JP2007019565A - Crystal oscillator - Google Patents

Crystal oscillator Download PDF

Info

Publication number
JP2007019565A
JP2007019565A JP2003380479A JP2003380479A JP2007019565A JP 2007019565 A JP2007019565 A JP 2007019565A JP 2003380479 A JP2003380479 A JP 2003380479A JP 2003380479 A JP2003380479 A JP 2003380479A JP 2007019565 A JP2007019565 A JP 2007019565A
Authority
JP
Japan
Prior art keywords
voltage
variable capacitance
mos type
capacitance element
voltage variable
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2003380479A
Other languages
Japanese (ja)
Inventor
Souyo Yamamoto
壮洋 山本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Miyazaki Epson Corp
Original Assignee
Miyazaki Epson Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Miyazaki Epson Corp filed Critical Miyazaki Epson Corp
Priority to JP2003380479A priority Critical patent/JP2007019565A/en
Priority to PCT/JP2004/014964 priority patent/WO2005046046A1/en
Publication of JP2007019565A publication Critical patent/JP2007019565A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/02—Details
    • H03B5/04—Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/30—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator
    • H03B5/32—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator being a piezoelectric resonator
    • H03B5/36—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator being a piezoelectric resonator active element in amplifier being semiconductor device
    • H03B5/366—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element being electromechanical resonator being a piezoelectric resonator active element in amplifier being semiconductor device and comprising means for varying the frequency by a variable voltage or current

Landscapes

  • Oscillators With Electromechanical Resonators (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystal oscillator that exhibits an increased oscillator frequency variation amount in accordance with an externally supplied control voltage and that provides a frequency variation exhibiting an improved linearity. <P>SOLUTION: The crystal oscillator is characterized in to include a frequency adjusting circuit configured by use of MOS voltage variable capacitance elements, the frequency adjusting circuit has the two MOS voltage variable capacitor elements, the back gate terminal of each MOS voltage variable capacitance element receives a control DC voltage via a respective one of level shift circuits, the voltage shift amount of one of the level shift circuits is established such that the corresponding MOS voltage variable capacitance element operates in a range where the C-V characteristic is linear in a range lower than the center voltage of the control DC voltage, and the voltage shift amount of the other of the level shift circuits is set such that the corresponding MOS voltage variable capacitance element operates in a range where the C-V characteristic is linear in a range higher than the center voltage of the control DC voltage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、水晶発振器、特に外部から供給する制御用の直流電圧値に基づいて発振周波数が変化する電圧制御型水晶発振器及び電圧制御型温度補償水晶発振器に関するものである。   The present invention relates to a crystal oscillator, and more particularly to a voltage-controlled crystal oscillator and a voltage-controlled temperature-compensated crystal oscillator whose oscillation frequency changes based on a control DC voltage value supplied from the outside.

近年、無線通信機器の局部発振器等の信号発生源としてＰＬＬ（Ｐｈａｓｅ Ｌｏｃｋ Ｌｏｏｐ；位相同期ループ）が広く用いられている。高精度のＰＬＬを実現するため、電圧制御発振器としてを水晶振動子を用いたものが一般的である。   In recent years, PLL (Phase Lock Loop) has been widely used as a signal generation source such as a local oscillator of a wireless communication device. In order to realize a high-accuracy PLL, a voltage controlled oscillator using a crystal resonator is generally used.

例えば、特開２００２−０２６６６０号公報にはインバータ素子を用いて構成した電圧制御型水晶発振器が開示されている。周知のように電圧制御型水晶発振器は共振ループの負荷容量を変化させることにより発振器の共振周波数が変化する現象を利用したものである。前出の公報ではインバータ素子を用い水晶発振器の共振ループ中に電圧可変容量素子を挿入し、電圧可変容量素子に印加する制御用直流電圧によって発振器が出力する周波数を制御している。   For example, Japanese Patent Application Laid-Open No. 2002-026660 discloses a voltage-controlled crystal oscillator configured using inverter elements. As is well known, the voltage-controlled crystal oscillator uses a phenomenon in which the resonance frequency of the oscillator changes by changing the load capacity of the resonance loop. In the above publication, an inverter element is used to insert a voltage variable capacitance element into the resonance loop of a crystal oscillator, and the frequency output from the oscillator is controlled by a control DC voltage applied to the voltage variable capacitance element.

