WO2024205095A1 - Electronic device, and method for controlling crystal oscillator of electronic device - Google Patents

Abstract

This electronic device may comprise: a processor; a crystal oscillator (XO) generating a reference clock for generating a signal with a reference frequency; and a memory. The processor can: determine a trim value so that a clock generator can generate a constant frequency in a sleep mode; apply the determined trim value on the basis that the clock generator enters the sleep mode; perform calibration while the clock generator is in the sleep mode; determine a control coefficient causing a frequency error in the crystal oscillator to be below a threshold; store a determined control coefficient value in the memory; and change the control coefficient to the determined control coefficient value in the sleep mode on the basis that the state of the clock generator switches from an active mode to the sleep mode.

Description

Electronic devices and methods for controlling crystal oscillators (XOs) in electronic devices

This article is about electronic devices, and for example how they control their crystal oscillators (XOs) under certain conditions (e.g., sleep mode).

Communication systems generally require crystal oscillators, which have more accurate and stable frequencies than inaccurate quartz crystals, to generate signals with specific frequencies. A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to generate an electrical signal with a specific frequency. The most common type of piezoelectric resonator used is a quartz resonator, so the oscillator circuit called a quartz resonator is called a crystal oscillator.

Environmental changes in temperature, humidity, pressure, and vibration can change the resonant frequency of a crystal oscillator. To overcome environmental changes and reduce or improve the frequency shift of a crystal oscillator, common solutions are temperature compensated crystal oscillators (TCXOs) and digitally compensated crystal oscillators (DCXOs). A temperature compensated crystal oscillator (TCXO) uses analog frequency compensation dictated by an analog voltage generated by a temperature sensor to adjust a voltage variable capacitor. A digitally compensated crystal oscillator (DCXO) can correct the frequency using a digitally controlled capacitor bank.

Wireless communication devices may require an accurate timing source for stable communication and system operation. Crystal (Quartz Crystal Unit, expressed as XTAL) refers to a resonator that generates an oscillation frequency using an externally applied electrical signal. In addition, OSC (oscillator) refers to a quartz crystal oscillator and refers to an electronic oscillator circuit that uses a crystal to generate a reference frequency. OSC (oscillator) refers to a device that uses the piezoelectric effect to generate electricity when pressure is applied by inserting a crystal and an oscillation circuit into one CAN and vibrates when electricity is applied. The crystal can be made to vibrate constantly through an appropriate control circuit, and this vibration can be detected and used as a clock for a digital circuit and a reference clock for a PLL in an RF circuit. Types of OSC include TCXO (Temperature-Compensated Crystal Oscillator), VCXO (Voltage-Controlled Crystal Oscillator), and VCTCXO (Voltage-Controlled Temperature-Compensated Crystal Oscillator). Recently, for price competitiveness, a structure that uses crystal and oscillator circuit IC (e.g. PMK package) separately is being widely used.

Crystals have the characteristic of vibrating at a certain frequency according to the load capacitance set at the design stage. Crystals also have the characteristic of causing frequency deviation depending on the surrounding temperature and pressure. Crystals have an initial error during the crystal production process, and the initial error can be compensated for by adjusting the load capacitance value of the oscillation circuit IC for accurate resonance.

The XO used below can mean a crystal oscillator. XO stands for quartz crystal oscillator. XO can utilize the piezoelectric effect, which generates electricity when pressure is applied and vibrates when electricity is applied.

An electronic device can check the frequency of a signal broadcast by a base station by changing the frequency of a reference signal used in the operation of changing a signal broadcast by a base station into a baseband signal for frequency synchronization within a pre-specified range using automatic frequency control (AFC).

However, due to a problem with the DCXO (digitally compensated crystal oscillator), the frequency of the reference signal may be different from the intended frequency. For example, if an error occurs in the control of the communication processor, the DCXO may generate a clock different from the reference clock for generating the reference frequency, so that a transceiver designed to generate a reference signal based on the reference clock of the DCXO may generate a signal having a frequency different from the intended frequency. Furthermore, due to the aging of various components included in the DCXO (e.g., crystals or devices connected to the crystal), a situation may arise where the clock transmitted to the transceiver is different from the reference clock. In other words, the electronic device must find the optimized load capacitance for the mounted XO to generate the set frequency. The set frequency may mean the frequency at which the electronic device can generate a stable clock. If the optimized load capacitance for the XO mounted on the electronic device is not found and an error occurs in the early stage of the process, it may be difficult for the electronic device to generate a stable clock.

In addition, XO can have different frequencies depending on the surrounding temperature. The relationship between the frequency error occurring in XO and the temperature is called the FT function, and the FT function can be expressed as shown in the mathematical expression 1 below.

[Mathematical formula 1]

f(t)=C3(t-t0)^3+C2(t-t0)^2+C1(t-t0)+C0

f represents the correction frequency of the independent variables C0, C1, C2, and C3, and t0 is the initial temperature change (or inflection temperature / inflection point, in some cases t0 has a variation and is the zero temperature or the initial temperature of the calibration process). t0 may vary depending on the manufacturing process of the crystal. Once t0 is specified, in the situation where t = t0, the value of mathematical expression 1 can be determined as C0. The value of f(t) can mean the error of the frequency. In the situation where t is t0, the value of f(t) can be determined by the coefficient C0. The frequency error can be reduced as the coefficient C0 approaches 0. In the situation where t is not t0, the frequency error can be reduced by adjusting the coefficients (C0, C1, C2, C3) of other FT functions.

The coefficients of the FT function (C0, C1, C2, C3) can have values at which field calibration is continuously performed through communication with the base station when the sample is connected to the receiver. The coefficients of the FT function can have different values depending on the temperature of the sample. t0 represents an inflection point and can represent an inflection point of a graph on the FT function. The FT function can have a graph in the form of a cubic function, and the closer the frequency error value corresponding to the inflection point (e.g., t=t0) is to 0, the more the overall frequency error can be reduced. To reduce the frequency error, calibration (coarse calibration) for XO can be performed.

A clock generator can have different load capitance values in the active and sleep states. The clock generator can control the load capitance for the XO to achieve optimal resonance based on the trim value. If the trim value changes, the load capitance value of the clock generator changes, which may make it difficult to control the XO to achieve optimal resonance. If it is difficult for the XO to achieve optimal resonance, an error may occur in the frequency generated by the clock generator. An electronic device can have a trim value determined in the active state. The load capitance value may change when the electronic device changes to the sleep state. If the trim value determined in the active state is used as is, it may be difficult to control the XO to achieve optimal resonance.

An electronic device according to this document can store trim values in memory so that a clock generator can generate a constant frequency when in a sleep state rather than an active state.

Methods and electronic devices for reducing XO errors according to various embodiments of this document are intended to present a method for maintaining optimal load capacitance even in a sleep state and a method for optimizing the coefficients of an FT function in a situation where disappointment cannot be accessed.

An electronic device may include a processor, a crystal oscillator (XO) that generates a reference clock for generating a signal having a reference frequency, and a memory. The processor may determine a trim value so that the clock generator can constantly generate a frequency in a sleep mode, apply the determined trim value based on the clock generator entering the sleep mode, perform calibration while the clock generator is in the sleep mode, determine a control coefficient that makes a frequency error of the crystal oscillator less than or equal to a threshold value, store the determined control coefficient value in the memory, and change the control coefficient to the control coefficient value determined in the sleep mode based on the state of the clock generator switching from an active mode to a sleep mode.

