows three alternative methods ...