A low forward voltage of redundant power supplies design without IC

抄録

Fault-tolerant and redundant power supplies are often used in systems that require high reliability, such as data servers, telecommunications, and power supplies for autonomous driving function. Using diode is a simple method to keep uninterrupted power supply that is, using diode in series with each power path to become “Diode ORing”. However, in high current application, the voltage drop of the diode will result huge power loss. Even if that a low voltage drop of Schottky diode is adopted. This article proposes a simple P MOSFET control circuit that can implement the function of P MOSFET as a diode, that is, to ensure unidirectional conduction of current and maintain a low conduction voltage drop, thereby reducing losses. The circuit has the advantages of low forward voltage drop, without IC control, no need for additional auxiliary power supply, and the ability to block current flow between different power supplies that is the reverse current blocking is achieved. A circuit for implementing ORing of two power supplies to increase system redundancy or power capacity is provided. Simulation results verify the feasibility of the proposed control circuit.