Oscillation control apparatus and oscillation apparatus
Provided is an oscillation apparatus and an oscillation control apparatus including a first control section that generates a first control signal that controls an oscillation frequency of an oscillator, based on a temperature detection result of a temperature detecting section; an encoder that generates a feedback signal; a second control section that generates a second control signal that controls the oscillation frequency of the oscillator, based on the temperature detection result of the temperature detecting section, an external input signal input from outside, and the feedback signal; an oscillation circuit that sets the oscillation frequency of the oscillator, based on the first control signal and the second control signal; and a reference voltage generating section that generates a reference voltage, wherein the encoder generates the feedback signal by comparing the second control signal and the reference voltage.
1. An oscillation control apparatus comprising:
a first control section that generates a first control signal that controls an oscillation frequency of an oscillator, based on a temperature detection result of a temperature detecting section;
an encoder that generates a feedback signal;
a second control section that generates a second control signal that controls the oscillation frequency of the oscillator, based on the temperature detection result of the temperature detecting section, an external input signal input from outside, and the feedback signal;
an oscillation circuit that sets the oscillation frequency of the oscillator, based on the first control signal and the second control signal; and
a reference voltage generating section that generates a reference voltage, wherein
the encoder generates the feedback signal by comparing the second control signal and the reference voltage.
2. The oscillation control apparatus according to claim 1 , wherein
the encoder outputs digital data indicating a difference between the reference voltage and the second control signal, and
the second control section has the digital data input thereto as the feedback signal.
3. The oscillation control apparatus according to claim 2 , wherein
the encoder converts the difference between the reference voltage and the second control signal into the digital data based on a comparison result of the difference and a threshold value, and
a level of the threshold value includes a hysteresis.
4. The oscillation control apparatus according to claim 3 , wherein
the encoder includes a hysteresis comparator.
5. The oscillation control apparatus according to claim 1 , wherein the oscillation circuit:
includes a first variable capacitance section that changes a capacitance value thereof based on the first control signal,
includes a second variable capacitance section that changes a capacitance value thereof based on the second control signal, and
sets the oscillation frequency of the oscillator based on the capacitances of the first variable capacitance section and the second variable capacitance section.
6. The oscillation control apparatus according to claim 1 , wherein the second control section:
includes an amplifying section that amplifies the external input signal, and
switches an amplification rate of the amplifying section based on the temperature detection result and a comparison result of the second control signal and the reference voltage.
7. The oscillation control apparatus according to claim 6 , wherein
the amplifying section outputs the external input signal that has been amplified, as the second control signal.
8. The oscillation control apparatus according to claim 6 , wherein
the second control section includes a second adding section that adds together n orders of a 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, and
the amplification rate of the amplifying section is switched according to an addition result of the second adding section.
9. The oscillation control apparatus according to claim 8 , wherein the first control section:
includes a first adding section that adds together n orders of the temperature voltage characteristic with the reference temperature as the origin, according to the temperature detection result, and
sets an addition result of the first adding section as the first control signal.
10. The oscillation control apparatus according to claim 8 , wherein
the number of orders n of the temperature voltage characteristic is a natural number greater than or equal to 1.
11. An oscillation apparatus comprising:
an oscillator;
a temperature detecting section that detects a temperature of the oscillator;
an input terminal that inputs an external input signal from outside; and
the oscillation control apparatus according to claim 1 .
12. The oscillation apparatus according to claim 11 , wherein
the oscillator is a crystal oscillator.