JP2018137512A - Circuit device, oscillator, electronic equipment, moving body and manufacturing method of oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit device capable of performing temperature compensation with high accuracy while suppressing an increase in necessary data amount.SOLUTION: A circuit device includes an oscillation circuit, a temperature detection circuit, and a temperature compensation circuit for compensating for a temperature characteristic of an oscillation frequency of the oscillation circuit based on an output signal from the temperature detection circuit, and the temperature compensation circuit generates a first compensation signal that compensates for the temperature characteristic based on n-th (n is an integer equal to or greater than 2) temperature compensation function while generating a second compensation signal for further compensating for the temperature characteristic remaining without being compensated by the first compensation signal based on one or more second temperature compensation functions.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a circuit device, an oscillator, an electronic device, a moving object, and a method for manufacturing the oscillator.

  A temperature-compensated crystal oscillator (TCXO) includes a crystal resonator and a temperature-compensated oscillation circuit for oscillating the crystal resonator, and the temperature-compensated oscillator circuit oscillates in a predetermined temperature range. High frequency accuracy can be obtained by compensating (temperature compensation) the deviation (frequency deviation) of the oscillation frequency of the child from the desired frequency (target frequency). Such a temperature-compensated crystal oscillator (TCXO) is disclosed in Patent Document 1, for example.

  In Patent Document 1, the difference between the oscillation frequency of the first oscillation circuit connected to the first crystal resonator and the oscillation frequency of the first oscillation circuit at the reference temperature is connected to the second crystal resonator. A first correction value is obtained based on a difference value between the oscillation frequency of the second oscillation circuit and the difference between the oscillation frequency of the second oscillation circuit at the reference temperature, and the first correction value and the frequency measured in advance A crystal oscillator is described in which a second correction value is acquired based on a correction residual that is a difference from the correction value, and a frequency correction value is obtained by adding the first correction value and the second correction value. Yes.

JP 2013-98865 A

  However, in the oscillator described in Patent Document 1, since the correction residual is approximated by a first-order equation or a zero-order equation for each predetermined section, it is not possible to effectively compensate for the mountain-shaped correction residue. Also, when the temperature dependence of the correction residual is approximated by a function that is more complicated than expected, the desired compensation accuracy cannot be obtained, or it is necessary to compensate the correction residual in order to obtain the desired compensation accuracy. There is a risk of causing a significant increase in the amount of data.

  The present invention has been made in view of the above problems, and according to some aspects of the present invention, it is possible to perform temperature compensation with high accuracy while suppressing an increase in necessary data amount. Circuit device, oscillator, and method of manufacturing the oscillator can be provided. In addition, according to some embodiments of the present invention, it is possible to provide an electronic device and a moving body using the oscillator.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
The circuit device according to this application example includes an oscillation circuit, a temperature detection circuit, and a temperature compensation circuit that compensates a temperature characteristic of an oscillation frequency of the oscillation circuit based on an output signal from the temperature detection circuit, The temperature compensation circuit generates a first compensation signal for compensating the temperature characteristic based on an n-th (n is an integer of 2 or more) -order temperature compensation function, and generates one or more second-order temperature compensation functions. Based on this, a second compensation signal that further compensates for the temperature characteristics remaining uncompensated by the first compensation signal is generated.

  According to the circuit device according to this application example, the temperature characteristic of the oscillation frequency of the oscillation circuit is compensated by the first compensation signal generated based on the nth-order temperature compensation function, and one or more second-order temperature compensation functions are obtained. Since the temperature characteristic remaining without being compensated for by the first compensation signal is further compensated by the second compensation signal generated based on the second compensation signal, it is possible to effectively compensate for the mountain-shaped compensation residual and perform temperature compensation with high accuracy. . Further, according to the circuit device according to this application example, even if the temperature dependence of the compensation residual is approximated by a complicated function, the compensation residual is based on one or more secondary temperature compensation functions. Therefore, it is possible to suppress an increase in necessary data amount.

[Application Example 2]
The circuit device according to the application example further includes a storage unit that outputs temperature compensation data to the temperature compensation circuit, wherein the temperature compensation data includes data corresponding to a coefficient value of the nth-order temperature compensation function, and the 2 Data corresponding to the frequency deviation at each vertex of the next temperature compensation function, and data corresponding to the temperature of the intersection of each of the secondary temperature compensation functions and a straight line whose frequency deviation is a constant reference value. But you can.

  The circuit device according to this application example requires a relatively large number of bits for each of the secondary temperature compensation functions by storing data corresponding to vertices and intersections that require a relatively small number of bits. Since it is not necessary to store data corresponding to the coefficient value to be stored, the amount of data to be stored can be reduced, and the size of the storage unit can be reduced.

[Application Example 3]
In the circuit device according to the application example, the temperature detection circuit outputs temperature detection data that is a digital signal as the output signal, and the temperature compensation circuit performs a floating point calculation based on the temperature detection data, and One compensation signal and the second compensation signal may be generated.

  According to the circuit device according to this application example, even when the number of digits of the digital calculation required for generating the first compensation signal and the number of digits of the digital calculation required for generating the second compensation signal are greatly different, the floating-point calculation Thus, it is possible to generate the first compensation signal and the second compensation signal with high accuracy while ensuring the effective number of digits as much as possible, so that temperature compensation can be performed with high accuracy.

[Application Example 4]
The circuit device according to the application example further includes a PLL circuit that includes a variable frequency dividing circuit and receives an output signal from the oscillation circuit, and based on the first compensation signal and the second compensation signal, The temperature characteristic may be compensated by controlling the frequency division ratio of the variable frequency dividing circuit.

  According to the circuit device according to this application example, the frequency deviation of the output signal of the PLL circuit is changed by changing the frequency dividing ratio of the variable frequency dividing circuit according to the temperature based on the first compensation signal and the second compensation signal. Therefore, temperature compensation can be performed with high accuracy.

[Application Example 5]
In the circuit device according to the application example, the temperature characteristic may be compensated by controlling an oscillation frequency of the oscillation circuit based on the first compensation signal and the second compensation signal.

  According to the circuit device according to this application example, the frequency deviation of the output signal of the oscillation circuit is reduced by changing the oscillation frequency of the oscillation circuit according to the temperature based on the first compensation signal and the second compensation signal. Therefore, temperature compensation can be performed with high accuracy.

[Application Example 6]
The oscillator according to this application example includes any one of the circuit devices and the vibrator described above.

  According to the oscillator according to this application example, since the circuit device capable of performing temperature compensation with high accuracy while suppressing an increase in necessary data amount is provided, the frequency deviation due to temperature is reduced while reducing the manufacturing cost. A small oscillator can be realized.

