JP4314988B2 - Temperature compensated piezoelectric oscillator - Google Patents
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本発明は温度補償型SAW発振器に関し、特にSAW振動子の二次の周波数温度特性を補償するための回路を設けたSAW発振器に関する。 The present invention relates to a temperature-compensated SAW oscillator, and more particularly to a SAW oscillator provided with a circuit for compensating a secondary frequency temperature characteristic of a SAW vibrator.
近年、圧電発振器は周波数安定度、小型軽量、低価格等により通信機器や電子機器の多くの分野で用いられおり、中でも圧電振動子の周波数温度特性を補償した所謂温度補償型圧電発振器は、周波数の安定度を必要とする携帯電話等には不可欠のものである。また、最近、普及がめざましいリモートキーレス・エントリーシステムは、車や住居の鍵の開閉を容易にすると共に、送信信号を暗号化することでセキュリティ性も合わせ持つため、広く用いられるようになった。このリモートキーレス・エントリーシステムにも送信信号の精度を向上させるため、温度補償された圧電発振器が用いられているものがある。 In recent years, piezoelectric oscillators have been used in many fields of communication equipment and electronic equipment due to their frequency stability, small size, light weight, low price, etc. Among them, so-called temperature compensated piezoelectric oscillators that compensate the frequency temperature characteristics of piezoelectric vibrators It is indispensable for mobile phones and the like that require high stability. Recently, the remote keyless entry system, which has been remarkably popular, has been widely used because it makes it easy to open and close a car or a house key, and also has security by encrypting a transmission signal. Some remote keyless entry systems use a temperature-compensated piezoelectric oscillator in order to improve the accuracy of a transmission signal.
図5は特開2003−198250号公報に開示された温度補償型圧電発振器の回路構成を示す図であって、SAW振動子Y1と、コイルLと容量CとサーミスタThとからなるタンク回路TUと、増幅回路AMP1と、位相回路θと、増幅回路AMP2とから構成されている。SAW振動子Y1、タンク回路TU、増幅回路AMP1、位相回路θにより正帰還ループが形成されて発振が開始し、その発振周波数が増幅器AMP2介して出力される。増幅器AMP2は発振ループと出力との間の影響を低減するために設けたバッファ回路である。 FIG. 5 is a diagram showing a circuit configuration of the temperature compensated piezoelectric oscillator disclosed in Japanese Patent Application Laid-Open No. 2003-198250, and includes a tank circuit TU composed of a SAW vibrator Y1, a coil L, a capacitor C, and a thermistor Th. The amplifier circuit AMP1, the phase circuit θ, and the amplifier circuit AMP2. A positive feedback loop is formed by the SAW vibrator Y1, the tank circuit TU, the amplifier circuit AMP1, and the phase circuit θ to start oscillation, and the oscillation frequency is output through the amplifier AMP2. The amplifier AMP2 is a buffer circuit provided to reduce the influence between the oscillation loop and the output.
図5に示した温度補償型圧電発振器の特徴はタンク回路TUの動作にある。サーミスタThの抵抗値は、周知のように、温度の上昇に応じて小さくなる特性を有するので、タンク回路TUは、温度が低い場合は温度変化による伝達位相量の変化量が小さいのに対し、温度が高い場合は温度の変化による伝達位相量の変化が大きくなる。つまり、タンク回路TUを発振ループ内に設けることにより、広い温度範囲で発振周波数の温度変化を低減するが、特に高温域での温度変化を大幅に低減することが可能であると記述されている。 The feature of the temperature compensated piezoelectric oscillator shown in FIG. 5 is the operation of the tank circuit TU. As is well known, the resistance value of the thermistor Th has a characteristic of decreasing as the temperature rises. Therefore, when the temperature is low, the tank circuit TU has a small change amount of the transmission phase amount due to the temperature change. When the temperature is high, the change in the transmission phase amount due to the change in temperature becomes large. That is, it is described that by providing the tank circuit TU in the oscillation loop, the temperature change of the oscillation frequency can be reduced over a wide temperature range, but the temperature change particularly in a high temperature range can be significantly reduced. .
