Oscillation device

Abstract

To provide an oscillation device that captures a transient state and achieves a temperature post-compensation without measuring a power consumption.SOLUTION: An oscillation device 1 of the present invention is disposed in an environment having an ambient temperature, and includes a heater 10, an oscillator 11, and a temperature control circuit 12. The oscillator 11 is configured to generate a first clock signal whose a frequency is dependent on the ambient temperature. The temperature control circuit 12 is electrically connected directly to the heater 10. The temperature control circuit 12 detects the ambient temperature, generates an input voltage that is dependent on the ambient temperature, and provides the input voltage to the heater. The temperature control circuit 12 includes a MOSFET 120 and a temperature detection circuit 121. A drain of the MOSFET 120 is electrically connected directly to the heater 10. The MOSFET 120 and the heater 10 are electrically connected between a high voltage terminal and a low voltage terminal. The temperature detection circuit 121 is electrically connected to a gate of the MOSFET 120.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to electronic devices, and more particularly to oscillator devices. [Background technology]

[0002] Oscillator circuits play a central and increasingly important role in digital and analog electronic systems. Digital devices require precise system timing, a function provided by oscillators and similar timing sources. Telecommunications and data transmission systems with analog and digital components similarly rely on oscillators for modulation, demodulation, system clocking, and other functions.

[0003] The standard choice for a highly stable frequency source in such applications is a quartz-crystal-based oscillator or resonator. Atomic frequency standards offer high accuracy, but their use is limited due to cost and environmental compatibility issues. While quartz oscillators are more stable than non-quartz-based circuits, they still exhibit some variation in frequency and stability due to the inherent frequency response of the crystal to temperature changes and other environmental influences. One approach to correcting for the temperature effects of quartz crystals is to maintain a constant temperature in the oscillator's temperature-sensitive section. Devices such as oven-controlled crystal oscillators (OCXOs) offer better stability and frequency control. However, OCXOs require more careful manufacturing to achieve stability comparable to atomic frequency standards, resulting in higher costs. In U.S. Patent No. 6,784,756, an OCXO monitors a parameter corresponding to the heater's power consumption and provides a frequency compensation signal to the input of a frequency compensator according to a relationship derived between the monitored parameter and the frequency compensation signal required for a given crystal oscillator. The monitoring parameter corresponding to the power consumption of the heater is determined by measuring the voltage across a resistor connected in series with the heater, where a varying potential indicates a varying current consumption at a constant supply.

[0004] To solve the above-mentioned problems of the prior art, the present invention provides an oscillator device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 6,784,756 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides an oscillator device that senses transient temperature changes in the resonator to achieve temperature post-compensation without measuring power consumption. [Means for solving the problem]

[0007] In one embodiment of the present invention, the oscillator device is placed in an environment having an ambient temperature. The oscillator device includes a heater, an oscillator, and a temperature control circuit. The oscillator is configured to generate a first clock signal whose frequency depends on the ambient temperature. The temperature control circuit is directly electrically connected to the heater. The temperature control circuit is configured to detect the ambient temperature, generate an input voltage depending on the ambient temperature, and supply the input voltage to the heater. The temperature control circuit includes a metal-oxide-semiconductor field-effect transistor (MOSFET) and a temperature detection circuit. The drain of the MOSFET is directly electrically connected to the heater. The MOSFET and the heater are electrically connected between a high-voltage terminal and a low-voltage terminal. The temperature detection circuit is electrically connected to the gate of the MOSFET.

[0008] In one embodiment of the present invention, the oscillator device further includes an analog-to-digital converter (ADC) and a communication interface. The ADC is electrically connected to the heater and the temperature control circuit and configured to receive and convert an input voltage into a digital voltage signal. The communication interface is electrically connected to the ADC.

[0009] In one embodiment of the present invention, the oscillator device further includes an ADC, a processor, and a communication interface. The ADC is electrically connected to the heater and the temperature control circuit and configured to receive and convert an input voltage into a digital voltage signal. The processor is electrically connected to the ADC and configured to receive the digital voltage signal. The processor is configured to convert the digital voltage signal into a frequency-compensated signal based on a voltage-frequency relationship associated with the input voltage. The communication interface is electrically connected to the processor.

