公开(公告)号：JPH08288826A

公开(公告)日：1996-11-01

申请号：JP7890596

申请日：1996-04-01

Applicant: CONS RIC MICROELETTRONICA

Inventor： FURANKO RENCHINI ,  JIYORUJIO KATANZARO

IPC: H03K19/00 ,  H03K19/003 ,  H03K19/0175 ,  H03K19/0948

Abstract: PROBLEM TO BE SOLVED: To provide a three-state CMOS output buffer which is made structurally different from a known circuit and conquer the fault of known circuit while being made appropriate for the purpose of use in an integrated circuit required to connect various voltage power sources. SOLUTION: A pull-up transistor M15 has an auxiliary circuit 9 for holding a switchable bulk line 2, which is connected to a voltage power source VDD while the voltage of output node 4 is not higher than the power supply voltage VDD, while having a bulk electrode connected to the switchable bulk line 2. Then, a 1st logic gate 3 is equipped with means M17, M11 and M12 for transmitting the voltage of output node 4 to the switchable bulk line 2 when the voltage of output node 4 exceeds the power supply voltage VDD.