Phase difference detector having concurrent fine and coarse capabilities

• US 7,734,002 B2
• Filed: 11/14/2006
• Issued: 06/08/2010
• Est. Priority Date: 11/14/2006
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Inventors: Yi, Li
• Primary Examiner(s): Torres; Juan A
• Application Number:
  US11/599,895
• Publication Number:
  US 20080112526A1
• Time in Patent Office: 1,302 Days
• Field of Search: 375/376, 327/156, 331/25
• US Class Current: 375/376
• CPC Class Codes: H03D 13/004 the logic means delivering pulses at more than one terminal, e.g. up and down pulses
• CPC Class Codes: H03L 2207/50 All digital phase-locked loop
• CPC Class Codes: H03L 7/07 using several loops, e.g. for redundant clock signal generation
• CPC Class Codes: H03L 7/085 concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal H03L7/10 takes precedence; circuits for comparing the phase or frequency of two mutually-independent oscillations H03D13/00
• CPC Class Codes: H03L 7/087 using at least two phase detectors or a frequency and phase detector in the loop
• CPC Class Codes: H03L 7/1077 by changing characteristics of the phase or frequency detection means H03L7/1072 takes precedence

Abstract

A phase difference detector having concurrent fine and coarse capabilities synchronizes operations of coarse and fine phase detectors. In one embodiment, clusters of fine timing markers are generated by delay stages of a delay locked loop. The K'"'"'th one of every cluster of J fine timing markers is designated as a coarse marker. A first timer determines which of J fine markers in a first cluster is closest to a rising edge of a reference signal. A second timer determines which of J fine markers in a second cluster is closest to a rising edge of a follower signal. A third timer determines how many coarse markers separate the rising edges of the reference and follower signals. Temporal displacement values obtained from the determinations of the first though third timers are combined to produce a phase displacement measurement signal of broad range and high precision across its operating range.

Claims

1. A chronometer for measuring respective chronological displacements between first edges of a first switched signal and corresponding second edges of a second switched signal, the chronometer comprising:

(a) a timing marks receiver that receives a common set of chronologically spaced-apart timing markers including a set of spaced-apart coarse timing markers and including, for each coarse timing marker, a cluster of plural spaced-apart fine timing markers, where each cluster can align temporally in accordance with a predefined orientation relative to its respective coarse marker, and where at least some of the fine timing markers are temporally interposed between the coarse timing markers;

(b) a coarse locations determiner, operatively coupled to the timing marks receiver, for designating a first of the coarse timing markers as corresponding to a given first edge of the first switched signal, for designating a second of the coarse timing markers as corresponding to a given second edge of the second switched signal; and

for generating therefrom a coarse displacement signal that coarsely represents a chronological displacement present between the given first and second edges of the respective first and second switched signals;

(c) a first fine location determiner, operatively coupled to the timing marks receiver, for identifying a first of the fine timing markers in the cluster of the designated first coarse timing marker as a fine marker that temporally lies at or immediately adjacent to the given first edge; and

(d) a second fine location determiner, operatively coupled to the timing marks receiver, for identifying a second of the fine timing markers in the cluster of the designated second coarse timing marker as one that temporally lies at or immediately adjacent to the given second edge.

2. The chronometer of claim 1 and further comprising:

(e) one or more fine correction generators, operatively coupled to at least one of the first and second fine location determiners, for generating a corresponding one or more fine timing correction signals representing fine corrections to be added to the coarse temporal displacement signal for thereby producing a finely corrected displacement signal that represents the chronological displacement between the given first and second edges with better accuracy than that of the coarse temporal displacement signal.

3. The chronometer of claim 2 wherein:

said first switched signal is a supplied reference signal; and

said second switched signal is a follower signal generated by a variable pulse generator whose operations are responsive to the finely corrected displacement signal.

4. The chronometer of claim 2 wherein:

(cd.1) said first and second fine location determiners operate in parallel so as to thereby identify their respective ones of the first and second fine timing markers in substantially concurrent or other time-wise parallel fashion.

5. The chronometer of claim 4 wherein:

(e.1) said one or more fine correction generators operate in parallel in the case where there are at least two fine correction generators, so as to thereby produce their respective fine timing correction signals in substantially concurrent or other time-wise parallel fashion.

6. The chronometer of claim 2 wherein:

said first and second fine location determiners output pattern signals indicative of respective identifications of which of said fine timing markers in the respective clusters temporally lie at or immediately adjacent to corresponding ones of the given first and second edges; and

(e.1) said one or more fine correction generators each includes a pattern decoder for recognizing distinctions among the output pattern signals and said one or more fine correction generators each includes a respective mapping table for producing a respective one of said fine timing correction signals as a pre-mapped response to the recognized distinctions of its corresponding pattern decoder.