図6は特開2003−204260号公報に開示された温度補償型圧電発振器の回路構成を示す図であって、温度補償型圧電発振回路(TCXO)、位相比較回路、低域フィルタ、電圧制御型SAW発振回路(VCSO)及び分周回路を備えている。TCXOからはクロック信号S1出力され、位相比較回路に供給される。一方、分周回路はVCSOから出力されるクロック信号S4を分周して分周信号S5を出力する。分周回路の分周比1/Nは基準温度において分周信号S5の周波数がTCXOから出力されるクロック信号S1の周波数に等しくなる分周比に設定される。位相比較回路はクロック信号S1とクロック信号S5とを比較して得られた位相差信号S2を出力する。低域フィルタは位相差信号S2を平滑したものを制御信号S3としてVCSOに供給する。図6の回路構成により所謂PLL回路が構成され、数百MHzから数GHzの高周波数帯で高い周波数安定度を満たす温度補償型圧電発振器が構成できる。
解決しようとする問題点は、図5に示す回路を用いて構成した温度補償型SAW発振器では、高精度のリモートキーレス・エントリーシステムに使用するには周波数安定度が十分ではなく、図6に示す回路を用いて構成した温度補償型SAW発振器では、周波数安定度は十分であるものの上記システムに用いるには高価になり過ぎ、使用できない点である。 The problem to be solved is that the temperature compensated SAW oscillator configured using the circuit shown in FIG. 5 has insufficient frequency stability for use in a high-precision remote keyless entry system. A temperature-compensated SAW oscillator configured using a circuit has sufficient frequency stability, but is too expensive to be used in the above system and cannot be used.
本発明は、圧電振動子を有する電圧制御型圧電発振器と、前記電圧制御型圧電発振器に温度補償用の電圧を供給する温度補償電圧生成回路とを備えた温度補償型圧電発振器であって、前記温度補償電圧生成回路は、温度によって電圧出力が変動する温度検出回路と、第1及び第2の演算増幅器と、第1及び第2のカレントミラー回路と、第1及び第2の定電圧源と、第1及び第2の抵抗と、第1及び第2のトランジスタとを少なくとも備えており、前記第1の演算増幅器の正側入力には前記温度検出回路が接続され、前記第1の演算増幅器の負側入力には前記第1の抵抗を介して前記第1の定電圧源が接続され、前記第1の演算増幅器の出力は、前記第1のトランジスタのベースおよび前記第2のトランジスタのベースに接続され、前記第1のトランジスタのコレクタは、前記第1のカレントミラー回路の入力側回路に接続され、前記第2のトランジスタのコレクタは、前記第2のカレントミラー回路の入力側回路に接続され、前記第1の演算増幅器の前記負側入力と前記第1の抵抗との接続点は、前記第1のトランジスタのエミッタおよび前記第2のトランジスタのエミッタに接続され、前記第1のカレントミラー回路の出力側回路は、前記第2のカレントミラー回路の前記入力側回路に接続され、前記第2のカレントミラー回路の出力側回路は、前記第2の演算増幅器の負側入力に接続され、前記第2の演算増幅器の正側入力には前記第2の定電圧源が接続され、前記第2の演算増幅器の出力が前記第2の抵抗を介して前記第2の演算増幅器の前記負側入力に接続され、前記第2の演算増幅器の出力が前記温度補償電圧生成回路の出力となるよう構成され、前記第1の演算増幅器の前記負側入力と前記第1の抵抗との前記接続点の電圧が前記第1の定電圧源の電圧より大きい場合、前記第1のカレントミラー回路の前記入力側回路から前記第1のトランジスタを介して電流が供給され、前記接続点の前記電圧が前記第1の定電圧源の電圧より小さい場合、前記第1の定電圧源から前記第2のトランジスタを介して前記第2のカレントミラー回路の前記入力側回路に電流が供給される温度補償型圧電発振器である。 The present invention is a temperature-compensated piezoelectric oscillator comprising a voltage-controlled piezoelectric oscillator having a piezoelectric vibrator, and a temperature-compensated voltage generation circuit that supplies a voltage for temperature compensation to the voltage-controlled piezoelectric oscillator, The temperature compensation voltage generation circuit includes a temperature detection circuit whose voltage output fluctuates according to temperature, first and second operational amplifiers, first and second current mirror circuits, first and second constant voltage sources, , At least including first and second resistors, and first and second transistors, and the temperature detection circuit is connected to a positive input of the first operational amplifier, and the first operational amplifier The first constant voltage source is connected to the negative side input of the first operational amplifier via the first resistor, and the output of the first operational amplifier is the base of the first transistor and the base of the second transistor Connected to the first The collector of the transistor is connected to the input side circuit of the first current mirror circuit, the collector of the second transistor is connected to the input side circuit of the second current mirror circuit, and the first operational amplifier Is connected to an emitter of the first transistor and an emitter of the second transistor, and an output side circuit of the first current mirror circuit is The second current mirror circuit is connected to the input side circuit, and the second current mirror circuit output side circuit is connected to the negative side input of the second operational amplifier, and the second operational amplifier has a positive side. The second constant voltage source is connected to the side input, and the output of the second operational amplifier is connected to the negative input of the second operational amplifier through the second resistor, The output of the operational amplifier is configured to be the output of the temperature compensation voltage generation circuit, and the voltage at the connection point between the negative input of the first operational amplifier and the first resistor is the first constant. When the voltage is higher than the voltage of the voltage source, a current is supplied from the input side circuit of the first current mirror circuit via the first transistor, and the voltage at the connection point is the voltage of the first constant voltage source. When smaller, the temperature-compensated piezoelectric oscillator is configured such that a current is supplied from the first constant voltage source to the input side circuit of the second current mirror circuit through the second transistor .
