Adaptive keeper sizing for dynamic circuits based on fused process corner data

• US 20040051561A1
• Filed: 09/17/2002
• Published: 03/18/2004
• Est. Priority Date: 09/17/2002
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Gauthier, Claude R., Desai, Shaishav A.
• Granted Patent: US 6,914,452 B2
• Time in Patent Office: Days
• US Class Current: 326/98
• CPC Class Codes: H03K 19/0963 using transistors of complementary type H03K19/0966 takes precedence

Abstract

An invention is provided for an adaptive keeper circuit. The adaptive keeper circuit includes a first keeper transistor having a first terminal in electrical communication with a power supply and a second terminal in electrical communication with an internal dynamic node. In addition, a second keeper transistor is included that is configured in parallel to the first keeper transistor. The second keeper transistor also has a first terminal in electrical communication with the power supply. The second keeper transistor can be added to the first keeper transistor using a feedback bit line, which is configured to control current flow between the second keeper transistor and the internal dynamic node based on a state of the feedback bit line. The state of the feedback bit line is based on a process corner characteristic of the die. Additional keeper transistors and corresponding feedback bit lines can be added to the keeper circuit to increase flexibility.

Claims

1. An adaptive keeper circuit, comprising:

a first keeper transistor having a first terminal in electrical communication with a power supply and a second terminal in electrical communication with an internal dynamic node;

a second keeper transistor configured in parallel to the first keeper transistor, the second keeper transistor having a first terminal in electrical communication with the power supply; and

a feedback bit line configured to control current flow between the second keeper transistor and the internal dynamic node based on a state of the feedback bit line, the state of the feedback bit line being based on a process corner characteristic of the die.

2. An adaptive keeper circuit as recited in claim 1, further comprising a feedback transistor having a first terminal in electrical communication with the second keeper transistor, a second terminal in electrical communication with the internal dynamic node, and a gate coupled to the feedback bit line.

3. An adaptive keeper circuit as recited in claim 2, wherein the feedback transistor controls current flow between the second keeper transistor and the internal dynamic node based on a state of the feedback bit line.

4. An adaptive keeper circuit as recited in claim 1, further comprising a plurality of incremental keeper transistors, each incremental keeper transistor configured in parallel to the first keeper transistor, each incremental keeper transistor having a first terminal in electrical communication with the power supply.

5. An adaptive keeper circuit as recited in claim 4, further comprising a plurality of feedback bit lines each corresponding to a particular incremental keeper transistor of the plurality of incremental transistors, each feedback bit line configured to control current flow between the corresponding incremental keeper transistor and the internal dynamic node based on a state of the feedback bit line.

6. An adaptive keeper circuit as recited in claim 5, wherein the state of each feedback bit line of the plurality of feedback bit lines is based on a process corner characteristic of the die.

7. An adaptive keeper circuit as recited in claim 5, further comprising a plurality of feedback transistors that control current flow between corresponding incremental keeper transistors of the plurality of incremental keeper transistors and the internal dynamic node.

8. An adaptive keeper circuit as recited in claim 7, wherein a gate of each feedback transistor of the plurality of feedback transistors is coupled to a corresponding bit line of the plurality of bit lines.

9. A semiconductor die having adaptive keeper logic, comprising:

a plurality of dynamic circuits, each dynamic circuit including an adaptive keeper circuit capable of being adjusted based on a bit code;

a process corner databank having process corner data that indicates a process corner of the semiconductor die; and

a test processor unit in communication with the process corner databank and the plurality of dynamic circuits, the test processor unit being capable of obtaining process corner data from the process corner databank, the test processor unit further being capable of providing a bit code based on the process corner data to the plurality of dynamic circuits.

10. A semiconductor die as recited in claim 9, wherein the process corner databank is a fuse bank having a plurality of fuses, wherein a configuration of the plurality of fuses indicates a process corner of the semiconductor die.

11. A semiconductor die as recited in claim 10, wherein each adaptive keeper circuit includes at least one feedback bit line that receives a portion of the bit code, the feedback bit line controlling current flow to an internal dynamic node.

12. A semiconductor die as recited in claim 11, wherein each adaptive keeper circuit further includes a first keeper transistor and at least one secondary keeper transistor in parallel with the first keeper transistor, the first keeper transistor and the secondary keeper transistor being in electrical communication with a power supply, the first keeper transistor further being in electrical communication with an internal dynamic node.

13. A semiconductor die as recited in claim 12, wherein each adaptive keeper circuit further includes at least one feedback transistor in electrical communication with the at least one secondary transistor, the feedback transistor controlling current flow between the secondary transistor and the internal dynamic node.

14. A semiconductor die as recited in claim 13, wherein the at least one feedback transistor controls current flow between the secondary transistor and the internal dynamic node based on a state of the feedback bit line.

15. A semiconductor die as recited in claim 9, wherein the test processor unit translates the process corner data into the bit code using a lookup function.

16. A semiconductor die as recited in claim 9, further comprising a lookup processor that receives process corner data from the test processor unit and provides a corresponding bit code to the test processor unit based on the received process corner data.

17. A method for optimizing a keeper circuit for use in a dynamic circuit, comprising the operations of:

obtaining process corner data for a die from a databank present on the die;

translating the process corner data into a bit code, the bit code indicating a process corner of the die; and

adding particular secondary keeper transistors to a first keeper transistor, the particular secondary keeper transistors being selected using the bit code.

18. A method as recited in claim 17, wherein secondary keeper transistors are added to the first keeper transistor utilizing corresponding feedback transistors, each feedback transistor having a gate coupled to a bit of the bit code.

19. A method as recited in claim 18, wherein the databank is an electrical fuse bank comprising a plurality of fuses, the process corner data being represented by a particular fuse configuration of the plurality of fuses.

20. A method as recited in claim 19, wherein each secondary keeper transistor provides current to an internal dynamic node based on a state of the bit code.