JP6339252B2 - Oscillation control device and oscillation device - Google Patents

Description

  The present invention relates to an oscillation control device and an oscillation device.

Conventionally, in an oscillation circuit that oscillates a vibrator, the oscillation frequency is adjusted by using a compensation circuit that compensates for temperature characteristics of the oscillation frequency of the vibrator. It has also been known to adjust the oscillation frequency of the vibrator in accordance with a control signal input from the outside while performing such a temperature compensation operation (see, for example, Patent Documents 1 and 2).
Patent Document 1 Japanese Patent Application Laid-Open No. 2010-219980 Patent Document 2 Japanese Patent Application Laid-Open No. 2010-278622

  However, even if the oscillation frequency of the vibrator is adjusted in this way, if an error such as an offset is included in the adjustment circuit or the like, it may be difficult to accurately adjust the oscillation frequency. When adjusting the oscillation frequency by comparing a control signal such as an external input voltage with a reference voltage, etc., if the control signal becomes substantially the same voltage as the reference voltage, unnecessary switching of the control operation occurs. The oscillation operation may become unstable.

  In the first aspect of the present invention, based on the temperature detection result of the temperature detection unit, a first control unit that generates a first control signal that controls the oscillation frequency of the vibrator, an encoder that generates a feedback signal, and a temperature A second control unit that generates a second control signal for controlling the oscillation frequency of the vibrator based on a temperature detection result of the detection unit, an external input signal input from the outside, and a feedback signal; a first control signal; 2 is provided with an oscillation circuit for setting the oscillation frequency of the vibrator on the basis of the control signal and a reference voltage generation unit for generating a reference voltage. The encoder compares the second control signal with the reference voltage to thereby generate a feedback signal. An oscillation control device is provided.

  In the second aspect of the present invention, the vibrator, the temperature detection unit for detecting the temperature of the vibrator, the input terminal for inputting an external input signal from the outside, and the oscillation control device of the first aspect are provided. An oscillation device is provided.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

1 shows a first configuration example of an oscillation device 1000 according to the present embodiment. A first example of temperature characteristics of the oscillation frequency of the vibrator 10 will be shown. The 2nd example of the temperature characteristic of the oscillation frequency of the vibrator | oscillator 10 is shown. The 3rd example of the temperature characteristic of the oscillation frequency of the vibrator | oscillator 10 is shown. The 2nd structural example of the oscillation apparatus 1000 which concerns on this embodiment is shown. An example of an oscillation frequency compensation result by the oscillation device 1000 of the second configuration example according to the present embodiment is shown. An example when an offset error occurs in the oscillation device 1000 of the second configuration example according to the present embodiment will be described. An example of the oscillation frequency which the oscillation apparatus 1000 which concerns on this embodiment outputs is shown. The structural example of the oscillation apparatus 2000 which concerns on this embodiment is shown. The structural example of the 1st control part 310 which concerns on this embodiment, the 2nd control part 320, and the encoder 340 is shown. An example of the oscillation frequency which the oscillation apparatus 2000 based on this embodiment outputs is shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 shows a first configuration example of an oscillation device 1000 according to the present embodiment. The oscillation device 1000 adjusts the oscillation frequency of the vibrator according to an input voltage or the like input from the outside while compensating for the temperature characteristic of the oscillation frequency of the vibrator. The oscillation device 1000 includes the vibrator 10, the temperature detection unit 20, the input terminal 32, the output terminal 34, the first capacitance control unit 110, the second capacitance control unit 120, and the oscillation circuit 200. The first capacitance control unit 110, the second capacitance control unit 120, and the oscillation circuit 200 function as the oscillation control device 100 that controls the oscillation of the vibrator 10.

  The vibrator 10 is an element that oscillates due to a piezoelectric effect that is deformed by application of an electric field. For example, the vibrator 10 is a crystal vibrator in which a crystal is provided between two electrodes. The oscillator 10 may be capable of adjusting the oscillation frequency according to the capacity of a circuit to be connected. The vibrator 10 may be formed by being cut in an orientation called AT. Note that the oscillation frequency of the vibrator 10 varies depending on the temperature of the vibrator 10. Further, the oscillation frequency of the vibrator 10 varies with time according to long-term operation. The oscillation device 1000 adjusts the oscillation frequency of such a vibrator 10.

  The temperature detection unit 20 detects the temperature of the vibrator 10. The temperature detection unit 20 may include a temperature sensor that detects the temperature around the vibrator 10. The temperature detection unit 20 may detect the temperature of the vibrator 10 in contact with the vibrator 10, or alternatively, may detect the temperature of the vibrator 10 in a non-contact manner. The oscillation device 1000 adjusts the oscillation frequency of the vibrator 10 according to the detection result of the temperature detection unit 20.

  An external input signal from the outside is input to the input terminal 32. Here, the external input signal is a control signal for adjusting the oscillation frequency of the vibrator 10. The external input signal is, for example, a control signal that corrects aging fluctuations associated with long-term operation of the vibrator 10. The external input signal may be a voltage signal or the like. In the present embodiment, such control for correcting the secular variation of the vibrator 10 is assumed to be AFC (Auto Frequency Control).

  The output terminal 34 outputs the frequency signal adjusted by the oscillation device 1000 to the outside. That is, the frequency signal output from the output terminal 34 is a frequency signal adjusted by temperature compensation and AFC.

  The first capacitance control unit 110 controls the capacitance of a circuit connected to the vibrator 10 based on the temperature detection result of the temperature detection unit 20. The first capacitance control unit 110 controls the capacitance of the circuit connected to the vibrator 10 and adjusts the oscillation frequency of the vibrator 10. The first capacitance control unit 110 controls the capacitance of the circuit so as to compensate the temperature characteristic of the oscillation frequency of the vibrator 10. The first capacity control unit 110 may increase or decrease the capacity using a control signal based on a predetermined function according to the temperature detection result of the temperature detection unit 20.

  The second capacity control unit 120 controls the capacity of a circuit connected to the vibrator 10 based on an external input signal input from the outside. The second capacitance control unit 120 adjusts the oscillation frequency of the vibrator 10 by controlling the capacity of a circuit connected to the vibrator 10. The second capacity control unit 120 controls the capacity of the circuit so as to adjust the oscillation frequency of the vibrator 10 based on AFC control. The second capacity control unit 120 may increase or decrease the capacity using a control signal based on a predetermined function in accordance with an external input signal input from the input terminal 32.

  The oscillation circuit 200 is connected to the vibrator 10, oscillates the vibrator 10 at the oscillation frequency, and outputs an oscillated frequency signal. The oscillation circuit 200 includes a first variable capacitor 210, a second variable capacitor 220, a third variable capacitor 230, a fourth variable capacitor 240, a resistor 250, and an amplifier 260.

