Circuit device and oscillator

Abstract

A circuit arrangement and an oscillator. The present invention achieves temperature compensation in which the influence of fluctuation in a power supply voltage and offset adjustment are appropriately reflected. A circuit device (20) that operates by being supplied with a power supply voltage (VDD) includes: an oscillation circuit (30) that oscillates an oscillator (10); a temperature sensor (50) that outputs a temperature detection voltage (VTS); an offset adjustment circuit (60) that outputs an offset adjustment voltage (VOF) of the temperature detection voltage (VTS); a correction voltage output circuit (70) to which the power supply voltage (VDD) and the offset adjustment voltage (VOF) are input, and which outputs a correction voltage (VCR) that varies in accordance with the power supply voltage (VDD) and the offset adjustment voltage (VOF); a correction circuit (74) to which the temperature detection voltage (VTS) and the correction voltage (VCR) are input, and which outputs a corrected temperature detection voltage (VTS2) on the basis of the correction voltage (VCR); and a temperature compensation circuit (40) that performs temperature compensation of the oscillation frequency of the oscillation circuit (30) on the basis of the corrected temperature detection voltage (VTS2).

Description

Technical Field

[0001] This invention relates to circuit devices and oscillators, etc. Background Technology

[0002] In circuit devices that oscillate oscillators such as quartz oscillators, temperature compensation of the oscillation frequency is performed. For example, Patent Document 1 discloses an oscillator including a correction circuit that corrects for changes in the temperature compensation voltage caused by variations in the power supply voltage. Furthermore, Patent Document 1 discloses a method that uses a variable resistor in a temperature sensor, and by changing the resistance value of the variable resistor, adjusts the offset of the temperature detection voltage to perform temperature compensation for the zero-order component of the oscillator's frequency-temperature characteristics.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2023-090099

[0004] However, no appropriate temperature compensation circuit was proposed to reflect the effects of power supply voltage variations and offset adjustment. Summary of the Invention

[0005] One aspect of this disclosure relates to a circuit device that operates upon being supplied with a power supply voltage. The circuit device includes: an oscillation circuit that causes an oscillator to oscillate; a temperature sensor that outputs a temperature detection voltage; an offset adjustment circuit that outputs an offset adjustment voltage for the temperature detection voltage; a correction voltage output circuit that receives the power supply voltage and the offset adjustment voltage as inputs and outputs a correction voltage that varies according to the power supply voltage and the offset adjustment voltage; a correction circuit that receives the temperature detection voltage and the correction voltage as inputs and outputs a corrected temperature detection voltage using the correction voltage; and a temperature compensation circuit that performs temperature compensation on the oscillation frequency of the oscillation circuit based on the corrected temperature detection voltage.

[0006] Furthermore, another aspect of this disclosure relates to an oscillator comprising: the circuitry described above; and the oscillator. Attached Figure Description

[0007] Figure 1 This is an example of the structure of the circuit device and oscillator in this embodiment.

[0008] Figure 2 This is a detailed structural example of the circuit device and oscillator in this embodiment.

[0009] Figure 3 This is an example of the frequency-temperature characteristics as the power supply voltage rises.

[0010] Figure 4 This is an example of the frequency-temperature characteristics when the power supply voltage decreases.

[0011] Figure 5 This is an example of the structure of an offset adjustment circuit, a correction voltage output circuit, and a correction circuit.

[0012] Figure 6 This is a detailed structural example of a correction voltage output circuit that allows for variable resistance ratios, etc.

[0013] Figure 7 This is an explanatory diagram of the method for generating the correction voltage corresponding to the power supply voltage.

[0014] Figure 8 This is an example of the temperature characteristics of a temperature sensing voltage.

[0015] Figure 9 This is an explanatory diagram of the correction method in this embodiment.

[0016] Figure 10 This is an example of the structure of a temperature compensation circuit.

[0017] Figure 11 This is the first structural example of a temperature sensor.

[0018] Figure 12 This is the second structural example of a temperature sensor.

[0019] Figure 13 This is a comparative example of the structure of a temperature sensor.

[0020] Figure 14 This is a comparative example of the correction circuit structure.

[0021] Figure 15 This is an explanatory diagram illustrating the change in the slope characteristic of the temperature detection voltage in the comparative example.

[0022] Figure 16 This is an explanatory diagram illustrating the linearity of the offset adjustment voltage in the comparative example.

[0023] Figure 17 This is an explanatory diagram illustrating the linearity of the offset adjustment voltage in this embodiment.

[0024] Figure 18 This is an explanatory diagram about the change in inflection point temperature caused by offset adjustment.

[0025] Figure 19 This is the first construction example of an oscillator.

[0026] Figure 20 This is the second construction example of an oscillator.

[0027] Label Explanation

[0028] 4 Oscillator; 6 First substrate; 7 Second substrate; 8 Third substrate; 10 Vibrator; 15 Package; 16 Base; 17 Cover; 18, 19 External terminals; 20 Circuit assembly; 30 Oscillator circuit; 32 Variable capacitor circuit; 40 Temperature compensation circuit; 42 Current generation circuit; 43 First-order correction circuit; 44 Higher-order correction circuit; 46 Current-to-voltage conversion circuit; 50 Temperature sensor; 52 Correction circuit; 54 Offset generation circuit; 55 Adder circuit; 58 Temperature sensor; 59 Buffer circuit; 60 Offset adjustment circuit; 70 Correction voltage output circuit; 74 Correction Circuit; 80 Output circuit; 90 Power supply circuit; 100 Control circuit; 102 Register; 110 Non-volatile memory; BPE1, BPE2 Bipolar transistors; OPB, OPC, OPD1, OPD2, OPE, OPF1, OPF2 Operational amplifiers; RA1, RA2, RB1, RB2 Resistors; RC1 Resistor; RC1 Resistor; VB Power supply compensation voltage; VC compensation voltage; VCP Temperature compensation voltage; VCR Correction voltage; VDD Power supply voltage; VOF Offset adjustment voltage; VTS, VTS2 Temperature detection voltages. Detailed Implementation

[0029] The following describes this embodiment. Furthermore, the embodiments described below are not intended to unduly limit the scope of the claims. Additionally, the structures described in this embodiment are not necessarily all essential components.

[0030] 1. Circuit device

[0031] Figure 1 An example of the structure of the circuit device 20 of this embodiment is shown. The circuit device 20 of this embodiment includes an oscillation circuit 30, a temperature compensation circuit 40, a temperature sensor 50, an offset adjustment circuit 60, a correction voltage output circuit 70, and a correction circuit 74. Furthermore, the oscillator 4 of this embodiment includes an oscillator 10 and the circuit device 20. The oscillator 10 is electrically connected to the circuit device 20. Additionally, the circuit device 20 and the oscillator 4 are not limited to... Figure 1 The structure can implement various transformations, such as omitting some of the structural elements, adding other structural elements, or replacing some structural elements with other structural elements.

[0032] The oscillator 10 is a component that generates mechanical vibration through an electrical signal. The oscillator 10 can be implemented, for example, using a quartz resonator or similar vibrating plate. For instance, the oscillator 10 can be implemented using a quartz resonator that performs thickness shear vibration with an AT cut or SC cut, a tuning fork type quartz resonator, or a double tuning fork type quartz resonator. For example, the oscillator 10 can be an oscillator built into a temperature-compensated quartz oscillator (TCXO) without a thermostatic bath, or an oscillator built into a thermostatic bath type quartz oscillator (OCXO) with a thermostatic bath. Furthermore, the oscillator 10 of this embodiment can also be implemented using various vibrating plates, such as those other than thickness shear vibration type, tuning fork type, or double tuning fork type, or piezoelectric resonators made of materials other than quartz. For example, the oscillator 10 can also be a SAW (Surface Acoustic Wave) resonator or a MEMS (Micro Electro Mechanical Systems) oscillator formed using a silicon substrate as a silicon oscillator.

[0033] Circuit device 20 is an integrated circuit device called an IC (Integrated Circuit). For example, circuit device 20 is an IC manufactured using semiconductor technology, which is a semiconductor chip on a semiconductor substrate with circuit elements formed thereon. Circuit device 20 operates according to the power supply voltage VDD.

[0034] The oscillation circuit 30 is a circuit that causes the oscillator 10 to oscillate. For example, the oscillation circuit 30 generates an oscillation signal by causing the oscillator 10 to oscillate. The oscillation signal is an oscillation clock signal. For example, the oscillation circuit 30 can be implemented using an oscillation drive circuit electrically connected to one end and the other end of the oscillator 10, as well as passive components such as capacitors or resistors. The drive circuit can be implemented, for example, using a CMOS inverter circuit or a bipolar transistor. The drive circuit is the core circuit of the oscillation circuit 30, and it drives the oscillator 10 with voltage or current, thereby causing the oscillator 10 to oscillate. As the oscillation circuit 30, various types of oscillation circuits, such as inverter type, Pierce type, Colpitts type, or Hartley type, can be used. In addition, the connection in this embodiment is an electrical connection. An electrical connection is a connection that can transmit electrical signals, and it is a connection that can transmit information based on electrical signals. The electrical connection can also be a connection via passive components, etc.

[0035] Temperature sensor 50 is a sensor that detects temperature. Specifically, temperature sensor 50 outputs a temperature-dependent voltage, VTS, which varies according to the ambient temperature. For example, temperature sensor 50 uses temperature-dependent circuit elements to generate the temperature detection voltage VTS as a temperature detection signal. Specifically, temperature sensor 50, for example, uses the temperature dependence of the forward voltage of a PN junction to output a temperature detection voltage VTS that varies with temperature. Alternatively, a variation of temperature sensor 50 using a digital temperature sensor circuit can also be implemented. In this case, the temperature detection voltage VTS is generated by performing a D / A conversion on the temperature detection data.

[0036] The offset adjustment circuit 60 outputs an offset adjustment voltage VOF. The offset adjustment voltage VOF is, for example, a voltage used for offset adjustment of the temperature sensing voltage VTS. Offset adjustment can also be called zero-order offset adjustment. For example, the offset adjustment circuit 60 generates the offset adjustment voltage VOF based on zero-order correction data corresponding to the zero-order coefficients of the polynomial in the polynomial approximation of the temperature compensation characteristic. Therefore, the amount of offset of the temperature sensing voltage VTS represented by the zero-order correction data is input to the temperature compensation circuit 40 as the corrected temperature sensing voltage VTS2. This allows adjustment of the offset variation of the temperature sensing voltage VTS caused by manufacturing deviations, etc.

