阅读说明：本技术 振荡电路、振荡器、电子设备以及移动体 (Oscillation circuit, oscillator, electronic apparatus, and moving object ) 是由 宇野智博 于 2020-03-24 设计创作，主要内容包括：提供振荡电路、振荡器、电子设备以及移动体,能够降低由于电源电压的变动而使频率精度下降的可能性。振荡电路具有：振荡用电路,其使振子进行振荡,输出振荡信号；温度感测元件,其输出温度检测信号；模拟/数字转换电路,其将所述温度检测信号转换为作为数字信号的温度代码,将电源电压转换为作为数字信号的电源电压代码；以及数字信号处理电路,其根据所述电源电压代码来生成校正代码,根据所述温度代码和所述校正代码,生成对所述振荡信号的频率温度特性进行补偿的温度补偿代码。(Provided are an oscillation circuit, an oscillator, an electronic apparatus, and a mobile object, wherein the possibility of a decrease in frequency accuracy due to a variation in power supply voltage can be reduced. The oscillation circuit includes: an oscillation circuit for oscillating the oscillator and outputting an oscillation signal; a temperature sensing element that outputs a temperature detection signal; an analog/digital conversion circuit that converts the temperature detection signal into a temperature code as a digital signal and converts a power supply voltage into a power supply voltage code as a digital signal; and a digital signal processing circuit that generates a correction code from the power supply voltage code, and generates a temperature compensation code that compensates for a frequency-temperature characteristic of the oscillation signal from the temperature code and the correction code.)

1. An oscillation circuit, wherein the oscillation circuit has:

an oscillation circuit for oscillating the oscillator and outputting an oscillation signal;

a temperature sensing element that outputs a temperature detection signal;

an analog/digital conversion circuit that converts the temperature detection signal into a temperature code as a digital signal and converts a power supply voltage into a power supply voltage code as a digital signal; and

and a digital signal processing circuit that generates a correction code from the power supply voltage code, and generates a temperature compensation code that compensates for a frequency-temperature characteristic of the oscillation signal from the temperature code and the correction code.

2. The oscillation circuit of claim 1, wherein,

the digital signal processing circuit generates the temperature compensation code by a 1 st polynomial having a code obtained by adding the temperature code and the correction code as a variable.

3. The oscillation circuit of claim 1, wherein,

the digital signal processing circuit adds a code obtained by a 1 st polynomial with the temperature code as a variable to the correction code to generate the temperature compensation code.

4. The oscillation circuit according to any one of claims 1 to 3,

the digital signal processing circuit generates the correction code by a 2 nd polynomial with the power supply voltage code as a variable.

5. The oscillation circuit of claim 4, wherein,

the 2 nd polynomial is a higher-order polynomial of 3 or more.

6. The oscillation circuit of claim 2 or 3, wherein,

the digital signal processing circuit generates the correction code by a 2 nd polynomial with the power supply voltage code as a variable,

the digital signal processing circuit corrects the 1 st coefficient value of the 2 nd polynomial in accordance with the temperature code.

7. The oscillation circuit of claim 1, wherein,

the digital signal processing circuit performs digital filtering processing on at least one of the power supply voltage code and the correction code.

8. The oscillation circuit of claim 1, wherein,

the oscillator circuit has an integrated circuit element that contains the digital signal processing circuit and the temperature sensing element.

9. An oscillator, wherein the oscillator has:

the oscillation circuit according to any one of claims 1 to 8; and

the vibrator is provided.

10. An electronic apparatus, wherein the electronic apparatus has:

the oscillator of claim 9; and

and a processing circuit that operates based on an output signal from the oscillator.

11. A movable body, wherein the movable body has:

the oscillator of claim 9; and

and a processing circuit that operates based on an output signal from the oscillator.

Technical Field

The invention relates to an oscillation circuit, an oscillator, an electronic apparatus, and a moving object.

Background

Patent document 1 describes an Oven controlled crystal Oscillator (OCXO) having: a heating element that heats the vibrator; a temperature control circuit for controlling the heating element according to a detection signal of the thermistor; and a temperature compensation circuit that corrects the 1 st order component and the 2 nd order component of the frequency-temperature characteristic of the oscillation signal based on the detection value of the temperature sensor. According to this oven controlled crystal oscillator, the temperature sensor captures a change in the outside air temperature of the oscillator, and the temperature change of the oscillator is estimated, thereby correcting the frequency of the oscillation signal.

Patent document 1: japanese patent laid-open No. 2014-197751

However, in the oven-controlled crystal oscillator described in patent document 1, when a power supply voltage supplied to an Integrated Circuit (IC) provided with a temperature sensor fluctuates, the amount of heat generation of the Integrated Circuit fluctuates, and accordingly, a detection value of the temperature sensor also fluctuates. As a result, the accuracy of temperature compensation may be degraded, and the frequency accuracy may be degraded.

Disclosure of Invention

One embodiment of an oscillation circuit according to the present invention includes: an oscillation circuit for oscillating the oscillator and outputting an oscillation signal; a temperature sensing element that outputs a temperature detection signal; an analog/digital conversion circuit that converts the temperature detection signal into a temperature code as a digital signal and converts a power supply voltage into a power supply voltage code as a digital signal; and a digital signal processing circuit that generates a correction code from the power supply voltage code, and generates a temperature compensation code that compensates for a frequency-temperature characteristic of the oscillation signal from the temperature code and the correction code.

In one aspect of the oscillation circuit, the digital signal processing circuit may generate the temperature compensation code by a 1 st polynomial having a code obtained by adding the temperature code and the correction code as a variable.

In one aspect of the oscillation circuit, the digital signal processing circuit may generate the temperature compensation code by adding a code obtained by a 1 st polynomial with the temperature code as a variable to the correction code.

In one embodiment of the oscillation circuit, the digital signal processing circuit may generate the correction code by a 2 nd polynomial having the power supply voltage code as a variable.

In one embodiment of the oscillation circuit, the 2 nd polynomial may be a higher-order expression of 3 or more.

In one aspect of the oscillation circuit, the digital signal processing circuit may generate the correction code by a 2 nd polynomial having the power supply voltage code as a variable, and the digital signal processing circuit may correct a 1 st-order coefficient value of the 2 nd polynomial based on the temperature code.

In one aspect of the oscillator circuit, the digital signal processing circuit may perform digital filter processing on at least one of the power supply voltage code and the correction code.

One embodiment of the oscillation circuit may further include an integrated circuit element including the digital signal processing circuit and the temperature sensing element.

One embodiment of an oscillator according to the present invention includes: one mode of the oscillation circuit; and the vibrator.

One embodiment of an electronic device of the present invention includes: one mode of the oscillator; and a processing circuit that operates in accordance with an output signal from the oscillator.

One embodiment of a mobile body according to the present invention includes: one mode of the oscillator; and a processing circuit that operates in accordance with an output signal from the oscillator.

Drawings

Fig. 1 is a sectional view of an oscillator according to the present embodiment.

Fig. 2 is a plan view of the oscillator according to the present embodiment.

Fig. 3 is a sectional view showing the vibrator and the lead terminals.

Fig. 4 is a bottom view showing the vibrator and the lead terminals.

Fig. 5 is a functional block diagram of the oscillator according to the present embodiment.

Fig. 6 is a diagram showing an example of the relationship between the outside air temperature, the temperature of the oscillator, and the temperature of the integrated circuit element.

Fig. 7 is a diagram showing an example of the relationship between the power supply voltage and the temperature of the integrated circuit element.

Fig. 8 is a diagram showing an example of a relationship between the power supply voltage and the temperature of the oscillator.

Fig. 9 is a diagram showing an example of the process of generating a frequency division ratio control signal by the digital signal processing circuit of embodiment 1.

FIG. 10 is a graph plotting the 2 nd temperature code against the supply voltage.

Fig. 11 is a graph plotting temperature codes obtained by correcting the 2 nd temperature code using the 2 nd polynomial.

Fig. 12 is a graph plotting temperature codes obtained by correcting the 2 nd temperature code using a polynomial in which the 1 st-order coefficient value of the 2 nd polynomial is corrected in accordance with the outside air temperature.

Fig. 13 is a diagram showing an example of the process of generating a frequency division ratio control signal by the digital signal processing circuit according to embodiment 2.

Fig. 14 is a diagram showing an example of the process of generating a frequency division ratio control signal by the digital signal processing circuit according to embodiment 3.

