| 摘要 |
PURPOSE:To decrease the number of terminals of the package by giving the potential change of more than three points to one unit of the external input terminal to secure the logic and thus to deliver three kinds of the truth value and thus saving one external input terminal. CONSTITUTION:When input voltage Vin's absolute value ¦Vin¦ is more than VSS and at the same time less than threshold voltage (¦VTH¦), enhancement FETQ1 does not conduct. Ant the output of inverter circuit 1 features the L-potential under VO VSS, and both V3 and V4 feature the L-potential since Vin is supplied to the input of NOR circuit 2 and 3. When Vin is under the 2nd state, Q1 conducts. And ¦VO¦<¦VTH¦ is secured owing to the relation of the conductance of Q1 as gm2 of gm1>>Q2, and thus circuit 1 does not conduct yet with the output of L and V3 of H respectively. With Vin under the 3rd state, ¦VO¦>¦VTH¦ is satisfied with the output of L for circuit 1 and V3 of L each. And V4 features H. In such way, the three kinds of the truth value can be delivered through one unit of the external input terminal. |
