JP2006303764A - Temperature compensation method of temperature compensation oscillation circuit, temperature compensation oscillation circuit, piezoelectric device, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature compensation method of a temperature compensation oscillation circuit, the temperature compensation oscillation circuit, a piezoelectric device, and an electronic apparatus with less power consumption. <P>SOLUTION: The temperature compensation oscillation circuit provides an output of correction value data in response to ambient temperature of a piezoelectric vibrator to apply temperature compensation to the frequency temperature characteristic of the piezoelectric vibrator on the basis of the correction value data, and is configured to include: a circuit for receiving the correction value data and providing an output as it is; a circuit for receiving the first correction value data and second correction value data, obtaining a median data for interpolating between these correction value data and providing an output of the median data; and a means that receives and latches the correction value data or the median data, and delays the latched data in matching with a temperature time constant of the piezoelectric vibrator and provides an output. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a temperature compensation method for a temperature compensated oscillation circuit, a temperature compensated oscillation circuit, a piezoelectric device, and an electronic device, and more particularly to a digital temperature compensation type oscillation circuit.

  As shown in FIG. 9, the temperature compensated oscillation circuit 1 according to the prior art includes an oscillation circuit 3 to which a piezoelectric vibrator 2 is connected. The oscillation circuit 3 is provided with a capacitor array for adjusting the oscillation frequency of the piezoelectric vibrator 2, and the oscillation frequency is changed by changing the capacitance value of the capacitor array. The temperature compensated oscillation circuit 1 includes a temperature sensor 4 that measures the ambient temperature of the piezoelectric vibrator 2. The temperature sensor 4 outputs the measurement result as an analog signal to an analog / digital (A / D) converter 5, and the A / D converter 5 converts the analog signal into a digital signal and outputs the digital signal to the storage unit 6. Is.

  The storage unit 6 stores correction value data. This correction value data is data for setting the capacitance array to a capacitance value corresponding to the temperature measured by the temperature sensor 4 in order to set the oscillation signal output from the temperature compensated oscillation circuit 1 to a constant frequency. Therefore, the temperature of the piezoelectric vibrator 2 measured by the temperature sensor 4 and the correction value data are associated with each other on a one-to-one basis.

  When the digital signal output from the A / D converter 5 is input to the storage unit 6, the correction value data corresponding to the temperature is read and output to the oscillation circuit 3. When the correction circuit receives the correction value data, the oscillation circuit 3 sets the capacitance array so as to have a capacitance value based on the correction value data, and adjusts the oscillation frequency of the piezoelectric vibrator 2 to adjust the oscillation frequency to a constant frequency. Output a signal. In this way, the temperature compensated oscillation circuit 1 performs temperature compensation on the frequency temperature characteristic of the piezoelectric vibrator 2.

Patent Document 1 is an example of a document that discloses a temperature compensated piezoelectric oscillation circuit. The oscillation circuit (oscillator) disclosed in Patent Document 1 performs data generation by intermediate value interpolation for correction table compression.
JP-A-8-130411

  In the temperature compensated oscillation circuit described above, power is consumed each time the temperature sensor is operated to output a digital signal to the storage unit and read correction value data from the storage unit. In addition, when the temperature-compensated oscillation circuit is mounted on an electronic device, there are times when it is desired to operate the temperature-compensated oscillation circuit even when the electronic device is in the sleep mode (power saving mode). Electric power is consumed, and when the electronic device is operated by a battery, the battery is quickly consumed.

  When a piezoelectric vibrator is connected to the oscillation circuit of the temperature compensated oscillation circuit and configured as a real time clock, the temperature compensated oscillation circuit is often used as a sleep clock during backup. However, when the temperature sensor, A / D converter, and storage unit of the temperature compensated oscillation circuit operate, the current consumption during steady oscillation is lower than that of a low frequency (eg, 32.768 kHz) oscillation circuit without a temperature compensation function. Since it is 300 to 400 times and consumes a lot of power, it is not preferable to operate the temperature sensor or the like frequently during backup.

  For this reason, there is a case where a temperature sensor, an A / D converter, and a storage unit are intermittently operated to suppress an average current consumption. However, if the intermittent operation intervals of the temperature sensor, the A / D converter, and the storage unit are increased, the followability with respect to the temperature change is lowered, and the temperature correction amount is increased once. As the temperature correction amount increases, the output frequency of the temperature compensated oscillation circuit may change greatly before and after the temperature correction.