Fig. 15 is a diagram showing a relationship between a correction code generated based on a power supply voltage code after digital filter processing and a 2 nd temperature code.

Fig. 16 is a diagram showing another example of the process of generating a frequency division ratio control signal by the digital signal processing circuit of embodiment 3.

Fig. 17 is a sectional view of an oscillator according to a modification.

Fig. 18 is a functional block diagram of the electronic device of the present embodiment.

Fig. 19 is a diagram showing an example of the external appearance of the electronic device according to the present embodiment.

Fig. 20 is a diagram showing an example of the mobile body according to the present embodiment.

Description of the reference symbols

1: an oscillator; 2: a vibrator; 3: a vibrating element; 4: an integrated circuit element; 5: an oscillation circuit; 7: a temperature control element; 8: a circuit substrate; 8 f: an upper surface of the circuit substrate; 8 r: a lower surface of the circuit substrate; 10: a housing; 12: a lead terminal; 12 a: a 2 nd connecting part; 12 b: 1 st extension part; 12 c: a 2 nd extension part; 12 d: a 1 st connecting part; 13: a support; 14: a pin terminal; 15: a temperature sensor; 16: an electronic component; 21: a package base; 21 r: a lower surface of the package base; 22: a cover; 23: a seal ring; 24: 1 st connecting terminal; 25: a recess; 26: a 2 nd connection terminal; 30: a base substrate; 30 f: an upper surface of the base substrate; 30 r: a lower surface of the base substrate; 31: a quartz substrate; 32: an external connection terminal; 33: a bonding material; 34: a bottom hole is arranged; 101: a base; 101 b: a flange; 101 f: an upper surface of the base; 101 r: a lower surface of the base; 102: a cap; 102 f: a peripheral portion; 103: a sealing member; 210: a digital signal processing circuit; 220: a temperature control signal generation circuit; 230: an oscillation circuit; 231: a fractional N-PLL circuit; 232: a frequency dividing circuit; 233: an output buffer; 241: a temperature sensor; 242: a selector; 243: an analog/digital conversion circuit; 250: an interface circuit; 260: a storage unit; 261: a ROM; 262: a register group; 270: a regulator; 300: an electronic device; 310: an oscillator; 312: an oscillation circuit; 313: a vibrator; 320: a processing circuit; 330: an operation section; 340: a ROM; 350: a RAM; 360: a communication unit; 370: a display unit; 400: a moving body; 410: an oscillator; 420. 430, 440: a processing circuit; 450: a battery; 460: and a backup battery.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below are not unreasonably restrictive to the contents of the present invention described in the claims. Not all of the structures described below are essential to the present invention.

1. Oscillator

1-1. embodiment 1

1-1-1. oscillator structure

Fig. 1 and 2 are diagrams illustrating an example of the structure of an oscillator 1 according to the present embodiment. Fig. 1 is a sectional view of the oscillator 1, and fig. 2 is a plan view of the oscillator 1. In fig. 2, a perspective view of the cap is used for convenience of explanation. Fig. 3 is a cross-sectional view showing the vibrator and lead terminals housed in the oscillator, and fig. 4 is a bottom view showing the vibrator and lead terminals.

In fig. 1 to 4, for convenience of explanation, 3 axes perpendicular to each other are set as an X axis, a Y axis, and a Z axis, and the Z axis coincides with the thickness direction of the oscillator (in other words, the arrangement direction of the base and the cap joined to the base). In addition, the X axis is along the opposing direction of the lead terminals arranged in two rows, and the Y axis is along the arrangement direction of the lead terminals. In addition, a direction parallel to the X axis is sometimes referred to as an "X axis direction", a direction parallel to the Y axis is sometimes referred to as a "Y axis direction", and a direction parallel to the Z axis is sometimes referred to as a "Z axis direction". In fig. 1 to 4, the wiring pattern and the electrode pads formed inside the case including the base are not shown.

The oscillator 1 of the present embodiment is an oven controlled crystal oscillator (OCXO). As shown in fig. 1 and 2, the oscillator 1 includes: a housing 10 including a base 101 and a cap 102 engaged on the base 101; and a base substrate 30 provided on the lower surface 101r side of the base 101. The housing 10 has a housing space S1 formed by a base 101 and a cap 102, the cap 102 being provided along the outer periphery of the base 101 and engaging on the upper surface of a flange 101b recessed from the upper surface 101f of the base 101.

The housing space S1 in the housing 10 houses: a plurality of pin terminals 14 which penetrate the base 101 and are hermetically sealed by a sealing member 103; a circuit board 8 fixed to an end portion of the pin terminal 14 on the side opposite to the base 101; and a vibrator 2 supported between the circuit board 8 and the base 101 with a gap between the circuit board 8 and the lead terminals 12 connected to the circuit board 8. The temperature control element 7 and the temperature sensor 15 are connected to the base 101 side of the transducer 2 disposed in the housing space S1.

The base 101 is made of, for example, kovar, soft iron, or iron nickel, and has a flange 101b on the outer peripheral portion. The base 101 is provided with a plurality of through holes extending from the upper surface 101f to the lower surface 101r, and conductive pin terminals 14 are inserted into the through holes. The gap between the through hole and the lead terminal 14 is hermetically sealed by a sealing member 103 such as glass. Further, a holder 13 made of an insulator such as glass may be provided on the lower surface 101r of the base 101.

The lead terminal 14 is made of a lead material such as kovar, soft iron, or iron nickel, has one end on the lower surface 101r side of the base 101 and the other end on the accommodation space S1 side, and is erected along the Z-axis direction. The pin terminals 14 are formed in two rows arranged along the Y-axis direction.

The cap 102 is formed by, for example, pressing or drawing a thin metal plate made of copper-nickel-zinc alloy, kovar alloy, soft iron, iron-nickel alloy, or the like into a recessed shape, and has an outer peripheral portion 102f in which an opening portion is bent outward into a flange shape.

The case 10 is configured such that the outer peripheral portion 102f of the cap 102 is placed on the flange 101b of the base 101 so as to overlap therewith, and the portion Q where the flange 101b and the outer peripheral portion 102f overlap is hermetically sealed, thereby forming the storage space S1. The storage space S1 is hermetically sealed in a reduced pressure environment such as a pressure lower than atmospheric pressure or in an inert gas environment such as nitrogen, argon, or helium.

The circuit board 8 may be formed of a printed circuit board, for example. The circuit board 8 has a rectangular shape in plan view in the Z-axis direction, and a through hole is provided at a position facing the upright position of the pin terminal 14 fixed to the base 101. The circuit board 8 is fixed to the pin terminal 14 in a state where the end portion of the pin terminal 14 on the side of the housing space S1 is inserted into the through hole. The circuit board 8 has a lower surface 8r which is a surface on the base 101 side, and an upper surface 8f which is a surface on the opposite side of the lower surface 8 r.

Circuit patterns such as circuit wiring and terminals, not shown, are provided on the upper surface 8f and the lower surface 8r of the circuit board 8. Further, the integrated circuit element 4 for oscillating the vibrator 2, the other electronic components 16, and the like are connected to the circuit pattern on the upper surface 8f of the circuit board 8.

A plurality of lead terminals 12 for supporting the transducer 2 are connected to the circuit pattern on the lower surface 8r of the circuit board 8. The lead terminals 12 are positioned on the outer peripheral side of the circuit board 8 and connected to connection regions R2 arranged along two rows to which the lead terminals 14 are connected, respectively. Lead terminal 12 is connected to transducer 2 at connection region R1 to support transducer 2.

As shown in fig. 3, the vibrator 2 includes a package 20 and the vibration element 3 housed in the package 20. The package 20 has: a package base 21 on which the vibration element 3 is mounted; a cover 22 joined to the package base 21 to provide a housing space S2 for housing the vibration element 3 between the cover 22 and the package base 21; and a frame-shaped seal ring 23 located between the package base 21 and the lid 22, for joining the package base 21 and the lid 22.

The package base 21 has a cavity shape having the recess 25, and has a substantially square rectangular outer shape when viewed from the Z-axis direction in plan view. However, the outer shape of the package base 21 is not limited to a substantially square shape, and may be other rectangular shapes.