[0010] In one embodiment of the present invention, the oscillator device further includes an ADC, a processor, and a phase-locked loop (PLL). The ADC is electrically connected to the heater and the temperature control circuit and configured to receive and convert an input voltage into a digital voltage signal. The processor is electrically connected to the ADC and configured to receive the digital voltage signal. The processor is also configured to convert the digital voltage signal into a frequency compensation signal based on a voltage-frequency relationship associated with the input voltage. The PLL is electrically connected to the processor and the oscillator and configured to receive the frequency compensation signal and the first clock signal. The PLL is also configured to change the phase of the first clock signal based on the frequency compensation signal to generate a second clock signal.

[0011] In one embodiment of the present invention, the voltage-frequency relationship is related to the time rate of change of the digital voltage signal.

[0012] In one embodiment of the present invention, the voltage-frequency relationship is related to a linear combination of polynomials for the digital voltage signal.

[0013] In one embodiment of the present invention, the MOSFET is a P-channel Metal-Oxide-Semiconductor Field-Effect Transistor (PMOSFET), the source of the PMOSFET is electrically connected to the high-voltage terminal, and the heater is electrically connected to the low-voltage terminal.

[0014] In one embodiment of the present invention, the MOSFET is an N-channel Metal-Oxide-Semiconductor-Field-Effect-Transistor (NMOSFET), the source of the NMOSFET is electrically connected to the low-voltage terminal, and the heater is electrically connected to the high-voltage terminal. [Effects of the Invention]

[0015] In other words, the oscillator device of the present invention reduces the frequency fluctuation of the first clock signal caused by changes in ambient temperature by supplying an input voltage to the heater, and by using the input voltage as a physical quantity, detects temperature changes in the transient state of the oscillator device without measuring power consumption, thereby achieving temperature post-compensation.

[0016] In order to make the technical contents, features and achieved effects of the present invention easier to understand, the following detailed description of the embodiments accompanied with the accompanying drawings will be given. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating an oscillation device according to a first embodiment of the present invention. [Figure 2] 1 is a diagram showing a curve representing the relationship between the input voltage and the ambient temperature of an oscillator device according to an embodiment of the present invention. [Figure 3] FIG. 4 is a diagram illustrating an oscillation device according to a second embodiment of the present invention. [Figure 4]3A and 3B are diagrams showing curves representing the relationship between time and a digital voltage signal of an oscillator device according to an embodiment of the present invention and the relationship between time and a first clock signal. [Figure 5] FIG. 2 is a curve showing the relationship between ambient temperature and time according to the present invention. [Figure 6] FIG. 10 is a diagram illustrating an oscillation device according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a diagram illustrating an oscillation device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Embodiments of the present invention are further described below in conjunction with the associated figures. Wherever possible, the same reference numerals are used in the drawings and the specification to refer to the same or like parts. In the drawings, shapes and thicknesses may be exaggerated for clarity and convenience. The description is directed in particular to elements forming part of, or cooperating more directly with, the method and apparatus of the present invention. Elements not specifically shown in the drawings or described in the specification may be understood to be in forms known to those skilled in the art. Various changes and modifications will become apparent to those skilled in the art once they have read the present teachings.

[0019] Unless otherwise specified, some conditional phrases or particles, such as "can," "could," "might," or "may," may be interpreted as referring to features, elements, or steps that typically describe embodiments of the invention but may be unnecessary. In other embodiments, these features, elements, or steps may be unnecessary.

[0020] The references "in one embodiment" or "in one embodiment" in the text refer to a particular component, structure, or feature associated with at least one embodiment. Thus, the appearances of "in one embodiment" or "in one embodiment" in multiple places in the text do not necessarily refer to the same embodiment.

[0021] Although certain terms are used in the specification and claims to refer to particular components, those skilled in the art will understand that components may be referred to by different names. This disclosure does not intend to distinguish between components that differ in name but not function. The term "comprises" in this specification and claims is used in an open-ended manner, i.e., is intended to be non-limiting to the listed items. Furthermore, terms such as "coupled," "couples," and "coupling" include any direct and indirect connection. Thus, when this disclosure describes a first device being coupled to a second device, this indicates that the first device may be directly or indirectly connected to the second device via electrical connection, wireless communication, optical communication, or other signal connection, with or without any other intermediary device or connection means.