本発明の温度補償型圧電発振器は、V字型特性する温度補償電圧生成回路を備えているため、周波数の温度補償もV字型特性とすることができるので、二次の周波数温度特性を有するSAW振動子と共に用いれば、高い周波数安定度の発振器を構成できるという利点と、温度補償電圧生成回路は容易にIC化が可能であり、温度補償型圧電発振器のコストを大幅に低減できるという利点がある。 Since the temperature-compensated piezoelectric oscillator of the present invention includes a temperature-compensated voltage generation circuit having a V-shaped characteristic, the frequency temperature compensation can also be a V-shaped characteristic, and thus has a secondary frequency temperature characteristic. When used with a SAW resonator, an oscillator with high frequency stability can be configured, and the temperature compensated voltage generation circuit can be easily integrated into an IC, and the cost of the temperature compensated piezoelectric oscillator can be greatly reduced. is there.
図1は本発明に係る温度補償型SAW発振器の実施の形態を示す回路図であって、温度変化を電圧変化に変換する温度補償回路αと、生成電圧を容量に変換する電圧−容量変換回路βと、SAW振動子と増幅器とからなるコルピッツ型発振回路γと、該発振回路γを制御(ON/OFF)する回路とから構成される。図1に示すコルピッツ型発振回路γは、トランジスタTrのコレクタ−ベース間の誘導性素子として、ベース−接地間にSAW振動子Y1、容量C3及びバラクタダイオードDvの直列接続素子を用いる。さらに、ベース−接地間に容量C1とC2との直列接続素子を接続すると共に、エミッタ−アース間に抵抗R2を挿入し、容量C1、C2の中点とエミッタとを接続して構成する。
また、電圧容量変換回路βは図1に示すように、抵抗R4の両端子にバラクタダイオードDvと容量C4との一端をそれぞれ接続し、他の端子を接地したπ型回路で、該回路と前記コルピッツ型発振回路γとにより電圧制御型発振回路が構成される。
FIG. 1 is a circuit diagram showing an embodiment of a temperature compensated SAW oscillator according to the present invention, in which a temperature compensation circuit α for converting a temperature change into a voltage change, and a voltage-capacitance conversion circuit for converting a generated voltage into a capacitor. β, a Colpitts oscillation circuit γ composed of a SAW vibrator and an amplifier, and a circuit for controlling (ON / OFF) the oscillation circuit γ. The Colpitts oscillation circuit γ shown in FIG. 1 uses a series connection element of a SAW vibrator Y1, a capacitor C3, and a varactor diode Dv between the base and the ground as an inductive element between the collector and the base of the transistor Tr. Further, a series connection element of capacitors C1 and C2 is connected between the base and the ground, and a resistor R2 is inserted between the emitter and the ground, and the midpoint of the capacitors C1 and C2 and the emitter are connected.
As shown in FIG. 1, the voltage-capacitance conversion circuit β is a π-type circuit in which one end of each of the varactor diode Dv and the capacitor C4 is connected to both terminals of the resistor R4 and the other terminal is grounded. The Colpitts oscillation circuit γ constitutes a voltage controlled oscillation circuit.
