DPP - Digital Payload Processor- Power Daughter Board

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The project objective is to design power converters matching the need in a RUAG DPP reference design, including a thermal concept transporting heat from digital and power circuits, based on a heat pipe concept. The electronics investigate the use of GAN-FET transistors.

Two designs with different topologies have been selected to optimise the converter efficiency.


The LVHC design aims to supply high performance processing elements, e.g. FPGAs, which require low voltages <1V at currents of up to 50A.


The LVMC supply is intended for voltages in the range of 3V to 12V and a power class around 20W to 50W. The design is based on a converter generating an intermediate voltage and one or several Point of Load converters placed close to the user circuit.

A concept for heat trasportation using heatpipes is designed in the project.


Designing power converters in the 50W range for use in space require high efficiency. GAN-FETs are used for the low on-resistance but introduce design challenges.

The voltage accuracy requirement for the digital parts is stringent. With high currents, low impedance is of great importance as each mOhm causes important voltage drop and dissipation.

The heat generated in digital parts running at high frequencies constitute a challenge in conduction cooled systems. 


The product aims to facilitate design of a Digital Payload Processor using high speed digital circuits with low voltage, high current supply needs. 


Recent developments of high-performance processing boards using ASICs and reconfigurable FPGAs, e.g. as being used in digital payload processors or navigation signal generators, revealed the need for point-of-load converters providing output voltages below 1 V and currents up to 50 A, while maintaining tight voltage tolerances. Additionally, several supplies between 5V and 1.2V with lower currents are needed on such boards.

System Architecture

The most commonly used concept in industry is the distributed power concept based on an isolated intermediate converter and local non-isolating buck-type converters. This is the commonly known point-of load converter concept. An interesting alternative is based on a high efficient resonant converter located close to the load. Due to the zero voltage and/or zero current switching, the resonant power stage features a high efficiency. However, due to the very limited voltage control capability a dedicated pre-regulator is required. Also, direct conversion via isolated power converters have been taken into account. These concepts were compared regarding technical performance including EMC as well as economic arguments.


The project was started in 2018 with an MTR in June and a design review in December 2019. 

Current status

The project has been completed.

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