Circuit devices and oscillators

Abstract

To provide a circuit device and the like capable of realizing various operation modes with variable capacitance circuits having different polarities of voltage capacitance characteristics.SOLUTION: A circuit device 20 includes an oscillation circuit 30 that includes a first variable capacitance circuit 31 with a capacitance having positive change characteristics to a capacitance control voltage and a second variable capacitance circuit 32 with a capacitance having negative change characteristics to the capacitance control voltage, and that oscillates a vibrator 10. The circuit device 20 includes a switch circuit 36 in which a first input voltage VI1 is input to a first input terminal TI1, a second input voltage VI2 is input to a second input terminal TI2, a first output voltage VQ1 selected from among a plurality of voltages including the first input voltage VI1 and the second input voltage VI2 is output to a first output terminal TQ1 electrically connected with the first variable capacitance circuit 31, and a second output voltage VQ2 selected from among the plurality of voltages is output to a second output terminal TQ2 electrically connected with the second variable capacitance circuit 32.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a circuit device, an oscillator, and the like.

Background Art

[0002] In a circuit device that oscillates a vibrator such as a crystal oscillator, a variable capacitance circuit for adjusting the oscillation frequency is provided. For example, in the oscillation circuit of Patent Document 1, an inverting amplifier that inverts the polarity of a control voltage is provided between a voltage-controlled oscillator that changes the oscillation frequency according to the control voltage and an amplifier that outputs the control voltage.

Prior Art Documents

Patent Documents

[0003] ]>

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art of Patent Document 1, the operation by negative feedback control is enabled without changing the polarity of the control element inside the oscillator or separately creating a non-standard oscillator. However, there has been no proposal for a circuit device or an oscillator that can realize various operation modes by using variable capacitance circuits having different polarities of voltage-capacitance characteristics.

Means for Solving the Problems

[0005] One aspect of the present disclosure relates to a circuit device including an oscillator that causes an oscillator to oscillate, comprising a first variable capacitance circuit having a positive capacitance change characteristic with respect to a capacitance control voltage, and a second variable capacitance circuit having a negative capacitance change characteristic with respect to the capacitance control voltage, and a switch circuit that receives a first input voltage at a first input terminal, receives a second input voltage at a second input terminal, outputs a first output voltage selected from a plurality of voltages including the first input voltage and the second input voltage to a first output terminal to which the first variable capacitance circuit is electrically connected, and outputs a second output voltage selected from the plurality of voltages to a second output terminal to which the second variable capacitance circuit is electrically connected.

[0006] Another aspect of this disclosure relates to a circuit device that includes a first variable capacitance circuit in which the capacitance change characteristic with respect to a capacitance control voltage is positive, and a second variable capacitance circuit in which the capacitance change characteristic with respect to the capacitance control voltage is negative, an oscillator circuit that causes an oscillator to oscillate, and a frequency control circuit that outputs a frequency control voltage of the oscillation frequency of the oscillator circuit, wherein in the first mode, the frequency control voltage is input to the second variable capacitance circuit as the capacitance control voltage, and in the second mode, the frequency control voltage is input to the first variable capacitance circuit as the capacitance control voltage.

[0007] Another aspect of the present disclosure relates to an oscillator including an oscillator and a circuit device, the circuit device including a first variable capacitance circuit having a positive capacitance change characteristic with respect to a capacitance control voltage and a second variable capacitance circuit having a negative capacitance change characteristic with respect to the capacitance control voltage, which causes the oscillator to oscillate; and a switch circuit to which a first input voltage is input to a first input terminal and a second input voltage is input to a second input terminal, which outputs a first output voltage selected from a plurality of voltages including the first input voltage and the second input voltage to a first output terminal to which the first variable capacitance circuit is connected, and which outputs a second output voltage selected from the plurality of voltages to a second output terminal to which the second variable capacitance circuit is connected.

[0008] Another aspect of the present disclosure relates to an oscillator comprising an oscillator and a circuit device, the circuit device comprising a first variable capacitance circuit having a positive capacitance change characteristic with respect to a capacitance control voltage and a second variable capacitance circuit having a negative capacitance change characteristic with respect to the capacitance control voltage, an oscillator circuit for causing the oscillator to oscillate and a frequency control circuit for outputting a frequency control voltage of the oscillation frequency of the oscillator circuit, wherein in a first mode, the frequency control voltage is input to the second variable capacitance circuit as the capacitance control voltage, and in a second mode, the frequency control voltage is input to the first variable capacitance circuit as the capacitance control voltage. [Brief explanation of the drawing]

[0009] [Figure 1] An example of the configuration of the circuit device and oscillator according to this embodiment. [Figure 2] Detailed configuration example of the circuit device and oscillator of this embodiment. [Figure 3] Diagram illustrating the voltage capacitance characteristics of the positive characteristic of the first variable capacitance circuit. [Figure 4] Diagram illustrating the negative voltage capacitance characteristics of the second variable capacitance circuit. [Figure 5] An example of a switch circuit configuration. [Figure 6] A diagram illustrating the setting of the operating mode using a switch circuit. [Figure 7] Other examples of switch circuit configurations. [Figure 8] Detailed other configuration examples of the circuit device and oscillator of this embodiment. [Figure 9] A first example of an oscillator circuit configuration. [Figure 10] A second example of the oscillator circuit configuration. [Figure 11] Diagram illustrating the first variable capacitance circuit. [Figure 12] Diagram illustrating the voltage-capacitance characteristics of the first variable capacitance circuit. [Figure 13] Diagram illustrating the voltage-capacitance characteristics of the first variable capacitance circuit. [Figure 14] Diagram illustrating the second variable capacitance circuit. [Figure 15] Diagram illustrating the voltage-capacitance characteristics of the second variable capacitance circuit. [Figure 16] Explanatory diagram of the voltage-capacitance characteristics of the second variable capacitance circuit. [Figure 17] Example of the frequency-temperature characteristics of the oscillator. [Figure 18] Example of the temperature characteristics of the temperature compensation voltage when using a second variable capacitance circuit with negative characteristics. [Figure 19] Example of the temperature characteristics of the temperature compensation voltage when using a first variable capacitance circuit with positive characteristics. [Figure 20] Example of the configuration of the temperature compensation circuit. [Figure 21] Example of the configuration of an amplifier circuit with class A operation. [Figure 22] Example of the configuration of an amplifier circuit with class AB operation. [Figure 23] Example of the configuration of the frequency control circuit. [Figure 24] First structural example of the oscillator. [Figure 25] Second structural example of the oscillator.

Mode for Carrying Out the Invention

[0010] Hereinafter, this embodiment will be described. Note that the embodiment described below does not unduly limit the content described in the claims. Also, not all of the configurations described in this embodiment are essential constituent elements.

[0011] 1. Circuit device Fig. 1 shows a configuration example of the circuit device 20 of this embodiment. The circuit device 20 of this embodiment includes an oscillation circuit 30 and a switch circuit 36. Also, the oscillator 4 of this embodiment includes an oscillator 10 and a circuit device 20. The oscillator 10 is electrically connected to the circuit device 20.

[0012] The oscillator 10 is an element that generates mechanical vibrations in response to an electrical signal. The oscillator 10 can be realized by a vibrating element such as a quartz crystal. For example, the oscillator 10 can be realized by a quartz crystal that vibrates with a thickness shear, such as an AT cut or SC cut, a tuning fork type quartz crystal, or a double tuning fork type quartz crystal. For example, the oscillator 10 may be an oscillator built into a temperature-compensated crystal oscillator (TCXO) without a constant temperature chamber, or an oscillator built into a constant temperature chamber type quartz oscillator (OCXO) with a constant temperature chamber. Alternatively, the oscillator 10 may be an oscillator built into an SPXO (Simple Packaged Crystal Oscillator). The oscillator 10 of this embodiment can also be realized by various vibrating elements such as vibrating elements other than thickness shear, tuning fork, or double tuning fork types, or piezoelectric vibrating elements made of materials other than quartz. For example, the oscillator 10 can be a SAW (Surface Acoustic Wave) resonator or a MEMS (Micro Electro Mechanical Systems) oscillator, which is a silicon oscillator formed using a silicon substrate.

[0013] The circuit device 20 is an integrated circuit (IC). For example, the circuit device 20 is an IC manufactured by a semiconductor process, and is a semiconductor chip in which circuit elements are formed on a semiconductor substrate. In Figure 1, the circuit device 20 includes an oscillator circuit 30 and a switch circuit 366, and the oscillator circuit 30 includes a first variable capacitance circuit 31 and a second variable capacitance circuit 32.

[0014] The oscillation circuit 30 is a circuit that causes the resonator 10 to oscillate. For example, the oscillation circuit 30 generates an oscillation signal by causing the resonator 10 to oscillate. The oscillation signal is an oscillation clock signal. For example, the oscillation circuit 30 can be realized by an oscillation drive circuit electrically connected to one end and the other end of the resonator 10, and passive elements such as capacitors and resistors. The drive circuit can be realized by, for example, a CMOS inverter circuit or a bipolar transistor. The drive circuit is the core circuit of the oscillation circuit 30, and the drive circuit causes the resonator 10 to oscillate by voltage driving or current driving the resonator 10. Various types of oscillation circuits such as inverter type, Pierce type, Colpitts type, or Hartley type can be used as the oscillation circuit 30. Note that the connection in this embodiment is an electrical connection. An electrical connection is a connection that allows electrical signals to be transmitted, and is a connection that enables the transmission of information by electrical signals. The electrical connection may be a connection via passive elements, etc.

[0015] The oscillation circuit 30 also includes a first variable capacitance circuit 31 and a second variable capacitance circuit 32. The first variable capacitance circuit 31 and the second variable capacitance circuit 32 are circuits that change the capacitance at least one of the two ends of the oscillator 10, and the oscillation frequency of the oscillation circuit 30 can be adjusted by adjusting the capacitance of the first variable capacitance circuit 31 and the second variable capacitance circuit 32. The first variable capacitance circuit 31 and the second variable capacitance circuit 32 can be realized by variable capacitance elements such as varactors. For example, each of the first variable capacitance circuit 31 and the second variable capacitance circuit 32 is composed of at least one variable capacitance element.

[0016] The switch circuit 36 ​​is a circuit that supplies capacitance control voltages to the first variable capacitance circuit 31 and the second variable capacitance circuit 32 of the oscillator circuit 30. The switch circuit 36 ​​receives the first input voltage VI1 and the second input voltage VI2 as inputs and outputs the first output voltage VQ1 and the second output voltage VQ2. The first output voltage VQ1 and the second output voltage VQ2 are supplied to the first variable capacitance circuit 31 and the second variable capacitance circuit 32 as capacitance control voltages. The switch circuit 36 ​​is composed of, for example, multiple switch elements. Also in Figure 1, a fixed voltage, such as a reference voltage VREF and a ground voltage GND, is supplied to the switch circuit 36.

[0017] In this embodiment, the oscillation circuit 30 includes a first variable capacitance circuit 31 whose capacitance change characteristic with respect to the capacitance control voltage is positive, and a second variable capacitance circuit 32 whose capacitance change characteristic with respect to the capacitance control voltage is negative. For example, the first variable capacitance circuit 31 and the second variable capacitance circuit 32 have different polarities in the capacitance change characteristic with respect to the capacitance control voltage. A positive capacitance change characteristic means, for example, as explained in Figure 3 below, that the capacitance increases as the capacitance control voltage increases. A negative capacitance change characteristic means, for example, as explained in Figure 4 below, that the capacitance decreases as the capacitance control voltage increases. Capacitance can also be called capacitance value.

[0018] The switch circuit 36 ​​receives a first input voltage VI1 at the first input terminal TI1 and a second input voltage VI2 at the second input terminal TI2. These first input voltages VI1 and VI2 are, for example, voltages input from a predetermined circuit of the circuit device 20. Alternatively, the first input voltages VI1 and VI2 may be voltages input from outside the circuit device 20. The switch circuit 36 ​​also outputs a first output voltage VQ1, selected from a plurality of voltages including the first input voltage VI1 and the second input voltage VI2, to the first output terminal TQ1 to which the first variable capacitor circuit 31 is electrically connected. The switch circuit 36 ​​also outputs a second output voltage VQ2, selected from a plurality of voltages including the first input voltage VI1 and the second input voltage VI2, to the second output terminal TQ2 to which the second variable capacitor circuit 32 is electrically connected.

[0019] For example, the switch circuit 36 ​​outputs a voltage selected from the first input voltage VI1 and the second input voltage VI2 as the first output voltage VQ1 and the second output voltage VQ2. In this case, the multiple voltages to be selected are the first input voltage VI1 and the second input voltage VI2. Alternatively, the switch circuit 36 ​​may output a voltage selected from the first input voltage VI1, the second input voltage VI2, and one or more fixed voltages as the first output voltage VQ1 and the second output voltage VQ2. In this case, the multiple voltages to be selected are the first input voltage VI1, the second input voltage VI2, and a fixed voltage. The fixed voltage is a voltage with a constant value, such as a reference voltage VREF or a ground voltage GND. The switch circuit 36 ​​also includes multiple switch elements for selecting a voltage from a plurality of voltages, including the first input voltage VI1 and the second input voltage VI2, and outputting it as the first output voltage VQ1 and the second output voltage VQ2. In this case, the on / off control of each of the multiple switch elements is performed based on a switch control signal from a control circuit (not shown).