図2は、図1にブロック図で示した温度補償回路α(温度補償電圧生成回路)の構成を詳細に示す図であって、温度補償電圧生成回路αは、温度によって電圧出力が変動する温度検出回路と、第1及び第2の演算増幅器U1、U2と、第1及び第2のカレントミラー回路M1、M2と、第1及び第2の定電圧源V1、V2とを備えている。
第1の差動増幅器U1の+入力には、図2に示すように一方の端子を電源Vccに接続した抵抗R2の他方の端子を接続すると共に、ダイオードD1、D2を直列接続した複合ダイオードDの一方の端子を接続し、Dの他方の端子は接地した温度検出回路を接続する。第1の差動増幅器U1の−入力端子には抵抗R1を介して第1の定電源V1の+側と接続し、電源V1の−側を接地する。そして、第1の差動増幅器U1の出力とトランジスタQ1のベースを接続し、トランジスタQ1のエミッタとU1の−入力端子とを接続する。第1のカレントミラー回路M1のトランジスタQ3のコレクタと前記トランジスタQ1と接続すると共に、トランジスタQ3のコレクタとベースを導通する。トランジスタQ1のベースとトランジスタQ5のベースを接続すると共に、エミッタと第1の差動増幅器U1の−入力端子とを接続する。
FIG. 2 is a diagram showing in detail the configuration of the temperature compensation circuit α (temperature compensation voltage generation circuit) shown in the block diagram of FIG. 1. The temperature compensation voltage generation circuit α is a temperature at which the voltage output varies depending on the temperature. The detection circuit includes first and second operational amplifiers U1 and U2, first and second current mirror circuits M1 and M2, and first and second constant voltage sources V1 and V2.
The positive input of the first differential amplifier U1 is connected to the other terminal of the resistor R2 having one terminal connected to the power supply Vcc, as shown in FIG. 2, and a composite diode D in which diodes D1 and D2 are connected in series. The other terminal of D is connected to a grounded temperature detection circuit. The negative input terminal of the first differential amplifier U1 is connected to the positive side of the first constant power source V1 via the resistor R1, and the negative side of the power source V1 is grounded. Then, the output of the first differential amplifier U1 and the base of the transistor Q1 are connected, and the emitter of the transistor Q1 and the negative input terminal of U1 are connected. The collector of the transistor Q3 of the first current mirror circuit M1 is connected to the transistor Q1, and the collector and base of the transistor Q3 are made conductive. The base of the transistor Q1 and the base of the transistor Q5 are connected, and the emitter and the negative input terminal of the first differential amplifier U1 are connected.
さらに、トランジスタQ5のコレクタと、第1のカレントミラー回路M1のトランジスタQ4のコレクタと、第2のカレントミラー回路M2のトランジスタQ6のコレクタとを接続すると共に、トランジスタQ6のコレクタとベースとを導通する。第2のカレントミラー回路M2のトランジスタQ7のコレクタと第2の差動増幅器U2の−入力とを接続し、第2の定電源V2の+側を第2の差動増幅器U2の+入力に接続し、電源V2の−側を接地する。第2の差動増幅器U2の出力と−入力とを抵抗R3介して接続する。 Further, the collector of the transistor Q5, the collector of the transistor Q4 of the first current mirror circuit M1, and the collector of the transistor Q6 of the second current mirror circuit M2 are connected, and the collector and base of the transistor Q6 are made conductive. . The collector of the transistor Q7 of the second current mirror circuit M2 is connected to the negative input of the second differential amplifier U2, and the positive side of the second constant power supply V2 is connected to the positive input of the second differential amplifier U2. Then, the negative side of the power supply V2 is grounded. The output and second input of the second differential amplifier U2 are connected via a resistor R3.
