Portable flashlights have been one of the earliest adopters of LEDs, and LED-based flashlights are now the most prevalent solutions available on the market. However, many of these designs use simple resistor circuits that contribute to poor LED performance, decreased functionality, and diminished lifetimes.
Industrial, military, and sport flashlight designers are some of the growing number of engineers recognizing the advanced control and functionality that an MCU provides. With significantly longer lifetimes and better efficiencies than an incandescent bulb, LED lighting turns on instantly without any warm-up, provides accurate light placement, produces no radiated heat, and can perform well in both indoor and outdoor applications. The addition of an MCU powering and managing the LED provides opportunities for control of custom lighting patterns / sequencing, user interface control, and increased efficacy (lm/W) resulting in longer battery life at greater lumen output. Additionally, an MCU implementation benefits from the ability to modify or add functionality via a simple program update versus a hardware redesign.
The High Power LED Flashlight Demonstration is a collaborative platform showcasing the capabilities of Microchip, Cree®, Airspeed, and Energizer®. The 10W, ~1000 lumen premium flashlight, features a Microchip MCP1703, MCP14628 and PIC12F752 controlling a >90% efficient buck power supply dropping 7.2V, supplied by Energizer® Ultimate Lithium batteries, to 3.3V/3.0A driving a single Cree XLamp® XM-L LED. The entire assembly fits inside an aluminium hard anodized enclosure, provided by Airspeed LLC, and is fully ruggedized for use in most any environment. With almost 1000 lumens at 10W, light output is approximately half of a single automotive headlamp while maintaining ~100 (lm/W) efficacy for efficient operation.