A method for controlling a crystal oscillator (XO) of an electronic device may include an operation of performing calibration while a clock generator is in a sleep mode, an operation of determining a control coefficient that causes a frequency error of the crystal oscillator to be expressed along the y-axis and become less than or equal to a threshold value, an operation of storing the determined control coefficient value in a memory, and an operation of changing the control coefficient to the determined control coefficient value while in the sleep mode based on a state of the clock generator being switched from an active mode to a sleep mode.

According to one embodiment, an electronic device may provide a method for maintaining an optimal load capacitance even in a sleep state and a method for optimizing the coefficients of an FT function in a situation where a failure cannot be accessed. Here, the sleep state may be a state different from an active state. The sleep state may include, for example, a situation where the electronic device is in airplane mode.

A method and electronic device for reducing XO error according to various embodiments of this document propose a method of securing the values of coefficients to be used during sleep through separate coarse calibration, thereby maintaining load capacitance even in a sleep state.

FIG. 1 is a block diagram of an electronic device within a network environment according to various embodiments.

Figure 2 is a circuit diagram showing an XO and a clock generator according to a comparative example.

FIG. 3A is a diagram illustrating an electronic device and a base station according to one embodiment.

FIG. 3b is a block diagram of an electronic device according to one embodiment.

Figure 4 is a graph showing the initial process error according to a comparative example.

FIG. 5 illustrates a first embodiment in which the coefficients of the FT function can be updated according to temperature when the electronic device is in a sleep state.

FIG. 6 illustrates a second embodiment in which the coefficients of the FT function can be updated according to temperature when the electronic device is in a sleep state.

FIG. 7 is a flowchart illustrating a method for controlling a crystal oscillator (XO) of an electronic device according to one embodiment.

FIG. 8 is a flowchart illustrating a method for controlling a crystal oscillator (XO) of an electronic device according to one embodiment.

FIG. 1 is a block diagram of an electronic device (101) in a network environment (100) according to various embodiments. Referring to FIG. 1, in the network environment (100), the electronic device (101) may communicate with the electronic device (102) via a first network (198) (e.g., a short-range wireless communication network), or may communicate with at least one of the electronic device (104) or the server (108) via a second network (199) (e.g., a long-range wireless communication network). According to one embodiment, the electronic device (101) may communicate with the electronic device (104) via the server (108). According to one embodiment, the electronic device (101) may include a processor (120), a memory (130), an input module (150), an audio output module (155), a display module (160), an audio module (170), a sensor module (176), an interface (177), a connection terminal (178), a haptic module (179), a camera module (180), a power management module (188), a battery (189), a communication module (190), a subscriber identification module (196), or an antenna module (197). In some embodiments, the electronic device (101) may omit at least one of these components (e.g., the connection terminal (178)), or may have one or more other components added. In some embodiments, some of these components (e.g., the sensor module (176), the camera module (180), or the antenna module (197)) may be integrated into one component (e.g., the display module (160)).

The processor (120) may control at least one other component (e.g., a hardware or software component) of an electronic device (101) connected to the processor (120) by executing, for example, software (e.g., a program (140)), and may perform various data processing or calculations. According to one embodiment, as at least a part of the data processing or calculations, the processor (120) may store a command or data received from another component (e.g., a sensor module (176) or a communication module (190)) in a volatile memory (132), process the command or data stored in the volatile memory (132), and store result data in a nonvolatile memory (134). According to one embodiment, the processor (120) may include a main processor (121) (e.g., a central processing unit or an application processor) or an auxiliary processor (123) (e.g., a graphics processing unit, a neural processing unit (NPU), an image signal processor, a sensor hub processor, or a communication processor) that can operate independently or together with the main processor (121). For example, when the electronic device (101) includes the main processor (121) and the auxiliary processor (123), the auxiliary processor (123) may be configured to use less power than the main processor (121) or to be specialized for a given function. The auxiliary processor (123) may be implemented separately from the main processor (121) or as a part thereof.

The auxiliary processor (123) may control at least a portion of functions or states associated with at least one of the components of the electronic device (101) (e.g., the display module (160), the sensor module (176), or the communication module (190)), for example, on behalf of the main processor (121) while the main processor (121) is in an inactive (e.g., sleep) state, or together with the main processor (121) while the main processor (121) is in an active (e.g., application execution) state. In one embodiment, the auxiliary processor (123) (e.g., an image signal processor or a communication processor) may be implemented as a part of another functionally related component (e.g., a camera module (180) or a communication module (190)). In one embodiment, the auxiliary processor (123) (e.g., a neural network processing device) may include a hardware structure specialized for processing artificial intelligence models. The artificial intelligence models may be generated through machine learning. Such learning may be performed, for example, in the electronic device (101) itself on which the artificial intelligence model is executed, or may be performed through a separate server (e.g., server (108)). The learning algorithm may include, for example, supervised learning, unsupervised learning, semi-supervised learning, or reinforcement learning, but is not limited to the examples described above. The artificial intelligence model may include a plurality of artificial neural network layers. The artificial neural network may be one of a deep neural network (DNN), a convolutional neural network (CNN), a recurrent neural network (RNN), a restricted Boltzmann machine (RBM), a deep belief network (DBN), a bidirectional recurrent deep neural network (BRDNN), deep Q-networks, or a combination of two or more of the above, but is not limited to the examples described above. In addition to the hardware structure, the artificial intelligence model may additionally or alternatively include a software structure.

The memory (130) can store various data used by at least one component (e.g., processor (120) or sensor module (176)) of the electronic device (101). The data can include, for example, software (e.g., program (140)) and input data or output data for commands related thereto. The memory (130) can include volatile memory (132) or nonvolatile memory (134).

The program (140) may be stored as software in memory (130) and may include, for example, an operating system (142), middleware (144), or an application (146).

The input module (150) can receive commands or data to be used in a component of the electronic device (101) (e.g., a processor (120)) from an external source (e.g., a user) of the electronic device (101). The input module (150) can include, for example, a microphone, a mouse, a keyboard, a key (e.g., a button), or a digital pen (e.g., a stylus pen).

The audio output module (155) can output an audio signal to the outside of the electronic device (101). The audio output module (155) can include, for example, a speaker or a receiver. The speaker can be used for general purposes such as multimedia playback or recording playback. The receiver can be used to receive an incoming call. According to one embodiment, the receiver can be implemented separately from the speaker or as a part thereof.

The display module (160) can visually provide information to an external party (e.g., a user) of the electronic device (101). The display module (160) can include, for example, a display, a holographic device, or a projector and a control circuit for controlling the device. According to one embodiment, the display module (160) can include a touch sensor configured to detect a touch, or a pressure sensor configured to measure the intensity of a force generated by the touch.

The audio module (170) can convert sound into an electrical signal, or vice versa, convert an electrical signal into sound. According to one embodiment, the audio module (170) can obtain sound through an input module (150), or output sound through an audio output module (155), or an external electronic device (e.g., an electronic device (102)) (e.g., a speaker or a headphone) directly or wirelessly connected to the electronic device (101).

The sensor module (176) can detect an operating state (e.g., power or temperature) of the electronic device (101) or an external environmental state (e.g., user state) and generate an electrical signal or data value corresponding to the detected state. According to one embodiment, the sensor module (176) can include, for example, a gesture sensor, a gyro sensor, a barometric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an IR (infrared) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor.