一般的な電圧可変容量素子としては可変容量ダイオードが知られている。しかし、可変容量ダイオードは集積化が困難であることから発振回路を構成する他の部品と共にＩＣ化することができず、小型化や低コスト化の妨げとなっていた。
一方電圧可変容量素子としてＭＯＳ型電圧可変容量素子があり、集積化が容易なことから水晶発振器にも適用されつつある。（特開平１１−０８８０５２号公報） As a general voltage variable capacitance element, a variable capacitance diode is known. However, since variable capacitance diodes are difficult to integrate, they cannot be integrated with other components that constitute the oscillation circuit, which hinders miniaturization and cost reduction.
On the other hand, there is a MOS type voltage variable capacitance element as a voltage variable capacitance element, which is being applied to a crystal oscillator because of its easy integration. (Japanese Patent Laid-Open No. 11-088052)

図６はインバータ素子を用いた水晶発振器に、ＭＯＳ型電圧可変容量素子用いた温度補償回路と、ＭＯＳ型電圧可変容量素子用いた周波数調整回路とを付加した電圧制御型温度補償水晶発振器の一例を示す回路図である。
図中１は水晶振動子、Ｒ１ は帰還抵抗、２はインバータ素子、３（破線内）は温度補償回路、４（一点鎖線内）は周波数調整回路をそれぞれ示している。
ここで、周波数調整回路４は２つのＭＯＳ型電圧可変容量素子Ｄ１，Ｄ２と、２つのコンデンサＣ１，Ｃ２と、抵抗Ｒ２，Ｒ３とを備えたものである。 FIG. 6 shows an example of a voltage-controlled temperature compensated crystal oscillator in which a temperature compensation circuit using a MOS type voltage variable capacitance element and a frequency adjustment circuit using a MOS type voltage variable capacitance element are added to a crystal oscillator using an inverter element. FIG.
In the figure, reference numeral 1 denotes a crystal resonator, R1 denotes a feedback resistor, 2 denotes an inverter element, 3 (inside a broken line) denotes a temperature compensation circuit, and 4 (inside a one-dot chain line) denotes a frequency adjusting circuit.
Here, the frequency adjusting circuit 4 includes two MOS type voltage variable capacitance elements D1, D2, two capacitors C1, C2, and resistors R2, R3.

ＭＯＳ型電圧可変容量素子Ｄ１のゲート端子はコンデンサＣ１を介してインバータ素子２の入力端側に、ＭＯＳ型電圧可変容量素子Ｄ２のゲート端子はコンデンサＣ２を介してインバータ素子２の出力端側に夫々配置され、各ＭＯＳ型電圧可変容量素子のバックゲート端子は接地されている。そして外部制御電圧が各ＭＯＳ型電圧可変容量素子のゲート端子とコンデンサとの接続点に抵抗Ｒ２，Ｒ３を介してそれぞれ供給される。   The gate terminal of the MOS type voltage variable capacitance element D1 is on the input end side of the inverter element 2 via the capacitor C1, and the gate terminal of the MOS type voltage variable capacitance element D2 is on the output end side of the inverter element 2 via the capacitor C2. The back gate terminal of each MOS type voltage variable capacitance element is grounded. An external control voltage is supplied to the connection point between the gate terminal of each MOS type voltage variable capacitance element and the capacitor via resistors R2 and R3.

図７はＭＯＳ型電圧可変容量素子のゲート電圧と容量との関係（Ｃ−Ｖ特性）を示すものであり、ゲート電圧を変化させることによりＭＯＳ型電圧可変容量素子の容量値が変化することになる。このＭＯＳ型電圧可変容量素子はこの発振器の共振ループ中の負荷容量の一部を構成するものであるから、上述した原理に基づき外部制御電圧に応じた周波数変化を得ることができるのである。
特開２００２−０２６６６０号公報 特開平１１−０８８０５２号公報 FIG. 7 shows the relationship (CV characteristic) between the gate voltage and the capacitance of the MOS type voltage variable capacitance element, and the capacitance value of the MOS type voltage variable capacitance element changes by changing the gate voltage. Become. Since this MOS type voltage variable capacitance element constitutes a part of the load capacitance in the resonance loop of this oscillator, it is possible to obtain a frequency change according to the external control voltage based on the principle described above.
Japanese Patent Laid-Open No. 2002-026660 JP 11-088052 A

しかしながら、図７から明らかなようにＣ−Ｖ特性が直線的に変化する領域はごく僅かであり、この領域の両側ではゲート電圧の変化に対する容量の変化が徐々に鈍くなり曲線的な動作が現れてしまい、やがてゲート電圧を変化させても容量値は変化しない（飽和）領域に達するという特徴を持っている。
つまり、発振器の周波数可変量を大きくすることが困難であり、直線性の良い領域が少ないため使い勝手が悪いという欠点があった。
本発明は、外部から供給される制御電圧に応じた発振器の周波数可変量を大きくすると共に直線性の良い周波数変化を得ることを可能とした水晶発振器を提供することを目的とする。 However, as is apparent from FIG. 7, the region where the CV characteristic changes linearly is very small. On both sides of this region, the change in capacitance with respect to the change in gate voltage gradually becomes dull and a curvilinear operation appears. As a result, the capacitance value does not change even when the gate voltage is changed (saturation).
That is, it is difficult to increase the frequency variable amount of the oscillator, and there are disadvantages that the usability is poor because there are few regions with good linearity.
An object of the present invention is to provide a crystal oscillator capable of increasing the frequency variable amount of an oscillator according to a control voltage supplied from the outside and obtaining a frequency change with good linearity.

