Oscillation circuit, circuit device, oscillator, electronic apparatus, and vehicle

Patent metadata

Field	Value
Publication number	US-10469089-B2
Application number	US-201715814951-A
Country	US
Kind code	B2
Filing date	Nov 16, 2017
Priority date	Nov 18, 2016
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

An oscillation circuit includes an amplification circuit that causes a resonator to oscillate, and a variable capacitance circuit whose capacitance value is controlled on the basis of a control voltage. The variable capacitance circuit includes a first variable capacitive element in which an inflection point voltage in a change characteristic of a capacitance value for the control voltage is a first voltage, and a second variable capacitive element in which an inflection point voltage in a change characteristic of a capacitance value for the control voltage is a second voltage which is different from the first voltage. A capacitance value of the first variable capacitive element when the control voltage is the first voltage is different from a capacitance value of the second variable capacitive element when the control voltage is the second voltage.

First claim

What is claimed is:

1. An oscillation circuit comprising:
an amplification circuit configured to cause a resonator to oscillate; and
a variable capacitance circuit whose capacitance value is controlled based on a control voltage,
wherein the variable capacitance circuit includes:
a first variable capacitive element in which an inflection point voltage in a change characteristic of a capacitance value for the control voltage is a first voltage; and
a second variable capacitive element in which an inflection point voltage in a change characteristic of a capacitance value for the control voltage is a second voltage which is different from the first voltage,

wherein the capacitance value of the first variable capacitive element when the control voltage is the first voltage is different from the capacitance value of the second variable capacitive element when the control voltage is the second voltage, and
wherein the first variable capacitive element is configured with a first transistor having a first threshold voltage, and the second variable capacitive element is configured with a second transistor having a second threshold voltage which is different from the first threshold voltage.

2. The oscillation circuit according to claim 1 ,
wherein the first variable capacitive element is configured with n unit transistors including the first transistor, and the second variable capacitive element is configured with m unit transistors including the second transistor, and
the n is an integer of two or more, and the m is an integer of two or more and is different from the n.

3. A circuit device comprising:
the oscillation circuit according to claim 2 ;
a temperature sensor configured to detect a temperature; and
a controller configured to generate the control voltage corresponding to the detected temperature.

4. An oscillator comprising:
the oscillation circuit according to claim 2 ;
the resonator; and
a package housing the oscillation circuit and the resonator.

5. An electronic apparatus comprising:
the oscillation circuit according to claim 2 ; and
a communication device configured to receive a signal from the oscillation circuit so as to receive and transmit date from and to an external device.

6. The oscillation circuit according to claim 1 ,
wherein the first transistor of the first variable capacitive element has a first transistor size, and the second transistor of the second variable capacitive element has a second transistor size which is different from the first transistor size.

7. The oscillation circuit according to claim 2 ,
wherein, in each of the first variable capacitive element and the second variable capacitive element, the control voltage is supplied to one of a first node and a second node, and a reference voltage is supplied to the other of the first node and the second node, and
the first rode is a gate node, and the second node is a node of a source and a drain.

8. The oscillation circuit according to claim 1 ,
wherein the first variable capacitive element has first and second ends, the control voltage is supplied to the first end, and a first reference voltage is supplied to the second end,
wherein the second variable capacitive element has third and fourth ends, the control voltage is supplied to the third end, and a second reference voltage is supplied to the fourth end, and
the second a reference voltage is different from the first reference voltage.

9. The oscillation circuit according to claim 1 ,
wherein the first variable capacitive element has a first potential difference-capacitance value characteristic which is a change characteristic of a capacitance value for a potential difference between one end and the other end thereof,
wherein the second variable capacitive element has a second potential difference-capacitance value characteristic which is a change characteristic of a capacitance value for a potential difference between one end and the other end thereof, and
the second potential difference-capacitance value characteristic is different from the first potential difference-capacitance value characteristic.

10. The oscillation circuit according to claim 1 ,
wherein the variable capacitance circuit further includes a third variable capacitive element in which a change in a capacitance value occurs at an inflection point when the control voltage is a third voltage which is different from the first voltage and the second voltage.

11. The oscillation circuit according to claim 10 ,
wherein the first variable capacitive element is provided at an input node of the amplification circuit, the second variable capacitive element is provided at an output node of the amplification circuit, and the third variable capacitive element is provided at one of the input node and the output node of the amplification circuit.

12. The oscillation circuit according to claim 10 ,
wherein each of the first variable capacitive element and the second variable capacitive element has a first potential difference-capacitance value characteristic which is a change characteristic of a capacitance value for a potential difference between one end and the other end thereof,
the capacitance value of the first variable capacitive element is controlled based on a difference between a first reference voltage and the control voltage,
the capacitance value of the second variable capacitive element is controlled based on a difference between the control voltage and a second reference voltage which is different from the first reference voltage, and
wherein the third variable capacitive element has a second potential difference-capacitance value characteristic which is a chance characteristic of a capacitance value for a potential difference between one end and the other end thereof, and
the second potential difference-capacitance value characteristic is different from the first potential difference-capacitance value characteristic.

13. The oscillation circuit according to claim 10 ,
wherein the variable capacitance circuit further includes a fourth variable capacitive element in which a change in a capacitance value occurs at an inflection point when the control voltage is a fourth voltage which is different from the first voltage, the second voltage, and the third voltage.

14. A circuit device comprising:
the oscillation circuit according to claim 1 ;
a temperature sensor configured to detect a temperature; and
a controller configured to generate the control voltage corresponding to the detected temperature.

15. An oscillator comprising:
the oscillation circuit according to claim 1 ;
the resonator; and
a package housing the oscillation circuit and the resonator.

16. An electronic apparatus comprising:
the oscillation circuit according to claim 1 ; and
a communication device configured to receive a signal from the oscillation circuit so as to receive and transmit date from and to an external device.

17. A vehicle comprising
the oscillation circuit according to claim 1 ; and
a controller configured to operate based on a clock signal from the oscillation circuit.

18. An oscillation circuit comprising:
an amplification circuit configured to cause a resonator to oscillate; and
a variable capacitance circuit,
wherein the variable capacitance circuit includes:
a first variable capacitive element that has a first potential difference-capacitance value characteristic and is provided at an input node of the amplification circuit and whose capacitance value is controlled based on a difference between a co

Assignees

• Seiko Epson Corp

Inventors

• Yamamoto Takehiro
• Ishikawa Masayuki

Classifications

• H03H9/0547

  consisting of a vertical arrangement (H03H9/0566 takes precedence) · CPC title

• H03B5/368

  the means being voltage variable capacitance diodes · CPC title

• H03B5/04

  Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature · CPC title

• H03L1/04

  Constructional details for maintaining temperature constant · CPC title

• H03L1/025 Primary

  and a memory for digitally storing correction values · CPC title