The interface (177) may support one or more designated protocols that may be used to directly or wirelessly connect the electronic device (101) with an external electronic device (e.g., the electronic device (102)). In one embodiment, the interface (177) may include, for example, a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, an SD card interface, or an audio interface.

The connection terminal (178) may include a connector through which the electronic device (101) may be physically connected to an external electronic device (e.g., the electronic device (102)). According to one embodiment, the connection terminal (178) may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (e.g., a headphone connector).

The haptic module (179) can convert an electrical signal into a mechanical stimulus (e.g., vibration or movement) or an electrical stimulus that a user can perceive through a tactile or kinesthetic sense. According to one embodiment, the haptic module (179) can include, for example, a motor, a piezoelectric element, or an electrical stimulation device.

The camera module (180) can capture still images and moving images. According to one embodiment, the camera module (180) can include one or more lenses, image sensors, image signal processors, or flashes.

The power management module (188) can manage power supplied to the electronic device (101). According to one embodiment, the power management module (188) can be implemented as, for example, at least a part of a power management integrated circuit (PMIC).

The battery (189) can power at least one component of the electronic device (101). In one embodiment, the battery (189) can include, for example, a non-rechargeable primary battery, a rechargeable secondary battery, or a fuel cell.

The communication module (190) may support establishment of a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device (101) and an external electronic device (e.g., the electronic device (102), the electronic device (104), or the server (108)), and performance of communication through the established communication channel. The communication module (190) may operate independently from the processor (120) (e.g., the application processor) and may include one or more communication processors that support direct (e.g., wired) communication or wireless communication. According to one embodiment, the communication module (190) may include a wireless communication module (192) (e.g., a cellular communication module, a short-range wireless communication module, or a GNSS (global navigation satellite system) communication module) or a wired communication module (194) (e.g., a local area network (LAN) communication module or a power line communication module). Among these communication modules, a corresponding communication module may communicate with an external electronic device (104) via a first network (198) (e.g., a short-range communication network such as Bluetooth, wireless fidelity (WiFi) direct, or infrared data association (IrDA)) or a second network (199) (e.g., a long-range communication network such as a legacy cellular network, a 5G network, a next-generation communication network, the Internet, or a computer network (e.g., a LAN or WAN)). These various types of communication modules may be integrated into a single component (e.g., a single chip) or implemented as multiple separate components (e.g., multiple chips). The wireless communication module (192) may use subscriber information (e.g., an international mobile subscriber identity (IMSI)) stored in the subscriber identification module (196) to identify or authenticate the electronic device (101) within a communication network such as the first network (198) or the second network (199).

The wireless communication module (192) can support a 5G network and next-generation communication technology after a 4G network, for example, NR access technology (new radio access technology). The NR access technology can support high-speed transmission of high-capacity data (eMBB (enhanced mobile broadband)), terminal power minimization and connection of multiple terminals (mMTC (massive machine type communications)), or high reliability and low latency (URLLC (ultra-reliable and low-latency communications)). The wireless communication module (192) can support, for example, a high-frequency band (e.g., mmWave band) to achieve a high data transmission rate. The wireless communication module (192) may support various technologies for securing performance in a high-frequency band, such as beamforming, massive multiple-input and multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, or large scale antenna. The wireless communication module (192) may support various requirements specified in an electronic device (101), an external electronic device (e.g., an electronic device (104)), or a network system (e.g., a second network (199)). According to one embodiment, the wireless communication module (192) can support a peak data rate (e.g., 20 Gbps or more) for eMBB realization, a loss coverage (e.g., 164 dB or less) for mMTC realization, or a U-plane latency (e.g., 0.5 ms or less for downlink (DL) and uplink (UL) each, or 1 ms or less for round trip) for URLLC realization.

The antenna module (197) can transmit or receive signals or power to or from the outside (e.g., an external electronic device). According to one embodiment, the antenna module (197) can include an antenna including a radiator formed of a conductor or a conductive pattern formed on a substrate (e.g., a PCB). According to one embodiment, the antenna module (197) can include a plurality of antennas (e.g., an array antenna). In this case, at least one antenna suitable for a communication method used in a communication network, such as the first network (198) or the second network (199), can be selected from the plurality of antennas by, for example, the communication module (190). A signal or power can be transmitted or received between the communication module (190) and the external electronic device through the selected at least one antenna. According to some embodiments, in addition to the radiator, another component (e.g., a radio frequency integrated circuit (RFIC)) can be additionally formed as a part of the antenna module (197).

According to various embodiments, the antenna module (197) may form a mmWave antenna module. According to one embodiment, the mmWave antenna module may include a printed circuit board, an RFIC positioned on or adjacent a first side (e.g., a bottom side) of the printed circuit board and capable of supporting a designated high-frequency band (e.g., a mmWave band), and a plurality of antennas (e.g., an array antenna) positioned on or adjacent a second side (e.g., a top side or a side) of the printed circuit board and capable of transmitting or receiving signals in the designated high-frequency band.

At least some of the above components may be connected to each other and exchange signals (e.g., commands or data) with each other via a communication method between peripheral devices (e.g., a bus, a general purpose input and output (GPIO), a serial peripheral interface (SPI), or a mobile industry processor interface (MIPI)).

In one embodiment, commands or data may be transmitted or received between the electronic device (101) and an external electronic device (104) via a server (108) connected to a second network (199). Each of the external electronic devices (102, or 104) may be the same or a different type of device as the electronic device (101). In one embodiment, all or part of the operations executed in the electronic device (101) may be executed in one or more of the external electronic devices (102, 104, or 108). For example, when the electronic device (101) is to perform a certain function or service automatically or in response to a request from a user or another device, the electronic device (101) may, instead of executing the function or service itself or in addition, request one or more external electronic devices to perform at least a part of the function or service. One or more external electronic devices that have received the request may execute at least a part of the requested function or service, or an additional function or service related to the request, and transmit the result of the execution to the electronic device (101). The electronic device (101) may provide the result, as is or additionally processed, as at least a part of a response to the request. For this purpose, cloud computing, distributed computing, mobile edge computing (MEC), or client-server computing technology may be used, for example. The electronic device (101) may provide an ultra-low latency service by using distributed computing or mobile edge computing, for example. In another embodiment, the external electronic device (104) may include an IoT (Internet of Things) device. The server (108) may be an intelligent server using machine learning and/or a neural network. According to one embodiment, the external electronic device (104) or the server (108) may be included in the second network (199). The electronic device (101) can be applied to intelligent services (e.g., smart home, smart city, smart car, or healthcare) based on 5G communication technology and IoT-related technology.

Electronic devices according to various embodiments disclosed in this document may be devices of various forms. The electronic devices may include, for example, portable communication devices (e.g., smartphones), computer devices, portable multimedia devices, portable medical devices, cameras, wearable devices, or home appliance devices. Electronic devices according to embodiments of this document are not limited to the above-described devices.

It should be understood that the various embodiments of this document and the terminology used herein are not intended to limit the technical features described in this document to specific embodiments, but include various modifications, equivalents, or substitutes of the embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more of the items, unless the context clearly dictates otherwise. In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" can include any one of the items listed together in the corresponding phrase, or all possible combinations thereof. Terms such as "first", "second", or "first" or "second" may be used merely to distinguish one component from another, and do not limit the components in any other respect (e.g., importance or order). When a component (e.g., a first) is referred to as "coupled" or "connected" to another (e.g., a second) component, with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

The term "module" used in various embodiments of this document may include a unit implemented in hardware, software or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit, for example. A module may be an integrally configured component or a minimum unit of the component or a part thereof that performs one or more functions. For example, according to one embodiment, a module may be implemented in the form of an application-specific integrated circuit (ASIC).

