US 5,629,947 A · Method and apparatus for detecting positive and negative runt pulses simultaneously

Abstract

The present invention comprises a runt fault detector which detects positive and negative runt faults based only upon the crossings of a high voltage threshold and a low voltage threshold. Specifically, the runt fault detector detects a positive runt fault when an input signal transitions from below to above the low voltage threshold and then back below the low voltage threshold without first transitioning from below to above the high voltage threshold. The runt fault detector also detects a negative runt fault when an input signal transitions from above to below the high voltage threshold and then back above the high voltage threshold without first transitioning from above to below the low voltage threshold. Simultaneous detection of both positive and negative runt faults may also be achieved by the present invention.

Claims19

Dependent claims

A runt fault detector comprising:

a threshold comparator responsive to an input signal, a first voltage threshold and a second voltage threshold, which produces a first transition signal when the input signal transitions across the first voltage threshold in a first direction away from the second voltage threshold, and a second transition signal when the input signal transitions across the second voltage threshold in a second direction opposite the first direction;
a full transition detector responsive to the first transition signal and the second transition signal which produces a first full-transition signal upon detection of a full transition by the input signal across the second voltage threshold and then the first voltage threshold in sequence in the first direction;
and
a runt detector responsive to the first full-transition signal and the first transition signal to generate a runt fault upon detection in sequence of the first full-transition signal and then the first transition signal without an intervening detection of the second transition signal.

1 more element

A method for detecting a runt fault on an input signal based solely upon transitions by the input signal across a first voltage threshold and across a second voltage threshold, comprising the steps of:

(a) monitoring the input signal to produce a first full-transition signal upon detection in sequence of a transition by the input signal across the second voltage threshold in a first direction towards the first voltage threshold and then across the first voltage threshold in the first direction;
(b) monitoring the input signal to produce:
(i) a first transition signal upon detection of a transition by the input signal across the first voltage threshold in the first direction, and
(ii) to produce a second transition signal upon detection of a transition by the input signal across the second voltage threshold in a second direction opposite from the first direction;
and
(c) monitoring the first full-transition signal and the first transition signal to produce a runt fault upon detection in sequence of the first full-transition signal and then the first transition signal without an intervening detection of the second transition signal.

3 more elements

(a) monitoring the input signal to produce a first full-transition signal upon detection in sequence of a transition by the input signal across the second voltage threshold in a first direction towards the first voltage threshold and then across the first voltage threshold in the first direction, and then across the first voltage threshold in a second direction opposite the first direction;
(b) monitoring the input signal:
(i) to produce a first transition signal upon detection of a transition by the input signal across the first voltage threshold in the first direction, and
(ii) to produce a second transition signal upon detection of a transition by the input signal across the second voltage threshold in the second direction;
and
(c) monitoring the first full-transition signal and the first transition signal to produce a runt fault upon detection in sequence of the first full-transition signal and then the first transition signal without an intervening detection of the second transition signal.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for detecting positive and negative runt pulses simultaneously

Life of this patent

Method and apparatus for detecting positive and negative runt pulses simultaneously

Life of this patent

Abstract

Claims19