JP2016178606A - Oscillator, electronic apparatus, and mobile body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oscillator capable of achieving a higher frequency accuracy compared with the conventional art.SOLUTION: An oscillator 1 comprises: a temperature compensation circuit 40; an oscillation circuit 10 that receives an output signal of the temperature compensation circuit 40; a non-volatile memory 60; and an addition circuit 50. The non-volatile memory 60 stores a setting value for the temperature compensation circuit 40, and at least one adjustment value 1-N. The addition circuit 50 adds the setting value and any one adjustment value, and outputs the addition result to the temperature compensation circuit 40.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an oscillator, an electronic device, and a moving object.

  In Patent Document 1, the temperature characteristics of a crystal resonator are measured in advance and ranked into a plurality of levels, and each crystal resonator is combined with an IC in which an adjustment value corresponding to the rank is written in a nonvolatile memory. Thus, a temperature compensated crystal oscillator capable of realizing a desired frequency accuracy is described.

JP-A-5-218739

  However, in recent years, even higher frequency accuracy has been required for temperature-compensated oscillators, and due to the characteristics of the measuring instrument used during temperature compensation adjustment and the measurement environment, the frequency deviation during normal operation is subject to temperature compensation adjustment. In some cases, the frequency deviation becomes larger than the time frequency deviation, and the desired frequency accuracy cannot be realized.

  The present invention has been made in view of the above-described problems, and according to some aspects of the present invention, it is possible to provide an oscillator capable of realizing higher frequency accuracy than before. . 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]
An oscillator according to this application example includes a temperature compensation circuit, an oscillation circuit to which an output signal of the temperature compensation circuit is input, a nonvolatile memory, and an adder circuit, and the nonvolatile memory includes the temperature compensation circuit. The set value and at least one adjustment value are stored, and the adder circuit adds the set value and one of the adjustment values and outputs the sum to the temperature compensation circuit.

  The oscillation circuit may be a part or all of various oscillation circuits such as a Pierce oscillation circuit, an inverter type oscillation circuit, a Colpitts oscillation circuit, and a Hartley oscillation circuit.

  According to the oscillator according to this application example, for example, after the temperature compensation circuit setting value is stored in the nonvolatile memory at the time of temperature compensation adjustment, the temperature compensation is performed based on the addition value of the setting value and the adjustment value. Thus, the oscillation frequency can be adjusted to approach the desired frequency. Therefore, according to the oscillator according to this application example, it is possible to achieve higher frequency accuracy than in the past.

[Application Example 2]
The oscillator according to the application example includes a selection circuit, the nonvolatile memory stores a plurality of the adjustment values, the selection circuit selects one of the plurality of adjustment values, and the addition circuit includes The set value and the adjustment value selected by the selection circuit may be added and output to the temperature compensation circuit.

  According to the oscillator according to this application example, for example, after the temperature compensation circuit setting value is stored in the nonvolatile memory at the time of temperature compensation adjustment, one is selected from the plurality of adjustment values, and the setting value is selected. Since temperature compensation can be performed based on the addition value with the adjustment value, the oscillation frequency can be adjusted so as to be closer to a desired frequency than when the adjustment value is one.

[Application Example 3]
In the oscillator according to the application example, the nonvolatile memory may store a selection value, and the selection circuit may select the adjustment value based on the selection value.

  According to this application example, for example, when the oscillator is started, an appropriate adjustment value is automatically selected based on the selection value stored in the nonvolatile memory. Therefore, a signal for selecting the adjustment value is transmitted to the oscillator. Therefore, it is possible to realize an easy-to-use oscillator.

[Application Example 4]
The oscillator according to the application example may include a fuse circuit that outputs a selection value, and the selection circuit may select the adjustment value based on the selection value.

  According to this application example, for example, when the oscillator is started, an appropriate adjustment value is automatically selected based on the selection value output from the fuse circuit. Therefore, a signal for selecting the adjustment value is supplied from the outside of the oscillator. There is no need to input, and an easy-to-use oscillator can be realized.

  Also, when storing the selected value in the non-volatile memory, if the set value and the selected value are assigned to the same address, the set value differs for each oscillator, so it is necessary to read the set value and write the set value and the selected value at the same time. In addition, if the selection value is assigned to a dedicated address, unused bits may be generated and the area of the nonvolatile memory may increase. However, according to this application example, these problems do not occur.

[Application Example 5]
An electronic apparatus according to this application example includes any one of the oscillators described above.

  For example, the electronic device according to this application example controls the frequency of the oscillator based on any of the oscillators described above, a communication unit that receives an external clock signal, and the external clock signal and the output signal of the oscillator. And a frequency control unit that performs communication.

