Dual loop phase lock loops using dual voltage supply regulators

Details Dual loop phase lock loops using dual voltage supply regulators Dual loop phase lock loops using dual voltage supply regulators

2001-09-17

2003-01-07

Callahan, Timothy P. (Department: 2816)

Oscillators

Automatic frequency stabilization using a phase or frequency...

Particular error voltage control

C331S010000, C331S00100A

Reexamination Certificate

active

06504438

ABSTRACT:

TECHNICAL FIELD
This invention relates to phase lock loops and, in particular, to dual-loop phase lock loops.
BACKGROUND
Clock recovery circuits are required in many of today's high speed integrated circuit devices to generate a clock signal having a certain timing relationship with a reference signal. Clock recovery circuits can be employed to generate clock signals having a synchronous, controlled and/or predetermined relationship with a reference signal such as an external clock signal. By integrating clock recovery circuitry into a clock system of, for example, a microprocessor or synchronous memory device, difficulties relating to maintaining or ensuring signal integrity and clock skew can be overcome. In addition, reliable clocking operations which support very high speed circuit implementations can be achieved.
One type of a clock recovery circuit is a phase lock loop (PLL). A phase lock loop circuit, for example, utilizes a voltage controlled oscillator (VCO) to generate a recovered clock signal having a certain timing relationship with a reference signal. A dual loop phase lock loop can incorporate so-called phase mixers (more appropriately termed “phase adjusters”) in a second loop of the PLL. The phase mixers are associated with voltage controlled oscillator and can provide a feedback loop to a suitable phase frequency detector which detects differences in the phase frequency between the output of the phase mixers (an internal clock) and a reference clock (an external clock).
One problem associated with dual loop phase lock loops is that of trying to maintain high loop bandwidth for the inner analog PLL loop while maintaining low power consumption. Accordingly, this invention arose out of concerns associated with providing improved dual loop phase lock loops having a suitably high inner loop bandwidth while maintaining low power consumption.


REFERENCES:
patent: 4987387 (1991-01-01), Kennedy et al.
patent: 5315623 (1994-05-01), Kuo
patent: 5334953 (1994-08-01), Mijuskovic
patent: 5642082 (1997-06-01), Jefferson
patent: 5854575 (1998-12-01), Fiedler et al.
patent: 5912574 (1999-06-01), Bhagwan
patent: 6054903 (2000-04-01), Fiedler
Wei et al.,“A Variable-Frequency Parallel I/O Interface with Adaptive Power-Supply Regulation”, Nov. 2000, 11 pages.

Affiliated with

Also associated with

Rating

Dual loop phase lock loops using dual voltage supply regulators does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Dual loop phase lock loops using dual voltage supply regulators, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dual loop phase lock loops using dual voltage supply regulators will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3000737