[Application Example 7]
An electronic apparatus according to this application example includes the oscillator described above.

[Application Example 8]
The moving body according to this application example includes the oscillator described above.

  According to these application examples, it is possible to realize a more reliable electronic device and moving body including an oscillator with a small frequency deviation.

[Application Example 9]
An oscillator manufacturing method according to this application example includes a temperature characteristic measuring step of measuring an oscillation frequency of an oscillation circuit at a plurality of temperatures and measuring a temperature characteristic of the oscillation frequency, and an n for compensating the temperature characteristic. (N is an integer of 2 or more) a first temperature compensation function calculating step for calculating a next temperature compensation function, and one or more for further compensating the temperature characteristics remaining without being compensated by the nth order temperature compensation function And a second temperature compensation function calculating step of calculating a second-order temperature compensation function.

  According to the method for manufacturing an oscillator according to this application example, the temperature characteristic of the oscillation frequency of the oscillation circuit is compensated based on the calculated n-order temperature compensation function, and the calculated one or more secondary temperature compensation functions are obtained. Based on this, an oscillator capable of effectively compensating for a mountain-shaped compensation residual and performing temperature compensation with high accuracy by further compensating the remaining temperature characteristics without being compensated by the nth-order temperature compensation function. can do. Further, according to the method for manufacturing an oscillator according to this application example, even when the temperature dependency of the compensation residual is approximated by a complicated function, compensation is performed based on one or more second-order temperature compensation functions. By compensating for the residual, it is possible to manufacture an oscillator capable of suppressing an increase in necessary data amount.

The perspective view of the oscillator of this embodiment. Sectional drawing of the oscillator of this embodiment. The bottom view of the oscillator of this embodiment. The functional block diagram of the oscillator of 1st Embodiment. The figure which shows the structural example of a fractional N-PLL circuit. The figure which shows an example of the temperature characteristic of the output signal (temperature detection data) of a temperature detection circuit. The figure which shows an example of the frequency temperature characteristic of the clock signal OSCCLK, and a 1st temperature compensation function. The figure which shows an example of the compensation residual which remains without being compensated with a 1st temperature compensation function, and a 2nd temperature compensation function. The figure which shows an example of 1st temperature compensation data. The figure which shows an example of 2nd temperature compensation data. The figure which shows the relationship between 2nd temperature compensation data and a 2nd temperature compensation function. The flowchart figure which shows an example of the manufacturing method of the oscillator of this embodiment. The figure which shows another example of the frequency temperature characteristic of the clock signal OSCCLK, and a 1st temperature compensation function. The functional block diagram of the oscillator of 2nd Embodiment. 1 is a functional block diagram of an electronic apparatus according to an embodiment. 1 is a diagram illustrating an example of an appearance of an electronic apparatus according to an embodiment. The figure which shows an example of the mobile body of this embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. Also, not all of the configurations described below are essential constituent requirements of the present invention.

1. Oscillator 1-1. First Embodiment [Configuration of Oscillator]
1-3 is a figure which shows an example of the structure of the oscillator 1 of this embodiment. FIG. 1 is a perspective view of the oscillator 1, and FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. FIG. 3 is a bottom view of the oscillator 1.

  The oscillator 1 of the present embodiment is a temperature-compensated oscillator, and includes a circuit device 2, a vibrator 3, a package 4, a lid (lid) 5, and an external terminal (external electrode) 6 as shown in FIGS. It is configured to include. In the present embodiment, the vibrator 3 is a crystal vibrator, but may be, for example, a SAW (Surface Acoustic Wave) resonator, another piezoelectric vibrator, a MEMS (Micro Electro Mechanical Systems) vibrator, or the like. Good. As the substrate material of the vibrator 3, a piezoelectric single crystal such as crystal, lithium tantalate, or lithium niobate, a piezoelectric material such as piezoelectric ceramics such as lead zirconate titanate, or a silicon semiconductor material is used. In addition, as the excitation means of the vibrator 3, one using a piezoelectric effect may be used, or electrostatic driving using a Coulomb force may be used.

  The package 4 accommodates the circuit device 2 and the vibrator 3 in the same space. More specifically, the package 4 is provided with a recess, and the recess 5 is covered with the lid 5 to form the accommodation chamber 7. Two terminals (XG terminal and XD terminal in FIG. 3 described later) of the circuit device 2 and two terminals (excitation electrodes 3a and 3b) of the vibrator 3 are electrically connected to the inside of the package 4 or the surface of the recess. Wiring (not shown) is provided for connection. Further, wiring (not shown) for electrically connecting each terminal of the circuit device 2 and each corresponding external terminal 6 is provided in the package 4 or on the surface of the recess.

  The vibrator 3 has metal excitation electrodes 3a and 3b on the front and back surfaces, respectively, and oscillates at a desired frequency according to the shape and mass of the vibrator 3 including the excitation electrodes 3a and 3b.

  As shown in FIG. 3, the oscillator 1 has an external terminal VCC as a power supply terminal, an external terminal GND as a ground terminal, an external terminal OE as an input terminal, and an external terminal OUT as an output terminal on the bottom surface (the back surface of the package 4). The four external terminals 6 are provided. A power supply voltage is supplied to the external terminal VCC, and the external terminal GND is grounded.

  FIG. 4 is a functional block diagram of the oscillator 1 according to the first embodiment. As shown in FIG. 4, the oscillator 1 of the first embodiment includes a circuit device 2 and a vibrator 3. The circuit device 2 is provided with a VCC terminal as a power supply terminal, a GND terminal as a ground terminal, an OE terminal as an input terminal, an OUT terminal as an output terminal, and an XG terminal and an XD terminal as connection terminals with the vibrator 3. ing. The VCC terminal, the GND terminal, the OE terminal, and the OUT terminal are exposed on the surface of the circuit device 2 and are connected to the external terminals VCC, GND, OE, and OUT of the oscillator 1 provided in the package 4, respectively. The XG terminal is connected to one end (one terminal) of the vibrator 3 and the XD terminal is connected to the other end (the other terminal) of the vibrator 3.

  In the present embodiment, the circuit device 2 includes an oscillation circuit 21, a fractional N-PLL circuit 22, an output circuit 23, a temperature detection circuit 24, a temperature compensation circuit 25, a storage unit 26, and a serial interface (I / F) circuit 27. It consists of The circuit device 2 may have a configuration in which some of these elements are omitted or changed, or other elements are added.

