The benefit of diode-ORing supplies is that the power system achieves fault-tolerant redundancy with the addition of simple, passive diodes. However, at currents above a few amps, the diodes dissipate watts, requiring heat sinks or additional PC board area for heat dissipation. In low voltage applications, the diode voltage drop eats up precious voltage headroom. Both of these problems can be fixed with an ideal diode, which uses MOSFETs to emulate a low-drop diode. As seen on the previous slide, in a diode-OR the highest supply sources all or most of the current while the other stands by idly. That is, only half of the available resources are being used. The next step-up in reliability is obtained when the two supplies share the load current.