High availability systems often employ dual feed power distribution to achieve redundancy and enhance system reliability. ORing diodes join the feeds together at the point of load, most often using Schottky diodes for low loss. MOSFET-based ideal diodes can be used to replace Schottky diodes for a signifi cant reduction in power dissipation, simplifying the thermal layout and improving system effi ciency. Figure 1 shows the LTC4355 and LTC4354 combining the inputs and returns in a –48V, 5A dual feed application. This solution reduces the power dissipation from 6W using Schottky diodes to just 1.1W with MOSFETs.

Ideal Diodes Protect Against Power Supply Wiring Errors.pdf