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JP-7855848-B2 - Circuit devices and oscillators

JP7855848B2JP 7855848 B2JP7855848 B2JP 7855848B2JP-7855848-B2

Inventors

  • 板坂 洋佑

Assignees

  • セイコーエプソン株式会社

Dates

Publication Date
20260511
Application Date
20211116

Claims (8)

  1. A circuit device used in an oscillator having a resonator, An oscillator circuit comprising: a first variable capacitance circuit electrically connected to the oscillator and having a positive capacitance change characteristic with respect to a first capacitance control voltage; and a second variable capacitance circuit electrically connected to the oscillator and having a negative capacitance change characteristic with respect to a second capacitance control voltage, wherein the oscillator is made to oscillate, and the oscillation frequency is controlled by variably adjusting the load capacitance by the first and second variable capacitance circuits , A switch circuit that receives a first input voltage at a first input terminal, a second input voltage at a second input terminal, outputs a first output voltage selected from a plurality of voltages including the first input voltage and the second input voltage as the first capacitance control voltage of the first variable capacitor circuit to a first output terminal to which the first variable capacitor circuit is electrically connected, and outputs a second output voltage selected from the plurality of voltages as the second capacitance control voltage of the second variable capacitor circuit to a second output terminal to which the second variable capacitor circuit is electrically connected, A temperature sensor and A temperature compensation circuit outputs a temperature compensation voltage that compensates for the oscillation frequency based on the temperature detection result of the temperature sensor, A frequency control circuit that outputs a frequency control voltage of the oscillation frequency, Includes, The voltage selection of the switch circuit is set by information stored in non-volatile memory, fuse settings by the fuse circuit, or switching of the mask layer, thereby setting the normal operating mode of the oscillator from among multiple operating modes. The aforementioned switch circuit is When the oscillator's normal operating mode is set to the VC-TCXO operating mode, the oscillator is operated as a VC-TCXO by outputting the temperature compensation voltage based on the temperature detection result of the temperature sensor as the first capacitance control voltage of the first variable capacitance circuit to the first output terminal , and the frequency control voltage as the second capacitance control voltage of the second variable capacitance circuit to the second output terminal , thereby performing temperature compensation by the temperature compensation voltage and frequency control by the frequency control voltage. A circuit device characterized in that, when the oscillator's normal operating mode is set to the SPXO operating mode , a third fixed voltage is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit , and a fourth fixed voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit , thereby operating the oscillator as an SPXO without temperature compensation by the temperature compensation voltage or frequency control by the frequency control voltage.
  2. In the circuit device according to claim 1, The aforementioned switch circuit is When the oscillator's normal operating mode is set to the TCXO operating mode , the temperature compensation voltage based on the temperature detection result of the temperature sensor is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit , and the first fixed voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit , thereby operating the oscillator as a TCXO in which frequency control by the frequency control voltage is not performed, but temperature compensation by the temperature compensation voltage is performed. A circuit device characterized in that, when the normal operating mode of the oscillator is set to the VCXO operating mode , a second fixed voltage is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit , and the frequency control voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit , thereby operating the oscillator as a VCXO in which temperature compensation is not performed by the temperature compensation voltage but frequency control is performed by the frequency control voltage.
  3. In the circuit device according to claim 2, The aforementioned switch circuit is A circuit device characterized by outputting a fixed voltage on the high-potential side or a fixed voltage on the low-potential side as the first fixed voltage and the second fixed voltage.
  4. In the circuit device according to any one of claims 1 to 3, The first variable capacitance circuit is, The temperature compensation voltage is supplied to the gate, and the circuit includes multiple transistors to which multiple reference voltages generated by a reference voltage generation circuit are supplied to the source and drain. The second variable capacitance circuit is, A circuit device characterized by including a plurality of transistors to which the frequency control voltage is supplied to the source and drain, and to which a plurality of different reference voltages generated by the reference voltage generation circuit are supplied to the gate.
