HIGH SPEES LOW POWER OF OUTPUT BUFFER FOR SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

PURPOSE: An output buffer is provided to minimize ringing and make faster a signal transfer time by feedbacking an output state of a final output terminal in an output buffer to use an input signal controlling the final output terminal and then step-by-step adjusting the buffer of the output terminal. CONSTITUTION: An output buffer includes a pull-up transistor(Q1) and a pull-down transistor(Q2) serially connected between a supply power terminal(Vcc) and a ground(Vss). An output terminal(OUT) of the output buffer is connected to a common connection terminal of the pull-up transistor and the pull-down transistor. An input terminal(INP) of the output buffer is connected to input terminals at one side of a NAND gate and NOR gate, respectively. An output of the NAND gate is connected to a gate of the pull-up transistor. An output of the NOR gate is connected to a gate of the pull-down transistor. A feedback unit(10) feedbacks an output of the output terminal to the NAND gate and the NOR gate, respectively. A pull-up output maintaining unit(20) continuously maintains the value of the pull-up transistor at the output terminal by means of an input signal at the previous stage even when any input to the input terminal does not exist. A pull-down output maintaining unit(30) continuously maintains the value of the pull-down transistor at the output terminal by means of an input signal at the previous stage even when any input to the input terminal does not exist. A controller(40) controls an input of the input terminal to control the operation of the buffer.