Redundancy circuit for memory array and method for disabling non-redundant wordlines and for enabling redundant wordlines

1. A redundancy circuit for a memory array comprising:

a miscompare detector for comparing a current address to be accessed with a memory defect address; said miscompare detector providing an enable redundant wordline signal responsive to a match of the compared addresses; said miscompare detector including a plurality of compare field effect transistors coupled between a common precharge node and a common discharge node;

a deactivate driver circuit coupled to said miscompare detector for disabling non-redundant wordlines responsive to said enable redundant wordline signal; and

a redundant driver coupled to said miscompare detector for enabling redundant wordlines responsive to said enable redundant wordline signal.

2. A redundancy circuit for a memory array as recited in claim 1 includes a wordline select circuit coupled to said redundant driver for selecting a redundant wordline responsive to said enable redundant wordline signal.

3. A redundancy circuit for a memory array as recited in claim 1 wherein said miscompare detector includes a precharge circuit coupled between a supply voltage and said common precharge node and a discharge device coupled between said common discharge node and ground.

4. A redundancy circuit for a memory array as recited in claim 3 wherein one of said plurality of compare field effect transistors is activated, said common precharge node is discharged to identify a miscompare of the compared addresses and an access to a non-redundant wordline is allowed.

5. A redundancy circuit for a memory array as recited in claim 1 wherein said match of the compared addresses is identified by said plurality of compare transistors being deactivated, said common precharge node is maintained in a precharge state.

6. A redundancy circuit for a memory array as recited in claim 1 includes for each redundant wordline a miscompare detector for a wordline read address and a miscompare detector for a word line write address.

7. A redundancy circuit for a memory array as recited in claim 6 wherein said deactivate driver circuit receives a common precharge node signal for each said read address miscompare detector and each said write address miscompare detector.

8. A redundancy circuit for a memory array as recited in claim 1 wherein said deactivate driver circuit generates a reset signal to deactivate a non-redundant wordline decoder responsive to said enable redundant wordline signal.

9. A redundancy circuit for a memory array comprising:

a miscompare detector for comparing a current address to be accessed with a memory defect address; said miscompare detector providing an enable redundant wordline signal responsive to a match of the compared addresses;

a deactivate driver circuit coupled to said miscompare detector for disabling non-redundant wordlines responsive to said enable redundant wordline signal; said deactivate driver circuit including a two-high field effect transistor stack coupled between a reset common node and ground; and

a redundant driver coupled to said miscompare detector for enabling redundant wordlines responsive to said enable redundant wordline signal.

10. A redundancy circuit for a memory array as recited in claim 9 wherein said deactivate driver circuit couples common precharge node signal to said two-high field effect transistor stack to discharge said reset common node responsive to said match and generates a reset signal to deactivate a non-redundant wordline decoder.

11. A redundancy circuit for a memory array as recited in claim 9 wherein said deactivate driver circuit includes a keeper circuit coupled to said reset common node.

12. A redundancy circuit for a memory array as recited in claim 9 wherein said deactivate driver circuit includes a saver transistor coupled to said reset common node; said saver transistor being constantly activated and said saver transistor providing said reset common node in a precharged state when said deactivate driver circuit is activated.

13. A redundancy circuit for a memory array as recited in claim 9 wherein said redundant driver coupled to said miscompare detector for enabling redundant wordlines responsive to said enable redundant wordline signal includes a buffer circuit receiving said enable redundant wordline signal and providing a buffered enable redundant wordline signal output.

14. A redundancy circuit for a memory array as recited in claim 2 wherein said wordline select circuit coupled to said redundant driver for selecting a redundant wordline responsive to said enable redundant wordline signal includes a wordline select circuit for a wordline read address and a wordline select circuit for a wordline write address; said wordline select circuit for said wordline read address and said wordline select circuit for said wordline write address coupled to said deactivate driver circuit.

15. A redundancy circuit for a memory array as recited in claim 14 wherein said wordline select circuit for said wordline write address includes a dynamic write node and said wordline select circuit for said wordline read address includes a dynamic read node; said dynamic write node and said dynamic read node being precharged responsive to a clock output signal generated by said deactivate driver circuit.

16. A redundancy circuit for a memory array as recited in claim 14 wherein said wordline select circuit for said wordline write address receives a write clock signal and said enable redundant wordline signal and said wordline select circuit for said wordline read address receives a read clock signal and said enable redundant wordline signal.

17. A method for disabling non-redundant wordlines and for enabling redundant wordlines using a redundancy circuit for a memory array comprising the steps of:

providing a miscompare detector having a plurality of compare field effect transistors coupled between a common precharge node and a common discharge node for comparing a current address to be accessed with a memory defect address;

said miscompare detector providing an enable redundant wordline signal responsive to a match of the compared addresses;

providing a deactivate driver circuit coupled to said miscompare detector, responsive to said enable redundant wordline signal, for generating a reset signal for disabling non-redundant wordlines; and

providing a redundant driver coupled to said miscompare detector, responsive to said enable redundant wordline signal, for activating a redundant wordline for said memory defect address.

18. A method for disabling non-redundant wordlines and for enabling redundant wordlines as recited in claim 17 wherein said generated reset signal deactivates a wordline decoder for the memory array.

19. A method for disabling non-redundant wordlines and for enabling redundant wordlines as recited in claim 18 includes the step responsive to a miscompare of the compared addresses, of allowing a normal access to a non-redundant wordline.