Various embodiments of the present document may be implemented as software (e.g., a program (140)) including one or more instructions stored in a storage medium (e.g., an internal memory (136) or an external memory (138)) readable by a machine (e.g., an electronic device (101)). For example, a processor (e.g., a processor (120)) of the machine (e.g., an electronic device (101)) may call at least one instruction among the one or more instructions stored from the storage medium and execute it. This enables the machine to operate to perform at least one function according to the at least one called instruction. The one or more instructions may include code generated by a compiler or code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-transitory' simply means that the storage medium is a tangible device and does not contain signals (e.g. electromagnetic waves), and the term does not distinguish between cases where data is stored semi-permanently or temporarily on the storage medium.

According to one embodiment, the method according to various embodiments disclosed in the present document may be provided as included in a computer program product. The computer program product may be traded between a seller and a buyer as a commodity. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., a compact disc read only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) via an application store (e.g., Play StoreTM) or directly between two user devices (e.g., smart phones). In the case of online distribution, at least a part of the computer program product may be at least temporarily stored or temporarily generated in a machine-readable storage medium, such as a memory of a manufacturer's server, a server of an application store, or an intermediary server.

According to various embodiments, each component (e.g., a module or a program) of the above-described components may include a single or multiple entities, and some of the multiple entities may be separately arranged in other components. According to various embodiments, one or more components or operations of the above-described components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, the multiple components (e.g., a module or a program) may be integrated into one component. In such a case, the integrated component may perform one or more functions of each of the multiple components identically or similarly to those performed by the corresponding component of the multiple components before the integration. According to various embodiments, the operations performed by the module, program, or other component may be executed sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

Figure 2 is a circuit diagram showing an XO and a clock generator according to a comparative example.

An electronic device according to a comparative example may include an XO (210) and a clock generator (220).

Wireless communication devices may require a source that provides accurate timing for a stable communication environment and system environment. A crystal oscillator (Quartz Crystal Unit, XTAL) may refer to a resonator that generates an oscillation frequency using an externally applied electrical signal. An oscillator (OSC) may refer to a circuit that uses a crystal oscillator to generate a reference frequency. An oscillator (OSC) can generate a signal by using the piezoelectric effect that generates electricity when pressure is applied and vibrates when electricity is applied conversely. An oscillator (OSC) can control a crystal to vibrate at a constant frequency using a circuit. An oscillator (OSC) can use the vibration generated by the crystal as a clock for a digital circuit. A crystal can vibrate at a constant frequency according to the load capacitance set at the design stage. There may be an initial error in the process stage, and in order for the signal to have the intended frequency, the electronic device can compensate for the initial error of the crystal by adjusting the value of the load capacitance of the oscillator circuit. Hereinafter, the crystal may be used as the term crystal oscillator (XO) (210).

The clock generator (220) can generate a clock at a constant frequency. The frequency of the generated clock can be determined by the value of the load capacitance. The value of the load capacitance can vary depending on the values of C_tune (222) and C_status (224).

C_status(224) may include a capacitance value determined according to a trim value of a crystal oscillator (XO)(210). C_tune(222) may include a capacitance value that is adjusted to maintain a constant load capacitance value in response to a change in C_status(224). For example, a clock generator(220) may require a load capacitance value of 5pF to generate a constant clock. In a situation where a load capacitance value of 5pF is required, if the value of C_status(224) is 3pF, the electronic device may control C_tune(222) to have a value of 2pF. If the value of C_status(224) changes to 3.5pF, the electronic device may control C_tune(222) to have a value of 1.5pF. The value of C_status(224) may be different when the clock generator is enabled and when it is in sleep state.

However, if the clock generator is in a sleep state and not in an activated state, it may be difficult to change the C_tune (222) value. If the value of C_status (224) changes in a sleep state in which it is difficult to change the C_tune (222) value, it may be difficult for the clock generator (220) to satisfy the load capacitance value required to generate a constant clock. The clock generator (220) may have difficulty generating a constant clock.

A factory tuning calibration can be performed on a crystal oscillator (XO). The tuning calibration can be used to determine the nominal frequency offset around C0 and t0 in the above equation (1). f represents the crystal frequencies of the independent variables C0, C1, C2, and C3, and t0 represents the initial temperature change (or inflection temperature / inflection point, in some cases ㅅ0 has a variation and can be the zero temperature or the initial temperature of the calibration process). t0 can vary slightly from product to product due to the manufacturing process of the crystal. When using an XO, the tuning value of C0 can be set to zero and thus removed from the temperature curve formula.

A general correction model can be a third-degree polynomial with five variables along with four independent variables as shown in Equation 1 above.

[Mathematical formula 1]

f(t)=C3(t-t0)^3+C2(t-t0)^2+C1(t-t0)+C0

f represents the correction frequency of the independent variables C0, C1, C2 and C3, _T0 is the initial temperature change (or inflection temperature / inflection point, in some cases t0 has a variation and is the zero temperature or the initial temperature of the calibration process). to may have some differences due to the manufacturing process.

In a sleep state, since the coefficients of the FT function cannot be changed, it may be difficult to update the coefficient values of the FT function to have an optimal load capacitance value according to temperature changes. The optimal load capacitance value may include a value that controls the clock generator (220) to generate a constant frequency. If the coefficients of the FT function cannot be changed, the clock generator (220) may not have an optimal load capacitance value, making it difficult to generate a constant frequency.

FIG. 3a is a diagram illustrating an electronic device and a base station according to one embodiment of the present document.

According to one embodiment, the base station (310) may be a base station supporting the first cellular communication. The first cellular communication may mean any one of various cellular communication methods that the electronic device (300) can support. For example, the first cellular communication may be any one of the 5th generation mobile communication methods (e.g., a communication method using FR1, which is a band below 6 GHz, or a communication method using FR2, which is a frequency band above 6 GHz). According to one embodiment, the base station (210) may be a base station that outputs a signal of the first frequency band (e.g., a frequency band above 6 GHz).

The electronic device (220) can perform registration on a cellular network and transmit and/or receive various data with an external electronic device (e.g., the electronic device (104) of FIG. 1) via a base station (310).

The electronic device (300) may search for a base station (310) included in the cellular network in order to attempt to register with the cellular network, and as the search for the base station (310) is completed, perform a registration procedure with the cellular network through the base station (310).

The electronic device (300) can receive a SS/PBCH block (synchronization signal/physical broadcast channel block) broadcast by the base station (310) before registering with the cellular network. The SS/PBCH block is data required when the electronic device (300) searches for the base station (310) to which it will be connected, and the SS/PBCH block can be broadcast by the base station (310) at a designated period (e.g., 20 ms).

The electronic device (300) can decode the SS/PBCH block and synchronize with the base station (310) based on the signal obtained through the decoding. The electronic device (300) can obtain a master information block (MIB) through a physical broadcast channel (PBCH) included in the SS/PBCH block. The electronic device (300) can obtain identification information (or physical identification information) of the base station (310), information related to a paging message, and/or a system frame number of the SS/PBCH block through the master information block.

