Imbalanced sense amplifier fuse detection circuit

• US 6,426,668 B1
• Filed: 03/22/2001
• Issued: 07/30/2002
• Est. Priority Date: 03/22/2001
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Phan, John T., Morrish, J. R.
• Primary Examiner(s): TON, MY TRANG
• Application Number:
  US09/814,574
• Time in Patent Office: 495 Days
• Field of Search: 327/51, 327/55, 327/56, 327/57, 327/215, 327/219, 327/525, 327/562
• US Class Current: 327/525
• CPC Class Codes: G11C 17/18 Auxiliary circuits, e.g. for writing into memory

Abstract

A method and structure to provide a circuit adapted to sense the status of a fuse includes an imbalanced sense amplifier latch which includes first and second nodes connected to the fuse. The first node is connected to a fuse and is weaker than the second node, allowing the first node to sense a different voltage level. The voltage difference between the nodes indicates the conductive status of the fuse.

Claims

1. A circuit adapted to sense a status of a fuse comprising:

an imbalanced sense amplifier latch operatively connected to said fuse, said imbalanced sense amplifier latch including a first portion and a second portion, and

a first transistor between said fuse and said imbalanced sense amplifier latch and a second transistor between said imbalanced sense amplifier and ground,

wherein said first portion is operatively connected to said fuse and is weaker than said second portion such that said first portion senses a different voltage level than said second portion, and

wherein a delay between activation of said first transistor and said second transistor controls a sensing resistance threshold of said circuit; and

further

wherein a voltage difference between said first portion and said second portion indicates a conductive status of said fuse.

2. The circuit in claim 1, wherein said first portion includes first devices having first gate sizes smaller than that of second devices in said second portion.

3. The circuit in claim 1, further comprising precharge devices connected to said imbalanced sense amplifier latch.

4. The circuit in claim 1, wherein a different amount of current flows through said first portion than said second portion.

5. The circuit in claim 1, wherein said fuse has an open circuit in a blown state.

6. The circuit in claim 1, wherein said fuse has a short circuit in a blown state.

7. A circuit adapted to sense a status of a fuse comprising:

all imbalanced sense amplifier latch operatively connected to said fuse, said imbalanced sense amplifier latch including a first portion and a second portion, and

a first transistor between said fuse and said imbalanced sense amplifier latch and a second transistor between said imbalanced sense amplifier and ground,

wherein a delay between activation of said first transistor and said second transistor controls a sensing resistance threshold of said circuit; and

further

wherein a voltage difference between said first portion and said second portion is latched by said imbalanced sense amplifier and indicates a conductive status of said fuse.

8. The circuit in claim 7, wherein said first portion is operatively connected to said fuse and is weaker than said second portion such that said first portion senses a lower voltage that said second portion.

9. The circuit in claim 7, wherein said first portion includes first devices having first gate sizes smaller than that of second devices in said second portion.

10. The circuit in claim 7, further comprising precharge devices connected to said imbalanced sense amplifier latch.

11. The circuit in claim 7, wherein a different amount of current flows through said first portion than said second portion.

12. A circuit adapted to sense a status of a fuse comprising:

an imbalanced sense amplifier latch operatively connected to said fuse, said imbalanced sense amplifier latch including a first portion and a second portion, and

a first transistor between said fuse and said imbalanced sense amplifier latch and a second transistor between said imbalanced sense amplifier and ground,

wherein a delay between activation of said first transistor and said second transistor controls a sensing resistance threshold of said circuit; and

further

wherein a voltage difference between said first portion and said second portion indicates a conductive status of said fuse.

13. The circuit in claim 12, further comprising a voltage source operatively connected to said fuse and said imbalanced sense amplifier.

14. The circuit in claim 12, wherein said first portion is operatively connected to said fuse and is weaker than said second portion such that said first portion senses a lower voltage that said second portion.

15. The circuit in claim 12, wherein said first portion includes first devices having first gate sizes smaller than that of second devices in said second portion.

16. The circuit in claim 12, further comprising precharge devices connected to said imbalanced sense amplifier latch.

17. The circuit in claim 12, wherein a different amount of current flows through said first portion than said second portion.