本発明は、少なくともインバータ素子と、水晶振動子と、ＭＯＳ型電圧可変容量素子を用いて構成した周波数調整回路と、を備えた水晶発振器に於いて、
前記周波数調整回路は、第１のＭＯＳ型電圧可変容量素子と第２のＭＯＳ型電圧可変容量素子とを有し、
第１のＭＯＳ型電圧可変容量素子のゲート端子はインバータ素子の入力端側に、第２のＭＯＳ型電圧可変容量素子のゲート端子はインバータ素子の出力端側に夫々配置され、
いずれか一方のＭＯＳ型電圧可変容量素子のゲート端子には直流バイアスが印加され、
各ＭＯＳ型電圧可変容量素子のバックゲート端子はコンデンサを介して接地され、
第１及び第２のＭＯＳ型電圧可変容量素子のバックゲート端子には夫々第１及び第２のレベルシフト回路を介して制御用直流電圧が供給されており、
前記レベルシフト回路の一方は前記制御用直流電圧の中心電圧より低い領域で一方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう、他方のレベルシフト回路は前記制御用直流電圧の中心電圧より高い領域で他方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう電圧のシフト量が設定されていることを特徴とするものである。 The present invention relates to a crystal oscillator including at least an inverter element, a crystal resonator, and a frequency adjustment circuit configured using a MOS voltage variable capacitance element.
The frequency adjustment circuit includes a first MOS type voltage variable capacitance element and a second MOS type voltage variable capacitance element,
The gate terminal of the first MOS type voltage variable capacitance element is arranged on the input end side of the inverter element, and the gate terminal of the second MOS type voltage variable capacitance element is arranged on the output end side of the inverter element, respectively.
A DC bias is applied to the gate terminal of one of the MOS type voltage variable capacitance elements,
The back gate terminal of each MOS type voltage variable capacitance element is grounded via a capacitor,
The control DC voltage is supplied to the back gate terminals of the first and second MOS type voltage variable capacitance elements via the first and second level shift circuits, respectively.
One of the level shift circuits operates one MOS type voltage variable capacitance element in a region where the CV characteristic is a straight line in a region lower than the central voltage of the control DC voltage, and the other level shift circuit performs the control The voltage shift amount is set so that the other MOS type voltage variable capacitance element operates in a region where the CV characteristic is a straight line in a region higher than the center voltage of the DC voltage for operation.

また、請求項２に係る発明は、少なくともインバータ素子と、水晶振動子と、ＭＯＳ型電圧可変容量素子を用いて構成した温度補償回路と、ＭＯＳ型電圧可変容量素子を用いて構成した周波数調整回路と、を備えた水晶発振器に於いて、
前記周波数調整回路は、第１のＭＯＳ型電圧可変容量素子と第２のＭＯＳ型電圧可変容量素子とを有し、
第１のＭＯＳ型電圧可変容量素子のゲート端子はインバータ素子の入力端側に、第２のＭＯＳ型電圧可変容量素子のゲート端子はインバータ素子の出力端側に夫々配置され、
いずれか一方のＭＯＳ型電圧可変容量素子のゲート端子には直流バイアスが印加され、
各ＭＯＳ型電圧可変容量素子のバックゲート端子はコンデンサを介して接地され、
第１及び第２のＭＯＳ型電圧可変容量素子のバックゲート端子には夫々第１及び第２のレベルシフト回路を介して制御用直流電圧が供給されており、
前記レベルシフト回路の一方は前記制御用直流電圧の中心電圧より低い領域で一方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう、他方のレベルシフト回路は前記制御用直流電圧の中心電圧より高い領域で他方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう電圧のシフト量が設定されていることを特徴とするものである。 According to a second aspect of the present invention, there is provided a temperature compensation circuit configured using at least an inverter element, a crystal resonator, a MOS voltage variable capacitance element, and a frequency adjustment circuit configured using a MOS voltage variable capacitance element. And a crystal oscillator comprising:
The frequency adjustment circuit includes a first MOS type voltage variable capacitance element and a second MOS type voltage variable capacitance element,
The gate terminal of the first MOS type voltage variable capacitance element is arranged on the input end side of the inverter element, and the gate terminal of the second MOS type voltage variable capacitance element is arranged on the output end side of the inverter element, respectively.
A DC bias is applied to the gate terminal of one of the MOS type voltage variable capacitance elements,
The back gate terminal of each MOS type voltage variable capacitance element is grounded via a capacitor,
The control DC voltage is supplied to the back gate terminals of the first and second MOS type voltage variable capacitance elements via the first and second level shift circuits, respectively.
One of the level shift circuits operates one MOS type voltage variable capacitance element in a region where the CV characteristic is a straight line in a region lower than the central voltage of the control DC voltage, and the other level shift circuit performs the control The voltage shift amount is set so that the other MOS type voltage variable capacitance element operates in a region where the CV characteristic is a straight line in a region higher than the center voltage of the DC voltage for operation.