図2に示す温度補償回路αの動作を図3、図4を用いて詳細に説明する。周知のように、圧電結晶を用いて構成したSAW共振子の温度−周波数特性(周波数温度特性とも言う)は一般に上に凸の逆U字型の曲線を呈する。例えば、図3の曲線A(一点鎖線)は補償回路の無いSAW共振子を用いた発振回路の温度−周波数特性例であり、頂点温度Tpを中心として低温になるに従って、あるいは高温になるに従って周波数が曲線的に低下する逆U字型曲線となる。そこで、本発明においては、図3の破線Bに示すように発振回路の周波数をV字型に制御することにより、曲線Aの周波数変動を相殺して、図3の実線Cに示すような温度変化に対して周波数変動を少なくした特性を得ている。図4(a)は図2に示したダイオードD1、D2を直列接続した複合ダイオードDの温度特性で、横軸は温度、縦軸は複合ダイオードDの両端の呈する電圧Vdである。この図より温度の上昇に伴い複合ダイオードDの両端の呈する電圧Vdは直線的に低下する。ここで、Tpは図1に示すSAW振動子Y1が呈する周波数温度特性の頂点温度Tpである。温度Tpで複合ダイオードDの両端の呈する電圧Vdの値をVdpとする。ここで、第1の定電源V1の電圧を電圧Vdpと等しく設定する。
いま、温度補償型SAW発振器の周囲温度Tが温度Tpより低い場合を想定すると、電圧VdすなわちV+はVdpより高い値となる。すると、差動増幅器の特性(差動増幅器の増幅度を無限大∞とすると、+入力の電圧V+と−入力の電圧V−が等しくなるように動作する)より、第1の差動増幅器U1の2つの入力端子はV+=V−となり、抵抗R1とトランジスタQ1のエミッタと第1の演算増幅器の−入力との接続点ではV−>Vdpとなるので、カレントミラー回路M1からトランジスタQ1を通して電流ILが供給されることになる。カレントミラー回路の特性より同じ電流ILがカレントミラー回路M1のトランジスタQ4を介して、トランジスタQ6に供給される。これに応じ、カレントミラー回路M2のトランジスタQ7にも電流ILが流れることになる。トランジスタQ7に流れる電流ILは第2の差動増幅器U2の抵抗R3を介してトランジスタQ7に供給されることになるから、第2の差動増幅器U2の出力電圧Vcontは電流ILに応じて変化することになる。
The operation of the temperature compensation circuit α shown in FIG. 2 will be described in detail with reference to FIGS. As is well known, the temperature-frequency characteristic (also referred to as frequency temperature characteristic) of a SAW resonator formed using a piezoelectric crystal generally exhibits an upwardly inverted U-shaped curve. For example, a curve A (dashed line) in FIG. 3 is an example of a temperature-frequency characteristic of an oscillation circuit using a SAW resonator without a compensation circuit, and the frequency becomes lower as the apex temperature Tp becomes lower or as the temperature becomes higher. Becomes an inverted U-shaped curve with a curvilinear drop. Therefore, in the present invention, by controlling the frequency of the oscillation circuit to be V-shaped as shown by the broken line B in FIG. 3, the frequency variation of the curve A is canceled out, and the temperature as shown by the solid line C in FIG. The characteristic that the frequency fluctuation is reduced with respect to the change is obtained. 4A shows the temperature characteristics of the composite diode D in which the diodes D1 and D2 shown in FIG. 2 are connected in series. The horizontal axis indicates the temperature, and the vertical axis indicates the voltage Vd exhibited across the composite diode D. FIG. From this figure, as the temperature rises, the voltage Vd exhibited across the composite diode D decreases linearly. Here, Tp is the apex temperature Tp of the frequency temperature characteristic exhibited by the SAW vibrator Y1 shown in FIG. The value of the voltage Vd presented across the composite diode D at the temperature Tp is Vdp. Here, the voltage of the first constant power supply V1 is set equal to the voltage Vdp.
Assuming that the ambient temperature T of the temperature compensated SAW oscillator is lower than the temperature Tp, the voltage Vd, that is, V + is higher than Vdp. Then, according to the characteristics of the differential amplifier (when the amplification factor of the differential amplifier is infinite ∞, the positive input voltage V + and the negative input voltage V− operate to be equal), the first differential amplifier U1. V + = V− and V−> Vdp at the connection point between the resistor R1, the emitter of the transistor Q1 and the first input of the first operational amplifier, so that the current from the current mirror circuit M1 through the transistor Q1. IL will be supplied. The same current I L from the characteristic of the current mirror circuit through the transistor Q4 of the current mirror circuit M1, is supplied to the transistor Q6. Accordingly, so that also the current I L flows through the transistor Q7 of the current mirror circuit M2. Since current I L flowing through the transistor Q7 is supplied to the transistor Q7 through the resistor R3 of the second differential amplifier U2, the output voltage Vcont of the second differential amplifier U2 in response to the current I L Will change.
