Tri-state circuit

Abstract

Abstract PURPOSE:To decrease the number of constituent transistor (TR) by connecting respective drains of input insulation type field effect transistors (MISFET) to respective gates of output-stage MISFETs. CONSTITUTION:When a control signal CT is at 'H', a node N2 is held at the level 'H' through an MISFET 3 and a node N1 is held at an MISFET 2. At this time, MISFETs 1 and 4 are off, so there is no continuity between the nodes N1 and N2. An N channel MISFET 7 which has its gate input at the 'L'-level node N1 is therefore off and a P channel MISFET 8 which has its gate input at the 'H'-level node N2 is also off, so that an output OUT is in a high impedance state. In such a case, the levels at the nodes N1 and N2 are determined regardless of the state of an input signal I1 and the output has high impedance.

Inventors

• 👤 Toshiaki Hoshi
• 👤 俊明 星

Bibliographic Details