Increasing Electrical and Thermal Performances of VRMs by Using Folded Flexible Substrate

Electrical and thermal performance of rigid PCB based voltage regulator modules (VRMs) are modeled and simulated with FEA Multiphysics simulation tool. Then, a new concept of building power converters on folded flexible substrates is proposed to solve the issues existing in previous solutions. The newly proposed concept is then analyzed, simulated and compared with previous ones. A converter phase block implements the proposed concept was designed, built and tested. Test result shows at 2.5MHz, 12V to 1.2V 40A operation, the proposed converter can achieve 62.5A/cm² planar power density and the measured module temperature is only 3.06°C above heat sink temperature.