[0022] In particular, the examples described below are illustrative only. Those skilled in the art will readily recognize that many modifications and variations can be made to the apparatus and methods while retaining the teachings of the invention. Accordingly, the following disclosure should be construed as limited only by the scope of the appended claims. Unless expressly stated otherwise throughout the patent application and claims, the terms "a," "an," and "said" include "one or at least one" of that element or component. Furthermore, throughout the patent application and claims, the singular also includes the description of plural elements or components, unless the context clearly excludes the plural. The meaning of each term used in the claims and specification refers to its ordinary meaning as known to those skilled in the art, unless a special note is added to that meaning. Some terms used to describe the invention are discussed to guide practitioners of the invention. All examples herein are not intended to limit the scope of the invention claims.

[0023] Throughout this specification and claims, when a component is described as being "disposed on," "located above," "connected to," "engaged with," or "coupled" to another component, it will be understood that it can be directly disposed on, directly connected to, or directly engaged with the other component, or that intervening components may be present. In contrast, when a component is described as being "directly on," "directly connected to," or "directly engaged with," there are no intervening components.

[0024] Next, we will describe an oscillator device that supplies an input voltage to a heater to reduce frequency fluctuations in a first clock signal caused by changes in ambient temperature, and uses the input voltage as a physical quantity to sense temperature changes in the transient state of a resonator without measuring power consumption, thereby achieving temperature post-compensation.

[0025] FIG. 1 is a diagram illustrating an oscillator device according to a first embodiment of the present invention. FIG. 2 is a curve illustrating the relationship between the input voltage and ambient temperature of an oscillator device according to one embodiment of the present invention. Please refer to FIG. 1 to introduce an oscillator device 1. The oscillator device 1 is placed in an environment having an ambient temperature A and includes a heater 10, an oscillator 11, and a temperature control circuit 12. The temperature control circuit 12 is directly electrically connected to the heater 10. The oscillator 11 generates a first clock signal C1 whose frequency depends on the ambient temperature. The temperature control circuit 12 detects the ambient temperature A and generates an input voltage Vin that depends on the ambient temperature. The temperature control circuit 12 supplies the input voltage Vin to the heater 10 to reduce frequency fluctuations of the first clock signal C1 caused by fluctuations in the ambient temperature.

[0026] The primary purpose of temperature post-compensation is to establish a correlation between frequency and ambient temperature. However, relying solely on ambient temperature cannot adequately characterize the state of oscillator 1 due to thermodynamic processes. Even when the ambient temperature eventually stabilizes, oscillator 1 remains in a non-equilibrium thermal state. To sense transient temperature changes in oscillator 1, the input voltage Vin can be measured instead of directly measuring the temperature of oscillator 11. Under temperature control, the temperature change of oscillator 11 is only a few degrees Celsius. Therefore, the resolution for sensing temperature changes is reduced. The input voltage Vin is related to a control voltage managed by temperature control circuit 12. As shown in Figure 2, the voltage amplitude can range from 0 to 2 volts during ambient temperature fluctuations from -40°C to 95°C. As a result, a parameter is derived from the input voltage Vin. By measuring this parameter along with the frequency and ambient temperature, temperature post-compensation can be achieved dynamically or statically.

[0027] The temperature control circuit 12 includes a MOSFET 120 and a temperature detection circuit 121. The drain of the MOSFET 120 is directly electrically connected to the heater 10. The MOSFET 120 and the heater 10 are electrically connected between a first voltage terminal having a first voltage V1 and a second voltage terminal having a second voltage V2. The temperature detection circuit 121 is electrically connected to the gate and drain of the MOSFET 120 and the heater 10. If the MOSFET 120 is a PMOSFET, the source of the PMOSFET is electrically connected to the high-voltage terminal, which is the second voltage terminal, and the heater 10 is electrically connected to the low-voltage terminal, which is the first voltage terminal. If the MOSFET 120 is an NMOSFET, the source of the NMOSFET is electrically connected to the low-voltage terminal, which is the second voltage terminal, and the heater 10 is electrically connected to the high-voltage terminal, which is the first voltage terminal. The temperature detection circuit 121 detects the ambient temperature and receives an input voltage Vin to adjust the gate voltage of the MOSFET 120 based on the ambient temperature and the input voltage Vin. The MOSFET 120, driven by the temperature detection circuit 121, receives the second voltage and generates the input voltage Vin.

