Speaker
Description
The bPOL48V is a DC-DC Point-Of-Load (POL) buck converter developed at CERN and characterized at RWTH Aachen University under the DRD7 program. The bPOL48V is designed to address power distribution challenges of next-generation high-energy physics experiments by enabling power delivery at higher voltages and lower currents in supply cables, thereby minimizing power losses. It supports a higher input voltage (48V) compared to existing solutions by using a CERN-designed GaN controller with a commercial GaN power stage. The bPOL48V has been characterized in various setups, and its performance results will be presented, covering efficiency, stability, and both emitted and conducted noise.
Summary (500 words)
The bPOL48V [1] is a newly developed DC-DC Point-of-Load (POL) buck converter designed by CERN’s EP-ESE group. The assemblies are being characterized under the umbrella of the DRD7 collaboration, a Detector R&D initiative aimed at developing future electronic systems and technologies for particle physics detectors. The bPOL48V addresses the need for high-efficiency, compact, and radiation-tolerant power distribution solutions in next generation high-energy colliders. In these systems, power distribution becomes increasingly challenging due to significant current demands at decreasing ASIC supply voltages, stringent material budgets, and operation in high-radiation and high-magnetic-field environments.
DC-DC conversion allows us to reduce the current on the long supply cables and thus to reduce voltage drops and Ohmic losses on these cables. The bPOL48V enables localized voltage regulation by stepping down from 48V to an adjustable output between 5V and 24V.
Currently DC-DC converters are implemented for example on “2S” CMS silicon strip modules that step down 12V to 1.25V. The bPOL48V offers a higher conversion ratio, resulting in reduced losses. Key to the bPOL48V’s performance is its use of Gallium Nitride (GaN) technology, which offers several advantages over traditional silicon-based devices. It features a radiation-hardened GaN controller ASIC developed at CERN, paired with a commercial EPC2152 GaN power stage. This combination allows for: high-voltage operation with improved thermal performance, low conduction and switching losses, radiation tolerance up to 50 Mrad and about 2.2×10¹⁴ p/cm² (30 MeV), magnetic field compatibility above 4 T, and efficient operation with small PCB air-core inductors ranging from 200 to 500 nH, using a switching frequency between 0.5 and 3 MHz [1].
Different versions of the bPOL48V have been delivered to RWTH Aachen University for extensive characterization. The converters are evaluated for their efficiency, which exceeds 90% across a broad operating range. Furthermore, both line and load regulation are measured, with particular attention given to their dependence on temperature variations. Radiated electromagnetic noise is characterized, and improvements are investigated through the application of a custom-designed shield. Conducted noise is also measured at both the input and output terminals of the converter. The bPOL48V has been specifically engineered to minimize differential-mode conducted noise at its output. The output differential-mode noise is measured and compared with simulation results.
This report will present an overview of these characterization measurements and summarize the performance results of the bPOL48V.
[1] CERN EP-ESE group, bPOL48V GaN-based radiation and magnetic tolerant buck converter, https://power-distribution.web.cern.ch/ASICS/