The vibrating element 3 is fixed at its outer edge portion to an unillustrated internal terminal provided at a step portion of the package base 21 via a conductive fixing member 29 such as a conductive adhesive. The quartz substrate 31 constituting the vibration element 3 is formed by machining or the like the SC-cut quartz substrate into a substantially circular planar shape, for example. By using the SC-cut quartz substrate, the vibration element 3 with stable temperature characteristics can be obtained with less frequency jump and resistance increase due to parasitic vibration. The shape of the quartz substrate 31 in plan view is not limited to a circular shape, and may be a nonlinear shape such as an elliptical shape or an oval shape, or may be a linear shape such as a triangular shape or a rectangular shape.

The vibration element 3 is not limited to the SC-cut, and for example, an AT-cut or BT-cut quartz resonator, a SAW (Surface Acoustic Wave) resonator, or the like can be used. As the vibration element 3, for example, a piezoelectric vibrator other than a quartz vibrator, an MEMS (Micro Electro Mechanical Systems) vibrator, or the like can be used. As a substrate material of the vibration element 3, a piezoelectric single crystal such as quartz, lithium tantalate, or lithium niobate, a piezoelectric material such as piezoelectric ceramics such as lead zirconate titanate, or a silicon semiconductor material can be used. As the excitation means of the vibration element 3, a means based on a piezoelectric effect may be used, or electrostatic driving based on coulomb force may be used.

The lid 22 is formed in a plate shape, and is joined to an end surface of the package base 21 via a seal ring 23 so as to seal the opening of the recess 25. The seal ring 23 is disposed in a frame shape and is located between the end surface of the package base 21 and the lid 22. The seal ring 23 is made of a metal material, and the package base 21 and the lid 22 are hermetically joined by melting the seal ring 23. By forming the housing space S2 by closing the opening of the recess 25 with the lid 22 in this manner, the vibration element 3 can be housed in the housing space S2.

The storage space S2 of the hermetically sealed package 20 is in a reduced pressure state of, for example, 10Pa or less. This can continue to drive the vibration element 3 stably. However, the environment of the storage space S2 is not particularly limited, and may be filled with an inert gas such as nitrogen or argon to be at atmospheric pressure.

The material of the package base 21 is not particularly limited, but various ceramics such as alumina can be used. In this case, the package base 21 can be manufactured by sintering a laminated body of ceramic sheets. The material constituting the lid 22 is not particularly limited, and may be any material having a linear expansion coefficient similar to that of the material constituting the package base 21. For example, when the ceramic as described above is used as the constituent material of the package base 21, a metal material is preferably used as the constituent material of the lid 22.

A plurality of 1 st connection terminals 24 and a plurality of 2 nd connection terminals 26 that establish electrical conduction with the vibration element 3, for example, through illustrated internal wiring, are provided on the lower surface 21r of the package base 21. Specifically, as shown in fig. 4, four 1 st connection terminals 24 are arranged along the outer edge, and four 2 nd connection terminals 26 are arranged along the outer edge on the opposite side. The number of the 1 st connection terminal 24 and the 2 nd connection terminal 26 is not limited, and may be any number. The 1 st connection terminal 24 and the 2 nd connection terminal 26 can be formed by the following method or the like: a metal wiring material such as tungsten (W) or molybdenum (Mo) is screen-printed on the lower surface 21r of the package base 21, sintered, and plated with nickel (Ni) or gold (Au). Hereinafter, the lower surface 21r of the package base 21 may be referred to as a lower surface 21r of the transducer 2.

The 2 nd connection part 12a of the lead terminal 12 is fixed to the 1 st connection terminal 24 and the 2 nd connection terminal 26 provided on the lower surface 21r of the transducer 2 by electrically connecting them with, for example, a conductive adhesive or soldering. First connection portions 12d of lead terminals 12 are electrically connected to and fixed to lower surface 8r of circuit board 8, and thus transducer 2 is supported by circuit board 8 via lead terminals 12 in a so-called suspended state.

Each lead terminal 12 includes: a 2 nd connecting portion 12a provided at a position including one end; a 1 st connecting portion 12d provided at a position including the other end; and a 1 st extension part 12B and a 2 nd extension part 12c which are located between the 2 nd connection part 12a and the 1 st connection part 12d, and are connected by a 2 nd bent part B2. The 2 nd connecting portion 12a and the 1 st extending portion 12B are connected by the 1 st bent portion B1, and the 1 st connecting portion 12d and the 2 nd extending portion 12c are connected by the 3 rd bent portion B3. In other words, the lead terminal 12 has three bent portions of the 1 st bent portion B1, the 2 nd bent portion B2, and the 3 rd bent portion B3 between the 2 nd connecting portion 12a and the 1 st connecting portion 12d connected to the vibrator 2.

In this way, the lead terminal 12 between the 2 nd connection portion 12a connected to the vibrator 2 and the 1 st connection portion 12d connected to the circuit board 8 is provided with three bending portions of the 1 st bending portion B1, the 2 nd bending portion B2, and the 3 rd bending portion B3, and the vibrator 2 is supported in a so-called suspended state with respect to the circuit board 8, whereby the lead terminal 12 can be easily bent. Further, since lead terminal 12 is configured such that the portion of 2 nd bent portion B2 bulges outward of transducer 2, the rigidity of lead terminal 12 can be further weakened, and the shock or the like transmitted from circuit board 8 to transducer 2 can be more effectively absorbed.

Further, the structure in which 4 lead terminals 12 are disposed on the 1 st connection terminal 24 side and 4 lead terminals 12 are disposed on the 2 nd connection terminal 26 side of the transducer 2 has been described, but the number of lead terminals 12 is not limited, and any number may be used as long as the transducer 2 can be supported.

The temperature control element 7 is an electronic component connected to the lower surface 21r of the vibrator 2 and controlling the temperature of the vibrator 2. In the present embodiment, the temperature control element 7 is a heat generating element such as a power transistor, and heats the oscillator 2 to maintain the temperature of the oscillation element 3 of the oscillator 2 substantially constant. By maintaining the temperature of the vibration element 3 substantially constant, an excellent frequency stability can be maintained.

The temperature sensor 15 is disposed in the vicinity of the vibrator 2 and detects the temperature of the vibrator 2. In particular, in the present embodiment, the temperature sensor 15 is disposed so as to be in contact with the outer surface of the vibrator 2. As the temperature sensor 15, for example, a thermistor, a platinum resistor, or the like can be used.

The base substrate 30 may be formed of a printed substrate, for example. The base substrate 30 has an upper surface 30f on the base 101 side and a lower surface 30r which is a surface on the opposite side from the upper surface. The base substrate 30 has a bottom hole 34 in an upper surface 30f facing a standing position of the pin terminal 14 fixed to the base 101. Base board 30 has one end of pin terminal 14 inserted into bottom hole 34, and is connected to pin terminal 14 by bonding material 33 such as solder. Further, a plurality of external connection terminals 32 are provided on the lower surface 30r of the base substrate 30.

1-1-2. functional structure of oscillator

Fig. 5 is a functional block diagram of the oscillator 1 of the present embodiment. As shown in fig. 5, the oscillator 1 of the present embodiment includes a vibrator 2 and an oscillation circuit 5. The oscillation circuit 5 includes an integrated circuit element 4, a temperature control element 7, and a temperature sensor 15.

The temperature control element 7 controls the temperature of the oscillator 2 based on the temperature control signal VHC, and in the present embodiment, is a heat generating element such as a power transistor. The heat generated by the temperature control element 7 is controlled in accordance with a temperature control signal VHC supplied from the integrated circuit element 4. The heat generated by the temperature control element 7 is transferred to the vibrator 2, and the temperature of the vibrator 2 is controlled to be close to a target temperature.

The temperature sensor 15 is a 1 st temperature sensing element that detects temperature and outputs a 1 st temperature detection signal VT1 having a voltage level corresponding to the detected temperature. As described above, the temperature sensor 15 is disposed in the vicinity of the transducer 2 and detects the temperature around the transducer 2. The 1 st temperature detection signal VT1 output from the temperature sensor 15 is supplied to the integrated circuit element 4. The temperature sensor 15 may be a thermistor, a platinum resistor, or the like.

The integrated circuit element 4 includes a digital signal processing circuit 210, a temperature control signal generation circuit 220, an oscillation circuit 230, a fractional N-PLL (Phase Locked Loop) circuit 231, a frequency division circuit 232, an output buffer 233, a temperature sensor 241, a selector 242, an analog/digital conversion circuit 243, an interface circuit 250, a storage unit 260, and a regulator 270.