[Application Example 6]
The moving body according to this application example includes any of the oscillators described above.

  According to these application examples, since an oscillator capable of realizing higher frequency accuracy than before is used, for example, it is possible to realize a highly reliable electronic device and moving body.

The perspective view of the oscillator of this embodiment. 2A is a cross-sectional view of the oscillator, and FIG. 2B is a bottom view of the oscillator. The functional block diagram of the oscillator of 1st Embodiment. The timing chart figure which shows an example of mode switching. The flowchart figure which shows an example of the adjustment method of the frequency temperature characteristic of the oscillator of 1st Embodiment. The functional block diagram of the oscillator of 2nd Embodiment. The flowchart figure which shows an example of the adjustment method of the frequency temperature characteristic of the oscillator of 2nd Embodiment. The functional block diagram of the oscillator of a modification. FIG. 3 is a functional block diagram illustrating an example of a configuration of an electronic apparatus according to the 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 and 2 show the structure of the oscillator according to this embodiment. FIG. 1 is a perspective view of the oscillator according to the present embodiment, and FIG. 2A is a cross-sectional view taken along the line AA ′ of FIG. FIG. 2B is a bottom view of the oscillator according to the present embodiment.

  As shown in FIGS. 1 and 2A, the oscillator 1 of this embodiment includes an oscillation integrated circuit (IC) 2, an oscillator 3, a package 4, a lid 5, and an external terminal shown in FIG. (External electrode) 6 and a sealing member 8 are included.

  As the resonator 3, for example, a SAW (Surface Acoustic Wave) resonator, an AT cut crystal resonator, an SC cut crystal resonator, a tuning fork crystal resonator, other piezoelectric resonators, and a MEMS (Micro Electro Mechanical Systems) resonator are used. Etc. can be used. As a 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 can be used. 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 is a container for housing the oscillation IC 2 and the vibrator 3. Specifically, the package 4 is provided with two recesses on the opposing surfaces. By covering one recess with the lid 5, the package 4 becomes the accommodation chamber 7 a and by covering the other recess with the sealing member 8. It becomes the accommodation chamber 7b. The accommodating chamber 7a accommodates the vibrator 3, and the accommodating chamber 7b accommodates the oscillation IC 2. Not shown for electrically connecting two terminals of the oscillation IC 2 (XO terminal and XI terminal in FIG. 3 described later) and two terminals of the vibrator 3 to the inside of the package 4 or the surface of the recess. Wiring is provided. In addition, wiring (not shown) for electrically connecting each terminal of the oscillation IC 2 and each corresponding external terminal 6 is provided inside the package 4 or on the surface of the recess.

  As shown in FIG. 2B, the oscillator 1 of the present embodiment has signals for controlling the external terminal VDD1, which is the power supply terminal 1, the external terminal VSS1, which is the ground terminal, and the oscillation IC 2 on the bottom surface (the back surface of the package 4). Four external terminals 6 including an external terminal VC1 that is an input terminal and an external terminal OUT1 that is an output terminal are provided. A power supply voltage is supplied to the external terminal VDD1, and the external terminal VSS1 is grounded.

FIG. 3 is a functional block diagram of the oscillator according to the first embodiment. As shown in FIG. 3, the oscillator 1 of the first embodiment is an oscillator including an oscillation IC 2 and a vibrator 3, and the oscillation IC 2 and the vibrator 3 are housed in a package 4.

  The oscillation IC 2 is a VDD terminal that is a power supply terminal, a VSS terminal that is a ground terminal, an OUT terminal that is an output terminal, a VC terminal that is a terminal to which a frequency control signal is input, and a connection terminal to the vibrator 3. An XI terminal and an XO terminal are provided. The VDD terminal, the VSS terminal, the OUT terminal, and the VC terminal are exposed on the surface of the oscillation IC 2 (see FIG. 1), and are connected to the external terminals VDD1, VSS1, OUT1, and VC1 provided in the package 4, respectively. Yes. The XI terminal is connected to one end (one terminal) of the vibrator 3, and the XO terminal is connected to the other end (the other terminal) of the vibrator 3.

  In this embodiment, the oscillation IC 2 includes an oscillation circuit 10, an output circuit 20, a frequency adjustment circuit 30, an AFC (Automatic Frequency Control) circuit 32, a temperature compensation circuit 40, a temperature sensor 42, an addition circuit 50, a selection circuit 52, a nonvolatile circuit. The internal memory 60, a register 70, and a serial interface (I / F) circuit 80 are included. Note that the oscillation IC 2 of this embodiment may have a configuration in which some of these elements are omitted or changed, or other elements are added.

