Radiation-Hard DC-DC Converter

The upgrade of the physics experiments for the High Luminosity LHC (HL-LHC) at CERN is currently driving the development of new and more efficient powering schemes to cope with the increase of power demanded by the new high-density front-end electronics boards. Due to the high radiation levels of up to hundreds of Mrad at the HL-LHC, commercial DC-DC converters cannot be used in these powering schemes. Therefore, a critical need exists for custom-designed radiation-hard DC-DC converters to be used in the planned upgrades of the ATLAS and CMS detectors of the LHC, and in other planned future experiments. These converters must also function in high magnetic fields and be implemented within a small form factor with low mass. Alphacore will develop a novel hybrid Gallium Nitride (GaN) and silicon CMOS integrated module DC-DC converter. The converter will have built-in self-test (BIST) circuitry that can be used to monitor the converter’s health during the long HL-LHC experiments. The converter will exhibit the following specifications: Input voltage of 18V (and later 24V) regulated down to an output voltage of 1.0V – 3.3V, with at least 7A maximum load current, Exhibits a minimum of 80% efficiency, Includes radiation-hard built-in-self-test (BIST) to monitor critical performance parameters and calibrate controller parameters for high radiation conditions and over converter lifetime, Integrated, compact, single-module DC-DC converter solution. This solution includes a customized CMOS chip, as well as the GaN-based DC-DC converter’s power stage. These components will be integrated to provide a single-package solution. The GaN and CMOS-based converter functions at total ionizing dose (TID) levels ≥200 Mrad/Si as well as high tolerance to single event effects and displacement damage, which makes it an excellent candidate for use in the HL-LHC. Within Phase II, a DC-DC converter module will be designed and fabricated, based on the studies performed in Phase I. The module will include GaN devices for the converter’s power stage, along with a custom-designed IC with BIST and monitoring functionality and the converter’s controller and driver circuitry. The GaN-based module will be fabricated and tested for functionality conforming to design specifications, as well as performance under a variety of extreme radiation conditions that approximate the conditions that will exist inside the HL-LHC. The designed converter will find many potential commercial applications, (power systems in space satellites, defense systems, powering of large medical imager scanners, etc.) due to its high efficiency and compact size that originates from the high switching frequency and lack of large passive devices. Large scanners used in medical imaging (combo scanners for MRI and SPECT as an example) require compact powering schemes for up to 20,000 tightly spaced readout channels functioning in high magnetic fields and with low levels of ionizing radiation. Alphacore’s converter meets all of these specs. High Energy Physics and Nuclear Physics research are major fields where the GaN based DC-DC converter chips will be used. The size of this market can be put into perspective knowing the fact that the LHC alone has used $10B of funding so far and will require several billion dollars in the near future for upgrades. There are also several other planned large-scale experiments with millions of readout channels, including the International Linear Collider and the Electron Ion Collider. Alphacore, Inc. will use a novel combination of gallium-nitride and CMOS microelectronic technologies to develop a radiation-hard power converter that is currently critically needed for the planned upgrades of the Large Hadron Collider.