JP2008211757A - Temperature compensated piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a temperature compensated piezoelectric oscillator which compensates for a piezoelectric vibrator presenting a third-order curve over a wide temperature range and is a compensation circuit suitable for IC. <P>SOLUTION: The temperature compensated piezoelectric oscillator comprises: an oscillation circuit; a piezoelectric vibrator; and a first frequency temperature compensation circuit having first, second and third MOS capacitance elements. The first frequency temperature compensation circuit is a circuit connecting the second MOS capacitance element in parallel to a circuit connecting the first MOS capacitance element and the third MOS capacitance element in series. The temperature compensated piezoelectric oscillator supplies a reference voltage of which a voltage value is fixed, to a connecting point of one terminal of the first MOS capacitance element and one terminal of the second MOS capacitance element, supplies a first control voltage to a connecting point of another terminal of the first MOS capacitance element and one terminal of the third MOS capacitance element, and supplies a second control voltage to a connecting point of another terminal of the third MOS capacitance element and another terminal of the second MOS capacitance element. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a piezoelectric oscillator, and more particularly, to a temperature compensated piezoelectric oscillator that performs temperature compensation of a piezoelectric vibrator using a simple temperature compensation circuit and that is suitable for integration into an IC.

  Piezoelectric oscillators have excellent features such as frequency stability, small size, light weight, and low price, so they are used in many fields such as communication equipment and electronic equipment. Among them, temperature compensated piezoelectric oscillators that compensate the frequency temperature characteristics of piezoelectric vibrators (TCXO) is widely used in mobile phones and the like. As is well known, piezoelectric oscillators and Colpitts oscillators are often used for the circuit configuration of piezoelectric oscillators, but the basic circuit configuration is the same. When the AC grounding point is a Pierce oscillator, the emitter is grounded. In the case of a Colpitts type oscillation circuit, the difference is in the collector grounding.

  Patent Document 1 discloses a temperature compensated oscillator by the present applicant. FIG. 21 shows an example of a circuit configuration of the temperature compensated oscillator, which is a typical circuit in which a Colpitts oscillation circuit OSC1, a DC blocking capacitor C3, a temperature compensation circuit Comp, and a crystal resonator Xtal are connected in series. This is a temperature compensated crystal oscillator configured using a simple Colpitts oscillation circuit. As shown in FIG. 21, the Colpitts oscillation circuit OSC1 connects the collector of the transistor Tr1 to the power supply VCC, supplies a bias voltage to the base via the bleeder resistors R1 and R2, and connects the capacitor C1 between the base and the emitter. To do. Further, an emitter resistor Re and a capacitor C2 are connected in parallel between the emitter of the transistor Tr1 and the ground, and an oscillation output is taken out from the emitter through the capacitor Co. The collector of the transistor Tr1 is grounded at a high frequency via a bypass capacitor Cc.

In the temperature compensated oscillator shown in FIG. 21, a temperature compensation circuit Comp is connected to the base of the transistor TR1 via a DC blocking capacitor C3, and a crystal resonator Xtal is connected to the temperature compensation circuit Comp. The temperature compensation circuit Comp is composed of a circuit in which a low-temperature portion compensation MOS capacitor ML and a capacitor C4 are connected in series and a high-temperature portion compensation MOS capacitor MH in parallel, and the low-temperature portion MOS capacitor ML The high-temperature MOS capacitor element MH is connected in parallel with opposite polarities.
The low-temperature part control voltage VL is supplied to the connection point between the back gate of the low-temperature MOS capacitor ML and the capacitor C4 via the resistor R4, and the high-temperature part control is supplied to the gate of the high-temperature MOS capacitor MH via the resistor R5. A voltage VH is supplied. The reference voltage Vref is supplied to the connection point between the gate of the low-temperature MOS capacitor element ML and the back gate of the high-temperature MOS capacitor element MH via the resistor R6. As is well known, the MOS capacitance element is an element whose capacitance changes depending on the voltage applied between the back gate BG and the gate G. For example, when the gate G voltage is changed from a low value to a high value with reference to the back gate BG, the capacitance increases almost linearly, and at a sufficiently low or high voltage, the capacitance value is saturated and both are constant. It is a capacitive element that approaches the value.
JP 2004-343733 A

However, since the temperature compensation circuit disclosed in Patent Document 1 is configured so as to compensate the temperature in the low temperature region and the high temperature region using two MOS capacitors, respectively, as shown in FIG. Such an AT-cut crystal resonator in which the frequency temperature characteristic, that is, the frequency temperature characteristic is almost flat near the normal temperature, can be compensated, but there is a problem that the temperature compensation at both the low and high temperature ends is insufficient. Further, when an artificial quartz crystal is cut to obtain an AT-cut quartz plate with a predetermined angle, the angular distribution of the obtained quartz plate becomes a normal distribution with the predetermined angle as the center. Therefore, if only the cutting angle exhibiting the frequency-temperature characteristic of FIG. 22A is used, a cubic curve having a maximum value and a minimum value as shown in FIG. Alternatively, there has been a problem that a quartz base plate having a general cutting angle that rises to the right with respect to the temperature as shown in FIG.
The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a temperature-compensated piezoelectric oscillator which is improved in compensation accuracy over a wide temperature range and suitable for IC implementation.

In order to achieve the above object, the present invention provides a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series, the frequency temperature compensation circuit comprising: A circuit comprising a second and a third MOS capacitive element, wherein the second MOS capacitive element is connected in parallel to a circuit in which the first MOS capacitive element and the third MOS capacitive element are connected in series, and one terminal of the first MOS capacitive element; A reference voltage having a constant voltage value is supplied to a connection point between the first MOS capacitor element and one terminal of the second MOS capacitor element, and a connection point between the other terminal of the first MOS capacitor element and one terminal of the third MOS capacitor element The first control voltage is supplied to the second MOS capacitor element, and the second control voltage is supplied to a connection point between the other terminal of the third MOS capacitor element and the other terminal of the second MOS capacitor element.
When the temperature compensated piezoelectric oscillator is configured in this way, it becomes possible to compensate for a cubic-shaped piezoelectric vibrator having a frequency temperature characteristic having a maximum value and a minimum value, and a low temperature range, a normal temperature range, and a high temperature range with respect to the temperature. Thus, the temperature compensation is performed separately using two linearly varying voltages, and therefore, there is an effect that the compensation can be made with accuracy over a wide temperature range.