7. The chronometer of claim 1 wherein:

(b.1) the coarse locations determiner includes a saturating slip counter.

8. The chronometer of claim 1 wherein:

(c.1) the first fine location determiner includes a slate erasing mechanism for repeatedly wiping clean a plurality of flippable registers and a flip-blocking mechanism for blocking predefined subsets of the flippable registers from flipping after a first of the flippable registers flips immediately following a slate erasing operation.

9. The chronometer of claim 1 wherein:

(c.1) the first fine location determiner includes a detection pass terminating mechanism and a snapshot taking mechanism.

10. The chronometer of claim 1 and further comprising:

(e) a course timing marks generator for generating and supplying the spaced-apart coarse timing markers to the timing marks receiver, the coarse timing marks generator including coarse marker spacing means for causing the coarse timing markers to be equally spaced-apart from one another by a pre-defined coarse chronological spacing.

11. The chronometer of claim 1 and further comprising:

(e) a fine timing marks generator for generating and supplying the spaced-apart fine timing markers to the timing marks receiver, the fine timing marks generator including fine marker spacing means for causing the fine timing markers of each cluster to be equally spaced-apart from one another by a pre-defined fine chronological spacing.

12. The chronometer of claim 1 and further comprising:

(e) a fine-to-coarse aligning means for causing said clusters of fine markers to align temporally in accordance with one or more predefined orientations relative to their respective coarse markers.

13. The chronometer of claim 12 wherein:

(e.1) the fine-to-coarse aligning means causes each cluster of fine markers to align temporally in an essentially identical manner to its respective coarse marker.

14. The chronometer of claim 1 and further comprising:

(e) a consistent timing marks generator for generating and supplying the spaced-apart fine timing markers to the timing marks receiver, the fine timing marks generator including a substantially invariant oscillator for causing temporal spacings between the fine timing markers of each cluster to be consistent over a predefined operating temperature range.

15. The chronometer of claim 1 wherein:

(c.1) the first fine location determiner includes a sampling history logger for sampling the first switched signal at sampling time points defined by the fine timing markers in the cluster of a corresponding first coarse timing marker and for registering the sampling results.

16. The chronometer of claim 15 wherein:

(c.2) the first fine location determiner includes a samples stabilizer coupled to the sampling history logger for allowing the registered samples to settle into stabilized states.

17. The chronometer of claim 16 wherein:

(c.3) signal propagation delay through the sampling history logger and through the samples stabilizer is essentially identical for each of the samples taken of the first switched signal at said sampling time points.

18. The chronometer of claim 1 wherein:

said coarse locations determiner, first fine location determiner, and second fine location determiner operate concurrently.

19. A method of measuring respective chronological displacements between first edges of a first switched signal and corresponding second edges of a second switched signal, the method comprising:

(a) receiving a set of chronologically spaced-apart timing signals including a set of spaced-apart coarse timing markers and for each coarse timing marker, a cluster of spaced-apart fine timing markers, where each cluster can align temporally in accordance with a predefined orientation relative to its respective coarse marker, and where upon alignment at least some of the fine timing markers are temporally interposed between the coarse timing markers;

(b) first designating a first of the coarse timing markers as corresponding to a given first edge of the first switched signal;

(c) second designating a second of the coarse timing markers as corresponding to a given second edge of the second switched signal;

(d) in response to said first and second designating steps, (b) and (c), generating a coarse displacement signal that coarsely represents a chronological displacement present between the given first and second edges of the respective first and second switched signals;

(e) first identifying a first of the fine timing markers in the cluster of the designated first coarse timing marker as a fine marker that temporally lies at or immediately adjacent to the given first edge; and

(f) second identifying a second of the fine timing markers in the cluster of the designated second coarse timing marker as one that temporally lies at or immediately adjacent to the given second edge.

20. The measuring method of claim 19 and further comprising:

(g) in response to one or more of the first and second identifying steps (e) and (f), generating a corresponding one or more fine timing correction signals representing fine corrections to be added to the coarse temporal displacement signal for thereby producing a finely corrected displacement signal that represents the chronological displacement between the given first and second edges with better accuracy than that of the coarse temporal displacement signal.

21. The measuring method of claim 20 wherein:

said first switched signal is a supplied reference signal; and

said second switched signal is a follower signal generated by a variable pulse generator;

the method further comprising;

(h) varying operations of the variable pulse generator in response to the finely corrected displacement signal.

22. The measuring method of claim 20 wherein:

(ef.1) said first and second fine identifying steps occur in parallel-operating fine position determining circuits so as to thereby identify their respective ones of the first and second fine timing markers.