[0037] The correction voltage output circuit 70 outputs a correction voltage VCR. For example, the correction voltage output circuit 70 receives a power supply voltage VDD and an offset adjustment voltage VOF as inputs, and outputs a correction voltage VCR that varies according to the power supply voltage VDD and the offset adjustment voltage VOF. For example, the correction voltage VCR is a voltage that varies with changes in both the power supply voltage VDD and the offset adjustment voltage VOF. For example, the correction voltage VCR is a subtraction or addition operation voltage obtained by multiplying the offset adjustment voltage VOF by a given coefficient and the voltage obtained by multiplying the power supply voltage VDD by a given coefficient. As an example, the correction voltage VCR decreases when the power supply voltage VDD increases and increases when the offset adjustment voltage VOF increases. Thus, the correction voltage output circuit 70 outputs a correction voltage VCR that reflects the voltage changes of both the power supply voltage VDD and the offset adjustment voltage VOF.

[0038] The correction circuit 74 outputs a corrected temperature detection voltage VTS2. For example, the correction circuit 74 receives a temperature detection voltage VTS and a correction voltage VCR as inputs, and outputs a corrected temperature detection voltage VTS2 based on the correction voltage VCR. The corrected temperature detection voltage VTS2 is, for example, a voltage that causes a change in the temperature detection voltage VTS corresponding to the correction voltage VCR. For example, the corrected temperature detection voltage VTS2 is a subtraction or addition of the voltage obtained by multiplying the temperature detection voltage VTS by a given coefficient and the voltage obtained by multiplying the correction voltage VCR by a given coefficient. As an example, the corrected temperature detection voltage VTS2 increases when the temperature detection voltage VTS increases and decreases when the correction voltage VCR increases. Thus, the correction circuit 74 outputs a temperature detection voltage VTS2 corrected by the correction voltage VCR calculated based on the power supply voltage VDD and the offset adjustment voltage VOF. Therefore, for the temperature detection voltage VTS from the temperature sensor 50, a temperature detection voltage VTS2 reflecting changes in the power supply voltage VDD and the offset adjustment voltage VOF is generated. Alternatively, the following variation can be implemented: the correction circuit 74 corrects the temperature detection voltage VTS from the temperature sensor 50 located outside the circuit device 20 and outputs the temperature detection voltage VTS2.

[0039] The temperature compensation circuit 40 performs temperature compensation for the oscillation frequency of the oscillation circuit 30. Temperature compensation, for example, is a process that compensates for fluctuations in the oscillation frequency caused by temperature variations. 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 in the presence of temperature variations. Furthermore, in this embodiment, the temperature compensation circuit 40 performs temperature compensation for the oscillation frequency of the oscillation circuit 30 based on the corrected temperature detection voltage VTS2. For example, the temperature compensation circuit 40 outputs a temperature compensation voltage VCP based on the temperature detection voltage VTS2 to perform temperature compensation for the oscillation frequency. Thus, the temperature compensation circuit 40 performs temperature compensation for the oscillation frequency of the oscillation circuit 30 based on the temperature detection voltage VTS2 obtained by correcting the temperature detection voltage VTS of the temperature sensor 50 using a correction voltage VCR calculated based on the power supply voltage VDD and the offset adjustment voltage VOF. Additionally, a variation can be implemented where the temperature compensation data obtained by A / D conversion of the temperature compensation voltage VCP is used to digitally adjust the oscillation frequency in the variable capacitor circuit of the oscillation circuit 30.

[0040] For example, when the power supply voltage VDD rises, the heat generated by the circuit device 20, which operates based on the power supply voltage VDD, increases, and the detected temperature of the temperature sensor 50 rises. However, the circuit device 20 and the oscillator 10 are physically separated, so the detected temperature in the circuit device 20 is inconsistent with the temperature of the oscillator 10; for example, the temperature of the oscillator 10 is lower. Therefore, when the temperature compensation circuit 40 outputs a temperature compensation voltage VCP based on the temperature detection voltage VTS of the temperature sensor 50 of the circuit device 20 and performs temperature compensation for the oscillation frequency of the oscillator 10 using this temperature compensation voltage VCP, an inaccurate temperature compensation cannot be achieved.

[0041] Furthermore, in temperature compensation of the oscillation frequency, zero-order offset adjustment is required. This zero-order offset adjustment can be achieved, for example, by adjusting the offset of the temperature sensing voltage VTS. In this regard, in the prior art of Patent Document 1 mentioned above, a variable resistor is provided in the temperature sensor 50, and the offset adjustment of the temperature sensing voltage VTS is performed within the temperature sensor 50 by adjusting the resistance value of the variable resistor. However, in this prior art method, as will be described in detail later, problems have been identified such as linear degradation of the offset adjustment or changes in the slope characteristic of the temperature sensing voltage VTS relative to temperature due to the offset adjustment.

[0042] Therefore, in this embodiment, the temperature sensor 50 does not have an offset adjustment function for the temperature detection voltage VTS, and an offset adjustment circuit 60 for outputting an offset adjustment voltage VOF is provided separately from the temperature sensor 50. Furthermore, the correction voltage output circuit 70 outputs a correction voltage VCR that varies according to the power supply voltage VDD and the offset adjustment voltage VOF, and the correction circuit 74 outputs a temperature detection voltage VTS2 after correcting the temperature detection voltage VTS of the temperature sensor 50 using the correction voltage VCR. Then, the temperature compensation circuit 40 performs temperature compensation of the oscillation frequency of the oscillation circuit 30 based on the corrected temperature detection voltage VTS2 from the correction circuit 74. For example, the capacitance of the variable capacitor circuit provided in the oscillation circuit 30 is adjusted based on the temperature compensation voltage VCP from the temperature compensation circuit 40, thereby performing temperature compensation of the oscillation frequency.

[0043] Thus, due to the variation of the power supply voltage VDD, the temperature difference between the detected temperature in the circuit device 20 and the temperature of the oscillator 10 increases. Even in the case of temperature compensation causing error, by correcting to reduce this error, the accuracy of the oscillation frequency can be improved.

[0044] Furthermore, in this embodiment, an offset adjustment circuit 60 is provided separately from the temperature sensor 50 to generate an offset adjustment voltage VOF. The temperature detection voltage VTS of the temperature sensor 50 is corrected using a correction voltage VCR generated by the power supply voltage VDD and the offset adjustment voltage VOF, and temperature compensation is performed using the corrected temperature detection voltage VTS2. Therefore, the problem of linear degradation of the offset adjustment caused by giving the temperature sensor 50 an offset adjustment function, and the problem of the slope characteristic of the temperature detection voltage VTS changing due to the offset adjustment, can be suppressed. In addition, by performing temperature compensation based on the temperature detection voltage VTS corrected using the correction voltage VCR based on the power supply voltage VDD and the offset adjustment voltage VOF, corrections in higher-order circuits of the temperature compensation circuit 40 can also be performed, enabling appropriate temperature compensation of the oscillation frequency.

[0045] Figure 2 A detailed structural example of the circuit device 20 and oscillator 4 in this embodiment is shown. Figure 2 In addition to the oscillation circuit 30, temperature compensation circuit 40, temperature sensor 50, offset adjustment circuit 60, correction voltage output circuit 70, and correction circuit 74, the circuit device 20 also includes an output circuit 80, a power supply circuit 90, a control circuit 100, and a non-volatile memory 110. Furthermore, the oscillator 4 includes a vibrator 10 and the circuit device 20, with the vibrator 10 electrically connected to the circuit device 20. For example, the vibrator 10 and the circuit device 20 can be electrically connected using internal wiring, bonding wires, or metal bumps within a package housing the vibrator 10 and the circuit device 20. Moreover, the circuit device 20 and the oscillator 4 are not limited to... Figure 2 The structure can implement various transformations, such as omitting some of the structural elements, adding other structural elements, or replacing some structural elements with other structural elements.

[0046] Furthermore, the circuit device 20 includes pads PVDD, PGND, PX1, PX2, and PCK. The pads are terminals of the circuit device 20, which serves as a semiconductor chip. For example, in the pad region, a metal layer is exposed from a passivation film that serves as an insulating layer, and this exposed metal layer constitutes the pads that are terminals of the circuit device 20. Pads PVDD and PGND are power pads and ground pads, respectively. The power supply voltage VDD from an external power supply device is supplied to pad PVDD. Pad PGND is the pad supplied with GND as the ground voltage. GND can also be referred to as VSS, and the ground voltage is, for example, the ground potential. In this embodiment, ground is appropriately referred to as GND. 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 PCK is the pad for outputting the clock signal CK. Pads PVDD, PGND, and PCK are electrically connected to the external terminals TVDD, TGND, and TCK for external connection of the oscillator 4, respectively. For example, these pads and terminals are electrically connected using internal wiring, bonding wires, or metal bumps within the package. Alternatively, terminals and pads can be provided to receive an external control voltage, which allows an external system to control the oscillation frequency.

[0047] The oscillation circuit 30 is electrically connected to the oscillator 10 via pads PX1 and PX2. Pads PX1 and PX2 are pads for connecting the oscillator. The oscillation drive circuit of the oscillation circuit 30 is disposed between pads PX1 and PX2. The oscillation circuit 30 includes a variable capacitor circuit 32. The variable capacitor circuit 32 is, for example, a circuit that changes the capacitance of at least one of the ends of the oscillator 10. By adjusting the capacitance of the variable capacitor circuit 32, the oscillation frequency of the oscillation circuit 30 can be adjusted. That is, the variable capacitor circuit 32 is electrically connected to at least one of pads PX1 and PX2, thereby allowing the load capacitance of the oscillation circuit 30 to be variably adjusted. The variable capacitor circuit 32 can be implemented, for example, using a variable capacitor element such as a varactor diode. For example, the variable capacitor circuit 32 is composed of at least one variable capacitor element.