また、請求項３に係る発明は、前記直流バイアスは前記温度補償回路と周波数調整回路との双方の基準電圧として用いられていることを特徴とするものである。   The invention according to claim 3 is characterized in that the DC bias is used as a reference voltage for both the temperature compensation circuit and the frequency adjustment circuit.

また、請求項４に係る発明は、前記制御用直流電圧の最小値をＶｍｉｎ、最大値をＶｍａｘ、中心電圧をＶｃｅｎｔｅｒとし、ＭＯＳ型電圧可変容量素子の容量が直線的に変化するゲート電圧の下限値をＶＧＢ１、上限値をＶＧＢ２とし、インバータ素子のしきい値をＶＤＤ／２とし、前記直流バイアスをＶｒｅｆとするとき、
直流バイアスを印加したＭＯＳ型電圧可変容量素子に制御電圧を供給するレベルシフト回路では制御用直流電圧がＶｃｅｎｔｅｒからＶｍａｘに変化するときにＶＤＤ／２−ＶＧＢ２からＶＤＤ／２−ＶＧＢ１に変化する電圧を出力するように、
他方のレベルシフト回路では制御用直流電圧がＶｍｉｎからＶｃｅｎｔｅｒに変化するときにＶｒｅｆ−ＶＧＢ２からＶｒｅｆ−ＶＧＢ１に変化する電圧を出力するように設定されていることを特徴とするものである。 According to a fourth aspect of the present invention, there is provided a gate in which the minimum value of the control DC voltage is V min , the maximum value is V max , the center voltage is V center, and the capacitance of the MOS type voltage variable capacitance element changes linearly. When the lower limit value of the voltage is V GB1 , the upper limit value is V GB2 , the threshold value of the inverter element is V DD / 2, and the DC bias is V ref ,
In a level shift circuit that supplies a control voltage to a MOS voltage variable capacitance element to which a DC bias is applied, when the control DC voltage changes from V center to V max , V DD / 2-V GB2 to V DD / 2-V To output a voltage that changes to GB1 ,
The other level shift circuit, characterized in that it is configured to output a voltage that changes from V ref -V GB2 to V ref -V GB1 when the control DC voltage changes from V min to V center Is.

本発明に係る水晶発振器は、制御電圧をレベルシフト回路を介して各ＭＯＳ型電圧可変容量素子に別個に供給するようにしたので、外部から供給される制御電圧に応じた発振器の周波数可変量を大きくすると共に直線性の良い周波数変化が得られるという利点がある。   In the crystal oscillator according to the present invention, the control voltage is separately supplied to each MOS type voltage variable capacitance element via the level shift circuit, so that the frequency variable amount of the oscillator according to the control voltage supplied from the outside can be set. There is an advantage that a frequency change with good linearity can be obtained while increasing the frequency.

以下本発明を実施例に基づき詳細に説明する。
図１は本発明に係る水晶発振器の実施形態例を示す回路図であって、図６にて示した回路図と共通する部分には同じ符号を付してその説明を省略する。
図６の従来の回路と異なる本発明の特徴点は周波数調整回路５の構成にある。
即ち、ＭＯＳ型電圧可変容量素子Ｄ１のゲート端子をインバータ素子の入力端側に、ＭＯＳ型電圧可変容量素子Ｄ２のゲート端子を直流カット用コンデンサＣｃを介してインバータ素子の出力端側に夫々配置すると共に、ＭＯＳ型電圧可変容量素子Ｄ１，Ｄ２のバックゲート端子をコンデンサＣａ，Ｃｂを介してそれぞれ接地し、ＭＯＳ型電圧可変容量素子Ｄ１，Ｄ２のバックゲート端子には夫々レベルシフト回路６，７を介して制御用直流電圧を供給するよう構成されているのである。 Hereinafter, the present invention will be described in detail based on examples.
FIG. 1 is a circuit diagram showing an embodiment of a crystal oscillator according to the present invention. The same reference numerals are given to the same parts as those in the circuit diagram shown in FIG.
A feature of the present invention that is different from the conventional circuit of FIG.
That is, the gate terminal of the MOS type voltage variable capacitance element D1 is arranged on the input end side of the inverter element, and the gate terminal of the MOS type voltage variable capacitance element D2 is arranged on the output end side of the inverter element via the DC cut capacitor Cc. At the same time, the back gate terminals of the MOS type voltage variable capacitance elements D1 and D2 are grounded via the capacitors Ca and Cb, respectively, and level shift circuits 6 and 7 are connected to the back gate terminals of the MOS type voltage variable capacitance elements D1 and D2, respectively. It is configured to supply a control DC voltage via this.

尚、このときＭＯＳ型電圧可変容量素子Ｄ２のゲート端子には直流バイアスＶｒｅｆを印加する。ちなみにこの直流バイアスＶｒｅｆは温度補償回路３の基準電圧源としても機能している。 At this time, a DC bias V ref is applied to the gate terminal of the MOS type voltage variable capacitance element D2. Incidentally, the DC bias V ref also functions as a reference voltage source for the temperature compensation circuit 3.