  The first variable capacitance unit 210, the second variable capacitance unit 220, the third variable capacitance unit 230, and the fourth variable capacitance unit 240 include elements that change the capacitance according to an input electric signal. In the present embodiment, the first variable capacitance unit 210, the second variable capacitance unit 220, the third variable capacitance unit 230, and the fourth variable capacitance unit 240 include elements or circuits that change the capacitance according to the input voltage. For example, it includes a varactor diode, a ferroelectric capacitor, a transistor circuit, and / or a MEMS element.

  The first variable capacitor unit 210 and the second variable capacitor unit 220 are connected in parallel between one terminal of the vibrator 10 and the reference potential. Here, the reference potential may be a ground potential. By changing the capacitance of at least one of the first variable capacitance unit 210 and the second variable capacitance unit 220, the capacitance between one terminal of the vibrator 10 and the reference potential is adjusted. FIG. 1 illustrates an example in which the first capacity control unit 110 controls the capacity of the first variable capacity unit 210, and the second capacity control unit 120 controls the capacity of the second variable capacity unit 220.

  The third variable capacitance unit 230 and the fourth variable capacitance unit 240 are connected in parallel between the other terminal of the vibrator 10 and the reference potential. By changing the capacitance of at least one of the third variable capacitance unit 230 and the fourth variable capacitance unit 240, the capacitance between the other terminal of the vibrator 10 and the reference potential is adjusted. FIG. 1 illustrates an example in which the first capacity control unit 110 controls the capacity of the third variable capacity unit 230, and the second capacity control unit 120 controls the capacity of the fourth variable capacity unit 240.

  The resistor 250 and the amplifier 260 are connected in parallel between one terminal and the other terminal of the vibrator 10. That is, the resistor 250 connects between the input and output of the amplifier 260 and operates as a feedback resistor. The amplifying unit 260 may be an inverter that inverts and amplifies an input signal and outputs it. The amplifier 260 outputs a part of the amplified signal as a frequency signal of the oscillation circuit. The first to fourth variable capacitance elements, the resistor 250, and the amplification unit 260 described above operate as an oscillation circuit that oscillates the vibrator 10. Note that the oscillation circuit 200 may further include a current limiting resistor, an amplifier circuit that amplifies the frequency signal, and the like.

Incidentally, the resonance frequency of the vibrator 10 and f _r, when the difference between the actual oscillating frequency and the frequency δf, δf / f _r is expressed by the following equation. Here, C _A and C _B are constants of capacitance components included in an equivalent circuit determined by the vibrator 10, and C _L is a constant of load capacitance connected to both ends of the vibrator 10. That is, by increasing (decreasing) the load capacity, the oscillation frequency of the vibrator 10 can be adjusted to the low frequency side (to the high frequency side).
(Equation 1)
δf / f _r = 0.5 · C _A / {C _B · (1 + C _L / C _B )}

Note that _CL is expressed by the following equation, for example, where C ₁ is a capacitor connected to one end of the vibrator 10 and C ₂ is a capacitor connected to the other end. Here, C _S is a parasitic capacitance of the oscillation circuit 200.
(Equation 2)
C _L = C ₁ · C ₂ / (C ₁ + C ₂ ) + C _S

That is, the oscillation device 1000, for example, by adjusting the capacitance of the first variable capacitance section 210 and / or the second variable capacitance section 220, changes the value of _{C 1,} to control the oscillation frequency. In this case, the oscillation device 1000 adjusts the capacity of the third variable capacitance section 230 and / or fourth variable capacitance section 240, changes the value of C _2, controls the oscillation frequency. As an example, the oscillation device 1000 decreases the value of C ₁ and / or C ₂ to adjust the oscillation frequency to the high frequency side. Further, for example, the oscillation device 1000 increases the value of C ₁ and / or C ₂ to adjust the oscillation frequency to the low frequency side.

  As described above, the oscillation device 1000 performs frequency adjustment by temperature compensation and frequency adjustment by AFC, and outputs a frequency signal having a stable oscillation frequency. Here, the temperature characteristics of the oscillation frequency of the vibrator 10 will be described next.

FIG. 2 shows a first example of temperature characteristics of the oscillation frequency of the vibrator 10. In FIG. 2, the horizontal axis represents temperature, and the vertical axis represents oscillation frequency. A curve A in FIG. 2 shows an example of a temperature characteristic of the AT-cut vibrator 10 and has a characteristic that can be approximated by a cubic function with respect to the temperature. For example, the oscillation frequency of the vibrator 10 having the reference frequency f _{0 at} the reference temperature T ₀ varies in the range of f ₀ −f ₁ to f ₀ + f ₁ in the temperature range of T ₀ −ΔT to T ₀ + ΔT.

By obtaining such temperature characteristics of the vibrator 10 by measurement or the like in advance, the oscillation device 1000 can compensate for fluctuations in the oscillation frequency of the vibrator 10. For example, the oscillation device 1000 uses a curve B having a reverse characteristic of the curve A, and adds a frequency correction value corresponding to a point on the curve B with respect to the detected temperature. For example, the first capacity control unit 110 controls the capacity of the first variable capacity unit 210 and / or the third variable capacity unit 230, and the frequency f _B on the curve B with respect to the temperature T detected by the temperature detection unit 20 ( The oscillation frequency is changed by a difference frequency between T) and the frequency f _A (T) on the curve A. Thus, the oscillation device 1000 can stabilize the oscillation frequency of the vibrator 10 at a substantially constant frequency as shown by the straight line C.

  In addition to this, the oscillation device 1000 changes the oscillation frequency of the vibrator 10 to a frequency according to AFC control. However, when the oscillation frequency of the vibrator 10 is changed, the temperature characteristics of the vibrator 10 become different from the curve A shown in FIG. 2, so that even if the oscillation device 1000 uses the curve B to change the oscillation frequency. , And cannot be stabilized like the straight line C.

FIG. 3 shows a second example of temperature characteristics of the oscillation frequency of the vibrator 10. In FIG. 3, the horizontal axis indicates the temperature, and the vertical axis indicates the oscillation frequency. FIG. 3 shows an example in which the oscillation device 1000 increases the oscillation frequency of the vibrator 10 by Δf in accordance with AFC control. FIG. 3 shows an example of the resonator 10 in which the second capacitance control unit 120 reduces the capacitance of the second variable capacitance unit 220 and / or the fourth variable capacitance unit 240 and oscillates at the reference frequency f ₀ . The result of changing the oscillation frequency by + Δf is shown. An example of the temperature characteristic of the vibrator 10 in this case is indicated by a curve A ′. Even in this case, the temperature characteristic of the vibrator 10 can be approximated by a cubic function, and is substantially the same as the characteristic obtained by shifting the curve A shown in FIG. 2 by + Δf.