次に温度補償型SAW発振器の周囲温度Tが温度Tpより高い場合を想定すると、複合ダイオードDの両端の電圧VdはVdpより下降し、V+=Vd<V1となる。抵抗R1とトランジスタQ1のエミッタの接続点の電圧V−はV−=V+<V1となるので、電源V1からトランジスタQ5を介して電流IHを供給する。該電流IHがトランジスタQ6に流れると、カレントミラー回路M2のトランジスタQ7を介して電流IHが流れることになる。トランジスタQ7に流れる電流IHは第2の差動増幅器U2の抵抗R3を介してトランジスタQ7に供給される。この電流を供給すべく第2の差動増幅器U2の出力電圧Vcontが上昇することになる。ここで、温度TがTpと等しい場合にはカレントミラー回路M1、M2とも電流が流れないので、第2の差動増幅器U2の出力電圧Vcontは第2の定電源V2の電圧値がそのまま出力されることになる。つまり、図2に示す温度補償回路αの出力電圧Vcontの温度特性は、図4(b)に示したように温度Tpで最小電圧V2を呈するV字型の電圧特性となる Next, assuming that the ambient temperature T of the temperature compensated SAW oscillator is higher than the temperature Tp, the voltage Vd across the composite diode D falls below Vdp, and V + = Vd <V1. Since the voltage V− at the connection point between the resistor R1 and the emitter of the transistor Q1 is V− = V + <V1, the current IH is supplied from the power supply V1 through the transistor Q5. When said current I H flows through the transistor Q6, so that the current flows I H through the transistor Q7 of the current mirror circuit M2. Current I H flowing through the transistor Q7 is supplied to the transistor Q7 through the resistor R3 of the second differential amplifier U2. In order to supply this current, the output voltage Vcont of the second differential amplifier U2 increases. Here, when the temperature T is equal to Tp, no current flows through the current mirror circuits M1 and M2, so that the output voltage Vcont of the second differential amplifier U2 is output as it is as the voltage value of the second constant power supply V2. Will be. That is, the temperature characteristic of the output voltage Vcont of the temperature compensation circuit α shown in FIG. 2 is a V-shaped voltage characteristic that exhibits the minimum voltage V2 at the temperature Tp as shown in FIG. 4B.
図1に示すバラクタダイオードDvの印加電圧(Vcont)−容量特性は、図3(c)に示すように電圧Vcontが増大するに応じて容量Cは減少する。いま、コルピッツ発振回路γの温度を一定にしておき、複合ダイオードDの周囲温度Tのみを変化さるとすると、コルピッツ発振回路γの周波数温度特性は図3(d)に示すように温度Tpを最小値とするV字型周波数特性となる。
図4はSAW振動子のみの周波数温度特性Aに、温度補償回路αによる周波数温度特性Bを加えることにより、温度補償後の本発明の温度補償型SAW発振器の周波数温度特性Cが得られる。
また、上述した回路はIC化が容易であり、温度補償型SAW発振器のコストを大幅に低減できる利点がある。
The applied voltage (Vcont) -capacitance characteristic of the varactor diode Dv shown in FIG. 1 decreases as the voltage Vcont increases as shown in FIG. 3 (c). Now, assuming that the temperature of the Colpitts oscillation circuit γ is kept constant and only the ambient temperature T of the composite diode D is changed, the frequency temperature characteristic of the Colpitts oscillation circuit γ has a minimum temperature Tp as shown in FIG. It becomes V-shaped frequency characteristic as a value.
In FIG. 4, the frequency temperature characteristic C of the temperature compensated SAW oscillator of the present invention after temperature compensation is obtained by adding the frequency temperature characteristic B by the temperature compensation circuit α to the frequency temperature characteristic A of only the SAW vibrator.
Further, the circuit described above can be easily integrated, and has the advantage that the cost of the temperature compensated SAW oscillator can be significantly reduced.
