A circuit includes: a first type of swing reduction circuit coupled between an input/output pad and a buffer circuit; and a second type of swing reduction circuit coupled between the input/output pad and the buffer circuit, wherein the first type of swing reduction circuit is configured to increase a voltage received by respective gates of a first subset of transistors of the buffer circuit when a voltage applied on the input/output pad is equal to a first supply voltage, and the second type of swing reduction circuit is configured to reduce a voltage received by respective gates of a second subset of transistors of the buffer circuit when the voltage applied on the input/output pad is equal to a second supply voltage.