Phase-locked loop circuit, recording-and-reproducing apparatus, and electronic appratus

• US 20100026406A1
• Filed: 07/21/2009
• Published: 02/04/2010
• Est. Priority Date: 07/31/2008
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Fujiwara, Tetsuya, Ueno, Yosuke
• Granted Patent: US 8,089,317 B2
• Time in Patent Office: Days
• US Class Current: 331/36.R
• CPC Class Codes: H03L 2207/06 Phase locked loops with a controlled oscillator having at least two frequency control terminals
• 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 7/0893 the up-down pulses controlling at least two source current generators or at least two sink current generators connected to different points in the loop
• CPC Class Codes: H03L 7/0898 the source or sink current values being variable H03L7/0896 takes precedence
• CPC Class Codes: H03L 7/093 using special filtering or amplification characteristics in the loop H03L7/087 - H03L7/091 take 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 7/1976 using a phase accumulator for controlling the counter or frequency divider

Abstract

A phase-locked loop circuit includes a phase detection unit, a loop filter unit including a series circuit of a resistor and a capacitor, first and second pulse-current output units which supply differential and single-end pulse currents corresponding to phase information to the resistor and capacitor, an oscillating unit which varies an oscillation frequency in accordance with a voltage generated at the resistor and capacitor, and a calibration unit which obtains information of an oscillation gain in actual operation and corrects an operation of the oscillating unit on the basis of a difference between the oscillation gain in actual operation and a target oscillation gain. The oscillation gain in actual operation represents a characteristic of oscillation frequency versus input signal of the oscillating unit and is obtained using predetermined oscillation control signals on the basis of a difference between actual oscillation frequencies under the oscillation control signals.

Claims

1. A phase-locked loop circuit, comprising:

a phase detection unit which detects phase information of an input signal;

a loop filter unit which includes a series circuit of a resistor circuit and a capacitor circuit, a terminal of the capacitor circuit opposite the resistor circuit being connected to a reference point;

a first pulse-current output unit which supplies a differential pulse current to one of the resistor circuit and the capacitor circuit from a positive-phase output terminal and a negative-phase output terminal, the differential pulse current corresponding to the phase information output from the phase detection unit;

a second pulse-current output unit which supplies a single-end pulse current to the other one of the resistor circuit and the capacitor circuit from a single output terminal, the single-end pulse current corresponding to the phase information output from the phase detection unit;

an oscillating unit capable of varying an oscillation frequency in accordance with a component obtained by combining a voltage generated at both ends of the one of the resistor circuit and the capacitor circuit on the basis of the differential pulse current supplied from the positive-phase output terminal and the negative-phase output terminal of the first pulse-current output unit and a voltage generated at both ends of the other one of the resistor circuit and the capacitor circuit on the basis of the single-end pulse current supplied from the single output terminal of the second pulse-current output unit; and

a calibration unit which obtains information of an oscillation gain in actual operation and corrects an oscillating operation of the oscillating unit on the basis of a difference between the oscillation gain in actual operation and a target oscillation gain, the oscillation gain in actual operation representing a characteristic of oscillation frequency versus input signal of the oscillating unit and being obtained using oscillation control signals for correction with predetermined magnitudes on the basis of a difference between actual oscillation frequencies under the oscillation control signals.

2. The phase-locked loop circuit according to claim 1, wherein the calibration unit includes

a reference potential generator which generates a reference voltage with a predetermined magnitude;

a current bias unit which includes a reference resistor having a resistance with a reference magnitude, which generates a reference current with a predetermined magnitude on the basis of the reference voltage generated by the reference potential generator and the reference resistor, and which generates a bias current for correction of the oscillation gain by mirroring the reference current; and

a correction control signal generator which generates the oscillation control signals for correction on the basis of the bias current for correction generated by the current bias unit.

3. The phase-locked loop circuit according to claim 2,

wherein the correction control signal generator includes a series circuit of a resistor element through which the bias current for correction flows and a transistor having a temperature characteristic that matches a temperature characteristic of a transistor included in the oscillating unit, and

wherein the reference resistor and the resistor element through which the bias current for correction flows have substantially the same temperature variation characteristic.