  In the present embodiment, the circuit device 2 is configured as a one-chip integrated circuit (IC: Integrated Circuit), but may be configured as a multi-chip integrated circuit (IC), or a part thereof is a discrete component. It may be constituted by.

  The oscillation circuit 21 amplifies the output signal of the vibrator 3 input from the XG terminal of the circuit device 2, and feeds back the amplified signal to the vibrator 3 via the XD terminal of the circuit device 2. And an oscillation signal (clock signal OSCCLK) based on the oscillation of the vibrator 3 is output. For example, the oscillation circuit constituted by the vibrator 3 and the oscillation circuit 21 may be various types of oscillation circuits such as a Pierce oscillation circuit, an inverter type oscillation circuit, a Colpitts oscillation circuit, and a Hartley oscillation circuit.

The fractional N-PLL circuit 22 multiplies the frequency of the oscillation signal (clock signal OSCCLK) output from the oscillation circuit 21 based on the input frequency division ratio. Specifically, the fractional N-PLL circuit 22 generates a clock signal PLLCLK _obtained by multiplying the frequency f _OSCCLK of the clock signal OSCCLK output from the oscillation circuit 21 based on the frequency division ratio input from the temperature compensation circuit 25. . Here, the integer part of the division ratio (integral dividing ratio) N, the fractional part of (fractional dividing ratio) and F / M, the frequency _{f OSCCLK} the clock signal PLLCLK clock signal PLLCLK and the frequency _{f PLLCLK} Between these, the relationship of following Formula (1) is formed.

  FIG. 5 is a diagram illustrating a configuration example of the fractional N-PLL circuit 22. In the example of FIG. 5, the fractional N-PLL circuit 22 includes a phase comparator 221, a charge pump 222, a low-pass filter 223, a voltage controlled oscillation circuit 224, a frequency dividing circuit 225, a clock generation circuit 226, and a delta sigma modulation circuit 227. It consists of

  The phase comparator 221 compares the phase difference between the clock signal OSCCLK output from the oscillation circuit 21 and the clock signal FBCLK output from the frequency dividing circuit 225, and outputs the comparison result as a pulse voltage.

  The charge pump 222 converts the pulse voltage output from the phase comparator 221 into a current, and the low-pass filter 223 smoothes and voltage converts the current output from the charge pump 222.

  The voltage controlled oscillation circuit 224 outputs a clock signal PLLCLK whose frequency changes according to the control voltage using the output voltage of the low-pass filter 223 as a control voltage. The voltage-controlled oscillation circuit 224 is realized by various types of oscillation circuits such as an LC oscillation circuit configured using an inductance element such as a coil and a capacitance element such as a capacitor, and an oscillation circuit using a piezoelectric vibrator such as a crystal vibrator. It is feasible.

  The frequency dividing circuit 225 (an example of “variable frequency dividing circuit”) uses the output signal of the delta-sigma modulation circuit 227 as a frequency dividing ratio (integer frequency dividing ratio), and the clock signal PLLCLK output from the voltage controlled oscillation circuit 224 is an integer. The rounded clock signal FBCLK is output.

  The clock generation circuit 226 generates and outputs a clock signal DSMCLK using the clock signal FBCLK. For example, the clock generation circuit 226 may output the clock signal FBCLK as it is as the clock signal DSMCLK, or may output the clock signal DSMCLK obtained by dividing the clock signal FBCLK by an integer.

  The delta sigma modulation circuit 227 performs delta sigma modulation that integrates and quantizes the frequency division ratio N + F / M input from the temperature compensation circuit 25 in synchronization with the clock signal DSMCLK output from the clock generation circuit 226.

The output signal of the delta sigma modulation circuit 227 is input to the frequency dividing circuit 225. In the output signal of the delta-sigma modulation circuit 227, a plurality of integer division ratios in a range in the vicinity of the integer division ratio N change in time series, and the time average value thereof matches N + F / M. Then, in the steady state phase is synchronized in phase and the clock signal FBCLK clock signal OSCCLK, satisfy the relationship of formula (1) and the frequency _{f OSCCLK} frequency _{f PLLCLK} and clock signal OSCCLK of the clock signal PLLCLK, thereby the clock signal PLLCLK frequency f _PLLCLK approaches the target frequency. In this embodiment, the frequency division ratio N + F / M is input to the delta sigma modulation circuit 227. For example, the delta sigma modulation circuit 227 performs delta sigma modulation on the fractional frequency division ratio F / M, and delta sigma The output signal of the modulation circuit 227 and the integer frequency division ratio N may be added and subtracted and input to the frequency dividing circuit 225.

  Returning to FIG. 4, the output circuit 23 operates when the control signal (output enable signal) input from the external terminal OE of the oscillator 1 (the OE terminal of the circuit device 2) is active (for example, high level). A clock signal CLK in which the amplitude of the clock signal PLLCLK output from the N-PLL circuit 22 is adjusted to a desired level is generated. The clock signal CLK generated by the output circuit 23 is output to the outside of the oscillator 1 via the OUT terminal of the circuit device 2 and the external terminal OUT of the oscillator 1.

  The temperature detection circuit 24 detects the temperature and outputs a signal corresponding to the detected temperature. In the present embodiment, the temperature detection circuit 24 outputs temperature detection data DT that is a digital signal as a signal corresponding to the detected temperature. For example, the temperature detection circuit 24 uses a temperature sensor (for example, a thermistor or a temperature sensor using the temperature characteristics of a band gap reference circuit) whose voltage changes according to the temperature, and an output signal of the temperature sensor as a temperature. It may be configured to include an A / D (Analog to Digital) converter that converts the detection data DT, and an oscillating unit whose oscillating frequency changes according to temperature and an oscillating frequency of the oscillating unit are measured. A measurement unit that outputs temperature detection data DT corresponding to the measurement result may be included. In the latter case, for example, the temperature detection circuit 24 may measure the oscillation frequency difference between the two crystal resonators and output temperature detection data DT corresponding to the measurement result.

  FIG. 6 is a diagram illustrating an example of the temperature characteristic of the output signal (temperature detection data DT) of the temperature detection circuit 24. In FIG. 6, the horizontal axis represents temperature (unit: ° C.), and the vertical axis represents temperature detection data DT. In the example of FIG. 6, the temperature detection data DT has a 10-bit digital value (0 to 1023), and at least in the operation guaranteed temperature range of the oscillator 1 (for example, −40 ° C. to + 85 ° C.) It changes in a staircase pattern at an almost constant rate. That is, in the example of FIG. 6, the temperature detection circuit 24 outputs temperature detection data DT having a 10-bit resolution.