[0028] FIG. 3 is a diagram illustrating an oscillator device according to a second embodiment of the present invention. Referring to FIG. 3, the oscillator device 1 of the second embodiment differs from the first embodiment in that it further includes an ADC 13 and a communication interface 14. The communication interface 14 may be, but is not limited to, an Inter-Interconnected Circuit (I2C) bus or a serial peripheral interface (SPI) bus. The ADC 13 is electrically connected to the heater 10 and the temperature control circuit 12. The communication interface 14 is electrically connected to the ADC 13. The ADC 13 receives an input voltage Vin, converts it into a digital voltage signal D conforming to the communication protocol of the communication interface 14, and outputs the digital voltage signal D via the communication interface 14. The other components of the embodiment of FIG. 3 have already been described, so they will not be described again here. FIG. 4 is a graph illustrating the relationship between the digital voltage signal and time and the relationship between the first clock signal and time of an oscillator device according to one embodiment of the present invention. FIG. 5 is a graph illustrating the relationship between the ambient temperature and time of the present invention. As shown in FIGS. 4 and 5, when the ambient temperature stabilizes at 25°C, both the frequency and the digital voltage signal D continue to change. This observation indicates that the input voltage Vin can serve as a parameter for detecting whether the oscillator is in thermal equilibrium with the ambient temperature without measuring the power consumption.

[0029] FIG. 6 illustrates an oscillator device according to a third embodiment of the present invention. Referring to FIG. 6, the oscillator device 1 of the third embodiment differs from the first embodiment in that it further includes an ADC 13, a processor 15, and a communication interface 16. The communication interface 16 may be, but is not limited to, an I2C bus or an SPI bus. The ADC 13 is electrically connected to the heater 10 and the temperature control circuit 12. The processor 15 is electrically connected to the ADC 13. The communication interface 16 is electrically connected to the processor 15. The ADC 13 receives an input voltage Vin and converts it into a digital voltage signal D. The processor 15 receives the digital voltage signal D and converts it into a frequency compensation signal FC that conforms to the communication protocol of the communication interface 16 based on a voltage-frequency relationship associated with the input voltage Vin. In some embodiments, the voltage-frequency relationship is related to the time rate of change of the digital voltage signal D. For example, the voltage-frequency relationship is related to a linear combination of polynomials for the digital voltage signal D. The processor 15 outputs the digital voltage signal D via the communication interface 16. The other components of the embodiment of FIG. 6 have already been described, and therefore will not be described again here.

[0030] FIG. 7 is a diagram illustrating an oscillator device according to a fourth embodiment of the present invention. Referring to FIG. 7, the oscillator device 1 of the fourth embodiment differs from the first embodiment in that it further includes an ADC 13, a processor 17, and a PLL 18. The ADC 13 is electrically connected to the heater 10 and the temperature control circuit 12. The processor 17 is electrically connected to the ADC 13. The PLL 18 is electrically connected to the processor 17 and the oscillator 11. The ADC 13 receives an input voltage Vin and converts it into a digital voltage signal D. The processor 17 receives the digital voltage signal D. The processor 17 converts the digital voltage signal D into a frequency compensation signal FC based on a voltage-frequency relationship associated with the input voltage Vin. In some embodiments, the voltage-frequency relationship is related to the time rate of change of the digital voltage signal D. For example, the voltage-frequency relationship is related to a linear combination of polynomials for the digital voltage signal D. The PLL 18 receives the frequency compensation signal FC and the first clock signal C1 and changes the phase of the first clock signal C1 based on the frequency compensation signal FC to generate a second clock signal C2 whose frequency is closer to the reference frequency than the frequency of the first clock signal C1. The reference frequency is a standard frequency. For example, the standard frequency may be derived from a global positioning system (GPS). The other components of the embodiment of Figure 7 have already been described and will not be described again here.