The oscillation circuit 230 is a circuit as follows: which is electrically connected to both ends of the vibrator 2, amplifies an output signal of the vibrator 2 and feeds back the amplified signal to the vibrator 2, thereby oscillating the vibrator 2 and outputting an oscillation signal. For example, the oscillation circuit 230 may be an oscillation circuit using an inverter as an amplification element, or may be an oscillation circuit using a bipolar transistor as an amplification element.

The fractional N-PLL circuit 231 converts the frequency of the oscillation signal output from the oscillation circuit 230 into a frequency corresponding to the division ratio indicated by the division ratio control signal DIVC after delta-sigma modulation.

The frequency dividing circuit 232 divides the frequency of the oscillation signal output from the fractional N-PLL circuit 231.

The output buffer 233 buffers the oscillation signal output from the frequency dividing circuit 232, and outputs the oscillation signal CKO to the outside of the integrated circuit element 4. The oscillation signal CKO is an output signal of the oscillator 1.

The temperature sensor 241 is a 2 nd temperature sensing element that detects temperature and outputs a 2 nd temperature detection signal VT2 having a voltage level corresponding to the detected temperature. For example, the temperature sensor 241 can be implemented by a diode or the like. As described above, the integrated circuit element 4 is bonded to the upper surface 8f of the circuit board 8, and the temperature sensor 241 is provided at a position farther from the vibrator 2 and the temperature control element 7 than the temperature sensor 15. Therefore, the temperature sensor 241 detects the temperature of the position distant from the vibrator 2 and the temperature control element 7. Therefore, when the outside air temperature of the oscillator 1 changes within a predetermined range, the temperature detected by the temperature sensor 15 provided near the temperature control element 7 hardly changes, whereas the temperature detected by the temperature sensor 241 changes within a predetermined range. As described above, the temperature sensor 241 is preferably a temperature sensor for capturing a change in the outside air temperature, and when the outside air temperature changes within a predetermined range, the temperature range detected by the temperature sensor 241 is wide. Therefore, in the present embodiment, as shown in fig. 1, the integrated circuit element 4 including the temperature sensor 241 is provided at a position near the cap 102 that is in contact with the outside air.

The selector 242 selects and outputs any one of the power supply voltage VDD supplied to the oscillator 1, the 2 nd temperature detection signal VT2 output from the temperature sensor 241, and the 1 st temperature detection signal VT1 output from the temperature sensor 15. In the present embodiment, the selector 242 selects and outputs the power supply voltage VDD, the 2 nd temperature detection signal VT2, and the 1 st temperature detection signal VT1 in a time-sharing manner.

The analog/digital conversion circuit 243 converts the power supply voltage VDD, the 2 nd temperature detection signal VT2, and the 1 st temperature detection signal VT1, which are analog signals output from the selector 242 in a time-sharing manner, into a power supply voltage code DVD, a 2 nd temperature code DT2, and a 1 st temperature code DT1, which are digital signals, respectively. The analog/digital conversion circuit 243 may convert the power supply voltage VDD, the 2 nd temperature detection signal VT2, and the 1 st temperature detection signal VT1 into the power supply voltage code DVD, the 2 nd temperature code DT2, and the 1 st temperature code DT1 after converting the voltage level by resistance voltage division or the like.

The digital signal processing circuit 210 generates a temperature control code DHC for controlling the temperature control element 7 based on the target temperature information of the transducer 2 and the 1 st temperature code DT 1. The target temperature information is stored in a ROM (read only Memory) 261 of the storage unit 260. Then, when the power of the oscillator 1 is turned on, the target temperature information is transferred from the ROM 261 to a predetermined register included in the register group 262 and held, and the target temperature information held in the register is supplied to the digital signal processing circuit 210.

In addition, the digital signal processing circuit 210 generates a frequency division ratio control signal DIVC for temperature-compensating the frequency of the oscillation signal from the 2 nd temperature code DT2 and the power supply voltage code DVD. As described above, the division ratio control signal DIVC is supplied to the fractional N-PLL circuit 231, and the fractional N-PLL circuit 231 converts the frequency of the oscillation signal output from the oscillation circuit 230 into a frequency corresponding to the division ratio indicated by the division ratio control signal DIVC. Accordingly, the frequency of the oscillation signal that slightly changes due to the outside air temperature is temperature-compensated, and the oscillation signal output from the fractional N-PLL circuit 231 has a substantially constant frequency regardless of the outside air temperature.

In the present embodiment, the digital signal processing circuit 210 generates a correction code from the power supply voltage code DVD, and generates a temperature compensation code for compensating the frequency-temperature characteristic of the oscillation signal output from the oscillation circuit 230, based on the 2 nd temperature code DT2 and the correction code. Then, the digital signal processing circuit 210 calculates the division ratio of the fractional N-PLL circuit 231 based on the set value of the target frequency and the temperature compensation code stored in the storage unit 260, and generates the division ratio control signal DIVC by delta-sigma modulating the division ratio. For example, in an inspection process when the oscillator 1 is manufactured, the correspondence relationship between the 2 nd temperature code DT2 and the frequency of the oscillation signal is inspected, and temperature compensation information for temperature compensation of the frequency of the oscillation signal is generated based on the correspondence relationship and stored in the ROM 261 of the storage unit 260. When the oscillator 1 is powered on, the temperature compensation information is transferred from the ROM 261 to a predetermined register included in the register group 262 and held, and the digital signal processing circuit 210 generates a temperature compensation code based on the temperature compensation information held in the register, the 2 nd temperature code DT2, and the power supply voltage code DVD.

The digital signal processing circuit 210 may include a digital filter that performs low-pass processing on at least a part of the power supply voltage code DVD, the 2 nd temperature code DT2, and the 1 st temperature code DT1 output from the analog/digital conversion circuit 243 in a time-sharing manner to reduce the intensity of the high-frequency noise signal.

The temperature control signal generation circuit 220 generates and outputs a temperature control signal VHC based on the temperature control code DHC generated by the digital signal processing circuit 210. The temperature control signal VHC is supplied to the temperature control element 7, and the amount of heat generation of the temperature control element 7 is controlled in accordance with the temperature control signal VHC. Thereby, the temperature of the oscillator 2 is controlled to be substantially constant at the target temperature.

The interface circuit 250 is a circuit for performing data communication with an external device, not shown, connected to the oscillator 1. The interface circuit 250 may be, for example, an AND/I²An Interface Circuit corresponding to a C (Inter-Integrated Circuit) bus may be an Interface Circuit corresponding to an SPI (Serial Peripheral Interface) bus.

The storage unit 260 has a ROM 261 which is a nonvolatile memory and a register group 262 which is a volatile memory. In an inspection process when the oscillator 1 is manufactured, the external device writes various data for controlling the operation of each circuit of the oscillator 1 into various registers included in the register group 262 via the interface circuit 250 and adjusts each circuit. Then, the external device stores the determined various optimum data in the ROM 261 via the interface circuit 250. When the oscillator 1 is powered on, various data stored in the ROM 261 are transferred to and held in various registers included in the register group 262, and the various data held in the various registers are supplied to the respective circuits.

The regulator 270 generates a power supply voltage or a reference voltage of each circuit included in the integrated circuit element 4 based on the power supply voltage VDD supplied from the outside of the oscillator 1.

1-1-3 temperature compensation by digital signal processing circuits

In the oscillator 1 of the present embodiment, as described above, the temperature of the oscillator 2 is controlled to be substantially constant at the target temperature in response to the temperature control signal VHC, but the temperature gradient or the like of the housing space S1 changes in response to the temperature of the outside air of the oscillator 1, and an error occurs in the control based on the temperature control signal VHC, and therefore the temperature of the oscillator 2 slightly changes. In this case, since the integrated circuit element 4 is provided in the vicinity of the cap 102 that is in contact with the outside air as described above, the temperature is likely to change in accordance with the outside air temperature.

Fig. 6 is a diagram showing an example of the relationship between the outside air temperature, the temperature of the oscillator 2, and the temperature of the integrated circuit element 4. In fig. 6, the horizontal axis represents the outside air temperature, and the vertical axis represents the temperature of the oscillator 2 or the integrated circuit element 4. The solid line indicates the temperature of the vibrator 2, and the dashed dotted line indicates the temperature of the integrated circuit element 4. In the example of fig. 6, when the outside air temperature rises from the lower limit temperature Tmin to the upper limit temperature Tmax of the range TR ensuring the operation of the oscillator 1, the temperature of the oscillator 2 decreases by Δ T1. Therefore, when the outside air temperature changes, the temperature of the oscillator 2 also changes slightly, and the frequency of the oscillation signal due to the temperature characteristic of the oscillator 2 also changes slightly.

