Patent ID: 7667520

Claim:
A level shift device, comprising: a level shift circuit which converts a voltage level of a single input signal into a first signal and a second signal; and a duty correcting circuit which reduces a difference in a duty ratio between said first signal and said second signal based on said first signal and said second signal; wherein said level shift circuit comprises an R-S latch circuit which converts a signal whose voltage level is being converted into said first and second signals, and wherein said duty correcting circuit comprises: a first NMOS transistor which has said first signal connected to its gate, and has its source grounded; a second NMOS transistor which has said second signal connected to its gate, and has its source grounded; a first inverter which has its input terminal connected to a drain of said second NMOS transistor, and has its output terminal connected to a drain of said first NMOS transistor; a second inverter which has its input terminal connected to said drain of said first NMOS transistor, and has its output terminal connected to said drain of said second NMOS transistor; a first buffer which level-shifts an output signal of said first inverter; and a second buffer to which an output signal of said second inverter is inputted.