The present invention is also a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series, wherein the frequency temperature compensation circuit includes first, second, and third MOS capacitors. A circuit comprising an element and a first capacitor, a circuit in which the second MOS capacitor element is connected in parallel to a circuit in which the first MOS capacitor element and the first capacitor are connected in series, and a circuit in which the third MOS capacitor element is connected in series A reference voltage having a constant voltage value is supplied to a connection point between one terminal of the first MOS capacitor element and one terminal of the second MOS capacitor element, and the other terminal of the first MOS capacitor element and the terminal A first control voltage is supplied to a connection point between one terminal of the first capacitor and one terminal of the third MOS capacitor element, and the other terminal of the third MOS capacitor element and the other terminal of the first capacitor are supplied. Terminal It is configured to supply the second control voltage to the connection point between the other terminal of the first 2MOS capacitive element.
By constructing a temperature-compensated piezoelectric oscillator in this way, it is possible to appropriately compensate for a piezoelectric vibrator whose frequency-temperature characteristic exhibits a cubic curve, and separately compensates for the low temperature range, the normal temperature range, and the high temperature range. There is an effect that compensation can be made with accuracy over a range.

The present invention is also a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series, wherein the frequency temperature compensation circuit includes first, second, and third MOS capacitors. A circuit comprising: an element; and first and second capacitive elements, wherein the first MOS capacitive element and the first capacitor are connected in series, the second capacitor and a third MOS capacitive element are connected in series, and the first A circuit in which two MOS capacitor elements are connected in parallel, and a voltage value is constant at a connection point between one terminal of the first MOS capacitor element, one terminal of the second capacitor, and one terminal of the second MOS capacitor element. A reference voltage is supplied, a connection point between the other terminal of the first MOS capacitor and one terminal of the first capacitor, and the other terminal of the second capacitor and one terminal of the third MOS capacitor. To the connection point A first control voltage is supplied, and a second control voltage is supplied to a connection point between the other terminal of the first capacitor, the other terminal of the third MOS capacitor element, and the other terminal of the second MOS capacitor element. It is configured as follows.
By constructing a temperature-compensated piezoelectric oscillator in this way, it is possible to appropriately compensate for a piezoelectric vibrator whose frequency-temperature characteristic exhibits a cubic curve, and separately compensates for the low temperature range, the normal temperature range, and the high temperature range. There is an effect that compensation can be made with accuracy over a range.

The present invention is also a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series, wherein the frequency temperature compensation circuit includes first, second, and third MOS capacitors. And a first connection circuit of the first MOS capacitor and the first capacitor, and the second capacitor, the third MOS capacitor, and the third capacitor. A series connection circuit and a circuit in which the second MOS capacitor element is connected in parallel, and a connection point between one terminal of the first MOS capacitor element, one terminal of the second capacitor, and one terminal of the second MOS capacitor element Is supplied with a reference voltage having a constant voltage value, a connection point between the other terminal of the first MOS capacitor element and one terminal of the first capacitor, and the other terminal of the second capacitor and the third MOS capacitor. Connection to one terminal of the element A first control voltage, and a connection point between the other terminal of the third MOS capacitor element and one terminal of the third capacitor, and the other terminal of the first capacitor and the other terminal of the third capacitor. A second control voltage is supplied to a connection point between the terminal and the other terminal of the second MOS capacitor.
By constructing a temperature-compensated piezoelectric oscillator in this way, it is possible to appropriately compensate for a piezoelectric vibrator whose frequency-temperature characteristic exhibits a cubic curve, and separately compensates for the low temperature range, the normal temperature range, and the high temperature range. There is an effect that compensation can be made with accuracy over a range.

The present invention is also a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series, wherein the frequency temperature compensation circuit includes first, second, and third MOS capacitors. An element, first and second capacitors, and gain adjustable first and second amplifiers, wherein the first MOS capacitor, the first capacitor, the third MOS capacitor, and the second capacitor are connected in series. And a circuit in which the second MOS capacitor element is connected in parallel, and a voltage value is constant at a connection point between one terminal of the first MOS capacitor element and one terminal of the second MOS capacitor element. A voltage is supplied, a first control voltage is supplied to a connection point between the other terminal of the first MOS capacitor and one terminal of the first capacitor, and the other terminal of the first capacitor and the third MOS capacitor At the connection point with one of the terminals Supplying a first control voltage via one amplifier, and supplying a second control voltage via a second amplifier to a connection point between the other terminal of the third MOS capacitor and one terminal of the second capacitor; A second control voltage is supplied to a connection point between the other terminal of the second capacitor and the other terminal of the second MOS capacitor element.
When the temperature compensated piezoelectric oscillator is configured in this way, the voltage applied to the gate and the back gate of the third MOS capacitor can be appropriately set by the first and second amplifiers, so that the piezoelectric vibrator whose frequency-temperature characteristic exhibits a cubic curve can be obtained. In particular, the compensation can be made appropriately in the normal temperature range, and the low temperature range, the normal temperature range, and the high temperature range are separately compensated for temperature, so that there is an effect that the compensation can be made accurately over a wide temperature range.

The present invention is also a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series, wherein the frequency temperature compensation circuit includes first, second, and third MOS capacitors. The frequency temperature compensation circuit includes a first MOS capacitor element and a first capacitor connected in series. A circuit, a series connection circuit of the second capacitor, the third MOS capacitor element, and the third capacitor, and a circuit in which the second MOS capacitor element is connected in parallel, and one terminal of the first MOS capacitor element and the first capacitor A reference voltage having a constant voltage value is supplied to a connection point between one terminal of two capacitors and one terminal of the second MOS capacitor element, and one terminal of the first capacitor and the other terminal of the first MOS capacitor element is supplied. The first connection point to the terminal A control voltage is supplied, a first control voltage is supplied via a first amplifier to a connection point between the other terminal of the second capacitor and one terminal of the third MOS capacitor element, and the other of the third MOS capacitor element is supplied. A second control voltage is supplied via a second amplifier to a connection point between the terminal of the first capacitor and the one terminal of the third capacitor, and the other terminal of the first capacitor, the other terminal of the third capacitor, and the first capacitor. The second control voltage is supplied to a connection point with the other terminal of the 2MOS capacitor.
When the temperature compensated piezoelectric oscillator is configured in this way, the voltage applied to the gate and the back gate of the third MOS capacitor can be appropriately set by the first and second amplifiers, so that the piezoelectric vibrator whose frequency-temperature characteristic exhibits a cubic curve can be obtained. In particular, the compensation can be made appropriately in the normal temperature range, and the low temperature range, the normal temperature range, and the high temperature range are separately compensated for temperature, so that there is an effect that the compensation can be made accurately over a wide temperature range.

