A Novel High Power LED Module Design on Aluminum Board (COAB) by Packaging Multi-Die in both Series and Parallel

Abstract

To decrease the LED operating temperature this paper presents a novel high power LED COAB (Chip on Aluminum Board) bonding method, the heat dissipation performance was studied by packaging the multi-die in the combination of series and parallel. The trade-off parameters were the bonding distance and driving voltage. The dies were connected in a combination of 3 dies in series and 3 sets in parallel (3x3 square matrix pattern). If the separation distance of die bonding was 1.5mm, the temperatures on the top surface of center LED with driving voltage of 8 (9) Volts was 75.2 (90.5) ℃. On the other hand, if the separation distance reduced to 1.0mm with the driving voltage of 8 (9) Volts, then the temperatures at the top surface of center LED would be increased to 75.7 (115.2) ℃. Thus for the LEDs efficiency kept at 80％ of those at 25℃, the final choice of die bonding distance and driving voltage were 1.0mm and 8V, respectively.