Patent ID: 7019563

Claim:
A waveform shaping circuit which, on the basis of a logical threshold value, discriminates a level and shapes a waveform of an input signal which changes between a first power supply potential and second power supply potential, characterized by comprising: first control potential setting means for generating a first control potential; second control potential setting means for generating a second control potential which changes in the same direction as the input signal in accordance with a change in input signal; output means which comprises a first transistor of a first conductivity type having a gate terminal to which the first control potential is applied, and a source terminal to which the second control potential is applied, and a second transistor of a second conductivity type having a source terminal to which the first power supply potential is applied, and a drain terminal to which the drain terminal of said first transistor is connected, and which outputs an output signal having a potential of the drain terminals of said first and second transistors; and reset means for applying a reset signal for turning off said second transistor to the gate terminal of said second transistor, wherein said first control potential setting means generates the first control potential which reverses a magnitude relationship with the second control potential when the input signal reaches a vicinity of the logical threshold value, and said output means generates an output signal having a predetermined potential on the basis of the first control potential, second control potential, and reset signal.