PURPOSE: To prevent the deterioration of a tunnel oxide film by preventing the generation of a high voltage pulse with a writing control circuit when a supply voltage is a certain value or above with the output of a supply voltage detecting circuit.
CONSTITUTION: The titled device is provided with a supply voltage detecting circuit 2 to output the signal of the level different from an ordinary one when the supply voltage goes to a certain value or above and a writing cycle operating prohibiting means 11 to receive the output of the supply voltage detecting circuit 2, to prohibit that the writing control circuit enters the writing cycle when the supply voltage goes to a certain value or above and to prevent a high voltage pulse. Namely, the writing control circuit is controlled by the output of the supply voltage detecting circuit 2, when the supply voltage goes to a certain value or above and other input signal is inputted so as to enter the writing cycle, the circuit does not enter the writing cycle and the high voltage pulse does not occur. Thus, it can be prevented that an excessive electric field is added to the tunnel oxide film and the deterioration of the tunnel oxide film is hastened.
| JPH0472677 | THIN-FILM TRANSISTOR MEMORY |
| JPH06312544 | PRINTER |
TOYAMA TAKESHI
KODA KENJI
ANDO NOBUAKI
KOBAYASHI SHINICHI
