Small size, high power on-board power supply using Cu-alumina PCB with thermal-vias

A printed circuit board (PCB) consisting of conductor (Cu) and glass epoxy material laminated on metal aluminum plate has been used commonly for high power on-board power supplies. Reducing unit size has been required, particularly for the application to communication equipment. To miniaturize the improvement of efficiency and increasing the frequency have been important subjects, but in addition to these, such technology as bringing the unit to high density is becoming very important. In this case, a multilayer with good thermal conductivity has been required for the high power on-board power supply, however, a PCB having glass epoxy (insulation) has a problem due to insufficient thermal conductivity in the case of the multilayer system. Therefore, we developed a high power on-board power supply using a Cu-alumina PCB with good thermal conductivity in addition to the employment of thermal vias.