The temperature compensation circuit 25 compensates for the temperature characteristic (frequency temperature characteristic) of the oscillation frequency (frequency f _OSCCLK of the clock signal OSCCLK) of the oscillation circuit 21 based on the output signal (temperature detection data DT) from the temperature detection circuit 24. . Specifically, the temperature compensation circuit 25 divides the frequency of the fractional N-PLL circuit 22 according to the temperature detection data DT so that the frequency temperature characteristic of the clock signal OSCCLK is compensated based on the temperature detection data DT. The ratio N + F / M is set to be variable.

The oscillation frequency of the oscillation circuit 21 (frequency _{f OSCCLK} clock signal OSCCLK) has a temperature characteristic due to the temperature characteristics of the vibrator 3, and the like. Therefore, the temperature compensation circuit 25 compensates the temperature characteristic (frequency temperature characteristic) of the frequency f _OSCCLK of the clock signal OSCCLK using the first temperature compensation function fcomp1 expressed by the following equation (2). In the formula (2), T ₀ is a reference temperature (for example, + 25 ° C.).

  The first temperature compensation function fcomp1 represented by the equation (2) is an nth-order temperature obtained by approximating the frequency-temperature characteristic of the clock signal OSCCLK or its inverse characteristic by n (n is an integer of 2 or more) using the temperature T as a variable. It is a compensation function.

FIG. 7 is a diagram illustrating an example of the frequency temperature characteristic of the clock signal OSCCLK and the first temperature compensation function fcomp1. In FIG. 7, the horizontal axis represents temperature (unit: ° C.), and the vertical axis represents frequency deviation (unit: ppm) based on the frequency at the reference temperature T ₀ . The solid line indicates the frequency temperature characteristic of the clock signal OSCCLK, and the alternate long and short dash line indicates the first temperature compensation function fcomp1. In the example of FIG. 7, the frequency deviation (difference from the target frequency) of the clock signal OSCCLK changes in a substantially cubic curve with respect to the temperature with the reference temperature + 25 ° C. as the inflection point. Is in a range of about ± 20 ppm in a temperature range (operation guaranteed temperature range) (eg, −40 ° C. to + 85 ° C.). The first temperature compensation function fcomp1 is obtained by approximating the inverse characteristic of the frequency temperature characteristic of the clock signal OSCCLK by an nth order expression (for example, a fifth order expression).

  The frequency temperature characteristic (frequency deviation) of the clock signal OSCCLK is compensated by using the first temperature compensation function fcomp1, but part of it remains uncompensated. Therefore, in the present embodiment, the temperature compensation circuit 25 further compensates the frequency temperature characteristic (compensation residual) that remains without compensation by using a second temperature compensation function fcomp2 expressed by the following equation (3). .

In Expression (3), α ₁ , α ₂ ,..., Α _m are m (m is an integer of 1 or more) temperatures at which the compensation residual (frequency deviation) is a reference value, and are quadratic functions. b _i (T−α _i ) (T−α _{i + 1} ) is a quadratic function that approximates the compensation residual at temperatures α _{i to} α _{i + 1} or its inverse characteristic by a quadratic expression. The reference value of the compensation residual (frequency deviation) is a frequency deviation value (eg, 0) at the reference temperature T ₀ (eg, + 25 ° C.). The second temperature compensation function fcomp2 expressed by the equation (3) is obtained by synthesizing m second-order temperature compensation functions approximating the compensation residual or its inverse characteristic for each of the m temperature ranges.

FIG. 8 is a diagram illustrating an example of frequency temperature characteristics (compensation residual) that remain without being compensated by the first temperature compensation function fcomp1 and the second temperature compensation function fcomp2. In FIG. 8, the horizontal axis represents temperature (unit: ° C.), and the vertical axis represents frequency deviation (unit: ppm). The solid line indicates the compensation residual, and the alternate long and short dash line indicates the second temperature compensation function fcomp2. In the example of FIG. 8, the compensation residual is in a range of about ± 0.1 ppm in the guaranteed operating temperature range of the oscillator 1 (for example, −40 ° C. to + 85 ° C.). The curve indicating the compensation residual intersects with a straight line having a constant frequency deviation (a straight line with a frequency deviation of 0 in FIG. 8) at eleven temperatures α _{1 to} α ₁₁ , and the second temperature compensation. The function fcomp2 is obtained by approximating the inverse characteristic of the compensation residual with a quadratic expression in each temperature range of temperatures α _{i to} α _{i + 1} (i = 1 to 10).

  The temperature compensation circuit 25 divides the frequency of the fractional N-PLL circuit 22 according to the temperature detection data DT so as to realize a temperature compensation function obtained by adding the first temperature compensation function fcomp1 and the second temperature compensation function fcomp2. The ratio N + F / M is set to be variable. Specifically, as illustrated in FIG. 4, the temperature compensation circuit 25 includes a first compensation signal generation circuit 251, a second compensation signal generation circuit 252, and an addition circuit 253.

The first compensation signal generation circuit 251 generates a first compensation signal C1 that compensates for the temperature characteristic of the oscillation frequency of the oscillation circuit 21 based on the first temperature compensation function fcomp1 (nth-order temperature compensation function). In the present embodiment, the first compensation signal generation circuit 251 performs a floating point calculation based on the temperature detection data DT using the first temperature compensation data stored in advance in the storage unit 26, and generates the first compensation signal C1. Generate. FIG. 9 shows an example of the first temperature compensation data stored in the storage unit 26. First temperature compensation data is data corresponding to the coefficient values _a n ~a ₀ of the first temperature compensation function fcomp1 (n following temperature compensation function), as shown in FIG. 9, the coefficient values _a n ~a ₀ It may be itself. The first compensation signal C1, for example, the frequency division ratio reference divider ratio previously set as the fractional N-PLL circuit 22 at a reference temperature _{T 0 (N + F / M} ) difference values for ₀ (change amount) with a signal indicating the Yes, at each temperature, it has a value proportional to the first temperature compensation function fcomp1.

The first compensation signal generation circuit 251 uses, for example, the coefficient values a _{n to} a ₀ for the temperature T corresponding to the temperature detection data DT, and the first temperature compensation function fcomp1 at the temperature T according to Equation (2). Is calculated to generate the first compensation signal C1.