In the example of fig. 6, when the outside air temperature rises from the lower limit temperature Tmin to the upper limit temperature Tmax, the temperature of the integrated circuit element 4 rises by Δ T2. The temperature rise Δ T2 of the integrated circuit element 4 is much larger than the temperature drop Δ T1 of the vibrator 2. That is, the temperature detected by the temperature sensor 241 included in the integrated circuit element 4 changes in a relatively wide range with respect to the change in the outside air temperature. Therefore, the outside air temperature can be estimated from the 2 nd temperature detection signal VT2 output from the temperature sensor 241, the temperature of the oscillator 2 can be estimated from the estimated outside air temperature, and the frequency of the oscillation signal can be temperature-compensated. Therefore, in the present embodiment, the digital signal processing circuit 210 generates the frequency division ratio control signal DIVC based on the temperature compensation information stored in the storage unit 260 and the 2 nd temperature code DT2 converted from the 2 nd temperature detection signal VT2, and can perform temperature compensation on the frequency of the oscillation signal that fluctuates due to the temperature characteristics of the transducer 2 by the fractional N-PLL circuit 231.

However, when the power supply voltage VDD supplied to the oscillator 1 varies, the amount of heat generated by the integrated circuit element 4 varies, and thus the temperature of the integrated circuit element 4 varies. Further, when the amount of heat generation of the integrated circuit element 4 changes, the temperature gradient of the housing space S1 changes, and the temperature of the transducer 2 also changes slightly.

Fig. 7 is a diagram showing an example of the relationship between the power supply voltage VDD and the temperature of the integrated circuit element 4. Fig. 8 is a diagram showing an example of the relationship between the power supply voltage VDD and the temperature of the oscillator 2. Fig. 7 and 8 show the temperatures of the integrated circuit element 4 and the vibrator 2, respectively, in the case where the power supply voltage VDD is increased from 3.0V to 3.6V approximately every 8 minutes when the outside air temperature is +25 ℃. In fig. 7 and 8, the solid line indicates the temperature of integrated circuit element 4 or oscillator 2, and the broken line indicates power supply voltage VDD. As shown in fig. 7, when the power supply voltage VDD increases from 3.0V to 3.6V, the temperature of the integrated circuit element 4 increases by about 1.5 ℃, the heat generation amount of the integrated circuit element 4 increases, and thus the temperature of the oscillator 2 also increases by about 0.12 ℃ as shown in fig. 8.

As described above, the temperature of oscillator 2 changes according to the magnitude of power supply voltage VDD, and the frequency of the oscillation signal changes according to the temperature characteristics of oscillator 2. Therefore, in the present embodiment, the digital signal processing circuit 210 generates the frequency division ratio control signal DIVC from the power supply voltage code DVD converted from the power supply voltage VDD, and thereby the frequency of the oscillation signal that fluctuates due to the fluctuation of the power supply voltage VDD can be temperature-compensated by the fractional N-PLL circuit 231.

Fig. 9 is a diagram showing an example of the generation process of the frequency division ratio control signal DIVC by the digital signal processing circuit 210. In the example of fig. 9, the digital signal processing circuit 210 performs a temperature compensation operation, and generates the temperature compensation code DCMP by the 1 st polynomial expression shown in the following expression (1) with the temperature code DT2X, which is obtained by adding the 2 nd temperature code DT2 and the correction code DTC, as variables. Specifically, the digital signal processing circuit 210 substitutes the temperature code DT2X into the following expression (1) to generate the temperature compensation code DCMP. In the formula (1), the temperature compensation coefficient a_n～a₀The temperature compensation information is stored in the storage unit 260. N is an integer of 1 or more, and is used for accurately adjusting the frequency of the oscillation signalThe ratio is temperature-compensated, and n is preferably 3 or more, that is, the 1 st polynomial is a higher-order expression.

DCMP＝a_n·DT2Xⁿ+a_n-1·DT2X^n-1+…+a₁·DT2X+a₀…(1)

In the example of fig. 9, the digital signal processing circuit 210 performs a power supply voltage correction operation, and generates a correction code DTC by a polynomial 2 shown in the following expression (2) with the power supply voltage code DVD as a variable. Specifically, the digital signal processing circuit 210 substitutes the power supply voltage code DVD into the following expression (2) to generate a correction code DTC. In equation (2), the power supply voltage correction factor b_m～b₀Is stored in the storage unit 260. Further, m is an integer of 1 or more, and m is preferably 3 or more, that is, the 2 nd polynomial is a high-order expression, in order to correct the 2 nd temperature code DT2 which fluctuates depending on the magnitude of the power supply voltage VDD with high accuracy.

DTC＝b_m·DVD^m+b_m-1·DVD^m-1+…+b₁·DVD+b₀…(2)

Fig. 10 is a graph plotting the 2 nd temperature code DT2 when the power supply voltage VDD is 3.0V, 3.1V, 3.2V, 3.3V, 3.4V, 3.5V, 3.6V at an external gas temperature of +25 ℃, -40 ℃, or +85 ℃. In fig. 10, the abscissa represents the power supply voltage VDD, and the ordinate represents the temperature change amount converted from the 2 nd temperature code DT2 with zero value of the 2 nd temperature code DT2 when the power supply voltage is 3.3V. Is a temperature converted from the relative value of the 2 nd temperature code DT2 with reference to the value of the 2 nd temperature code DT2 when the power supply voltage is 3.3V. As shown by the solid line in fig. 10, for example, a polynomial that approximates the relationship between the power supply voltage VDD and the 2 nd temperature code DT2 when the outside air temperature is +25 ℃ corresponds to the 2 nd polynomial.

Fig. 11 is a graph plotting temperature codes obtained by correcting the 2 nd temperature code DT2 using the 2 nd polynomial shown in fig. 10. In fig. 11, the abscissa represents the power supply voltage VDD, and the ordinate represents the temperature change amount obtained by converting the corrected temperature code with zero value of the 2 nd temperature code DT2 when the power supply voltage is 3.3V. In the example of fig. 11, the slope of an approximate straight line that approximates the relationship between the power supply voltage VDD when the outside air temperature is +25 ℃ and the corrected temperature code is substantially zero. On the other hand, the slope of the approximate straight line at the outside air temperature of-40 ℃ is negative, the slope of the approximate straight line at the outside air temperature of +80 ℃ is positive, and the correction accuracy of the 2 nd temperature code DT2 when the power supply voltage VDD is 3.0V or 3.6V is lowered. The difference in the slopes of these approximate straight lines is caused by the difference between the 1 st order coefficient value of the 2 nd polynomial approximating the relationship between the power supply voltage VDD and the 2 nd temperature code DT2 when the external gas temperature is 25 ℃, and the 1 st order coefficient value of the 2 nd polynomial approximating the relationship between the power supply voltage VDD and the 2 nd temperature code DT2 when the external gas temperature is-40 ℃ or +80 ℃.

Therefore, as shown in fig. 9, in the present embodiment, it is preferable that the digital signal processing circuit 210 apply the 1 st order coefficient b of the 2 nd polynomial to the 2 nd temperature code DT2 in the power supply voltage correction operation₁The value of (c) is corrected. For example, the digital signal processing circuit 210 may compare the 1 st order coefficient b stored in the storage unit 260₁Multiplying the temperature gain correction coefficient corresponding to the 2 nd temperature code DT2 in magnitude to thereby obtain the 1 st-order coefficient b₁The value of (c) is corrected. For example, the temperature gain correction coefficient is stored in the storage section 260.

Fig. 12 is a graph plotting a temperature code DT2X obtained by adding a 2 nd temperature code DT2 to a correction code DTC generated using a polynomial in which the 1 st-order coefficient value of the 2 nd polynomial shown in fig. 10 is corrected in accordance with the outside air temperature. In fig. 12, the abscissa represents the power supply voltage VDD, and the ordinate represents the temperature change amount converted from the temperature code DT2X with zero value of the 2 nd temperature code DT2 when the power supply voltage is 3.3V. In the example of fig. 12, compared to fig. 11, the slope of an approximate straight line that approximates the relationship between the power supply voltage VDD and the temperature code DT2X when the outside air temperature is-40 ℃ or +80 ℃ is nearly zero, and it is confirmed that the coefficient b is 1-fold₁The effect of the correction of the value of (c).

