Oscillator, electronic device, and moving object

Patent metadata

Field	Value
Publication number	US-10284206-B2
Application number	US-201615378358-A
Country	US
Kind code	B2
Filing date	Dec 14, 2016
Priority date	Dec 21, 2015
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

An oscillator includes: an oscillation stage circuit that is connected between a first electrode and a second electrode of a resonator and performs an oscillation operation; a variable capacitance element that is connected to the first or second electrode of the resonator and adjusts an oscillation frequency; a bandgap reference circuit that generates a reference voltage having magnitude, which changes depending on the temperature, by using a resistor inserted in a current path through which a current having magnitude, which changes depending on the temperature flows; and a bias current generating circuit that generates a bias current of the oscillation stage circuit based on the reference voltage, and that, thereby, reduces a change in the oscillation frequency due to the temperature dependence of the impedance of the resonator or the temperature dependence of the sensitivity of the variable capacitance element.

First claim

What is claimed is:

1. An oscillator comprising:
an oscillation stage circuit that is connected between a first electrode and a second electrode of a resonator and performs an oscillation operation;
a variable capacitance element that is connected to the first or second electrode of the resonator and adjusts an oscillation frequency;
a bandgap reference circuit that generates a reference voltage having magnitude that changes depending on temperature, the bandgap reference circuit having:
a first current path to which a first resistor, a second resistor, and a first transistor or a first diode are connected in series; and
a second current path to which a third resistor, a plurality of second transistors or a plurality of second diodes which are connected in parallel, respectively, and a fourth resistor are connected in series, the first or second current path having a current with a magnitude that changes depending on temperature, the reference voltage being generated at a connection point between the first resistor and the second resistor; and

a bias current generating circuit that generates a bias current of the oscillation stage circuit based on the reference voltage, and thereby reduces a change in the oscillation frequency due to temperature dependence of impedance of the resonator or temperature dependence of sensitivity of the variable capacitance element.

2. The oscillator according to claim 1 , wherein the bias current generating circuit includes a current adjusting resistor that has a temperature coefficient different from a temperature coefficient of one of the first, second, third, and fourth resistors, and generates the current based on the reference voltage and a resistance value of the current adjusting resistor.

3. The oscillator according to claim 2 , wherein the current adjusting resistor has the temperature coefficient higher than the temperature coefficient of the one resistor.

4. The oscillator according to claim 1 , wherein the bias current has temperature dependence lower than temperature dependence of the current flowing through the first or second current path.

5. An oscillator comprising:
an oscillation stage circuit that is connected between a first electrode and a second electrode of a resonator and performs an oscillation operation;
a variable capacitance element that is connected to the first or second electrode of the resonator and adjusts an oscillation frequency;
a bandgap reference circuit that generates a reference voltage, the bandgap reference circuit having:
a first current path to which a first resistor, a second resistor, and a first transistor or a first diode are connected in series; and
a second current path to which a third resistor, a plurality of second transistors or a plurality of second diodes which are connected in parallel, respectively, and a fourth resistor are connected in series, the reference voltage being generated at a connection point between the first resistor and the second resistor; and

a bias current generating circuit that includes a current adjusting resistor having a temperature coefficient different from a temperature coefficient of one of the first, second, third, and fourth resistors, the bias current generating circuit generating a bias current of the oscillation stage circuit based on the reference voltage and a resistance value of the current adjusting resistor, and thereby reducing a change in the oscillation frequency due to temperature dependence of impedance of the resonator or temperature dependence of sensitivity of the variable capacitance element.

6. The oscillator according to claim 5 , wherein the current adjusting resistor has the temperature coefficient higher than the temperature coefficient of the one resistor.

7. The oscillator according to claim 5 , wherein the bias current has temperature dependence lower than temperature dependence of a current flowing through one of the first current path and the second current path.

8. An oscillator comprising:
an oscillation stage circuit that is connected between a first electrode and a second electrode of a resonator and performs an oscillation operation;
a variable capacitance element that is connected to the first or second electrode of the resonator and adjusts an oscillation frequency;
a bandgap reference circuit that generates a reference voltage, the bandgap reference circuit having:
a first current path to which a first resistor, a second resistor, and a first transistor or a first diode are connected in series; and
a second current path to which a third resistor, a plurality of second transistors or a plurality of second diodes which are connected in parallel, respectively, and a fourth resistor are connected in series, the reference voltage being generated at a connection point between the first resistor and the second resistor;

a bias current generating circuit that generates a bias current of the oscillation stage circuit based on the reference voltage and a resistance value of a current adjusting resistor; and
a setting circuit that sets a value of one of the first, second, third, and fourth resistors in response to data stored in a storage unit, or that generates a selection signal for selecting the current adjusting resistor from a plurality of resistors.

9. An electronic device comprising:
the oscillator according to claim 1 .

10. A moving object comprising:
the oscillator according to claim 1 .

Assignees

• Seiko Epson Corp

Inventors

• Itasaka Yosuke

Classifications

• H03L1/02 Primary

  against variations of temperature only · CPC title

• H03B2200/0038

  including a current mirror · CPC title

• H03B5/368

  the means being voltage variable capacitance diodes · CPC title

• H03B5/362 Primary

  the amplifier being a single transistor (H03B5/364 - H03B5/368 take precedence) · CPC title

• H03H9/19

  consisting of quartz · CPC title