Power Supply Profile
Instantiations of this profile are intended to function as primary-to-secondary power converters, producing the secondary voltage rail(s) that are distributed to other nodes.
The ‘Local POL Power Conversion’ section mentions one “or more secondary voltage rails” being produced by the PS node. One voltage rail (typically +5 or +12 V) is meant to support POL conversion to the working voltages needed by all of the nodes. Examples of the other secondary voltage rails could be balanced analog supplies (e.g., +/-15V) if needed by any of the interface expansion modules.
To better control the paths of return currents, most PS node designs are expected to use isolated DC-DC converters. For systems where control of return currents is not an important issue, non-isolated converters can be used.
The reliability requirements of some systems will drive the designers to add redundant PS nodes. Redundant PS nodes are typically A/B redundant, and may be diode or switch coupled to one distribution network, or they may be wired to redundant distribution networks, and diode or switch coupled to the loads (other JAS nodes).