In the example of fig. 9, the digital signal processing circuit 210 finally performs a division ratio calculation, calculates the division ratio of the fractional N-PLL circuit 231 from the set value of the target frequency and the temperature compensation code DCMP stored in the storage unit 260, and generates the division ratio control signal DIVC by delta-sigma modulating the division ratio. Then, the fractional N-PLL circuit 231 performs temperature compensation on the frequency of the oscillation signal output from the oscillation circuit 230, thereby obtaining an oscillation signal CKO with high frequency accuracy.

1-1-4. Effect

As described above, in the oscillator 1 according to embodiment 1, in the integrated circuit element 4 included in the oscillation circuit 5, the analog/digital conversion circuit 243 converts the power supply voltage VDD and the 2 nd temperature detection signal VT2 output from the temperature sensor 241 into the power supply voltage code DVD and the 2 nd temperature code DT2, respectively. The digital signal processing circuit 210 generates a correction code DTC from the power supply voltage code DVD, and generates a temperature compensation code DCMP for compensating the frequency-temperature characteristic of the oscillation signal output from the oscillation circuit 230 from the 2 nd temperature code DT2 and the correction code DTC. Specifically, the digital signal processing circuit 210 generates the correction code DTC by the 2 nd polynomial expressed by the expression (2) having the power supply voltage code DVD as a variable, and generates the temperature compensation code DCMP by the 1 st polynomial expressed by the expression (1) having the temperature code DT2X obtained by adding the 2 nd temperature code DT2 and the correction code DTC as a variable. Therefore, according to the oscillator 1 or the oscillator circuit 5 of embodiment 1, even if the 2 nd temperature detection signal VT2 fluctuates due to fluctuation of the amount of heat generation of the integrated circuit element 4 caused by fluctuation of the power supply voltage VDD supplied to the integrated circuit element 4, the 2 nd temperature code DT2 can be corrected in accordance with the power supply voltage code DVD, and temperature compensation can be performed with high accuracy, so that the possibility of frequency accuracy degradation due to fluctuation of the power supply voltage VDD can be reduced.

Further, according to the oscillator 1 or the oscillation circuit 5 of embodiment 1, since the 2 nd temperature code DT2 can be corrected with higher accuracy by setting the 2 nd polynomial expressed by equation (2) to a high-order equation of 3 or more times with the power supply voltage code DVD as a variable, the possibility of the frequency accuracy being lowered due to the fluctuation of the power supply voltage VDD can be further reduced.

In addition, according to the oscillator 1 or the oscillation circuit 5 of embodiment 1, the digital signal processing circuit 210 applies the 1 st order coefficient b of the 2 nd polynomial expressed by the expression (2) according to the 2 nd temperature code DT2₁By correcting the value of (b), even when the relationship between the amount of change in the temperature of integrated circuit element 4 and the amount of change in the temperature of oscillator 2 due to the fluctuation of power supply voltage VDD fluctuates according to the outside air temperature, 2 nd temperature code DT2 can be corrected with high accuracy, and therefore the possibility of frequency accuracy being degraded due to the fluctuation of power supply voltage VDD can be reduced.

Further, according to the oscillator 1 or the oscillation circuit 5 of embodiment 1, the digital signal processing circuit 210 can share an arithmetic unit such as an adder or a multiplier by performing the process of generating the temperature compensation code DCMP in a time-sharing manner with other processes, and therefore, the size of the integrated circuit element 4 can be reduced as compared with the case of performing temperature compensation by an analog circuit.

Further, according to embodiment 1, since various coefficient values used for calculation by the digital signal processing circuit 210 are stored in the storage unit 260, the values can be set to optimum values according to the characteristics of each oscillator 1, and an oscillator 1 or an oscillation circuit 5 with high frequency accuracy can be realized.

1-2 embodiment 2

Hereinafter, the oscillator 1 according to embodiment 2 is given the same reference numerals as those of embodiment 1, and the same description as that of embodiment 1 will be omitted or simplified, and the description thereof will be mainly made of the differences from embodiment 1. The oscillator 1 according to embodiment 2 differs from that according to embodiment 1 in the processing of generating the frequency division ratio control signal DIVC by the digital signal processing circuit 210.

Fig. 13 is a diagram showing an example of the process of generating the frequency division ratio control signal DIVC by the digital signal processing circuit 210 according to embodiment 2. In the example of fig. 13, the digital signal processing circuit 210 adds the code DCMPX obtained by the 1 st polynomial shown in the following expression (3) having the 2 nd temperature code DT2 as a variable to the correction code DTC by the temperature compensation operation, thereby generating the temperature compensation code DCMP. In particular, it relates toThe digital signal processing circuit 210 adds a correction code DTC to the code DCMPX obtained by substituting the 2 nd temperature code DT2 into the following expression (3) to generate a temperature compensation code DCMP. In the formula (3), the temperature compensation coefficient a_n～a₀The temperature compensation information is stored in the storage unit 260. N is an integer of 1 or more, and n is preferably 3 or more, that is, the 1 st polynomial is a high-order expression, in order to accurately compensate the frequency of the oscillation signal for temperature.

DCMPX＝a_n·DT2ⁿ+a_n-1·DT2^n-1+…+a₁·DT2+a₀…(3)

In the example of fig. 13, the digital signal processing circuit 210 performs a power supply voltage correction operation, and generates a correction code DTC by a polynomial 2 shown in the following expression (4) with the power supply voltage code DVD as a variable. Specifically, the digital signal processing circuit 210 substitutes the power supply voltage code DVD into the following equation (4) to generate a correction code DTC. In equation (4), the power supply voltage correction coefficient c_k～c₀Is stored in the storage unit 260. Further, k is an integer of 1 or more, and in order to accurately correct the code DCMPX that varies depending on the magnitude of the power supply voltage VDD, k is preferably 3 or more, that is, the 2 nd polynomial is a high-order expression.

DTC＝c_k·DVD^k+c_k-1，DVD^k-i+…+c₁·DVD+c₀…(4)

In embodiment 2, it is also preferable that the digital signal processing circuit 210 applies the 1 st order coefficient c to the 2 nd polynomial from the 2 nd temperature code DT2 in the power supply voltage correction operation₁The value of (c) is corrected.

In the example of fig. 13, the digital signal processing circuit 210 finally performs a division ratio calculation, calculates the division ratio of the fractional N-PLL circuit 231 from the set value of the target frequency and the temperature compensation code DCMP stored in the storage unit 260, and generates the division ratio control signal DIVC by delta-sigma modulating the division ratio. Then, the fractional N-PLL circuit 231 performs temperature compensation on the frequency of the oscillation signal output from the oscillation circuit 230, thereby obtaining an oscillation signal CKO with high frequency accuracy.

Since the other configurations of the oscillator 1 according to embodiment 2 are the same as those of the oscillator 1 according to embodiment 1, the description thereof is omitted.

As described above, in the oscillator 1 according to embodiment 2, in the integrated circuit element 4 included in the oscillation circuit 5, the analog/digital conversion circuit 243 converts the power supply voltage VDD and the 2 nd temperature detection signal VT2 output from the temperature sensor 241 into the power supply voltage code DVD and the 2 nd temperature code DT2, respectively. The digital signal processing circuit 210 generates a correction code DTC from the power supply voltage code DVD, and generates a temperature compensation code DCMP for compensating the frequency-temperature characteristic of the oscillation signal output from the oscillation circuit 230 from the 2 nd temperature code DT2 and the correction code DTC. Specifically, the digital signal processing circuit 210 generates the correction code DTC by the 2 nd polynomial expressed by equation (4) with the power supply voltage code DVD as a variable, and adds the correction code DTC to the code DCMPX obtained by the 1 st polynomial expressed by equation (3) with the 2 nd temperature code DT2 as a variable, thereby generating the temperature compensation code DCMP. Therefore, according to the oscillator 1 or the oscillator circuit 5 of embodiment 2, even if the 2 nd temperature detection signal VT2 fluctuates due to fluctuation of the amount of heat generation of the integrated circuit element 4 caused by fluctuation of the power supply voltage VDD supplied to the integrated circuit element 4, the 2 nd temperature code DT2 can be corrected in accordance with the power supply voltage code DVD, and temperature compensation can be performed with high accuracy, so that the possibility of frequency accuracy degradation due to fluctuation of the power supply voltage VDD can be reduced.

