Patent ID: 8362544

Claim:
A switching device that electrically connects or disconnects a first terminal and a second terminal to/from each other, comprising: a semiconductor layer; a drain electrode that is formed in the semiconductor layer, the drain electrode being connected to the first terminal; a source electrode that is formed in the semiconductor layer, the source electrode being connected to the second terminal; a gate insulator that is formed on the semiconductor layer between the drain electrode and the source electrode; a floating gate that is formed on the gate insulator, the floating gate retaining a charge therein; a plurality of tunnel gates that are formed on the floating gate, each tunnel gate supplying a tunnel current determined by a driving voltage applied thereto to charge or discharge the floating gate; a driving section that connects or disconnects the drain electrode and the source electrode to/from each other by controlling the driving voltage to cause at least one tunnel gate to charge or discharge the floating gate; a selecting section that selects at least one of the plurality of tunnel gates; and a supply section that supplies the driving voltage output from the driving section to the selected at least one tunnel gate.