In addition, since the piezoelectric vibrator has a configuration in which a piezoelectric vibrating piece is sealed inside a package or the like, it takes time for the temperature of the piezoelectric vibrating piece to reach the ambient temperature even if the ambient temperature of the piezoelectric oscillator changes. . Similarly, the temperature sensor is a circuit element formed in an IC chip housed in a package or the like, or an external component connected to the IC chip, so that the ambient temperature of the piezoelectric oscillator changes. However, it takes time for the temperature of the temperature sensor to reach its ambient temperature. Therefore, there is a problem that accurate temperature compensation cannot be performed in the piezoelectric oscillator in which the time constant (temperature time constant) with respect to the ambient temperature change is different between the temperature of the temperature sensor and the temperature of the piezoelectric vibrator. It was.
An object of the present invention is to provide a temperature compensation method for a temperature compensated oscillation circuit, a temperature compensated oscillation circuit, a piezoelectric device, and an electronic apparatus with low power consumption.

  In order to achieve the above object, the temperature compensation method of the temperature compensated oscillation circuit according to the present invention intermittently measures the ambient temperature of the piezoelectric vibrator by the temperature measurement unit, and from the correction value data stored in advance, Obtaining the correction value data corresponding to the measured temperature, adjusting the means for temperature compensation of the frequency temperature characteristics of the piezoelectric vibrator by delaying a predetermined time from the temperature measurement based on the correction value data, From the obtained correction value data of the last two times, intermediate value data to be interpolated between them is obtained, and the means for temperature compensating the frequency temperature characteristics of the piezoelectric vibrator is adjusted based on the intermediate value data. It is characterized by that. When the temperature compensated oscillation circuit is operated by such a method, the followability of the temperature compensation with respect to the change of the ambient temperature is improved, so that the amount of temperature change by one temperature compensation can be reduced. Therefore, highly accurate temperature compensation can be performed, and power consumption can be reduced.

  Further, the means for temperature compensation is adjusted based only on the correction value data. Since intermediate value data is not obtained, power required for obtaining intermediate value data can be reduced. Therefore, the temperature compensated oscillation circuit can be further reduced in power consumption.

  The temperature compensated oscillation circuit according to the present invention outputs correction value data according to the ambient temperature of the piezoelectric vibrator, and temperature compensated oscillation circuit for temperature compensating the frequency temperature characteristic of the piezoelectric vibrator based on the correction value data. The correction value data is inputted and outputted as it is, and the first correction value data and the second correction value data are inputted, and the correction value data is interpolated. A circuit for obtaining and outputting intermediate value data, and means for inputting and holding the correction value data or the intermediate value data, and delaying and outputting the data held in accordance with the temperature time constant of the piezoelectric vibrator It is characterized by having. The intermediate value data is output between the first correction value data and the second correction value data.

  As a result, correction value data can be obtained based on the temperature when the ambient temperature of the piezoelectric vibrator is measured, and the temperature can be compensated. Also, during the measurement of the ambient temperature of the piezoelectric vibrator, interpolation is performed between the two. Interpolated temperature compensation can be performed by obtaining intermediate value data. The piezoelectric vibrator takes time to reach the temperature when the temperature sensor measures the temperature. For this reason, correction value data or intermediate value data is output in accordance with the temperature time constant of the piezoelectric vibrator, so temperature compensation is performed when the piezoelectric vibrator reaches the temperature when the temperature sensor measures the temperature. Can do. Therefore, accurate temperature compensation can be performed.

  One or more intermediate value data are output. If intermediate value data is output between correction value data, the number of times temperature compensation is performed increases, so that temperature compensation can be improved with respect to changes in ambient temperature, and temperature is changed by one temperature compensation. The amount can be reduced.

  A temperature measurement unit that outputs measurement data obtained by measuring the ambient temperature of the piezoelectric vibrator as a digital signal; and a storage unit that inputs the measurement data and outputs correction value data stored in advance corresponding to the measurement data; A correction value determination circuit that inputs the correction value data and outputs the correction value data or intermediate value data; and outputs an oscillation signal that is temperature-compensated according to the input correction value data or intermediate value data. An oscillation circuit connected to the piezoelectric vibrator, wherein the correction value determination circuit inputs and holds the correction value data from the storage unit, and the first storage unit Connected to the subsequent stage, connected to the second storage unit for inputting and temporarily holding the correction value data output from the first storage unit, and the subsequent stage of the first storage unit and the second storage unit, First Intermediate value calculation means for obtaining intermediate value data by inputting the correction value data output from the storage section and the correction value data output from the second storage section, the first storage section and the intermediate value calculation means Connected to the subsequent stage, inputs the correction value data and the intermediate value data, and outputs one of the selection means, connected to the subsequent stage of the selection means, holds the data output from the selection means, And a third storage unit that delays and outputs the data held in accordance with the temperature time constant of the piezoelectric vibrator.