[0020] In this way, a voltage selected from among multiple voltages, including the first input voltage VI1 and the second input voltage VI2, can be output as the first output voltage VQ1 and the second output voltage VQ2 to the first variable capacitance circuit 31 and the second variable capacitance circuit 32, respectively. The first output voltage VQ1 can then be input as a capacitance control voltage to the first variable capacitance circuit 31, which has a positive voltage-capacitance characteristic, to adjust or set the oscillation frequency of the oscillation circuit 30. Alternatively, the second output voltage VQ2 can be input as a capacitance control voltage to the second variable capacitance circuit 32, which has a negative voltage-capacitance characteristic, to adjust or set the oscillation frequency of the oscillation circuit 30. For example, it becomes possible to realize an operating mode in which the first input voltage VI1 is input as the first output voltage VQ1 to the first variable capacitance circuit 31 with a positive characteristic, and the second input voltage VI2 is input as the second output voltage VQ2 to the second variable capacitance circuit 32 with a negative characteristic. Alternatively, it becomes possible to realize an operating mode in which, for example, the first input voltage VI1 is input to the second variable capacitance circuit 32 with negative characteristics as the second output voltage VQ2, and the second input voltage VI2 is input to the first variable capacitance circuit 31 with positive characteristics as the first output voltage VQ1. Alternatively, it becomes possible to realize an operating mode in which, for example, a fixed voltage such as VREF or GND is input to the first variable capacitance circuit 31 with positive characteristics as the first output voltage VQ1, or an operating mode in which a fixed voltage such as VREF or GND is input to the second variable capacitance circuit 32 with negative characteristics as the second output voltage VQ2. Therefore, it becomes possible to provide a circuit device 20 and oscillator 4 that can realize various operating modes using the first variable capacitance circuit 31 and the second variable capacitance circuit 32 with different polarity voltage capacitance characteristics.

[0021] Figure 2 shows a detailed configuration example of the circuit device 20 and oscillator 4 of this embodiment. In Figure 2, the circuit device 20 includes an oscillation circuit 30, a switch circuit 36, a temperature compensation circuit 40, a temperature sensor 48, a frequency control circuit 50, a logic circuit 60, a non-volatile memory 70, an output circuit 80, and a power supply circuit 90. The oscillator 4 includes a vibrator 10 and the circuit device 20. The vibrator 10 is electrically connected to the circuit device 20. For example, the vibrator 10 and the circuit device 20 are electrically connected using internal wiring of the package housing the vibrator 10 and the circuit device 20, bonding wires, or metal bumps. Note that the circuit device 20 and oscillator 4 are not limited to the configuration in Figure 2, and various modifications can be made, such as omitting some of these components, adding other components, or replacing some components with other components.

[0022] The circuit device 20 also includes pads PVDD, PGND, PX1, PX2, PVC, and PCK. The pads are terminals of the circuit device 20, which is a semiconductor chip. For example, in the pad area, a metal layer is exposed from the passivation film, which is an insulating layer, and this exposed metal layer constitutes the pads, which are terminals of the circuit device 20. Pads PVDD and PGND are the power supply pad and the ground pad, respectively. The power supply voltage VDD from an external power supply device is supplied to pad PVDD. Pad PGND is the pad to which the ground voltage GND is supplied. GND can also be called VSS, and the ground voltage is, for example, the earth potential. In this embodiment, ground will be written as GND as appropriate. For example, VDD corresponds to the high-potential side power supply, and GND corresponds to the low-potential side power supply. Pads PX1 and PX2 are pads for connecting the oscillator 10. Pad PVC is the input pad for the control voltage VC, and pad PCK is the output pad for the clock signal CK. Pads PVDD, PGND, PVC, and PCK are electrically connected to terminals TVDD, TGND, TVC, and TCK, which are external terminals for external connection of oscillator 4, respectively. For example, each of these pads and terminals is electrically connected using the package's internal wiring, bonding wires, or metal bumps.

[0023] The oscillation circuit 30 is electrically connected to the vibrator 10 via pads PX1 and PX2. Pads PX1 and PX2 are pads for connecting to the vibrator. The drive circuit for oscillation of the oscillation circuit 30 is provided between pads PX1 and PX2. The oscillation circuit 30 includes a first variable capacitance circuit 31 and a second variable capacitance circuit 32. By electrically connecting the first variable capacitance circuit 31 and the second variable capacitance circuit 32 to at least one of pads PX1 and PX2, the load capacitance of the oscillation circuit 30 can be variably adjusted.

[0024] The temperature compensation circuit 40 is a circuit that performs temperature compensation for the oscillation frequency of the oscillation circuit 30. For example, the temperature compensation circuit 40 outputs a temperature compensation voltage VCP that compensates for the oscillation frequency of the oscillation circuit 30 based on the temperature detection result of the temperature sensor 48. The temperature detection result is a temperature detection signal, for example, a temperature detection voltage. Temperature compensation is a process that suppresses and compensates for fluctuations in the oscillation frequency due to temperature fluctuations, for example. That is, the temperature compensation circuit 40 performs temperature compensation for the oscillation frequency of the oscillation circuit 30 so that the oscillation frequency remains constant even when there are temperature fluctuations.

[0025] Specifically, the temperature compensation circuit 40 performs analog temperature compensation, for example, using polynomial approximation. For example, when the temperature compensation voltage VCP that compensates for the frequency-temperature characteristics of the oscillator 10 is approximated by a polynomial, the temperature compensation circuit 40 performs analog temperature compensation based on the coefficient information of the polynomial. Analog temperature compensation is temperature compensation realized by, for example, summing analog signals such as current signals and voltage signals. For example, when the temperature compensation voltage VCP is approximated by a higher-order polynomial, the zero-order coefficient, first-order coefficient, and higher-order coefficient of the polynomial are stored as zero-order correction data, first-order correction data, and higher-order correction data, respectively, in a storage unit realized by, for example, a non-volatile memory 70. The higher-order coefficient is, for example, a coefficient of a higher order than the first order, and the higher-order correction data is correction data corresponding to the higher-order coefficient. For example, when the temperature compensation voltage VCP is approximated by a cubic polynomial, the zeroth, first, second, and third coefficients of the polynomial are stored in the memory as zeroth correction data, first, second, and third correction data. The temperature compensation circuit 40 then performs temperature compensation based on the zeroth to third correction data. In this case, the second correction data and temperature compensation based on the second correction data may be omitted. Also, for example, when the temperature compensation voltage VCP is approximated by a quintic polynomial, the zeroth, first, second, third, fourth, and fifth coefficients of the polynomial are stored in the memory as zeroth correction data, first, second, third, fourth, and fifth correction data. The temperature compensation circuit 40 then performs temperature compensation based on the zeroth to fifth correction data. In this case, the second or fourth correction data and temperature compensation based on the second or fourth correction data may be omitted. Furthermore, the degree of the polynomial approximation is arbitrary; for example, a polynomial approximation of a degree greater than the 5th degree may be used. Also, the temperature sensor 48 may perform the 0th-order correction.

[0026] The temperature sensor 48 is a sensor that detects temperature. Specifically, the temperature sensor 48 outputs a temperature-dependent voltage that changes according to the ambient temperature as a temperature detection voltage. For example, the temperature sensor 48 generates a temperature detection voltage, which is a temperature detection signal, using a circuit element that has temperature dependence. Specifically, the temperature sensor 48 outputs a temperature detection voltage whose voltage changes depending on the temperature, for example, by using the temperature dependence of the forward voltage of a PN junction. In Figure 2, the temperature sensor 48 is provided in the circuit device 20, but it is also possible to implement a modified version in which the temperature sensor 48 is provided outside the circuit device 20, and the temperature compensation circuit 40 performs temperature compensation based on a temperature detection signal such as a temperature detection voltage input from the outside. It is also possible to implement a modified version using a digital temperature sensor circuit as the temperature sensor 48. In this case, it is sufficient to generate the temperature detection voltage by D / A conversion of the temperature detection data.

[0027] The frequency control circuit 50 is a circuit that controls the oscillation frequency of the oscillation circuit 30. Specifically, the frequency control circuit 50 outputs a frequency control voltage VFC of the oscillation frequency. For example, the frequency control circuit 50 generates and outputs the frequency control voltage VFC based on a control voltage input from an external source. Alternatively, the frequency control circuit 50 may generate the frequency control voltage VFC based on a control voltage obtained by D / A conversion of control data input from an external source. By providing such a frequency control circuit 50, it becomes possible to control the oscillation frequency of the oscillation circuit 30 to a desired frequency. For example, by providing a temperature compensation circuit 40 and a frequency control circuit 50, it becomes possible to set the oscillation frequency to a desired frequency according to an external control voltage or control data while performing temperature compensation for the oscillation frequency.

[0028] Specifically, the frequency control circuit 50 receives an external control voltage VC. For example, the control voltage VC from an external system, such as a microcomputer or various ICs, is input to the frequency control circuit 50 via terminal TVC and pad PVC. As an example, the oscillator circuit 30 of the circuit device 20 functions as a voltage-controlled oscillator, and a PLL feedback loop is formed by the external system. The frequency control circuit 50 then outputs a frequency control voltage VFC corresponding to the external control voltage VC. For example, the frequency control circuit 50 outputs a frequency control voltage VFC obtained by gain-adjusting the control voltage VC. Alternatively, digital control data may be input to the circuit device 20 via an interface circuit (not shown), and the control voltage VC obtained by D / A conversion of this control data may be input to the frequency control circuit 50.

[0029] The logic circuit 60 is a control circuit that performs various control processes. For example, the logic circuit 60 controls the entire circuit device 20 and controls the operation sequence of the circuit device 20. The logic circuit 60 also performs various processes for controlling the oscillator circuit 30, controls the temperature sensor 48, the output circuit 80, or the power supply circuit 90, or controls the reading and writing of information to the non-volatile memory 70. The logic circuit 60 can be realized by an ASIC (Application Specific Integrated Circuit) circuit with automatic placement and routing, such as a gate array.

[0030] The non-volatile memory 70 is a memory that retains information even without a power supply. For example, the non-volatile memory 70 is a memory that can retain information even without a power supply and can also rewrite information. The non-volatile memory 70 stores various information necessary for the operation of the circuit device 20. The non-volatile memory 70 can be implemented as an EEPROM (Electrically Erasable Programmable Read-Only Memory) realized by FAMOS memory (Floating gate Avalanche injection MOS memory) or MONOS memory (Metal-Oxide-Nitride-Oxide-Silicon memory). The non-volatile memory 70 stores correction data such as primary correction data and higher-order correction data used for temperature compensation of the temperature compensation circuit 40.

[0031] The output circuit 80 outputs a clock signal CK based on the oscillation signal of the oscillator circuit 30. For example, the output circuit 80 buffers the oscillation signal, which is the oscillation clock signal from the oscillator circuit 30, and outputs it as a clock signal CK to the pad PCK. This clock signal CK is then output externally via the clock output terminal TCK of the oscillator 4. For example, the output circuit 80 outputs the clock signal CK in single-ended CMOS signal format. Alternatively, the output circuit 80 may output the clock signal CK in a signal format other than CMOS. Furthermore, a clock signal generation circuit, such as a PLL circuit, may be provided after the oscillator circuit 30 to generate a clock signal CK with a frequency multiplied by the frequency of the oscillation signal, and the output circuit 80 may buffer and output the clock signal CK generated by this clock signal generation circuit.

[0032] The power supply circuit 90 receives the power supply voltage VDD from pad PVDD and the ground voltage GND from pad PGND, and supplies various power supply voltages for the internal circuits of the circuit device 20. For example, the power supply circuit 90 supplies a regulated power supply voltage, which is a regulated power supply voltage obtained by regulating the power supply voltage VDD, to each circuit of the circuit device 20, such as the oscillator circuit 30.

[0033] Figure 3 is an explanatory diagram of the positive voltage-capacitance characteristics of the first variable capacitance circuit 31, and Figure 4 is an explanatory diagram of the negative voltage-capacitance characteristics of the second variable capacitance circuit 32. The voltage-capacitance characteristics represent the characteristics of capacitance C with respect to the capacitance control voltage VCC. Note that Figures 3 and 4 schematically represent the voltage-capacitance characteristics, and in reality, the characteristics are not first-order characteristics as shown in Figures 3 and 4, but rather characteristics with an inflection point where the slope is maximum near the center of the variation range.

