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Description
This paper describes a small-size and easy to use hybrid DC/DC converter controller with integrated switch. It integrates in one component all the complex functionality required for low power isolated DC/DC converters in space applications, allowing a reduction of size, cost, and design effort.
In a satellite there are tens of low power isolated DC/DC converters that generate the voltage levels needed by control circuitry of the main electronics units. In general, these auxiliary power supplies have to be directly connected to the main bus and, in some cases, directly to the output of the solar array. Due to their low power level, the size and cost are the main performance indicators. However, even though these power supplies are supposed to be simple, they are relatively complicated to implement because most of their building blocks have to be implemented with discrete EEE components.
The described hybrid DC/DC converter controller with integrated switch will reduce the effort of designing custom DC/DC converters to the design of magnetics components, the selection of the rectifier diodes and selection of filtering input and output capacitors.
The proposed hybrid component comprises a power MOSFET, an innovative PWM controller ASIC and few discrete components on ceramic substrate in hermetic package. It combines the advantages of high integration and sophisticated functionality of the ASIC with flexibility of the hybrid, which allows using different semiconductor technologies in the same component and adjusting the component settings according to the particular demand.
The PWM controller ASIC includes an integrated start-up circuit that may be directly connected to the satellite's main power bus, an independent protection that will switch off the PWM controller in case of external or internal failure, fully redundant gate driver, magnetic feedback support and features numerous settings and detection possibilities.
It is able to start directly from the power bus between 15V and 120V without any additional start up voltage required. Due to the integrated low side power transistor, Flyback and Forward converters can be realised with minimum additional components needed for those topologies.
Magnetic feedback support integrated in this controller offers a special advantage of optocoupler-free isolated converter design.