23. The measuring method of claim 20 wherein:

(g.1) in the case where at least two fine correction signals are generated, said generating of the one or more fine correction signals occurs by way of parallel generating paths.

24. The measuring method of claim 20 wherein:

said first and second identifying steps output pattern signals indicative of respective identifications of which of said fine timing markers in the respective clusters temporally lie at or immediately adjacent to corresponding ones of the given first and second edges; and

(g.1) said step (g) of generating a corresponding one or more fine timing correction signals includes decoding the output pattern signals so as to thereby recognize distinctions among the output pattern signals and mapping the decodings of the output pattern signals to respective and predefined fine timing correction signal magnitudes.

25. The measuring method of claim 19 wherein:

(d.1) said generating a coarse displacement signal includes using a saturating slip counter to coarsely count off a number of coarse markers present between the given first and second edges of the respective first and second switched signals.

26. The measuring method of claim 19 wherein:

(e.1) said first identifying of a first of the fine timing markers includes repeatedly wiping clean a plurality of flippable registers and employing a flip-blocking mechanism for blocking predefined subsets of the flippable registers from flipping after a first of the flippable registers flips immediately following a slate cleaning operation.

27. The measuring method of claim 19 wherein:

(e.1) said first identifying of a first of the fine timing markers includes terminating a detection run that detects first transitions along a time scale of the fine timing markers and taking a snapshot of the terminated detection run.

28. The measuring method of claim 19 and further comprising:

(g) generating the spaced-apart coarse timing markers so as to be equally spaced-apart from one another by a pre-defined coarse chronological spacing.

29. The measuring method of claim 19 and further comprising:

(g) generating the fine timing markers of each cluster so as to be equally spaced-apart from one another by a pre-defined fine chronological spacing.

30. The measuring method of claim 19 and further comprising:

(g) causing the clusters of fine markers to align temporally in accordance with one or more predefined orientations relative to their respective coarse markers.

31. The measuring method of claim 30 wherein:

(g.1) said causing of temporal alignment includes causing each of the clusters of fine markers to align temporally in an essentially identical manner to its respective coarse marker.

32. The measuring method of claim 19 wherein:

(e.1) said step of (e) first identifying includes sampling the first switched signal at sampling time points defined by the fine timing markers in the cluster of a corresponding first coarse timing marker and registering the sampling results.

33. The measuring method of claim 32 wherein:

(e.2) said step of (e) first identifying includes delaying the registered sampling results by at least one coarse sampling interval so as to thereby allow the registered samples to settle into stable discrete states.

34. The measuring method of claim 33 wherein:

(e.3) said delaying of the registered sampling results is essentially identical for each of the samples taken of the first switched signal at said sampling time points.

35. The measuring method of claim 19 wherein:

said steps of generating the coarse displacement signal and of identifying the first of the fine timing markers and of identifying the second of the fine timing markers occur by operation of parallel signal generating circuits.

36. A phase difference detector comprising:

(a) a first fine edge locater for determining a first phase relation between a supplied first switching signal and a supplied plurality of finely out-of phase clock signals;

(b) a second fine edge locater for determining a second phase relation between a supplied second switching signal and the supplied plurality of finely out-of phase clock signals; and

(c) a fine displacement determiner, responsive to the first and second fine edge locaters and receiving coarse marker signals which can be used to designate coarse timings of respective switching edges of the first and second switching signals, the fine displacement determiner providing one or more indications of fine phase differences between the switching edges of the first and second switching signals and respective ones of the coarse marker signals.

37. The phase difference detector of claim 36 and further comprising:

(d) a coarse difference determiner, operating in parallel with and in synchronism with the fine edge locaters as well as in synchronism with the coarse marker signals and providing an indication of a coarse phase difference between corresponding switching edges of the first and second switching signals.

38. The phase difference detector of claim 37 wherein:

said indication of the coarse phase difference temporally aligns with the said one or more indications of the fine phase differences so the coarse and fine indications can be arithmetically combined to thereby provide a more accurate, total phase difference indication for representing phase displacement between corresponding switching edges of the first and second switching signals.

39. The phase difference detector of claim 36 and further comprising:

(d) a fine phases generator for generating a plurality of finely out-of phase clock signals for thereby supplying said plurality of finely out-of phase clock signals.

40. The phase difference detector of claim 39 wherein:

(d.1) said fine phases generator includes a delay locked loop (DLL).

41. The phase difference detector of claim 40 wherein:

(d.2) said DLL locks into phase with a frequency regulated clock signal.

42. The phase difference detector of claim 39 wherein:

(d.1) said fine phases generator includes a frequency divider.