4. The phase-locked loop circuit according to one of claims 1 to 3,

wherein the calibration unit includes

a reference potential generator which generates a reference voltage with a predetermined magnitude, and

a current bias unit which includes a reference resistor having a resistance with a reference magnitude, which generates a reference current with a predetermined magnitude on the basis of the reference voltage generated by the reference potential generator and the reference resistor, and which generates a bias current for driving the resistor circuit by mirroring the reference current,

wherein the reference resistor and the resistor circuit have substantially the same temperature variation characteristic, and

wherein one of the first pulse-current output unit and the second pulse-current output unit which drives the resistor circuit generates a pulse current with a magnitude corresponding to the bias current for driving the resistor circuit generated by the current bias unit.

5. A read/write apparatus, comprising:

at least one of a clock recovery unit and a write-clock generating unit, the clock recovery unit generating a reproduction clock on the basis of phase information of a reproduction signal read from a recording medium, the write-clock generating unit generating a write clock for modulating data in a process of writing information on the recording medium on the basis of a reference clock,

wherein the at least one of the clock recovery unit and the write-clock generating unit includes a phase-locked loop circuit, and

wherein the phase-locked loop circuit includes

a phase detection unit which detects phase information of an input signal,

a loop filter unit which includes a series circuit of a resistor circuit and a capacitor circuit, a terminal of the capacitor circuit opposite the resistor circuit being connected to a reference point,

a first pulse-current output unit which supplies a differential pulse current to one of the resistor circuit and the capacitor circuit from a positive-phase output terminal and a negative-phase output terminal, the differential pulse current corresponding to the phase information output from the phase detection unit,

a second pulse-current output unit which supplies a single-end pulse current to the other one of the resistor circuit and the capacitor circuit from a single output terminal, the single-end pulse current corresponding to the phase information output from the phase detection unit,

an oscillating unit capable of varying an oscillation frequency in accordance with a component obtained by combining a voltage generated at both ends of the one of the resistor circuit and the capacitor circuit on the basis of the differential pulse current supplied from the positive-phase output terminal and the negative-phase output terminal of the first pulse-current output unit and a voltage generated at both ends of the other one of the resistor circuit and the capacitor circuit on the basis of the single-end pulse current supplied from the single output terminal of the second pulse-current output unit, and

a calibration unit which obtains information of an oscillation gain in actual operation and corrects an oscillating operation of the oscillating unit on the basis of a difference between the oscillation gain in actual operation and a target oscillation gain, the oscillation gain in actual operation representing a characteristic of oscillation frequency versus input signal of the oscillating unit and being obtained using oscillation control signals for correction with predetermined magnitudes on the basis of a difference between actual oscillation frequencies under the oscillation control signals.

6. An electronic apparatus, comprising:

a phase-locked loop circuit; and

a signal processor which performs a signal processing operation on the basis of a signal output form the phase-locked loop circuit,

wherein the phase-locked loop circuit includes

a phase detection unit which detects phase information of an input signal,

a loop filter unit which includes a series circuit of a resistor circuit and a capacitor circuit, a terminal of the capacitor circuit opposite the resistor circuit being connected to a reference point,

a first pulse-current output unit which supplies a differential pulse current to one of the resistor circuit and the capacitor circuit from a positive-phase output terminal and a negative-phase output terminal, the differential pulse current corresponding to the phase information output from the phase detection unit,

a second pulse-current output unit which supplies a single-end pulse current to the other one of the resistor circuit and the capacitor circuit from a single output terminal, the single-end pulse current corresponding to the phase information output from the phase detection unit,

an oscillating unit capable of varying an oscillation frequency in accordance with a component obtained by combining a voltage generated at both ends of the one of the resistor circuit and the capacitor circuit on the basis of the differential pulse current supplied from the positive-phase output terminal and the negative-phase output terminal of the first pulse-current output unit and a voltage generated at both ends of the other one of the resistor circuit and the capacitor circuit on the basis of the single-end pulse current supplied from the single output terminal of the second pulse-current output unit, and

a calibration unit which obtains information of an oscillation gain in actual operation and corrects an oscillating operation of the oscillating unit on the basis of a difference between the oscillation gain in actual operation and a target oscillation gain, the oscillation gain in actual operation representing a characteristic of oscillation frequency versus input signal of the oscillating unit and being obtained using oscillation control signals for correction with predetermined magnitudes on the basis of a difference between actual oscillation frequencies under the oscillation control signals.