  The nonvolatile memory 60 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 the present embodiment, the nonvolatile memory 60 stores set values, N adjustment values 1 to N, and selection values, which are data for controlling the characteristics of the temperature compensation circuit 40. Further, the non-volatile memory 60 also stores data (not shown) for controlling the output circuit 20, the frequency adjustment circuit 30, and the AFC circuit 32, respectively.

  The set value is data for temperature compensation calculated in the temperature compensation adjustment step of the oscillator 1. For example, coefficient values of 0th order, 1st order, 2nd order, 3rd order, etc. according to the frequency temperature characteristics of the vibrator 3. (4th and 5th order coefficient values may be included).

  Adjustment values 1 to N are set value errors caused by the characteristics of the measuring instrument at the time of temperature compensation adjustment, the measurement environment, etc. (errors with respect to the set values where the frequency temperature characteristics during normal operation of the oscillator 1 are within the reference range) ), For example, based on statistical information of setting value errors calculated in the temperature compensation adjustment process for a plurality of oscillators 1 in the past. No value). For example, when statistically it is predicted that the error of the set value is almost determined for almost all the oscillators 1, the adjustment value stored in the nonvolatile memory 60 is one (N = 1). ). Further, for example, when statistically it is predicted that the error of the set value for almost all the oscillators 1 is one of a plurality of values, one adjustment value is stored in the nonvolatile memory 60. (N = 1) may be used. If an oscillator 1 that does not cause a set value error is also predicted, one of the adjustment values 1 to N may be set to zero.

The selection value is data for selecting any one of a plurality of adjustment values 1 to N, and the number of bits is an integer value n satisfying 2 ⁿ⁻¹ <N ≦ 2 ⁿ , for example. It is. Note that when there is only one adjustment value (when N = 1), the selection value is not necessary.

Each data stored in the non-volatile memory 60 is transferred from the non-volatile memory 60 to the register 70 when the oscillation IC 2 is turned on (when the voltage at the VDD terminal rises from 0 V to a desired voltage). Retained.

  In the present embodiment, the oscillation IC 2 can switch between the normal operation mode and the serial I / F mode. In the serial I / F mode, the read to the nonvolatile memory 60 and the register 70 is performed via the serial interface circuit 80. / It is configured to be able to write. In this embodiment, the oscillation IC 2 connected to the external terminal of the oscillator 1 has only four terminals, VDD, VSS, OUT, and VC. Therefore, the normal operation mode and the serial I / O are set according to the voltage level of the VDD terminal. The F mode can be switched.

  FIG. 4 is a timing chart illustrating an example of mode switching. As shown in FIG. 4, in the normal operation mode, the power supply voltage VDD is a voltage VDDL lower than the threshold voltage Vth, and an oscillation signal having an amplitude VDDL is output from the OUT terminal. To switch from the normal operation mode to the serial I / F mode, the voltage at the VC terminal is set to VSS (ground potential), and the voltage at the VDD terminal is higher than VDDL to Vth when the voltage at the VC terminal is VSS. Change to VDDH. The serial interface circuit 80 switches from the normal operation mode to the serial I / F mode according to the voltage at the VC terminal and the voltage at the VDD terminal, and a signal externally input from the VC terminal in the serial I / F mode. Is read as a serial clock signal, and a signal externally input from the OUT terminal is received as a serial data signal (including address information), and the nonvolatile memory 60 or the register 70 is read / written. In the serial I / F mode, the output of the oscillation signal from the output circuit 20 is stopped, and a serial data signal can be input from the OUT terminal. In the present embodiment, the mode is switched to the serial I / F mode by setting the voltage of the VDD terminal to VDDH while the voltage of the VC terminal is set to VSS. For example, the VDD terminal is set with the voltage of the VC terminal set to VDDH. May be switched to the serial I / F mode.

  To switch from the serial I / F mode to the normal operation mode, the voltage at the VDD terminal is changed from VDDH to VDDL. The serial interface circuit 80 switches from the serial I / F mode to the normal operation mode according to the voltage at the VDD terminal. When the mode is switched to the normal operation mode, the output of the oscillation signal from the output circuit 20 is resumed, and an oscillation signal having an amplitude of VDDL is output from the OUT terminal.

  Switching from the normal operation mode to the serial I / F mode is performed, for example, when the oscillator is inspected. When the non-volatile memory 60 is not rewritable, each of the registers 70 holding each data transferred from the non-volatile memory 60 from the external terminal via the serial interface circuit 80 when the oscillator 1 is inspected. Each data is directly written in the bit, and each data adjusted and selected so that the oscillator 1 satisfies a desired characteristic is finally written in the nonvolatile memory 60. When the nonvolatile memory 60 is rewritable, each data may be written to the nonvolatile memory 60 from the external terminal via the serial interface circuit 80 when the oscillator 1 is inspected. However, since writing to the nonvolatile memory 60 generally takes time, when the oscillator 1 is inspected, each data is directly input to each bit of the register 70 from the external terminal via the serial interface circuit 80 in order to shorten the inspection time. Each data that has been written and adjusted / selected may be finally written in the nonvolatile memory 60.