The present invention is also a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series, wherein the frequency temperature compensation circuit includes first, second, and third MOS capacitors. The frequency temperature compensation circuit is a circuit in which the first MOS capacitor element and the first capacitor are connected in series. A circuit in which the second MOS capacitor element is connected in parallel and a circuit in which the second capacitor and the third MOS capacitor element are connected in series are connected in series, and one terminal of the first MOS capacitor element and the first MOS capacitor element A reference voltage having a constant voltage value is supplied to a connection point with one terminal of the 2MOS capacitor element, and a first control is performed at a connection point between the other terminal of the first MOS capacitor element and one terminal of the first capacitor. Supplying a voltage, said first A second control voltage is supplied to a connection point between the other terminal of the quantity, one terminal of the second capacitor, and the other terminal of the second MOS capacitor, and the other terminal of the second capacitor and the third MOS capacitor A second control voltage is supplied to a connection point with one terminal of the element via a second amplifier, and a first control voltage is supplied to the other terminal of the third MOS capacitor element via the first amplifier. Has been.
When the temperature compensated piezoelectric oscillator is configured in this way, the voltage applied to the gate and the back gate of the third MOS capacitor can be appropriately set by the first and second amplifiers, so that the piezoelectric vibrator whose frequency-temperature characteristic exhibits a cubic curve can be obtained. In particular, the compensation can be made appropriately in the normal temperature range, and the low temperature range, the normal temperature range, and the high temperature range are separately compensated for temperature, so that there is an effect that the compensation can be made accurately over a wide temperature range.

The present invention is also a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series, wherein the frequency temperature compensation circuit includes first, second, and third MOS capacitors. An element, first and second capacitors, gain adjustable first and second amplifiers, first and second switches, and first and second reference voltages, and the frequency temperature compensation circuit includes: A circuit in which the second MOS capacitor element is connected in parallel to a circuit in which the first MOS capacitor element and the first capacitor are connected in series, and a circuit in which the second capacitor and the third MOS capacitor element are connected in series are connected in series. A reference voltage having a constant voltage value is supplied to a connection point between one terminal of the first MOS capacitor element and one terminal of the second MOS capacitor element, and the other terminal of the first MOS capacitor element. And one end of the first capacitor The first control voltage is supplied to the connection point between the first capacitor and the second control voltage at the connection point between the other terminal of the first capacitor, the one terminal of the second capacitor, and the other terminal of the second MOS capacitor element. And supplying an output of the second amplifier to a connection point between the other terminal of the second capacitor and one terminal of the third MOS capacitor element, and one of the second control voltage and the second reference voltage. Is selected by the second switch and supplied to the input of the second amplifier, the output of the first amplifier is connected to the other terminal of the third MOS capacitor, and the first control voltage and One of the first reference voltages is selected by the first switch and supplied to the input of the first amplifier.
When the temperature compensated piezoelectric oscillator is configured as described above, when the first and second switches are moved to the first and second control voltage sides, the voltages applied to the gate and the back gate of the third MOS capacitor element are changed to the first and second voltages. Since it can be set as appropriate by the amplifier, the piezoelectric vibrator whose frequency-temperature characteristic exhibits a cubic curve can be compensated appropriately especially in the normal temperature range, and the low temperature range, the normal temperature range, and the high temperature range are separately compensated for temperature. There is an effect that compensation can be made with high accuracy over a temperature range. Further, when the first and second switches are tilted to the first and second reference voltage sides, the third MOS capacitor element has a fixed capacitance, and there is an effect that it is possible to compensate for a piezoelectric vibrator having a flat near room temperature.

According to the present invention, the piezoelectric vibrator is a crystal vibrator, and the frequency temperature characteristic of the crystal vibrator is flat around normal temperature, a characteristic having a maximum value and a minimum value across an inflection point, or a temperature increase. In contrast, it is configured to cope with any of the characteristics of rising to the right.
When the temperature compensated piezoelectric oscillator is configured in this way, there is an effect that a quartz crystal resonator formed by cutting an AT cut substrate with a predetermined accuracy can be used efficiently.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of a temperature compensated piezoelectric oscillator according to a first embodiment of the present invention. The temperature compensated piezoelectric oscillator is a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit OSC, a piezoelectric vibrator Xtal, a first frequency temperature compensation circuit Comp1, and a capacitor C3 in series. The oscillation circuit OSC connects the collector of the transistor Tr1 to the power supply VCC via the resistor R1, and connects the resistor R2 between the base and the collector to form a self-bias circuit. This is a Colpitts oscillation circuit in which a capacitor C1 is connected between the base and emitter of the transistor Tr1, and an emitter resistor R3 and a capacitor C2 are connected in parallel between the emitter and the ground. The Colpitts type oscillation circuit OSC is also a well-known circuit like the Colpitts type oscillation circuit OSC1 (current feedback bias) of FIG. Further, as the piezoelectric vibrator Xtal, for example, as shown in FIG. 22B, a general AT cut crystal vibrator having a maximum value and a minimum value and exhibiting a cubic curve is used, and a capacitance C3 is used. A normal capacity is used.

  The first frequency temperature compensation circuit Comp1 is a circuit in which a first MOS capacitor element M1 and a third MOS capacitor element M3 are connected in series, and a second MOS capacitor element M2 having a polarity opposite to that of the first MOS capacitor element M1 is connected in parallel. It is. Then, a reference voltage Vref having a constant voltage value is supplied to the connection point between the gate of the first MOS capacitor element M1 and the back gate of the second MOS capacitor element M2 via the resistor R4. The first control voltage VL is supplied to the connection point between the back gate of the first MOS capacitor element M1 and the gate of the third MOS capacitor element M3 via the resistor R5, and the back gate of the third MOS capacitor element M3 and the second MOS capacitor element The second control voltage VH is supplied to the connection point of the gate of M2 via the resistor R6. Here, the reference voltage Vref, the first control voltage VL, and the second control voltage VH are supplied from a known circuit (not shown).

