Design and Implementation of DC Switching Power Conversion and Power Integrity in Prototyping a Load-balanced Birkhoff-von Neumann Switch

• Main Authors: Lin, Jeng-Yi, 林政億
• Other Authors: Lee, Duan-Shin
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/03082572746777592765

碩士 === 國立清華大學 === 通訊工程研究所 === 98 === Load-balanced Birkhoff-von Neumann switch, known as scalable and theoretical 100% throughput achievable, is widely discussed in many famous international research groups, and we organized a team to realize a prototype of this switch architecture. In this paper，we focus on the efficient power subsystem design to power all the functional modules and power integrity design to restrict jitter effect of this switch prototype. First of all, our power subsystem includes overload fuse protection and hot-swap controller to meet two priority criteria: safety and reliability. AdvancedTCA is a newly defined specification aiming at telecommunication market, and we purchased a standard AdvancedTCA chassis as a platform to build our prototype on it. This chassis provides two redundant 48VDC feeds to power the printed circuit board (PCB) inserted. To operate low voltage functional modules, such as FGPA, SDRAM, and SRAM, DC-DC conversion modules are necessary to convert 48VDC to the desired voltages: 12V, 5V, 3.3V, 2.5V, 1.8V, 1.5V, 1.25V, and 0.75V. Inheriting fundamental boost and buck circuits, conversion modules are designed to generate required voltages. Performance shows these conversion modules generate target voltage levels within 10% of accuracy. Besides, for the ease of debugging, isolation module is also designed to isolate power subsystem and functional modules during testing. Solid power integrity design can mitigate jitter and further improve prototype stability. We address this design by two approaches: PCB layer stack allocation and decoupling capacitor deployment. Interleaving power planes in the PCB layer stack not only isolates crosstalk effect but also eliminates unwanted parasitical inductance which mainly causes power drop. Densely deploying decoupling capacitors near power drains to stabilize voltage levels upon sudden current draws.