[0034] As shown in Figure 3, the first variable capacitance circuit 31 receives the first output voltage VQ1 from the switch circuit 36 ​​as a capacitance control voltage VCC. In the positive voltage capacitance characteristics of the first variable capacitance circuit 31, as the first output voltage VQ1 increases, the capacitance C increases, causing the oscillation frequency f of the oscillation circuit 30 to decrease. On the other hand, as shown in Figure 4, the second variable capacitance circuit 32 receives the second output voltage VQ2 from the switch circuit 36 ​​as a capacitance control voltage VCC. In the negative voltage capacitance characteristics of the second variable capacitance circuit 32, as the second output voltage VQ2 increases, the capacitance C decreases, causing the oscillation frequency f to increase.

[0035] The circuit device 20 of this embodiment shown in Figure 2 includes a temperature compensation circuit 40 that outputs a temperature compensation voltage VCP to temperature-compensate the oscillation frequency of the oscillation circuit 30. The first input voltage VI1 input to the switch circuit 36 ​​is the temperature compensation voltage VCP from the temperature compensation circuit 40. In this way, the temperature compensation voltage VCP from the temperature compensation circuit 40 is input to the first input terminal TI1 of the switch circuit 36 ​​as the first input voltage VI1, and this temperature compensation voltage VCP can be output as a first output voltage VQ1 to the first variable capacitor circuit 31 with positive characteristics, or as a second output voltage VQ2 to the second variable capacitor circuit 32 with negative characteristics. Therefore, the temperature compensation voltage VCP from the temperature compensation circuit 40 makes it possible to perform temperature compensation of the oscillation frequency with positive voltage-capacitance characteristics using the first variable capacitor circuit 31, or to perform temperature compensation of the oscillation frequency with negative voltage-capacitance characteristics using the second variable capacitor circuit 32.

[0036] Furthermore, the circuit device 20 in Figure 2 includes a frequency control circuit 50 that outputs a frequency control voltage VFC of the oscillation frequency of the oscillation circuit 30. The second input voltage VI2 is the frequency control voltage VFC from the frequency control circuit 50. In this way, the switch circuit 36 ​​receives the frequency control voltage VFC from the frequency control circuit 50 as the second input voltage VI2 at the second input terminal TI2, and this frequency control voltage VFC can be output as the second output voltage VQ2 to the negative-characteristic second variable capacitor circuit 32, or as the first output voltage VQ1 to the positive-characteristic first variable capacitor circuit 31. In this way, it becomes possible to control the oscillation frequency with a positive characteristic or the oscillation frequency with a negative characteristic using the frequency control voltage VFC from the frequency control circuit 50. For example, it becomes possible to control the oscillation frequency with a positive characteristic by increasing the oscillation frequency when the external control voltage VC increases, or to control the oscillation frequency with a negative characteristic by decreasing the oscillation frequency when the external control voltage VC increases. In this case, the frequency control circuit 50 does not need to be equipped with an inverting amplifier, for example, which is an inverting amplifier circuit, thus enabling smaller circuit size and lower power consumption.

[0037] Figure 2 shows the case where both the temperature compensation circuit 40 and the frequency control circuit 50 are provided, but it is also possible to implement a modified version where only one of the temperature compensation circuit 40 or the frequency control circuit 50 is provided. For example, if only the temperature compensation circuit 40 is provided without the frequency control circuit 50, it will be possible to realize a circuit device 20 or oscillator 4 that has a temperature compensation function but does not have a frequency control function based on the control voltage VC. Alternatively, if only the frequency control circuit 50 is provided without the temperature compensation circuit 40, it will be possible to realize a circuit device 20 or oscillator 4 that has a frequency control function based on the control voltage VC but does not have a temperature compensation function, as shown in the configuration of Figure 8 described later. In this case, the temperature compensation processing of the oscillation frequency may be performed by an external system, or an oscillator 4 such as an SPXO that does not have a temperature compensation function may be realized.

[0038] Furthermore, the multiple voltages that the switch circuit 36 ​​can select include fixed voltages. For example, in Figure 2, the multiple voltages include fixed voltages such as the reference voltage VREF and the ground voltage GND. The switch circuit 36 ​​then outputs these fixed voltages to the first output terminal TQ1 or the second output terminal TQ2. The fixed voltage only needs to be output to the first output terminal TQ1 or the second output terminal TQ2, and it is also possible for the fixed voltage to be output to both the first output terminal TQ1 and the second output terminal TQ2. In this way, by having the switch circuit 36 ​​output a fixed voltage to the first output terminal TQ1 or the second output terminal TQ2, the capacitance of the first variable capacitance circuit 31 or the second variable capacitance circuit 32 can be set to a fixed capacitance.

[0039] For example, when a fixed voltage is output from the first output terminal TQ1 of the switch circuit 36, the capacitance of the first variable capacitance circuit 31, to which this fixed voltage is input, is set to a fixed value. Therefore, for example, when a frequency control voltage VFC is output from the second output terminal TQ2 of the switch circuit 36, frequency control can be achieved by controlling the capacitance of the second variable capacitance circuit 32 based on the frequency control voltage VFC while keeping the capacitance of the first variable capacitance circuit 31 fixed. Also, for example, when a fixed voltage is output from the second output terminal TQ2 of the switch circuit 36, the capacitance of the second variable capacitance circuit 32, to which this fixed voltage is input, is set to a fixed value. Therefore, for example, when a temperature compensation voltage VCP is output from the first output terminal TQ1 of the switch circuit 36, temperature compensation can be achieved by controlling the capacitance of the first variable capacitance circuit 31 based on the temperature compensation voltage VCP while keeping the capacitance of the second variable capacitance circuit 32 fixed. Furthermore, for example, by outputting a fixed voltage from both the first output terminal TQ1 and the second output terminal TQ2 of the switch circuit 36, the capacitances of both the first variable capacitance circuit 31 and the second variable capacitance circuit 32, to which this fixed voltage is input, are set to a fixed value. This makes it possible to realize, for example, a circuit device 20 for an SPXO.

[0040] The switch circuit 36 ​​also outputs a fixed voltage, either a fixed voltage on the high-potential side or a fixed voltage on the low-potential side, to the first output terminal TQ1 or the second output terminal TQ2. The fixed voltage on the high-potential side is, for example, the reference voltage VREF in Figure 2. The fixed voltage on the low-potential side is, for example, the ground voltage GND in Figure 2. However, this embodiment is not limited to this, and the fixed voltage on the high-potential side may be the power supply voltage VDD, and the fixed voltage on the low-potential side may be a voltage lower than VDD or VREF and higher than GND. In this way, it becomes possible to fix the capacitances of the first variable capacitor circuit 31 and the second variable capacitor circuit 32 to high or low capacitances. For example, by outputting the fixed voltage on the high-potential side from the first output terminal TQ1, the capacitance of the positive-response first variable capacitor circuit 31 can be fixed to a large capacitance, and by outputting the fixed voltage on the low-potential side from the first output terminal TQ1, the capacitance of the positive-response first variable capacitor circuit 31 can be fixed to a small capacitance. Furthermore, the fixed voltage on the high-potential side is output from the second output terminal TQ2, which allows the capacitance of the negative-characteristic second variable capacitance circuit 32 to be fixed to a small capacitance, and the fixed voltage on the low-potential side is output from the second output terminal TQ2, which allows the capacitance of the negative-characteristic second variable capacitance circuit 32 to be fixed to a large capacitance.

[0041] Furthermore, the non-volatile memory 70 in Figure 2 stores the voltage selection setting information for the switch circuit 36. The voltage selection setting information is information that allows the switch circuit 36 ​​to set which of a plurality of voltages, including the first input voltage VI1 and the second input voltage VI2, will be output as the first output voltage VQ1 and the second output voltage VQ2. Specifically, the logic circuit 60 reads the voltage selection setting information from the non-volatile memory 70 and outputs a switch control signal to the switch circuit 36 ​​based on the voltage selection setting information. Then, based on the switch control signal from the logic circuit 60, the on / off control of the plurality of switch elements of the switch circuit 36 ​​is performed, so that the switch circuit 36 ​​outputs the first output voltage VQ1, which is selected from a plurality of voltages including the first input voltage VI1 and the second input voltage VI2, from the first output terminal TQ1, and outputs the second output voltage VQ2, which is selected from the plurality of voltages, from the second output terminal TQ2. In this way, based on the voltage selection setting information stored in the non-volatile memory 70, which can retain information even without a power supply, the voltage selected by the switch circuit 36 ​​can be output as the first output voltage VQ1 from the first output terminal TQ1, or as the second output voltage VQ2 from the second output terminal TQ2. The voltage selection setting information for the switch circuit 36 ​​may be stored using, for example, a fuse circuit. Alternatively, the voltage selection of the switch circuit 36 ​​may be set by changing the mask of metal wiring, etc.

[0042] 2. Switch Circuit Figure 5 shows an example of the configuration of the switch circuit 36. As shown in Figure 5, the switch circuit 36 ​​receives a first input voltage VI1 at the first input terminal TI1, a second input voltage VI2 at the second input terminal TI2, outputs a first output voltage VQ1 at the first output terminal TQ1, and outputs a second output voltage VQ2 at the second output terminal TQ2. In Figure 5, the switch circuit 36 ​​includes switch elements SW1, SW1D, SW1U, SW12, SW2, SW2D, SW2U, and SW21. The switch circuit 36 ​​also includes resistors R1 and R2, which are provided corresponding to the first output terminal TQ1 and the second output terminal TQ2.

[0043] Switch element SW1 is provided between node NS1 and node NS2, which are connected to the first input terminal TI1. Pull-down switch element SW1D is provided between the GND supply node and node NS2. Pull-up switch element SW1U is provided between the VREF supply node and node NS2. Switch element SW12 is provided between node NS2 and node NS3, which is connected to the second input terminal TI2. Resistor R1 is provided between node NS2 and the first output terminal TQ1.

[0044] Switch element SW2 is provided between node NS3 and node NS4, which are connected to the second input terminal TI2. Pull-down switch element SW2D is provided between the GND supply node and node NS4. Pull-up switch element SW2U is provided between the VREF supply node and node NS4. Switch element SW21 is provided between node NS4 and node NS1. Resistor R2 is provided between node NS4 and the second output terminal TQ2.

[0045] In the switch circuit 36 ​​of Figure 5, when switch element SW1 is turned on, the first input voltage VI1 is output as the first output voltage VQ1. When switch element SW2 is turned on, the second input voltage VI2 is output as the second output voltage VQ2. On the other hand, when switch element SW12 is turned on, the second input voltage VI2 is output as the first output voltage VQ1. When switch element SW21 is turned on, the first input voltage VI1 is output as the second output voltage VQ2. When switch element SW1D is turned on, the first output voltage VQ1 is set to a fixed voltage of GND, and when switch element SW1U is turned on, the first output voltage VQ1 is set to a fixed voltage of VREF. When switch element SW2D is turned on, the second output voltage VQ2 is set to a fixed voltage of GND, and when switch element SW2U is turned on, the second output voltage VQ2 is set to a fixed voltage of VREF. Here, GND is a fixed voltage on the low potential side, and VREF is a fixed voltage on the high potential side.

[0046] Figure 6 is an explanatory diagram of the setting of the operating mode by the switch circuit 36 ​​in Figure 5. In Figure 6, "1" indicates that each switch element SW1, SW1D, SW1U, SW12, SW2, SW2D, SW2U, and SW21 are ON, and "0" indicates that each switch element is OFF. Also, in Figure 5, it is assumed that the temperature compensation voltage VCP is input as the first input voltage VI1 and the frequency control voltage VFC is input as the second input voltage VI2, as shown in Figure 2.

[0047] As shown in Figure 6, when the switch elements SW1 and SW2 are ON, the first output voltage VQ1 and the second output voltage VQ2 are output as temperature compensation voltage VCP and frequency control voltage VFC, respectively. This sets the first variable capacitance circuit 31 to be used for temperature compensation and the second variable capacitance circuit 32 to be used for frequency control, setting the VC-TCXO mode. This makes it possible to realize a VC-TCXO that performs temperature compensation by the temperature compensation voltage VCP and frequency control by the frequency control voltage VFC.

[0048] On the other hand, when switch element SW1 is ON, and switch element SW2D or SW2U is ON, the TCXO is set to a mode where the temperature compensation voltage VCP is output as the first output voltage VQ1 to the positive-characteristic first variable capacitance circuit 31, and a fixed voltage of GND or VREF is output as the second output voltage VQ2 to the second variable capacitance circuit 32. The negative-characteristic second variable capacitance circuit 32 is fixed to a high load capacitance CL when GND is input as the second output voltage VQ2, and fixed to a low load capacitance CL when VREF is input as the second output voltage VQ2. As a result, a TCXO can be realized in which frequency control is not performed by the frequency control voltage VFC, but temperature compensation is performed by the temperature compensation voltage VCP.

[0049] Furthermore, when switch element SW2 is ON, and switch element SW1D or SW1U is ON, the VCXO mode is set in which the frequency control voltage VFC is output as the second output voltage VQ2 to the negative-characteristic second variable capacitance circuit 32, and the fixed voltage GND or VREF is output as the first output voltage VQ1 to the first variable capacitance circuit 31. The positive-characteristic first variable capacitance circuit 31 is fixed to a low load capacitance CL when GND is input as the first output voltage VQ1, and fixed to a high load capacitance CL when VREF is input as the first output voltage VQ1. As a result, a VCXO can be realized in which temperature compensation is not performed by the temperature compensation voltage VCP, but frequency control is performed by the frequency control voltage VFC.