  In FIG. 3, the selection circuit 52 selects and outputs one of the adjustment values 1 to N according to the selection value held in the register 70.

The adder circuit 50 has a set value (set value stored in the non-volatile memory 60) held in the register 70 and an adjustment value (selected in the non-volatile memory 60) selected and output by the selection circuit 52. And an addition result signal (temperature compensation data in which the error of the set value is corrected by the adjustment value) is output to the temperature compensation circuit 40.

  The oscillation circuit 10 is a circuit for causing the vibrator 3 to oscillate, and amplifies the output signal of the vibrator 3 and feeds it back to the vibrator 3. The oscillation circuit 10 is stored in the non-volatile memory 60, and the oscillation stage current is controlled based on the control data transferred to the register 70 when the power is turned on, and outputs an oscillation signal based on the oscillation of the vibrator 3.

  The frequency adjusting circuit 30 generates a voltage corresponding to the control data stored in the nonvolatile memory 60 and transferred to the register 70 when the power is turned on, and functions as a load capacitor of the oscillation circuit 10 (not shown). Is applied to one end. As a result, the oscillation frequency (reference frequency F0) of the oscillation circuit 10 under the condition that the predetermined temperature (for example, 25 ° C.) and the voltage at the VC terminal are the predetermined voltage (for example, VDD / 2) is the desired frequency. Control (fine adjustment) is performed.

  The AFC circuit 32 is stored in the non-volatile memory 60 and its gain is adjusted based on the control data transferred to the register 70 when the power is turned on to generate a voltage corresponding to the voltage at the VC terminal. It is applied to one end of a variable capacitor (not shown) that functions as a load capacitor. Thereby, the oscillation frequency of the oscillation circuit 10 is controlled based on the voltage value of the VC terminal.

  The temperature sensor 42 is a temperature-sensitive element that outputs a signal (for example, a voltage corresponding to the temperature) corresponding to the temperature around the temperature sensor 42. The temperature sensor 42 may have a positive polarity with a higher output voltage as the temperature is higher, or may have a negative polarity with a lower output voltage as the temperature is higher. As the temperature sensor 42, it is desirable that the output voltage changes as linearly as possible with respect to a temperature change in a desired temperature range in which the operation of the oscillator 1 is guaranteed.

  The temperature compensation circuit 40 receives an output signal from the temperature sensor 42, and uses the temperature as a variable, according to the output signal of the addition circuit 50 (temperature compensation data in which an error in the set value is corrected by the adjustment value). 3 is generated and applied to one end of a variable capacitance element (not shown) that functions as a load capacitance of the oscillation circuit 10. As a result, the oscillation frequency of the oscillation circuit 10 is controlled to be substantially constant regardless of the temperature.

  The output circuit 20 receives the oscillation signal output from the oscillation circuit 10, generates an oscillation signal for external output, and outputs it to the outside via the OUT terminal.

  The oscillator 1 according to the first embodiment configured as described above is a voltage control type temperature compensation type that outputs an oscillation signal having a constant frequency according to the voltage of the external terminal VC1 regardless of the temperature in a desired temperature range. It functions as an oscillator (VC-TCXO (Voltage Controlled Temperature Compensated Crystal Oscillator) if the vibrator 3 is a crystal vibrator).

[Adjustment method of frequency temperature characteristics of oscillator]
FIG. 5 is a flowchart illustrating an example of a method for adjusting the frequency temperature characteristic of the oscillator 1 according to the first embodiment. Part of steps S10 to S100 in FIG. 5 may be omitted or changed, or other steps may be added. Moreover, you may change the order of each process suitably in the possible range. Prior to the flowchart of FIG. 5, it is assumed that data for controlling the output circuit 20, the frequency adjustment circuit 30, and the AFC circuit 32 are written in the nonvolatile memory 60, respectively.

In the example of FIG. 5, first, the set value for compensating the frequency temperature characteristic of the vibrator 3 is calculated by swinging the temperature of the oscillator 1 in a desired temperature range (S10). For example, for each of five temperatures in a desired temperature range (for example, −40 ° C. to 85 ° C.), any one of a plurality of set values is written to the register 70 in the serial I / F mode, and normal operation is performed. In the mode, the process of measuring the frequency of the oscillation signal output from the external terminal OUT1 of the oscillator 1 is repeated to obtain the relationship between the set value and the oscillation frequency, and the frequency temperature characteristic of the oscillator 1 is determined based on these relationships. A set value (temperature compensation data) is calculated such that it falls within the reference range (the frequency deviation of the oscillator 1 with respect to the desired frequency within the desired temperature range is within the reference range).