Here, for example, consider a case where the second capacity control unit 120 reduces the capacity of the second variable capacity unit 220. Since the capacitance C ₁ at one end of the vibrator 10 is a combined capacitance of the first variable capacitance unit 210 and the second variable capacitance unit 220, when the second variable capacitance unit 220 becomes small, the capacitance of the first variable capacitance unit 210 increases or decreases. effect on the value of the capacitance C ₁ becomes large. Therefore, if the first capacitance control unit 110 changes the capacitance of the first variable capacitance unit 210 to compensate for the temperature characteristics of the vibrator 10 according to the adjustment amount before the AFC control, the frequency adjustment amount is excessive. turn into.

Capacitance C ₂ of the other end of the vibrator 10, since the combined capacitance of the third variable capacitance section 230 and the fourth variable capacitance section 240, when the second capacity control section 120, which has a small capacity of the fourth variable capacitance section 240 Similarly, even if the first capacity control unit 110 changes the capacity of the third variable capacity unit 230 according to the adjustment amount before the AFC control, the frequency adjustment becomes excessive. A curve B ′ in FIG. 3 indicates a frequency when the first capacitance control unit 110 adjusts the capacitance of the first variable capacitance unit 210 and / or the third variable capacitance unit 230 using the adjustment amount before the AFC control. An example of the adjustment amount is shown.

As described above, the frequency adjustment amount of the first capacitance control unit 110 is f ₀ + Δf−f ₂ to T ₀ + Δf + f ₂ (f ₁ <f ₂ ) in the temperature range from T ₀ −ΔT to T ₀ + ΔT, and vibrations. The variation of the oscillation frequency of the child 10 fluctuates more than ± f ₁ . Therefore, when the oscillation device 1000 changes the oscillation frequency to the high frequency side by AFC control and compensates the temperature of the vibrator 10, the oscillation device 1000 excessively adjusts the frequency as shown by the curve C ′ and is stable at a substantially constant frequency. It becomes impossible to make it.

FIG. 4 shows a third example of the temperature characteristic of the oscillation frequency of the vibrator 10. In FIG. 4, the horizontal axis represents temperature, and the vertical axis represents oscillation frequency. FIG. 4 shows an example in which the oscillation device 1000 reduces the oscillation frequency of the vibrator 10 by Δf in accordance with AFC control. FIG. 4 shows an example of the vibrator 10 in which the second capacitance control unit 120 increases the capacitance of the second variable capacitance unit 220 and / or the fourth variable capacitance unit 240 and oscillates at the reference frequency f ₀ . The result of changing the oscillation frequency by −Δf is shown. An example of the temperature characteristic of the vibrator 10 in this case is indicated by a curve A ″. In this case as well, the temperature characteristic of the vibrator 10 can be approximated by a cubic function, and the curve A shown in FIG. 2 is shifted by −Δf. The characteristics are almost the same as those described above.

As described with reference to FIG. 2, the capacitance C ₁ at one end of the vibrator 10 is a combined capacitance of the first variable capacitance unit 210 and the second variable capacitance unit 220. Therefore, when the second variable capacitance unit 220 increases, the first variable capacitance unit 220 increases. Effect of changes in capacitance of the capacitor portion 210 gives the value of the capacitance C ₁ becomes smaller. Therefore, if the first capacitance control unit 110 changes the capacitance of the first variable capacitance unit 210 using the adjustment amount before the AFC control to compensate for the temperature characteristics of the vibrator 10, the frequency adjustment amount is insufficient. End up. Similarly, even if the first capacity control unit 110 changes the capacity of the third variable capacity unit 230 using the adjustment amount before the AFC control, the frequency adjustment amount is insufficient.

A curve B ″ in FIG. 4 indicates a frequency when the first capacitance control unit 110 adjusts the capacitance of the first variable capacitance unit 210 and / or the third variable capacitance unit 230 using the adjustment amount before the AFC control. shows an example of the adjustment amount. Thus, the frequency adjustment amount of the first capacity control section _110, in the temperature range from _{T 0 -ΔT T 0 + ΔT,} T 0 -Δf + f 3 becomes from _f 0 _{-Δf-f 3} (F ₁ > f ₃ ), which fluctuates smaller than the fluctuation range ± f ₁ of the oscillation frequency of the vibrator 10. Therefore, the oscillation device 1000 changes the oscillation frequency to the low frequency side by AFC control, When temperature compensation is performed, the oscillation frequency is insufficiently adjusted as shown by the curve C ′, and cannot be stabilized at a substantially constant frequency.

  Note that when the second capacitance control unit 120 reduces the capacitance of the second variable capacitance unit 220 and / or the fourth variable capacitance unit 240 by AFC control, the capacitance of the entire oscillation circuit is reduced. Therefore, when the first capacitance control unit 110 changes the capacitance of the first variable capacitance unit 210 and / or the third variable capacitance unit 230, the rate of change of the capacitance of the entire oscillation circuit becomes larger than before the AFC control. .

  On the other hand, when the second capacity control unit 120 increases the capacity of the second variable capacity part 220 and / or the fourth variable capacity part 240 by AFC control, the capacity of the entire oscillation circuit increases. Therefore, when the first capacitance control unit 110 changes the capacitance of the first variable capacitance unit 210 and / or the third variable capacitance unit 230, the rate of change of the capacitance of the entire oscillation circuit becomes smaller than that before the AFC control. .

  That is, even if the amount of change in the capacity due to temperature compensation of the oscillation device 1000 is the same, the amount of change in frequency due to the temperature compensation differs depending on the direction of change in the oscillation frequency by AFC control. For example, the amplitude value of the temperature compensation result when the oscillation frequency of the vibrator 10 is changed by + Δf by AFC control (that is, the curve C ′) is the temperature compensation result when the oscillation frequency of the vibrator 10 is changed by −Δf (ie, Therefore, in order to stabilize the oscillation frequency to a substantially constant frequency by temperature compensation after executing the AFC control, the amplitude value of the curve C ″) is increased according to the direction of change of the oscillation frequency of the AFC control. Thus, the compensation values of different frequencies must be used, and an oscillation device that performs such compensation operation will be described below.

  FIG. 5 shows a second configuration example of the oscillation device 1000 according to the present embodiment. In the oscillation device 1000 of the second configuration example, components that are substantially the same as the operations of the oscillation device 1000 of the first configuration example shown in FIG. The oscillation device 1000 of the second configuration example further includes a reference voltage input terminal 36, a comparison unit 130, and a third capacitance control unit 140. The first capacitance control unit 110, the second capacitance control unit 120, the comparison unit 130, the third capacitance control unit 140, and the oscillation circuit 200 function as the oscillation control device 100 that controls the oscillation of the vibrator 10.

