INPUT OUTPUT BUFFER, INPUT BUFFER, AND OUTPUT BUFFER

摘要

PROBLEM TO BE SOLVED: To provide an input output buffer capable of protecting its circuitry against a voltage signal received externally independently of application / non application of operating power. SOLUTION: The input output buffer is provided with a power supply generating circuit 16 that converts the voltage signal EB externally received into a proper level corresponding to a high level power supply VDE to generate a reference power supply VDO. The power supply generating circuit 16 is provided with diode-connected transistors Pt 11 to Pt 15, and the back-gates of the transistors Pt 11 to Pt 15 are connected to nodes having levels other than the levels of the high level power supply VDE and a low level power supply VSS. Thus, it is prevented that a high voltage is applied between the gate and the back-gate of the transistors Pt 11 to Pt 15 at the application of the external voltage signal EB to the input and output buffer independently of application / non application of the high level power supply VDE. COPYRIGHT: (C)2004,JPO