  Next, adjustment values 1 to N corresponding to the set value calculated in step S10 and the predicted set value error are written in the nonvolatile memory 60 (S20).

  Next, each data stored in the nonvolatile memory 60 is transferred to the register 70 (S30). For example, step S30 may be performed by restarting the oscillator 1 (oscillation IC 2) (turning on the power after turning off the power). By this step S30, the set value and the adjustment values 1 to N written in the nonvolatile memory 60 in step S20 are transferred to the register 70 and held.

  Next, the variable k is set to 1 (S40), and the selection value for selecting the adjustment value k is written to the register 70 (S50). By this step S50, the selection circuit 52 selects and outputs the adjustment value corresponding to the selection value among the adjustment values 1 to N held in the register 70, and the addition circuit 50 is held in the register 70. The set value and the selected adjustment value are added and output.

  Next, while varying the temperature of the oscillator 1 within a desired temperature range, the frequency of the oscillation signal output from the oscillator 1 (oscillation signal output from the external terminal OUT1) is measured to obtain the frequency-temperature characteristics of the oscillator 1 ( S60).

  If the frequency temperature characteristic of the oscillator 1 is within the reference range (Y in S70), the selection value for selecting the adjustment value k is written in the nonvolatile memory 60 (S80), and the process is terminated.

  On the other hand, if the frequency temperature characteristic of the oscillator 1 is not within the reference range (N in S70), if k <N (Y in S90), the variable k is increased by 1 (S100), and the processes after step S50 are performed. Do it again. If k ≧ N (N in S90), the process ends without performing step S80.

  In the flowchart of FIG. 5, when step S80 is completed, the frequency deviation satisfies the specification within a desired temperature range, and the oscillator 1 is determined to be an acceptable product for the inspection of the frequency temperature characteristics. Good. Moreover, when it complete | finishes without performing process S80, even if any adjustment value 1-N is selected, a frequency deviation shall not satisfy a specification within a desired temperature range, and the oscillator 1 is determined to be a rejected product. May be discarded.

  As described above, according to the first embodiment, the adjustment values 1 to N corresponding to the set value (temperature compensation data) obtained in the temperature compensation adjustment step and the predicted set value error are stored in the nonvolatile memory 60. Then, any one of the adjustment values 1 to N is selected, and temperature compensation is performed based on the added value of the set value and the selected adjustment value, whereby the frequency temperature characteristic of the oscillator 1 is Fine adjustments can be made to be within the reference range. Therefore, according to the oscillator 1 of the first embodiment, it is possible to achieve higher frequency accuracy than in the past.

  In addition, according to the present embodiment, when the oscillator 1 is started, an appropriate adjustment value is automatically selected based on the selection value stored in the non-volatile memory 60. Therefore, a signal for selecting the adjustment value Is not required to be input from the outside of the oscillator 1, and the user-friendly oscillator 1 can be realized.

  Furthermore, according to the present embodiment, the frequency of the oscillator 1 is measured in a state in which the temperature is compensated using the set value (temperature compensation data) obtained in the temperature compensation adjustment process, and even if the frequency is outside the reference range, it is long. Since it is not necessary to perform a time-consuming temperature compensation process again, the adjustment time can be greatly reduced as compared with the conventional frequency temperature characteristic adjustment method.

1-2. Second Embodiment The oscillator of the second embodiment is also a voltage-controlled temperature compensated oscillator similar to the oscillator of the first embodiment, and the same reference numerals are given to the same components as those of the first embodiment, and Then, the description which overlaps is abbreviate | omitted and it demonstrates focusing on difference with 1st Embodiment.

  FIG. 6 is a functional block diagram of the oscillator 1 according to the second embodiment. As shown in FIG. 6, the oscillator 1 of the second embodiment is the same as the oscillator 1 of the first embodiment except for the configuration of the nonvolatile memory 60 included in the oscillation IC 2.

  In the second embodiment, the non-volatile memory 60 has M banks 1 to M. Each of the banks 1 to M can store a set value, N adjustment values 1 to N, and a selection value, which are data for controlling the characteristics of the temperature compensation circuit 40, and the output circuit 20, frequency Data (not shown) for controlling the adjustment circuit 30 and the AFC circuit 32 also has a capacity capable of storing. Each data is written to any one of the banks 1 to M of the nonvolatile memory 60 from the external terminal of the oscillator 1 via the serial interface circuit 80. Then, the selection circuit 62 selects and outputs the setting value stored in the bank written last, and the selection circuits 64-1 to N have the adjustment value 1 stored in the bank written last. -N are selected and output, and the selection circuit 66 selects and outputs the selection value stored in the bank written last.