  The temperature measuring unit measures the temperature intermittently. The temperature compensated oscillation circuit can compensate the temperature by obtaining correction value data based on the temperature measured by the temperature measurement unit. Further, the temperature compensated oscillation circuit can compensate for the temperature by obtaining the intermediate value data by the intermediate value calculation means while the temperature measurement unit is not measuring the temperature. That is, the temperature-compensated oscillation circuit can compensate the interpolation temperature with the intermediate value data during the temperature compensation based on the correction value data. Therefore, it is possible to improve the follow-up performance of temperature compensation with respect to changes in ambient temperature, and the amount of change in temperature can be reduced by a single temperature compensation, so that power consumption can be reduced. Furthermore, if correction value data or intermediate value data is output in accordance with the temperature time constant of the piezoelectric vibrator, temperature compensation can be performed when the piezoelectric vibrator reaches the temperature when the temperature is measured by the temperature measuring unit. . Therefore, accurate temperature compensation can be performed.

  Further, the above-described temperature compensated oscillation circuit is characterized in that a timing circuit having at least a clock function is connected. This makes it possible to configure a real time clock. Even when a real-time clock is used, the temperature compensated oscillation circuit having the above-described characteristics is provided, so that temperature compensation can be performed intermittently and power consumption can be reduced.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a temperature compensation method for a temperature compensated oscillation circuit, a temperature compensated oscillation circuit, a piezoelectric device, and an electronic device according to the present invention will be described below. First, the first embodiment will be described. FIG. 1 is a schematic explanatory diagram of a correction value determination circuit. FIG. 2 is a block diagram illustrating a temperature compensated oscillation circuit. The temperature compensated oscillation circuit 10 includes an oscillation circuit 22 to which a temperature measurement unit 12, a storage unit 18, a correction value determination circuit 30, and a piezoelectric vibrator 20 are connected.

  The correction value determination circuit 30 shown in FIG. 2 inputs a correction value data from the storage unit 18 and outputs the correction value data as it is (first correction value data input from the storage unit 18). And intermediate value data output circuit (not shown) which is a circuit for calculating intermediate value data using the second correction value data newly input from the storage unit 18 and outputting the intermediate value data. Yes. The correction value determination circuit 30 receives and holds the correction value data output from the correction value data output circuit or the intermediate value data output from the intermediate value data output circuit, and the temperature of the piezoelectric vibrator 20. Means for delaying and outputting data held in accordance with a time constant.

  Specifically, the correction value determination circuit 30 shown in FIG. 1 includes a first storage unit 32, a second storage unit 34, an intermediate value calculation unit 36, a selection unit 38, a third storage unit 40, and a control unit 42. ing. The first storage unit 32 receives the correction value data from the storage unit 18 and holds it until the next correction value data is input. The second storage unit 34 is connected to the subsequent stage of the first storage unit 32, receives the correction value data output from the first storage unit 32, and temporarily holds it until the next correction value data is input. is there. The intermediate value calculation means 36 is connected to the subsequent stage of the first storage unit 32 and the second storage unit 34, and the correction value data output from the first storage unit 32 and the next correction value output from the second storage unit 34. The intermediate value data is obtained by inputting the data. The selection unit 38 is connected to the subsequent stage of the first storage unit 32 and the intermediate value calculation unit 36, and receives the correction value data from the first storage unit 32 and the intermediate value data from the intermediate value calculation unit 36. One of them is output. The first storage unit 32 and the selection means 38 constitute the correction value data output circuit. The second storage unit 34, the intermediate value calculation means 36, and the selection means 38 constitute the intermediate value data output circuit. The third storage unit 40 is connected to the subsequent stage of the selection unit 38, holds correction value data or intermediate value data output from the selection unit 38, and holds data according to the temperature time constant of the piezoelectric vibrator 20. Is output with a delay.