The second compensation signal generation circuit 252 is not compensated by the first compensation signal C1 generated by the first compensation signal generation circuit 251 based on the second temperature compensation function fcomp2 (m second-order temperature compensation functions). A second compensation signal C2 for further compensating for the temperature characteristic (compensation residual) of the oscillation frequency of the remaining oscillation circuit 21 is generated. In the present embodiment, the second compensation signal generation circuit 252 performs a floating point calculation based on the temperature detection data DT using the second temperature compensation data stored in advance in the storage unit 26, and generates the second compensation signal C2. Generate. FIG. 10 shows an example of the second temperature compensation data stored in the storage unit 26. FIG. 11 shows the relationship between the second temperature compensation data of FIG. 10 and the second temperature compensation function fcomp2. The second temperature compensation data includes frequency deviations β _{1 to} β _{m at} the vertices (black circles in FIG. 11) of the m second-order temperature compensation functions constituting the second temperature compensation function fcomp2 (the one-dot chain line in FIG. 11). The intersection point (white circle in FIG. 11) of the data corresponding to ₋₁ and each of the m secondary temperature compensation functions and a straight line having a constant frequency deviation (a straight line having a frequency deviation of 0 in FIG. 11) of a data corresponding to the temperature alpha ₁ to? _m, as shown in FIG. 10, or may be the frequency deviation β ₁ ~β _m-1 itself and temperature alpha ₁ to? _m. The second compensation signal C2 is, for example, a signal indicating a difference value (change amount) with respect to the reference frequency division ratio (N + F / M) ₀ of the fractional N-PLL circuit 22, and at each temperature, a second temperature compensation function fcomp2 is obtained. Has a proportional value.

For example, the second compensation signal generation circuit 252 obtains temperatures α _i and α _{i + 1} satisfying α _i ≦ T ≦ α _{i + 1} among the temperatures α _{1 to} α _m with respect to the temperature T corresponding to the temperature detection data DT. Then, using the temperatures α _i and α _{i + 1} and the frequency deviation β _i , the coefficient value b _i of the second-order temperature compensation function at which the temperatures of the intersections are α _i and α _{i + 1} is calculated by the following equation (4). Then, the second compensation signal generation circuit 252 calculates the value of the second temperature compensation function fcomp2 at the temperature T by Expression (3), and generates the second compensation signal C2.

Here, in order to ensure sufficient temperature compensation accuracy, when the first compensation signal generation circuit 251 and the second compensation signal generation circuit 252 perform a 32-bit floating point calculation, the storage unit 26 temporarily stores the second temperature. When 32-bit second-order coefficient values, first-order coefficient values, and zero-order coefficient values are stored as compensation data for each of the m second-order temperature compensation functions, data of the second temperature compensation data is stored. The amount is 96 mbit. On the other hand, the number of bits of each of the temperatures α _{1 to} α _m of the _m intersections is the same as the number of bits of the temperature detection data DT, for example, 10 bits (see FIG. 6). For example, when further compensating a compensation residual of ± 1 ppm or less (about ± 0.1 ppm in the example of FIG. 8) with a resolution of about 1 ppb, frequency deviations β _{1 to} β _{m−1 of m−1} vertices. For example, the number of bits may be 10 bits. Therefore, in this embodiment, in order to reduce the data amount of the second temperature compensation data and reduce the size of the storage unit 26, the storage unit 26 stores, for example, m intersection points as the second temperature compensation data. Temperatures α _{1 to} α _m and m−1 vertex frequency deviations β _{1 to} β _m−1 are stored. In this case, the data amount of the second temperature compensation data is (20m-10) bits, which is greatly reduced as compared with 96m bits.

The adder circuit 253 generates the first compensation signal generated by the first compensation signal generation circuit 251 at the reference setting value (N + F / M) ₀ of the division ratio of the fractional N-PLL circuit 22 stored in advance in the storage unit 26. C1 and the second compensation signal C2 generated by the second compensation signal generation circuit 252 are added to divide ratio N + F / M of the fractional N-PLL circuit 22 (integer division ratio N and fractional division ratio F / M). Is calculated and output. The output signal (frequency division ratio N + F / M) of the adder circuit 253 is supplied as an output signal of the temperature compensation circuit 25 to the fractional N-PLL circuit 22 (specifically, the delta sigma modulation circuit 227 in FIG. 5). .

Then, the frequency division ratio of the frequency division circuit 225 of the fractional N-PLL circuit 22 is controlled based on the frequency division ratio N + F / M output from the temperature compensation circuit 25, whereby the oscillation frequency (clock) of the oscillation circuit 21 is controlled. The temperature characteristic of the frequency f _OSCCLK ) of the signal OSCCLK is compensated.

  Returning to FIG. 4, the storage unit 26 includes a register 261 and a nonvolatile memory 262, and reads / reads data from / to the register 261 and the nonvolatile memory 262 via a predetermined external terminal of the oscillator 1 or the serial interface circuit 27. The light is configured to be possible. In the present embodiment, since the circuit device 2 connected to the external terminal of the oscillator 1 has only four terminals, VCC, GND, OUT, and OE, the serial interface circuit 27 has, for example, a voltage at the VCC terminal lower than the threshold value. At a high time, a clock signal input from the OE terminal and a data signal input from the OUT terminal may be received to read / write data to / from the register 261 or the nonvolatile memory 262.

The nonvolatile memory 262 is a storage unit for storing various control data, and may be various rewritable nonvolatile memories such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) and a flash memory. However, various non-rewritable nonvolatile memories such as a one-time PROM (One Time Programmable Read Only Memory) may be used. In particular, in this embodiment, the non-volatile memory 262 stores in advance the reference frequency division ratio (N + F / M) ₀ that functions as the first temperature compensation data, the second temperature compensation data, and the frequency setting data. .

  For example, in a manufacturing process (for example, an inspection process) of the oscillator 1, various control data are directly written to the register 261 from the external terminal of the oscillator 1 via the serial interface circuit 27 so that the oscillator 1 satisfies desired characteristics. The adjusted various control data are finally written in the nonvolatile memory 262.

Various control data stored in the nonvolatile memory 262 is transferred from the nonvolatile memory 262 to the register 261 when the circuit device 2 is turned on (when the voltage at the VCC terminal rises from 0 V to a desired voltage). Are held in the register 261. Various control data held in the register 261 is supplied to each circuit. In particular, in the present embodiment, the storage unit 26 (register 261) outputs the first temperature compensation data, the second temperature compensation data, and the reference frequency division ratio (N + F / M) ₀ to the temperature compensation circuit 25.

  The oscillator 1 of the first embodiment configured in this way has a clock signal with a very small frequency deviation (for example, ± tens of ppb or less) in the guaranteed operating temperature range (for example, −40 ° C. to + 85 ° C.). It is possible to output CLK.

