Patent ID: 8526207

Claim:
A bi-directional switch comprising a semiconductor device and a control unit wherein: said semiconductor device includes: a semiconductor stack formed on a substrate, having a channel region, and including one of (i) a nitride semiconductor and (ii) a semiconductor including silicon carbide; a first electrode and a second electrode formed at an interval on said semiconductor stack; a first gate electrode formed between said first electrode and said second electrode; and a second gate electrode formed between said first gate electrode and said second electrode, and said control unit is configured to: apply, to said first gate electrode, a voltage that is relative to a potential of said first electrode and lower than a first threshold voltage of the first gate electrode, and apply, to said second gate electrode, a voltage that is relative to a potential of said second electrode and higher than a second threshold voltage of the second gate electrode, when the potential of said first electrode is higher than the potential of said second electrode in a transition period corresponding to a transition state after said semiconductor device starts being activated; and apply, to said first gate electrode, a voltage that is relative to a potential of said first electrode and higher than the first threshold voltage, and apply, to said second gate electrode, a voltage that is relative to a potential of said second electrode and lower than a second threshold voltage, when the potential of said first electrode is lower than the potential of said second electrode in the transition period.