また、必要に応じて前記レベルシフト回路６，７の前段に制御用直流電圧の電圧値（振れ幅）を調整するためのゲイン調整部８を挿入しても良い。   Further, a gain adjusting unit 8 for adjusting a voltage value (amplitude) of the control DC voltage may be inserted before the level shift circuits 6 and 7 as necessary.

ここで、周波数調整回路５の動作について説明する。
図２はＭＯＳ型電圧可変容量素子のＣ−Ｖ特性を示す図であり、同図に示すように直線性の優れた領域を呈するゲート電圧の下限値をＶＧＢ１、上限値をＶＧＢ２と定義する。
また、前記制御用直流電圧の最小値をＶｍｉｎ、最大値をＶｍａｘ、中心電圧をＶｃｅｎｔｅｒとそれぞれ定義する。
更にインバータ素子２のしきい値をＶＤＤ／２と定義する。 Here, the operation of the frequency adjustment circuit 5 will be described.
FIG. 2 is a diagram showing CV characteristics of a MOS type voltage variable capacitance element. As shown in FIG. 2, the lower limit value of the gate voltage exhibiting a region having excellent linearity is defined as V GB1 and the upper limit value is defined as V GB2. To do.
Further, the minimum value of the control DC voltage is defined as V min , the maximum value is defined as V max , and the center voltage is defined as V center .
Further, the threshold value of the inverter element 2 is defined as V DD / 2.

図３は外部から供給される制御用直流電圧と、レベルシフト回路６、７からＭＯＳ型電圧可変容量素子Ｄ１，Ｄ２に供給される電圧ＶＣ１，ＶＣ２との関係を示す図であり、図４は外部から供給される制御用直流電圧と、ＭＯＳ型電圧可変容量素子のゲート電圧との関係を示す図である。
図３に示すように、ＭＯＳ型電圧可変容量素子Ｄ１に制御電圧を供給するレベルシフト回路では制御用直流電圧がＶｍｉｎからＶｃｅｎｔｅｒに変化するのに応じて（Ｖｒｅｆ−ＶＧＢ２）から（Ｖｒｅｆ−ＶＧＢ１）に変化する電圧を出力するように、ＭＯＳ型電圧可変容量素子Ｄ２に制御電圧を供給するレベルシフト回路では制御用直流電圧がＶｃｅｎｔｅｒからＶｍａｘに変化するときに（ＶＤＤ／２−ＶＧＢ２）から（ＶＤＤ／２−ＶＧＢ１）に変化する電圧を出力するように設定する。 FIG. 3 is a diagram showing the relationship between the control DC voltage supplied from the outside and the voltages VC1 and VC2 supplied from the level shift circuits 6 and 7 to the MOS type voltage variable capacitance elements D1 and D2. It is a figure which shows the relationship between the control DC voltage supplied from the outside, and the gate voltage of a MOS type voltage variable capacitance element.
As shown in FIG. 3, in the level shift circuit that supplies the control voltage to the MOS type voltage variable capacitance element D1, (V ref −V GB2 ) to (V ref −V GB2 ) in accordance with the change of the control DC voltage from V min to V center. In a level shift circuit that supplies a control voltage to the MOS type voltage variable capacitance element D2 so as to output a voltage that changes to V ref −V GB1 ), when the control DC voltage changes from V center to V max (V It is set to output a voltage changing from ( DD / 2−V GB2 ) to (V DD / 2−V GB1 ).

このようにレベルシフト回路を設定ことにより図４に示すように制御用直流電圧がＶｍｉｎからＶｃｅｎｔｅｒのときはＭＯＳ型電圧可変容量素子Ｄ１にＶＧＢ２からＶＧＢ１のゲート電圧が印加され、制御用直流電圧がＶｃｅｎｔｅｒからＶｍａｘのときはＭＯＳ型電圧可変容量素子Ｄ２にＶＧＢ２からＶＧＢ１のゲート電圧が印加される。
よって図５に示すように、従来よりも広い範囲で直線的な制御電圧ｖｓ周波数可変量の関係を得ることができる。 By setting the level shift circuit in this way, as shown in FIG. 4, when the control DC voltage is from V min to V center , the gate voltage from V GB2 to V GB1 is applied to the MOS type voltage variable capacitance element D1, and the control is performed. When the operating DC voltage is from V center to V max , the gate voltage from V GB2 to V GB1 is applied to the MOS type voltage variable capacitance element D2.
Therefore, as shown in FIG. 5, it is possible to obtain a linear control voltage vs. frequency variable amount relationship in a wider range than conventional.