A predetermined reference voltage is input to the reference voltage input terminal 36. The reference voltage is substantially equal to the external input signal that causes the second capacitance control unit 120 to set the oscillation frequency of the vibrator 10 to the reference frequency f ₀ when the temperature variation of the vibrator 10 is compensated (or not considered). Good.

That is, for example, when the temperature variation is compensated and the external input signal is larger than the reference voltage, the second capacitance control unit 120 sets the capacitance of the second variable capacitance unit 220 and / or the fourth variable capacitance unit 240. and small, it changes the oscillation frequency of the oscillator 10 to a frequency greater than the reference frequency f _0. In addition, when the external input signal is smaller than the reference voltage, the second capacitance control unit 120 increases the capacitance of the second variable capacitance unit 220 and / or the fourth variable capacitance unit 240 to increase the oscillation frequency of the vibrator 10. to change to a smaller frequency than the reference frequency f _0. Note that the oscillation device 1000 may generate a reference voltage internally, and in this case, the reference voltage input terminal 36 may not be provided.

  The comparison unit 130 compares the external input signal and the reference voltage. For example, the comparison unit 130 outputs a high voltage when the external input signal is equal to or higher than the reference voltage, and outputs a low voltage when the external input signal is lower than the reference voltage. The comparison unit 130 may be an encoder that outputs one of a predetermined high voltage and low voltage according to an external input signal and a reference voltage. The comparison unit 130 includes a comparator as an example.

  The third capacitance control unit 140 controls the capacitance of the circuit connected to the vibrator 10 based on the comparison result between the external input signal and the reference voltage and the control signal output from the first capacitance control unit 110. The third capacity control unit 140 adjusts the oscillation frequency of the vibrator 10 by controlling the capacity of a circuit connected to the vibrator 10. For example, the third capacitance control unit 140 may compensate the first variable capacitance unit 210 and / or the first capacitance control unit 110 so that the first capacitance control unit 110 further compensates for the characteristic that the temperature characteristic of the oscillation frequency of the vibrator 10 cannot be compensated. 3 Control the variable capacitor 230. Instead, the third capacity control unit 140 may control the second variable capacity unit 220 and / or the fourth variable capacity unit 240.

  The third capacity control unit 140 switches a control circuit or a control operation for increasing or decreasing the capacity, for example, according to the comparison result between the external input signal and the reference voltage. In this case, the control circuit of the third capacity control unit 140 may generate a control signal for increasing or decreasing the capacity using a control signal amplified with a predetermined gain (gain). For example, when the external input signal is equal to or higher than the reference voltage, the third capacitance control unit 140 outputs a control signal amplified with a positive adjustment gain, and when the external input signal is less than the reference voltage, the negative adjustment gain. The control signal amplified in step 1 is output.

  Instead, the third capacity control unit 140 may increase or decrease the capacity using a control signal obtained by multiplying a control signal output from the first capacity control unit 110 by a predetermined coefficient. The third capacity control unit 140 increases or decreases the capacity using, for example, a control signal obtained by multiplying a control signal output from the first capacity control unit 110 by a predetermined coefficient. The coefficient used by the third capacity control unit 140 may be a coefficient corresponding to the magnitude of the control signal output from the first capacity control unit 110 and the comparison result between the external input signal and the reference voltage. For example, the third capacity control unit 140 switches the coefficient according to the comparison result between the external input signal and the reference voltage.

The third capacity control unit 140 changes the capacity of the first variable capacity unit 210 and / or the third variable capacity unit 230 according to the generated control signal. Oscillator 1000 in the second configuration example, by using such a third capacity control section 140, according to the change direction from the reference frequency f ₀ of the oscillation frequency by AFC control, change of the oscillation frequency of the oscillator 10 Different amounts can be compensated. Next, the compensation operation of the oscillation device 1000 of the second configuration example will be described.

FIG. 6 shows an example of the compensation result of the oscillation frequency by the oscillation device 1000 of the second configuration example according to the present embodiment. FIG. 6 shows a graph in which the horizontal axis represents temperature and the vertical axis represents the oscillation frequency of the vibrator 10, an external input signal corresponding to the frequency of the graph, and a graph of circuit gain corresponding to the external input signal. FIG. 6 shows an example in which an external input signal holding the reference frequency f ₀ is used as a reference voltage. In this case, a reference voltage external input signal and substantially the same voltage, when the first capacity control section 110 compensates for the temperature characteristics of the vibrator 10, the oscillation frequency of the vibrator 10, the reference frequency f ₀ is substantially the same And stabilize.

  Further, the second capacitance control unit 120 shifts the oscillation frequency of the vibrator 10 to the high frequency side in response to the external input signal becoming larger than the reference voltage by the AFC control. In this case, the first capacitance control unit 110 compensates for the temperature characteristics of the vibrator 10, but as described with reference to FIG. 3, the amount of frequency change due to temperature compensation becomes excessive.

  The comparison unit 130 compares the external input signal and the reference voltage, and outputs a high voltage indicating that the external input signal is high. The third capacitance control unit 140 adjusts the oscillation frequency of the vibrator 10 using the positive adjustment gain according to the high voltage of the comparison result. For example, the third capacity control unit 140 amplifies the control signal output from the first capacity control unit 110 with the positive adjustment gain. The temperature characteristic indicated by the curve C ′ in FIG. 3 is a result of excessive compensation by the first capacitance control unit 110 using a predetermined function. Therefore, the first capacitance control unit 110 corrects the excessive compensation. The positive adjustment gain may be determined in advance so as to have the reverse characteristic of the control signal output by 110.

  Accordingly, the third capacitance control unit 140 adjusts the first variable capacitance unit 210 and / or the third variable capacitance unit 230 so that the temperature characteristic indicated by the curve C ′ in FIG. Can do. That is, the oscillation device 1000 according to the present embodiment compensates for temperature characteristics caused by the change of the third capacitance control unit 140 even when the second capacitance control unit 120 changes the oscillation frequency of the vibrator 10 by AFC control. Thus, the oscillation frequency of the vibrator 10 can be compensated to a substantially constant temperature characteristic.

FIG. 6 shows that when the second capacitance control unit 120 shifts the oscillation frequency by + Δf ₁ , + Δf ₂ , and + Δf ₃ , the third capacitance control unit 140 uses the positive adjustment gain to set the oscillation frequency to f Examples of stabilizing to ₀ + Δf ₁ , f ₀ + Δf ₂ , and f ₀ + Δf ₃ , respectively, are shown as “first positive adjustment”, “second positive adjustment”, and “third positive adjustment”. It should be noted that the result of excessive compensation by the first capacity control unit 110 is indicated by a dotted line curve, the frequency adjustment amount of the third capacity control unit 140 is indicated by a one-dot chain line curve, and their synthesis, that is, the adjustment result is indicated by a solid line. Respectively.