[0048] The temperature compensation circuit 40 performs analog temperature compensation, for example, based on polynomial approximation. For instance, when approximating the temperature compensation voltage VCP of the frequency-temperature characteristics of the compensation oscillator 10 using a polynomial, the temperature compensation circuit 40 performs analog temperature compensation based on the coefficient information of the polynomial. Analog temperature compensation is achieved, for example, through addition processing of current or voltage signals, which are analog signals. For example, when approximating the temperature compensation voltage VCP using a high-order polynomial, the 0th, 1st, and high-order coefficients of the polynomial are stored as 0th-order correction data, 1st-order correction data, and high-order correction data, respectively, in a storage unit implemented, for example, a non-volatile memory 110. High-order coefficients are, for example, coefficients larger than the 1st order, and high-order correction data are correction data corresponding to the high-order coefficients. For example, when approximating the temperature compensation voltage VCP using a 3rd-order polynomial, the 0th, 1st, 2nd, and 3rd-order coefficients of the polynomial are stored as 0th-order correction data, 1st-order correction data, 2nd-order correction data, and 3rd-order correction data, respectively, in the storage unit. Then, the temperature compensation circuit 40 performs temperature compensation based on the 0th to 3rd order correction data. In this case, the second-order correction data and temperature compensation based on the second-order correction data can also be omitted. Furthermore, for example, when approximating the temperature compensation voltage VCP using a 5th-order polynomial, the 0th, 1st, 2nd, 3rd, 4th, and 5th order coefficients of the polynomial are stored in the storage unit as 0th-order correction data, 1st-order correction data, 2nd-order correction data, 3rd-order correction data, 4th-order correction data, and 5th-order correction data. Then, the temperature compensation circuit 40 performs temperature compensation based on the 0th to 5th order correction data. In this case, the 2nd or 4th order correction data and temperature compensation based on the 2nd or 4th order correction data can also be omitted. Additionally, the degree of the polynomial approximation is arbitrary; for example, a polynomial approximation with a degree greater than 5 can be performed.

[0049] The control circuit 100 is a circuit that performs various control processes, and is implemented, for example, by logic circuits. For example, the control circuit 100 performs overall control of the circuit device 20, or controls the timing of the operation of the circuit device 20. Furthermore, the control circuit 100 performs various processes for controlling the oscillation circuit 30, or controls the temperature compensation circuit 40, temperature sensor 50, offset adjustment circuit 60, correction voltage output circuit 70, correction circuit 74, output circuit 80, or power supply circuit 90, or controls the reading or writing of information from the non-volatile memory 110. The control circuit 100 can be implemented, for example, by a gate array or other ASIC (Application Specific Integrated Circuit) based on automatic configuration routing. Furthermore, the control circuit 100 includes a register 102. For example, the register 102 is implemented by a storage circuit such as a flip-flop circuit. Moreover, this register 102 stores various information required for temperature compensation and correction processes. For example, the control circuit 100 performs various control processes based on this information read from the non-volatile memory 110 and loaded into the register 102.

[0050] The non-volatile memory 110 is a memory that retains information even when no power is supplied. For example, the non-volatile memory 110 is a memory that can retain information and rewrite information even when no power is supplied. The non-volatile memory 110 stores various information required for the operation of the circuit device 20. The non-volatile memory 110 can be implemented using an EEPROM (Electrically Erasable Programmable Read-Only Memory) implemented using a FAMOS (Floating Gate Avalanche Injection MOS) memory or a MONOS (Metal-Oxide-Nitride-Oxide-Silicon) memory. Furthermore, the non-volatile memory 110 stores correction data such as primary correction data and higher-order correction data used for temperature compensation in the temperature compensation circuit 40.

[0051] The output circuit 80 outputs a clock signal CK based on the oscillation signal from the oscillation circuit 30. For example, the output circuit 80 buffers the oscillation clock signal (oscillation signal) from the oscillation circuit 30 and outputs it as the clock signal CK to the pad PCK. Then, the clock signal CK is output to the outside via the clock output terminal TCK of the oscillator 4. For example, the output circuit 80 outputs the clock signal CK in the form of a single-ended CMOS signal. Alternatively, the output circuit 80 may output the clock signal CK in a signal form other than CMOS. Alternatively, a clock signal generation circuit, such as a PLL circuit that generates a clock signal CK that doubles the frequency of the oscillation signal, may be provided after the oscillation circuit 30, and the output circuit 80 may buffer and output the clock signal CK generated by this clock signal generation circuit.

[0052] The power supply circuit 90 is supplied with a power supply voltage VDD from the pad PVDD and a ground voltage GND from the pad PGND, providing various power supply voltages for the internal circuits of the circuit device 20. For example, the power supply circuit 90 provides an adjusted power supply voltage, after adjusting the power supply voltage VDD, to each circuit of the circuit device 20, such as the oscillation circuit 30.

[0053] The oscillation circuit 30 includes a variable capacitor circuit 32 whose capacitance change characteristic with respect to the capacitor control voltage is, for example, positive. A positive capacitance change characteristic means that the capacitance increases as the capacitor control voltage increases. Alternatively, the capacitance change characteristic of the variable capacitor circuit 32 can also be negative. Furthermore, the temperature compensation circuit 40 provides a temperature compensation voltage VCP as the capacitor control voltage to the variable capacitor circuit 32. Since the variable capacitor circuit 32 is a positive characteristic variable capacitor circuit, its capacitance increases when the temperature compensation voltage VCP from the temperature compensation circuit 40 increases, and decreases when the temperature compensation voltage VCP decreases. By providing a variable capacitor circuit 32 with a positive characteristic, supplied with the temperature compensation voltage VCP from the temperature compensation circuit 40 as the capacitor control voltage, for example, when the temperature rises, the capacitance of the variable capacitor circuit 32 increases, and the oscillation frequency of the oscillation circuit 30 decreases. Thus, for example, in a high-temperature region where the oscillation frequency of the oscillator 10 increases, the capacitance of the variable capacitor circuit 32 increases, thereby achieving temperature compensation to offset the increase in oscillation frequency. Furthermore, by incorporating a variable capacitor circuit 32 with positive characteristics into the oscillation circuit 30, and for example, using an amplifier circuit with Class A operation as the output amplifier for the temperature compensation voltage VCP of the temperature compensation circuit 40, circuit miniaturization can be achieved. Additionally, a variable capacitor circuit that controls the capacitor via an externally input frequency control voltage can be incorporated into the oscillation circuit 30, allowing the oscillation frequency to be variably controlled by this frequency control voltage.

[0054] 2. Offset adjustment circuit, correction voltage output circuit, correction circuit

[0055] In recent years, with the miniaturization of oscillators 4, their heat capacity has decreased, resulting in a larger temperature rise in oscillators 4, even when using the same amount of heat to generate heat in the circuit device 20. Consequently, the temperature difference between the circuit device 20 (the heat source) and the external air temperature increases, as does the temperature difference between the circuit device 20 and the oscillator 10. Therefore, when the temperature difference between the circuit device 20 and the oscillator 10 increases, the difference between the characteristics of the temperature compensation voltage VCP generated based on the temperature detection voltage VTS of the temperature sensor 50 built into the circuit device 20 and the frequency temperature characteristic determined by the temperature of the oscillator 10 increases, leading to a larger error in temperature compensation.

[0056] For example, the frequency-temperature characteristics of the oscillator 4 have individual errors due to manufacturing deviations or installation effects of the circuit device 20 and the oscillator 10, which are ICs. Therefore, adjustments are made through a pre-shipment adjustment process or by adjusting the circuit device 20 to generate an optimal temperature compensation voltage VCP that absorbs these errors. However, countermeasures against the surrounding environment after the product leaves the factory are insufficient. For example, the circuit device 20 operates by being supplied with an external power supply voltage VDD, but the variation of the power supply voltage VDD is, for example, determined to be 3.3V ± 10% in the product specification. Furthermore, when the power supply voltage VDD varies, the heat generated by the circuit device 20, which operates according to the power supply voltage VDD, also varies; when the power supply voltage VDD increases, the heat generated by the circuit device 20 also increases. In this case, with the miniaturization of the package, etc., of the oscillator 4 that mounts the circuit device 20, the temperature rise of the oscillator 4 caused by the heat generated by the circuit device 20 also increases. As a result, as described above, the temperature difference between the circuit device 20 and the oscillator 10 increases, and the temperature compensation error increases.

[0057] For example, Figure 3 This is an example of the frequency-temperature characteristics as the supply voltage VDD rises. Figure 3 In the diagram, the horizontal axis represents temperature T, and the vertical axis represents the frequency f, which is the oscillation frequency. Furthermore, the vertical axis actually represents the frequency deviation relative to the nominal frequency; this frequency deviation will be explained as frequency f below. Figure 3 A1 refers to the frequency-temperature characteristic of the oscillator 10 under typical voltage conditions, such as a power supply voltage VDD of 3.3V. For example, adjustments are made during pre-shipment processing to ensure that the temperature characteristic of the temperature compensation voltage VCP of the circuit device 20 matches the frequency-temperature characteristic of the oscillator 10. Specifically, in Figure 2In the circuit device 20, a variable capacitor circuit 32 with a positive characteristic is used for temperature compensation. Therefore, when the temperature compensation voltage VCP increases, the capacitance of the variable capacitor circuit 32 increases, and the oscillation frequency decreases; when the temperature compensation voltage VCP decreases, the capacitance of the variable capacitor circuit 32 decreases, and the oscillation frequency increases. Thus, by setting the frequency-temperature characteristic of the temperature compensation voltage VCP to... Figure 3 The characteristics shown in A1 can offset the frequency-temperature characteristics of the oscillator 10, thereby achieving temperature compensation that keeps the oscillation frequency constant.

[0058] Figure 3 A2 represents the frequency-temperature characteristic of oscillator 10 when VDD increases by +5%, and A3 represents the frequency-temperature characteristic of oscillator 10 when VDD increases by +10%. For example, due to the heating of circuit device 20 caused by the increase of VDD, the temperature of oscillator 10 also rises. However, if the temperature compensation voltage VCP is adjusted to the frequency-temperature characteristics shown in A2 and A3, appropriate temperature compensation to maintain a constant oscillation frequency can be achieved. Specifically, as described above, in Figure 2 In this circuit, a variable capacitor circuit 32 with positive characteristics is used for temperature compensation. Therefore, when the power supply voltage VDD changes, temperature compensation that keeps the oscillation frequency constant can be achieved by making the frequency-temperature characteristic of the temperature compensation voltage VCP the characteristics shown in A2 and A3.

[0059] However, the circuit device 20 generates a temperature compensation voltage VCP based on the detected temperature of the built-in temperature sensor 50 to perform temperature compensation of the oscillation frequency. Furthermore, as mentioned above, a temperature difference exists between the circuit device 20 and the oscillator 10, such as... Figure 3 When the power supply voltage VDD increases and the heat generated by the circuit device 20 increases, the temperature difference between the temperature detected by the temperature sensor 50 of the circuit device 20 and the temperature of the oscillator 10 increases. Therefore, the circuit device 20... Figure 3 Temperature compensation using the temperature-compensated voltage VCP, as shown in A4 and A5, results in a deviation between the temperature-compensated frequency characteristics (A2 and A3) and the actual temperature of the oscillator 10. Therefore, the temperature-compensated oscillation frequency becomes inaccurate and cannot converge to the specified frequency accuracy.