[0050] Furthermore, when switch element SW1D or SW1U is ON, and switch element SW2D or SW2U is also ON, the SPXO mode is set in which a fixed voltage of GND or VREF is output to the first variable capacitance circuit 31 as the first output voltage VQ1, and GND or VREF is output to the second variable capacitance circuit 32 as the second output voltage VQ2. The positive-response first variable capacitance circuit 31 is fixed to a low load capacitance CL and a high load capacitance CL, respectively, when GND and VREF are input. Similarly, the negative-response second variable capacitance circuit 32 is fixed to a high load capacitance CL and a low load capacitance CL, respectively, when GND and VREF are input. As a result, the load capacitance CL of both the first variable capacitance circuit 31 and the second variable capacitance circuit 32 is fixed, and an SPXO can be realized without temperature compensation by the temperature compensation voltage VCP or frequency control by the frequency control voltage VFC.

[0051] Furthermore, when switch element SW21 is ON, and switch element SW1D or SW1U is ON, the temperature compensation voltage VCP is output as the second output voltage VQ2 to the negative-characteristic second variable capacitance circuit 32, and GND or VREF is output as the first output voltage VQ1 to the first variable capacitance circuit 31, setting the device to an inverting TCXO mode. The positive-characteristic first variable capacitance circuit 31 is fixed to a low load capacitance CL and a high load capacitance CL, respectively, when GND and VREF are input. In this way, by outputting the temperature compensation voltage VCP to the negative-characteristic second variable capacitance circuit 32, temperature compensation can be performed using the temperature compensation voltage VCP with characteristics opposite to those of a normal TCXO, thus realizing an inverting TCXO with inverted temperature compensation. For example, this inverting TCXO mode is useful when the frequency-temperature characteristics of the oscillator 10 are opposite to those shown in Figure 17, which will be described later.

[0052] Furthermore, when switch element SW12 is ON, and switch element SW2D or SW2U is also ON, the system is set to an inverting VCXO mode in which the frequency control voltage VFC is output as the first output voltage VQ1 to the positive-characteristic first variable capacitor circuit 31, and GND or VREF is output as the second output voltage VQ2 to the second variable capacitor circuit 32. The negative-characteristic second variable capacitor circuit 32 is fixed to a high load capacitance CL and a low load capacitance CL, respectively, when GND and VREF are input. As a result, the frequency control can be performed by the frequency control voltage VFC with characteristics opposite to those of a normal VCXO, and an inverting VCXO with inverted frequency control can be realized. In this inverting VCXO, when the frequency control voltage VFC rises due to an increase in an external control voltage VC, the capacitance of the positive-characteristic first variable capacitor circuit 31 to which the frequency control voltage VFC is input increases, and the oscillation frequency decreases. When the frequency control voltage VFC decreases, the capacitance of the first variable capacitor circuit 31 decreases, and the oscillation frequency increases. Therefore, an inverting VCXO, in which the oscillation frequency decreases when the frequency control voltage VFC increases and increases when the frequency control voltage VFC decreases, can be realized without, for example, providing an inverting amplifier in the frequency control circuit 50. As a result, it becomes possible to realize an inverting VCXO while reducing the size of the circuit and the power consumption.

[0053] Furthermore, when switch element SW12 is ON and switch element SW21 is also ON, the system is set to an inverting VC-inverting TCXO mode, where the frequency control voltage VFC is output as the first output voltage VQ1 to the first variable capacitance circuit 31 with positive characteristics, and the temperature compensation voltage VCP is output as the second output voltage VQ2 to the second variable capacitance circuit 32 with negative characteristics. In this inverting VC-inverting TCXO, when the frequency control voltage VFC increases due to an increase in the control voltage VC, the capacitance of the first variable capacitance circuit 31 to which the frequency control voltage VFC is input increases, causing the oscillation frequency to decrease. When the control voltage VC decreases, the capacitance of the first variable capacitance circuit 31 to which the frequency control voltage VFC is input decreases, causing the oscillation frequency to increase, thus realizing an inverting VCXO. Moreover, since the temperature compensation voltage VCP is output to the second variable capacitance circuit 32 with negative characteristics, temperature compensation by the temperature compensation voltage VCP can be performed with characteristics of the opposite polarity to a normal TCXO, realizing an inverting TCXO with inverted temperature compensation. Therefore, it becomes possible to realize an inverted VC-inverted TCXO, which is both an inverted VCXO and an inverted TCXO.

[0054] As described above, the circuit device 20 of this embodiment includes a temperature compensation circuit 40 that outputs a temperature compensation voltage VCP to temperature-compensate the oscillation frequency of the oscillation circuit 30 based on the temperature detection result of the temperature sensor 48, and a frequency control circuit 50 that outputs a frequency control voltage VFC of the oscillation frequency. In the first mode, the switch circuit 36 ​​outputs the temperature compensation voltage VCP to the first output terminal TQ1 and the frequency control voltage VFC to the second output terminal TQ2. This first mode corresponds to, for example, the mode of the VC-TCXO in Figure 6. When the operating mode of the circuit device 20 is set to the first mode, the temperature compensation voltage VCP from the temperature compensation circuit 40 is supplied to the first variable capacitor circuit 31 with positive characteristics, and the frequency control voltage VFC from the frequency control circuit 50 is supplied to the second variable capacitor circuit 32 with negative characteristics. Therefore, when temperature compensation is performed by the temperature compensation voltage VCP and the frequency control voltage VFC increases, the capacitance of the negative-characteristic second variable capacitance circuit 32 decreases, causing the oscillation frequency to increase. When the frequency control voltage VFC decreases, the capacitance of the second variable capacitance circuit 32 increases, causing the oscillation frequency to decrease. Thus, it becomes possible to provide a circuit device 20 for a VC-TCXO that can perform both temperature compensation by the temperature compensation voltage VCP and frequency control by the frequency control voltage VFC.

[0055] In the second mode, the switch circuit 36 ​​outputs a temperature compensation voltage VCP to the first output terminal TQ1 and a first fixed voltage to the second output terminal TQ2. This second mode corresponds to, for example, the mode of the TCXO in Figure 6. The first fixed voltage is, for example, a low-potential voltage such as the ground voltage GND or a high-potential voltage such as the reference voltage VREF. By setting the operating mode of the circuit device 20 to the second mode, the temperature compensation voltage VCP from the temperature compensation circuit 40 is supplied to the first variable capacitance circuit 31 with positive characteristics, and the first fixed voltage is supplied to the second variable capacitance circuit 32 as a capacitance control voltage. Therefore, temperature compensation is performed by the capacitance change of the first variable capacitance circuit 31 based on the temperature compensation voltage VCP, and the capacitance of the second variable capacitance circuit 32 is fixed. Thus, it is possible to provide a circuit device 20 for a TCXO in which frequency control is not performed by the frequency control voltage VFC, but temperature compensation is performed by the temperature compensation voltage VCP.

[0056] In the third mode, the switch circuit 36 ​​outputs a second fixed voltage to the first output terminal TQ1 and a frequency control voltage VFC to the second output terminal TQ2. This third mode corresponds to, for example, the mode of the VCXO in Figure 6. The second fixed voltage is, for example, a low-potential voltage such as GND or a high-potential voltage such as VREF. By setting the operating mode of the circuit device 20 to the third mode, the frequency control voltage VFC from the frequency control circuit 50 is supplied to the negative-characteristic second variable capacitor circuit 32, and the second fixed voltage is supplied to the first variable capacitor circuit 31 as a capacitance control voltage. Therefore, frequency control is performed by the capacitance change of the second variable capacitor circuit 32 based on the frequency control voltage VFC, and the capacitance of the first variable capacitor circuit 31 is fixed. Thus, it is possible to provide a circuit device 20 for a VCXO in which temperature compensation is not performed by the temperature compensation voltage VCP, but frequency control is performed by the frequency control voltage VFC.

[0057] In the fourth mode, the switch circuit 36 ​​outputs a third fixed voltage to the first output terminal TQ1 and a fourth fixed voltage to the second output terminal TQ2. This fourth mode corresponds to, for example, the mode of the SPXO in Figure 6. The third and fourth fixed voltages are, for example, low-potential voltages such as GND or high-potential voltages such as VREF. By setting the operating mode of the circuit device 20 to the fourth mode, the third fixed voltage is supplied to the first variable capacitance circuit 31 as a capacitance control voltage, and the fourth fixed voltage is supplied to the second variable capacitance circuit 32 as a capacitance control voltage. Therefore, the capacitances of the first variable capacitance circuit 31 and the second variable capacitance circuit 32 are fixed, making it possible to provide a circuit device 20 for an SPXO that does not perform temperature compensation or frequency control based on the frequency control voltage VFC.

[0058] In the fifth mode, the switch circuit 36 ​​outputs a frequency control voltage VFC to the first output terminal TQ1 and a fifth fixed voltage or temperature compensation voltage VCP to the second output terminal TQ2. This fifth mode corresponds to, for example, the inverting VCXO mode or the inverting VC-inverting TCXO mode shown in Figure 6. The fifth fixed voltage is, for example, a low-potential voltage such as GND or a high-potential voltage such as VREF. When the operating mode of the circuit device 20 is set to the fifth mode, the frequency control voltage VFC from the frequency control circuit 50 is supplied to the positive-characteristic first variable capacitor circuit 31, and the fifth fixed voltage or temperature compensation voltage VCP is supplied to the negative-characteristic second variable capacitor circuit 32. Therefore, when the frequency control voltage VFC increases, the capacitance of the positive-characteristic first variable capacitor circuit 31 increases, causing the oscillation frequency to decrease, and when the frequency control voltage VFC decreases, the capacitance of the first variable capacitor circuit 31 decreases, causing the oscillation frequency to increase. On the other hand, in the second variable capacitance circuit 32, the capacitance is fixed by the supply of the fifth fixed voltage, and frequency adjustment for temperature compensation is performed based on the temperature compensation voltage VCP. In this way, an inverting VCXO, in which the oscillation frequency decreases when the frequency control voltage VFC increases and increases when the frequency control voltage VFC decreases, can be realized without, for example, providing an inverting amplifier.

[0059] The configuration of the switch circuit 36 ​​is not limited to the configuration in Figure 5, and various modifications are possible. For example, the switch circuit 36 ​​may be a circuit in which the first output voltage VQ1 and the second output voltage VQ2 cannot be set to fixed voltages such as VREF or GND. Also, for example, the switch circuit 36 ​​may have a configuration as shown in Figure 7. In Figure 7, in addition to the first input terminal TI1 and the second input terminal TI2, a third input terminal TI3 is provided, and in addition to the first output terminal TQ1 and the second output terminal TQ2, a third output terminal TQ3 is provided. In Figure 7, the first input voltage VI1 is input to the first input terminal TI1, the second input voltage VI2 is input to the second input terminal TI2, and the third input voltage VI3 is input to the third input terminal TI3. The switch circuit 36 ​​outputs a first output voltage VQ1, selected from a plurality of voltages including the first input voltage VI1, the second input voltage VI2, and the third input voltage VI3, to the first output terminal TQ1; a second output voltage VQ2, selected from the plurality of voltages, to the second output terminal TQ2; and a third output voltage VQ3, selected from the plurality of voltages, to the third output terminal TQ3. The switch circuit 36 ​​is further provided with switch elements SW3, SW3D, SW3U, SW31, and SW32 to enable the input of the third input voltage VI3 and the output of the third output voltage VQ3. Thus, the switch circuit 36 ​​may have three or more input terminals and three or more output terminals.

[0060] Furthermore, the circuit device 20 of this embodiment does not need to have all of the first to fifth operating modes described above; for example, it may have at least two of the first to fifth operating modes. For example, the circuit device 20 of this embodiment does not necessarily need to have both the temperature compensation circuit 40 and the frequency control circuit 50; for example, it is possible to implement a modified version that has only one of the circuits, the temperature compensation circuit 40 or the frequency control circuit 50.

[0061] For example, Figure 8 shows another detailed configuration example of the circuit device 20 and oscillator 4 of this embodiment. In Figure 8, a frequency control circuit 50 is provided, but a temperature compensation circuit 40 is not. The oscillation circuit 30 includes a first variable capacitance circuit 31 with positive characteristics and a second variable capacitance circuit 32 with negative characteristics. In the first mode, the frequency control voltage VFC is input to the second variable capacitance circuit 32 as the capacitance control voltage, and in the second mode, the frequency control voltage VFC is input to the first variable capacitance circuit 31 as the capacitance control voltage.

[0062] In this way, by setting the operating mode of the circuit device 20 to the first mode, when the frequency control voltage VFC increases, the capacitance of the negative-characteristic second variable capacitor circuit 32 to which the frequency control voltage VFC is input decreases, causing the oscillation frequency to increase. When the frequency control voltage VFC decreases, the capacitance of the second variable capacitor circuit 32 increases, causing the oscillation frequency to decrease. Therefore, by setting the operating mode of the circuit device 20 to the first mode, it becomes possible to realize a normal VCXO in which the oscillation frequency increases when the frequency control voltage VFC increases and decreases when the frequency control voltage VFC decreases.

