HIGH-SPEED OUTPUT BUFFER CIRCUIT FOR HIGH AND LOW VOLTAGE OPERATIONS

摘要

PROBLEM TO BE SOLVED: To provide a circuit which can perform an operation of a high speed and also a response of a low current speed by operating a 1st phasing auxiliary drive circuit when a power voltage indicating signal shows the 1st operating voltage and then operating again the 1st phasing auxiliary drive circuit with a prescribed delay after an input logical signal is changed to the 2nd logical value from the 1st logical value when the power voltage indicating signal shows the 2nd operating voltage. SOLUTION: The source-drain path of a 1st phasing auxiliary drive transistor TR N508 is connected between a 1st auxiliary drive node 516 and the VSS voltage. The TR N508 can be conceptualized as a 1st phasing auxiliary drive element since the operating potential is fixed at the node 516. Thereby a 1st standard auxiliary drive TR N500 and the TR N508 are activated in a low voltage mode. In a high voltage mode, however, the TR N508 is activated after the TR N500 is activated.