SG Designs - High, Power, LED, thermal, design

Electronic Product Design Services

High Power LED Cycle Lights

In 2007 we designed the electronics for a range of LED cycle lamps for a manufacturer of high-end CNC machined mountain bike components.

The driver is microprocessor controlled and incorporates a proprietary thermal throttling scheme to prolong LED life yet maximise light output. When the lamp is moving through the air at more than a few miles per hour it can sustain full output and stay cool. If the lamp is left on at full power in a hot environment with no airflow the micro cuts the LED drive current to maintain a safe heatsink (case) temperature. As soon as the case starts to cool the micro ‘throttles up‘ again. The driver controls LED current in four modes of operation selected by a pushbutton. Input power is from a 7.4V LiON battery pack and the driver can power either two LEDs or four LEDs up to 16 watts at more than 90% efficiency.

We also undertook thermal design and testing of the complete lamp; initial analysis was done in MathCAD followed by instrumented testing of a physical prototype.

Top Driver PCB, LED PCB and optics

Driver PCB, LED PCB and optics

MathCAD heatsink estimates

MathCAD heatsink estimates

Testing thermal performance in small wind tunnel