[0063] Furthermore, by setting the operating mode of the circuit device 20 to the second mode, when the frequency control voltage VFC increases, the capacitance of the positive-response first variable capacitor circuit 31, to which this frequency control voltage VFC is input, increases, causing the oscillation frequency to decrease. Conversely, when the frequency control voltage VFC decreases, the capacitance of the first variable capacitor circuit 31 decreases, causing the oscillation frequency to increase. Therefore, by setting the operating mode of the circuit device 20 to the second mode, an inverting VCXO, etc., in which the oscillation frequency decreases when the frequency control voltage VFC increases and the oscillation frequency increases when the frequency control voltage VFC decreases, can be realized without, for example, providing an inverting amplifier in the frequency control circuit 50. In Figure 8, for example, the switch circuit 36 ​​(not shown) can output the frequency control voltage VFC input from the frequency control circuit 50 to the second variable capacitor circuit 32 via the second output terminal TQ2 in the first mode, and output the frequency control voltage VFC input from the frequency control circuit 50 to the first variable capacitor circuit 31 via the first output terminal TQ1 in the second mode.

[0064] As described above, according to this embodiment, by providing the switch circuit 36, it becomes possible to operate the circuit device 20 in various operating modes. For example, a circuit device 20 with a common design platform can realize various operating modes such as VC-TCXO, TCXO, VCXO, SPXO, inverting VCXO, or inverting TCXO. In this way, it becomes unnecessary to design a separate circuit device 20 dedicated to each of these multiple operating modes. Furthermore, by, for example, storing setting information for voltage selection in the non-volatile memory 70, setting fuses using a fuse circuit, or switching mask layers such as a metal layer, it becomes possible to operate the circuit device 20 with the same common platform in the desired operating mode. This makes it possible to provide circuit devices 20 and oscillators 4 with various operating modes while shortening the development period and reducing development costs.

[0065] 3. Oscillator Circuit Next, the details of the oscillation circuit 30 will be described. Figure 9 shows a first configuration example of the oscillation circuit 30. In the following explanation, we will mainly use the case where the operating mode of the circuit device 20 is set to the first mode, which is the mode of the VC-TCXO in Figure 6, as an example. In the first mode, as shown in Figure 9, the temperature compensation voltage VCP from the temperature compensation circuit 40 and the frequency control voltage VFC from the frequency control circuit 50 are input to the switch circuit 36 ​​as the first input voltage VI1 and the second input voltage VI2, respectively. The switch circuit 36 ​​then outputs the temperature compensation voltage VCP and the frequency control voltage VFC as the first output voltage VQ1 and the second output voltage VQ2 to the first variable capacitor circuit 31 and the second variable capacitor circuit 32, respectively.

[0066] The oscillator circuit 30 in Figure 9 includes a drive circuit DV, a resistor RA, a first variable capacitance circuit 31, and a second variable capacitance circuit 32. The oscillator circuit 30 may also include a capacitor CB5 provided between the temperature compensation voltage VCP supply node and the low-potential side power supply node, and a capacitor CB6 provided between the frequency control voltage VFC supply node and the low-potential side power supply node. The low-potential side power supply node is, for example, a ground node. One end of the oscillator 10 of the drive circuit DV is connected to node N1, which is its input node, via pad PX1, and the other end of the oscillator 10 is connected to node N2, which is its output node, via pad PX2. The resistor RA, which is a feedback element from the output to the input of the drive circuit DV, has one end connected to node N1 and the other end connected to node N2. In Figure 9, the first variable capacitance circuit 31 and the second variable capacitance circuit 32 are provided at both node N1, to which one end of the oscillator 10 is connected via pad PX1, and node N2, to which the other end of the oscillator 10 is connected via pad PX2. However, the first variable capacitance circuit 31 and the second variable capacitance circuit 32 may be provided at only one of nodes N1 or N2.

[0067] In Figure 9, the first variable capacitance circuit 31 is composed of transistor TR1, and the second variable capacitance circuit 32 is composed of transistor TR2. Transistors TR1 and TR2 are MOS (Metal Oxide Semiconductor) type variable capacitance elements, also known as MOS varactors. In Figure 9, the first variable capacitance circuit 31 and the second variable capacitance circuit 32 are composed of N-type transistors TR1 and TR2, respectively. A MOS type variable capacitance element is a capacitance element in which the source and drain of a MOS transistor are short-circuited, and the capacitance generated between the short-circuited source and drain and the gate is variably controlled by a capacitance control voltage.

[0068] In the following explanation, we will mainly use the example where each of the first variable capacitance circuit 31 and the second variable capacitance circuit 32 is composed of a single transistor, which is a MOS-type variable capacitance element. However, they may also be composed of two or more transistors connected in parallel. Furthermore, it is possible to implement a variation using P-type transistors as the transistors constituting the first variable capacitance circuit 31 and the second variable capacitance circuit 32. In the following explanation, we will mainly use the configuration of the first variable capacitance circuit 31 and the second variable capacitance circuit 32 provided at node N1 as an example. The configuration of the first variable capacitance circuit 31 and the second variable capacitance circuit 32 connected to node N2 is the same, so a detailed explanation will be omitted.

[0069] The transistor TR1 of the first variable capacitance circuit 31 on the node N1 side has its gate supplied with a temperature compensation voltage VCP from the temperature compensation circuit 40, and its source and drain are connected to node N1. This realizes a variable capacitance circuit with a positive voltage-capacitance characteristic as shown in Figure 3, where the load capacitance of node N1 increases when the temperature compensation voltage VCP rises, and decreases when the temperature compensation voltage VCP falls. Consequently, the oscillation frequency decreases when the temperature compensation voltage VCP rises, and increases when the temperature compensation voltage VCP falls. As a result, for the third-order frequency-temperature characteristic of the oscillator 10 shown in Figure 17, the temperature compensation voltage VCP shown in Figure 19 cancels out the increase or decrease in the oscillation frequency, enabling temperature compensation that keeps the oscillation frequency constant.

[0070] The transistor TR2 of the second variable capacitance circuit 32 on the node N1 side has the frequency control voltage VFC from the frequency control circuit 50 supplied to its source and drain, and its gate is connected to node N1. This realizes a variable capacitance circuit with a negative voltage capacitance characteristic as shown in Figure 4, where the load capacitance of node N1 decreases when the frequency control voltage VFC increases, and increases when the frequency control voltage VFC decreases. Therefore, the oscillation frequency increases when the frequency control voltage VFC increases, and decreases when the frequency control voltage VFC decreases. Thus, it becomes possible to realize a VC-TCXO, which is a voltage-controlled temperature-compensated oscillator that can control the oscillation frequency of the oscillation circuit 30 based on an external control voltage VC.

[0071] Figure 10 shows a second example configuration of the oscillator circuit 30. Note that the oscillator circuit 30 is not limited to the configurations shown in Figures 9 and 10, and various modifications can be made, such as omitting some of the components, adding other components, or replacing some components with other components.

[0072] In the second configuration example shown in Figure 10, the first variable capacitance circuit 31 on the node N1 side is composed of transistor TR1, and the second variable capacitance circuit 32 on the node N1 side is composed of transistor TR2. The first variable capacitance circuit 31 is electrically connected to node N1 via DC-blocking capacitor CB1, and the second variable capacitance circuit 32 is electrically connected to node N1 via DC-blocking capacitor CB2. Figure 10 also shows a reference voltage generation circuit 34 that generates reference voltages VR1 and VR2. The first variable capacitance circuit 31 and the second variable capacitance circuit 32 on the node N2 side are connected to node N2 via capacitors CB3 and CB4, but since these variable capacitance circuits have the same configuration as the first variable capacitance circuit 31 and the second variable capacitance circuit 32 on the node N1 side, a detailed explanation is omitted.

[0073] The first variable capacitance element, transistor TR1, and capacitor CB1 are connected in series between the reference voltage VR1 supply node and node N1. Specifically, one end of capacitor CB1 is connected to node N1, and the other end is connected to the gate of transistor TR1, supplying the reference voltage VR1 to the source and drain of transistor TR1. The temperature compensation circuit 40 supplies a temperature compensation voltage VCP to the connection node of capacitor CB1 and transistor TR1 via the switch circuit 36.

[0074] The second variable capacitance element, transistor TR2, and capacitor CB2 are connected in series between the reference voltage VR2 supply node and node N1. Specifically, one end of capacitor CB2 is connected to node N1, and the other end is connected to the source and drain of transistor TR2, supplying the reference voltage VR2 to the gate of transistor TR2. The frequency control circuit 50 also supplies a frequency control voltage VFC to the connection node of capacitor CB2 and transistor TR2 via the switch circuit 36.

[0075] In Figure 10, the first variable capacitance circuit 31 may be composed of multiple transistors TR1 arranged in parallel, and the second variable capacitance circuit 32 may be composed of multiple transistors TR2 arranged in parallel. In this case, multiple reference voltages VR1 of different voltages should be supplied to the sources and drains of the multiple transistors TR1 that constitute the first variable capacitance circuit 31. Similarly, multiple reference voltages VR2 of different voltages should be supplied to the gates of the multiple transistors TR2 that constitute the second variable capacitance circuit 32. By doing so, the linearity characteristics of the total capacitance of the first variable capacitance circuit 31 can be improved by superimposing the different voltage capacitance characteristics of the multiple transistors TR1. Similarly, the linearity characteristics of the total capacitance of the second variable capacitance circuit 32 can be improved by superimposing the different voltage capacitance characteristics of the multiple transistors TR2.

[0076] As shown in Figure 11, the transistor TR1 constituting the first variable capacitance circuit 31 has a temperature compensation voltage VCP supplied to its gate and a reference voltage VR1 supplied to its source and drain. As a result, as shown in Figure 12, the voltage capacitance characteristic of the first variable capacitance circuit 31 is positive with respect to the gate-drain voltage VGD = VCP - VR1. Therefore, as shown in Figure 13, the voltage capacitance characteristic of the first variable capacitance circuit 31 is also positive with respect to the temperature compensation voltage VCP. Specifically, in Figure 13, the voltage capacitance characteristic is positive with respect to the reference voltage VR1, as shown in B1, compared to Figure 12.

[0077] In Figures 12 and 13, Vth is the threshold voltage of transistor TR1. As mentioned earlier, the voltage-capacitance characteristic has its maximum slope near the center of the range of change, and in Figure 12, the slope of the voltage-capacitance characteristic is maximum when VGD = Vth. On the other hand, in Figure 13, the slope of the voltage-capacitance characteristic is maximum when VCP = Vth + VR1.

[0078] As shown in Figure 14, the transistor TR2 constituting the second variable capacitance circuit 32 has a frequency control voltage VFC supplied to its source and drain, and a reference voltage VR2 supplied to its gate. As a result, as shown in Figure 15, the voltage capacitance characteristic of the second variable capacitance circuit 32 is positive with respect to the gate-drain voltage VGD = VR2 - VFC. In Figure 15, Vth is the threshold voltage of transistor TR2. Therefore, as shown in Figure 16, the voltage capacitance characteristic of the second variable capacitance circuit 32 is negative with respect to the frequency control voltage VFC. Specifically, in Figure 16, the polarity is reversed compared to Figure 15, and the voltage capacitance characteristic is shifted by the reference voltage VR2 as shown in B2, resulting in a negative characteristic.

[0079] Figure 17 shows the frequency-temperature characteristics of the oscillator 10. Specifically, it shows the frequency-temperature characteristics of an AT-cut quartz oscillator 10, for example. As shown in Figure 17, the oscillator 10 has frequency-temperature characteristics that can be approximated by a cubic curve. When adjusting the capacitance of such an oscillator 10 using a second variable capacitance circuit 32 with negative voltage-capacitance characteristics, the temperature compensation circuit 40 needs to output a temperature compensation voltage VCP with temperature characteristics as shown in Figure 18, for example. In this way, when the oscillation frequency of the oscillator 10 rises in the high-temperature range as shown in A1 of Figure 17, the temperature compensation voltage VCP output from the temperature compensation circuit 40 becomes lower as shown in A2 of Figure 18. As a result, the capacitance of the negative-characteristic second variable capacitance circuit 32 increases, and the rise in the oscillation frequency of the oscillator 10 is canceled out, thereby achieving temperature compensation that keeps the oscillation frequency constant.

[0080] However, in the high-temperature range shown in A2 of Figure 18, in order to sufficiently reduce the temperature compensation voltage VCP, it is necessary to widen the low-voltage operating range of the output amplifier of the temperature compensation circuit 40. For this reason, it is difficult to widen the low-voltage operating range with the Class A amplifier circuit shown in Figure 21, described later, as the output amplifier of the temperature compensation circuit 40. Therefore, it is necessary to use a Class AB amplifier circuit as shown in Figure 22, described later, which complicates the circuit and increases its size.