[Oscillator manufacturing method]
FIG. 12 is a flowchart showing an example of a method for manufacturing the oscillator according to the present embodiment. The manufacturing method of the oscillator of this embodiment includes steps S10 to S60 shown in FIG. However, in the method for manufacturing an oscillator according to the present embodiment, a part of steps S10 to S60 may be omitted or changed, or another step may be added.

  As shown in FIG. 12, in this embodiment, first, the oscillator 1 including the vibrator 3 and the circuit device 2 is assembled (step S10).

  Next, an inspection device is connected to the oscillator 1 and the power is turned on to the oscillator 1 (step S20). That is, the inspection apparatus supplies a desired power supply voltage to the external terminal VCC of the oscillator 1.

Next, the inspection device writes the reference frequency division ratio (N + F / M) ₀ in the nonvolatile memory 262 of the storage unit 26 of the circuit device 2 (step S30).

Next, the inspection device writes 0 in the register 261 of the storage unit 26 of the circuit device 2 as all the coefficient values a _{n to} a ₀ in the first temperature compensation data (step S40).

Next, the inspection apparatus sets 0 to the register 261 of the storage unit 26 of the circuit device 2 as the temperatures α _{1 to} α _m of all the intersections and the frequency deviations β _{1 to} β _m−1 of the vertexes in the second temperature compensation data. Writing is performed (step S50). By these steps S30 to S50, the oscillation frequency of the oscillation circuit 21 of the circuit device 2 is not temperature compensated.

  Next, the inspection device measures the oscillation frequency of the oscillator 1 (oscillation circuit 21) with respect to a plurality of temperatures included in a desired temperature range, and measures the temperature characteristics of the oscillation frequency (step S60 (“temperature characteristic measurement” An example of “process”)).

  Next, the inspection apparatus calculates a first temperature compensation function fcomp1 (nth-order temperature compensation function) for compensating the temperature characteristic of the oscillation frequency measured in step S60 (step S70 (“first temperature compensation function calculation”). An example of “process”)).

  Next, the inspection apparatus uses a second temperature compensation function fcomp2 (m number of pieces) for further compensating for the temperature characteristic (compensation residual) of the oscillation frequency that is not compensated by the first temperature compensation function fcomp1 calculated in step S70. (Second-order temperature compensation function) is calculated (step S80 (an example of “second temperature compensation function calculation step”)).

  Finally, the inspection apparatus generates first temperature compensation data and second temperature compensation data from the first temperature compensation function fcomp1 calculated in step S70 and the second temperature compensation function fcomp2 calculated in step S80, and the circuit device 2 Writing into the nonvolatile memory 262 of the storage unit 26 (step S90).

  Note that the inspection apparatus may perform step S40 and step S50 as one step.

  Incidentally, as shown in FIG. 13, since the vibrator 3 has a peculiar oscillation mode, the oscillation frequency of the oscillation circuit 21 may change abruptly in a local temperature range (a portion surrounded by a broken line). . Therefore, in the process S40 of FIG. 12, when the oscillation frequency of the oscillation circuit 21 changes abruptly exceeding a desired threshold value, the inspection apparatus ignores the abrupt change and ignores this abrupt change, and the first temperature compensation function fcomp1 (FIG. 13). Is preferably calculated. This steep change in the oscillation frequency remains uncompensated by the temperature compensation based on the first temperature compensation function fcomp1, but in step S50, the second temperature that takes into account the compensation residual due to this steep change in the oscillation frequency. Since the compensation function fcomp2 is calculated, even the oscillator 1 using the vibrator 3 having a specific oscillation mode can perform temperature compensation with high accuracy and improve the yield.

[Function and effect]
As described above, according to the oscillator 1 (circuit device 2) of the first embodiment, the oscillation circuit is generated by the first compensation signal C1 generated based on the first temperature compensation function fcomp1 (nth-order temperature compensation function). 21 is compensated by the second compensation signal C2 generated based on the second temperature compensation function fcomp2 (m second-order temperature compensation functions) without being compensated by the first compensation signal C1. Since the remaining temperature characteristics (compensation residual) are further compensated for, it is possible to effectively compensate for the mountain-shaped compensation residual and perform temperature compensation with high accuracy.

  Further, according to the oscillator 1 (circuit device 2) of the first embodiment, the storage unit 26 stores the frequency deviation at the apex for each of the m second-order temperature compensation functions constituting the second temperature compensation function fcomp2. By storing the second temperature compensation data including the temperature of the intersection, it is not necessary to store a coefficient value that requires a large number of bits, so that the amount of data to be stored can be reduced, and the size of the storage unit 26 Can be reduced. Therefore, it is possible to realize the oscillator 1 having a small frequency deviation due to temperature while reducing the manufacturing cost.

  Furthermore, according to the oscillator 1 (circuit device 2) of the first embodiment, the temperature compensation circuit 25 (the first compensation signal generation circuit 251 and the second compensation signal generation circuit 252) is necessary for generating the first compensation signal C1. Even when the number of digits of the correct digital calculation and the number of digits of the digital calculation necessary for generating the second compensation signal C2 are greatly different, the first compensation signal C1 and the high-precision first compensation signal C1 and Since the second compensation signal C2 can be generated, temperature compensation can be performed with high accuracy.

1-2. Second Embodiment Hereinafter, with respect to the oscillator 1 of the second embodiment, description similar to that of the first embodiment will be omitted or simplified, and contents different from those of the first embodiment will be mainly described. Since the structure of the oscillator 1 of the second embodiment is the same as that of the oscillator 1 (FIGS. 1 to 3) of the first embodiment, illustration and description thereof are omitted. FIG. 14 is a functional block diagram of the oscillator 1 according to the second embodiment. In FIG. 14, the same components as those in FIG. 4 are denoted by the same reference numerals.

  As shown in FIG. 14, in the oscillator 1 according to the second embodiment, the circuit device 2 does not have the fractional N-PLL circuit 22 as compared with the first embodiment (FIG. 4), and the oscillation circuit 21 and the temperature compensation circuit 25. The functions of are different.

  Specifically, the oscillation circuit 21 has a variable capacitance element (varactor) (not shown) and oscillates at a frequency corresponding to the capacitance value of the variable capacitance element. Then, the output circuit 23 generates the clock signal CLK in which the amplitude of the clock signal OSCCLK output from the oscillation circuit 21 is adjusted to a desired level, and the oscillator is connected via the OUT terminal of the circuit device 2 and the external terminal OUT of the oscillator 1. 1 is output to the outside.

