Patent ID: 7795916

Claim:
A level shift circuit for transmitting a signal from a circuit operated by a first power supply to another circuit operated by a second power supply, comprising: a level converter circuit, barrier gate circuit and a holding circuit; wherein said level converter circuit comprising: a first transistor of a first conductivity type having a source and a drain connected between said second power supply and a first output terminal and having a gate connected to a second output terminal; a second transistor of the first conductivity type having a source and a drain connected between said second power supply and said second output terminal and having a gate connected to said first output terminal; a first transistor of a second conductivity type having a source grounded and having a drain connected to the first output terminal; and a second transistor of the second conductivity type having a source grounded and having a drain connected to the second output terminal; wherein said barrier gate circuit receives an input signal of a first power supply system and outputs a gate signal of said first transistor of the second conductivity type and a gate signal of said second transistor of the second conductivity type; said barrier gate circuit receiving a standby signal to set said first and second transistors of the second conductivity type to off-states; and wherein said holding circuit holds said first and second output terminals at a constant voltage when said first and second transistors of said second conductivity type are both in the off-states.