Method and apparatus for generating a phase dependent control signal

• US 20050286505A1
• Filed: 08/12/2005
• Published: 12/29/2005
• Est. Priority Date: 03/01/1999
• Status: Active Grant

• Current Assignee: Round Rock Research LLC
• Original Assignee: Ronnie M. Harrison
• Inventors: Harrison, Ronnie M.
• Granted Patent: US 7,418,071 B2
• Time in Patent Office: Days
• US Class Current: 370/359
• CPC Class Codes: G11C 7/1072 for memories with random access ports synchronised on clock signal pulse trains, e.g. synchronous memories, self timed memories
• CPC Class Codes: G11C 7/222 Clock generating, synchronizing or distributing circuits within memory device
• 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: H03K 5/131 Digitally controlled
• CPC Class Codes: H03K 5/133 using a chain of active delay devices
• CPC Class Codes: H03K 5/135 by the use of time reference signals, e.g. clock signals
• CPC Class Codes: H03L 7/07 using several loops, e.g. for redundant clock signal generation
• CPC Class Codes: H03L 7/0816 the controlled phase shifter and the frequency- or phase-detection arrangement being connected to a common input
• 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 7/0896 the current generators being controlled by differential up-down pulses

Abstract

A phase detector generates a phase dependent control signal according to the phase relationship between a first and second clock signal. The phase detector includes first and second phase detector circuits receiving the first and second clock signals and generating select signals having duty cycles corresponding to the phase relationship between the clock edges of the first and second clock signals. The phase detector also includes a charge pump that receives select signals from the phase detector circuits and produces an increasing or decreasing control signal when the first and second clock signals do not have the predetermined phase relationship, and a non-varying control signal when the first and second clock signals do have the predetermined phase relationship. The control signal may be used to adjust the delay value of a voltage-controlled delay circuit in order to adjust the phase relationship between the first and second clock signals to have a predetermined phase relationship.

Claims

1. A phase detector for providing a control signal according to the phase relationship between a first and second clock signal, the phase detector comprising:

a first phase detector circuit having first and second input terminals coupled to receive the first and second clock signals, respectively, and an output terminal, the first phase detector circuit producing a first select signal having a duty cycle according to the phase relationship between a first clock edge of the respective clock signals;

a second phase detector circuit having first and second input terminals coupled to receive the first and second clock signals, respectively, and an output terminal, the second phase detector circuit producing a second select signal having a duty cycle according to the phase relationship between a second clock edge of the respective clock signals; and

a charge pump having first and second input terminals coupled to the output terminals of the first and second phase detector, the charge pump producing a non-varying control signal responsive to a first combination of logic levels of the first and second select signals, an increasing control signal responsive to a third combination of logic levels of the first and second select signals, and a decreasing control signal responsive to a third combination of logic levels of the first and second select signals.

2-33. -33. (canceled)