  The temperature compensation circuit 25 is a temperature obtained by adding the first temperature compensation function fcomp1 (n-th order temperature compensation function) and the second temperature compensation function fcomp2 (m second-order temperature compensation functions) described in the first embodiment. In order to realize the compensation function, the capacitance value of the variable capacitance element included in the oscillation circuit 21 is variably set according to the temperature detection data DT. Specifically, as shown in FIG. 14, the temperature compensation circuit 25 includes a first compensation signal generation circuit 251, a second compensation signal generation circuit 252, an addition circuit 253, and a D / A (Digital to Analog) conversion circuit 254. It is configured to include.

Similar to the first embodiment, the first compensation signal generation circuit 251 performs a floating point operation based on the temperature detection data DT using the first temperature compensation data stored in advance in the storage unit 26, and performs the first compensation signal. C1 is generated. The first temperature compensation data stored in the storage unit 26 is data corresponding to the coefficient values a _{n to} a ₀ of the first temperature compensation function fcomp1 (nth-order temperature compensation function), as in the first embodiment. . The first compensation signal C1 is, for example, a signal indicating a difference value with respect to a reference capacitance value previously set as the capacitance of the variable capacitor of the oscillator circuit 21 at a reference temperature T ₀ (the change amount), at each temperature, the 1 has a value proportional to the temperature compensation function fcomp1.

Similar to the first embodiment, the second compensation signal generation circuit 252 performs a floating point calculation based on the temperature detection data DT using the second temperature compensation data stored in advance in the storage unit 26, and performs the second compensation signal. C2 is generated. Similarly to the first embodiment, the second temperature compensation data stored in the storage unit 26 includes frequency deviations β ₁ to β at the vertices of m second-order temperature compensation functions constituting the second temperature compensation function fcomp2. Data corresponding to β _m−1 and data corresponding to temperatures α _{1 to} α _m at the intersections of each of the m second-order temperature compensation functions and a straight line having a constant frequency deviation. The second compensation signal C2 is, for example, a signal indicating a difference value (change amount) with respect to the reference capacitance value of the variable capacitance element of the oscillation circuit 21, and has a value proportional to the second temperature compensation function fcomp2 at each temperature.

  The adder circuit 253 adds the first compensation signal C1 and the second compensation signal generation circuit 252 generated by the first compensation signal generation circuit 251 to the reference capacitance value of the variable capacitance element of the oscillation circuit 21 stored in advance in the storage unit 26. Is added to the second compensation signal C2 generated to calculate the capacitance value of the variable capacitance element of the oscillation circuit 21 and output it.

  The D / A conversion circuit 254 converts the output signal (capacitance value) of the addition circuit 253 into a voltage value to be applied to the variable capacitance element and outputs the voltage value. The output signal of the D / A conversion circuit 254 is applied to the variable capacitance element of the oscillation circuit 21 as the output signal of the temperature compensation circuit 25.

Based on the signal output from the temperature compensation circuit 25, the capacitance value of the variable capacitance element of the oscillation circuit 21 is controlled, and thereby the oscillation frequency is controlled, whereby the oscillation frequency (clock signal OSCCLK) of the oscillation circuit 21 is controlled. The temperature characteristic of the frequency f _OSCCLK ) is compensated.

  Other configurations of the oscillator 1 of the second embodiment are the same as those of the first embodiment.

  The oscillator 1 of the second embodiment configured as described above has a very small frequency deviation (for example, ± several) in the guaranteed operating temperature range (for example, −40 ° C. to + 85 ° C.), as in the first embodiment. It is possible to output a clock signal CLK (less than 10 ppb).

1-3. Modifications For example, the oscillator 1 of the first embodiment or the second embodiment is an oscillator (TCXO or the like) having a temperature compensation function, but an oscillator (VC-TCXO (Voltage Controlled Temperature) having a temperature control function and a frequency control function. Compensated Crystal Oscillator)) and the like.

Further, for example, in each of the above-described embodiments, the temperatures α ₁ to α at the intersections of each of the m-th order temperature compensation functions included in the second temperature compensation data and a straight line having a constant frequency deviation. data corresponding to the alpha _m is the value itself of the temperature alpha ₁ to? _m, not limited to this, for example, temperature alpha ₁ to? temperature difference of any one value and m-1 pieces of _m alpha _{i + 1} It may be a value of −α _i (i is an integer of 1 to m−1).

  Further, for example, in the second embodiment described above, the temperature compensation circuit 25 controls the voltage applied to the variable capacitance element of the oscillation circuit 21, but the present invention is not limited to this, and the oscillation circuit 21 includes a plurality of variable capacitance elements. And a plurality of switch elements, and the temperature compensation circuit 25 selects a selection signal (one or more variable capacitors that are electrically connected to the vibrator 3). A signal for controlling on / off of each switch) may be output and supplied to the variable capacitance array.

2. Electronic Device FIG. 15 is a functional block diagram showing an example of the configuration of the electronic device of the present embodiment. FIG. 16 is a diagram illustrating an example of the appearance of a smartphone that is an example of the electronic apparatus of the present embodiment.

  The electronic device 300 according to the present embodiment includes an oscillator 310, a CPU (Central Processing Unit) 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. It is configured. Note that the electronic device of the present embodiment may have a configuration in which some of the components (each unit) in FIG. 15 are omitted or changed, or other components are added.

  The oscillator 310 is a temperature compensated oscillator, and an oscillation signal output from the oscillator 310 is supplied to the CPU 320.

  The CPU 320 is a processing unit that performs various calculation processes and control processes using an oscillation signal supplied from the oscillator 310 as a clock signal in accordance with a program stored in the ROM 340 or the like. Specifically, the CPU 320 performs various processes according to operation signals from the operation unit 330, processes for controlling the communication unit 360 to perform data communication with an external device, and displays various types of information on the display unit 370. The process of transmitting the display signal is performed.

  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 CPU 320.

  The ROM 340 is a storage unit that stores programs, data, and the like for the CPU 320 to perform various calculation processes and control processes.

  The RAM 350 is used as a work area of the CPU 320, and is a storage unit that temporarily stores programs and data read from the ROM 340, data input from the operation unit 330, calculation results executed by the CPU 320 according to various programs, and the like. .

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

  The display unit 370 is a display device configured by an LCD (Liquid Crystal Display) or the like, and displays various types of information based on a display signal input from the CPU 320. The display unit 370 may be provided with a touch panel that functions as the operation unit 330.

  By applying, for example, the oscillator 1 of each of the above-described embodiments as the oscillator 310, the CPU 320 can perform various processes based on a clock signal having a small frequency deviation (high frequency accuracy). Equipment can be realized.