For example, the example of “third positive side adjustment” indicates a result of the second capacitance control unit 120 shifting the oscillation frequency of the vibrator 10 by + Δf ₃ . That is, the result of excessive compensation by the first capacitance control unit 110 is the curve D, the frequency adjustment amount of the third capacitance control unit 140 that compensates the temperature characteristic of the curve D is the curve E, and the compensation result is the straight line F. is there.

  Similarly, the second capacitance control unit 120 shifts the oscillation frequency of the vibrator 10 to the low frequency side in response to the external input signal becoming smaller than the reference voltage by the AFC control. In this case, the first capacitance control unit 110 compensates for the temperature characteristics of the vibrator 10, but as described with reference to FIG. 4, the amount of frequency change due to temperature compensation is insufficient.

  The comparison unit 130 compares the external input signal and the reference voltage, and outputs a low voltage indicating that the external input signal is low. The third capacitance control unit 140 adjusts the oscillation frequency of the vibrator 10 using the negative adjustment gain according to the low voltage of the comparison result. For example, the third capacity control unit 140 amplifies the control signal output from the first capacity control unit 110 with a negative adjustment gain. Accordingly, even if the second capacitance control unit 120 changes the oscillation frequency of the vibrator 10 by the AFC control, the oscillation device 1000 compensates for the temperature characteristic generated by the change by the third capacitance control unit 140, and the vibrator Ten oscillation frequencies can be compensated for substantially constant temperature characteristics.

FIG. 6 shows that when the second capacitance control unit 120 shifts the oscillation frequency by −Δf ₁ , −Δf ₂ , and −Δf ₃ , the third capacitance control unit 140 uses the negative adjustment gain to oscillate. Examples of stabilizing the frequency to f ₀ −Δf ₁ , f ₀ −Δf ₂ , and f ₀ −Δf ₃ , respectively, “first negative adjustment”, “second negative adjustment”, and “third negative adjustment” ". In addition, the result of insufficient compensation by the first capacity control unit 110 is indicated by a dotted line curve, the frequency adjustment amount of the third capacity control unit 140 is indicated by a one-dot chain line, and their synthesis, that is, the adjustment result is indicated by a solid line. Each is shown.

For example, the example of “third negative adjustment” shows a result of the second capacitance control unit 120 shifting the oscillation frequency of the vibrator 10 by −Δf ₃ . That is, the result of insufficient compensation of the first capacity control unit 110 is the curve D, the frequency adjustment amount of the third capacity control unit 140 that compensates the temperature characteristic of the curve D is the curve E, and the compensation result is the straight line F. is there. As described above, the oscillation device 1000 of the second configuration example can execute an appropriate compensation operation according to the frequency variation direction by the AFC control.

  However, when such an oscillation device 1000 is actually formed by an electronic circuit or the like, an offset error occurs in the second capacitance control unit 120 and the third capacitance control unit 140 and the like, and a control signal for controlling the capacitance of the oscillation circuit 200 The offset error may be superimposed on the. Therefore, it is conceivable to adjust the external input signal so as to cancel the offset error. However, since the oscillation device 1000 of the second configuration example switches the temperature compensation operation according to the result of comparing the external input signal and the reference voltage, the oscillation frequency of the vibrator 10 may be stabilized depending on the magnitude of the offset error. The case where it cannot be made occurs.

As an example, when the frequency shift amount corresponding to the offset error generated inside the oscillation device 1000 is Δf ₄ , the external system uses the external input signal obtained by subtracting the signal component corresponding to Δf ₄ as the shift amount. 1000. Therefore, since the external input signal is shifted according to the offset error, the temperature compensation operation switching operation may not be executed normally.

  FIG. 7 shows an example when an offset error occurs in the oscillation device 1000 of the second configuration example according to the present embodiment. As in FIG. 6, FIG. 7 is a graph in which the horizontal axis represents temperature and the vertical axis represents the oscillation frequency of the vibrator 10, the external input signal corresponding to the frequency of the graph, and the circuit gain corresponding to the external input signal. The graph is shown.

  FIG. 7 shows an example in which an external input signal that cancels out the offset error is supplied in response to the occurrence of the offset error in the second capacitance control unit 120 and / or the third capacitance control unit 140. That is, the control of the capacity of the oscillation circuit 200 is not affected by the offset error, and the oscillation frequency of the vibrator 10 is changed to a frequency corresponding to the frequency shift amount corresponding to the external input signal.

For example, when the frequency shift amount is + Δf ₁ and the frequency shift amount corresponding to the offset error is + Δf ₄ , the external input signal is a signal corresponding to the frequency f ₀ + Δf ₁ −Δf ₄ . Accordingly, when the offset error is superimposed, the frequency shift amount is + Δf _1, and the oscillation circuit 200 shifts the oscillation frequency of the vibrator 10 to the high frequency side (positive side). Here, when Δf ₁ −Δf ₄ > 0, the output of the comparison unit 130 becomes a high voltage, and the third capacitance control unit 140 uses the positive adjustment gain. Can be stabilized at f ₀ + Δf ₁ .

However, when Δf ₁ −Δf ₄ <0, the output of the comparison unit 130 is a low voltage, and thus the oscillation circuit 200 shifts the oscillation frequency of the vibrator 10 to the high frequency side (positive side). The third capacitance control unit 140 uses the negative adjustment gain according to the external input signal. Therefore, the oscillation device 1000 cannot compensate for the temperature characteristics of the vibrator 10. In addition, since the third capacitance control unit 140 changes the oscillation frequency of the vibrator 10 using a characteristic similar to the temperature characteristic to be corrected, the characteristics of the insufficient compensation result by the first capacitance control unit 110 are further improved. It may make it worse.

FIG. 7 shows an example in which the frequency shift amount corresponding to the offset error is + Δf ₄ and the absolute value is larger than + Δf ₁ (Δf ₁ <Δf ₄ ). In this case, when the frequency shift amount corresponding to the external input signal is larger than 0 and smaller than Δf ₄ , the third capacitance control unit 140 uses the negative adjustment gain, while the oscillation circuit 200 includes the vibrator 10. The oscillation frequency is shifted to the high frequency side (positive side). Therefore, the oscillation device 1000 cannot stabilize the oscillation frequency of the vibrator 10 in a frequency range that is larger than the reference frequency f ₀ and less than + Δf ₄ .

  In addition to this, when the oscillation device 1000 is actually formed by an electronic circuit or the like, the oscillation device 1000 may fluctuate the oscillation frequency of the vibrator 10 when the external input signal becomes a value close to the reference voltage. There is. That is, since the comparison unit 130 compares two substantially identical potentials, either the high voltage or the low voltage is output unstable, and the oscillation circuit 200 determines the oscillation frequency of the vibrator 10. Fluctuating chattering occurs.