[0060] on the other hand, Figure 4 This is an example of the frequency-temperature characteristics as the power supply voltage VDD decreases. Figure 4 B1 represents the frequency-temperature characteristic of oscillator 10 under typical voltage conditions such as a power supply voltage VDD of 3.3V. Figure 4B2 represents the frequency-temperature characteristic of the oscillator 10 when VDD decreases by -5%, and B3 represents the frequency-temperature characteristic of the oscillator 10 when VDD decreases by -10%. Thus, even when the power supply voltage VDD decreases, due to the temperature difference between the temperature detected by the temperature sensor 50 of the circuit device 20 and the temperature of the oscillator 10, the circuit device 20 will still... Figure 4 Temperature compensation using the temperature-compensated voltage VCP, as shown in B4 and B5, results in a deviation between the temperature-compensated frequency characteristics (B2 and B3) and those based on the actual temperature of the oscillator 10. Therefore, the temperature-compensated oscillation frequency becomes inaccurate and cannot converge to the specified frequency accuracy.

[0061] In addition, zero offset adjustments are required in temperature compensation. In the aforementioned Patent Document 1, zero offset adjustments were performed in the temperature sensor, but the following problem was identified: linear degradation of the offset adjustment or changes in the slope characteristics of the temperature detection voltage.

[0062] Therefore, in this embodiment, the offset adjustment circuit 60 generates an offset adjustment voltage VOF, the correction voltage output circuit 70 generates a correction voltage VCR based on the offset adjustment voltage VOF and the power supply voltage VDD, the correction circuit 74 corrects the temperature detection voltage VTS based on the correction voltage VCR, and the temperature compensation circuit 40 performs temperature compensation using the corrected temperature detection voltage VTS2. Thus, temperature compensation that appropriately reflects the influence of changes in the power supply voltage VDD and the offset adjustment can be achieved. Figure 5 The diagram shows an example of the structure of the offset adjustment circuit 60, the correction voltage output circuit 70, and the correction circuit 74. However, the structure of the offset adjustment circuit 60, the correction voltage output circuit 70, and the correction circuit 74 is not limited to these examples. Figure 5 Its structure allows for various deformations.

[0063] exist Figure 5In this circuit, an R-2R ladder-structured D / A converter circuit is used as the offset adjustment circuit 60. For example, the offset adjustment circuit 60 is a circuit that converts offset adjustment data from D / A to offset adjustment voltage VOF using an R-2R ladder-structured method. That is, it achieves zero-order offset adjustment using an R-2R ladder-structured method. The offset adjustment data, for example, corresponds to the zero-order correction data for temperature compensation. In the R-2R ladder-structured method, switches SW1 to SWm are used to switch the number of bits of the offset adjustment data between VREG and GND. Then, based on each bit of the offset adjustment data, each switch of SW1 to SWm is switched to either the VREG side or the GND side, thereby switching the resistor value and generating the offset adjustment voltage VOF. Specifically, the offset adjustment circuit 60 includes resistors RA1 and RA2 connected in series between the power supply node and the GND node of VREG, switches SW1 to SWm, a resistor with a resistance value of 2R connected between nodes N1 to Nm and switches SW1 to SWm, and a resistor with a resistance value of R connected between nodes N1 to Nm. Furthermore, based on the m-bit offset adjustment data, switches SW1 to SWm are switched to the VREG side or the GND side. As a result, the voltage after D / A conversion of the offset adjustment data is generated at node N1 as the offset adjustment voltage VOF.

[0064] Thus, the offset adjustment circuit 60 based on the R-2R trapezoidal configuration improves the linearity of the offset adjustment compared to a structure that only provides offset adjustment functionality to a temperature sensor. Furthermore, it prevents the slope characteristics of the temperature detection voltage from changing due to offset adjustment.

[0065] Alternatively, as a variation of the offset adjustment circuit 60, a D / A converter circuit using a series resistor configuration can be used, comprising multiple resistors connected in series between the power supply node and the GND node, and multiple switches connected between the multiple resistor connection nodes and the output node of the offset adjustment voltage VOF. However, in the structure of the D / A converter circuit using the series resistor configuration, there is a problem of increased layout area. In contrast, according to the configuration using... Figure 5 The offset adjustment circuit 60 using an R-2R trapezoidal configuration has the advantage of reducing the resistor layout area by, for example, about 40%, compared to the configuration using series resistors. Furthermore, the offset adjustment circuit 60 is not limited to an R-2R trapezoidal structure; various modifications can be implemented, such as those using series resistors or capacitor distribution configurations for D / A conversion circuits.

[0066] In addition, Figure 5In this circuit, the correction voltage output circuit 70 includes an operational amplifier OPB. A power supply compensation voltage VB, varying according to the power supply voltage VDD, is input to the first input terminal of the operational amplifier OPB. An offset adjustment voltage VOF is input to the second input terminal, and a correction voltage VCR is output from the output terminal. The first input terminal is, for example, an inverting input terminal of the operational amplifier OPB, and the second input terminal is, for example, a non-inverting input terminal of the operational amplifier OPB. The operational amplifier OPB is the first operational amplifier. The power supply compensation voltage VB is a voltage used to perform compensation corresponding to the power supply voltage VDD, and it varies accordingly with changes in the power supply voltage VDD. For example, the power supply compensation voltage VB increases when the power supply voltage VDD rises and decreases when the power supply voltage VDD falls.

[0067] Thus, the first input terminal of the operational amplifier OPB of the correction voltage output circuit 70 is input with a power compensation voltage VB corresponding to the power supply voltage VDD, and the second input terminal is input with an offset adjustment voltage VOF. Therefore, a correction voltage VCR reflecting the power supply voltage VDD and the offset adjustment voltage VOF can be output from the output terminal. For example, the correction voltage output circuit 70 can output the correction voltage VCR as the subtraction voltage obtained by multiplying the offset adjustment voltage VOF by a given coefficient and the voltage obtained by multiplying the power supply voltage VDD by a given coefficient. As a result, the temperature detection voltage VTS from the temperature sensor 50 can be corrected by the correction voltage VCR reflecting the power supply voltage VDD and the offset adjustment voltage VOF, and the corrected temperature detection voltage VTS2 can be output to the temperature compensation circuit 40.

[0068] Specifically, the correction voltage output circuit 70 includes resistors RB1 and RB2 connected in series between the input node NVD of the power supply voltage VDD and node NB3 of the output terminal of the operational amplifier OPB. Resistor RB1 is the first resistor, and resistor RB2 is the second resistor. Furthermore, the power supply compensation voltage VB from the connection node NB1 of resistors RB1 and RB2 is supplied to the first input terminal of the operational amplifier OPB. For example, the power supply compensation voltage VB is input to the connection node NB1, which is the inverting input terminal of the first input terminal of the operational amplifier OPB. Additionally, the offset adjustment voltage VOF is input to node NB2, which is the non-inverting input terminal of the second input terminal of the operational amplifier OPB. Thus, the resistor divider voltage of resistors RB1 and RB2 can be input as the power supply compensation voltage VB to the first input terminal of the operational amplifier OPB. Therefore, the power supply compensation voltage VB, which varies according to the power supply voltage VDD, is input to the first input terminal of the operational amplifier OPB, and the offset adjustment voltage VOF is input to the second input terminal of the operational amplifier OPB. Therefore, the correction voltage output circuit 70 is able to output a correction voltage VCR that reflects the power supply voltage VDD and the offset adjustment voltage VOF.

[0069] For example, if the resistance values ​​of resistors RB1 and RB2 are R1 and R2 respectively, the correction voltage VCR is expressed as shown in equation (1).

[0070]

[0071] In this way, the operational amplifier OPB becomes an inverting amplifier of the input offset adjustment voltage VOF and the power supply voltage VDD. It outputs, for example, a subtraction operation whereby the voltage obtained by multiplying the offset adjustment voltage VOF by a coefficient (1+R2 / R1) and the voltage obtained by multiplying the power supply voltage VDD by a coefficient (R2 / R1) as the correction voltage VCR. Therefore, the correction voltage output circuit 70 outputs the correction voltage VCR, which reflects the power supply voltage VDD and the offset adjustment voltage VOF.

[0072] In addition, Figure 5In this circuit, the correction circuit 74 includes an operational amplifier OPC. The first input terminal of the OPC receives a compensation voltage VC that varies according to the correction voltage VCR, and the second input terminal receives a temperature detection voltage VTS from the temperature sensor 50. The corrected temperature detection voltage VTS2 is output from the output terminal. The first input terminal is, for example, an inverting input terminal of the OPC, and the second input terminal is, for example, a non-inverting input terminal of the OPC. The OPC is a second operational amplifier. The compensation voltage VC is a voltage used to perform temperature compensation corresponding to the correction voltage VCR, and it varies accordingly with the correction voltage VCR. For example, the compensation voltage VC increases when the correction voltage VCR increases and decreases when the correction voltage VCR decreases.

[0073] Thus, the first input terminal of the operational amplifier OPC of the correction circuit 74 is input with a compensation voltage VC corresponding to the correction voltage VCR, and the second input terminal is input with a temperature detection voltage VTS from the temperature sensor 50. Therefore, a temperature detection voltage VTS2 that reflects the correction voltage VCR can be output from the output terminal. For example, the correction circuit 74 can output the corrected temperature detection voltage VTS2 as a subtraction or addition operation voltage obtained by multiplying the temperature detection voltage VTS by a given coefficient and the voltage obtained by multiplying the correction voltage VCR by a given coefficient. Thus, the temperature detection voltage VTS from the temperature sensor 50 can be corrected by the correction voltage VCR that reflects the power supply voltage VDD and the offset adjustment voltage VOF, and the corrected temperature detection voltage VTS2 can be output to the temperature compensation circuit 40.

[0074] Specifically, the correction circuit 74 includes resistors RC1 and RC2 connected in series between the input node NVC of the correction voltage VCR and node NC3 of the output terminal of the operational amplifier OPC. Resistor RC1 is the first resistor, and resistor RC2 is the second resistor. Furthermore, the compensation voltage VC from the connection node NC1 of resistors RC1 and RC2 is supplied to the first input terminal of the operational amplifier OPC. For example, the compensation voltage VC is input to the connection node NC1 of the first input terminal of the operational amplifier OPC, which is the inverting input terminal. Additionally, the temperature detection voltage VTS is input to node NC2 of the second input terminal of the operational amplifier OPC, which is the non-inverting input terminal. Thus, the resistor divider voltage of resistors RC1 and RC2 can be used as the compensation voltage VC input to the first input terminal of the operational amplifier OPC. Therefore, the first input terminal of the operational amplifier OPC receives the compensation voltage VC, which varies according to the correction voltage VCR, and the second input terminal of the operational amplifier OPC receives the temperature detection voltage VTS. Therefore, the correction circuit 74 can output the corrected temperature detection voltage VTS2 as the voltage after correcting the temperature detection voltage VTS from the temperature sensor 50 using the correction voltage VCR, which varies according to the power supply voltage VDD and the offset adjustment voltage VOF.

