Patent ID: 7649383

Claim:
A bidirectional level shift circuit used in a bus system performing bidirectional communication among a plurality of equipments, comprising: a semiconductor device connected between a first signal line for performing bidirectional communication using a first voltage level and a second signal line for performing bidirectional communication using a second voltage level higher than the first voltage level, wherein said semiconductor device comprises a plurality of ON/OFF control transistors connected between the first signal line and the second signal line, at least one of the plurality of ON/OFF control transistors has a control terminal connected to a first power supply terminal which receives the first voltage level, and at least one of the other plurality of ON/OFF control transistors has a control terminal connected to an intermediate voltage level between the first voltage level and the second voltage level, and wherein said semiconductor device further comprises a bias circuit connected between the first power supply terminal receiving the first voltage level and the second power supply terminal receiving the second voltage level, so that said bias circuit generates an intermediate voltage between the first voltage level and the second voltage level.