This question is in regards to an example application circuit that appears in the Linear Technology / Analog datasheet for the LTC4355, and is discussed in this article. The circuit uses ideal diode controllers to provide redundant power from dual power supplies in an AdvancedTCA application. While I'm familiar with diode-or'ing redundant power supplies (either with real diodes or ideal diodes), I'm used to seeing this on the high side only with low sides just tied together. I understand that AdvancedTCA uses negative supplies, and would therefore understand low-side-only diodes... but why both?
The AdvancedTCA specification does not seem to address this. It mentions that fuses are needed both high side and low side, but does not seem to require both high and low side diodes.