[0081] On the other hand, when adjusting the capacitance of the oscillator 10 using a first variable capacitance circuit 31 with a positive voltage capacitance characteristic, the temperature compensation circuit 40 should output a temperature compensation voltage VCP with a temperature characteristic as shown in Figure 19, for example. In this way, when the oscillation frequency of the oscillator 10 rises in the high-temperature range as shown in A1 of Figure 17, the temperature compensation voltage VCP output from the temperature compensation circuit 40 will rise as shown in A3 of Figure 19. As a result, the capacitance of the first variable capacitance circuit 31 with a positive characteristic will increase, and the rise in the oscillation frequency of the oscillator 10 will be offset, thereby enabling temperature compensation that keeps the oscillation frequency constant.

[0082] In this case, in the high-temperature range shown in A3 of Figure 19, the temperature compensation circuit 40 needs to extend the high-voltage operating range of its output amplifier in order to output a high-voltage temperature compensation voltage VCP. In this regard, even with the Class A amplifier circuit shown in Figure 21, which will be described later, the high-voltage temperature compensation voltage VCP shown in A3 of Figure 19 can be properly output by ensuring that the P-type drive transistor constituting the output section is sufficiently turned on. Therefore, it becomes unnecessary to use a Class AB amplifier circuit as shown in Figure 22 as the output amplifier of the temperature compensation circuit 40, making it possible to reduce the size and simplify the circuit.

[0083] Thus, the temperature compensation circuit 40 of this embodiment can include a Class A amplifier circuit that outputs a temperature compensation voltage VCP. The Class A amplifier circuit includes, for example, a differential section having differential inputs and an output section connected to the differential section, wherein the output section is an amplifier circuit having a P-type drive transistor and a current source transistor connected in series between a high-potential side power supply node and a low-potential side power supply node. In this way, proper temperature compensation of the oscillation frequency over a wide temperature range can be achieved by the temperature compensation circuit 40, which includes a Class A amplifier circuit that has a smaller circuit size and simpler configuration compared to a Class AB amplifier circuit, making it possible to achieve both proper temperature compensation and circuit miniaturization.

[0084] For example, oscillator 10 has a frequency-temperature characteristic that can be approximated by a cubic curve as shown in Figure 17. For example, oscillator 10 has a frequency-temperature characteristic that can be approximated by a polynomial such as a cubic polynomial. Furthermore, in the uncompensated state shown in Figure 17, oscillator 10 is an oscillator in which the oscillation frequency fh at the upper limit of the operating temperature range shown in A1 is greater than the maximum value fa of the oscillation frequency shown in A4. The operating temperature range is the temperature range in which the oscillator 4 and circuit device 20 can satisfy the specified characteristics.

[0085] For example, in the third-order frequency-temperature characteristics of oscillator 10 shown in Figure 17, the oscillation frequency reaches a maximum value fa at temperature Ta, as shown in A4, and a minimum value fb at temperature Tb, as shown in A5. The third-order frequency-temperature characteristics of oscillator 10 have an inflection point between temperatures Ta and Tb, for example, around 25°C. Therefore, the high-temperature range of the operating temperature range is wider than the low-temperature range. For example, if the operating temperature range is -40°C to 125°C, the high-temperature range is 25°C to 125°C, which is wider than the low-temperature range of -40°C to 25°C. The same applies when the operating temperature range is -40°C to 100°C. The oscillation frequency fh shown in A1 of Figure 17 is the oscillation frequency at the upper limit of the operating temperature range, for example, the oscillation frequency between 125°C and 100°C. Therefore, in Figure 17, the relationship holds that the oscillation frequency fh at the upper limit of the operating temperature range is greater than the maximum value fa of the oscillation frequency. In this case, for oscillator 10 where the oscillation frequency fh at the upper limit of the operating temperature range is greater than the maximum value fa of the oscillation frequency, the temperature range on the high-temperature side is wider than the temperature range on the low-temperature side.

[0086] Therefore, if a second variable capacitance circuit 32 with negative characteristics is used as the variable capacitance circuit to which the temperature compensation voltage VCP is input, as shown in A2 of Figure 18, it becomes necessary to widen the operating range on the low-voltage side of the output amplifier of the temperature compensation circuit 40 in order to sufficiently reduce the temperature compensation voltage VCP at the upper limit of the operating temperature range, and a Class AB amplifier circuit is required. In contrast, in this embodiment, a first variable capacitance circuit 31 with positive characteristics is used as the variable capacitance circuit to which the temperature compensation voltage VCP is input. Therefore, even if a Class A amplifier circuit is used as the output amplifier of the temperature compensation circuit 40, as shown in A3 of Figure 19, it becomes possible to sufficiently increase the temperature compensation voltage VCP at the upper limit of the operating temperature range, making it possible to achieve both appropriate temperature compensation and miniaturization of the circuit.

[0087] 4.Temperature compensation circuit Figure 20 shows an example of the configuration of the temperature compensation circuit 40. Note that the temperature compensation circuit 40 is not limited to the configuration shown in Figure 20; various modifications are possible, such as omitting some of these components, adding other components, or replacing some components with other components.

[0088] The temperature compensation circuit 40 is a circuit that outputs a temperature compensation voltage VCP by polynomial approximation with temperature as the variable. This temperature compensation circuit 40 includes a current generation circuit 42 and a current-voltage conversion circuit 46. The current generation circuit 42 generates a function current based on the temperature detection result of the temperature sensor 48. For example, the current generation circuit 42 generates a function current to temperature compensate for the frequency-temperature characteristics of the oscillator 10 as shown in Figure 17, based on the temperature detection voltage VTS, which is the temperature detection result from the temperature sensor 48. The current-voltage conversion circuit 46 then converts the function current from the current generation circuit 42 into a voltage and outputs the temperature compensation voltage VCP. Specifically, the current-voltage conversion circuit 46 outputs the temperature compensation voltage VCP using a Class A amplifier circuit AM.

[0089] The current generation circuit 42 includes a first-order correction circuit 43 and a higher-order correction circuit 44. The first-order correction circuit 43 outputs a first-order current that approximates a first-order function based on the temperature detection voltage VTS. For example, the first-order correction circuit 43 outputs a first-order function current based on first-order correction data corresponding to the first-order coefficients of the polynomial in the polynomial approximation. The first-order correction circuit 43 includes, for example, an operational amplifier, a first variable resistor circuit, a second variable resistor circuit, and a third variable resistor circuit. The operational amplifier, the first variable resistor circuit, and the second variable resistor circuit constitute a forward rotation amplifier circuit. The forward rotation amplifier circuit amplifies the temperature detection voltage VTS with reference to, for example, a reference voltage VRC. The forward rotation amplifier circuit outputs a first-order current to the input node of the current-voltage conversion circuit 46 via the third variable resistor circuit.

[0090] The higher-order correction circuit 44 outputs a higher-order current that approximates a higher-order function to the current-voltage conversion circuit 46 based on the temperature detection voltage VTS. For example, the higher-order correction circuit 44 outputs a higher-order current based on higher-order correction data corresponding to the higher-order coefficients of the polynomial in the polynomial approximation. As an example, the higher-order correction circuit 44 outputs a cubic current that approximates a cubic function. In this case, the higher-order correction circuit 44 includes a first differential circuit that performs differential operation based on the temperature detection voltage VTS, and a second differential circuit that outputs a cubic current by performing differential operation based on the output voltage of the first differential circuit and the temperature detection voltage VTS. In Figure 20, the temperature sensor 48 performs offset correction of the temperature detection voltage VTS based on zero-order correction data corresponding to the zero-order coefficients of the polynomial. That is, the temperature sensor 48 adjusts the offset of the temperature detection voltage VTS by the amount of the offset indicated by the zero-order correction data. The offset correction of the temperature detection voltage VTS corresponds to zero-order correction in temperature compensation of the oscillation frequency. Furthermore, the higher-order correction circuit 44 may further include correction circuits that perform corrections of the fourth order or higher. For example, the higher-order correction circuit 44 may further include a fourth-order correction circuit that outputs a fourth-order current approximating a fourth-order function, and a fifth-order correction circuit that outputs a fifth-order current approximating a fifth-order function.

[0091] The current-voltage conversion circuit 46 adds the primary current and higher-order currents, and outputs a temperature compensation voltage VCP by converting the added current into a current-voltage. This generates a temperature compensation voltage VCP that approximates a polynomial function.

[0092] The current-voltage conversion circuit 46 includes an amplifier circuit AM, a resistor RC, and a capacitor CC. The amplifier circuit AM is implemented by an operational amplifier. The resistor RC and capacitor CC are connected in parallel between the output terminal and the inverting input terminal of the amplifier circuit AM. A reference voltage VRC is input to the non-inverting input terminal of the amplifier circuit AM. As a result, the current-voltage conversion circuit 46 outputs a temperature-compensated voltage VCP by the amplifier circuit AM, for example, operating in Class A mode.

[0093] With this configuration of temperature compensation circuit 40, the function current generated by the current generation circuit 42 based on the temperature detection result of the temperature sensor 48 can be converted into a voltage by the current-voltage conversion circuit 46 and output as a temperature compensation voltage VCP. Since the current-voltage conversion circuit 46 outputs the temperature compensation voltage using a Class A amplifier circuit AM, the temperature compensation voltage VCP for proper temperature compensation of the oscillation frequency over a wide temperature range can be output by a Class A amplifier circuit AM with a small circuit size and simple configuration.

[0094] Figure 21 shows an example configuration of a Class A amplifier circuit AM. The amplifier circuit AM includes a differential section DP and an output section QP. The differential section DP includes transistors TD1 and TD2 that constitute a current mirror circuit, bipolar transistors BP1 and BP2 which are differential pair transistors, and a bipolar transistor BP3 for the current source. Transistors TD1 and TD2 are P-type transistors with a common gate connection. The inverting input terminal, which is the base of bipolar transistor BP1, is input to the voltage VCP0 from the current generation circuit 43, and the non-inverting input terminal, which is the base of bipolar transistor BP2, is input to the reference voltage VRC. The output section QP includes a P-type drive transistor TD3 and a bipolar transistor BP4 for the current source, which are provided in series between the VDD node and the GND node. The amplifier circuit AM is also provided with a resistor RD and a capacitor CD for phase compensation. Note that MOS transistors may be used instead of bipolar transistors BP1 to BP4.

[0095] On the other hand, Figure 22 shows an example configuration of a Class AB amplifier circuit AM. The difference from Figure 21 is that in Figure 22, the output section QP includes a P-type drive transistor TD4 and an N-type drive transistor TD5, which are connected in series between the VDD node and the GND node. Also in Figure 22, a switch circuit SW and a bipolar transistor BP5 are provided to control the gate of the drive transistor TD5.

[0096] In this embodiment, in order to temperature compensate for the frequency-temperature characteristics of the oscillator 10 shown in Figure 17, a first variable capacitance circuit 31 with a positive voltage-capacitance characteristic is used in the first mode. Therefore, the temperature compensation circuit 40 outputs a temperature compensation voltage VCP with a temperature characteristic as shown in Figure 19. In this case, as shown in A3 of Figure 19, the amplification circuit AM of the temperature compensation circuit 40 needs to output a sufficiently high voltage at the upper limit of the operating temperature range. Even when using the Class A amplification circuit AM shown in Figure 21 as the output amplifier of the temperature compensation circuit 40, the P-type drive transistor TD3 of the output section QP is sufficiently turned on, making it possible to easily output a high voltage as shown in A3 of Figure 19. Therefore, it becomes unnecessary to use the Class AB amplification circuit AM shown in Figure 22, which allows for circuit simplification and miniaturization.

[0097] 5. Frequency control circuit Next, the frequency control circuit 50 will be described in detail. Figure 23 shows an example configuration of the frequency control circuit 50. Note that the frequency control circuit 50 is not limited to the configuration shown in Figure 23, and various modifications can be made, such as omitting some of these components, adding other components, or replacing some components with other components.

[0098] The frequency control circuit 50 of this embodiment outputs a voltage generated by dividing an externally input control voltage VC with at least one variable resistor as the frequency control voltage VFC. For example, the frequency control circuit 50 generates the frequency control voltage VFC by dividing the control voltage VC with a variable resistor without using an amplifier composed of an operational amplifier or the like. For example, if an amplifier is used for gain adjustment in the frequency control circuit 50, the circuit size increases, power consumption increases, and noise also increases with the increase in transistors. In this respect, the frequency control circuit 50 in Figure 23 outputs a voltage generated by dividing the control voltage VC with a variable resistor as the frequency control voltage VFC. In this way, it is possible to control the oscillation frequency by the frequency control voltage VFC without using an amplifier which has a large circuit size and high power consumption and noise, thus enabling miniaturization of the circuit device 20, low power consumption, and low noise.