  The correction value determining circuit 30 includes a control unit 42, and the control unit 42 includes a delay unit 44. The control unit 42 outputs a selection signal to the selection unit 38 based on a control signal input from the outside, and outputs a delay signal to the third storage unit 40. Specifically, the control means 42 outputs a selection signal to the selection means 38 and causes the selection means 38 to select either correction value data or intermediate value data. In addition, the control unit 42 outputs a delay signal indicating a delay time in accordance with the temperature time constant of the piezoelectric vibrator 20 set in the delay unit 44 to the third storage unit 40 and holds the delay signal in the third storage unit 40. The correction value data or the intermediate value data is output with a delay in accordance with the temperature time constant of the piezoelectric vibrator 20.

  The piezoelectric vibrator 20 shown in FIG. 2 oscillates at a predetermined frequency, and may be a tuning fork type piezoelectric vibrator, a piezoelectric vibrator such as an AT cut, a surface acoustic wave resonator, or the like. The piezoelectric vibrator 20 is a piezoelectric vibrating piece in which an electrode is provided on a piezoelectric substrate and hermetically sealed in the package. For this reason, the piezoelectric vibrating reed is housed in a package and hermetically sealed. Therefore, even if the ambient temperature of the piezoelectric vibrator 20 changes, the temperature does not immediately follow the temperature change, and a certain amount of time passes. Temperature changes. That is, the piezoelectric vibrator 20 has a temperature time constant.

  Further, the oscillation circuit 22 shown in FIG. 2 oscillates the piezoelectric vibrator 20. The oscillation circuit 22 includes a frequency adjustment element such as a capacitance array or a variable capacitance diode. The frequency adjusting element adjusts the oscillation frequency of the piezoelectric vibrator 20 by changing an element value (capacitance value) according to correction value data or intermediate value data. That is, the frequency adjusting element is a means for temperature compensating the frequency temperature characteristic of the piezoelectric vibrator. In the capacitance array, a plurality of capacitors are connected in parallel, and a switch connected to each capacitor is ON / OFF controlled according to correction value data or intermediate value data to change the capacitance value.

  The temperature measuring unit 12 shown in FIG. 2 includes a temperature sensor 14 and an analog / digital (A / D) converter 16. The temperature sensor 14 measures the ambient temperature of the piezoelectric vibrator 20 and outputs the measurement result as an analog signal. The A / D converter 16 converts the analog signal input from the temperature sensor 14 into a digital signal and outputs it to the storage unit 18. Correction value data is stored in the storage unit 18 in advance, and correction value data corresponding to a digital signal input from the correction value data is output. The correction value data has a one-to-one correspondence with the temperature. When the element value of the frequency adjusting element is adjusted based on this data, the frequency of the oscillation signal is adjusted, and the frequency temperature characteristic of the piezoelectric vibrator 20 is temperature compensated. Is done.

  Next, the operation of the temperature compensated oscillation circuit 10 will be described. FIG. 3 is a diagram for explaining the timing of temperature compensation. First, the temperature compensated oscillation circuit 10 measures the ambient temperature of the piezoelectric vibrator 20 with the temperature sensor 14 (black circle A shown in FIG. 3). The measurement result is output to the A / D converter 16 as an analog signal. The A / D converter 16 converts the analog signal into a digital signal and outputs it to the storage unit 18. That is, the temperature measurement unit 12 outputs measurement data obtained by measuring the ambient temperature of the piezoelectric vibrator 20 as a digital signal. When the digital signal is input, the storage unit 18 reads out correction value data corresponding to the input digital signal from the correction value data stored in advance, and outputs the correction value data to the correction value determination circuit 30.

  The correction value data is input to the first storage unit 32 of the correction value determination circuit 30, temporarily stored in the first storage unit 32, and output to the selection unit 38 and the second storage unit 34. The second storage unit 34 temporarily stores and holds the correction value data input from the first storage unit 32. The selection unit 38 is set to select the correction value data based on the selection signal output from the control unit 42. The correction value data selected by the selection unit 38 is output to the third storage unit 40.

  The third storage unit 40 temporarily stores and holds the input correction value data. And the 3rd memory | storage part 40 delays and outputs correction value data according to the delay signal output from the control means 42 (delay means 44). The time for delaying and outputting the correction value data (delay time) is arbitrarily set according to the temperature time constant of the piezoelectric vibrator 20. That is, the delay time matches or substantially matches the time until the piezoelectric vibrator 20 reaches the temperature when the temperature is measured by the temperature sensor 14.

