US 5,495,186 AGranted

Differential type MOS transmission circuit

AssigneesHitachi, Ltd., Hitachi Communication Systems, Inc.

InventorsNobuaki Kanazawa, Masao Mizukami, Kunihiro Ito

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Abstract

A differential type MOS transmission circuit includes a signal driving circuit and a signal receiving circuit to realize high speed transmission for a short distance transmission between different LSIs, etc. A pair of transmission lines between the signal driving circuit and the signal receiving circuit are driven by a pair of drivers in the signal driving circuit so as to take either one of three states, i.e. one state where both of the lines are in a precharged states and two states where either one of the lines is in a discharged state. A signal driving circuit includes signal generating circuits generating variations in control signals varying pulse-like in response to rise and fall of an input signal to thereby obtain the discharge state. The signal receiving circuit generates an output signal depending on the state of the transmission lines and is constructed of a Schmitt trigger circuit with a hysteresis characteristic, for which an input threshold voltage for output logical values has a level smaller than a potential difference between the precharged level and the discharged level.

Claims10

Dependent claims

A differential type MOS digital transmission circuit comprising:

at least a signal driving circuit including,
signal generating circuits generating a first control signal varying pulse-like based on a transition of an input signal of two logical values, from a first logical value to a second logical value and a second control signal varying pulse-like based on a transition of said input signal from said second logical value to said first logical value,
a first driver whose output is connected with a first transmission line of a pair of first and second transmission lines and which discharges said corresponding first transmission line during a period of pulse-like variation of said first control signal and precharges said corresponding first transmission line during the other period, and
a second driver whose output is connected with said second transmission line and which discharges said corresponding second transmission line during a period of pulse-like variation of said second control signal and precharges said corresponding second transmission line during the other period,
thereby generating a precharged state of both said transmission lines and a discharged state of either one of said transmission lines;
and
a Schmitt trigger type signal receiving circuit (UBR) provided in pair with said at least a signal driving circuit and including an output generating circuit whose input is connected with said pair of transmission lines and which amplifies in a differential manner a potential difference between said pair of transmission lines formed by discharge of either one of said transmission lines to generate an output signal of two logical values, and said output generating circuit having a positive feedback circuit of the output signal to provide an input threshold voltage with respect to said two logical values which has a hysteresis characteristic of a level lower than a voltage difference between said precharged level and said discharged level.

4 more elements

A differential type MOS transmission circuit comprising:

at least a signal driving circuit including;
signal generating circuits for generating a first control signal varying pulse-like, based on a transition of an input signal indicative of two logical values, from a first logical value to a second logical value and a second control signal varying pulse-like, based on a transition of said input signal from said second logical value to said first logical value;
a first driver whose output is connected with one transmission line set forcedly at a reference potential and which discharges said corresponding one transmission line during a period of pulse-like variation of said first control signal and charges said corresponding one transmission line during a period of pulse-like variation of said second control signal;
and
a second driver whose output is connected with the other transmission line set forcedly at said reference potential and which discharges said corresponding other transmission line during a period of pulse-like variation of said second control signal and charges said corresponding other transmission line during a period of pulse-like variation of said first control signal;
thereby forming three states in total, i.e. a state where both said transmission lines are at said reference potential and two states where either one of said transmission lines is at the precharged state and the other is at said discharged state;
and
a Schmitt trigger type signal receiving circuit provided in pair with said at least a signal driving circuit and having inputs connected with said pair of transmission lines and which amplifies in a differential manner a potential difference between said pair of transmission lines to generate an output signal indicative of two logical values, and an input threshold voltage for said two logical values having a hysteresis characteristic with a level, which is lower than a voltage difference between said reference potential and the charged level and in addition lower than a voltage difference between said reference potential and the discharged level, through a positive feedback of said output signal.

5 more elements

Dependencies are inferred from the claim text.