  5. The oscillator and, Circuit equipment and, Includes, The aforementioned circuit device is An oscillator circuit comprising: a first variable capacitance circuit electrically connected to the oscillator and having a positive capacitance change characteristic with respect to a first capacitance control voltage; and a second variable capacitance circuit electrically connected to the oscillator and having a negative capacitance change characteristic with respect to a second capacitance control voltage, wherein the oscillator is made to oscillate, and the oscillation frequency is controlled by variably adjusting the load capacitance by the first and second variable capacitance circuits , A switch circuit that receives a first input voltage at a first input terminal, a second input voltage at a second input terminal, outputs a first output voltage selected from a plurality of voltages including the first input voltage and the second input voltage as the first capacitance control voltage of the first variable capacitor circuit to a first output terminal to which the first variable capacitor circuit is electrically connected, and outputs a second output voltage selected from the plurality of voltages as the second capacitance control voltage of the second variable capacitor circuit to a second output terminal to which the second variable capacitor circuit is electrically connected, A temperature sensor and A temperature compensation circuit outputs a temperature compensation voltage that compensates for the oscillation frequency based on the temperature detection result of the temperature sensor, A frequency control circuit that outputs a frequency control voltage of the oscillation frequency, Includes, The voltage selection of the switch circuit is set by information stored in non-volatile memory, fuse settings by the fuse circuit, or switching of the mask layer, thereby setting the normal operating mode of the oscillator from among multiple operating modes. The aforementioned switch circuit is When the oscillator's normal operating mode is set to the VC-TCXO operating mode, the oscillator is operated as a VC-TCXO by outputting the temperature compensation voltage based on the temperature detection result of the temperature sensor as the first capacitance control voltage of the first variable capacitance circuit to the first output terminal , and the frequency control voltage as the second capacitance control voltage of the second variable capacitance circuit to the second output terminal , thereby performing temperature compensation by the temperature compensation voltage and frequency control by the frequency control voltage. An oscillator characterized in that, when the oscillator's normal operating mode is set to the SPXO operating mode , a third fixed voltage is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit , and a fourth fixed voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit , thereby operating the oscillator as an SPXO in which neither temperature compensation by the temperature compensation voltage nor frequency control by the frequency control voltage is performed.
  6. In the oscillator according to claim 5, The aforementioned switch circuit is When the oscillator's normal operating mode is set to the TCXO operating mode , the temperature compensation voltage based on the temperature detection result of the temperature sensor is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit , and the first fixed voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit , thereby operating the oscillator as a TCXO in which frequency control by the frequency control voltage is not performed, but temperature compensation by the temperature compensation voltage is performed. An oscillator characterized in that, when the normal operating mode of the oscillator is set to the VCXO operating mode , a second fixed voltage is output to the first output terminal as the first capacitance control voltage of the first variable capacitance circuit , and the frequency control voltage is output to the second output terminal as the second capacitance control voltage of the second variable capacitance circuit, thereby operating the oscillator as a VCXO in which temperature compensation is not performed by the temperature compensation voltage but frequency control is performed by the frequency control voltage.
  7. In the oscillator according to claim 6, The aforementioned switch circuit is An oscillator characterized by outputting a fixed voltage on the high-potential side or a fixed voltage on the low-potential side as the first fixed voltage and the second fixed voltage.
  8. In the oscillator according to any one of claims 5 to 7, The first variable capacitance circuit is, The temperature compensation voltage is supplied to the gate, and the circuit includes multiple transistors to which multiple reference voltages generated by a reference voltage generation circuit are supplied to the source and drain. The second variable capacitance circuit is, An oscillator characterized by including a plurality of transistors to which the frequency control voltage is supplied to the source and drain, and to which a plurality of different reference voltages generated by the reference voltage generation circuit are supplied to the gate.