  Each data selected and output by the selection circuit 62, the selection circuits 64-1 to N, and the selection circuit 66 is registered when the oscillation IC 2 is turned on (when the voltage at the VDD terminal rises from 0V to a desired voltage). 70, and held in the register 70.

  Other configurations of the oscillator 1 of the second embodiment are the same as those of the first embodiment. In the oscillator 1 of the second embodiment configured as described above, for example, even if the nonvolatile memory 60 is a non-rewritable nonvolatile memory such as a one-time PROM, each data can be written while switching banks. As a result, each data can be written substantially M times (M-1 times of rewriting).

[Adjustment method of frequency temperature characteristics of oscillator]
FIG. 7 is a flowchart illustrating an example of a method for adjusting the frequency temperature characteristic of the oscillator 1 according to the second embodiment. Part of steps S200 to S320 in FIG. 7 may be omitted or changed, or other steps may be added. Moreover, you may change the order of each process suitably in the possible range. In the following, detailed description of the same steps as those in the flowchart of FIG. 5 is omitted. Prior to the flowchart of FIG. 7, it is assumed that data for controlling the output circuit 20, the frequency adjustment circuit 30, and the AFC circuit 32 are written in all of the banks 1 to M of the nonvolatile memory 60.

  In the example of FIG. 7, first, the variable j is set to 1 (S200), and the temperature of the oscillator 1 is varied within a desired temperature range to compensate the frequency temperature characteristic of the vibrator 3 in the same manner as in step S10 of FIG. A value is calculated (S210).

Next, the adjustment values 1 to N corresponding to the set value calculated in step S210 and the predicted set value error are written in the bank j of the nonvolatile memory 60 (S220). Through this step S220, the selection circuit 62 selects and outputs the setting value written in the bank j, and the selection circuits 64-1 to N select the adjustment values 1 to N written in the bank j, respectively. Output.

  Next, each data stored in the bank j of the nonvolatile memory 60 is transferred to the register 70 (S230). For example, step S230 may be performed by restarting the oscillator 1 (oscillation IC 2) (turning the power off and then turning on the power again). By this step S230, the setting values and adjustment values 1 to N written in the bank j of the nonvolatile memory 60 in step S220 (the setting values and adjustments selected and output by the selection circuit 62 and the selection circuits 64-1 to N, respectively). The values 1 to N) are transferred to the register 70 and held there.

  Next, the variable k is set to 1 (S240), and the selection value for selecting the adjustment value k is written in the register 70 (S250) as in step S50 of FIG.

  Next, as in step S60 of FIG. 5, the frequency of the oscillation signal output from the oscillator 1 (oscillation signal output from the external terminal OUT1) is measured while the temperature of the oscillator 1 is varied within a desired temperature range, and the oscillator 1 is acquired (S260).

  If the frequency temperature characteristic of the oscillator 1 is within the reference range (Y in S270), the selection value for selecting the adjustment value k is written in the bank j of the nonvolatile memory 60 (S280), and the process is terminated.

  On the other hand, if the frequency temperature characteristic of the oscillator 1 is not within the reference range (N in S270), if k <N (Y in S290), the variable k is increased by 1 (S300), and the processes after step S250 are performed. Do it again. Further, when k ≧ N (N in S290), when j <M (Y in S310), the variable j is incremented by 1 (S320), and the processes after step S210 are performed again, and j ≧ M At time (N in S310), the process ends without performing step S280.

  In the flowchart of FIG. 7, when step S280 is performed and the process is finished, the frequency deviation satisfies the specification within a desired temperature range. Good. Moreover, when it complete | finishes without performing process S280, even if any adjustment value 1-N is selected, a frequency deviation shall not satisfy a specification within a desired temperature range, and the oscillator 1 is determined to be a rejected product. May be discarded.

  The oscillator 1 of the second embodiment described above can achieve the same effects as the oscillator 1 of the first embodiment.

1-3. Modified Examples The oscillator 1 (oscillation IC 2) of each embodiment described above can be variously modified.

For example, in each of the embodiments described above, the selected value is written into the nonvolatile memory 60 in step S80 of the flowchart of FIG. 5 or step S280 of the flowchart of FIG. 7, but the nonvolatile memory 60 is not rewritable such as a one-time PROM. In the case of a possible non-volatile memory, the setting value and the adjustment values 1 to N are written in the non-volatile memory 60 in step S20 or step 220 prior to this, so that either the setting value or the adjustment values 1 to N Cannot assign selected value bits to the same address. Further, prior to the flowchart of FIG. 5 or the flowchart of FIG. 7, assuming that data for controlling the output circuit 20, the frequency adjustment circuit 30, and the AFC circuit 32 are written in the nonvolatile memory 60. The bit of the selection value cannot be assigned to the same address as each data. In this case, it is necessary to provide a dedicated address for the selected value, so that there is a possibility that the bit of the address is vacant and the nonvolatile memory 60 increases unnecessarily.

