Present practice of power packaging for DC/DC converters

This paper presents the results of a detailed benchmarking of the status of power packaging of DC/DC converters in the 100 watt range. This work was carried out as part of the StatPEP project which was co-sponsored by the PSMA and PEI Technologies. This benchmarking has established the present best practice in the power electronic packaging of DC/DC power converters being manufactured at present. Ten DC/DC power supplies were identified. The units included two from government and space applications, seven telecom units and one common industrial unit. The main specifications of these supplies are rated power of ∼ 100 W, input voltage of 48 V and single output voltage (V₀) as low as possible in the range 5 V to 2 V. Electrical and thermal properties were measured to confirm the individual data sheet specifications. The investigation comprised an analysis of the physical structure of converters, the nature of external packaging, the type of base plates, substrates and potting compounds used as well as the converter's power / energy / current densities. Also addressed was the interconnect between circuit components, the assembly technology used, overall numbers of components and solder joints and magnetic components (packaging type, technology, level of integration). Of particular interest in the benchmarking process is an analysis of how packaging is used to address thermal and current density issues as well as the identification of suitable figures of merit to quantify the status of power packaging and allow progress be monitored over time.