The electronic device (300) can connect to the base station (310) based on the acquired information and perform synchronization of the downlink with the base station (310). The electronic device (300) can perform random access to perform synchronization of the uplink with the base station (310), and when the random access procedure is completed, can perform a registration procedure with the cellular network. After the electronic device (300) is registered with the cellular network, it can transmit or receive data to or from an external electronic device (104).

The procedures described above may be procedures implemented on the premise that the electronic device (300) performs a search for the base station (310). In order to perform a search for the base station (310), the electronic device (300) may perform a procedure for discovering a signal (e.g., SS/PBCH) broadcast by the base station (310) in a pre-designated frequency band. The electronic device (300) may check the characteristics of the signal broadcast by the base station (310) (e.g., frequency band of the signal, carrier frequency) and perform frequency synchronization to match the frequency of the signal broadcast by the base station (310) with the frequency of a reference signal used in a communication circuit of the electronic device (300). Frequency synchronization is an essential procedure for converting a signal broadcast by the base station (310) into a baseband signal. Frequency synchronization is described in detail in FIG. 3.

FIG. 3 is a block diagram of an electronic device according to one embodiment of the present document.

Referring to FIG. 3, the electronic device (300) may include a communication processor (330), a clock generator (335), XO (crystal oscillators) (340), a transceiver (350), and/or an antenna (360). The XO may include an X-TAL (crystal or passive oscillator).

According to one embodiment, the communication processor (320) may receive or transmit control data or user data via cellular wireless communication (e.g., 2nd generation mobile communication, 3rd generation mobile communication, 4th generation mobile communication, and/or 5th generation mobile communication). The communication processor (320) may establish a cellular communication connection with a base station (e.g., the base station (310) of FIG. 2) via the control data, and may transmit data received from an application processor (e.g., the processor (120) of FIG. 1) to the base station via the established cellular communication, or transmit data received from the base station to the application processor (120).

According to one embodiment, the transceiver (350) may perform various operations for processing a signal received from the communication processor (320). For example, the transceiver (350) may perform a modulation operation on a signal received from the communication processor (320). For example, the transceiver (350) may perform a frequency modulation operation for converting a baseband signal into a radio frequency (RF) signal used for cellular communication.

The transceiver (350) may also perform a demodulation operation on a signal received from the outside through the antenna (360). For example, the transceiver (350) may perform a frequency demodulation operation that converts a radio frequency (RF) signal into a baseband signal.

The transceiver (350) may include a mixer (351) that converts the frequency of a signal transmitted by a base station (310) having a radio frequency (RF) into a baseband signal based on the difference between a signal received through an antenna (360) and a reference signal output by a local oscillator.

The transceiver (350) may include a local oscillator (353) that transmits a reference signal to the mixer (351) and a PLL (phase locked loop (355) that maintains the frequency of the reference signal output by the local oscillator (353) within a certain range.

The crystal oscillator (XO) (340) may include a crystal element that vibrates at a specific frequency corresponding to the voltage applied by the communication processor (320). The frequency band of the vibration of the crystal element may vary depending on the temperature. Therefore, the XO (340) may adjust the frequency band of the signal by using an element having different impedance depending on the temperature value. The XO (340) may function as a reference clock so that a signal used by the transceiver (350) has a designated frequency band. The transceiver (350) may generate a signal of a required frequency band (e.g., a reference frequency) based on the reference clock, and may convert a signal received through the antenna (360) into a baseband signal.

The communication processor (320) may perform a series of operations to check the characteristics of a signal broadcast by the base station (310) in order to search for the base station (310). The communication processor (320) may control the XO (340) to generate a reference clock having a reference frequency obtained in various ways (e.g., checking carrier frequency information corresponding to channels supported by a network that is stored in advance on the electronic device (300). The communication processor (320) may control the transceiver (350) to generate a signal having a reference frequency by using the reference clock generated by the XO (340). For example, the transceiver (350) may control the PLL (355) and the local oscillator (353) to generate a signal having a reference frequency by using the reference clock. The communication processor (320) can control the transceiver (350) to convert a signal received through the antenna (360) into a baseband signal based on a signal having a reference frequency. For example, the transceiver (350) can generate a baseband signal by down converting a signal received through the antenna (360) using a signal having a reference frequency output from a local oscillator (353).

The communication processor (320) can receive a baseband signal transmitted by the transceiver (350) and decode the received signal. The communication processor (330) can determine that the search for the base station (310) is successful when it confirms that the information obtained through decoding is information (e.g., MIB or SIB) required for connection with the base station (210). Alternatively, the communication processor (320) can determine that the search for the base station (310) is failed when it confirms that the decoding of the received signal fails or that the information obtained through decoding is not information (e.g., MIB or SIB) required for connection with the base station (310).

However, the frequency of the signal broadcast by the base station (310) and the frequency of the signal used by the transceiver (350) may not match. For example, depending on the movement of the electronic device (300), the frequency of the signal broadcast by the base station (310) may change due to the Doppler effect, and due to the aging of the base station (310), the frequency of the signal broadcast by the base station (310) may be different from a pre-specified frequency. The electronic device (300) may support AFC (automatic frequency control) in consideration of the above phenomenon. AFC may mean a function of changing the frequency (e.g., 2.6 GHz) of a signal generated by the transceiver (350) within a pre-specified range (e.g., 5 ppm; 2.599974 GHz to 2.6000026 GHz). The communication processor (320) can change the frequency of a reference signal used in an operation of changing a signal broadcast by the base station (310) into a baseband signal through the antenna (360) while checking the frequency of the signal broadcast by the base station (310). For example, the communication processor (320) can change the signal broadcast by the base station (310) into a baseband signal by using a reference signal having a frequency changed within a specified range, and if decoding is successful, can determine the changed frequency as the frequency of the signal broadcast by the base station (310).

The XO (340) may include a crystal element that vibrates at a reference frequency based on the control of the communication processor (320). The frequency band of the vibration of the crystal element may vary depending on the temperature. The XO (340) may transmit a temperature value measured by an internal temperature sensor to the communication processor (320). The communication processor (320) may transmit a signal for controlling a separate element for compensating for the frequency that varies depending on the temperature to the XO (340). The XO (340) may compensate for the frequency band of the signal by using an element having different impedance depending on the temperature based on the control of the communication processor (330). The clock generator (330) may generate a reference clock so that a signal used by the transceiver (350) has a designated frequency band. The transceiver (350) can generate a signal of a required frequency band (e.g., a reference frequency) based on a clock generated on a clock generator (330) and convert a signal received through an antenna (360) into a baseband signal.

Figure 4 is a graph showing the initial process error according to a comparative example.

The crystal oscillator (XO) may require initial error calibration to be used as a source of accurate clock. In addition, the frequency generated by the crystal oscillator (XO) may vary depending on the ambient temperature. The relationship between the frequency error generated in the crystal oscillator (XO) and temperature can be called the FT Curve and can be expressed by mathematical equation 1.

[Mathematical formula 1]

f(t)=C3(t-t0)^3+C2(t-t0)^2+C1(t-t0)+C0

The coefficients of the FT function (C0, C1, C2, C3) can change as the electronic device continues to perform calibration through communication with the base station. The calibration can be performed at the process stage, and the coefficients can be optimized for the temperature of the sample (e.g., crystal) during this process. The crystal oscillator (XO) can find the load capacitance that can achieve the optimal resonance by adjusting the values for the coefficients. In addition, the coefficients of the optimized FT function calculated at a specific temperature (e.g., room temperature) can be applied as reference values during calibration.