要するに、本発明は前記レベルシフト回路の一方は前記制御用直流電圧の中心電圧より低い領域で一方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう、他方のレベルシフト回路は前記制御用直流電圧の中心電圧より高い領域で他方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう電圧のシフト量が設定されていることを特徴とするものである。
尚、上記の実施形態例では温度補償回路３を含んだものを示したが、この温度補償回路を省略した電圧制御型水晶発振器に本発明を適用してもよい。 In short, according to the present invention, one of the level shift circuits is operated so that one MOS type voltage variable capacitance element operates in a region where the CV characteristic is linear in a region lower than the central voltage of the control DC voltage. The shift circuit is characterized in that a voltage shift amount is set so that the other MOS type voltage variable capacitance element operates in a region where the CV characteristic is a straight line in a region higher than the central voltage of the control DC voltage. To do.
In the above embodiment, the one including the temperature compensation circuit 3 is shown. However, the present invention may be applied to a voltage controlled crystal oscillator in which the temperature compensation circuit is omitted.

本発明に係る水晶発振器の実施形態例を示す回路図。1 is a circuit diagram showing an embodiment of a crystal oscillator according to the present invention. ＭＯＳ型電圧可変容量素子のＣ−Ｖ特性を示す図。The figure which shows the CV characteristic of a MOS type voltage variable capacitance element. 制御用直流電圧とレベルシフト回路供給される電圧との関係を示す図The figure which shows the relationship between the control DC voltage and the voltage supplied to the level shift circuit 制御用直流電圧とＭＯＳ型電圧可変容量素子のゲート電圧との関係を示す図。The figure which shows the relationship between DC voltage for control, and the gate voltage of a MOS type voltage variable capacitance element. 制御電圧ｖｓ周波数可変量の関係を示す図。The figure which shows the relationship of control voltage vs frequency variable amount. 従来の水晶発振器の実施形態例を示す回路図Circuit diagram showing an embodiment of a conventional crystal oscillator ＭＯＳ型電圧可変容量素子のＣ−Ｖ特性を示す図。The figure which shows the CV characteristic of a MOS type voltage variable capacitance element.

符号の説明Explanation of symbols

１ 水晶振動子
２ インバータ素子
３ 温度補償回路
５ 周波数調整回路
６，７ レベルシフト回路
Ｄ１，Ｄ２ ＭＯＳ型電圧可変容量素子
Ｃａ，Ｃｂ コンデンサ
DESCRIPTION OF SYMBOLS 1 Crystal oscillator 2 Inverter element 3 Temperature compensation circuit 5 Frequency adjustment circuit 6, 7 Level shift circuit D1, D2 MOS type voltage variable capacitance element Ca, Cb Capacitor

Claims (4)