FIG. 2 is an example of a voltage difference Vd-capacitance C characteristic showing the relationship between the back gate-gate voltage difference Vd and the capacitance C with reference to the back gate voltage of the MOS capacitance element. FIG. 3 is an example showing the relationship between the reference voltage Vref, the first control voltage VL and the second control voltage VH used for temperature compensation, and the temperature T. The reference voltage Vref is always constant regardless of the temperature, and the relationship between the first control voltage VL and the temperature T decreases linearly between the low temperature and the normal temperature as shown by the solid line in FIG. In the meantime, a circuit configuration (not shown) is performed so that a constant value is maintained with a minimum value. In addition, the relationship between the second control voltage VH and the temperature T is constant at a minimum value between the low temperature and the normal temperature, and increases linearly between the normal temperature and the high temperature, as shown by the broken line in FIG. A circuit configuration (not shown) is performed.
The following describes how the capacitance C of the first MOS capacitor element M1 shown in FIG. 1 changes when the temperature T changes from a low temperature to a high temperature. The first control voltage VL is applied to the back gate of the first MOS capacitor element M1, and the reference voltage Vref is applied to the gate. When the first control voltage VL changes as shown in FIG. 3, the voltage difference Vd between the back gate and the gate increases linearly from around 0 V when the temperature changes from low temperature to normal temperature. It becomes the maximum in the vicinity and keeps the maximum value from room temperature to high temperature. When the variation of the voltage difference Vd is applied to the voltage difference Vd-capacitance C characteristic of FIG. 2, the variation of the capacitance C corresponds to the variation of the region indicated by α in FIG. That is, the relationship between the capacitance C and the temperature T of the first MOS capacitor element M1 shown in FIG. 1 is as shown by the curve shown in FIG.

Next, the relationship between the capacitance C of the second MOS capacitive element M2 shown in FIG. The voltage difference Vd between the back gate and the gate of the second MOS capacitor M2 is a negative value (the back gate voltage is higher than the gate voltage), and the voltage difference Vd is a negative constant value when the temperature changes from low temperature to room temperature. It becomes. When the temperature changes from room temperature to high temperature, the absolute value of the voltage difference Vd decreases linearly. When the fluctuation of the voltage difference Vd is applied to the curve of FIG. 2, it corresponds to the change of the region indicated by β. That is, the relationship between the capacitance C and the temperature T of the second MOS capacitive element M2 shown in FIG. 1 is as shown by the curve shown in FIG.
Next, the relationship between the capacitance C and the temperature T of the third MOS capacitive element M3 shown in FIG. 1 will be described. The second control voltage VH is applied to the back gate of the third MOS capacitive element M3, and the first control voltage VL is applied to the gate. When the first and second control voltages VL and VH change as shown in FIG. 3 with respect to the change in the temperature T, the voltage difference Vd between the back gate and the gate of the third MOS capacitor M3 is from the low temperature T. When it changes to room temperature, it decreases linearly with a positive value, and when the temperature T changes from room temperature to high temperature, its absolute value increases linearly with a negative value. When the fluctuation of the voltage difference Vd is applied to FIG. 2, it corresponds to the central portion (straight line portion) of the curve of FIG. That is, the relationship between the capacitance C of the third MOS capacitor element M3 and the temperature T is as shown by the curve shown in FIG.

  FIG. 5 is a diagram showing the relationship between the temperature T and the frequency deviation df / f. Assuming an ideal piezoelectric vibrator Xi whose frequency does not change with respect to changes in temperature T, the load capacity of this piezoelectric vibrator Xi is a capacitance C having temperature characteristics as shown in FIGS. Shall be connected in series. The frequency temperature characteristics at this time are frequency temperature characteristics as shown in FIGS. A circuit configured by connecting a second MOS capacitor element M2 in parallel to a circuit in which a first MOS capacitor element M1 and a third MOS capacitor element M3 are connected in series, like the first frequency temperature compensation circuit Comp1 shown in FIG. The frequency-temperature characteristic when the load capacity of the piezoelectric vibrator Xi is used is as shown in FIG. That is, the temperature characteristic of the first MOS capacitor element M1 is mainly at low temperatures, the temperature characteristic of the third MOS capacitor element M3 is mainly at temperatures near room temperature, and the temperature characteristic of the second MOS capacitor element M2 is mainly at high temperatures. The frequency-temperature characteristics are as shown in FIG. This characteristic corresponds to the inverse characteristic of the frequency temperature characteristic of the normal AT-cut crystal resonator shown in FIG. Therefore, if an AT-cut quartz crystal whose frequency temperature characteristic is as shown in FIG. 22B is used instead of the piezoelectric vibrator Xi, a frequency change due to temperature is compensated, and a flat temperature compensated crystal oscillator in a wide temperature range is obtained. can get.

The above description qualitatively describes the temperature characteristics of the frequency temperature compensation circuit Comp1 of FIG. 1, but in actual design, the voltage difference Vd-capacitance C curve of the MOS capacitance element shown in FIG. 2 and FIG. The relationship between the reference voltage Vref, the first control voltage VL and the second control voltage VH, and the temperature T is expressed by a mathematical expression, and is repeatedly obtained using a simulator until the frequency temperature characteristic of the temperature compensated piezoelectric oscillator converges within a desired deviation. . In this case, the temperature characteristics of the transistor Tr1 are also taken into consideration.
A feature of the present invention is that two voltages which are supplied from the voltage generation circuit and change linearly with respect to temperature, that is, the first control voltage VL and the second control voltage VH are used, and the capacitance of a specific region of the MOS capacitor element. Using the change, frequency temperature compensation is performed in three regions of low temperature, normal temperature, and high temperature. Therefore, there is an advantage that good compensation is possible in a wide temperature range, and the compensation circuit is simple, so that it is easy to make an IC.

  FIG. 6 is a circuit diagram showing the configuration of the temperature compensated piezoelectric oscillator of the second embodiment, and includes an oscillation circuit OSC, a piezoelectric vibrator Xtal, a second frequency temperature compensation circuit Comp2, and a capacitor C3. A temperature-compensated piezoelectric oscillator is configured in series connection. Since the oscillation circuit OSC, the piezoelectric vibrator Xtal, and the capacitor C3 are the same as those of the temperature compensated piezoelectric oscillator of the first embodiment shown in FIG. 1, the frequency temperature compensation circuit will be mainly described below. The second frequency temperature compensation circuit Comp2 includes a circuit in which a first MOS capacitor element M1 and a first capacitor C4 are connected in series to a circuit in which a first MOS capacitor element M1 and a second MOS capacitor element M2 having a reverse polarity are connected in parallel. This is a circuit in which a third MOS capacitor element M3 having the same polarity as the second MOS capacitor element is connected in series. A reference voltage Vref having a constant voltage value is supplied to a connection point between the gate of the first MOS capacitor element M1 and the back gate of the second MOS capacitor element M2 via the resistor R4. Further, the first control voltage VL is supplied to the connection point between the back gate of the first MOS capacitor M1 and the first capacitor C4 via the resistor R5, and the first MOS voltage element M3 is supplied to the gate via the resistor R8. A control voltage VL is supplied. The second control voltage VH is supplied via a resistor R7 to a connection point between the back gate of the third MOS capacitor element M3, the first capacitor C4, and the gate of the second MOS capacitor element M2.