[0075] For example, if the resistance values ​​of resistors RC1 and RC2 are R3 and R4, the corrected temperature detection voltage VTS2 of the correction circuit 74 is expressed as shown in equation (2).

[0076]

[0077] Thus, the operational amplifier OPC becomes an inverting amplifier of the input temperature detection voltage VTS and correction voltage VCR, as shown in equation (2) above. For example, a subtraction operation voltage is performed between the temperature detection voltage VTS multiplied by a coefficient (1+R4 / R3) and the correction voltage VCR multiplied by a coefficient (R4 / R3), resulting in the corrected temperature detection voltage VTS2. Furthermore, the correction voltage VCR, as shown in equation (1) above, varies according to the power supply voltage VDD and the offset adjustment voltage VOF. Therefore, as shown in equation (3) above, the correction circuit 74 outputs the corrected temperature detection voltage VTS2, which is the temperature detection voltage VTS from the temperature sensor 50, based on the power supply voltage VDD and the offset adjustment voltage VOF.

[0078] Next, the correction based on the correction voltage VCR will be explained in detail. In this embodiment, the resistance ratio Rr = (R2 / R1) of the resistors RB1 and RB2 in the correction voltage output circuit 70 is variable, or at least one of the resistance values ​​R1 of resistor RB1 and R2 of resistor RB2 is variable. In this way, it is possible to control how the power supply voltage VDD and the offset adjustment voltage VOF are reflected in the correction voltage VCR according to the resistance ratio Rr and resistance values ​​of resistors RB1 and RB2.

[0079] Figure 6 A detailed structural example of the correction voltage output circuit 70 is shown. Figure 6 In this circuit, multiple resistors are connected in series between the input node NVD of the power supply voltage VDD and the node NB3 of the output terminal of the operational amplifier OPB. Furthermore, the nodes of the connection taps of these multiple resistors are connected as connection nodes NB1 to the first input terminal (inverting input terminal) of the operational amplifier OPB. For example, multiple switches are provided between the multiple connection taps and the first input terminal of the operational amplifier OPB. Any one of these switches is turned on based on adjustment data, thereby connecting the connection tap connected to the turned-on switch to the first input terminal of the operational amplifier OPB. Resistor RB1 corresponds to the resistance between the connection tap and the input node NVD of the power supply voltage VDD, and resistor RB2 corresponds to the resistance between the connection tap and the node NB3 of the output terminal. Thus, according to the adjustment data of the correction voltage output circuit 70, the resistance ratio Rr = (R2 / R1) of resistors RB1 and RB2 can be variably controlled. Thus, as shown in equation (1) above, VCR = (1 + R2 / R1)VOF - (R2 / R1)VDD, it is possible to variably control how the power supply voltage VDD and the offset adjustment voltage VOF are reflected in the correction voltage VCR.

[0080] Figure 7 This is an explanatory diagram regarding the setting example of the calibration voltage VCR. In Figure 7 In the diagram, the horizontal axis represents the power supply voltage VDD, and the vertical axis represents the calibration voltage VCR. C1 represents the characteristic of the temperature sensing voltage VTS2 when the resistance ratio Rr = (R2 / R1) is minimized, adjusted using n = 4 bits of adjustment data. C2 represents the characteristic of the temperature sensing voltage VTS2 when the resistance ratio Rr = (R2 / R1) is maximized. Alternatively, the adjustment data can be used to control only the resistance value R1 of resistor RB1, or only the resistance value R2 of resistor RB2, or both the resistance values ​​of R1 and R2. In this case, Figure 7 C1 represents the characteristic of the temperature sensing voltage VTS2 when the resistance value R2 is at its minimum, and C2 represents the characteristic of the temperature sensing voltage VTS2 when the resistance value R2 is at its maximum. Furthermore, the adjustment data of the correction voltage output circuit 70 is, for example, n bits of data (n is an integer greater than 2), stored, for example... Figure 2 In the non-volatile memory 110.

[0081] like Figure 7 As shown, the correction voltage output circuit 70 outputs a correction voltage VCR that decreases monotonically with the rise of the power supply voltage VDD and whose voltage change is variable relative to the change in the power supply voltage VDD. This correction voltage VCR, which decreases monotonically with the rise of the power supply voltage VDD and whose voltage change is variable relative to the change in the power supply voltage VDD, is used for temperature compensation to correct the temperature detection voltage VTS of the temperature sensor 50. This prevents errors in the oscillation frequency caused by excessive temperature compensation of the temperature compensation voltage VCP. Furthermore, the correction voltage VCR can also be a voltage that increases monotonically with the rise of the power supply voltage VDD. For example, when using a variable capacitor circuit with negative characteristics as the variable capacitor circuit for temperature compensation, the correction voltage VCR can simply increase monotonically with the rise of the power supply voltage VDD.

[0082] Furthermore, the correction circuit 74 uses such a correction voltage VCR to correct the temperature detection voltage VTS of the temperature sensor 50 and outputs the corrected temperature detection voltage VTS2. For example, according to the above equations (1) and (2), the corrected temperature detection voltage VTS2 is expressed by the temperature detection voltage VTS, the offset adjustment voltage VOF, and the power supply voltage VDD as shown in equation (3).

[0083]

[0084] Therefore, as shown in equation (3) above, the corrected temperature detection voltage VTS2 changes according to the change of the power supply voltage VDD, and can realize temperature compensation that reflects the change of the power supply voltage VDD.

[0085] Figure 8 An example is shown illustrating the temperature characteristics of the temperature sensing voltage. For example... Figure 8 As shown, the temperature sensing voltage has, for example, a negative temperature characteristic relative to temperature T. Furthermore, Figure 8 E1 represents the temperature characteristic of the temperature sensing voltage VTS2 when the power supply voltage VDD is a typical voltage, E2 represents the temperature characteristic when VDD rises, and E3 represents the temperature characteristic when VDD falls.

[0086] For example, when the power supply voltage VDD rises, the temperature at the location of temperature sensor 50 is T = t1. In this case, the correction circuit 74 outputs a voltage of VTS2 = V1 as the corrected temperature detection voltage. Furthermore, as... Figure 8As shown, the voltage VTS2 = V1 corresponds to the temperature detection voltage at temperature T = t2 when the power supply voltage VDD is at a typical voltage. That is, when the power supply voltage VDD rises, the correction circuit 74 outputs a temperature detection voltage VTS2 corresponding to a temperature T = t2 that is lower than the temperature T = t1 at the location of the temperature sensor 50.

[0087] Furthermore, when the power supply voltage VDD decreases, the temperature at the location of temperature sensor 50 is T = t3. In this case, the correction circuit 74 outputs a temperature detection voltage VTS2 = V1 corresponding to the temperature T = t2 when the power supply voltage VDD is at its typical value, as the corrected temperature detection voltage. That is, when the power supply voltage VDD decreases, the correction circuit 74 outputs a temperature detection voltage VTS2 corresponding to a temperature T = t2 that is higher than the temperature T = t3 at the location of temperature sensor 50.

[0088] As described above, when the power supply voltage VDD rises, the temperature rise of the circuit device 20 is greater than that of the oscillator 10, and the temperature at the location of the temperature sensor 50 of the circuit device 20 is higher than that of the oscillator 10.

[0089] Therefore, as Figure 8 As shown, when the power supply voltage VDD rises, the correction circuit 74 outputs a temperature detection voltage VTS2 corresponding to a temperature T=t2 that is lower than temperature T=t1. Therefore, the temperature detection voltage VTS2 corresponding to the temperature at the position of the oscillator 10, which is lower than the temperature at the position of the circuit device 20, is input to the temperature compensation circuit 40, preventing [further damage / damage]. Figure 3 Excessive temperature compensation is shown in A4 and A5. Furthermore, when the power supply voltage VDD decreases, the correction circuit 74 outputs a temperature detection voltage VTS2 corresponding to a temperature T=t2 that is higher than temperature T=t3. This prevents excessive temperature compensation. Figure 3 The excessive temperature compensation shown in A4 and A5.

[0090] In addition, in the above formula (3), the coefficient of the power supply voltage VDD is set as cf(Rr)=(R4 / R3)(R2 / R1)=(R4 / R3)Rr. Figure 6 The larger the resistance ratio Rr = R2 / R1 in the correction voltage output circuit 70, the larger the coefficient cf(Rr). For example, the smaller the oscillator 4 and the smaller its heat capacity, the greater the temperature change caused by fluctuations in the power supply voltage VDD. Therefore, if... Figure 7As shown in C2, increasing the resistance ratio Rr = R2 / R1 increases the coefficient cf(Rr). Thus, in the correction circuit 74, by setting the resistance ratio Rr and the resistance values ​​R1 and R2, the coefficient cf(Rr) of the power supply voltage VDD can be adjusted. Therefore, by setting the resistance ratio Rr and the resistance values ​​R1 and R2 according to the heat capacity of the oscillator 4, appropriate temperature compensation corresponding to the heat capacity of the oscillator 4 can be achieved. For example, as described above, the adjustment data for the resistance ratio Rr and the resistance values ​​R1 and R2 can be stored in the non-volatile memory 110. Therefore, by writing appropriate adjustment data corresponding to the product of the oscillator 4 or circuit device 20 into the non-volatile memory 110, appropriate temperature compensation corresponding to the heat capacity of the product can be achieved.

[0091] Figure 9 This is an explanatory diagram of the correction method in this embodiment. Figure 9 D1 represents the frequency-temperature characteristic of the oscillator 10 before the power supply voltage VDD rises, and D2 represents the frequency-temperature characteristic of the oscillator 10 after the power supply voltage VDD rises. D1 and D2 show the case where temperature compensation is appropriately performed based on the temperature TX of the oscillator 10. On the other hand, D3 represents the frequency-temperature characteristic of the temperature compensation voltage VCP when excessive temperature compensation is performed based on the detected temperature TJ of the temperature sensor 50 of the circuit device 20 after the power supply voltage VDD rises. If a variable capacitor circuit 32 with a positive capacitance change characteristic is used as described above, when the temperature compensation voltage VCP rises, the capacitance increases and the oscillation frequency decreases; when the temperature compensation voltage VCP falls, the capacitance decreases and the oscillation frequency increases. Therefore, the frequency-temperature characteristic of the oscillator 10 is compensated by the temperature compensation voltage VCP with a frequency-temperature characteristic like D3.

