Circuit Board Comparison
Metal core PCB and standard FR-4 are commonly used circuit board materials in conjunction with Power LEDs. Henkel’s Thermal Clad dielectric is a thin, thermally conductive layer bonded to an aluminum or copper substrate for heat dissipation (see illustration below). The key to Thermal Clad’s superior performance lies in its dielectric layer.This layer offers electrical isolation with high thermal conductivity and bonds the base metal and circuit foil together. Other manufacturers use standard prepreg as the dielectric layer, but prepreg doesn’t provide the high thermal conductivity and resulting thermal performance required to help assure the lowest possible operating temperatures and brightest light output for high-intensity LEDs.Thermal Clad circuit board materials are available from Henkel in three different thermal conductivities, High Power Lighting (HPL), High Temperature (HT) and Multi-Purpose (MP).
There are several options available for thermal management of Power LEDs. The most critical thermal path in the stack is the one with the highest thermal resistance. Good practice suggests that you reduce the thermal resistance of that layer with Thermal Clad dielectric instead of FR-4.