Redundancy control circuit employed with various digital logic systems including shift registers
First Claim
1. A redundancy circuit comprising:
- a first circuit element;
a second circuit element; and
a redundancy control circuit for disabling one of the first and second circuit elements comprising;
a severable fuse link having first and second terminals;
means for receiving a momentary signal;
a control circuit having an input and first and second output terminals;
the second terminal of the severable fuse link being coupled to the control circuit input; and
means connected to the second terminal of the severable fuse link responsive to the fuse link being intact for placing the first output terminal of the control circuit in a first state and the second output terminal of the control circuit in a second state and jointly responsive to a momentary signal applied to the receiving means and the fuse link being severed for placing the first output terminal of the control circuit in the second state and the second output terminal of the control circuit in the first state; and
the first output terminal of the control circuit being coupled to the first circuit element and the second output terminal of the control circuit being coupled to the second circuit element.
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Accused Products
Abstract
A redundancy circuit that substitutes a redundant circuit element for a corresponding defective circuit element includes a severable fuse link and a redundancy control circuit with an input connected to the severable fuse link and first and second outputs. When the fuse link is intact, the first output of the redundancy control circuit is in a first state and the second output is in a second state. When the fuse link is severed, a momentary signal on power up places the first output in the second state and the second output in the first state. The first output is coupled to the one circuit element and the second output is coupled to the corresponding redundant circuit element. If the one circuit element is defective, it is disabled by severing the fuse link.
32 Citations
22 Claims
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1. A redundancy circuit comprising:
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a first circuit element; a second circuit element; and a redundancy control circuit for disabling one of the first and second circuit elements comprising; a severable fuse link having first and second terminals; means for receiving a momentary signal; a control circuit having an input and first and second output terminals; the second terminal of the severable fuse link being coupled to the control circuit input; and means connected to the second terminal of the severable fuse link responsive to the fuse link being intact for placing the first output terminal of the control circuit in a first state and the second output terminal of the control circuit in a second state and jointly responsive to a momentary signal applied to the receiving means and the fuse link being severed for placing the first output terminal of the control circuit in the second state and the second output terminal of the control circuit in the first state; and the first output terminal of the control circuit being coupled to the first circuit element and the second output terminal of the control circuit being coupled to the second circuit element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Redundancy control circuitry comprising:
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first and second circuit elements; a severable fuse link; the redundancy control circuitry having an input terminal for receiving a monetary signal, a first output terminal coupled to the first circuit element, a second output terminal coupled to the second circuit element, and being adapted to disable one of the first and second circuit elements when the fuse link in intact and being adapted to disable the other of the first and second circuit elements when the fuse link is severed; first and second inverters each having an input and an output; means coupled to the redundancy control circuit input terminal for selectively coupling the output of the second inverter to the input of the first inverter; the output of the first inverter being coupled to the input of the second inverter and to the first output terminal of the redundancy control circuitry; the output of the second inverter being coupled to the second output terminal of the redundancy control circuitry; and a semiconductor switching means having an output electrode coupled to the fuse link and to the input of the first inverter, and having a control electrode coupled to the input terminal of the redundancy control circuitry. - View Dependent Claims (11, 12, 13, 14)
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15. Redundant shift register circuitry comprising:
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first and second shift registers with each having at least first and second stages and with each stage having an input and an output; a first pair of first and second coupling control circuits and a second pair of third and fourth coupling circuits with each of the coupling circuits having an input terminal, an output terminal and a control terminal; the output of the first stage of the first shift register being coupled to the inputs of the first and second coupling control circuits; the output of the first stage of the second shift register being coupled to the inputs of the third and fourth coupling control circuits; the output terminals of the first and third coupling control circuits being coupled to the input of the second stage of the first shift register; the output terminals of the second and fourth coupling control circuits being coupled to the input of the second stage of the second shift register; a severable fuse link; redundancy control circuitry having an input terminal for receiving a monetary signal, a first output terminal coupled to the control terminals of the first and second coupling control circuits, and a second output terminal coupled to the control terminals of the third and fourth coupling control circuits; the redundancy control circuitry being adapted to disable one of the first and second pairs of coupling control circuits when the fuse link in intact and being adapted to disable the other pair of coupling control circuits when the fuse link is severed; the redundancy control circuitry comprising; first and second inverters each having an input and an output; means coupled to the redundancy control circuit input terminal for selectively coupling the output of the second inverter to the input of the first inverter; the output of the first inverter being coupled to the input of the second inverter and to the first output terminal of the redundancy control circuitry; the output of the second inverter being coupled to the second output terminal of the redundancy control circuitry; and a semiconductor switching means having an output electrode coupled to the fuse link and to the input of the first inverter, and having a control electrode coupled to the input terminal of the redundancy control circuitry. - View Dependent Claims (16, 17, 18, 19)
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20. Redundancy circuitry comprising:
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a severable fuse link; the redundancy circuitry having an input and first and second outputs with the first output being connectable to a first circuit element and the second output being connectable to a second circuit element; the first and second circuit elements being essentially identical and each being adapted to be enabled by a first logic level and disabled by a second logic level; a first control circuit having an input coupled to the input of the redundancy circuitry and having an output; a second control circuit having first and second inputs and first and second outputs; the first input of the second control circuit being coupled to the redundancy circuitry input terminal; the second input of the second control circuit being coupled to the severable fuse link and to the output of the first control circuit; the first and second outputs of the second control circuit being coupled to the first and second redundancy circuitry outputs, respectively; the first control circuit being adapted upon receipt of a control signal applied to the input thereof to generate at the output thereof a first logic level when the severable fuse link is intact and to generate at the output thereof a second logic level when the severable link fuse is severed; and the second control circuit being adapted to generate a first set of complementary logic levels at the first and second redundancy circuitry output terminals upon receipt of the first logic level from the first control circuit and to generate a second set of complementary logic levels on the first and second outputs of the redundancy circuitry which are opposite to the first set of complementary logic levels. - View Dependent Claims (21, 22)
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Specification