  The correction value data output from the third storage unit 40, that is, the correction value determination circuit 30, is input to the frequency adjustment element of the oscillation circuit 22, and the frequency adjustment element is set to an element value corresponding to the correction value data. The As a result, the oscillation frequency of the piezoelectric vibrator 20 is adjusted, and an oscillation signal having a constant frequency is output from the oscillation circuit 22. Therefore, the temperature-temperature characteristic of the piezoelectric vibrator 20 is compensated for temperature (black circle Xn-1 shown in FIG. 3).

  Next, the temperature measurement unit 12 newly measures the ambient temperature of the piezoelectric vibrator 20 (black circle B shown in FIG. 3), converts the measurement data into a digital signal, and outputs the digital signal. The A / D converter 16 converts the analog signal into a digital signal and outputs it to the storage unit 18. When new correction value data is input, the first storage unit 32 stores and holds the new correction value data and outputs it to the selection means 38 and the intermediate value calculation means 36. Further, the second storage unit 34 outputs the correction value data (correction value data obtained by the measurement at the time of the black circle A shown in FIG. 3) stored and held to the intermediate value calculation means 36.

  The intermediate value calculation unit 36 obtains intermediate value data from the correction value data input from the second storage unit 34 and the new correction value data input from the first storage unit 32. The intermediate value data is the element of the frequency adjusting element corresponding to the temperature between the previous temperature measurement (in the case of the black circle A shown in FIG. 3) and the new temperature measurement (in the case of the black circle B shown in FIG. 3). Data for adjusting the value. As a specific example, the intermediate value data is correction value data at a temperature obtained by averaging the temperature at the previous temperature measurement and the temperature at the new temperature measurement. The selection unit 38 selects the intermediate value data based on the selection signal input from the control signal, and the intermediate value data is output to the third storage unit 40. The third storage unit 40 delays and outputs the intermediate value data according to the delay signal output from the control means 42 (delay means 44).

  Then, the correction value data output from the third storage unit 40, that is, the correction value determination circuit 30, is input to the frequency adjustment element of the oscillation circuit 22, and the frequency adjustment element is set to an element value corresponding to the intermediate value data. Is done. As a result, the oscillation frequency of the piezoelectric vibrator 20 is adjusted, and an oscillation signal having a constant frequency is output from the oscillation circuit 22. Therefore, the temperature-temperature characteristic of the piezoelectric vibrator 20 is compensated for temperature (white circle Yn shown in FIG. 3).

  Next, after a lapse of a certain time (when the piezoelectric vibrator 20 reaches the temperature measured at the time of the black circle B), the control unit 42 outputs new correction value data output from the first storage unit 32 by the selection unit 38. A selection signal is output to the selection means 38 so as to make a selection. The new correction value data is temporarily stored and held in the third storage unit 40, and is delayed from the third storage unit 40 according to the delay signal output from the control unit 42 (delay unit 44). The The frequency adjusting element is set to an element value corresponding to new correction value data. As a result, the oscillation frequency of the piezoelectric vibrator 20 is adjusted, and an oscillation signal having a constant frequency is output from the oscillation circuit 22. Therefore, the temperature-temperature characteristic of the piezoelectric vibrator 20 is compensated for temperature (black circle Xn shown in FIG. 3). The temperature compensated oscillation circuit 10 repeats the above operation to perform temperature compensation.

  Such a temperature-compensated oscillation circuit 10 performs temperature compensation based on the temperature when the ambient temperature of the piezoelectric vibrator 20 is intermittently measured by the temperature sensor 14 and is also an intermediate value during the temperature measurement. Temperature compensation is performed for data. That is, the temperature compensated oscillation circuit 10 performs temperature compensation by performing interpolation. When the intermediate value data is obtained by taking the average of the first correction value data and the second correction value data, the relationship between the temperature compensation Xn−1, Xn and Yn is Yn = (Xn + Xn−1) / 2 For this reason, since the follow-up performance of the temperature compensation with respect to the temperature change is improved, the adjustment amount of one temperature compensation does not become large, high-precision temperature compensation can be performed, and low power consumption can be achieved. Further, if the temperature compensation interval using the correction value data and the intermediate value data is the same, the amount of adjustment can be reduced, so that the change in the output frequency can be further suppressed.

