INTEGRATED CIRCUIT HAVING A CLOCK DESKEW CIRCUIT THAT INCLUDES AN INJECTION-LOCKED OSCILLATOR

• US 20120224407A1
• Filed: 01/19/2012
• Published: 09/06/2012
• Est. Priority Date: 03/03/2011
• Status: Active Grant

• Current Assignee: Rambus Inc.
• Original Assignee: Rambus Inc.
• Inventors: Aleksic, Marko, Leibowitz, Brian S.
• Granted Patent: US 8,804,397 B2
• Time in Patent Office: Days
• US Class Current: 365/129
• CPC Class Codes: H03K 2005/00286 Phase shifter, i.e. the delay between the output and input pulse is dependent on the frequency, and such that a phase difference is obtained independent of the frequency
• CPC Class Codes: H03K 5/26 the characteristic being duration, interval, position, frequency, or sequence
• CPC Class Codes: H03L 7/081 provided with an additional controlled phase shifter H03L7/0998 takes precedence
• CPC Class Codes: H03L 7/099 concerning mainly the controlled oscillator of the loop
• CPC Class Codes: H03L 7/0995 the oscillator comprising a ring oscillator
• CPC Class Codes: H03L 7/24 using a reference signal directly applied to the generator

Abstract

Methods and apparatuses featuring an injection-locked oscillator (ILO) are described. In some embodiments, an ILO can have multiple injection points and a free-running frequency that is capable of being adjusted based on a control signal. In some embodiments, each injection point of an ILO can correspond to a phase tuning range. In some embodiments, a circuit can include circuitry to detect a phase boundary between two adjacent phase tuning ranges. In some embodiments, a circuit can use the detected phase boundary to switch between the two adjacent phase tuning ranges.

Claims

1. A circuit, comprising:

a first injection-locked oscillator (ILO) to generate a first output signal based on an input signal, wherein the first ILO has a first free-running frequency that is capable of being adjusted based on a first control signal, wherein the first ILO has multiple phase tuning ranges capable of being selected based on a first select signal;

a second ILO to generate a second output signal based on the input signal, wherein the second ILO has a second free-running frequency that is capable of being adjusted based on a second control signal, wherein the second ILO has multiple phase tuning ranges capable of being selected based on a second select signal; and

circuitry to detect a phase boundary between two adjacent phase tuning ranges using the first and the second output signals, and generate the first and the second control signals, and the first and the second select signals.

2. The circuit of claim 1, wherein the circuitry to detect the phase boundary comprises:

a first demultiplexer to inject the input signal into one or more injection points of the first ILO based on the first select signal, wherein each injection point corresponds to a phase tuning range;

a second demultiplexer to inject the input signal into one or more injection points of a second ILO based on the second select signal, wherein each injection point corresponds to a phase tuning range; and

a phase detector to generate a phase detector output signal that is indicative of a phase difference between the first and the second output signals.

3. The circuit of claim 2, wherein the circuitry to detect the phase boundary further comprises:

selection circuitry to generate the second select signal so that the second demultiplexer injects the input signal into multiple injection points of the second ILO; and

sweeping circuitry to generate the first control signal to sweep the first free-running frequency of the first ILO until the phase detector output signal indicates that the phase difference between the first and the second output signals is substantially equal to a pre-determined value.

4. The circuit of claim 3,

wherein the selection circuitry is capable of generating the first select signal so that the first demultiplexer injects the input signal into multiple injection points of the first ILO;

and

wherein the sweeping circuitry is capable of generating the second control signal to sweep the second free-running frequency of the second ILO until the phase detector output signal indicates that the phase difference between the first and the second output signals is substantially equal to a pre-determined value.

5. The circuit of claim 2, wherein the circuitry to detect the phase boundary further comprises:

selection circuitry to generate the first and the second select signals so that the first demultiplexer injects the input signal into a first injection point of the first ILO and the second demultiplexer injects the input signal into a second injection point of the second ILO, wherein the first and the second injection points correspond to adjacent phase tuning ranges; and

sweeping circuitry to generate the first and the second control signals to concurrently sweep, in opposite directions, the first and the second free-running frequencies until the phase detector output signal indicates that the phase difference between the first and the second output signals is substantially equal to a pre-determined value.

6. The circuit of claim 1, wherein the circuitry to detect the phase boundary generates a third select signal, the circuit further comprising a multiplexer to select, based on the third select signal, one of the first and second output signal as an output signal of the circuit, and wherein the circuitry to detect the phase boundary comprises a phase controller to generate, based on the phase boundary between the two adjacent phase tuning ranges, the first and the second control signals, the first and the second select signals, and the output select signal.

7. The circuit of claim 1, wherein the circuitry to detect the phase boundary generates a third select signal, the circuit further comprising a multiplexer to select, based on the third select signal, one of the first and the second output signal as an output signal of the circuit, wherein the circuitry to detect the phase boundary comprises:

a phase detector to generate a phase detector output signal that is indicative of a phase difference between the first and the second output signals; and

a phase controller to generate, based on received phase information and the phase detector output signal, the first and the second control signals, the first and the second select signals, and the output select signal.

8. The circuit of claim 7, wherein the phase controller is capable of switching between adjacent phase tuning ranges in response to the phase detector output signal indicating that the phase difference between the first and the second output signals is substantially equal to a pre-determined value.