  The frequency temperature compensation circuit Comp2 of the second embodiment is different from the first embodiment shown in FIG. 1 in that the third MOS capacitor element M3 is replaced with the first capacitor C4, and the third MOS capacitor element M3 is replaced from the parallel circuit. Is configured to be connected in series. The reference voltage Vref is applied to the gate of the first MOS capacitor element M1, the first control voltage VL is applied to the back gate, and the relationship between the temperature T and the capacitor C is the same as the temperature T-capacitance C characteristic of FIG. become. The second MOS capacitor element M2 is the same as that shown in FIG. The first control voltage VL is applied to the gate of the third MOS capacitor element M3, the second control voltage VH is applied to the back gate, and the relationship between the temperature T and the capacitance C is the temperature T-capacitance C characteristic of FIG. It will be the same.

FIG. 7 is a circuit diagram showing the configuration of the temperature compensated piezoelectric oscillator of the third embodiment, and includes an oscillation circuit OSC, a piezoelectric vibrator Xtal, a third frequency temperature compensation circuit Comp3, and a capacitor C3. A temperature-compensated piezoelectric oscillator is configured in series connection. The third frequency temperature compensation circuit Comp3 includes a circuit in which the first MOS capacitor element M1 and the first capacitor C4 are connected in series, a circuit in which the second capacitor C5 and the third MOS capacitor element M3 are connected in series, a first MOS capacitor element, This is a circuit in which a second MOS capacitor element M2 having opposite polarity is connected in parallel. A reference voltage Vref having a constant voltage value is supplied via a resistor R4 to a connection point between the gate of the first MOS capacitor element M1, the second capacitor C5, and the back gate of the second MOS capacitor element M2. The first control voltage VL is supplied to the connection point between the back gate of the first MOS capacitor element M1 and the first capacitor C4 via the resistor R5, and the connection point between the second capacitor C5 and the gate of the third MOS capacitor element M3. In addition, the first control voltage VL is supplied through the resistor R9. Further, the temperature compensation circuit is configured to supply the second control voltage VH to the connection point between the first capacitor C4, the back gate of the third MOS capacitor element M3, and the gate of the second MOS capacitor element M2 via the resistor R7. is there.
The third frequency temperature compensation circuit Comp3 shown in FIG. 7 is configured by connecting in parallel a third MOS capacitor element M3 having a second capacitor C5 connected in series to a parallel connection circuit of the first and second MOS capacitor elements M1 and M2. It is a frequency temperature compensation circuit. The circuit including the first and second MOS capacitance elements M1 and M2 has the same circuit configuration as that of FIG. The first control voltage VL is applied to the gate of the third MOS capacitor element M3, the second control voltage VH is applied to the back gate, and the relationship between the temperature T and the capacitance C is the temperature T-capacitance C characteristic of FIG. It will be the same.

FIG. 8 is a circuit diagram showing the configuration of the temperature compensated piezoelectric oscillator of the fourth embodiment, in which an oscillation circuit OSC, a piezoelectric vibrator Xtal, a fourth frequency temperature compensation circuit Comp4, and a capacitor C3 are connected in series. The fourth frequency temperature compensation circuit Comp4 is a circuit in which a third capacitor C9 is connected in series to the third MOS capacitor element M3 of the frequency temperature compensation circuit Comp3 shown in FIG. .
That is, the fourth frequency temperature compensation circuit Comp4 includes a series connection circuit of the first MOS capacitor element M1 and the first capacitor C4, and a series connection circuit of the second capacitor C8, the third MOS capacitor element M3, and the third capacitor C9. The first MOS capacitor element and the second MOS capacitor element M2 having the opposite polarity are connected in parallel. Then, a reference voltage Vref having a constant voltage value is supplied via a resistor R4 to a connection point between the gate of the first MOS capacitor element M1, the second capacitor C8, and the back gate of the second MOS capacitor element M2. Further, the first control voltage VL is supplied to the connection point between the back gate of the first MOS capacitor element M1 and the first capacitor C4 via the resistor R5, and the second capacitor C8 and the gate of the third MOS capacitor element M3 are connected to each other. The first control voltage VL is supplied to the connection point via the resistor R9. Further, the second control voltage VH is supplied to the connection point between the back gate of the third MOS capacitor element M3 and the third capacitor C9 via the resistor R13, and the first capacitor C4, the third capacitor C9, and the second MOS capacitor element M2 are supplied. This is a temperature compensation circuit configured to supply the second control line pressure VH to the connection point with the gate via the resistor R7.

FIG. 9 is a circuit diagram showing the configuration of the temperature compensated piezoelectric oscillator of the fifth embodiment, and includes an oscillation circuit OSC, a piezoelectric vibrator Xtal, a fifth frequency temperature compensation circuit Comp5, and a capacitor C3. This is a temperature compensated oscillator configured in series connection. The fifth frequency temperature compensation circuit Comp5 includes a circuit in which a first MOS capacitor element M1, a first capacitor C6, a third MOS capacitor element M3, and a second capacitor C7 are connected in series, and a first MOS capacitor element having a polarity opposite to that of the first MOS capacitor element. This is a circuit configuration in which a 2MOS capacitor element M2 is connected in parallel. Then, a reference voltage Vref having a constant voltage value is supplied to the connection point between the gate of the first MOS capacitor element M1 and the back gate of the second MOS capacitor element M2 via the resistor R4. Further, the first control voltage VL is supplied to the connection point between the back gate of the first MOS capacitor element M1 and the first capacitor C6 via the resistor R5, and the connection between the first capacitor C6 and the gate of the third capacitor element M3. The first control voltage VL is supplied to the point through the first amplifier A1 and the resistor R10 which can adjust the gain. The second control voltage VH is supplied to the connection point between the back gate of the third MOS capacitor element M3 and the second capacitor C7 through the second amplifier A2 and the resistor R11, which can also be gain-adjusted, and the second capacitor C7 and the second capacitor C7. This is a temperature compensation circuit configured to supply the second control voltage VH to the connection point with the gate of the 2MOS capacitive element M2 via the resistor R12.
The fifth frequency temperature compensation circuit Comp5 is characterized in that the first and second amplifiers A1 and A2 are respectively connected to the gate and back gate of the third capacitor element M3 that compensates for the frequency temperature characteristics near room temperature. 2 Since the control voltages VL and VH are supplied, the voltage difference Vd between the back gate and the gate can be finely adjusted, and there is an effect that the accuracy of frequency temperature characteristic compensation is improved.