少なくともインバータ素子と、水晶振動子と、ＭＯＳ型電圧可変容量素子を用いて構成した周波数調整回路と、を備えた水晶発振器に於いて、
前記周波数調整回路は、第１のＭＯＳ型電圧可変容量素子と第２のＭＯＳ型電圧可変容量素子とを有し、
第１のＭＯＳ型電圧可変容量素子のゲート端子はインバータ素子の入力端側に、第２のＭＯＳ型電圧可変容量素子のゲート端子はインバータ素子の出力端側に夫々配置され、
いずれか一方のＭＯＳ型電圧可変容量素子のゲート端子には直流バイアスが印加され、
各ＭＯＳ型電圧可変容量素子のバックゲート端子はコンデンサを介して接地され、
第１及び第２のＭＯＳ型電圧可変容量素子のバックゲート端子には夫々第１及び第２のレベルシフト回路を介して制御用直流電圧が供給されており、
前記レベルシフト回路の一方は前記制御用直流電圧の中心電圧より低い領域で一方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう、他方のレベルシフト回路は前記制御用直流電圧の中心電圧より高い領域で他方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう電圧のシフト量が設定されていることを特徴とする水晶発振器。 In a crystal oscillator comprising at least an inverter element, a crystal resonator, and a frequency adjustment circuit configured using a MOS-type voltage variable capacitance element,
The frequency adjustment circuit includes a first MOS type voltage variable capacitance element and a second MOS type voltage variable capacitance element,
The gate terminal of the first MOS type voltage variable capacitance element is arranged on the input end side of the inverter element, and the gate terminal of the second MOS type voltage variable capacitance element is arranged on the output end side of the inverter element, respectively.
A DC bias is applied to the gate terminal of one of the MOS type voltage variable capacitance elements,
The back gate terminal of each MOS type voltage variable capacitance element is grounded via a capacitor,
The control DC voltage is supplied to the back gate terminals of the first and second MOS type voltage variable capacitance elements via the first and second level shift circuits, respectively.
One of the level shift circuits operates one MOS type voltage variable capacitance element in a region where the CV characteristic is a straight line in a region lower than the central voltage of the control DC voltage, and the other level shift circuit performs the control A crystal oscillator characterized in that a voltage shift amount is set so that the other MOS type voltage variable capacitance element operates in a region where the CV characteristic is a straight line in a region higher than the center voltage of the DC voltage for operation. 少なくともインバータ素子と、水晶振動子と、ＭＯＳ型電圧可変容量素子を用いて構成した温度補償回路と、ＭＯＳ型電圧可変容量素子を用いて構成した周波数調整回路と、を備えた水晶発振器に於いて、
前記周波数調整回路は、第１のＭＯＳ型電圧可変容量素子と第２のＭＯＳ型電圧可変容量素子とを有し、
第１のＭＯＳ型電圧可変容量素子のゲート端子はインバータ素子の入力端側に、第２のＭＯＳ型電圧可変容量素子のゲート端子はインバータ素子の出力端側に夫々配置され、
いずれか一方のＭＯＳ型電圧可変容量素子のゲート端子には直流バイアスが印加され、
各ＭＯＳ型電圧可変容量素子のバックゲート端子はコンデンサを介して接地され、
第１及び第２のＭＯＳ型電圧可変容量素子のバックゲート端子には夫々第１及び第２のレベルシフト回路を介して制御用直流電圧が供給されており、
前記レベルシフト回路の一方は前記制御用直流電圧の中心電圧より低い領域で一方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう、他方のレベルシフト回路は前記制御用直流電圧の中心電圧より高い領域で他方のＭＯＳ型電圧可変容量素子をＣ−Ｖ特性が直線となる領域で動作するよう電圧のシフト量が設定されていることを特徴とする水晶発振器。 In a crystal oscillator comprising at least an inverter element, a crystal resonator, a temperature compensation circuit configured using a MOS type voltage variable capacitance element, and a frequency adjusting circuit configured using a MOS type voltage variable capacitance element ,
The frequency adjustment circuit includes a first MOS type voltage variable capacitance element and a second MOS type voltage variable capacitance element,
The gate terminal of the first MOS type voltage variable capacitance element is arranged on the input end side of the inverter element, and the gate terminal of the second MOS type voltage variable capacitance element is arranged on the output end side of the inverter element, respectively.
A DC bias is applied to the gate terminal of one of the MOS type voltage variable capacitance elements,
The back gate terminal of each MOS type voltage variable capacitance element is grounded via a capacitor,
The control DC voltage is supplied to the back gate terminals of the first and second MOS type voltage variable capacitance elements via the first and second level shift circuits, respectively.
One of the level shift circuits operates one MOS type voltage variable capacitance element in a region where the CV characteristic is a straight line in a region lower than the central voltage of the control DC voltage, and the other level shift circuit performs the control A crystal oscillator characterized in that a voltage shift amount is set so that the other MOS type voltage variable capacitance element operates in a region where the CV characteristic is a straight line in a region higher than the center voltage of the DC voltage for operation. 前記直流バイアスは前記温度補償回路と周波数調整回路との双方の基準電圧として用いられていることを特徴とする請求項２に記載の水晶発振器。   3. The crystal oscillator according to claim 2, wherein the DC bias is used as a reference voltage for both the temperature compensation circuit and the frequency adjustment circuit. 前記制御用直流電圧の最小値をＶｍｉｎ、最大値をＶｍａｘ、中心電圧をＶｃｅｎｔｅｒとし、ＭＯＳ型電圧可変容量素子の容量が直線的に変化するゲート電圧の下限値をＶＧＢ１、上限値をＶＧＢ２とし、インバータ素子のしきい値をＶＤＤ／２とし、前記直流バイアスをＶｒｅｆとするとき、
直流バイアスを印加したＭＯＳ型電圧可変容量素子に制御電圧を供給するレベルシフト回路では制御用直流電圧がＶｃｅｎｔｅｒからＶｍａｘに変化するときにＶＤＤ／２−ＶＧＢ２からＶＤＤ／２−ＶＧＢ１に変化する電圧を出力するように、
他方のレベルシフト回路では制御用直流電圧がＶｍｉｎからＶｃｅｎｔｅｒに変化するときにＶｒｅｆ−ＶＧＢ２からＶｒｅｆ−ＶＧＢ１に変化する電圧を出力するように設定されていることを特徴とする請求項１乃至３の何れかに記載の水晶発振器。
The minimum value of the control DC voltage is V min , the maximum value is V max , the center voltage is V center , the lower limit value of the gate voltage at which the capacitance of the MOS type voltage variable capacitance element changes linearly is V GB1 , and the upper limit value. Is V GB2 , the threshold value of the inverter element is V DD / 2, and the DC bias is V ref ,
In a level shift circuit that supplies a control voltage to a MOS voltage variable capacitance element to which a DC bias is applied, when the control DC voltage changes from V center to V max , V DD / 2-V GB2 to V DD / 2-V To output a voltage that changes to GB1 ,
The other level shift circuit, characterized in that it is configured to output a voltage that changes from V ref -V GB2 to V ref -V GB1 when the control DC voltage changes from V min to V center The crystal oscillator according to claim 1.
JP2003380479A 2003-11-10 2003-11-10 Crystal oscillator Pending JP2007019565A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2003380479A JP2007019565A (en) 2003-11-10 2003-11-10 Crystal oscillator
PCT/JP2004/014964 WO2005046046A1 (en) 2003-11-10 2004-10-08 Crystal oscillator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2003380479A JP2007019565A (en) 2003-11-10 2003-11-10 Crystal oscillator

Publications (1)