  Various electronic devices can be considered as such an electronic device 300, for example, a personal computer (for example, a mobile personal computer, a laptop personal computer, a tablet personal computer), a mobile terminal such as a smartphone or a mobile phone, Digital cameras, inkjet discharge devices (for example, inkjet printers), storage area network devices such as routers and switches, local area network devices, mobile terminal base station devices, televisions, video cameras, video recorders, car navigation devices, real time Clock devices, pagers, electronic notebooks (including those with communication functions), electronic dictionaries, calculators, electronic game machines, game controllers, word processors, word processors Station, video phone, security TV monitor, electronic binoculars, POS terminal, medical equipment (eg electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish detector, various measurements Examples of such devices include instruments, instruments (for example, vehicles, aircraft, and ship instruments), flight simulators, head mounted displays, motion traces, motion tracking, motion controllers, and PDR (pedestrian orientation measurement).

  As an example of the electronic apparatus 300 of the present embodiment, a transmission apparatus that functions as a terminal base station apparatus that performs wired or wireless communication with a terminal using the above-described oscillator 310 as a reference signal source can be given. By applying, for example, the oscillator 1 according to each of the above-described embodiments as the oscillator 310, an electronic device 300 that is usable for, for example, a communication base station and that is desired to have high frequency accuracy, high performance, and high reliability is realized. It is also possible.

  As another example of the electronic apparatus 300 according to the present embodiment, the communication unit 360 receives an external clock signal, and the CPU 320 (processing unit) converts the external clock signal and the output signal (internal clock signal) of the oscillator 310. And a frequency control unit that controls the frequency of the oscillator 310. This communication device may be, for example, a backbone network device such as stratum 3 or a communication device used for a femtocell.

3. FIG. 17 is a diagram (top view) illustrating an example of a moving object according to the present embodiment. A moving body 400 shown in FIG. 17 includes controllers 420, 430, and 440 that perform various controls such as an oscillator 410, an engine system, a brake system, and a keyless entry system, a battery 450, and a backup battery 460. Note that the mobile body of the present embodiment may have a configuration in which some of the components (each unit) in FIG. 17 are omitted or other components are added.

  The oscillator 410 is a temperature-compensated oscillator, and an oscillation signal output from the oscillator 410 is supplied to the controllers 420, 430, and 440 and used as, for example, a clock signal.

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

  By applying the oscillator 1 of each embodiment described above as the oscillator 410, for example, the controllers 420, 430, and 440 can perform various controls based on an oscillation signal with a small frequency deviation (high frequency accuracy). A highly reliable mobile object can be realized.

  As such a moving body 400, various moving bodies can be considered, and examples thereof include automobiles (including electric automobiles), aircraft such as jets and helicopters, ships, rockets, and artificial satellites.

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

  The above-described embodiments and modifications are merely examples, and the present invention is not limited to these. For example, it is possible to appropriately combine each embodiment and each modification.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Oscillator, 2 ... Circuit apparatus, 3 ... Vibrator, 3a ... Excitation electrode, 3b ... Excitation electrode, 4 ... Package, 5 ... Lid (lid), 6 ... External terminal (external electrode), 7 ... Storage chamber, 21 DESCRIPTION OF SYMBOLS ... Oscillation circuit 22 ... Fractional N-PLL circuit 23 ... Output circuit 24 ... Temperature detection circuit 25 ... Temperature compensation circuit 26 ... Storage part 27 ... Serial interface circuit 221 ... Phase comparator 222 ... Charge pump 223, a low-pass filter, 224, a voltage controlled oscillation circuit, 225, a frequency dividing circuit, 226, a clock generation circuit, 227, a delta-sigma modulation circuit, 251, a first compensation signal generation circuit, 252, a second compensation signal generation circuit, 253 ... adder circuit, 254 ... D / A converter circuit, 261 ... register, 262 ... nonvolatile memory, 300 ... electronic device, 310 ... oscillator, 320 ... CP , 330 ... operation unit, 340 ... ROM, 350 ... RAM, 360 ... communication unit, 370 ... display unit, 400 ... mobile, 410 ... oscillator, 420, 430, 440 ... controller, 450 ... battery, 460 ... backup battery

Claims (9)

An oscillation circuit;
A temperature detection circuit;
A temperature compensation circuit for compensating a temperature characteristic of an oscillation frequency of the oscillation circuit based on an output signal from the temperature detection circuit;
The temperature compensation circuit is:
generating a first compensation signal for compensating the temperature characteristic based on a temperature compensation function of n (n is an integer of 2 or more);
A circuit device that generates a second compensation signal that further compensates for the temperature characteristic remaining uncompensated by the first compensation signal based on one or more secondary temperature compensation functions. A storage unit for outputting temperature compensation data to the temperature compensation circuit;
The temperature compensation data is
Data corresponding to the coefficient value of the nth-order temperature compensation function;
Data corresponding to a frequency deviation at each vertex of the second-order temperature compensation function;
2. The circuit device according to claim 1, comprising: data corresponding to a temperature at an intersection of each of the second-order temperature compensation functions and a straight line having a constant frequency deviation as a reference value. The temperature detection circuit includes:
Output temperature detection data that is a digital signal as the output signal,
The temperature compensation circuit is:
3. The circuit device according to claim 1, wherein floating-point arithmetic is performed based on the temperature detection data to generate the first compensation signal and the second compensation signal. 4. A variable frequency dividing circuit, further comprising a PLL circuit to which an output signal from the oscillation circuit is input;
4. The temperature characteristic is compensated by controlling a frequency division ratio of the variable frequency dividing circuit based on the first compensation signal and the second compensation signal. 5. The circuit device described.   4. The circuit according to claim 1, wherein the temperature characteristic is compensated by controlling an oscillation frequency of the oscillation circuit based on the first compensation signal and the second compensation signal. 5. apparatus.   An oscillator comprising the circuit device according to any one of claims 1 to 5 and a vibrator.   An electronic apparatus comprising the oscillator according to claim 6.   A moving body comprising the oscillator according to claim 6. Measuring the oscillation frequency of the oscillation circuit for a plurality of temperatures, and measuring the temperature characteristics of the oscillation frequency; and
A first temperature compensation function calculating step of calculating an n-th order temperature compensation function (n is an integer of 2 or more) for compensating the temperature characteristics;
A second temperature compensation function calculating step of calculating one or more second-order temperature compensation functions for further compensating the temperature characteristics remaining uncompensated by the n-th order temperature compensation function. Method.