Tr、Q1、Q3、Q4、Q5、Q6、Q7 トランジスタ
Y1 圧電振動子
Dv バラクタ・ダイオード
R1、R2、R3、R4 抵抗
C1、C2、C3、C4、C5 容量
V1、V2 電源
D1、D2 ダイオード
U1、U2 差動増幅器
Vcont 差動増幅器の出力電圧
Vcc 電源
Tr, Q1, Q3, Q4, Q5, Q6, Q7 Transistor
Y1 Piezoelectric vibrator
Dv Varactor diodes R1, R2, R3, R4 Resistors C1, C2, C3, C4, C5 Capacitance V1, V2 Power supply D1, D2 Diode U1, U2 Differential amplifier Vcont Output voltage Vcc of differential amplifier
Claims (3)
前記温度補償電圧生成回路は、
温度によって電圧出力が変動する温度検出回路と、
第1及び第2の演算増幅器と、
第1及び第2のカレントミラー回路と、
第1及び第2の定電圧源と、
第1及び第2の抵抗と、
第1及び第2のトランジスタと
を少なくとも備えており、
前記第1の演算増幅器の正側入力には前記温度検出回路が接続され、
前記第1の演算増幅器の負側入力には前記第1の抵抗を介して前記第1の定電圧源が接続され、
前記第1の演算増幅器の出力は、前記第1のトランジスタのベースおよび前記第2のトランジスタのベースに接続され、
前記第1のトランジスタのコレクタは、前記第1のカレントミラー回路の入力側回路に接続され、
前記第2のトランジスタのコレクタは、前記第2のカレントミラー回路の入力側回路に接続され、
前記第1の演算増幅器の前記負側入力と前記第1の抵抗との接続点は、前記第1のトランジスタのエミッタおよび前記第2のトランジスタのエミッタに接続され、
前記第1のカレントミラー回路の出力側回路は、前記第2のカレントミラー回路の前記入力側回路に接続され、
前記第2のカレントミラー回路の出力側回路は、前記第2の演算増幅器の負側入力に接続され、
前記第2の演算増幅器の正側入力には前記第2の定電圧源が接続され、
前記第2の演算増幅器の出力が前記第2の抵抗を介して前記第2の演算増幅器の前記負側入力に接続され、
前記第2の演算増幅器の出力が前記温度補償電圧生成回路の出力となるよう構成され、
前記第1の演算増幅器の前記負側入力と前記第1の抵抗との前記接続点の電圧が前記第1の定電圧源の電圧より大きい場合、前記第1のカレントミラー回路の前記入力側回路から前記第1のトランジスタを介して電流が供給され、
前記接続点の前記電圧が前記第1の定電圧源の電圧より小さい場合、前記第1の定電圧源から前記第2のトランジスタを介して前記第2のカレントミラー回路の前記入力側回路に電流が供給されることを特徴とする温度補償型圧電発振器。 A temperature-compensated piezoelectric oscillator comprising a voltage-controlled piezoelectric oscillator having a piezoelectric vibrator, and a temperature-compensated voltage generation circuit that supplies a temperature-compensated voltage to the voltage-controlled piezoelectric oscillator,
The temperature compensation voltage generation circuit includes:
A temperature detection circuit whose voltage output varies depending on the temperature;
First and second operational amplifiers;
First and second current mirror circuits;
First and second constant voltage sources ;
First and second resistors;
A first and a second transistor;
At least,
The temperature detection circuit is connected to the positive input of said first operational amplifier,
Wherein said first constant voltage source through said first resistor is connected to the negative input of the first operational amplifier,
An output of the first operational amplifier is connected to a base of the first transistor and a base of the second transistor;
A collector of the first transistor is connected to an input side circuit of the first current mirror circuit;
A collector of the second transistor is connected to an input side circuit of the second current mirror circuit;
A connection point between the negative input of the first operational amplifier and the first resistor is connected to an emitter of the first transistor and an emitter of the second transistor,
The output circuit of the first current mirror circuit is connected to the input side circuit of the second current mirror circuit,
The output circuit of the second current mirror circuit is connected to the negative input of said second operational amplifier,
Wherein said second constant voltage source is connected to the positive input of the second operational amplifier,
The output of the second operational amplifier is connected to the negative input of said second operational amplifier via said second resistor,
Is configured so that the output of the second operational amplifier is an output of the temperature compensation voltage generation circuit,
When the voltage at the connection point between the negative input of the first operational amplifier and the first resistor is greater than the voltage of the first constant voltage source, the input circuit of the first current mirror circuit Current from the first transistor through the first transistor,
When the voltage at the connection point is smaller than the voltage of the first constant voltage source, a current flows from the first constant voltage source to the input side circuit of the second current mirror circuit through the second transistor. Is provided . A temperature-compensated piezoelectric oscillator, wherein
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