  When the non-volatile memory 60 is a rewritable non-volatile memory such as an EEPROM, for example, a bit of the selected value can be assigned to the same address as the set value. However, the set value differs for each oscillator 1 and is a fixed value. Therefore, it is necessary to once read the setting value from the nonvolatile memory 60 and overwrite the nonvolatile memory 60 with the same setting value together with the selected value, which is a little troublesome. Further, the adjustment values 1 to N are set as fixed values to the same address as any of these, or the same address as the fixed value data among the data for controlling the output circuit 20, the frequency adjustment circuit 30 and the AFC circuit 32, respectively. The bits of the selected value can also be assigned, but if the bits of the address are vacant, the nonvolatile memory 60 may increase unnecessarily.

  Therefore, for example, the above-described embodiments may be modified such that the selection value is not stored in the nonvolatile memory 60 and the selection value is set by the fuse circuit. FIG. 8 is a functional block diagram of a modified oscillator 1 in which the oscillator 1 according to the first embodiment is modified so that a selection value is set by a fuse circuit. As shown in FIG. 8, the oscillator 1 of this modification example does not store the selection value in the nonvolatile memory 60, and the selection circuit 54 and the fuse circuit 90 are added to the oscillation IC 2. Is different.

  The fuse circuit 90 outputs a selection value for selecting any one of the adjustment values 1 to N. By cutting a part of the internal wiring (not shown) of the fuse circuit 90, a selection value for selecting any one of the adjustment values 1 to N can be arbitrarily set.

  The selection circuit 54 selects and outputs either the selection value held in the register 70 or the selection value output from the fuse circuit 90. In this modification, the selection circuit 54 selects and outputs the selection value held in the register 70 before the desired selection value is set in the fuse circuit 90 (when the flowchart of FIG. 5 is executed). After a desired selection value is set in the fuse circuit 90, the output value of the fuse circuit 90 is selected and output. Such control of the selection circuit 54 can be realized, for example, by switching the mode from the outside via the serial interface circuit 80, or the fuse circuit 90 can control the selection circuit 54 according to the set selection value. It can also be realized by configuring to output a control signal.

  The selection circuit 52 selects any one of the adjustment values 1 to N based on the selection value output from the selection circuit 54. Accordingly, after a desired selection value is set in the fuse circuit 90, the selection circuit 52 selects one of the adjustment values 1 to N based on the selection value output from the fuse circuit 90.

  Although not shown, the flowchart showing an example of the method for adjusting the frequency temperature characteristic of the oscillator 1 of this modification is the same as the flowchart of FIG. 5 except for step S80. In step S80, the selected value is set to a non-volatile value. Instead of writing in the memory 60, a part of the wiring of the fuse circuit 90 may be cut to set the selection value.

  According to the present modification, for example, when the oscillator 1 is started, an appropriate adjustment value is automatically selected based on the selection value output from the fuse circuit 90. Therefore, a signal for selecting the adjustment value is sent to the oscillator 1 Therefore, it is possible to realize an easy-to-use oscillator 1. Also, according to this modification, unlike the first embodiment or the second embodiment, there is no need to read the set value and write the set value and the selected value at the same time. There is no problem that the area is unnecessarily increased.

2. Electronic Device FIG. 9 is a functional block diagram showing an example of the configuration of the electronic device of the present embodiment. Moreover, FIG. 10 is a figure which shows an example of the external appearance of the smart phone which is an example of the electronic device of this 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. 9 are omitted or changed, or other components are added.

  The oscillator 310 includes an oscillation circuit 312 and a vibrator 313. The oscillation circuit 312 oscillates the vibrator 313 and generates an oscillation signal. This oscillation signal is output from the OUT terminal of the oscillator 310 to the CPU 320.

  The CPU 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 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 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 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 oscillation IC 2 of the above-described embodiment as the oscillation circuit 312 or applying the oscillator 1 of the above-described embodiment as the oscillator 310, a highly reliable electronic device 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, the communication unit 360 receives an external clock signal, and the CPU 320 (processing unit) generates an oscillator based on the external clock signal and an output signal (internal clock signal) of the oscillator 310. A communication device including a frequency control unit that controls the frequency of 310. This communication device may be, for example, a backbone network device such as stratum 3 or a communication device used for a femtocell.