  FIG. 8 shows an example of an oscillation frequency output from the oscillation device 1000 according to this embodiment. In FIG. 8, the horizontal axis represents time, and the vertical axis represents the oscillation frequency corresponding to the external input signal. FIG. 8 shows an example in which the external input signal changes over time, and the oscillation device 1000 outputs an oscillation frequency corresponding to the change in the external input signal. As described with reference to FIGS. 1 to 6, the oscillation device 1000 can oscillate the vibrator 10 at an oscillation frequency corresponding to an external input signal.

However, when the external input signal has substantially the same value as the reference voltage, the oscillation device 1000 changes the oscillation frequency. In particular, when noise or the like is superimposed on an external input signal, the oscillation frequency may react sensitively to noise fluctuations. For example, in the period from time t ₃ to t _{4 and in} the period from time t ₅ to t ₆ , the oscillation device 1000 generates chattering of the oscillation frequency. As described above, the oscillation device 1000 of the second configuration example has a case where the temperature characteristic cannot be compensated and a case where the output frequency fluctuates depending on the magnitude of the external input signal.

  Thus, the oscillation device 2000 according to the present embodiment compensates for temperature characteristics and prevents fluctuations in the output frequency regardless of the magnitude of the external input signal. FIG. 9 shows a configuration example of the oscillation device 2000 according to the present embodiment. In the oscillating device 2000, the same reference numerals are given to substantially the same operations as those of the oscillating device 1000 of the first configuration example shown in FIG.

  The oscillation device 2000 includes a vibrator 10, a temperature detection unit 20, an input terminal 32, an output terminal 34, an oscillation circuit 200, a first control unit 310, a second control unit 320, and a reference voltage generation unit 330. And an encoder 340. The vibrator 10, the temperature detection unit 20, the input terminal 32, and the output terminal 34 have been described with reference to FIG. Note that the oscillation circuit 200, the first control unit 310, the second control unit 320, the reference voltage generation unit 330, and the encoder 340 function as the oscillation control device 300 that controls the oscillation of the vibrator 10.

  The first control unit 310 generates a first control signal for controlling the oscillation frequency of the vibrator 10 based on the temperature detection result of the vibrator 10. The first control unit 310 controls the capacity of a circuit connected to the vibrator 10 and adjusts the oscillation frequency of the vibrator 10. For example, the first control unit 310 transmits a first control signal to the first capacitance variable unit and / or the third capacitance variable unit, and compensates for the temperature characteristics of the oscillation frequency of the vibrator 10. To control the oscillation frequency. The first controller 310 may perform substantially the same operation as that of the first capacity controller 110 described in FIG.

  The second control unit 320 generates a second control signal for controlling the oscillation frequency of the vibrator 10 based on the temperature detection result of the vibrator 10, an external input signal input from the outside, and a feedback signal from the encoder 340. To do. The second controller 320 receives feedback of the comparison result between the output second control signal and the reference voltage, and adjusts the output second control signal in accordance with the temperature detection result. The second control unit 320 generates a second control signal so as to stably oscillate the vibrator 10 at an oscillation frequency based on AFC control.

  For example, the second control unit 320 transmits the second control signal to the second capacitance variable unit and / or the fourth capacitance variable unit, changes the respective capacitances, and changes the temperature characteristics of the oscillation frequency of the vibrator 10. The oscillation frequency is controlled while compensating. As described in FIG. 6, the second control unit 320 selects either the positive adjustment gain or the negative adjustment gain, and amplifies the external input signal with the selected gain to generate the second control signal. You can do it.

The reference voltage generation unit 330 generates a reference voltage. The reference voltage generation unit 330 may generate the reference voltage described with reference to FIGS. That is, FIG. 5 shows an example in which a reference voltage is input from the reference voltage input terminal 36, and FIG. 9 shows an example in which the reference voltage is generated inside the oscillation device 2000. Here, when the first control unit 310 compensates the temperature characteristic of the vibrator 10 and stabilizes the oscillation frequency of the vibrator 10 to be substantially the same as the reference frequency f ₀ , the oscillation frequency of the vibrator 10 is stabilized. Is a reference voltage.

  The encoder 340 generates a feedback signal. The encoder 340 generates a feedback signal by comparing the second control signal and the reference voltage. The encoder 340 outputs digital data indicating the difference between the reference voltage and the second control signal. The encoder 340 may convert the digital data based on the comparison result between the difference between the reference voltage and the second control signal and the threshold value. For example, the encoder 340 outputs a high voltage when the difference between the external input signal and the reference voltage is 0 or more, and outputs a high voltage when the difference is less than 0. In this case, the encoder 340 may perform substantially the same operation as the comparison unit 130 illustrated in FIG. As an example, the encoder 340 includes a comparator. Further, the threshold level of the encoder 340 may have hysteresis. An example in which the threshold level has hysteresis will be described later.

  The oscillation circuit 200 sets the oscillation frequency of the vibrator 10 based on the first control signal and the second control signal. The oscillation circuit 200 includes a first variable capacitor 210, a second variable capacitor 220, a third variable capacitor 230, a fourth variable capacitor 240, a resistor 250, and an amplifier 260. The oscillation circuit 200 sets the oscillation frequency of the vibrator 10 based on the capacitances of the first variable capacitance unit 210, the second variable capacitance unit 220, the third variable capacitance unit 230, and the fourth variable capacitance unit 240.

  The first variable capacitance unit 210 and / or the third variable capacitance unit 230 changes the capacitance value based on the first control signal. The second variable capacitance unit 220 and / or the fourth variable capacitance unit 240 changes the capacitance value based on the second control signal. The operations of the first variable capacitor 210, the second variable capacitor 220, the third variable capacitor 230, the fourth variable capacitor 240, the resistor 250, and the amplifier 260 have been described with reference to FIG. Description is omitted.

  The oscillation device 2000 according to the present embodiment described above changes the oscillation frequency of the vibrator 10 using the first control signal generated by the first control unit 310, similarly to the oscillation device 1000 shown in FIG. Then, the second control signal generated by the second control unit 320 is used to further change the oscillation frequency of the vibrator 10 to compensate for the component that the first control unit 310 could not compensate for the temperature fluctuation of the vibrator 10. And stabilize.

  The second control unit 320 according to the above-described embodiment performs a feedback operation to generate a second control signal. For example, the second control unit 320 generates a second control signal in accordance with an external input signal by AFC control. The second control unit 320 receives digital data indicating a difference between the reference voltage output from the encoder 340 and the second control signal as a feedback signal. That is, the second control unit 320 generates the next second control signal using either the positive adjustment gain or the negative adjustment gain according to the comparison result of the encoder 340. Next, the first control unit 310 and the second control unit 320 will be described.

