Configurable IC's with large carry chains

• US 20070244960A1
• Filed: 03/15/2005
• Published: 10/18/2007
• Est. Priority Date: 11/08/2004
• Status: Active Grant

• Current Assignee: Altera Corporation (Intel Corporation)
• Original Assignee: Tabula Incorporated
• Inventors: Redgrave, Jason, Schmit, Herman
• Granted Patent: US 7,743,085 B2
• Time in Patent Office: Days
• US Class Current: 708/700
• CPC Class Codes: G06F 2207/3868 Bypass control, i.e. possibility to transfer an operand unchanged to the output
• CPC Class Codes: G06F 7/506 with simultaneous carry generation for, or propagation over, two or more stages
• CPC Class Codes: H03K 19/173 using elementary logic circuits as components

Abstract

Some embodiments provide a configurable IC that includes several configurable logic circuits, where the logic circuits include several sets of associated configurable logic circuits. For each several sets of associated configurable logic circuits, the reconfigurable IC also includes a carry circuit for performing up to N carry operations sequentially, wherein N is greater than two.

Claims

1. A configurable IC comprising:

a) a plurality of configurable logic circuits, wherein the logic circuits include a plurality of sets of associated configurable logic circuits; and

b) for each of a plurality of sets of associated configurable logic circuits, a carry circuit for performing up to N carry operations sequentially, wherein N is greater than two.

2. The configurable IC of claim 1, wherein each carry operation is a one-bit carry operation associated with a one-bit add or subtract operation.

3. The configurable IC of claim 1, wherein each set of associated configurable logic circuits includes N configurable logic circuits for performing an N-bit add or subtract operation.

4. The configurable IC of claim 3, wherein each set of N configurable logic circuits are also for performing operations unrelated to add and subtract operations.

5. The configurable IC of claim 4, wherein to perform any operation, each configurable logic circuit receives a configuration data set that configures the logic circuit to perform the operation.

6. The configurable IC of claim 3, wherein the carry circuit for a set of N configurable logic circuits is one shared circuit that performs a carry chain operation for all N configurable logic circuits.

7. The configurable IC of claim 3, wherein the carry circuit receives propagate and generate signals from each of the N configurable logic circuits that performs an add or subtract operation, and based on the propagate and generate signals generates carry signals.

8. The configurable IC of claim 3, wherein the N configurable logic circuits are positioned next to each other in the configurable IC.

9. The configurable IC of claim 8, wherein the N configurable logic circuits also are placed around the carry circuit to increase the speed of the carry operation.

10. The configurable IC of claim 1, wherein the IC comprises at least 1000 configurable logic circuits and at least 250 carry circuits.

11. The configurable IC of claim 3, wherein the carry circuit is a carry chain formed by serially connecting a set of one-bit carry circuits.

12. The configurable IC of claim 11, wherein the carry chain is a Manchester carry chain.

13. A electronic device comprising:

a configurable integrated circuit (“

IC”

) comprising;

a) a plurality of configurable logic circuits, wherein the logic circuits include a plurality of sets of associated configurable logic circuits; and

b) for each of a plurality of sets of associated configurable logic circuits, a carry circuit for performing up to N carry operations sequentially, wherein N is greater than two.

14. The electronic device of claim 13, wherein each carry operation is a one-bit carry operation associated with a one-bit add or subtract operation.

15. The electronic device of claim 13, wherein each set of associated configurable logic circuits includes N configurable logic circuits for performing an N-bit add or subtract operation.

16. The electronic device of claim 15, wherein the carry circuit for a set of N configurable logic circuits is one shared circuit that performs a carry chain operation for all N configurable logic circuits.

17. The electronic device of claim 15, wherein the carry circuit receives propagate and generate signals from each of the N configurable logic circuits that performs an add or subtract operation, and based the propagate and generate signals generates carry signals.

18. The electronic device of claim 15, wherein the N configurable logic circuits are positioned next to each other in the configurable IC, wherein the N configurable logic circuits also are placed around the carry circuit to increase the speed of the carry operation.

19. The electronic device of claim 13, wherein the IC comprises at least 1000 configurable logic circuits and at least 250 carry circuits.

20. The electronic device of claim 15, wherein the carry circuit is a carry chain formed by serially connecting a set of one-bit carry circuits.