  The network device has an accurate time because it runs through a time synchronization network. The network device located at the end of the time synchronization network is more likely to lose synchronization or time fluctuation (time shift). Since the oscillator 310 of the present embodiment can realize a frequency temperature characteristic with extremely high accuracy of 0.1 ppm or less, this time fluctuation is corrected, and it is suitable as an alternative clock source when the synchronization is lost. For example, by providing the oscillator 310 corresponding to the Stratum 3 standard, the conditions such as jitter, wander, holdover, etc., defined in the SyncE (Synchronous Ethernet (registered trademark)) standard that defines the communication method of the synchronous Ethernet, etc. A network device that can be satisfied can be realized.

  A femtocell is an extremely small base station that is assumed to be installed in an office or home among mobile phone base stations (cells). The radio wave output range covered by the femtocell is a radius. It is about several tens of meters. The femtocell connects to the mobile phone network through a broadband line. Even in places such as office spaces surrounded by buildings, where sufficient radio wave conditions could not be secured with conventional mechanisms, calls can be secured by installing femtocells. Femtocell is also attracting attention from the viewpoint that it will be possible to introduce FMC (Fixed Mobile Convergence), a service that uses a fixed communication line to fuse dismantled telephones with fixed telephones.

3. FIG. 11 is a diagram (top view) illustrating an example of a moving object according to the present embodiment. A moving body 400 shown in FIG. 11 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. 11 are omitted or other components are added.

  The oscillator 410 includes an oscillation circuit (not shown) and a vibrator, and the oscillation circuit oscillates the vibrator and generates an oscillation signal. This oscillation signal is output from the external terminal of the oscillator 410 to the controllers 420, 430, and 440, and is 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, for example, the oscillation IC 2 of the above-described embodiment as the oscillation circuit included in the oscillator 410, or by applying, for example, the oscillator 1 of the above-described embodiment as the oscillator 410, a highly reliable moving body can be realized. it can.

  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.

  For example, the oscillator according to the embodiment and the modification described above is an oscillator (VC-TCXO (Voltage Controlled Temperature Compensated Crystal Oscillator) or the like) having a temperature compensation function and a voltage control function (frequency control function). Voltage-controlled oscillators (VCXO (Voltage Controlled Crystal Oscillator) etc.) without temperature compensation function, temperature-compensated oscillators (TCXO (Temperature Compensated Crystal Oscillator) etc.) without voltage control function (frequency control function), temperature Also applicable to oscillators such as oscillators (SPXO (Simple Packaged Crystal Oscillator), etc.) and temperature chamber oscillators (OCXO (Oven Controlled Crystal Oscillator), etc.) that do not have both compensation function and voltage control function (frequency control function) be able to.

  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 Oscillator IC, 3 Oscillator, 4 Package, 5 Lid, 6 External terminal (external electrode), 7a, 7b Storage chamber, 8 Sealing member, 10 Oscillator circuit, 20 Output circuit, 30
Frequency adjustment circuit, 32 AFC circuit, 40 temperature compensation circuit, 42 temperature sensor, 50
Adder circuit, 52 selection circuit, 54 selection circuit, 60 nonvolatile memory, 62 selection circuit, 64-1 to 64-N selection circuit, 66 selection circuit, 70 register, 80 serial interface (I / F) circuit, 90 fuse circuit , 300 electronic equipment, 310 oscillator, 312 oscillator circuit, 313 oscillator, 320 CPU, 330 operation unit, 340
ROM, 350 RAM, 360 communication unit, 370 display unit, 400 moving body, 410
Oscillator, 420, 430, 440 Controller, 450 battery, 460 Backup battery

Claims (6)

A temperature compensation circuit;
An oscillation circuit to which an output signal of the temperature compensation circuit is input;
Non-volatile memory,
And an adder circuit,
The nonvolatile memory stores a set value of the temperature compensation circuit and at least one adjustment value,
The adder circuit
An oscillator that adds the set value and any of the adjustment values and outputs the sum to the temperature compensation circuit. Including a selection circuit,
The nonvolatile memory stores a plurality of the adjustment values,
The selection circuit selects one of the plurality of adjustment values;
The adder circuit
The oscillator according to claim 1, wherein the set value and the adjustment value selected by the selection circuit are added and output to the temperature compensation circuit. The non-volatile memory stores a selected value,
The selection circuit includes:
The oscillator according to claim 2, wherein the adjustment value is selected based on the selection value. Including a fuse circuit that outputs the selected value,
The selection circuit includes:
The oscillator according to claim 2, wherein the adjustment value is selected based on the selection value.   An electronic device comprising the oscillator according to claim 1.   A moving body comprising the oscillator according to claim 1.

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