  FIG. 10 shows a configuration example of the first control unit 310, the second control unit 320, and the encoder 340 according to the present embodiment. The first control unit 310 generates a first control signal based on a predetermined function. Since the first control signal compensates for the temperature characteristic that is mainly a cubic function with the reference temperature as the origin, it may have a temperature-voltage characteristic with a cubic function with the reference temperature as the origin. That is, the first control unit 310 may generate a first control signal based on a cubic function with the reference temperature as the origin. The first controller 310 may generate a first control signal based on the sum of odd-order functions such as a linear function, a quintic function, and a seventh-order function with the reference temperature as the origin. Thereby, the first control unit 310 can compensate the temperature characteristic of the vibrator 10 more precisely.

  10, the first control unit 310 includes an n-order component generation unit 350 including a primary component generation unit 351, a secondary component generation unit 352, and a tertiary component generation unit 353, and the temperature detection result of the vibrator 10 An example in which an nth-order temperature-voltage characteristic with the reference temperature as the origin is generated according to FIG. The order n of the temperature-voltage characteristic is preferably a natural number of 1 or more. The nth-order component generation unit 350 may further include a generation unit that generates a component having a temperature-voltage characteristic of the fourth or higher order. Instead of this, the order n of the temperature-voltage characteristic may be an odd number of 1 or more.

  In addition, the first control unit 310 includes a first addition unit 360 that adds n-th temperature voltage characteristics, and the addition result of the first addition unit 360 is used as a first control signal. The first control signal is preferably a reverse characteristic of the temperature characteristic of the vibrator 10. As described above, the first controller 310 can compensate for the temperature characteristics of the vibrator 10 more precisely by adding the higher-order temperature voltage characteristics to generate the first control signal.

  Similarly to the first control unit 310, the second control unit 320 includes an n-order component generation unit 370 including a primary component generation unit 371, a secondary component generation unit 372, a tertiary component generation unit 373,. Have. In addition, the second control unit 320 includes a second addition unit 380 and an amplification unit 390. The n-order component generation unit 370 outputs temperature voltage characteristics corresponding to the temperature detection result of the temperature detection unit 20 and the comparison result of the encoder 340, respectively. The order n of the temperature voltage is preferably a natural number of 1 or more.

  As described above, the second control unit 320 can compensate for the temperature characteristics of the vibrator 10 more precisely by adding more orders of temperature voltage characteristics to generate the second control signal. In addition, even when a minute nonlinear component or the like is generated by the first control unit 310 compensating the temperature characteristics of the vibrator 10, the second control unit 320 uses a higher-order temperature-voltage characteristic. The temperature characteristics of the vibrator 10 can be compensated precisely. Such a minute nonlinear component or the like may have an even-order characteristic, and the second controller 320 uses the even-order temperature voltage characteristic in addition to the odd-order temperature-voltage characteristic to generate the second order. It is desirable to generate a control signal.

For example, the second control unit 320, the temperature detection result is T _x, when the comparison result of the encoder 340 is high voltage, the temperature of the first control unit 310 is excessively compensated to the curve C 'shown in FIG. 3 Compensates for characteristic components. The n-th order component generation unit 370 outputs a value corresponding to the temperature T _x in the temperature voltage characteristic that compensates for the temperature characteristic component that is excessively compensated by the first control unit 310. Here, if the temperature voltage characteristic that compensates the temperature characteristic of the curve C ′ is F _1n (T), the second controller 320 generates F _1n (T _x ).

In addition, when the comparison result of the encoder 340 is a low voltage, the second control unit 320 compensates for the temperature characteristic component that the first control unit 310 has insufficiently compensated for, as indicated by a curve C ″ shown in FIG. The next component generation unit 370 outputs values corresponding to the temperature T _x in the temperature voltage characteristics for compensating for the component of the compensation result that the first control unit 310 is insufficient. Here, the temperature characteristics of the curve C ″ are compensated. When the temperature voltage characteristic to be performed is F _2n (T), the second control unit 320 generates F _2n (T _x ).

The second adder 380 adds the temperature detection result of the vibrator 10 and the n-th order temperature voltage characteristic with the reference temperature as the origin, corresponding to the comparison result between the second control signal and the reference voltage. The second addition unit 380 supplies the addition result to the amplification unit 390. That is, the second adder 380 amplifies Σ _n {F _1n (T _x )} when the comparison result of the encoder 340 is a high voltage, and amplifies Σ _n {F _2n (T _x )} when the comparison result is a low voltage. Part 390.

The amplifying unit 390 amplifies the external input signal with an amplification factor according to the addition result of the second adding unit 380. The amplifying unit 390 outputs the amplified external input signal as a second control signal. That is, the second control unit 320 switches the amplification factor of the amplification unit 390 based on the temperature detection result of the vibrator 10 and the comparison result between the second control signal and the reference voltage. For example, when the comparison result of the encoder 340 is a high voltage, the amplification unit 390 uses the positive adjustment gain Σ _n {F _1n (T _x )}, and when the comparison result of the encoder 340 is a low voltage, the amplification unit 390 uses the negative adjustment gain. The external input signal is amplified using the gain Σ _n {F _2n (T _x )}. As described above, the amplification unit 390 switches the amplification factor according to the addition result of the second addition unit 380.

  Here, since the encoder 340 compares the second control signal output from the second control unit 320 with the reference voltage, an offset is generated in a circuit preceding the second control unit 320 to generate the second control signal. Even if they are superimposed, the second control signal on which the offset is superimposed is compared with the reference voltage. That is, the second control unit 320 selects either the positive adjustment gain or the negative adjustment gain based on the control signal including the generated offset.

For example, when the frequency shift amount is + Δf ₁ and the frequency shift amount corresponding to the offset error is + Δf ₄ , the external input signal is a signal corresponding to the frequency f ₀ + Δf ₁ −Δf ₄ . As a result, when the offset error is superimposed, the frequency shift amount of the control signal becomes + Δf _1, and the oscillation circuit 200 shifts the oscillation frequency of the vibrator 10 to the high frequency side (positive side). Further, since the encoder 340 compares the control signal with a reference voltage, even if the external input signal is a signal voltage corresponding to a frequency (f ₀ + Δf ₁ −Δf ₄ ) equal to or lower than the reference frequency f ₀ , the comparison result Since f ₀ + Δf ₁ > f ₀ , a high voltage is output. That is, the amplifying unit 390 amplifies the external input signal using the positive side adjustment gain.

  As described above, the oscillation device 2000 according to the present embodiment associates the gain of the amplification unit 390 with the direction in which the oscillation circuit 200 changes the oscillation frequency regardless of the value of the external input signal. The temperature characteristic can be compensated appropriately. Further, since the oscillation device 2000 adjusts the oscillation frequency of the vibrator 10 according to the external input signal that reduces the offset error, the vibrator 10 can be oscillated at the oscillation frequency corresponding to the shift amount of the external input signal. it can.