Further, by providing the delay means 44, the correction value data or the intermediate value data can be output when the piezoelectric vibrator 20 (piezoelectric vibrating piece) reaches the temperature when the temperature sensor 14 measures the temperature. Even if there is a difference in temperature time constant between the piezoelectric vibrator 20 and the piezoelectric vibrator 20, accurate temperature compensation can be performed.
Further, since the correction value determination circuit 30 does not require a complicated arithmetic circuit, it is possible to suppress an increase in circuit, an increase in cost, and an increase in current consumption due to the addition of functions.

As a modification of the present embodiment, the intermediate value calculation means 36, as shown in FIG. 4, is used when measuring the previous temperature (black circle A shown in FIG. 4) and when measuring a new temperature (black circle B shown in FIG. 4). And the intermediate value data may be obtained and output. Thereby, more accurate temperature compensation can be performed. Further, the intermediate value calculation means 36 may obtain and output intermediate value data when the time between the previous temperature measurement and the new temperature measurement is divided into four or more.
The temperature compensated oscillation circuit 10 described in the first embodiment constitutes a temperature compensated piezoelectric oscillator that is a piezoelectric device.

  Next, a second embodiment will be described. The temperature compensated oscillation circuit according to the second embodiment has the same configuration as that of the temperature compensated oscillation circuit described in the first embodiment, and part of the operation is different. Therefore, in the second embodiment, the description of the same configuration as the first embodiment is omitted. FIG. 5 is a schematic explanatory diagram of a correction value determination circuit according to the second embodiment. The temperature-compensated oscillation circuit according to the second embodiment is configured such that an interpolation operation is not performed only when an interpolation invalid signal is detected by inputting an external interpolation invalid signal to the correction value determining circuit 30. It is. That is, the correction value determination circuit 30 of the second embodiment is configured to output only correction value data and not output intermediate value data when an interpolation invalid signal is input, and does not perform interpolation compensation.

  The temperature compensated oscillation circuit operates in the same manner as described in the first embodiment when no interpolation invalid signal is input. That is, when no interpolation invalid signal is input, the correction value determination circuit 30 outputs correction value data and intermediate value data, and the temperature compensation oscillation circuit performs interpolation compensation.

  The temperature compensated oscillation circuit according to the second embodiment operates as follows when an interpolation invalid signal is input from the outside. That is, the temperature compensated oscillation circuit inputs the interpolation invalid signal to the control means 42. When the interpolation invalid signal is input, the control unit 42 outputs the interpolation invalid signal to the second storage unit 34 and the intermediate value calculation unit 36 so that the second storage unit 34 and the intermediate value calculation unit 36 are not operated. . Further, the control unit 42 outputs a selection signal to the selection unit 38 and sets the selection unit 38 to select only the correction value data output from the first storage unit 32. At this time, since the correction value determination circuit 30 does not operate the second storage unit 34, the intermediate value calculation unit 36, and the selection unit 38, it is possible to reduce power consumption. As a result, the temperature compensated oscillation circuit outputs only correction value data.

By configuring such a temperature compensated oscillation circuit, power consumption can be further reduced. When the temperature-compensated oscillation circuit is mounted on the electronic device, the electronic device main body outputs an interpolation invalid signal to the temperature-compensated oscillation circuit when the electronic device shifts to the sleep mode (power saving mode). If so, the temperature-compensated oscillation circuit stops the operations of the second storage unit 34, the intermediate value calculation unit 36, and the selection unit 38 that are normally operated, and thus the power consumption of the electronic device can be further reduced.
The temperature compensated oscillation circuit described in the second embodiment constitutes a temperature compensated piezoelectric oscillator that is a piezoelectric device.

  Next, a third embodiment will be described. In the third embodiment, a piezoelectric device that is the temperature compensated oscillator described in the first and second embodiments will be described. In the piezoelectric device according to the third embodiment, a real time clock is configured by connecting a clock circuit to the subsequent stage of the temperature compensated oscillation circuit described in the first and second embodiments. Therefore, the description of the same configuration as the first and second temperature compensated oscillation circuits is omitted.

  FIG. 6 is an explanatory diagram of the piezoelectric device according to the third embodiment. The clock circuit 52 connected to the subsequent stage of the temperature compensation oscillation circuit, that is, the subsequent stage of the oscillation circuit 22 includes a frequency divider 54 and a clock / calendar circuit 56. The frequency divider 54 divides the oscillation signal output from the oscillation circuit 22 by a predetermined frequency division ratio. The clock / calendar circuit 56 displays or outputs a clock or calendar based on an output signal from the frequency divider 54.