Further, according to the oscillator 1 or the oscillation circuit 5 of embodiment 2, since the 2 nd temperature code DT2 can be corrected with higher accuracy by setting the 2 nd polynomial expressed by equation (4) to a high-order equation of 3 or more times with the power supply voltage code DVD as a variable, the possibility of the frequency accuracy being lowered due to the fluctuation of the power supply voltage VDD can be further reduced.

In addition, according to the oscillator 1 or the oscillation circuit 5 of embodiment 2, the digital signal processing circuit 210 applies the 1 st order coefficient c of the 2 nd polynomial expression shown in the expression (4) according to the 2 nd temperature code DT2₁Is corrected, thereby, even when the power supply voltage VDD fluctuatesEven when the relationship between the amount of change in the temperature of integrated circuit element 4 and the amount of change in the temperature of oscillator 2 varies depending on the outside air temperature, 2 nd temperature code DT2 can be corrected with high accuracy, and therefore the possibility of frequency accuracy degradation due to variation in power supply voltage VDD can be reduced.

Further, according to the oscillator 1 or the oscillation circuit 5 of embodiment 2, the digital signal processing circuit 210 can share an arithmetic unit such as an adder or a multiplier by performing the process of generating the temperature compensation code DCMP in a time-sharing manner with other processes, and therefore, the size of the integrated circuit element 4 can be reduced as compared with the case of performing temperature compensation by an analog circuit.

Further, according to embodiment 2, since various coefficient values used for calculation by the digital signal processing circuit 210 are stored in the storage unit 260, it is possible to set optimum values according to the characteristics of each oscillator 1, and it is possible to realize an oscillator 1 or an oscillation circuit 5 with high frequency accuracy.

1-3. embodiment 3

Hereinafter, the oscillator 1 according to embodiment 3 is given the same reference numerals as those of embodiment 1, and the same description as that of embodiment 1 will be omitted or simplified, and the description thereof will be mainly made of the differences from embodiment 1. The oscillator 1 according to embodiment 3 differs from that according to embodiment 1 in the processing of generating the frequency division ratio control signal DIVC by the digital signal processing circuit 210. Specifically, the digital signal processing circuit 210 performs digital filter processing on at least one of the power supply voltage code DVD and the correction code DTC.

Fig. 14 is a diagram showing an example of the process of generating the frequency division ratio control signal DIVC by the digital signal processing circuit 210 according to embodiment 3. In the example of fig. 14, the digital signal processing circuit 210 performs digital filtering processing on the power supply voltage code DVD to generate a power supply voltage code DVDF, and performs power supply voltage correction operation on the power supply voltage code DVDF to generate a correction code DTC. The delay time of the digital filtering process is appropriately set in accordance with the delay time from when the power supply voltage VDD changes to when the temperature of the integrated circuit element 4 changes.

Thus, for example, as shown in fig. 15, the 2 nd temperature code DT2 matches the code of the code for which the correction code DTC is determined within a predetermined time t1 after the power supply voltage VDD has changed abruptly, and a temperature code DT2X in which the 2 nd temperature code DT2 has been corrected with high accuracy is obtained. As a result, the temperature compensation code DCMP for highly accurately temperature-compensating the frequency of the oscillation signal is obtained, and the oscillation signal CKO with high frequency accuracy is obtained. Fig. 15 is an example of a case where a temperature change of the integrated circuit element 4 due to a variation in the power supply voltage hardly affects the temperature of the transducer 2, and the delay time of the digital filtering process is appropriately set according to the influence degree.

Fig. 16 is a diagram showing another example of the generation process of the frequency division ratio control signal DIVC by the digital signal processing circuit 210 of embodiment 3. In the example of fig. 16, the digital signal processing circuit 210 performs digital filter processing on a correction code DTC obtained by power supply voltage correction operation on a power supply voltage code DVD, thereby generating a correction code DTCF. Then, the digital signal processing circuit 210 performs a temperature compensation operation on the temperature code DT2X obtained by adding the correction code DTCF and the 2 nd temperature code DT2 to generate the temperature compensation code DCMP. The delay time of the digital filtering process is appropriately set in accordance with the delay time from when the power supply voltage VDD changes to when the temperature of the integrated circuit element 4 changes. In this way, the temperature compensation code DCMP for temperature-compensating the frequency of the oscillation signal with high accuracy can be obtained, and therefore the oscillation signal CKO with high frequency accuracy can be obtained.

In addition, the digital signal processing circuit 210 may perform digital filter processing on both the power supply voltage code DVD and the correction code DTC. In this case, the sum of the delay time of the digital filtering process for the power supply voltage code DVD and the delay time of the digital filtering process for the correction code DTC may be set as appropriate in accordance with the delay time from when the power supply voltage VDD changes to when the temperature of the integrated circuit element 4 changes.

Although not shown and described, the digital signal processing circuit 210 according to embodiment 3 may perform digital filtering processing on at least one of the power supply voltage code DVD and the correction code DTC in the generation processing of the frequency division ratio control signal DIVC performed by the digital signal processing circuit 210 according to embodiment 2 shown in fig. 13.

The oscillator 1 or the oscillation circuit 5 according to embodiment 3 described above provides the same effects as those of embodiment 1 or embodiment 2. In the oscillator 1 according to embodiment 3, since the digital signal processing circuit 210 performs the digital filter processing on at least one of the power supply voltage code DVD and the correction code DTC in the integrated circuit element 4 of the oscillation circuit 5, the error of the correction code DTC caused by the delay time from the change of the power supply voltage VDD to the change of the temperature of the integrated circuit element 4 can be reduced by the delay time of the digital filter processing. Therefore, according to oscillator 1 or oscillation circuit 5 of embodiment 3, the possibility of frequency accuracy degradation due to fluctuations in power supply voltage VDD can be reduced as compared with embodiment 1 or embodiment 2.

1-4. modifications

In each of the above embodiments, the temperature control element 7 and the temperature sensor 15 are provided separately, but the temperature control element 7 and the temperature sensor 15 may be included in 1 integrated circuit element, and the integrated circuit element may be disposed in the vicinity of the vibrator 2. In this case, for example, the temperature control element 7 can be implemented by a resistor and a MOS transistor, and the temperature sensor 15 can be implemented by a diode or the like.

In each of the above embodiments, the integrated circuit element 4 includes 1 temperature sensor 241, but may include a plurality of temperature sensors 241. In this case, for example, the analog/digital conversion circuit 243 may convert the plurality of temperature detection signals output from the plurality of temperature sensors 241 into a plurality of temperature codes, and the digital signal processing circuit 210 may generate the 2 nd temperature code DT2 from the plurality of temperature codes. For example, the digital signal processing circuit 210 may set the average value of the plurality of temperature codes to the 2 nd temperature code DT 2.

In each of the above embodiments, the temperature sensor 241 is included in the integrated circuit element 4, but may be provided outside the integrated circuit element 4 at a position farther from the vibrator 2 and the temperature control element 7 than the temperature sensor 15. In this case, the temperature sensor 241 can be realized by, for example, a thermistor, a platinum resistor, or the like. Fig. 17 is a cross-sectional view of oscillator 1 showing an example in which temperature sensor 241 is provided outside integrated circuit element 4. In the example of fig. 17, the temperature sensor 241 is joined to the upper surface 8f of the circuit board 8 and is provided at a position near the cap 102 that is in contact with the outside air. Therefore, the range in which the temperature detected by the temperature sensor 241 changes with respect to the change in the outside air temperature is widened, and highly accurate temperature compensation is achieved.

In the above embodiments, the analog/digital conversion circuit 243 converts the 1 st temperature detection signal VT1 as an analog signal into the 1 st temperature code DT1 as a digital signal, the digital signal processing circuit 210 generates the temperature control code DHC based on the 1 st temperature code DT1, and the temperature control signal generation circuit 220 converts the temperature control code DHC into the temperature control signal VHC, but the method of generating the temperature control signal VHC is not limited to this. For example, the temperature control signal generation circuit 220 may generate the temperature control signal VHC from the voltage level of the 1 st temperature detection signal VT1 by analog signal processing.