Description

This invention relates to circuit devices and oscillators, etc. In circuit devices that generate oscillations using oscillators such as quartz crystals, a variable capacitance circuit is provided to adjust the oscillation frequency. For example, in the oscillation circuit described in Patent Document 1, an inverting amplifier is provided between a voltage-controlled oscillator, which changes the oscillation frequency according to a control voltage, and an amplifier that outputs the control voltage, to reverse the polarity of the control voltage. Japanese Patent Application Publication No. 07-226679 An example of the configuration of the circuit device and oscillator according to this embodiment.Detailed configuration example of the circuit device and oscillator of this embodiment.Diagram illustrating the voltage-capacitance characteristics of the positive characteristics of the first variable capacitance circuit.Diagram illustrating the negative voltage capacitance characteristics of the second variable capacitance circuit.An example of a switch circuit configuration.A diagram illustrating the setting of the operating mode using a switch circuit.Other examples of switch circuit configurations.Detailed other configuration examples of the circuit device and oscillator of this embodiment.A first example of an oscillator circuit configuration.A second example of the oscillator circuit configuration.Diagram illustrating the first variable capacitance circuit.Diagram illustrating the voltage-capacitance characteristics of the first variable capacitance circuit.Diagram illustrating the voltage-capacitance characteristics of the first variable capacitance circuit.Diagram illustrating the second variable capacitance circuit.Diagram illustrating the voltage-capacitance characteristics of the second variable capacitance circuit.Diagram illustrating the voltage-capacitance characteristics of the second variable capacitance circuit.An example of the frequency-temperature characteristics of an oscillator.An example of the temperature characteristics of the temperature compensation voltage when using a second variable capacitance circuit with negative characteristics.An example of the temperature characteristics of the temperature compensation voltage when using a first variable capacitance circuit with positive characteristics.An example of a temperature compensation circuit configuration.An example configuration of a Class A amplifier circuit.An example configuration of a Class AB amplifier circuit.An example of a frequency control circuit configuration.A first structural example of an oscillator.A second example of the oscillator structure. The following describes this embodiment. Note that the embodiment described below does not unduly limit the scope of the claims. Furthermore, not all of the configurations described in this embodiment are necessarily essential components. 1. Circuit Device Figure 1 shows an example of the configuration of the circuit device 20 of this embodiment. The circuit device 20 of this embodiment includes an oscillation circuit 30 and a switch circuit 36. The oscillator 4 of this embodiment also includes a vibrator 10 and the circuit device 20. The vibrator 10 is electrically connected to the circuit device 20. The oscillator 10 is an element that generates mechanical vibrations in response to an electrical signal. The oscillator 10 can be realized by a vibrating element, such as a quartz crystal vibrator. For example, the oscillator 10 can be realized by a quartz crystal vibrator that vibrates with thickness shear, such as an AT cut or SC cut, a tuning fork type quartz crystal vibrator, or a double tuning fork type quartz crystal vibrator. For example, the oscillator 10 may be an oscillator built into a temperature-compensated crystal oscillator (TCXO) without a constant temperature chamber, or an oscillator built into a constant temperature chamber type quartz oscillator (OCXO) with a constant temperature chamber. Alternatively, the oscillator 10 may be an oscillator built into an SPXO (Simple Packaged Crystal Oscillator). In this embodiment, the oscillator 10 can also be realized by various vibrating elements, such as vibrating elements other than thickness shear type, tuning fork type, or double tuning fork type, or piezoelectric vibrating elements made of materials other than quartz. For example, the oscillator 10 can be a SAW (Surface Acoustic Wave) resonator or a MEMS (Micro Electro Mechanical Systems) oscillator, which is a silicon oscillator formed using a silicon substrate. The circuit device 20 is an integrated circuit (IC). For example, the circuit device 20 is an IC manufactured using a semiconductor process, and is a semiconductor chip with circuit elements formed on a semiconductor substrate. In Figure 1, the circuit device 20 includes an oscillator circuit 30 and a switch circuit 366, and the oscillator circuit 30 includes a first variable capacitance circuit 31 and a second v