  As a result, the piezoelectric device 50 can adjust the oscillation frequency of the source oscillation and display or output a clock or calendar based on the oscillation signal that has been subjected to temperature compensation with high accuracy. Further, since the piezoelectric device 50 performs temperature compensation intermittently, it is possible to reduce power consumption.

  Next, a fourth embodiment will be described. In the fourth embodiment, a real-time clock that is a piezoelectric device will be described. In the fourth embodiment, if it is a part having the same configuration as the part described in the first and second embodiments, the description is omitted or simplified. FIG. 7 is an explanatory diagram of a piezoelectric device according to the fourth embodiment. A piezoelectric device 60 according to the fourth embodiment includes a temperature sensor 14, an A / D converter 16, a storage unit 18, a correction value determination circuit 30, an oscillation circuit 22 connected with the piezoelectric vibrator 20, and a clock circuit 62. Yes. The clock circuit 62 includes a logic slow / fast circuit 64 and a clock / calendar circuit 66. In addition, each part of the temperature sensor 14, the A / D converter 16, the storage unit 18, the correction value determination circuit 30, the piezoelectric vibrator 20, and the oscillation circuit 22 is the same as each part described in the first and second embodiments. It is a configuration.

  In the piezoelectric device 60, the temperature sensor 14, the A / D converter 16, the storage unit 18, and the correction value determination circuit 30 are connected in series as in the first and second embodiments. The subsequent stage of the correction value determining circuit 30 is connected to a logic slow / fast circuit 64 in the clock circuit 62. The subsequent stage of the oscillation circuit 22 to which the piezoelectric vibrator 20 is connected is also connected to a logic slow / fast circuit 64 in the clock circuit 62. The logic slow / fast circuit 64 includes a frequency divider, changes the frequency division ratio based on the correction value data or intermediate value data output from the correction value determination circuit 30, and outputs the oscillation signal output from the oscillation circuit 22. By dividing the frequency, the frequency temperature characteristic of the piezoelectric vibrator 20 is compensated for temperature. The logic slow / fast circuit 64 serves as a means for temperature compensation of the frequency temperature characteristics of the piezoelectric vibrator 20. The clock / calendar circuit 66 displays or outputs a clock or calendar based on the output signal from the logic slow / fast circuit 64.

  When the piezoelectric device 60 is configured in this way, the piezoelectric device 60 divides the oscillation signal based on the correction value data and the intermediate value data output from the correction value determination circuit 30, and thus the frequency temperature of the piezoelectric vibrator 20. The characteristic is temperature-compensated with high accuracy, and a clock or calendar can be displayed and output based on the oscillation signal that has been subjected to temperature compensation with high accuracy. Moreover, since the piezoelectric device 60 performs temperature compensation intermittently, it is possible to reduce power consumption.

  Next, a fifth embodiment will be described. In the fifth embodiment, an electronic apparatus in which the temperature compensated oscillation circuit 10 and the piezoelectric devices 50 and 60 are mounted will be described. The temperature compensated oscillation circuit (temperature compensated piezoelectric oscillator) described in the first and second embodiments can be mounted on an electronic device that requires an oscillation signal having a constant frequency. The piezoelectric devices (real-time clocks) 50 and 60 described in the third and fourth embodiments can be mounted on an electronic device that requires a time signal or a calendar function. That is, the temperature-compensated piezoelectric oscillator and the real-time clock can be mounted on an electronic device such as a computer or server that requires time management as a signal source of a clock signal for a clock, for example.

  When the electronic device has a sleep mode, the piezoelectric device outputs the correction value data and the intermediate value data from the correction value determination circuit 30 to compensate the temperature of the frequency temperature characteristics of the piezoelectric vibrator 20. The sensor 14, the A / D converter 16, and the storage unit 18 can be operated intermittently, and the power consumption of the electronic device can be reduced. In addition, when the electronic device is operated with a battery, the consumption of the battery can be delayed. If the piezoelectric device is a real-time clock, the electronic device can be used as a low power consumption sleep clock during the sleep mode.

  In this embodiment, an embodiment of a correction value determination circuit will be described. FIG. 8 is an explanatory diagram of a correction value determination circuit. The correction value determination circuit 30 according to the present embodiment is configured to input and output an 8-bit signal, but the number of bits is not limited to 8 bits. For example, a latch circuit may be used for the first storage unit 32, the second storage unit 34, and the third storage unit 40. The intermediate value calculation means 36 may be an adder circuit. Furthermore, the selection means 38 may be a three-state buffer.