[0092] Furthermore, in Figure 9 In this embodiment, when the power supply voltage VDD rises, excessive temperature compensation based on the detected temperature TJ of the temperature sensor 50 is performed, as shown in D4, and temperature compensation based on the temperature compensation voltage VCP shown in D3 is also performed. Therefore, an error in the oscillation frequency is generated due to the temperature compensation error. Therefore, the correction circuit 74 of this embodiment performs the correction shown in D5, so that the excessive temperature compensation shown in D4 is not performed. Thus, the error in the oscillation frequency caused by excessive temperature compensation can be suppressed.

[0093] That is, a temperature difference TJ-TX is generated between the temperature TJ detected by the temperature sensor 50 of the circuit device 20 and the temperature TX of the oscillator. For example... Figure 3 A4, A5 Figure 4As shown in B4 and B5, the greater the change in power supply voltage VDD, the greater the temperature difference TJ-TX. Therefore, in this embodiment, when the temperature difference TJ-TX between the temperature sensor 50's detected temperature TJ and the oscillator 10's temperature TX changes due to the change in power supply voltage VDD, the correction circuit 74 causes the temperature detection voltage VTS2 to change by a voltage change corresponding to the temperature difference TJ-TX. For example, the correction circuit 74 performs correction so that the temperature detection voltage VTS2 changes in a manner that the greater the temperature difference TJ-TX, the greater the voltage change. This correction is achieved by changing the correction voltage VCR from the correction voltage output circuit 70. For example, in Figure 3 In case A5, where VDD is +5%, the temperature difference TJ-TX between the temperature TJ detected by the temperature sensor 50 and the temperature TX of the oscillator 10 is larger than in case A5, where VDD is +10%. Therefore, in case A5, where the power supply voltage VDD fluctuates significantly and the temperature difference TJ-TX increases, the correction circuit 74 performs correction by causing the temperature detection voltage VTS2 to change with a larger voltage change compared to case A4. Figure 4 As shown, when the power supply voltage VDD decreases, the correction circuit 74 also performs correction by changing the temperature detection voltage VTS2 in such a way that the larger the temperature difference TJ-TX, the greater the voltage change. In this way, even when the temperature difference TJ-TX between the temperature sensor 50's detected temperature TJ and the oscillator 10's temperature TX changes due to variations in the power supply voltage VDD, the temperature compensation error caused by the temperature difference TJ-TX can be reduced, thereby improving the accuracy of the oscillation frequency.

[0094] Thus, in Figure 9 As shown in D5, a correction is performed to restore the frequency-temperature characteristic shown in D3, which has been over-compensated for temperature, to the appropriate frequency-temperature characteristic shown in D2. That is, a correction is performed along the horizontal axis, which is the temperature T axis, to shift the frequency-temperature characteristic in the opposite direction to the direction of the over-compensation. This allows for the reduction of errors caused by over-compensation for temperature, thereby improving the accuracy of the oscillation frequency.

[0095] 3. Temperature compensation circuit

[0096] Figure 10 An example of the structure of the temperature compensation circuit 40 is shown. Furthermore, the temperature compensation circuit 40 is not limited to... Figure 10 The structure can implement various transformations, such as omitting some of the structural elements, adding other structural elements, or replacing some structural elements with other structural elements.

[0097] The temperature compensation circuit 40 outputs a temperature compensation voltage VCP using a polynomial approximation with temperature as the variable. This temperature compensation circuit 40 includes a current generation circuit 42 and a current-to-voltage conversion circuit 46. The current generation circuit 42 generates a functional current based on the temperature detection result from the temperature sensor 50. For example, by correcting the temperature detection voltage VTS, which is the temperature detection result from the temperature sensor 50, via the correction circuit 74, the current generation circuit 42 generates a functional current for temperature compensation of the frequency-temperature characteristics of the oscillator 10 based on the corrected temperature detection voltage VTS2 from the correction circuit 74. Then, the current-to-voltage conversion circuit 46 converts the functional current from the current generation circuit 42 into a voltage and outputs the temperature compensation voltage VCP. Specifically, the current-to-voltage conversion circuit 46 outputs the temperature compensation voltage VCP through the operational amplifier OPD1.

[0098] 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 approximating a first-order function based on the temperature detection voltage VTS2. 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 higher-order correction circuit 44 outputs a higher-order current approximating a higher-order function to the current-to-voltage conversion circuit 46 based on the temperature detection voltage VTS2. 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 third-order current approximating a third-order function. In this case, the higher-order correction circuit 44 includes a differential circuit that performs differential operation based on the temperature detection voltage VTS2 and a differential circuit that outputs a third-order current by performing differential operation based on the output voltage of the differential circuit and the temperature detection voltage VTS2. Additionally, the higher-order correction circuit 44 may also include a correction circuit that performs corrections of four or more orders. For example, the higher-order correction circuit 44 may also include a fourth-order correction circuit that outputs a fourth-order current that approximates a fourth-order function and a fifth-order correction circuit that outputs a fifth-order current that approximates a fifth-order function.

[0099] The primary correction circuit 43 includes operational amplifier OPD2 and resistors RD1 and RD2. Additionally, the primary correction circuit 43 may include a resistor RD3 with a variable resistance value. The non-inverting input terminal of operational amplifier OPD2 is supplied with a reference voltage VRC. Resistor RD1 is positioned between node ND1 of the temperature sensing voltage VTS2 and node ND2 of the inverting input terminal of operational amplifier OPD2. Resistor RD2 is positioned between node ND2 of the inverting input terminal of operational amplifier OPD2 and node ND3 of the output terminal of operational amplifier OPD2. Resistor RD3 is positioned between node ND3 of the output terminal of operational amplifier OPD2 and node ND4 of the output terminal of current generation circuit 42.

[0100] The current-to-voltage conversion circuit 46 adds the primary current and the higher-order current, and performs current-to-voltage conversion on the added current, thereby outputting a temperature-compensated voltage VCP. This generates a temperature-compensated voltage VCP that approximates a polynomial function. Specifically, the current-to-voltage conversion circuit 46 includes an operational amplifier OPD1 and feedback circuit elements. The non-inverting input terminal of the operational amplifier OPD1 is connected to a reference voltage VRC, and the inverting input terminal is connected to the output node ND4 of the current generation circuit 42. The feedback circuit elements are circuit elements disposed between the output terminal and the inverting input terminal of the operational amplifier OPD1. Figure 10 In the circuit, a resistor RD and a capacitor CD are connected in parallel between the output terminal and the inverting input terminal of the operational amplifier OPD1 as feedback circuit elements.

[0101] so, Figure 10 The temperature compensation circuit 40 includes: a current generation circuit 42 having a primary correction circuit 43 and a higher-order correction circuit 44 for the input corrected temperature detection voltage VTS2, through which a function current is generated; and a current-to-voltage conversion circuit 46, which converts the function current into a voltage and outputs a temperature compensation voltage VCP. According to this structure, the temperature compensation circuit 40 can convert the function current generated by the current generation circuit 42 based on the corrected temperature detection voltage VTS2 into a voltage and output it as the temperature compensation voltage VCP via the current-to-voltage conversion circuit 46.

[0102] 4. Temperature sensor

[0103] Next, an example of the structure of the temperature sensor 50 will be described. Figure 11 A first structural example of a temperature sensor 50 is shown. The temperature sensor 50 includes a constant current source IS1, a bipolar transistor BPE1, and a resistor RE1. The constant current source IS1, resistor RE1, and bipolar transistor BPE1 are connected in series between the VDD node and the GND node. Specifically, the connection node between the constant current source IS1 and one end of the resistor RE1 is connected to the base of the bipolar transistor BPE1, and the other end of the resistor RE1 is connected to the collector of the bipolar transistor BPE1. In addition, the emitter of the bipolar transistor BPE1 is connected to the GND node.

[0104] exist Figure 11 In the context of constant current source IS1, the current flowing through IS1 is IE, the resistance of resistor RE1 is R1, and the base / emitter voltage of bipolar transistor BPE1 is VBE1, the temperature detection voltage VTS is expressed as shown in equation (4).

[0105] VTS=VBE1-IE×R1···(4)

[0106] The base / emitter voltage VBE1 of the bipolar transistor BPE1 has a negative temperature characteristic; therefore, the temperature sensing voltage VTS also has a negative temperature characteristic.

[0107] Figure 12 The second structural example of temperature sensor 50 is shown. Figure 12 The temperature sensor 50 includes constant current sources IS1 and IS2, bipolar transistors BPE1 and BPE2, and resistors RE1 and RE3.

[0108] The connection structure of constant current source IS1, bipolar transistor BPE1, and resistor RE1 is as follows: Figure 11 The structure is the same as the first example. Furthermore, the constant current source IS2, resistor RE3, and bipolar transistor BPE2 are connected in series between the VDD node and the collector node of bipolar transistor BPE1. Specifically, the connection node between the constant current source IS2 and one end of resistor RE3 is connected to the base of bipolar transistor BPE2, and the other end of resistor RE3 is connected to the collector of bipolar transistor BPE2. Additionally, the emitter of bipolar transistor BPE2 is connected to the collector of bipolar transistor BPE1.

[0109] exist Figure 12 In this diagram, let the collector voltage of bipolar transistors BPE1 and BPE2 be VGA, the current flowing through constant current sources IS1 and IS2 be IE, and the resistance values ​​of resistors RE1 and RE3 be R1 and R3, respectively. Furthermore, let the base-emitter voltages of bipolar transistors BPE1 and BPE2 be VBE1 and VBE2, respectively. Therefore, the voltages VGA and VTS are expressed as shown in equations (5) and (6). Additionally, the offset voltage of operational amplifier OPE is assumed to be zero.

[0110] VGA=VBE1-IE×R1···(5)

[0111] VTS = VBE2 - IE × R3 + VGA

[0112] =VBE1+VBE2-IE×(R1+R3)···(6)

[0113] exist Figure 12 In the second structural example, two bipolar transistors BPE1 and BPE2 are provided, therefore, the two base-emitter voltages VBE1 and VBE2 are added together. Thus, with... Figure 11 Compared to the first structural example, the slope of the temperature detection voltage VTS relative to the temperature can be increased, and a temperature detection voltage VTS with high sensitivity to temperature can be generated.

