| 摘要 |
PROBLEM TO BE SOLVED: To inhibit destruction of an element even when a high voltage to destroy the element is applied.SOLUTION: A semiconductor device which operates by an input of a first voltage and comprises a protection circuit 102 which varies a value of the first voltage when an absolute value of the first voltage is larger than a reference value. The protection circuit includes a control signal generation circuit 121 for creating a second voltage depending on the first voltage and outputting the created second voltage, and a voltage control circuit 122. The voltage control circuit has a source, a drain and a gate and includes a transistor which controls whether to vary the value of the first voltage depending on an amount of current flowing between a source and a drain when the second voltage is input to a gate as a control signal to cause the transistor to become an ON state of an OFF state according to the second voltage. The transistor further has an oxide semiconductor layer having a function as a channel formation layer and a band gap of the oxide semiconductor layer is equal to or more than 2 eV.SELECTED DRAWING: Figure 1 |
