US Patent 9806519 Input redundant circuit

An input redundant circuit according to the present disclosure may include: a core power supply unit; a first input port connected to a first input voltage; a second input port connected to a second input voltage; a relay unit connected to the first input port and the second input port to supply one of the first input voltage and the second input voltage to the core power supply unit; and a surge current limiting unit coupled to the relay unit, configured to limit a surge current generated when the relay unit is switched between the first input voltage and the second input voltage.