PLL circuit having a multi-band oscillator and compensating oscillation frequency

• US 7,263,340 B2
• Filed: 07/25/2006
• Issued: 08/28/2007
• Est. Priority Date: 05/31/2002
• Status: Expired due to Fees

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Renesas Technology Corporation (Renesas Electronics Corporation), Ttpcom Limited
• Inventors: Uozumi, Toshiya, Kasahara, Masumi, Tanaka, Satoshi, Kimura, Yasuyuki, Henshaw, Robert Astle, Oosawa, Hirotaka
• Primary Examiner(s): Urban; Edward F.
• Assistant Examiner(s): CHOW, CHARLES CHIANG
• Application Number:
  US11/491,978
• Publication Number:
  US 20060258313A1
• Time in Patent Office: 399 Days
• Field of Search: 455/252.1, 455/255, 455/258, 455/260, 455/262, 455/264, 455/333, 455/334, 455/425, 455/550.1, 455/575.1, 455/561, 455/412.1, 455/418, 455/67.11, 455/456.5, 455/456.6, 455/67.14, 455/147, 455/180.3, 455/183.1, 455/186.1, 455/185.1, 455/226.1, 455316-318, 455/424, 455/63.1, 455/208, 455/182.1, 455/161.1, 331/17, 331/25, 331/44, 331/1.R, 331/176, 331/107.R, 331/66, 331/68, 331/177.R, 331/16, 331/175, 327/138, 327/156, 327/157, 327/127
• US Class Current: 455/255
• CPC Class Codes: H03L 1/02 against variations of temperature only
• 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 7/099 concerning mainly the controlled oscillator of the loop
• CPC Class Codes: H03L 7/183 a time difference being used for locking the loop, the counter counting between fixed numbers or the frequency divider dividing by a fixed number H03L7/1806 takes precedence
• CPC Class Codes: H03L 7/187 using means for coarse tuning the voltage controlled oscillator of the loop H03L7/191 - H03L7/195 take precedence

Abstract

A semiconductor integrated circuit device for communication is provided with a PLL circuit or the like formed therein, the PLL circuit which is capable of realizing the compensation of fluctuation due to temperature change, the inhibition of increase in the chip area and the ensurement of the performance margin, and which controls a VCO having multiple oscillation frequency bands. In the case where automatic calibration is performed by switching a switch to a side of a DC voltage source in the PLL circuit using a VCO having multiple oscillation bands, a tuning voltage (Vtune) of an RFVCO is fixed to a voltage value of a DC voltage source. However, since a temperature characteristic of canceling a VCO oscillation frequency is given to the DC voltage source, it is possible to minimize the influence on the band selection when a calibration table comes to no optimum one.

Claims

1. A method of correcting a voltage controlled oscillator for oscillating in a plurality of frequency bands, comprising:

a setting step for setting said voltage controlled oscillator to a first frequency band;

a measuring step for measuring an oscillation frequency of said voltage controlled oscillator according to a predetermined control voltage;

a comparing step for comparing the measured value with a target reference frequency to determine whether or not the measured value matches the target reference frequency;

a re-measuring step for measuring a new measured value for selecting said first frequency band for oscillation of said voltage controlled oscillator when the measured value matches the target reference frequency, setting said voltage controlled oscillator to a new frequency band and measuring the oscillator output frequency at said predetermined control voltage to obtain a new measured value when the measured value does not match the target reference frequency; and

a repeating step for repeating said comparing step using the new measured value and said target reference frequency and acting on the result to either select said new frequency band for oscillation of said voltage controlled oscillator or setting said voltage controlled oscillator to another new frequency band and repeating the measure and comparing steps if necessary until a frequency band has been selected.

2. The method according to claim 1, in which the oscillator includes a phase locked loop with a switch in the input path to said voltage controlled oscillator which is operated to provide said predetermined control voltage,

wherein said phase locked loop further comprises a phase detector and loop filter in the input path, and the switch serves to disconnect the loop filter from the phase detector and connect it to a voltage source.

3. The method according to claim 1, in which the oscillator includes a phase locked loop with a switch in the input path to said voltage controlled oscillator which is operated to provide said predetermined control voltage,

wherein said phase locked loop comprises a phase detector and loop filter in the input path, and the switch serves to disconnect the loop filter from the phase detector and connect it to a current source that causes the loop filter to generate said predetermined control voltage.

4. The method according to claim 1, in which a counter is provided to count cycles of voltage controlled oscillator output frequency over a fixed period of time to determine said calibration values of the output frequency.