A signal input circuit and method and chip are disclosed. The signal input circuit includes a control signal input terminal configured for receiving a control signal; at least one common signal input terminal each configured for receiving a corresponding common signal; at least one first signal output terminal each configured for outputting a corresponding first signal; at least one first signal unit each configured for receiving said corresponding common signal and outputting said corresponding common signal as said corresponding first signal under control of said control signal; at least one second signal output terminal each configured for outputting a corresponding second signal; and at least one second signal unit each configured for receiving said corresponding common signal and outputting said corresponding common signal as said corresponding second signal under control of said control signal.