High-speed and low-noise output buffer
AssigneeHyundai Electronics Industries CP., Ltd.
InventorsGeun Young Park, Kwang Sup Shin
Life of this patent
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Abstract
The disclosure is an output buffer capable of preventing a noise by reducing a gradient value of input voltage of an input terminal using a detector which selectively operates only under high supply voltage to reduce a peak value of the current through the pull-up and pull-down transistors of the output buffer, and also capable of achieving an output depending upon the speed by using the conventional circuit under supply voltage less than rated voltage.
Claims9
An output buffer of a semiconductor memory device having a pull-up transistor inputting an output value from a sense amplifier at its gate terminals to pull up an output terminal and a pull-down transistor pulling down said output terminal, comprising:
- first reducing means for reducing a voltage gradient of a pull-up transistor by temporarily charging voltage of the gate terminal of said pull-up transistor when an unstable high voltage is applied from an external supply voltage unit and the output value of said sense amplifier is changed from a logic "high" level" to a logic "low" level;
- second reducing means for reducing a voltage gradient of a gate terminal of a pull-down transistor by temporarily discharging voltage of the gate terminal of said pull-down transistor when an unstable high voltage is applied from an external supply voltage unit and the output value of said sense amplifier is changed from a logic "low" level to a logic "high" level;
- first voltage generating means connected to said first reducing means to output a given voltage by which said first reducing means is off to said first reducing means when a stable low voltage is applied from the external supply voltage unit;
- and
- second voltage generating means connected to said second reducing means to output a given voltage by which said second reducing means is off to said second reducing means when a stable low voltage is applied from the external supply voltage unit.
Dependencies are inferred from the claim text.