Patent ID: 6175598
Filing Date: 2001-01-16
Classification: H03K

Abstract:
An output noise control circuit with significantly reduced power/ground bounce characteristics when multiple outputs thereof are being simultaneously switched, said control circuit comprising in combination:a plurality of output buffers, each being formed of an output driver stage, a first pre-driver stage, and a second pre-driver stage;each of said output driver stages including a pull-up drive transistor and a pull-down drive transistor;said pull-up drive transistor having one of its main electrodes connected to a power supply potential node, its other one of its main electrodes connected to an output node, and its gate connected to receive a first control signal for generating a low-to-high transition at the output node;said pull-down transistor having one of its main electrodes connected to the output node, its other one of its main electrodes connected to a ground potential node, and its gate connected to receive a second control signal for generating a high-to-low transition at the output node;each said first pre-driver stage including a first inverter having its input connected to receive a corresponding one of input drive signals and its output connected to the gate electrode of said pull-up drive transistor;a shared pull-up resistor having its one end coupled to each of said first pre-driver stage inverters and its other end connected to the ground potential node;each said second pre-driver stage including a second inverter having its input connected to receive said corresponding one of the input drive signals and its output connected to the gate electrode of said pull-down drive transistor; anda shared pull-down resistor having its one end coupled to each of said second pre-driver stage inverters and its other end connected to the power supply potential node.