[0099] In particular, in this embodiment, in the fifth mode, such as the inverting VCXO mode shown in Figure 6, the switch circuit 36 ​​outputs a frequency control voltage VFC to the first output terminal TQ1 and a fixed voltage to the second output terminal TQ2. Therefore, the frequency control voltage VFC is output as the first output voltage VQ1 to the first variable capacitance circuit 31 with positive characteristics. This makes it possible to perform frequency control using the frequency control voltage VFC with characteristics opposite to those of a normal VCXO, and to realize an inverting VCXO that performs inverting frequency control. In this inverting VCXO, when the frequency control voltage VFC increases, the capacitance of the first variable capacitance circuit 31 with positive characteristics to which the frequency control voltage VFC is input increases, and the oscillation frequency decreases. When the frequency control voltage VFC decreases, the capacitance of the first variable capacitance circuit 31 decreases, and the oscillation frequency increases. Therefore, even when a frequency control circuit 50 without an amplifier such as an inverting amplifier is used, as shown in Figure 23, an inverting VCXO can be realized in which the oscillation frequency decreases when the frequency control voltage VFC increases and increases when the frequency control voltage VFC decreases.

[0100] Specifically, the frequency control circuit 50 in Figure 23 includes a first variable resistor RA1, a second variable resistor RA2, a third variable resistor RA3, and a fourth variable resistor RA4. The first variable resistor RA1 is provided between the input node NA1 of the control voltage VC and the output node NA2 of the frequency control voltage VFC. One end of the second variable resistor RA2 is connected to the output node NA2 of the frequency control voltage VFC. The third variable resistor RA3 is provided between the input node NA3 of the reference voltage VREG and the connection node NA4 to which the other end of the second variable resistor RA2 is connected. The fourth variable resistor RA4 is provided between the connection node NA4 and the low-potential power supply node NA5. The low-potential power supply node NA5 is, for example, a GND node.

[0101] In the frequency control circuit 50 shown in Figure 23, the currents IA1, IA2, IA3, and IA4 flowing through the first variable resistor RA1, the second variable resistor RA2, the third variable resistor RA3, and the fourth variable resistor RA4 can be calculated using the following equations (1), (2), and (3).

[0102]

number

[0103] As a result, the voltage VM at the connected node NA4, which is the voltage divider node for the third variable resistor RA3 and the fourth variable resistor RA4, can be calculated as shown in equations (4) and (5) below.

[0104]

number

[0105] Therefore, the frequency control voltage VFC can be calculated as shown in equations (6) and (7) below.

[0106]

number

[0107] The gain G = ΔVFC / ΔVC in the frequency control circuit 50 is expressed as shown in equation (8) below.

[0108]

number

[0109] As shown in equation (8) above, the frequency control circuit 50 of this embodiment makes it possible to adjust the gain G of the frequency control voltage VFC with respect to the control voltage VC using a small circuit configuration without using an amplifier. For example, the gain G in the frequency control circuit 50 can be adjusted by adjusting the resistance values ​​of the first variable resistor RA1 to the fourth variable resistor RA4. Therefore, it becomes possible to adjust the gain G of the frequency control voltage VFC with respect to the control voltage VC to any value without using an amplifier, which has a large circuit size and consumes a lot of power and noise.

[0110] 6. Oscillator Figure 24 shows a first structural example of the oscillator 4 of this embodiment. The oscillator 4 has a resonator 10, a circuit device 20, and a package 15 that houses the resonator 10 and the circuit device 20. The package 15 is made of, for example, ceramic, and has a housing space inside, in which the resonator 10 and the circuit device 20 are housed. The housing space is hermetically sealed and preferably in a reduced-pressure state, close to a vacuum. The package 15 can suitably protect the resonator 10 and the circuit device 20 from shock, dust, heat, moisture, etc.

[0111] Package 15 has a base 16 and a lid 17. Specifically, package 15 consists of a base 16 that supports the resonator 10 and the circuit device 20, and a lid 17 that is joined to the upper surface of the base 16 to form a housing space between it and the base 16. The resonator 10 is supported by terminal electrodes on a stepped portion provided on the inside of the base 16. The circuit device 20 is located on the inner bottom surface of the base 16. Specifically, the circuit device 20 is positioned so that its active surface faces the inner bottom surface of the base 16. The active surface is the surface on which the circuit elements of the circuit device 20 are formed. Bumps BMP are formed on the terminals of the circuit device 20. The circuit device 20 is supported on the inner bottom surface of the base 16 via conductive bumps BMP. The conductive bumps BMP are, for example, metal bumps, and the resonator 10 and the circuit device 20 are electrically connected via these bumps BMP, the internal wiring of package 15, and terminal electrodes. The circuit device 20 is also electrically connected to the external terminals 18 and 19 of the oscillator 4 via the bump BMP and the internal wiring of the package 15. The external terminals 18 and 19 are formed on the outer bottom surface of the package 15. The external terminals 18 and 19 are connected to an external device via external wiring. The external wiring is, for example, wiring formed on the circuit board on which the external device is mounted. This allows the output of a clock signal and the like to the external device.

[0112] In Figure 24, the circuit device 20 is flip-mounted so that its active surface faces downwards, but this embodiment is not limited to this mounting. For example, the circuit device 20 may be mounted so that its active surface faces upwards. That is, the circuit device 20 may be mounted so that its active surface faces the oscillator 10.

[0113] Figure 25 shows a second structural example of the oscillator 4. The oscillator 4 has a resonator 10, a circuit device 20, and a package 15 that houses the resonator 10 and the circuit device 20. The package 15 has a base 16 and a lid 17. The base 16 has a first substrate 6 which is an intermediate substrate, a second substrate 7 which is a roughly rectangular frame shape and is laminated on the upper side of the first substrate 6, and a third substrate 8 which is a roughly rectangular frame shape and is laminated on the bottom side of the first substrate 6. The lid 17 is bonded to the upper surface of the second substrate 7, and the resonator 10 is housed in a housing space S1 formed by the first substrate 6, the second substrate 7 and the lid 17. For example, the resonator 10 is hermetically sealed in the housing space S1, and preferably in a reduced pressure state that is close to a vacuum. This allows the resonator 10 to be suitably protected from shock, dust, heat, moisture, etc. The circuit device 20, which is a semiconductor chip, is housed in a housing space S2 formed by the first substrate and the third substrate 8. Furthermore, external terminals 18 and 19, which are electrode terminals for external connection of the oscillator 4, are formed on the bottom surface of the third substrate 8.

[0114] In the housing space S1, the vibrator 10 is connected to a first electrode terminal and a second electrode terminal (not shown) formed on the upper surface of the first substrate 6 by conductive connectors CDC1 and CDC2. The conductive connectors CDC1 and CDC2 may be realized by conductive bumps such as metal bumps, or by conductive adhesive. Specifically, for example, a first electrode pad (not shown) formed at one end of a tuning fork-type vibrator 10 is connected to a first electrode terminal formed on the upper surface of the first substrate 6 via the conductive connector CDC1. The first electrode terminal is then electrically connected to pad PX1 of the circuit device 20. A second electrode pad (not shown) formed at the other end of the tuning fork-type vibrator 10 is connected to a second electrode terminal formed on the upper surface of the first substrate 6 via the conductive connector CDC2. The second electrode terminal is then electrically connected to pad PX2 of the circuit device 20. This allows one end and the other end of the vibrator 10 to be electrically connected to pads PX1 and PX2 of the circuit device 20 via the conductive connectors CDC1 and CDC2. Furthermore, conductive bump BMPs are formed on multiple pads of the semiconductor chip circuit device 20, and these conductive bump BMPs are connected to multiple electrode terminals formed on the bottom surface of the first substrate 6. The electrode terminals connected to the pads of the circuit device 20 are then electrically connected to the external terminals 18 and 19 of the oscillator 4 via internal wiring, etc.

[0115] The oscillator 4 may also be a wafer-level package (WLP) oscillator. In this case, the oscillator 4 includes a semiconductor substrate, a base having through-electrodes penetrating between the first and second surfaces of the semiconductor substrate, a resonator 10 fixed to the first surface of the semiconductor substrate via a conductive bonding member such as a metal bump, and external terminals provided on the second surface side of the semiconductor substrate via an insulating layer such as a redistribution wiring layer. An integrated circuit forming the circuit device 20 is then formed on the first or second surface of the semiconductor substrate. In this case, the multiple bases and multiple lids are joined by attaching a first semiconductor wafer, on which multiple bases with the resonator 10 and integrated circuit are formed, to a second semiconductor wafer, on which multiple lids are formed, and then the oscillator 4 is diced using a dicing saw or the like. In this way, a wafer-level package oscillator 4 can be realized, enabling high-throughput and low-cost manufacturing of the oscillator 4.

[0116] As described above, the circuit device of this embodiment includes a first variable capacitance circuit in which the capacitance change characteristic with respect to the capacitance control voltage is positive, and a second variable capacitance circuit in which the capacitance change characteristic with respect to the capacitance control voltage is negative, and includes an oscillator circuit that causes an oscillator to oscillate. The circuit device also includes a switch circuit in which a first input voltage is input to a first input terminal, a second input voltage is input to a second input terminal, a first output voltage selected from a plurality of voltages including the first input voltage and the second input voltage is output to a first output terminal to which the first variable capacitance circuit is electrically connected, and a second output voltage selected from a plurality of voltages is output to a second output terminal to which the second variable capacitance circuit is electrically connected.

[0117] According to this embodiment, a voltage selected from a plurality of voltages, including a first input voltage and a second input voltage, can be output as a first output voltage and a second output voltage to a first variable capacitance circuit and a second variable capacitance circuit, respectively. The first output voltage can then be input as a capacitance control voltage to the first variable capacitance circuit with a positive voltage-capacitance characteristic to adjust or set the oscillation frequency of the oscillation circuit, or the second output voltage can be input as a capacitance control voltage to the second variable capacitance circuit with a negative voltage-capacitance characteristic to adjust or set the oscillation frequency of the oscillation circuit. This makes it possible to provide a circuit device that can realize various operating modes using a first variable capacitance circuit and a second variable capacitance circuit with different voltage-capacitance polarities.

[0118] Furthermore, in this embodiment, a temperature compensation circuit is included that outputs a temperature compensation voltage to temperature-compensate the oscillation frequency of the oscillation circuit, and the first input voltage may be the temperature compensation voltage.

[0119] In this way, the switch circuit receives the temperature compensation voltage from the temperature compensation circuit as the first input voltage at the first input terminal, and this temperature compensation voltage can be output as the first output voltage to the first variable capacitor circuit with positive characteristics, or as the second output voltage to the second variable capacitor circuit with negative characteristics.

[0120] Furthermore, in this embodiment, a frequency control circuit is included that outputs a frequency control voltage for the oscillation frequency of the oscillation circuit, and the second input voltage may be the frequency control voltage.

[0121] In this way, the switch circuit receives the frequency control voltage from the frequency control circuit as the second input voltage at the second input terminal, and this frequency control voltage can be output as the second output voltage to a second variable capacitor circuit with negative characteristics, or as the first output voltage to a first variable capacitor circuit with positive characteristics.

[0122] In this embodiment, the multiple voltages may include a fixed voltage, and the switch circuit may output the fixed voltage to the first output terminal or the second output terminal.

[0123] By configuring the switch circuit to output a fixed voltage to either the first or second output terminal, the capacitance of either the first or second variable capacitance circuit can be set to a fixed capacitance.

[0124] In this embodiment, the switch circuit may output a fixed voltage, either a fixed voltage on the high-potential side or a fixed voltage on the low-potential side, to the first output terminal or the second output terminal.

[0125] In this way, it becomes possible to fix the capacitance of the first variable capacitance circuit and the second variable capacitance circuit to a high capacitance or a low capacitance.

[0126] In this embodiment, the switch circuit may output a temperature compensation voltage that compensates the oscillation frequency of the oscillation circuit based on the temperature detection result of the temperature sensor, and a frequency control circuit that outputs a frequency control voltage for the oscillation frequency. In the first mode, the switch circuit may output a temperature compensation voltage to the first output terminal and a frequency control voltage to the second output terminal.

[0127] In this way, the temperature compensation voltage from the temperature compensation circuit is supplied to the first variable capacitor circuit with positive characteristics, and the frequency control voltage from the frequency control voltage is supplied to the second variable capacitor circuit with negative characteristics, thereby realizing an operating mode that enables both temperature compensation by the temperature compensation voltage and frequency control by the frequency control voltage.

[0128] In this embodiment, the switch circuit may output a temperature-compensated voltage to the first output terminal and a first fixed voltage to the second output terminal in the second mode.

[0129] In this way, the temperature compensation voltage from the temperature compensation circuit is supplied to the first variable capacitance circuit with positive characteristics, and the first fixed voltage is supplied to the second variable capacitance circuit as a capacitance control voltage, thereby realizing an operating mode in which temperature compensation is performed by the temperature compensation voltage.

[0130] In this embodiment, the switch circuit may output a second fixed voltage to the first output terminal and a frequency control voltage to the second output terminal in the third mode.

[0131] In this way, the frequency control voltage from the frequency control circuit is supplied to the second variable capacitor circuit with negative characteristics, and the second fixed voltage is supplied to the first variable capacitor circuit as the capacitance control voltage, thereby realizing an operating mode in which frequency control is performed by the frequency control voltage.