[0031] According to the above-described embodiment, the oscillator device of the present invention reduces the frequency fluctuation of the first clock signal caused by changes in ambient temperature by supplying an input voltage to the heater, and senses the temperature change in the transient state of the oscillator device by using the input voltage as a physical quantity, thereby achieving temperature post-compensation.

[0032] The above-described embodiments are merely illustrative of the present invention and do not limit the scope of the present invention. Therefore, any equivalent modifications or variations based on the shape, structure, features, or spirit disclosed by the present invention are included within the scope of the claims of the present invention. [Explanation of symbols]

[0033] 1. Oscillator 10. Heater 11 Oscillators 12 Temperature control circuit 120 MOSFET 121 Temperature detection circuit 13 ADC 14 Communication Interface 15 processors 16 Communication Interface 17 processors 18 PLL A Ambient temperature C1 First clock signal C2 Second clock signal D Digital voltage signal FC frequency compensation signal Vin Input voltage V1 First voltage V2 Second voltage

Claims

1. 1. An oscillator device disposed in an environment having an ambient temperature, a heater, an oscillator, and a temperature control circuit; the oscillator is configured to generate a first clock signal whose frequency is dependent on the ambient temperature; the temperature control circuit is electrically connected directly to the heater and configured to detect the ambient temperature, generate an input voltage dependent on the ambient temperature, and supply the input voltage to the heater; the temperature control circuit includes a metal-oxide-semiconductor field-effect transistor (MOSFET) and a temperature detection circuit; a drain of the MOSFET is directly electrically connected to the heater, and the MOSFET and the heater are electrically connected between a high voltage terminal and a low voltage terminal; The oscillation device is characterized in that the temperature detection circuit is electrically connected to the gate of the MOSFET.

2. further including an analog-to-digital converter (ADC) and a communication interface; the ADC is electrically connected to the heater and the temperature control circuit and configured to receive and convert the input voltage into a digital voltage signal; The oscillator device according to claim 1 , wherein the communication interface is electrically connected to the ADC.

3. further comprising an analog-to-digital converter (ADC), a processor, and a communication interface; the ADC is electrically connected to the heater and the temperature control circuit and configured to receive and convert the input voltage into a digital voltage signal; the processor is electrically connected to the ADC and configured to receive the digital voltage signal, the processor configured to convert the digital voltage signal into a frequency compensated signal based on a voltage-frequency relationship associated with the input voltage; The oscillator device according to claim 1 , wherein the communication interface is electrically connected to the processor.

4. further comprising an analog-to-digital converter (ADC), a processor, and a phase-locked loop (PLL); the ADC is electrically connected to the heater and the temperature control circuit and configured to receive and convert the input voltage into a digital voltage signal; the processor is electrically connected to the ADC and configured to receive the digital voltage signal and to convert the digital voltage signal into a frequency-compensated signal based on a voltage-frequency relationship associated with the input voltage; 2. The oscillator device of claim 1, wherein the PLL is electrically connected to the processor and the oscillator, and is configured to receive the frequency compensation signal and the first clock signal, and is configured to change the phase of the first clock signal based on the frequency compensation signal to generate a second clock signal.

5. 5. The oscillator device of claim 4, wherein the voltage-frequency relationship is related to the time rate of change of the digital voltage signal.

6. 5. The oscillator device of claim 4, wherein the voltage-frequency relationship is related to a linear combination of polynomials for the digital voltage signal.

7. 2. The oscillator device of claim 1, wherein the MOSFET is a P-channel Metal-Oxide-Semiconductor Field-Effect Transistor (PMOSFET), a source of the PMOSFET is electrically connected to the high-voltage terminal, and the heater is electrically connected to the low-voltage terminal.

8. 2. The oscillator device of claim 1, wherein the MOSFET is an N-channel Metal-Oxide-Semiconductor Field-Effect Transistor (NMOSFET), a source of the NMOSFET is electrically connected to the low-voltage terminal, and the heater is electrically connected to the high-voltage terminal.

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