IP Library Granted Patent US 12,130,656
Granted Patent B1
US 12,130,656 · App. 18/343,841 · Granted Oct 29, 2024

Skew-correcting clock buffer

Inventors: Gavin Allen (Greenwood, AU); Ian Dedic (London, GB); Bo Yang (Sunnyvale, CA); Taran Gupta (Santa Clara, CA)
Assignee: ACACIA COMMUNICATIONS, INC.
G06F1/10H03K3/037
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Quick Facts
Patent No.
US 12,130,656
App. No.
18/343,841
Granted
Oct 29, 2024
Kind
B1
Abstract

A method system, and apparatus for adjusting skew in a circuit comprising feeding an input clock into a first push-pull source follower stage, feeding an inverse of an input clock bar into a first CMOS inverter stage, creating an output clock based on an equal contribution of the input clock of the first push-pull follower stage and the inverse of the input clock bar of the first CMOS invert stage, feeding the input clock bar into a first push-pull source follower stage, feeding an inverse of the input clock into a first CMOS inverter stage, and creating an output clock based on an equal contribution of the input clock bar of the first push-pull follower stage and the inverse of the input clock bar of the first CMOS invert stage.

Claims (36)

1. An apparatus comprising:

a Complementary Metal Oxide Semiconductor (CMOS) inverter stage;

a non-inverting push-pull source follower stage paired with the CMOS inverter stage;

a clock bar signal coupled to the non-inverting push-pull source follower stage; and

an inverse of a clock signal coupled to the CMOS inverter stage to form a clock bar out signal, wherein the clock bar signal and the inverse of the clock signal contribute equally to forming the clock bar out signal.

2. The apparatus of claim 1 , wherein the non-inverting push-pull source follower stage adjusts a skew of the clock bar signal based on a bias current in the non-inverting push-pull source follower stage.

3. The apparatus of claim 1 , wherein the CMOS inverter stage comprises a switched capacitor.

4. The apparatus of claim 3 , wherein the switched capacitor injects skew into the clock bar out signal based on a value of the switched capacitor.

5. The apparatus of claim 3 , further comprising an analog feedback loop to adjust a setting of the switched capacitor to remove clock skew.

6. The apparatus of claim 3 , further comprising a digital feedback loop to adjust a setting of the switched capacitor to remove clock skew.

7. The apparatus of claim 3 , further comprising software instructions to adjust a setting of the switched capacitor to remove clock skew.

8. An apparatus comprising:

a Complementary Metal Oxide Semiconductor (CMOS) inverter stage;

a non-inverting push-pull source follower stage paired with the CMOS inverter stage;

a clock signal coupled to the non-inverting push-pull source follower stage; and

an inverse of a clock bar signal coupled to the CMOS inverter stage to form a clock out signal, wherein the clock signal and the inverse of the clock bar signal contribute equally to forming the clock out signal.

9. The apparatus of claim 8 , wherein the non-inverting push-pull source follower stage adjusts a skew of the clock signal based on a bias current in the non-inverting push-pull source follower stage.

10. The apparatus of claim 8 , wherein the CMOS inverter stage comprises a switched capacitor.

11. The apparatus of claim 10 , wherein the switched capacitor injects skew into the clock out signal based on a value of the switched capacitor.

12. The apparatus of claim 10 , further comprising an analog feedback loop to adjust a setting of the switched capacitor to remove clock skew.

13. The apparatus of claim 10 , further comprising a digital feedback loop to adjust a setting of the switched capacitor to remove clock skew.

14. The apparatus of claim 10 , further comprising software instructions to adjust a setting of the switched capacitor to remove clock skew.

15. An apparatus comprising:

a first Complementary Metal Oxide Semiconductor (CMOS) inverter stage;

a first non-inverting push-pull source follower stage paired with the first CMOS inverter stage;

a clock bar signal coupled to the first non-inverting push-pull source follower stage;

an inverse of a clock signal coupled to the first CMOS inverter stage to form a clock bar out signal;

a second Complementary Metal Oxide Semiconductor (CMOS) inverter stage;

a second non-inverting push-pull source follower stage paired with the second CMOS inverter stage;

a second clock signal coupled to the second non-inverting push-pull source follower stage; and

an inverse of a clock bar signal coupled to the second CMOS inverter stage to combine to form a clock out signal.

16. The apparatus of claim 15 , wherein the first non-inverting push-pull source follower stage adjusts a skew of the clock bar signal based on a bias current in the first non-inverting push-pull source follower stage; and wherein the second non-inverting push-pull source follower stage adjusts the skew of the clock signal based on a bias current in the second non-inverting push-pull source follower stage.

17. The apparatus of claim 15 , wherein the first CMOS inverter stage comprises a first switched capacitor and wherein the second CMOS inverter stage comprises a second switched capacitor.

18. The apparatus of claim 17 , wherein the first switched capacitor injects skew into the clock bar out signal based on a value of the first switched capacitor.

19. The apparatus of claim 17 , wherein the second switched capacitor injects skew into the clock out signal based on a value of the second switched capacitor.

20. The apparatus of claim 17 , further comprising at least one of an analog feedback loop, a digital feedback loop, or software instructions, wherein at least one of the analog feedback loop, the digital feedback loop, or the software instructions is enabled to adjust a setting of the first switched capacitor; and wherein the at least one of the analog feedback loop, the digital feedback loop, or the software instructions is enabled to adjust a setting of the second switched capacitor to account for clock skew occurring in later circuits.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 19, 2024
From: ACACIA COMMUNICATIONS, INC.
To: ACACIA TECHNOLOGY, INC.
Reel/Frame 066832/0659 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 8, 2024
From: ALLEN, GAVIN; DEDIC, IAN; YANG, BO; GUPTA, TARUN
To: ACACIA COMMUNICATIONS, INC.
Reel/Frame 066048/0344 →
Continuity (3)
Continuation 17833306 · Jun 6, 2022
Continuation 17179229 · Feb 18, 2021
Provisional Application 62979275 · Feb 20, 2020