[0114] Figure 13 The structure of temperature sensor 58, which is a comparative example of this embodiment, is shown. Figure 13 The temperature sensor 58 is the structure disclosed in Patent Document 1. Figure 13 In the comparative examples, relative to Figure 12 The structure also includes a buffer circuit 59 comprising resistors RE2 and RE4 with variable resistance values, an operational amplifier OPE, and resistors RE5 and RE6. Furthermore, by changing the resistance values ​​of resistors RE2 and RE4, zero-order offset adjustment of the temperature sensing voltage VTS can be performed. Therefore, the temperature sensing voltage VTS includes an offset component, enabling zero-order offset adjustment of the temperature sensor 58. Additionally, in Figure 13 In the middle, by setting the buffer circuit 59, the temperature detection voltage VTS can be output through the operational amplifier OPE with high driving capability.

[0115] Figure 14 The structure of the correction circuit 52 of the comparative example is shown. Figure 14 The correction circuit 52 is the structure disclosed in Patent Document 1. Figure 14 In the calibration circuit 52, there are an offset generation circuit 54 and an adder circuit 55. The offset generation circuit 54 includes an operational amplifier OPF1 and resistors RF1, RF2, RF3, and RF4. It receives the input power supply voltage VDD and the temperature detection voltage VTS to generate an offset voltage VDDOF for VDD compensation. This offset voltage VDDOF is a voltage that changes in conjunction with the power supply voltage VDD and is used to compensate for changes in the power supply voltage VDD. The adder circuit 55 includes an operational amplifier OPF2 and resistors RF5, RF6, RF7, and RF8. It adds the temperature detection voltage VTS from the temperature sensor 58 and the offset voltage VDDOF for VDD compensation, outputting a temperature detection voltage VTSVDD.

[0116] exist Figure 13 In the comparative example temperature sensor 58, the temperature detection voltage VTS is offset adjusted based on the zero-order correction data corresponding to the zero-order coefficients of the polynomial in the polynomial approximation of the temperature compensation characteristic. For example, in temperature sensor 58, zero-order offset adjustment can be performed by adjusting the resistance values ​​of resistors RE2 and RE4.

[0117] However, in Figure 13 In the comparative example temperature sensor 58, since the zero-time offset adjustment is performed at multiple locations, there is a problem of linear degradation in the offset adjustment. For example, as with the adjustment of the resistance value of resistor RE2 and the adjustment of the resistance value of resistor RE4, the offset adjustment of the temperature detection voltage VTS is performed at multiple locations, thus causing linear degradation in the offset adjustment. For example, in order to ensure that the offset adjustment can be performed appropriately even with changes in the manufacturing process, the adjustment range of resistor RE2 is set to overlap with the adjustment range of resistor RE4, but linear degradation occurs at the location corresponding to the overlapping adjustment range. Furthermore, in Figure 13 In the comparative example, there is also the problem that the slope characteristic of the temperature detection voltage VTS relative to temperature changes due to offset adjustment.

[0118] For example, Figure 15 Shown in Figure 13 The temperature characteristics of the temperature detection voltage VTS in the comparative example temperature sensor 58 when the offset adjustment voltage changes zero times. For example... Figure 15 As shown, in the temperature sensor 58 of the comparative example, the slope of the temperature detection voltage VTS relative to the temperature T varies depending on the magnitude of the offset adjustment voltage. For example, in Figure 15 In this process, when the offset adjustment voltage is large, the slope of the temperature sensing voltage VTS increases, and when the offset adjustment voltage is small, the slope decreases. Thus, when the slope of the temperature sensing voltage VTS depends on the offset adjustment voltage, it is difficult to achieve proper temperature compensation.

[0119] in addition, Figure 16 This is a graph illustrating the linearity of the offset adjustment voltage of the temperature sensor 58 in the comparative example. In the comparative example, the offset adjustment voltage is adjusted by setting the offset adjustment data register, but as... Figure 16 As shown, the linearity of the offset adjustment deteriorates, for example, at the location corresponding to the overlap range of the adjustment. Thus, when the linearity of the offset adjustment deteriorates, it becomes difficult to achieve proper temperature compensation.

[0120] In contrast, Figure 17 This is a graph illustrating the linearity of the offset adjustment voltage in this embodiment. For example... Figure 17 As shown, according to this embodiment, with Figure 16 Compared to the comparative example, it can significantly improve the linearity of the offset adjustment voltage.

[0121] Furthermore, in comparative examples, such as Figure 13 , Figure 14 As shown, the temperature sensor 58 includes an operational amplifier OPE that serves as a buffer amplifier for the temperature detection voltage VTS. The correction circuit 52 includes an operational amplifier OPF1 that generates the offset voltage VDDOF for VDD compensation and an operational amplifier OPF2 that serves as an adder amplifier. Therefore, a total of three amplifiers are required, which leads to problems such as increased circuit area or increased current consumption.

[0122] In contrast, Figure 5 In this embodiment, only two operational amplifiers, OPB and OPC, acting as inverting amplifiers, are needed. Therefore, with Figure 13 , Figure 14 Compared to comparative examples, it has advantages such as reducing the number of amplifiers, minimizing circuit area, and reducing current consumption. For example, in Figure 5In this circuit, the temperature detection voltage VTS from the temperature sensor 50 is input to the gate of the differential transistor at the non-inverting input terminal of the operational amplifier OPC, which serves as the correction circuit 74. Therefore, it is not necessary to... Figure 13 The operational amplifier OPE of the buffer circuit 59 shown. Additionally, the operational amplifier OPB of the correction voltage output circuit 70, which receives the input power supply voltage VDD, also functions as a buffer amplifier for the offset adjustment circuit 60. As a result, in Figure 5 In, with Figure 13 , Figure 14 Compared to the comparative example, it can reduce the number of amplifiers, thereby reducing the circuit area and the current consumption.

[0123] In addition, in this embodiment, such as Figure 10 As shown, the temperature detection voltage VTS2, corrected by the correction circuit 74, is input to the higher-order correction circuit 44 of the temperature compensation circuit 40. This enables temperature compensation correction, including higher-order correction by the higher-order correction circuit 44.

[0124] For example, when zero offset adjustment is performed, in addition to zero offset, the inflection point temperature in higher-order correction also changes. For example, if the ambient temperature is t, the detection temperature of temperature sensor 50 is t0, the change in inflection point temperature is Δt0, the change in offset adjustment voltage of zero is ΔV0, and the coefficients are a and b, the temperature compensation voltage VCP is expressed as shown in equation (7).

[0125] VCP = a(t - t0 - Δt0) 3 +b(t-t0-Δt0)+VOF+ΔV0…(7)

[0126] In equation (7) above, the term with coefficient a corresponds to a higher-order correction of degree 3. Furthermore, as... Figure 18 As shown, the inflection point temperature of the higher-order correction also changes according to the change in the offset adjustment voltage. Therefore, by inputting the temperature detection voltage VTS2, which has been corrected to correspond to the temperature difference between the circuit device 20 and the oscillator 10, into the higher-order correction circuit 44 of the temperature compensation circuit 40, appropriate temperature compensation corresponding to the change in the inflection point temperature can be achieved.

[0127] 5. Oscillator

[0128] Figure 19The first construction example of the oscillator 4 according to this embodiment is shown. The oscillator 4 includes an oscillator 10, a circuit device 20, and a package 15 for housing the oscillator 10 and the circuit device 20. The package 15 is formed, for example, of ceramic, and has a housing space inside, in which the oscillator 10 and the circuit device 20 are housed. The housing space is hermetically sealed, preferably in a near-vacuum state, i.e., a depressurized state. The package 15 can adequately protect the oscillator 10 and the circuit device 20 from the effects of impact, dust, heat, moisture, etc.

[0129] Package 15 includes a base 16 and a cover 17. Specifically, package 15 consists of a base 16 supporting the oscillator 10 and the circuit device 20, and a cover 17 that engages with the upper surface of the base 16 to form a receiving space between the cover and the base 16. The oscillator 10 is supported by terminal electrodes on a stepped portion provided inside the base 16. The circuit device 20 is disposed on the inner bottom surface of the base 16. Specifically, the circuit device 20 is disposed with its active surface facing the inner bottom surface of the base 16. The active surface is the surface of the circuit device 20 on which circuit elements are formed. Furthermore, 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 by means of conductive bumps BMP. The conductive bumps BMP are, for example, metal bumps, and the oscillator 10 and the circuit device 20 are electrically connected via these bumps BMP, internal wiring of package 15, terminal electrodes, etc. Furthermore, the circuit device 20 is electrically connected to the external terminals 18 and 19 of the oscillator 4 via internal wiring of the bump BMP or 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 external devices via external wiring. The external wiring may be, for example, wiring formed on the circuit board on which the external device is mounted. Thus, clock signals can be output to external devices.

[0130] In addition, Figure 19 In this embodiment, the circuit device 20 is mounted upside down with its active surface facing downwards, but this embodiment is not limited to this mounting. For example, the circuit device 20 may also be mounted with its active surface facing upwards. That is, the circuit device 20 may be mounted with its active surface facing the oscillator 10.

[0131] Figure 20A second construction example of the oscillator 4 is shown. The oscillator 4 includes an oscillator 10, a circuit device 20, and a package 15 housing the oscillator 10 and the circuit device 20. The package 15 has a base 16 and a cover 17. The base 16 has a first substrate 6 serving as an intermediate substrate, a second substrate 7 stacked on the upper surface of the first substrate 6 in a generally rectangular frame shape, and a third substrate 8 stacked on the bottom surface of the first substrate 6 in a generally rectangular frame shape. The cover 17 is bonded to the upper surface of the second substrate 7, and the oscillator 10 is housed in the housing space S1 formed by the first substrate 6, the second substrate 7, and the cover 17. For example, the oscillator 10 is hermetically sealed in the housing space S1, preferably in a near-vacuum state, i.e., a depressurized state. This allows the oscillator 10 to be appropriately protected from impacts, dust, heat, moisture, etc. In addition, the circuit device 20, which serves as a semiconductor chip, is housed in the housing space S2 formed by the first substrate 6 and the third substrate 8. Furthermore, external terminals 18 and 19 for external connection of the oscillator 4 are formed on the bottom surface of the third substrate 8.

