Bi-directional switch, alternating-current two-wire switch, switching power source circuit, and method of driving bi-directional switch

A method of driving a bi-directional switch,

• wherein the bi-directional switch 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 the semiconductor stack;
• a first gate electrode formed between the first electrode and the second electrode;
• and
• a second gate electrode formed between the first gate electrode and the second electrode, and
• said method comprising steps of:
• determining whether or not a potential of the first electrode is higher than a potential of the second electrode, in a transition period corresponding to a transition state at a time when the semiconductor device is activated;
• applying, to the first gate electrode, a voltage that is relative to the potential of the first electrode and lower than a first threshold voltage of the first gate electrode, and apply, to the second gate electrode, a voltage that is relative to the potential of the second electrode and higher than a second threshold voltage of the second gate electrode, when the potential of the first electrode is higher than the potential of the second electrode in a transition period corresponding to a transition state after the semiconductor device starts being activated;
• and
• applying, to the first gate electrode, a voltage that is relative to the potential of the first electrode and higher than the first threshold voltage, and apply, to the second gate electrode, a voltage that is relative to the potential of the second electrode and lower than a second threshold voltage, when the potential of the first electrode is lower than the potential of the second electrode in the transition period.