VOLTAGE CONTROL TYPE TEMPERATURE COMPENSATION PIEZOELECTRIC OSCILLATOR

• US 20100127787A1
• Filed: 11/16/2009
• Published: 05/27/2010
• Est. Priority Date: 11/26/2008
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Epson Toyocom Corporation (Seiko Group)
• Inventors: YAMAMOTO, Takehiro, ISHIKAWA, Masayuki, KIYOHARA, Atsushi, KUROGO, Shigehisa, MATSUKAWA, Norihito
• Granted Patent: US 8,058,941 B2
• Time in Patent Office: Days
• US Class Current: 331/158
• CPC Class Codes: H03B 5/04 Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature

Abstract

A voltage control type temperature compensation piezoelectric oscillator, includes: a voltage control type oscillation circuit; an automatic frequency control (AFC) circuit outputting a control voltage for controlling an oscillation frequency of the voltage control type oscillation circuit based on an external control voltage; a temperature compensation voltage generating circuit generating a temperature compensation voltage; and a gain variable circuit varying a gain of the temperature compensation voltage. In the oscillator, the gain variable circuit is controlled by the control voltage outputted from the AFC circuit, and the oscillation frequency of the voltage control type oscillation circuit is controlled by an output voltage of the gain variable circuit.

Claims

1. A voltage control type temperature compensation piezoelectric oscillator, comprising:

a voltage control type oscillation circuit;

an automatic frequency control (AFC) circuit outputting a control voltage for controlling an oscillation frequency of the voltage control type oscillation circuit based on an external control voltage;

a temperature compensation voltage generating circuit generating a temperature compensation voltage; and

a gain variable circuit varying a gain of the temperature compensation voltage, wherein

the gain variable circuit is controlled by the control voltage outputted from the AFC circuit, and the oscillation frequency of the voltage control type oscillation circuit is controlled by an output voltage of the gain variable circuit.

2. The voltage control type temperature compensation piezoelectric oscillator according to claim 1, wherein the temperature compensation voltage generating circuit includes:

a temperature sensor;

a primary voltage generating circuit;

a high-order voltage generating circuit for a third-order voltage or a higher-order voltage; and

an adder circuit adding a primary voltage generated by the primary voltage generating circuit and a high-order voltage generated by the high-order voltage generating circuit.

3. The voltage control type temperature compensation piezoelectric oscillator according to claim 1, wherein the voltage control type oscillation circuit includes:

a piezoelectric resonator;

a first variable capacitance element for temperature compensation; and

a second variable capacitance element for varying a center frequency, the first variable capacitance element and the second variable capacitance element being coupled to the piezoelectric resonator.

4. The voltage control type temperature compensation piezoelectric oscillator according to claim 3, wherein the first variable capacitance element and the second variable capacitance element are respectively coupled to both terminals of the piezoelectric resonator.

5. The voltage control type temperature compensation piezoelectric oscillator according to claim 1, wherein the gain variable circuit includes an operational amplifier, a first resistor, a second resistor, a transistor, and a reference voltage, and the second resistor and the transistor are coupled in parallel and are coupled to an input terminal and an output terminal of the operational amplifier.

6. The voltage control type temperature compensation piezoelectric oscillator according to claim 1, wherein the gain variable circuit includes an operational amplifier, a first resistor, a second resistor, a transistor, and a reference voltage, and the first resistor and the transistor are coupled in parallel and are coupled to an input terminal of the operational amplifier.