[0132] Furthermore, within the storage space S1, the oscillator 10 is connected to a first electrode terminal (not shown) and a second electrode terminal (not shown) formed on the upper surface of the first substrate 6 via conductive connecting portions CDC1 and CDC2. The conductive connecting portions CDC1 and CDC2 can be implemented, for example, by conductive bumps such as metal bumps, or by conductive adhesives. Specifically, for example, a first electrode pad (not shown) formed at one end of the tuning fork-shaped oscillator 10 is connected to a first electrode terminal formed on the upper surface of the first substrate 6 via the conductive connecting portion CDC1. The first electrode terminal is also electrically connected to the pad PX1 of the circuit device 20. Additionally, a second electrode pad (not shown) formed at the other end of the tuning fork-shaped oscillator 10 is connected to a second electrode terminal formed on the upper surface of the first substrate 6 via the conductive connecting portion CDC2. The second electrode terminal is also electrically connected to the pad PX2 of the circuit device 20. Therefore, one end of the oscillator 10 and the other end can be electrically connected to the pads PX1 and PX2 of the circuit device 20 via conductive connection portions CDC1 and CDC2. Furthermore, conductive bumps BMP are formed on the multiple pads of the circuit device 20, which serves as a semiconductor chip, and these conductive bumps BMP are connected to multiple electrode terminals formed on the bottom surface of the first substrate 6. Moreover, the electrode terminals connected to the pads of the circuit device 20 are electrically connected to the external terminals 18 and 19 of the oscillator 4 via internal wiring or the like.

[0133] Alternatively, the oscillator 4 can also be a wafer-level packaged (WLP) oscillator. In this case, the oscillator 4 includes: a base having a semiconductor substrate and a through electrode that passes between a first surface and a second surface of the semiconductor substrate; an oscillator 10 fixed to the first surface of the semiconductor substrate via conductive bonding members such as metal bumps; and an external terminal disposed on the second surface of the semiconductor substrate across an insulating layer such as a redistribution wiring layer. Furthermore, an integrated circuit, serving as a circuit device 20, is formed on either the first or second surface of the semiconductor substrate. In this case, by bonding a first semiconductor wafer with multiple substrates on which the oscillator 10 and the integrated circuit are disposed to a second semiconductor wafer with multiple covers, the multiple substrates and multiple covers are joined, and then the oscillator 4 is monolithically produced using a dicing saw or the like. This enables the realization of a wafer-level packaged oscillator 4, allowing for the manufacture of a high-throughput and low-cost oscillator 4.

[0134] As explained above, the circuit arrangement of this embodiment operates by being supplied with a power supply voltage. This circuit arrangement includes: an oscillation circuit that causes an oscillator to oscillate; a temperature sensor that outputs a temperature detection voltage; and an offset adjustment circuit that outputs an offset adjustment voltage for the temperature detection voltage. Furthermore, the circuit arrangement includes: a correction voltage output circuit that receives the power supply voltage and the offset adjustment voltage as input and outputs a correction voltage that varies according to the power supply voltage and the offset adjustment voltage; a correction circuit that receives the temperature detection voltage and the correction voltage as input and outputs a temperature detection voltage corrected using the correction voltage; and a temperature compensation circuit that performs temperature compensation of the oscillation frequency of the oscillation circuit based on the corrected temperature detection voltage.

[0135] According to this embodiment, an offset adjustment voltage is generated by an offset adjustment circuit, and a correction voltage generated by the power supply voltage and the offset adjustment voltage is used to correct the temperature detection voltage of the temperature sensor. Temperature compensation is then performed using the corrected temperature detection voltage. Therefore, problems such as linear degradation of offset adjustment caused by enabling the temperature sensor to have an offset adjustment function can be suppressed. Thus, a circuit device is provided that can appropriately reflect the effects of power supply voltage variations and provide temperature compensation for offset adjustment.

[0136] Alternatively, in this embodiment, the correction voltage output circuit may include an operational amplifier, the first input terminal of which is input with a power compensation voltage that varies according to the power supply voltage, the second input terminal of which is input with an offset adjustment voltage, and the operational amplifier outputs a correction voltage from its output terminal.

[0137] Therefore, a correction voltage reflecting the power supply voltage and offset adjustment voltage can be output from the output terminal of the operational amplifier.

[0138] Alternatively, in this embodiment, the correction voltage output circuit may include a first resistor and a second resistor connected in series between the input node of the power supply voltage and the node of the output terminal, and the power supply compensation voltage from the connection node of the first resistor and the second resistor is provided to the first input terminal of the operational amplifier.

[0139] Therefore, the voltage divided by the first and second resistors can be used as a power supply compensation voltage and input to the first input terminal of the operational amplifier.

[0140] Alternatively, in this embodiment, the resistance ratio of the first resistor to the second resistor may be variable, or at least one of the resistance values ​​of the first resistor and the second resistor may be variable.

[0141] Therefore, the power supply voltage and offset adjustment voltage can be variably controlled to reflect the correction voltage by means of the resistance ratio or resistance value of the first resistor and the second resistor.

[0142] Alternatively, in this embodiment, the offset adjustment circuit may be a circuit that converts the offset adjustment data D / A into an offset adjustment voltage using an R-2R trapezoidal configuration.

[0143] Thus, the offset adjustment circuit of the D / A conversion circuit based on the R-2R trapezoidal method can improve the linearity of offset adjustment compared to the structure that enables the temperature sensor to have offset adjustment function.

[0144] Alternatively, in this embodiment, the correction circuit may include an operational amplifier, the first input terminal of which is input with a compensation voltage that varies according to the correction voltage, the second input terminal of which is input with a temperature detection voltage, and the operational amplifier outputting the corrected temperature detection voltage from its output terminal.

[0145] Therefore, the temperature detection voltage of the temperature sensor can be output from the output terminal of the operational amplifier so that it reflects the corrected temperature detection voltage.

[0146] Alternatively, in this embodiment, the correction circuit may include a first resistor and a second resistor connected in series between the input node of the correction voltage and the node of the output terminal, and the compensation voltage from the connection node of the first resistor and the second resistor is provided to the first input terminal of the operational amplifier.

[0147] Therefore, the voltage divided by the resistors based on the first and second resistors can be input as a compensation voltage to the first input terminal of the operational amplifier. Thus, the first input terminal of the operational amplifier receives a compensation voltage that varies according to the correction voltage, and the second input terminal of the operational amplifier receives a temperature detection voltage.

[0148] In addition, in this embodiment, when the temperature difference between the temperature detected by the temperature sensor and the temperature of the oscillator changes due to the fluctuation of the power supply voltage, the correction circuit causes the corrected temperature detection voltage to change by a voltage change corresponding to the temperature difference.

[0149] Therefore, even when the temperature difference between the temperature detected by the temperature sensor and the temperature of the oscillator changes due to variations in the power supply voltage, the temperature detection voltage is corrected by changing the voltage change corresponding to the temperature difference. Thus, the temperature compensation error caused by the temperature difference can be reduced.

[0150] In addition, in this embodiment, the correction voltage output circuit may output a correction voltage that decreases or increases monotonically according to the rise of the power supply voltage, and the amount of voltage change is variable relative to the change of the power supply voltage.

[0151] Therefore, a correction voltage is used for temperature compensation in the temperature detection calibration of the temperature sensor. This correction voltage decreases or increases monotonically as the power supply voltage increases, and the amount of voltage change relative to the change in power supply voltage is variable.

[0152] Furthermore, the oscillator of this embodiment includes: the circuit arrangement described above; and an oscillator.

[0153] Furthermore, while this embodiment has been described in detail above, those skilled in the art will readily understand that various modifications can be made without substantially departing from the new aspects and effects of this disclosure. Therefore, all such modifications are included within the scope of this disclosure. For example, in the specification or drawings, a term described at least once with a different term that is more general or synonymous can be replaced with that different term anywhere in the specification or drawings. Additionally, all combinations of this embodiment and its modifications are also included within the scope of this disclosure. Furthermore, the structure / operation of circuit devices, oscillators, etc., are not limited to those described in this embodiment, and various modifications can be implemented.

Claims

1. A circuit device that operates when supplied with a power supply voltage, characterized in that, The circuit device includes: An oscillating circuit that causes the oscillator to oscillate; A temperature sensor that outputs a temperature detection voltage; An offset adjustment circuit that outputs an offset adjustment voltage for the temperature detection voltage; A correction voltage output circuit, which is input with the power supply voltage and the offset adjustment voltage, outputs a correction voltage that varies according to the power supply voltage and the offset adjustment voltage; A calibration circuit, which receives the temperature detection voltage and the calibration voltage as inputs, and outputs the temperature detection voltage after calibration using the calibration voltage; and A temperature compensation circuit performs temperature compensation on the oscillation frequency of the oscillation circuit based on the corrected temperature detection voltage.

2. The circuit device according to claim 1, characterized in that, The correction voltage output circuit includes an operational amplifier whose first input terminal receives a power compensation voltage that varies according to the power supply voltage, whose second input terminal receives the offset adjustment voltage, and whose output terminal outputs the correction voltage.

3. The circuit device according to claim 2, characterized in that, The correction voltage output circuit includes a first resistor and a second resistor connected in series between the input node of the power supply voltage and the node of the output terminal. The power supply compensation voltage from the connection node of the first resistor and the second resistor is provided to the first input terminal of the operational amplifier.

4. The circuit device according to claim 3, characterized in that, The resistance ratio of the first resistor to the second resistor is variable, or at least one of the resistance values ​​of the first resistor and the second resistor is variable.

5. The circuit device according to claim 1, characterized in that, The offset adjustment circuit is a circuit that converts the offset adjustment data D / A into the offset adjustment voltage using an R-2R trapezoidal configuration.

6. The circuit device according to claim 1, characterized in that, The correction circuit includes an operational amplifier whose first input terminal is input with a compensation voltage that varies according to the correction voltage, whose second input terminal is input with the temperature detection voltage, and whose output terminal outputs the corrected temperature detection voltage.

7. The circuit device according to claim 6, characterized in that, The correction circuit includes a first resistor and a second resistor connected in series between the input node of the correction voltage and the node of the output terminal. The compensation voltage from the connection point of the first resistor and the second resistor is provided to the first input terminal of the operational amplifier.

8. The circuit device according to claim 1, characterized in that, When the temperature difference between the temperature detected by the temperature sensor and the temperature of the oscillator changes due to the fluctuation of the power supply voltage, the correction circuit causes the corrected temperature detection voltage to change by a voltage change corresponding to the temperature difference.

9. The circuit device according to claim 1, characterized in that, The correction voltage output circuit outputs a correction voltage that monotonically decreases or monotonically increases according to the rise of the power supply voltage, and the amount of voltage change is variable relative to the variation of the power supply voltage.

10. An oscillator, characterized in that, The oscillator contains: The circuit device according to any one of claims 1 to 9; and The oscillator.

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