However, two situations may occur during the calibration process of the crystal oscillator (XO) according to the comparative example. The first situation is that the coefficient values of the FT function in the active state of the clock generator and the coefficient values of the FT function in the sleep state when the clock generator is inactive may be different from each other. The sleep state may be a different state from the active state. The sleep state may include, for example, a situation in which the electronic device (101) is in airplane mode. If the coefficient values in the sleep state are different from the coefficient values in the active state, the crystal oscillator (XO) may have difficulty in generating an optimized load capacitance. If the crystal oscillator (XO) does not have an optimized load capacitance, an error may occur when generating a frequency. The second situation is that when the clock generator is in a sleep state, the coefficients of the FT function cannot be calibrated, so it is difficult to update the coefficients of the optimal FT function according to the temperature change. When the ambient temperature changes while the clock generator is in a sleep state, the clock generator may not be able to update the coefficients. If the coefficients cannot be updated when the ambient temperature changes, the crystal oscillator (XO) may generate an error when generating the frequency.

If an error occurs in the frequency generation of the crystal oscillator (XO) when the electronic device is in a sleep state, problems may occur in the electronic device's system. For example, the electronic device may not be able to perform normal wake-up operations due to an error in the normal clock. Or, in the case of a motor, if a call comes in while in a sleep state, it may not vibrate due to a malfunction. Or, in the case of Wi-Fi, a periodic search operation is performed to find an AP when connecting, but normal searching may be difficult due to an error in the clock.

An electronic device according to various embodiments of the present document can provide a method for maintaining an optimized load capacitance in a sleep state and optimizing the coefficients of an FT function according to temperature changes.

FIG. 5 illustrates a first embodiment in which the coefficients of the FT function can be updated according to temperature when the electronic device is in a sleep state.

A processor (e.g., processor (120) of FIG. 1) can perform calibration of coefficients of an FT function based on the electronic device (e.g., electronic device (101) of FIG. 1) entering a sleep mode. Although described in this document as being performed by the processor (120), it may also be performed by at least one component (e.g., communication processor) of the electronic device (e.g., electronic device (101) of FIG. 1). The processor (120) can determine calibrated coefficient values and reduce a frequency error occurring on an XO by using the coefficient values determined in the sleep mode.

However, even if the coefficient values to be used in the sleep mode are determined, it may be difficult to update the coefficient values of the FT function. In FIGS. 5 and 6, a method for updating the coefficients of the FT function according to temperature even when the electronic device (100) is in the sleep mode will be described.

In FIG. 5, the processor (120) can store a table in which coefficient values according to temperature change are described for each model before mass production in a memory (e.g., memory (130) of FIG. 1). The processor (120) can fix a trim value at room temperature (approximately 25 degrees) and perform calibration while changing the temperature. The trim value may be a value for determining the period of a clock signal. Accordingly, the processor (120) can control the output so that the period of the clock signal on the crystal oscillator (XO) becomes constant by using the trim value. The processor (120) can perform calibration while changing the temperature to determine coefficients (e.g., C0, C1, C2, C3) for reducing the frequency error of the crystal oscillator (XO). The coefficients (e.g., C0, C1, C2, C3) may mean coefficients of an FT function, and the FT function has been described by mathematical expression 1.

f(t)=C3(t-t0)^3+C2(t-t0)^2+C1(t-t0)+C0

The coefficients (C0, C1, C2, C3) of the FT function may change as the electronic device continues to perform calibration through communication with the base station. The calibration may be performed at the process stage, and the coefficients optimized for the temperature of the sample (e.g., crystal) may be determined during this process. The processor (120) may find the load capacitance for which the crystal oscillator (XO) can optimally resonate while adjusting the coefficient values of the FT function. In addition, the optimized coefficients calculated at room temperature may be applied as reference values during calibration.

For example, the optimal coefficient value obtained through the calibration of the crystal oscillator (XO) at 30 degrees can be expressed as SLEEP_C0_30. SLEEP means sleep state, C0 means the type of coefficient, and 30 can mean the temperature in Celsius. This can be confirmed through the table described in Figure 510.

In Figure 520, the processor (120) can determine an offset value to be applied when the temperature of the electronic device (101) is 30 degrees. The offset value can mean the difference between the value of SLEEP_C0_30 and the SLEEP_C0 value obtained at room temperature. In this way, the offset value can be determined for each temperature by comparing the coefficient value of a specific temperature (e.g., 30 degrees) and the room temperature. The processor (120) can store the determined offset value for each temperature on the memory (130).

According to section 525, the processor (120) can determine the offset value (C0_offset_30) by calculating the difference between the value of SLEEP_C0_30 and the SLEEP_C0 value obtained at room temperature. In Figure 5, it is explained assuming a situation where the temperature of the electronic device (101) is 30 degrees, but this is only an example, and the temperature of the electronic device (101) may vary depending on the situation.

According to one embodiment, the processor (120) may determine coefficients of an FT function for reducing a frequency error occurring on a crystal oscillator by performing calibration at a first temperature during a product test process, and may determine coefficients of an FT function for reducing a frequency error occurring on a crystal oscillator by performing calibration at a second temperature different from the first temperature. The processor (120) may compare coefficients of an FT function at the first temperature and coefficients of an FT function at the second temperature to determine a difference value as an offset, store the determined offset value on the memory (130), and determine coefficients of an FT function for reducing a frequency error occurring on a crystal oscillator when the electronic device (101) is in a sleep mode based on a trim value when the electronic device (101) is in a sleep mode, an external temperature, and the determined offset value. Reducing the error here could mean making the value of the FT function approach zero. Or reducing the error could mean making the absolute value of the value of the FT function smaller.

According to one embodiment, the processor (120) may determine an offset value at the second temperature stored in the memory (130) based on the external temperature of the electronic device being the second temperature, add the offset value at the second temperature and the coefficient of the FT function of the first temperature to determine a coefficient of the FT function at the second temperature, and apply the coefficient of the FT function at the second temperature, which is determined based on the temperature of the electronic device (101) being the second temperature and the electronic device being in a sleep state, to the crystal oscillator.

According to one embodiment, the processor (120) may perform calibration at a third temperature different from the second temperature to determine coefficients of an FT function for reducing a frequency error occurring on a crystal oscillator, compare the coefficients of the FT function at the first temperature with the coefficients of the FT function at the third temperature to determine an offset, and store the determined offset value on the memory (130). The processor (120) may apply the coefficients of the FT function at the third temperature, which are determined based on the temperature of the electronic device (101) being the third temperature and in a sleep state, to the crystal oscillator.

FIG. 6 illustrates a second embodiment in which the coefficients of the FT function can be updated according to temperature when the electronic device is in a sleep state.

A processor (e.g., processor (120) of FIG. 1) may store, in a memory (e.g., memory (130) of FIG. 1), how coefficients of an FT function change according to temperature change during calibration while a clock generator is active. The processor (120) may determine a change value of the coefficients in a sleep state based on the change value of the stored coefficients of the FT function. According to a comparative example, an electronic device may update the coefficients of the FT function according to the temperature while the clock generator is active. However, the coefficients of the FT function may be difficult to update in the sleep state.

The processor (120) can update the coefficient change value when the clock generator is in a sleep state based on the coefficient change value of the FT function according to the temperature change when the clock generator is in an active state.