It is a schematic explanatory drawing of a correction value determination circuit. It is a block diagram explaining a temperature compensation oscillation circuit. It is a figure explaining the timing of temperature compensation. It is a figure explaining the modification of the timing of temperature compensation. It is a schematic explanatory drawing of the correction value determination circuit of 2nd Embodiment. It is explanatory drawing of the piezoelectric device which concerns on 3rd Embodiment. It is explanatory drawing of the piezoelectric device which concerns on 4th Embodiment. It is explanatory drawing of a correction value determination circuit. It is explanatory drawing of the temperature compensation oscillation circuit which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ......... Temperature compensated oscillation circuit, 12 ......... Temperature measurement unit, 18 ......... Storage unit, 20 ......... Piezoelectric vibrator, 22 ......... Oscillation circuit, 30 ......... Correction value determination circuit, 32 ... ...... First storage unit, 34 ......... Second storage unit, 36 ......... Intermediate value calculation means, 38 ......... Selection means, 40 ......... Third storage unit, 42 ......... Control means, 44 ... ... delay means.

Claims (8)

The ambient temperature of the piezoelectric vibrator is intermittently measured by the temperature measurement unit, and the correction value data corresponding to the measured temperature is obtained from the correction value data stored in advance.
While adjusting the means for temperature compensation of the frequency temperature characteristics of the piezoelectric vibrator by delaying a predetermined time from the temperature measurement based on the correction value data,
From the obtained correction value data of the last two times, intermediate value data to be interpolated between them is obtained, and the means for temperature compensating the frequency temperature characteristics of the piezoelectric vibrator is adjusted based on the intermediate value data.
A temperature compensation method for a temperature compensated oscillation circuit.   2. The temperature compensation method for a temperature compensated oscillation circuit according to claim 1, wherein the means for compensating for temperature is adjusted based only on the correction value data. A temperature compensated oscillation circuit that outputs correction value data according to the ambient temperature of the piezoelectric vibrator and compensates the frequency temperature characteristics of the piezoelectric vibrator based on the correction value data,
A circuit for inputting the correction value data and outputting it as it is;
A circuit that inputs the first correction value data and the second correction value data, and obtains and outputs intermediate value data that interpolates between the correction value data;
Means for inputting and holding the correction value data or the intermediate value data, and delaying and outputting the data held in accordance with the temperature time constant of the piezoelectric vibrator;
A temperature-compensated oscillation circuit comprising:   4. The temperature compensated oscillation circuit according to claim 3, wherein one or more intermediate value data are output. A temperature measurement unit that outputs measurement data obtained by measuring the ambient temperature of the piezoelectric vibrator as a digital signal;
A storage unit for inputting the measurement data and outputting correction value data stored in advance corresponding to the measurement data;
A correction value determination circuit that inputs the correction value data and outputs the correction value data or intermediate value data;
An oscillation circuit connected to the piezoelectric vibrator that outputs an oscillation signal temperature-compensated according to the input correction value data or the intermediate value data;
The correction value determination circuit includes:
A first storage unit for inputting and holding the correction value data from the storage unit;
A second storage unit that is connected to a subsequent stage of the first storage unit, inputs the correction value data output from the first storage unit, and temporarily holds the correction value data;
The intermediate value is input to the correction value data output from the first storage unit and the correction value data output from the second storage unit, connected to the subsequent stage of the first storage unit and the second storage unit. Intermediate value calculating means for obtaining data;
A selector that is connected to the subsequent stage of the first storage unit and the intermediate value calculating means, inputs the correction value data and the intermediate value data, and outputs either one;
A third storage unit connected to the subsequent stage of the selection unit, holding the data output from the selection unit, and outputting the data held with delay in accordance with the temperature time constant of the piezoelectric vibrator; Prepared,
A temperature-compensated oscillation circuit characterized by the above.   6. A temperature-compensated oscillation circuit comprising a temperature-compensated oscillation circuit according to claim 3 and a clock circuit having at least a clock function connected thereto.   A piezoelectric device, wherein a piezoelectric vibrator is connected to the temperature compensated oscillation circuit according to claim 3.   An electronic apparatus comprising the piezoelectric device according to claim 7.

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