MicroTCA (µTCA) is designed to build flexible and reliable (high availability) embedded systems. A µTCA system consists of up to 12 Advanced Mezzanine Cards (AMC), 2 cooling units (CU), 2 MicroTCA Carrier Hub (MCH) and 4 Power Modules (PM). A single power module is unlikely to meet the power requirements of a fully loaded µTCA system; hence load sharing mode is used in these systems, where the power requirements are met by having multiple PM.
Power Modules can also be configured to improve reliability by redundancy, but this will increase the number of PMs required in a system. Often load sharing is required, and PM redundancy is very desirable to improve the reliability of the system. However PM redundancy is sometimes disregarded due to increased costs, and in some cases it is not possible to achieve redundancy due to system constraints – for example, a chassis which has 2 PM slots and require them to be in load-sharing mode. For these systems, we discuss the additional costs of having PM redundancy - the number of additional PMs required, and how a cost-effective solution can be achieved. In many cases PM redundancy can be achieved at no additional cost.
The power module is an integral part of the µTCA system. The PM’s primary function is to provide management and payload power, but like any other FRU, it must be IPMI compliant. Although the PM has the intelligence to autonomously bring up the MCH and the CU, the MCH is required to provide sophisticated features such as PM redundancy. Figure 1 shows a typical µTCA system consisting of 12 AMCs, 2 MCHs and 2 CUs and highlights the parts of the power system.
Figure 1: µTCA System with 12 AMCs, 4 PMs, 2 MCH, 2 CU
Consider the system in Figure 1, with each of 12 AMCs drawing 80W of power. Today’s PMs are able deliver between 400 to