DC-DC Boost Converter Design with External Control via Optical Fiber for Cryogenic Applications

To provide the necessary bias voltage for Silicon Photomultiplier (SiPM) sensors within the second module of the DUNE (Deep Underground Neutrino Experiment) far detector, it is essential to design power supply systems capable of delivering highly stable and low-noise voltages. While conventional designs allow these power units to be positioned outside the time projection chambers filled with liquid argon (LAr), the vertical drift configuration of DUNE introduces new constraints.In this design, the Photon Detection System (PDS) electronics, including readout and biasing components, must be integrated directly onto the cathode plane, which operates at a high DC potential of -300 kV. Due to this, direct electrical links between the SiPMs and external control or power interfaces are not feasible. Instead, energy is transmitted via optical fibers using a Power over Fiber (PoF) approach.PoF systems typically output only a few volts, with voltage levels varying according to the load current. The SiPMs intended for use in this setup require a 48 V DC bias, although alternative models from other manufacturers may require a 36 V DC supply. To address this, the solution presented in this work introduces a cryogenically operable step-up DC-DC converter designed to generate a stable, ultra-low-noise 48 V output. Additionally, the output voltage can be dynamically adjusted using a dedicated control signal transmitted via optical fiber.The proposed converter employs a boost topology with components specifically chosen and tested for reliable operation at cryogenic temperatures. Regulation is managed through an analog control system based on a Type III compensator, ensuring precise voltage control under varying conditions.