Phase-locked loop with variable parameters

Details Phase-locked loop with variable parameters Phase-locked loop with variable parameters

1997-09-26

2000-05-02

Grimm, Siegfried H.

Oscillators

Automatic frequency stabilization using a phase or frequency...

With intermittent comparison controls

331 17, 331 25, H03L 7089, H03L 7093

Patent

active

060577398

ABSTRACT:
An electronic system such as a processor or computer system includes a phase-locked loop (PLL) having a PLL parameter modification circuit. In one embodiment, the PLL parameter modification circuit may be programmed to provide one of several current control signals to a charge pump. Additionally, the PLL parameter modification circuit may be programmed to alter a loop filter transfer function by selectively changing resistance and/or capacitance values of the loop filter. Each current control signal modifies the charge pump output control voltage to a VCO differently, and, thus, modifying the current control signals to the charge pump effectively modifies the bandwidth of the PLL. In one embodiment, the PLL parameter modification circuit modifies current control signals to the charge pump by selectively inserting and removing, in accordance with programmable register bit(s) states, diode configured transistors in a current mirror configuration. Thus, a ratio of the output current of the current mirror i.e. the current control signals, to a current reference signal may be programmably modified to modify the bandwidth and lock time parameters of the PLL. The PLL parameter modification may modify the resistive and capacitive parameters of the loop filter by selecting configuring multiple resistors and capacitors to form one of many equivalent circuits.

REFERENCES:
patent: 5151665 (1992-09-01), Wentzler
patent: 5276408 (1994-01-01), Norimatsu
patent: 5339050 (1994-08-01), Llewellyn
patent: 5404250 (1995-04-01), Hase et al.
patent: 5631587 (1997-05-01), Co et al.
patent: 5831483 (1998-11-01), Fukuda
Digital Integrated Circuits, A Design Perspective; Jan M. Rabaey; Prentice Hall Electronics and VLSI Series; .COPYRGT.1996 by Prentice-Hall, Inc.; Upper Saddle River, New Jersey 07458; pp. 538-545.

Affiliated with

Also associated with

Rating

Phase-locked loop with variable parameters does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Phase-locked loop with variable parameters, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Phase-locked loop with variable parameters will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1596847