9. A controller device that controls the operation of a memory device, the controller device comprising:

a first injection-locked oscillator (ILO) to generate a first output signal based on an input signal, wherein the first ILO has a first free-running frequency that is capable of being adjusted based on a first control signal, wherein the first ILO has multiple phase tuning ranges capable of being selected based on a first select signal;

a second ILO to generate a second output signal based on the input signal, wherein the second ILO has a second free-running frequency that is capable of being adjusted based on a second control signal, wherein the second ILO has multiple phase tuning ranges capable of being selected based on a second select signal; and

circuitry to detect a phase boundary between two adjacent phase tuning ranges using the first and the second output signals, and generate the first and the second control signals, and the first and the second select signals.

10. The controller device of claim 9, wherein the circuitry to detect the phase boundary comprises:

a first demultiplexer to inject the input signal into one or more injection points of the first ILO based on the first select signal, wherein each injection point corresponds to a phase tuning range;

a second demultiplexer to inject the input signal into one or more injection points of a second ILO based on the second select signal, wherein each injection point corresponds to a phase tuning range; and

a phase detector to generate a phase detector output signal that is indicative of a phase difference between the first and the second output signals.

11. The controller device of claim 10, wherein the circuitry to detect the phase boundary further comprises:

selection circuitry to generate the second select signal so that the second demultiplexer injects the input signal into multiple injection points of the second ILO; and

sweeping circuitry to generate the first control signal to sweep the first free-running frequency of the first ILO until the phase detector output signal indicates that the phase difference between the first and the second output signals is substantially equal to a pre-determined value.

12. The controller device of claim 10,

wherein the selection circuitry is capable of generating the first select signal so that the first demultiplexer injects the input signal into multiple injection points of the first ILO;

and

wherein the sweeping circuitry is capable of generating the second control signal to sweep the second free-running frequency of the second ILO until the phase detector output signal indicates that the phase difference between the first and the second output signals is substantially equal to a pre-determined value.

13. The controller device of claim 10, wherein the circuitry to detect the phase boundary further comprises:

selection circuitry to generate the first and the second select signals so that the first demultiplexer injects the input signal into a first injection point of the first ILO and the second demultiplexer injects the input signal into a second injection point of the second ILO, wherein the first and the second injection points correspond to adjacent phase tuning ranges; and

sweeping circuitry to generate the first and the second control signals to concurrently sweep, in opposite directions, the first and the second free-running frequencies until the phase detector output signal indicates that the phase difference between the first and the second output signals is substantially equal to a pre-determined value.

14. The controller device of claim 9, wherein the circuitry to detect the phase boundary generates a third select signal, the circuit further comprising a multiplexer to select, based on the third select signal, one of the first and second output signal as an output signal of the circuit, and wherein the circuitry to detect the phase boundary comprises a phase controller to generate, based on the phase boundary between the two adjacent phase tuning ranges, the first and the second control signals, the first and the second select signals, and the output select signal.

15. The controller device of claim 9, wherein the circuitry to detect the phase boundary generates a third select signal, the circuit further comprising a multiplexer to select, based on the third select signal, one of the first and the second output signal as an output signal of the circuit, wherein the circuitry to detect the phase boundary comprises:

a phase detector to generate a phase detector output signal that is indicative of a phase difference between the first and the second output signals; and

a phase controller to generate, based on received phase information and the phase detector output signal, the first and the second control signals, the first and the second select signals, and the output select signal.

16. The controller device of claim 15, wherein the phase controller is capable of switching between adjacent phase tuning ranges in response to the phase detector output signal indicating that the phase difference between the first and the second output signals is substantially equal to a pre-determined value.

17. A method for determining a phase boundary between two adjacent phase tuning ranges, comprising:

a first injection-locked oscillator (ILO) generating a first output signal based on an input signal, wherein the first ILO has a first free-running frequency that is capable of being adjusted based on a first control signal, wherein the first ILO has multiple phase tuning ranges capable of being selected based on a first select signal;

a second ILO generating a second output signal based on the input signal, wherein the second ILO has a second free-running frequency that is capable of being adjusted based on a second control signal, wherein the second ILO has multiple phase tuning ranges capable of being selected based on a second select signal; and

in response to determining that a phase difference between the first and the second output signals is not substantially equal to a pre-determined value, adjusting the first control signal, the second control signal, or both the first and the second control signals in opposite directions.

18. The method of claim 17, further comprising, in response to determining that the phase difference between the first and the second output signals is substantially equal to a pre-determined value, storing the first control signal, the second control signal, or both the first and the second control signals.

19. A circuit, comprising:

a phase controller to generate, based on received phase information, a first and a second control signal, a first and a second injection select signal, and an output select signal;

a first demultiplexer to inject a first injection signal into one of multiple injection points of a first injection-locked oscillator (ILO) based on the first injection select signal;

the first ILO to output a first output signal, wherein the first ILO has a first free-running frequency that is capable of being adjusted based on the first control signal;

a second demultiplexer to inject a second injection signal into one of multiple injection points of a second ILO based on the second injection select signal;

the second ILO to output a second output signal, wherein the second ILO has a second free-running frequency that is capable of being adjusted based on the second control signal; and

a multiplexer to select the first or the second output signal based on the output select signal.

20. The circuit of claim 19, wherein each of the first ILO and the second ILO is based on a ring oscillator.

21. The circuit of claim 19, wherein each of the first ILO and the second ILO is based on a tank circuit.