FIG. 10 is a circuit diagram showing a configuration of the temperature compensated piezoelectric oscillator of the sixth embodiment, in which an oscillation circuit OSC, a piezoelectric vibrator Xtal, a sixth frequency temperature compensation circuit Comp6, and a capacitor C3 are connected in series. It is a temperature compensated oscillator configured by connecting. The sixth frequency temperature compensation circuit Comp6 includes a series connection circuit of the first MOS capacitor element M1 and the first capacitor C4, a series connection circuit of the second capacitor C8, the third MOS capacitor element M3, and the third capacitor C9, This is a circuit in which a 1MOS capacitor element M1 and a second MOS capacitor element M2 having a reversed polarity are connected in parallel. Then, a reference voltage Vref having a constant voltage value is supplied via a resistor R4 to a connection point between the gate of the first MOS capacitor element M1, the second capacitor C8, and the back gate of the second MOS capacitor element M2. The first control voltage VL is supplied to the connection point between the back gate of the first MOS capacitor element M1 and the first capacitor C4 via the resistor R5, and the connection point between the second capacitor C8 and the gate of the third MOS capacitor element M3. In addition, the first control voltage VL is supplied through the first amplifier A1 and the resistor R10 which can adjust the gain. Further, the second control voltage VH is supplied to the connection point between the back gate of the third MOS capacitor element M3 and the third capacitor C9 via the second amplifier A2 and the resistor R11 that can be adjusted in gain, and the first capacitor C4 This is a temperature compensation circuit configured to supply the second control voltage VH via a resistor R7 to the connection point between the third capacitor C9 and the gate of the second MOS capacitor element M2.
The frequency temperature compensation circuit Comp6 of the sixth embodiment is substantially the same as the frequency temperature compensation circuit Comp5 of the fifth embodiment, but the first and second amplifiers are connected to both ends of the third MOS capacitor M3 via the first and second amplifiers. The difference is that the first and second control voltages VL and VH are applied. By adjusting the gains of the first and second amplifiers, the voltage difference Vd between the back gate and the gate of the third MOS capacitor element M3 can be finely adjusted, and the accuracy of compensation of the frequency temperature characteristics in the vicinity of room temperature is improved. There is an effect.

FIG. 11 is a circuit diagram showing the configuration of the temperature compensated piezoelectric oscillator of the seventh embodiment, and includes an oscillation circuit OSC, a piezoelectric vibrator Xtal, a seventh frequency temperature compensation circuit Comp7, and a capacitor C3. This is a temperature compensated oscillator configured in series connection. The seventh frequency temperature compensation circuit Comp7 includes a circuit in which a first MOS capacitor element M1 and a first capacitor C4 are connected in series to a circuit in which a second MOS capacitor element M2 having a polarity opposite to that of the first MOS capacitor element is connected in parallel. A circuit in which a two-capacitance C10 and a third MOS capacitive element M3 having the same polarity as the second MOS capacitive element M2 are connected in series and connected in series. Then, a reference voltage Vref having a constant voltage value is supplied to the connection point between the gate of the first MOS capacitor element M1 and the back gate of the second MOS capacitor element M2 via the resistor R4. Furthermore, the first control voltage VL is supplied to the connection point between the back gate of the first MOS capacitor element M1 and the first capacitor C4 via the resistor R5, and the first capacitor C4 and the gates of the second MOS capacitor element M2 The second control voltage VH is supplied to the connection point with the two capacitors C10 via the resistor R7. The second control voltage VH is supplied to the connection point between the back gate of the second capacitor C10 and the third MOS capacitor element M3 via the second amplifier A2 and the resistor R11 capable of gain adjustment, and the gate of the third MOS capacitor element M3 is supplied. The temperature compensation circuit is configured to supply the first control voltage VL via the first amplifier A1 and the resistor R10 that can adjust the gain.
The frequency temperature compensation circuit Comp7 of the seventh embodiment is basically the same as the frequency temperature compensation circuit Comp2 shown in FIG. 6, but a second capacitor C10 is connected in series to the back gate of the third MOS capacitor element M3. The difference is that the first and second control voltages VL and VH are applied to the gate and back gate of the third MOS capacitor element M3 via the first and second amplifiers A1 and A2, respectively. Therefore, there is an advantage that the compensation accuracy is improved because the frequency temperature compensation near room temperature can be finely performed.

The above is the case where the frequency-temperature characteristic (df / f-Temp) of the crystal resonator has a maximum value and a minimum value with an inflection point with respect to the temperature change as shown in FIG. The frequency compensation method has been described. As shown in FIG. 22C, the frequency compensation method in the case where the frequency temperature characteristic has a rising characteristic with respect to an increase in temperature will be described below.
FIG. 12 is a circuit diagram showing the configuration of the temperature compensated piezoelectric oscillator of the eighth embodiment according to the present invention. The temperature compensated piezoelectric oscillator is a temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit OSC, a piezoelectric vibrator Xtal, an eighth frequency temperature compensation circuit Comp′1, and a capacitor C3 in series. The difference from the temperature compensated piezoelectric oscillator of the first embodiment shown in FIG. 1 is that the polarity of the third MOS capacitor element M3 is reversed. A temperature T-capacitance C characteristic when the first and second control voltages VL and VH are applied to both ends of the third MOS capacitor element M3 shown in FIG. 12 is a characteristic obtained by turning the curve shown in FIG. That is, as shown in FIG. 13A, the capacity increases with increasing temperature. When this is converted into a frequency-temperature characteristic (temperature T−frequency df / f) as shown in FIG. 5, it becomes a characteristic of decreasing to the right as the temperature T increases as shown in FIG. As already described, the third MOS capacitor element M3 is involved in compensation of the intermediate temperature part centered on the normal temperature, and the first MOS capacitor element M1 and the second MOS capacitor element M2 are responsible for compensation of the low temperature part and the high temperature part, respectively. The operation of the first MOS capacitor element M1 and the second MOS capacitor element M2 is as described in FIG. Therefore, by using the frequency temperature compensation circuit Comp′1 shown in FIG. 12, it is possible to compensate the crystal oscillator that rises to the right as shown in FIG. 22C.

FIG. 14 is a circuit diagram showing the configuration of the temperature compensated piezoelectric oscillator of the ninth embodiment according to the present invention. The difference from the temperature compensated piezoelectric oscillator of the second embodiment shown in FIG. 6 is that the polarity of the third MOS capacitor element M3 is reversed. By using the frequency temperature compensation circuit Comp′2 shown in FIG. 14, it is possible to compensate for the crystal oscillator that rises to the right as shown in FIG. 22C.
Similarly, FIGS. 15 to 19 are circuit diagrams showing configurations of the temperature compensated piezoelectric oscillators of the tenth to fourteenth embodiments, respectively. The frequency temperature compensation circuits Comp′3 to Comp′7 of the temperature compensated piezoelectric oscillator shown in FIGS. 15 to 19 are different from the frequency temperature compensation circuits Comp3 to Comp7 shown in FIGS. 7 to 11, respectively, in the third MOS capacitor element M3. The polarity is reversed. By reversing the polarity of the third MOS capacitor element M3, it is possible to compensate for the crystal oscillator that rises to the right as the temperature increases as shown in FIG.

