Signal amplifying device

A signal amplifying device comprising:

• a sense amplifier for receiving first and second signals having respective logical levels from memory means, and for, when activated in response to an active signal, outputting third and fourth signals having respective logical levels in accordance with the logical levels of the first and second signals;
• and
• output means comprising an output terminal, first means and first, second, third and fourth transistors, each of said first, second, third and fourth transistors having a drain, a source and a gate, for outputting an output signal having one of a first level and a second level based on said third and fourth signals and said active signal;
• wherein said source of said first transistor is connected to said drain of said second transistor, said source of said second transistor is connected to said output terminal and said drain of said third transistor, and said source of said third transistor is connected to said drain of said fourth transistor;
• said first means receives said active signal, and said third and fourth signals, and generates fifth and sixth signals having one of a first level and a second level based on said active signal, said third signal and said fourth signal;
• said gates of said first and third transistors receive said fifth signal and said gates of said second and fourth transistors receive said sixth signal;
• said first and fourth transistors are turned off in order to set said output terminal of said output means to a high-impedance state when said fifth signal is at one level and said sixth signal is at the other level of said first and second levels;
• said output signal is output from said output terminal when a level of said fifth signal is the same as a level of said sixth signal;
• a level of said output signal is different from said level of said fifth signal;
• and
• said output signal has either a high logical level or a low logical level.