Infineon Technologies has developed industry’s first radiation-hardened (rad-hard) buck controller with an integrated gate drive for space systems, writes Nick Flaherty.

The RIC70847 is designed for point-of-load power rails in commercial space systems and other extreme environments, including the digital processing required for autonomous operation.

The controller integrates a radiation-hardened 17.1 V buck controller with a 5 V half-bridge gate drive with an output of 0.6–5.25 V.

The hermetically sealed controller works seamlessly with logic-level transistors and meets the Mil-Spec temperature range of -55 to 125 C. It also tolerates a total ionising dose of up to 100 krad and single event effects up to 81.9 MeV·cm²/mg.

A fixed switching frequency peak current mode control algorithm and externally adjustable slope compensation ensures stable operation over a wide range of conditions. The switching frequency is programmable from 100 kHz to 2 MHz with a single resistor, or it can be synchronised to an external clock or another RIC70847 for multiphase operation.

There are multiple integrated fault protection mechanisms with load-line regulation (also referred to as adaptive voltage positioning or droop regulation), where the output voltage is adjusted dynamically based on the load current. This significantly reduces the output capacitance. High step-down voltage ratios, combined with the integrated 5 V half-bridge gate driver simplify the design process and minimise the component count.

The buck controller is used on an evaluation board that features an integrated dynamic load step circuit for transient testing and wide support for a range of output capacitance and inductor configurations.