  Moreover, the encoder 340 of this embodiment shows an example having a hysteresis comparator. The encoder 340 includes a comparator 342, an input resistor 344, a feedback resistor 346, and an inverter 348. The comparator 342, the input resistor 344, and the feedback resistor 346 operate as a hysteresis comparator having hysteresis as a threshold value.

For example, if the hysteresis comparator has a first threshold Th _H and a second threshold Th _L , and Th _H > Th _L , the output is low when the difference between the input voltage and the reference voltage exceeds the first threshold Th _H. Voltage. In this case, even if the difference between the input voltage and the reference voltage becomes equal to or less than the first threshold Th _H , the output maintains a low voltage, and after the difference becomes equal to or less than the second threshold Th _L , the output switches to the high voltage. In this case, the output maintains the high voltage even when the difference between the input voltage and the reference voltage exceeds the second threshold Th _L , and the output switches to the low voltage after exceeding the first threshold Th _H.

The first threshold Th _H and the second threshold Th _L can be determined by the input resistance 344, the feedback resistance 346, the reference voltage, the power supply voltage of the comparator 342, and the like. Further, the difference (hysteresis) of the threshold voltage with respect to the output full scale can be determined by the ratio of the input resistor 344 and the feedback resistor 346. The inverter 348 inverts the logic of such a hysteresis comparator.

In the above encoder 340, even if the external input signal fluctuates including noise or the like when the external input signal is substantially the same value as the reference voltage, the fluctuation is the difference between the first threshold Th _H and the second threshold Th _L. If it is within the range, a stable logical value can be output without reflecting noise fluctuations. Thus, since the encoder 340 prevents chattering from occurring even when the external input signal fluctuates, the oscillation device 2000 can prevent chattering from occurring at the oscillation frequency.

  FIG. 11 shows an example of the oscillation frequency output from the oscillation device 2000 according to the present embodiment. In FIG. 11, the horizontal axis represents time, and the vertical axis represents the oscillation frequency corresponding to the external input signal. FIG. 11 shows an example in which the external input signal changes over time and the oscillation device 2000 outputs an oscillation frequency corresponding to the changed external input signal. As described with reference to FIGS. 9 and 10, the oscillation device 2000 can oscillate the vibrator 10 at an oscillation frequency corresponding to an external input signal while compensating for the temperature characteristics of the vibrator 10.

Even if the external input signal has substantially the same value as the reference voltage, the oscillation device 2000 can operate stably without changing the oscillation frequency. For example, the oscillation device 2000 can prevent chattering of the oscillation frequency during the period from time t ₃ to t ₄ and also during the period from time t ₅ to t ₆ . As described above, the oscillation device 2000 according to the present embodiment can oscillate the vibrator 10 while stabilizing the output frequency while compensating for the temperature characteristics regardless of the magnitude of the external input signal.

  In the oscillation device 2000 according to the present embodiment described above, the first control unit 310 and the second control unit 320 each have an n-order component generation unit, but the present invention is not limited to this. The first controller 310 and / or the second controller 320 may include at least a third-order component generator, and may generate at least a third-order temperature voltage characteristic.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

10 vibrator, 20 temperature detection unit, 32 input terminal, 34 output terminal, 36 reference voltage input terminal, 100 oscillation control device, 110 first capacitance control unit, 120 second capacitance control unit, 130 comparison unit, 140 third capacitance Control unit, 200 oscillation circuit, 210 first variable capacitance unit, 220 second variable capacitance unit, 230 third variable capacitance unit, 240 fourth variable capacitance unit, 250 resistor, 260 amplification unit, 300 oscillation control device, 310 first Control unit, 320 second control unit, 330 reference voltage generation unit, 340 encoder, 342 comparator, 344 input resistance, 346 feedback resistance, 348 inverter, 350 n-order component generation unit, 351 primary component generation unit, 352 secondary component Generation unit, 353 Third-order component generation unit, 360 First addition unit, 370 n-order component generation unit, 371 Primary-component generation unit 372 secondary component generating portion, 373 cubic component generating unit, 380 second adding unit, 390 amplifier unit, 1000 oscillator 2000 oscillating device

Claims (11)

A first control unit that generates a first control signal for controlling the oscillation frequency of the vibrator based on the temperature detection result of the temperature detection unit;
An encoder that generates a feedback signal;
A second control unit that generates a second control signal for controlling an oscillation frequency of the vibrator based on the temperature detection result of the temperature detection unit, an external input signal input from the outside, and the feedback signal;
An oscillation circuit for setting an oscillation frequency of the vibrator based on the first control signal and the second control signal;
A reference voltage generator for generating a reference voltage;
With
The encoder generates the feedback signal by comparing the second control signal and the reference voltage ;
The second controller is
An amplification unit for amplifying the external input signal;
Based on the temperature detection result and the comparison result of the second control signal and the reference voltage, the amplification factor of the amplification unit is switched.
Oscillation control device. The encoder outputs digital data indicating a difference between the reference voltage and the second control signal;
The oscillation control apparatus according to claim 1, wherein the second control unit receives the digital data as the feedback signal. The encoder converts the difference between the reference voltage and the second control signal and a comparison result with a threshold value into the digital data,
The oscillation control apparatus according to claim 2, wherein the threshold level has hysteresis.   The oscillation control device according to claim 3, wherein the encoder includes a hysteresis comparator. The oscillation circuit is
A first variable capacitance unit that changes a capacitance value based on the first control signal;
A second variable capacitance unit that changes a capacitance value based on the second control signal;
Have
5. The oscillation control device according to claim 1, wherein an oscillation frequency of the vibrator is set based on capacitances of the first variable capacitance unit and the second variable capacitance unit. 6. The oscillation control device according to claim 1, wherein the amplification unit outputs the amplified external input signal as the second control signal. 7. The second control unit adds the nth-order temperature voltage characteristic with a reference temperature as an origin corresponding to the temperature detection result and the comparison result of the second control signal and the reference voltage. An adder,
In response to said second adding section of the addition result, switches the amplification factor of the amplifying unit, the oscillation control device according to any one of claims 1 to 6. The first controller is
In accordance with the temperature detection result, a first addition unit that adds an nth-order temperature voltage characteristic with the reference temperature as an origin,
The oscillation control device according to claim 7 , wherein an addition result of the first addition unit is the first control signal. The oscillation control device according to claim 7 or 8 , wherein the order n of the temperature voltage is a natural number of 1 or more. The vibrator;
A temperature detector for detecting the temperature of the vibrator;
An input terminal to which the external input signal from the outside is input;
The oscillation control device according to any one of claims 1 to 9 ,
An oscillation device comprising: The oscillation device according to claim 10 , wherein the vibrator is a crystal vibrator.

Images