In each of the above embodiments, the frequency division ratio of the fractional-N PLL circuit is controlled by the frequency division ratio control signal DIVC generated by the digital signal processing circuit 210 to perform temperature compensation. For example, the oscillation circuit 230 may have a capacitor array, and perform temperature compensation by selecting a capacitance value of the capacitor array based on the temperature compensation code DCMP generated by the digital signal processing circuit 210. For example, the oscillation circuit 230 may have a variable capacitance element for adjusting the frequency, convert the temperature compensation code DCMP generated by the digital signal processing circuit 210 into an analog signal by a D/a conversion circuit, and control the capacitance value of the variable capacitance element based on the analog signal to perform temperature compensation.

In the above embodiments, the 1 a/d conversion circuit 243 converts the power supply voltage VDD, the 1 st temperature detection signal VT1, and the 2 nd temperature detection signal VT2 into the power supply voltage code DVD, the 1 st temperature code DT1, and the 2 nd temperature code DT2 in a time-sharing manner, respectively, but for example, the a/d conversion circuit may include a plurality of a/d converters that convert the power supply voltage VDD, the 1 st temperature detection signal VT1, and the 2 nd temperature detection signal VT2 into the power supply voltage code DVD, the 1 st temperature code DT1, and the 2 nd temperature code DT2, respectively.

In the above embodiments, the temperature control element 7 is a heat generating element such as a power transistor, but the temperature control element 7 may be a heat absorbing element such as a peltier element depending on the relationship between the target temperature of the oscillator 2 and the outside air temperature as long as the temperature control element can control the temperature of the oscillator 2.

In the above embodiments, the Oscillator 1 has a Temperature control function of adjusting the Temperature of the Oscillator 2 to be near the target Temperature based on the 1 st Temperature code DT1 and a Temperature compensation function based on the 2 nd Temperature code DT2 and the power supply voltage code DVD, but may be an Oscillator having a Temperature compensation function and no Temperature control function, such as a TCXO (Temperature Compensated Crystal Oscillator). The oscillator 1 may be an oscillator having a Temperature compensation function and a frequency control function, such as a Voltage Controlled Temperature Compensated crystal oscillator (VC-TCXO).

2. Electronic device

Fig. 18 is a functional block diagram showing an example of the configuration of the electronic apparatus according to the present embodiment.

The electronic device 300 of the present embodiment includes an oscillator 310, a processing circuit 320, an operation unit 330, a ROM (Read Only Memory) 340, a RAM (Random Access Memory) 350, a communication unit 360, and a display unit 370. The electronic device according to the present embodiment may be configured such that a part of the components shown in fig. 18 is omitted or changed or other components are added.

The oscillator 310 includes an oscillation circuit 312 and a vibrator 313. Oscillator circuit 312 oscillates oscillator 313 to generate an oscillation signal. The oscillation signal is output from an external terminal of the oscillator 310 to the processing circuit 320.

The processing circuit 320 operates based on the output signal from the oscillator 310. For example, the processing circuit 320 performs various calculation processes and control processes using the oscillation signal input from the oscillator 310 as a clock signal in accordance with a program stored in the ROM 340 or the like. Specifically, the processing circuit 320 performs various processes corresponding to an operation signal from the operation unit 330, a process of controlling the communication unit 360 to perform data communication with an external device, a process of transmitting a display signal for displaying various information on the display unit 370, and the like.

The operation unit 330 is an input device including operation keys, button switches, and the like, and outputs an operation signal corresponding to an operation by the user to the processing circuit 320.

The ROM 340 is a storage section as follows: programs and data for the processing circuit 320 to perform various calculation processes and control processes, and the like are stored.

The RAM 350 is a storage section as follows: is used as a work area of the processing circuit 320, and temporarily stores programs and data read from the ROM 340, data input from the operation section 330, calculation results executed by the processing circuit 320 in accordance with various programs, and the like.

The communication unit 360 performs various controls for establishing data communication between the processing circuit 320 and an external device.

The Display unit 370 is a Display device including an LCD (Liquid Crystal Display) or the like, and displays various information in accordance with a Display signal input from the processing circuit 320. A touch panel that functions as the operation unit 330 may be provided on the display unit 370.

By applying the oscillator 1 of each of the above embodiments as the oscillator 310, for example, it is possible to reduce the possibility of a decrease in frequency accuracy due to a variation in power supply voltage, and thus it is possible to realize a highly reliable electronic device.

As such an electronic device 300, various electronic devices are considered, and examples thereof include a personal computer such as a mobile type, a laptop type, a tablet type, or the like, a mobile terminal such as a smartphone or a mobile phone, an ink jet type discharge device such as a digital camera or an ink jet type printer, a storage area network device such as a router or a switch, a local area network device, a device for a mobile terminal base station, a television, a video camera, a video recorder, a car navigation device, a real time clock device, a pager, an electronic organizer, an electronic dictionary, a calculator, an electronic game device, a game controller, a word processor, a workstation, a video phone, a video monitor for theft prevention, an electronic telescope, a POS terminal, an electronic thermometer, a sphygmomanometer, a blood glucose meter, an electrocardiogram measuring device, an ultrasonic diagnostic device, a medical device such as an electronic endoscope, a fish detector, a fish, Various measuring devices, measuring instruments of vehicles, airplanes, ships and the like, flight simulators, head-mounted displays, motion trackers, motion controllers, Pedestrian autonomous navigation (PDR) devices and the like.

Fig. 19 is a diagram showing an example of an external appearance of a smartphone, which is an example of the electronic device 300. A smartphone as the electronic device 300 has buttons as the operation unit 330 and an LCD as the display unit 370. Further, by applying the oscillator 1 according to each of the above embodiments as the oscillator 310 to the smartphone as the electronic device 300, for example, the possibility of a decrease in frequency accuracy due to a variation in power supply voltage can be reduced, and therefore, the electronic device 300 with higher reliability can be realized.

In addition, another example of the electronic device 300 according to the present embodiment is a transmission device that functions as a terminal base station device that communicates with a terminal, for example, by a wired or wireless method, using the oscillator 310 as a reference signal source. By applying the oscillator 1 of each of the above embodiments as the oscillator 310, for example, it is possible to realize the electronic apparatus 300 which can be used in a communication base station or the like and which can expect high frequency accuracy, high performance, and high reliability at a lower cost than ever.

As another example of the electronic device 300 according to the present embodiment, the following communication device may be used: the communication unit 360 receives an external clock signal, and the processing circuit 320 includes a frequency control unit that controls the frequency of the oscillator 310 based on the external clock signal and the output signal of the oscillator 310. The communication device may be, for example, a communication device used in a backbone network device such as Stratum3 or a femtocell.

3. Moving body

Fig. 20 is a diagram showing an example of the mobile body according to the present embodiment. Mobile unit 400 shown in fig. 20 includes oscillator 410, processing circuits 420, 430, and 440, battery 450, and backup battery 460. The mobile unit according to the present embodiment may be configured such that a part of the components shown in fig. 20 is omitted or other components are added.

The oscillator 410 includes an oscillation circuit and a vibrator, not shown, and the oscillation circuit oscillates the vibrator to generate an oscillation signal. The oscillation signal is output from an external terminal of the oscillator 410 to the processing circuits 420, 430, 440, and is used as a clock signal, for example.

The processing circuits 420, 430, and 440 operate based on the output signals from the oscillators, and perform various control processes such as an engine system, a brake system, and a keyless entry system.

The battery 450 supplies power to the oscillator 410 and the processing circuits 420, 430, 440. The backup battery 460 supplies power to the oscillator 410 and the processing circuits 420, 430, 440 when the output voltage of the battery 450 falls below a threshold.

By applying the oscillator 1 of each of the above embodiments as the oscillator 410, for example, it is possible to reduce the possibility of a decrease in frequency accuracy due to a variation in power supply voltage, and thus it is possible to realize a highly reliable mobile body.

As such a movable body 400, various movable bodies are conceivable, and examples thereof include automobiles such as electric automobiles, airplanes such as jet airplanes and helicopters, ships, rockets, artificial satellites, and the like.

The present invention is not limited to the embodiment, and various modifications can be made within the scope of the present invention.

The above embodiment and modification are examples, and are not limited thereto. For example, the embodiments and the modifications can be appropriately combined.

The present invention includes substantially the same structures (for example, structures having the same functions, methods, and results, or structures having the same objects and effects) as those described in the embodiments. The present invention includes a structure in which an immaterial portion of the structure described in the embodiment is replaced. The present invention includes a structure that can achieve the same operational effects or the same objects as the structures described in the embodiments. The present invention includes a configuration in which a known technique is added to the configuration described in the embodiment.