FIG. 20 is a circuit diagram showing a configuration of a temperature compensated piezoelectric oscillator according to a fifteenth embodiment of the present invention. The difference from the temperature compensated piezoelectric oscillator of the fourteenth embodiment shown in FIG. 19 is that the first and second control voltages VL and VH are connected to the first and second amplifier circuits A1 and A2 at the first and second contact points, respectively. The second switches SW1 and SW2 are inserted, and the first and second reference voltages Vref1 and Vref2 are connected to the first and second switches SW1 and SW2, respectively. The operation of the first and second switches SW1 and SW2 will be described. When the first and second switches SW1 and SW2 are connected to the first and second control voltages VL and VH, respectively, the fourteenth embodiment. It operates in the same manner as the temperature compensated piezoelectric oscillator. When the first and second switches SW1 and SW2 are connected to the first and second reference voltages Vref1 and Vref2, respectively, the third MOS capacitor element M3 functions as a fixed capacitor. In other words, the temperature compensation function of the middle temperature portion centered on the normal temperature that the third MOS capacitor element M3 has played is lost, and the frequency of the crystal resonator having flat characteristics near the normal temperature as shown in FIG. Will compensate.
Further, by adjusting the gains of the first and second amplifier circuits A1 and A2, even if the slope of the right shoulder in FIG. 22C is steep or the slope is gentle, It becomes possible to compensate the frequency of the crystal resonator according to the degree of inclination.

In FIG. 20, if the polarity of the third MOS capacitor element M3 is reversed and the gains of the first and second amplifier circuits A1 and A2 are adjusted, the degree of inclination near room temperature in FIG. Needless to say, the frequency of the crystal unit can be compensated.
When the temperature compensated piezoelectric oscillator as shown in FIG. 20 is made into an IC excluding the crystal oscillator, the frequency temperature characteristics of the crystal oscillator are shown in FIGS. 22A, 22B, and 22C with one IC. Frequency compensation is possible for any crystal oscillator that has flat characteristics near room temperature, characteristics that have a maximum value and minimum value across an inflection point, and characteristics that rise to the right There is an effect of becoming.

1 is a circuit diagram showing a configuration of a temperature compensated piezoelectric oscillator according to a first embodiment of the present invention. The figure which shows the voltage difference Vd-capacitance C characteristic of a MOS capacitive element. The figure which shows the relationship between temperature T, the reference voltage Vref, and 1st and 2nd control voltage VL, VH. (A)-(c) is a figure which shows the relationship between the temperature T and the capacity | capacitance C which 1st, 2nd and 3rd MOS capacitive element M1, M2, and M3 exhibit, respectively. (A)-(c) is a figure which shows the frequency temperature characteristic by each of 1st, 2nd and 3rd MOS capacitive element M1, M2, M3, (d) is a figure which shows the frequency temperature characteristic of the frequency temperature compensation circuit Comp1. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 2nd Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 3rd Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 4th Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 5th Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 6th Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 7th Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of an 8th Example. (A) of 3rd MOS capacitive element M3 is a figure which shows temperature T-capacitance C characteristic, (b) is a figure which shows temperature T-frequency deviation df / f characteristic. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 9th Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 10th Example. A circuit diagram showing composition of a temperature compensation piezoelectric oscillator of an 11th example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 12th Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of a 13th Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of 14th Example. The circuit diagram which shows the structure of the temperature compensation piezoelectric oscillator of 15th Example. The circuit diagram which shows the structure of the conventional temperature compensation piezoelectric oscillator. (A) of the AT-cut quartz resonator, (a) shows a frequency temperature characteristic that is flat near room temperature, (b) shows a frequency temperature characteristic having a maximum value and a minimum value across an inflection point, (c) ) Is a graph showing the frequency-temperature characteristics rising to the right.

  M1, M2, M3 ... MOS capacitance elements, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13 ... resistors, C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 ... capacitance, Tr1 ... transistor, Xtal ... piezoelectric vibrator, Vref ... reference voltage, Vref1 ... first reference voltage, Vref2 ... second reference voltage, VL ... first control voltage, VH ... second Control voltage, Vcc ... Power supply voltage, A1, A2 ... Amplifier

Claims (9)

A temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series,
The frequency temperature compensation circuit includes first, second, and third MOS capacitance elements, and is a circuit in which the second MOS capacitance element is connected in parallel to a circuit in which the first MOS capacitance element and the third MOS capacitance element are connected in series. ,
Supplying a reference voltage having a constant voltage value to a connection point between one terminal of the first MOS capacitor element and one terminal of the second MOS capacitor element;
Supplying a first control voltage to a connection point between the other terminal of the first MOS capacitor element and one terminal of the third MOS capacitor element;
A temperature compensated piezoelectric oscillator configured to supply a second control voltage to a connection point between the other terminal of the third MOS capacitor and the other terminal of the second MOS capacitor. A temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series,
The frequency temperature compensation circuit includes first, second, and third MOS capacitor elements and a first capacitor, and the second MOS capacitor element is connected in parallel to a circuit in which the first MOS capacitor element and the first capacitor are connected in series. And a circuit in which the third MOS capacitor element is connected in series,
Supplying a reference voltage having a constant voltage value to a connection point between one terminal of the first MOS capacitor element and one terminal of the second MOS capacitor element;
Supplying a first control voltage to a connection point between the other terminal of the first MOS capacitor element and one terminal of the first capacitor and to one terminal of the third MOS capacitor element;
The second control voltage is supplied to a connection point between the other terminal of the third MOS capacitor element, the other terminal of the first capacitor, and the other terminal of the second MOS capacitor element. Temperature compensated piezoelectric oscillator. A temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series,
The frequency temperature compensation circuit includes first, second, and third MOS capacitance elements, and first and second capacitance elements, and a circuit in which the first MOS capacitance element and the first capacitance are connected in series, A circuit in which two capacitors and a third MOS capacitor element are connected in series, and a circuit in which the second MOS capacitor element is connected in parallel.
Supplying a reference voltage having a constant voltage value to a connection point between one terminal of the first MOS capacitor element, one terminal of the second capacitor, and one terminal of the second MOS capacitor element;
A connection point between the other terminal of the first MOS capacitor element and one terminal of the first capacitor, and a connection point between the other terminal of the second capacitor and one terminal of the third MOS capacitor element are respectively first. Supply control voltage,
The second control voltage is supplied to a connection point between the other terminal of the first capacitor, the other terminal of the third MOS capacitor, and the other terminal of the second MOS capacitor. Temperature compensated piezoelectric oscillator. A temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series,
The frequency temperature compensation circuit includes first, second, and third MOS capacitor elements, and first, second, and third capacitors, and a series connection circuit of the first MOS capacitor element and the first capacitor, A series connection circuit of a second capacitor, the third MOS capacitor and the third capacitor, and a circuit in which the second MOS capacitor is connected in parallel;
Supplying a reference voltage having a constant voltage value to a connection point between one terminal of the first MOS capacitor element, one terminal of the second capacitor, and one terminal of the second MOS capacitor element;
The first control is performed at a connection point between the other terminal of the first MOS capacitor element and one terminal of the first capacitor, and a connection point between the other terminal of the second capacitor and one terminal of the third MOS capacitor element. Supply voltage,
A connection point between the other terminal of the third MOS capacitor element and one terminal of the third capacitor, the other terminal of the first capacitor, the other terminal of the third capacitor, and the other of the second MOS capacitor element. A temperature-compensated piezoelectric oscillator configured to supply a second control voltage to a connection point with the terminal. A temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series,
The frequency temperature compensation circuit includes first, second, and third MOS capacitors, first and second capacitors, and first and second amplifiers that can adjust gain, and the first MOS capacitors, the first MOS capacitors, 1 capacitor, a circuit in which the third MOS capacitor element and the second capacitor are connected in series, and a circuit in which the second MOS capacitor element is connected in parallel,
Supplying a reference voltage having a constant voltage value to a connection point between one terminal of the first MOS capacitor element and one terminal of the second MOS capacitor element;
Supplying a first control voltage to a connection point between the other terminal of the first MOS capacitor and the one terminal of the first capacitor;
Supplying a first control voltage via a first amplifier to a connection point between the other terminal of the first capacitor and one terminal of the third MOS capacitor;
Supplying a second control voltage to a connection point between the other terminal of the third MOS capacitor element and one terminal of the second capacitor via a second amplifier;
A temperature compensated piezoelectric oscillator configured to supply a second control voltage to a connection point between the other terminal of the second capacitor and the other terminal of the second MOS capacitor. A temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series,
The frequency temperature compensation circuit includes first, second, and third MOS capacitors, first, second, and third capacitors, and first and second amplifiers that can be adjusted in gain.
The frequency temperature compensation circuit includes a series connection circuit of the first MOS capacitor element and the first capacitor, a series connection circuit of the second capacitor, the third MOS capacitor element, and the third capacitor, and the second MOS capacitor element. Are connected in parallel,
Supplying a reference voltage having a constant voltage value to a connection point between one terminal of the first MOS capacitor element, one terminal of the second capacitor, and one terminal of the second MOS capacitor element;
Supplying a first control voltage to a connection point between the other terminal of the first MOS capacitor and the one terminal of the first capacitor;
Supplying a first control voltage via a first amplifier to a connection point between the other terminal of the second capacitor and one terminal of the third MOS capacitor;
Supplying a second control voltage via a second amplifier to a connection point between the other terminal of the third MOS capacitor element and one terminal of the third capacitor;
The second control voltage is supplied to a connection point between the other terminal of the first capacitor, the other terminal of the third capacitor, and the other terminal of the second MOS capacitor element. Temperature compensated piezoelectric oscillator. A temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series,
The frequency temperature compensation circuit includes first, second, and third MOS capacitors, first and second capacitors, and first and second amplifiers that can adjust gain,
The frequency temperature compensation circuit includes a circuit in which the second MOS capacitor element is connected in parallel to a circuit in which the first MOS capacitor element and the first capacitor are connected in series, and the second capacitor and the third MOS capacitor element are connected in series. Circuit that is connected in series,
Supplying a reference voltage having a constant voltage value to a connection point between one terminal of the first MOS capacitor element and one terminal of the second MOS capacitor element;
Supplying a first control voltage to a connection point between the other terminal of the first MOS capacitor and the one terminal of the first capacitor;
Supplying a second control voltage to a connection point between the other terminal of the first capacitor, one terminal of the second capacitor, and the other terminal of the second MOS capacitor;
Supplying a second control voltage via a second amplifier to a connection point between the other terminal of the second capacitor and one terminal of the third MOS capacitor;
A temperature compensated piezoelectric oscillator configured to supply a first control voltage to the other terminal of the third MOS capacitor element via a first amplifier. A temperature compensated piezoelectric oscillator configured by connecting an oscillation circuit, a piezoelectric vibrator, and a frequency temperature compensation circuit in series,
The frequency temperature compensation circuit includes first, second, and third MOS capacitors, first and second capacitors, gain-adjustable first and second amplifiers, first and second switches, first, A second reference voltage,
The frequency temperature compensation circuit includes a circuit in which the second MOS capacitor element is connected in parallel to a circuit in which the first MOS capacitor element and the first capacitor are connected in series, and the second capacitor and the third MOS capacitor element are connected in series. Circuit that is connected in series,
Supplying a reference voltage having a constant voltage value to a connection point between one terminal of the first MOS capacitor element and one terminal of the second MOS capacitor element;
Supplying a first control voltage to a connection point between the other terminal of the first MOS capacitor and the one terminal of the first capacitor;
Supplying a second control voltage to a connection point between the other terminal of the first capacitor, one terminal of the second capacitor, and the other terminal of the second MOS capacitor;
An output of a second amplifier is connected to a connection point between the other terminal of the second capacitor and one terminal of the third MOS capacitor element, and either one of the second control voltage and the second reference voltage is set. Selected by the second switch and supplied to the input of the second amplifier;
The output of the first amplifier is connected to the other terminal of the third MOS capacitor element, and one of the first control voltage and the first reference voltage is selected by the first switch. A temperature compensated piezoelectric oscillator characterized by being supplied to an input of an amplifier.   The piezoelectric resonator is a crystal resonator, and the frequency-temperature characteristic of the crystal resonator is a flat characteristic near normal temperature, a characteristic having a maximum value and a minimum value across an inflection point, or a right against an increase in temperature. The temperature-compensated piezoelectric oscillator according to any one of claims 1 to 8, wherein the temperature-compensated piezoelectric oscillator corresponds to any of the rising characteristics.

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