A Burn-in Test Station for the ATLAS Phase-II Tile-Calorimeter Low-Voltage Power Supply Transformer-Coupled Buck Converters

Abstract

The upgrade of the ATLAS hadronic tile-calorimeter (TileCal) Low-Voltage Power Supply (LVPS) falls under the high-luminosity LHC upgrade project. This article serves to provide an overview of the development of a burn-in test station for a Phase-II upgrade LVPS component known as a Brick. These Bricks are radiation hard transformer-coupled buck converters that function to step-down bulk 200 V DC power to the 10 V DC power required by the on-detector electronics. To ensure the high reliability of the Bricks, once installed within the TileCal, a burn-in test station has been designed and built. The Burn-in procedure subjects the Bricks to sub-optimal operating conditions that function to accelerate their aging as well as to stimulate failure mechanisms. This results in elements of the Brick that would fail prematurely within the TileCal failing within the burn-in station or to experience performance degradation that can be detected by followup testing effectively screening out the ’weak’ sub-population. The burn-in station is of a fully custom design in both its hardware and software. The development of the test station will be explored and the preliminary burn-in procedure to be employed will be presented. The commissioning of the burn-in station will be presented along with a summary and outlook of the project.

A Burn-In Apparatus for the ATLAS Tile Calorimeter Phase-II Upgrade Transformer-Coupled Buck Converters

“…The reliability of an electronic device, such as a Brick, can differ from its predicted design reliability due to latent and patent defects associated with its production and that of its components. Quality assurance testing is to be undertaken on all fLVPS Bricks postmanufacturing to address this phenomenon [14], the purpose of which is to increase the reliability of the surviving population by screening out the sub-population of Bricks that exhibit such defects. As seen in Figure 4, the quality assurance procedure is composed of five distinct tests, namely an automated visual inspection, X-ray scan, initial testing, Burn-in, and final testing.…”

“…Burn-in is required as some patent and/or latent defects may not have been detected by the initial testing. Burn-in is primarily focused on detecting patent defects that appear during the early life of the Bricks, but it should be noted that latent defects, which usually appear during normal operation, can be converted into patent defects via the application of external overstress [16]. Burn-in testing entails subjecting the Bricks to a Burn-in procedure in which they are exposed to overstress conditions, such as an increased operating temperature and applied load, in relation to their nominal operating conditions.…”