In Figure 610, the processor (120) can update the coefficients of the FT function according to temperature change.

Hereinafter, in Fig. 620, the processor (120) can determine an offset value for each coefficient of the FT function. This has been described in Fig. 5. For example, an optimal coefficient value obtained through calibration of a crystal oscillator (XO) at 30 degrees can be expressed as SLEEP_C0_30. SLEEP means a sleep state, C0 means a type of coefficient, and 30 means a temperature in degrees Celsius. The processor (120) can determine an offset value to be applied when the temperature of the electronic device (101) is 30 degrees. The offset value can mean a difference between the value of SLEEP_C0_30 and the SLEEP_C0 value obtained at room temperature. In this way, the offset value can be determined for each temperature by comparing the coefficient values of a specific temperature (e.g., 30 degrees) and room temperature. The processor (120) can store the determined offset values for each temperature on the memory (130).

According to Figure 620, for example, when the temperature is X degrees, the offset value may be C0_offset_X. This may be determined as a value obtained by subtracting Active_C0 from Active_C0_X. Active may indicate that the electronic device (101) or the clock generator is activated. C0 may indicate a coefficient of an FT function. X may indicate a temperature, and if no indication is provided, it may mean room temperature. In this manner, the processor (120) may determine an offset value for each temperature and coefficient.

In Figure 630, the processor (120) can use the coefficient value and offset value of the FT function determined when the electronic device (101) or the clock generator is in the sleep state based on the active state. The processor (120) can use the coefficient value and offset value of the FT function determined when the active state to determine the coefficient value and offset value of the FT function in the sleep state.

According to Figure 632, for example, when the temperature is X degrees, the offset value may be C0_offset_X. This may be determined as a value obtained by subtracting Sleep_C0 from Sleep_C0_X. Sleep may indicate that the electronic device (101) or the clock generator is in a sleep state. C0 may indicate a coefficient of an FT function. X may indicate a temperature, and if there is no indication, it may mean room temperature. Sleep_C0 may indicate a coefficient value of an FT function at room temperature. Sleep_C0_X may indicate a coefficient value of an FT function when the temperature is X. In this manner, the processor (120) may determine an offset value for each temperature and coefficient.

According to Figure 634, for example, when the temperature is Y degrees, the offset value may be C0_offset_Y. This may be determined as a value obtained by subtracting Sleep_C0 from Sleep_C0_Y. Sleep may indicate that the electronic device (101) or the clock generator is in a sleep state. C0 may indicate a coefficient of an FT function. Y may indicate a temperature, and if there is no indication, it may mean room temperature. In this way, the processor (120) may determine an offset value for each temperature and coefficient. Y may indicate a different temperature than X.

According to one embodiment, the processor (120) may measure a first temperature (e.g., X degrees) at which the coefficient value of the FT function changes beyond a specified first level based on the coefficient value of the FT function at room temperature. The processor (120) may apply the coefficient value of the FT function measured when the electronic device is in an active state as the coefficient value of the FT function in the sleep state based on the external temperature of the electronic device (101) being measured as the first temperature when the electronic device is in a sleep state. This is as described in Figure 632.

According to one embodiment, the processor (120) may measure a first temperature (e.g., Y degrees) at which the coefficient value of the FT function changes to exceed a specified second level based on the coefficient value of the FT function at room temperature. The processor (120) may apply the coefficient value of the FT function measured when the electronic device (101) is in an active state, based on the external temperature of the electronic device (101) being measured as the second temperature when the electronic device is in a sleep state, as the coefficient value of the FT function in the sleep state. This is as described in Figure 634. The first temperature and the second temperature are not preset values and may mean temperatures at which the coefficient of the FT function changes. The temperature at which the coefficient of the FT function changes to exceed the first level (e.g., 20% compared to room temperature) may be determined as the first temperature. The temperature at which the coefficient of the FT function changes by more than a second level (e.g., 40% relative to room temperature) can be determined as the second temperature. The first level and the second level are only examples and may vary depending on the settings.

FIG. 7 is a flowchart illustrating a method for controlling a crystal oscillator (XO) of an electronic device according to one embodiment.

The operations described through FIG. 7 can be implemented based on instructions that can be stored in a computer recording medium or memory (e.g., memory (130) of FIG. 1). The illustrated method can be executed by an electronic device (e.g., electronic device (101) of FIG. 1) described above through FIGS. 1 to 6, and the technical features described above will be omitted below. The order of each operation of FIG. 7 can be changed, some operations can be omitted, and some operations can be performed simultaneously.

In operation 710, a processor (e.g., processor (120) of FIG. 1) may determine a trim value for controlling a crystal oscillator (XO) to oscillate at a constant frequency in response to a load capacitance of a clock generation circuit while the electronic device (101) is in a sleep mode. The trim value is a value related to the characteristics of a sample, and whether the XO has an optimal load capacitance may be determined based on the trim value.

The electronic device (101) may further include an oscillator configured to output an oscillator clock signal whose period is determined according to a trim value, and a clock counter configured to count the oscillator clock signal for a reference time. The processor (120) may decrease the count value by gradually increasing the trim value when the count value is greater than a target count value, and may increase the count value by gradually decreasing the trim value when the count value is less than or equal to the target count value. The oscillator may output the oscillator clock signal having a shorter period as the input trim value decreases.

According to one embodiment, when the count value increases and exceeds the target count value, the processor (120) may determine a trim value corresponding to the count value exceeding the target count value as the final trim value in the sleep state. When the count value decreases and falls below the target count value, the processor (120) may determine a trim value corresponding to the count value below the target count value as the final trim value in the sleep state.

The processor (120) can store the determined trim value in the memory (130). The determined trim value may mean a value that controls the crystal oscillator (XO) to vibrate at a constant frequency in a sleep mode rather than an active state. The oscillator can output an oscillator clock signal having a period determined according to the stored final trim value.

At operation 720, the processor (120) may apply a trim value determined based on the state of the electronic device transitioning from an active mode to a sleep mode.

In operation 730, the processor (120) can store coefficient values of an FT function to be applied on a crystal oscillator in response to a temperature change in the memory (130).

According to one embodiment, the processor (120) may determine coefficients of an FT function between frequency and temperature to reduce frequency errors occurring on a crystal oscillator by performing calibration at a first temperature during a product test process, and may determine coefficients of an FT function to reduce frequency errors occurring on a crystal oscillator by performing calibration at a second temperature different from the first temperature.

The processor (120) can compare the coefficient of the FT function of the first temperature with the coefficient of the FT function of the second temperature to determine an offset, and store the determined offset value on the memory (130). The processor (120) can determine the coefficient of the FT function for reducing a frequency error occurring on a crystal oscillator when the electronic device is in a sleep mode based on the trim value, the external temperature, and the determined offset value when the electronic device is in a sleep mode.

At operation 740, the processor (120) may apply the coefficient values of the FT function determined based on the state of the clock generator switching from active mode to sleep mode.

The processor (120) can determine a coefficient that makes the value of an FT function, in which the frequency error of a crystal oscillator is described along the y-axis and the temperature is described along the x-axis, become 0 in order to reduce the frequency error. The processor (120) can reduce the frequency error by applying a coefficient that makes the function value of an FT function, in which the frequency error is described along the y-axis and the temperature is described along the x-axis, become 0.