Publication Number Publication Date
JP2007019565A true JP2007019565A (en) 2007-01-25

Family

ID=34567238

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2003380479A Pending JP2007019565A (en) 2003-11-10 2003-11-10 Crystal oscillator

Country Status (2)

Country Link
JP (1) JP2007019565A (en)
WO (1) WO2005046046A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103715988A (en) * 2012-09-28 2014-04-09 精工爱普生株式会社 Oscillation circuit, electronic apparatus, and moving object
JP2014072644A (en) * 2012-09-28 2014-04-21 Seiko Epson Corp Oscillation circuit, semiconductor integrated circuit device, vibration device, electronic apparatus and movable body
US9252789B2 (en) 2012-09-28 2016-02-02 Seiko Epson Corporation Oscillator circuit, vibratory device, electronic apparatus, moving object, method of adjusting vibratory device, and sensitivity adjustment circuit

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101133549B (en) * 2005-12-15 2011-03-23 旭化成电子材料元件株式会社 Voltage controlled oscillator, its design method and control voltage generation and application method
CN101110565B (en) * 2007-06-28 2010-04-14 安徽蓝盾光电子股份有限公司 Linearity correcting device for radar voltage controlled oscillator collecting vehicle information

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0645826A (en) * 1992-04-20 1994-02-18 Nec Corp Voltage controlled oscillator
WO1996003799A1 (en) * 1994-07-27 1996-02-08 Citizen Watch Co., Ltd. Temperature compensation type quartz oscillator
JPH1051238A (en) * 1996-07-30 1998-02-20 Asahi Kasei Micro Syst Kk Voltage control oscillator
JPH10303643A (en) * 1997-04-23 1998-11-13 Oki Electric Ind Co Ltd Voltage-controlled oscillation circuit
JP3266883B2 (en) * 1999-04-07 2002-03-18 東洋通信機株式会社 Piezoelectric oscillator
JP4089938B2 (en) * 2000-06-09 2008-05-28 日本電信電話株式会社 Voltage controlled oscillator
JP2002043842A (en) * 2000-07-26 2002-02-08 Oki Electric Ind Co Ltd Lc resonance circuit and voltage-controlled oscillator
JP2002135051A (en) * 2000-10-30 2002-05-10 Toyo Commun Equip Co Ltd Piezoelectric oscillator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103715988A (en) * 2012-09-28 2014-04-09 精工爱普生株式会社 Oscillation circuit, electronic apparatus, and moving object
JP2014072644A (en) * 2012-09-28 2014-04-21 Seiko Epson Corp Oscillation circuit, semiconductor integrated circuit device, vibration device, electronic apparatus and movable body
US9065383B2 (en) 2012-09-28 2015-06-23 Seiko Epson Corporation Oscillation circuit, semiconductor integrated circuit device, vibrating device, electronic apparatus, and moving object
US9106237B2 (en) 2012-09-28 2015-08-11 Seiko Epson Corporation Oscillation circuit, electronic apparatus, and moving object
US9252789B2 (en) 2012-09-28 2016-02-02 Seiko Epson Corporation Oscillator circuit, vibratory device, electronic apparatus, moving object, method of adjusting vibratory device, and sensitivity adjustment circuit

Also Published As

Publication number Publication date
WO2005046046A1 (en) 2005-05-19

Similar Documents

Publication Publication Date Title
US7474166B2 (en) PLL frequency synthesizer circuit and frequency tuning method thereof
US20100007427A1 (en) Switching capacitor generation circuit
JP2007300623A (en) Oscillation circuit with embedded power supply circuit
US7256660B2 (en) CMOS LC-tank oscillator
US7675374B2 (en) Voltage controlled oscillator with switching bias
US20090289732A1 (en) Semiconductor integrated circuit device and frequency synthesizer
KR100657839B1 (en) Delay cell tolerant of power noise
JP3921362B2 (en) Temperature compensated crystal oscillator
US6853262B2 (en) Voltage-controlled oscillator circuit which compensates for supply voltage fluctuations
US7268636B2 (en) Voltage controlled oscillator
US8222963B2 (en) Voltage-controlled oscillator
US20080303603A1 (en) Semiconductor integrated circuit device
EP1471632A2 (en) Oscillator circuit and oscillator
JP2007019565A (en) Crystal oscillator
US7944318B2 (en) Voltage controlled oscillator, and PLL circuit and radio communication device each including the same
US7394329B2 (en) Analog varactor
JP4539161B2 (en) Voltage controlled oscillator
JP2004056720A (en) Voltage controlled oscillator, high frequency receiver using the same, and high frequency transmitter
JP2012114679A (en) Voltage-controlled oscillator
JP4507070B2 (en) Communication device
KR100664867B1 (en) Voltage controlled oscillator
JP2002084135A (en) Voltage-controlled oscillator
JP2003258553A (en) Oscillation circuit
JP3656013B2 (en) Voltage controlled oscillator
JP4356759B2 (en) Surface acoustic wave oscillator and frequency variable method thereof