[0132] In this embodiment, the switch circuit may output a third fixed voltage to the first output terminal and a fourth fixed voltage to the second output terminal in the fourth mode.

[0133] In this way, the third fixed voltage is supplied to the first variable capacitance circuit as a capacitance control voltage, and the fourth fixed voltage is supplied to the second variable capacitance circuit as a capacitance control voltage, thereby realizing an operating mode in which neither temperature compensation by the temperature compensation voltage nor frequency control by the frequency control voltage is performed.

[0134] In this embodiment, the switch circuit may output a frequency control voltage to the first output terminal and a fifth fixed voltage or temperature compensation voltage to the second output terminal in the fifth mode.

[0135] In this way, the frequency control voltage from the frequency control voltage is supplied to the first variable capacitor circuit with positive characteristics, and the fifth fixed voltage or temperature compensation voltage is supplied to the second variable capacitor circuit with negative characteristics, thereby realizing an operating mode in which the oscillation frequency decreases when the frequency control voltage increases and increases when the frequency control voltage decreases.

[0136] Furthermore, this embodiment may include a non-volatile memory for storing setting information for the voltage selection of the switch circuit.

[0137] In this way, based on the voltage selection setting information stored in non-volatile memory that can retain information even without a power supply, the voltage selected by the switch circuit can be output as the first output voltage from the first output terminal or as the second output voltage from the second output terminal.

[0138] Furthermore, the circuit device of this embodiment includes a first variable capacitance circuit in which the capacitance change characteristic with respect to the capacitance control voltage is positive, and a second variable capacitance circuit in which the capacitance change characteristic with respect to the capacitance control voltage is negative, an oscillator circuit that causes an oscillator to oscillate, and a frequency control circuit that outputs a frequency control voltage of the oscillation frequency of the oscillator circuit.In the circuit device of this embodiment, in the first mode, the frequency control voltage is input to the second variable capacitance circuit as the capacitance control voltage, and in the second mode, the frequency control voltage is input to the first variable capacitance circuit as the capacitance control voltage.

[0139] In this way, when the circuit device is set to the first mode, an operating mode can be achieved in which the oscillation frequency increases when the frequency control voltage increases and decreases when the frequency control voltage decreases. Furthermore, when the circuit device is set to the second mode, an operating mode can be achieved in which the oscillation frequency decreases when the frequency control voltage increases and increases when the frequency control voltage decreases.

[0140] The oscillator of this embodiment also includes a resonator and a circuit device. The circuit device includes a first variable capacitance circuit in which the capacitance change characteristic with respect to the capacitance control voltage is positive, and a second variable capacitance circuit in which the capacitance change characteristic with respect to the capacitance control voltage is negative, and includes an oscillation circuit that causes the resonator to oscillate. The circuit device also includes a switch circuit in which a first input voltage is input to a first input terminal, a second input voltage is input to a second input terminal, a first output voltage selected from a plurality of voltages including the first input voltage and the second input voltage is output to a first output terminal to which the first variable capacitance circuit is connected, and a second output voltage selected from a plurality of voltages is output to a second output terminal to which the second variable capacitance circuit is connected.

[0141] Furthermore, the oscillator of this embodiment includes a resonator and a circuit device. The circuit device includes a first variable capacitance circuit in which the capacitance change characteristic with respect to the capacitance control voltage is positive, and a second variable capacitance circuit in which the capacitance change characteristic with respect to the capacitance control voltage is negative, an oscillation circuit that causes the resonator to oscillate, and a frequency control circuit that outputs a frequency control voltage of the oscillation frequency of the oscillation circuit. In the oscillator of this embodiment, in the first mode, the frequency control voltage is input to the second variable capacitance circuit as the capacitance control voltage, and in the second mode, the frequency control voltage is input to the first variable capacitance circuit as the capacitance control voltage.

[0142] Although this embodiment has been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novelty and effects of this disclosure. Therefore, all such modifications are included within the scope of this disclosure. For example, any term that appears at least once in the specification or drawings together with a broader or synonymous term may be replaced with that different term anywhere in the specification or drawings. Furthermore, all combinations of this embodiment and its modifications are also included within the scope of this disclosure. In addition, the configuration and operation of the circuit device, oscillator, etc., are not limited to those described in this embodiment, and various modifications are possible. [Explanation of Symbols]

[0143] 4...Oscillator, 6...First board, 7...Second board, 8...Third board, 10...Resonator, 15...Package, 16...Base, 17...Lid, 18...External terminal, 19...External terminal, 20...Circuit device, 30...Oscillator circuit, 31...First variable capacitor circuit, 32...Second variable capacitor circuit, 34...Reference voltage generation circuit, 36...Switch circuit, 40...Temperature compensation circuit, 42...Current generation circuit, 43...First-order correction circuit, 44...Higher-order correction circuit, 46...Current-voltage conversion circuit, 48...Temperature sensor, 50...Frequency control circuit, 60...Logic circuit, 70...Non-volatile memory, 80...Output circuit, 90...Power supply circuit, AM...Amplifier circuit, BP1~BP5...Bipolar transistor, CB1~CB6, CC, CD...Capacitor, CK...Clock signal, DP...Differential section, DV...Drive circuit, IA1~IA4...Current, PCK, PGND, PVC, PVDD, PX1, PX2…Pads, QP…Output section, RA, RC, RD…Resistors, RA1~RA4…1st variable resistor~4th variable resistor, S1, S2…Housing space, TD1, TD2, TR1, TR2…Transistors, TD3, TD4, TD5…Drive transistors, TVDD, TGND, TVC, TCK…Terminals, VC…Control voltage, VCC…Capacitance control voltage, VCP…Temperature compensation voltage, VFC…Frequency control voltage, VTS…Temperature detection voltage, TI1…1st input terminal, TI2…2nd input terminal, TI2…3rd input terminal, TQ1…1st output terminal, TQ2…2nd output terminal, TQ3…3rd output terminal, VI1…1st input voltage, VI2…2nd input voltage, VI3…3rd input voltage, VQ1…1st output voltage, VQ2…2nd output voltage, VQ3…3rd output voltage

Claims

1. A circuit device used in an oscillator having a resonator, An oscillator circuit comprising: a first variable capacitance circuit electrically connected to the oscillator and having a positive capacitance change characteristic with respect to a first capacitance control voltage; and a second variable capacitance circuit electrically connected to the oscillator and having a negative capacitance change characteristic with respect to a second capacitance control voltage, wherein the oscillator is made to oscillate, and the oscillation frequency is controlled by variably adjusting the load capacitance by the first and second variable capacitance circuits, A switch circuit that receives a first input voltage at a first input terminal, a second input voltage at a second input terminal, outputs a first output voltage selected from a plurality of voltages including the first input voltage and the second input voltage as the first capacitance control voltage of the first variable capacitor circuit to a first output terminal to which the first variable capacitor circuit is electrically connected, and outputs a second output voltage selected from the plurality of voltages as the second capacitance control voltage of the second variable capacitor circuit to a second output terminal to which the second variable capacitor circuit is electrically connected, A temperature sensor and A temperature compensation circuit outputs a temperature compensation voltage that compensates for the oscillation frequency based on the temperature detection result of the temperature sensor, A frequency control circuit that outputs a frequency control voltage of the oscillation frequency, Includes, The voltage selection of the switch circuit is set by information stored in non-volatile memory, fuse settings by the fuse circuit, or switching of the mask layer, thereby setting the normal operating mode of the oscillator from among multiple operating modes. The aforementioned switch circuit is When the oscillator's normal operating mode is set to the VC-TCXO operating mode, the oscillator is operated as a VC-TCXO by outputting the temperature compensation voltage based on the temperature detection result of the temperature sensor as the first capacitance control voltage of the first variable capacitance circuit to the first output terminal, and the frequency control voltage as the second capacitance control voltage of the second variable capacitance circuit to the second output terminal, thereby performing temperature compensation by the temperature compensation voltage and frequency control by the frequency control voltage. A circuit device characterized in that, when the oscillator's normal operating mode is set to the SPXO operating mode, a third fixed voltage is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit, and a fourth fixed voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit, thereby operating the oscillator as an SPXO without temperature compensation by the temperature compensation voltage or frequency control by the frequency control voltage.

2. In the circuit device according to claim 1, The aforementioned switch circuit is When the oscillator's normal operating mode is set to the TCXO operating mode, the temperature compensation voltage based on the temperature detection result of the temperature sensor is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit, and the first fixed voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit, thereby operating the oscillator as a TCXO in which frequency control by the frequency control voltage is not performed, but temperature compensation by the temperature compensation voltage is performed. A circuit device characterized in that, when the normal operating mode of the oscillator is set to the VCXO operating mode, a second fixed voltage is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit, and the frequency control voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit, thereby operating the oscillator as a VCXO in which temperature compensation is not performed by the temperature compensation voltage but frequency control is performed by the frequency control voltage.

3. In the circuit device according to claim 2, The aforementioned switch circuit is A circuit device characterized by outputting a fixed voltage on the high-potential side or a fixed voltage on the low-potential side as the first fixed voltage and the second fixed voltage.

4. In the circuit device according to any one of claims 1 to 3, The first variable capacitance circuit is, The temperature compensation voltage is supplied to the gate, and the circuit includes multiple transistors to which multiple reference voltages generated by a reference voltage generation circuit are supplied to the source and drain. The second variable capacitance circuit is, A circuit device characterized by including a plurality of transistors to which the frequency control voltage is supplied to the source and drain, and to which a plurality of different reference voltages generated by the reference voltage generation circuit are supplied to the gate.

5. The oscillator and, Circuit equipment and, Includes, The aforementioned circuit device is An oscillator circuit comprising: a first variable capacitance circuit electrically connected to the oscillator and having a positive capacitance change characteristic with respect to a first capacitance control voltage; and a second variable capacitance circuit electrically connected to the oscillator and having a negative capacitance change characteristic with respect to a second capacitance control voltage, wherein the oscillator is made to oscillate, and the oscillation frequency is controlled by variably adjusting the load capacitance by the first and second variable capacitance circuits, A switch circuit that receives a first input voltage at a first input terminal, a second input voltage at a second input terminal, outputs a first output voltage selected from a plurality of voltages including the first input voltage and the second input voltage as the first capacitance control voltage of the first variable capacitor circuit to a first output terminal to which the first variable capacitor circuit is electrically connected, and outputs a second output voltage selected from the plurality of voltages as the second capacitance control voltage of the second variable capacitor circuit to a second output terminal to which the second variable capacitor circuit is electrically connected, A temperature sensor and A temperature compensation circuit outputs a temperature compensation voltage that compensates for the oscillation frequency based on the temperature detection result of the temperature sensor, A frequency control circuit that outputs a frequency control voltage of the oscillation frequency, Includes, The voltage selection of the switch circuit is set by information stored in non-volatile memory, fuse settings by the fuse circuit, or switching of the mask layer, thereby setting the normal operating mode of the oscillator from among multiple operating modes. The aforementioned switch circuit is When the oscillator's normal operating mode is set to the VC-TCXO operating mode, the oscillator is operated as a VC-TCXO by outputting the temperature compensation voltage based on the temperature detection result of the temperature sensor as the first capacitance control voltage of the first variable capacitance circuit to the first output terminal, and the frequency control voltage as the second capacitance control voltage of the second variable capacitance circuit to the second output terminal, thereby performing temperature compensation by the temperature compensation voltage and frequency control by the frequency control voltage. An oscillator characterized in that, when the oscillator's normal operating mode is set to the SPXO operating mode, a third fixed voltage is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit, and a fourth fixed voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit, thereby operating the oscillator as an SPXO in which neither temperature compensation by the temperature compensation voltage nor frequency control by the frequency control voltage is performed.

6. In the oscillator according to claim 5, The aforementioned switch circuit is When the oscillator's normal operating mode is set to the TCXO operating mode, the temperature compensation voltage based on the temperature detection result of the temperature sensor is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit, and the first fixed voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit, thereby operating the oscillator as a TCXO in which frequency control by the frequency control voltage is not performed, but temperature compensation by the temperature compensation voltage is performed. An oscillator characterized in that, when the normal operating mode of the oscillator is set to the VCXO operating mode, a second fixed voltage is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit, and the frequency control voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit, thereby operating the oscillator as a VCXO in which temperature compensation is not performed by the temperature compensation voltage but frequency control is performed by the frequency control voltage.

7. In the oscillator according to claim 6, The aforementioned switch circuit is An oscillator characterized by outputting a fixed voltage on the high-potential side or a fixed voltage on the low-potential side as the first fixed voltage and the second fixed voltage.

8. In the oscillator according to any one of claims 5 to 7, The first variable capacitance circuit is, The temperature compensation voltage is supplied to the gate, and the circuit includes multiple transistors to which multiple reference voltages generated by a reference voltage generation circuit are supplied to the source and drain. The second variable capacitance circuit is, An oscillator characterized by including a plurality of transistors to which the frequency control voltage is supplied to the source and drain, and to which a plurality of different reference voltages generated by the reference voltage generation circuit are supplied to the gate.

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