According to one embodiment, the processor (120) may perform calibration according to a temperature change in the electronic device (101) in an active state, measure a change in a coefficient of an FT function according to a temperature change, measure a first temperature at which a coefficient value of an FT function changes beyond a specified first level based on a coefficient value of the FT function at room temperature, and store the measured first temperature in the memory (130). The processor (120) may determine whether the electronic device (101) is in a sleep state and whether an external temperature of the electronic device (101) is measured as a first temperature. Based on the fact that the electronic device (101) is in a sleep state and the external temperature of the electronic device (101) is measured as the first temperature, the processor (120) may apply a coefficient value of the FT function measured when the electronic device (101) is in an active state as a coefficient value of the FT function in the sleep state.

According to one embodiment, the processor (120) may perform calibration according to a temperature change in the electronic device (101) in an active state, measure a change in a coefficient of an FT function according to a temperature change, measure a second temperature at which a coefficient value of an FT function changes beyond a designated second level based on a coefficient value of the FT function at room temperature, and store the measured second temperature in the memory (130). The processor (120) may determine whether the electronic device (101) is in a sleep state and whether an external temperature of the electronic device (101) is measured as a second temperature. Based on the fact that the electronic device (101) is in a sleep state and the external temperature of the electronic device (101) is measured as the second temperature, the processor (120) may apply a coefficient value of the FT function measured when the electronic device (101) is in an active state as a coefficient value of the FT function in the sleep state.

According to one embodiment, the processor (120) determines coefficients of an FT function between frequency and temperature to reduce a frequency error occurring on a crystal oscillator by performing calibration at a first temperature during a product test process, determines coefficients of an FT function to reduce a frequency error occurring on a crystal oscillator by performing calibration at a second temperature different from the first temperature, determines an offset by comparing the coefficients of the FT function at the first temperature and the coefficients of the FT function at the second temperature, stores the determined offset value in a memory, and determines a coefficient that makes the value of the FT function between frequency error and temperature 0 based on the external temperature and the determined offset value when the clock generator is in a sleep mode.

According to one embodiment, the processor (120) checks an offset value at a second temperature stored in a memory based on the external temperature of the electronic device being the second temperature, adds the offset value at the second temperature and a coefficient of the FT function of the first temperature to determine a coefficient of the FT function at the second temperature, and uses the coefficient of the FT function at the second temperature determined based on the temperature of the electronic device being the second temperature and the clock generator being in a sleep state to make the value of the FT function between the frequency error and the temperature become 0.

According to one embodiment, the processor (120) determines coefficients of an FT function for reducing a frequency error occurring in a crystal oscillator by performing calibration at a third temperature different from a second temperature, compares the coefficients of the FT function at the first temperature with the coefficients of the FT function at the third temperature to determine an offset, stores the determined offset value in a memory, and uses the coefficients of the FT function at the third temperature determined based on the temperature of the electronic device being the third temperature and the clock generator being in a sleep state to make the value of the FT function between the frequency error and the temperature 0.

FIG. 8 is a flowchart illustrating a method for controlling a crystal oscillator (XO) of an electronic device according to one embodiment.

The operations described through FIG. 8 may be implemented based on instructions that may be stored in a computer recording medium or memory (e.g., memory (130) of FIG. 1). The illustrated method (800) may be executed by an electronic device (e.g., electronic device (101) of FIG. 1) described above through FIGS. 1 to 6, and the technical features described above will be omitted below. The order of each operation of FIG. 7 may be changed, some operations may be omitted, and some operations may be performed simultaneously.

At operation 810, a processor (e.g., processor (120) of FIG. 1) may determine whether a clock generator is in a sleep state. The sleep state may be a different state from an active state. The sleep state may include, for example, a situation in which the electronic device (101) is in airplane mode.

At operation 812 (operation 810-yes), the processor (120) may determine a trim value to apply when in a sleep state based on whether the state of the electronic device (101) is in a sleep state.

The processor (120) can determine a trim value that controls the crystal oscillator (XO) to vibrate at a constant frequency in response to the load capacitance of the clock generation circuit while the electronic device (101) is in sleep mode.

The electronic device (101) may further include an oscillator configured to output an oscillator clock signal whose period is determined according to a trim value, and a clock counter configured to count the oscillator clock signal for a reference time. The processor (120) may decrease the count value by gradually increasing the trim value when the count value is greater than a target count value, and may increase the count value by gradually decreasing the trim value when the count value is less than or equal to the target count value. The oscillator may output an oscillator clock signal having a shorter period as an input trim value decreases.

According to one embodiment, when the count value increases and exceeds the target count value, the processor (120) may determine a trim value corresponding to the count value exceeding the target count value as the final trim value in the sleep state. When the count value decreases and falls below the target count value, the processor (120) may determine a trim value corresponding to the count value below the target count value as the final trim value in the sleep state.

In operation 814, the processor (120) may check the temperature of the electronic device (101) when in a sleep state and update the coefficients of the FT function.

The processor (120) can determine the coefficients of the FT function to be applied when the electronic device (101) is in a sleep state. The FT function can represent the relationship between the frequency error occurring in the crystal oscillator (XO) and the temperature.

In a subsequent operation 820, the processor (120) may apply coefficients of the compensated FT function to the crystal oscillator (XO) so that the crystal oscillator (XO) can oscillate at a constant frequency.

At operation 816 (operation 810-no), the processor (120) may determine the trim values to apply and the coefficients of the calibrated FT function when the electronic device (101) is in an active state based on the state not being in a sleep state.

In a subsequent operation 820, the processor (120) may apply coefficients of the compensated FT function to the crystal oscillator (XO) so that the crystal oscillator (XO) can oscillate at a constant frequency.

An electronic device may include a processor, a crystal oscillator (XO) that generates a reference clock for generating a signal having a reference frequency, and a memory. The processor may determine a trim value so that the clock generator can constantly generate a frequency in a sleep mode, apply the determined trim value based on the clock generator entering the sleep mode, perform calibration while the clock generator is in the sleep mode, determine a control coefficient that makes a frequency error of the crystal oscillator less than or equal to a threshold value, store the determined control coefficient value in the memory, and change the control coefficient to the control coefficient value determined in the sleep mode based on the state of the clock generator switching from an active mode to a sleep mode.

According to one embodiment, the processor determines coefficients of an FT function between frequency and temperature during a product test process to reduce a frequency error occurring on a crystal oscillator by performing calibration at a first temperature, determines coefficients of an FT function to reduce a frequency error occurring on the crystal oscillator by performing calibration at a second temperature different from the first temperature, determines an offset by comparing the coefficients of the FT function at the first temperature and the coefficients of the FT function at the second temperature, stores the determined offset value in a memory, and determines a coefficient that makes a frequency error value described on the y-axis and a temperature described on the x-axis become 0 based on an external temperature and the determined offset value when the clock generator is in a sleep mode, and changes the coefficients of the FT function to the determined values.

According to one embodiment, the processor determines an offset value at a second temperature stored in a memory based on the external temperature of the electronic device being the second temperature, adds the offset value at the second temperature and a coefficient of the FT function at the first temperature to determine a coefficient of the FT function at the second temperature, and uses the coefficient of the FT function at the second temperature determined based on the temperature of the electronic device being the second temperature and the clock generator being in a sleep state to make the value of the FT function between the frequency error and the temperature become 0.

According to one embodiment, the processor determines coefficients of an FT function for reducing a frequency error occurring in a crystal oscillator by performing calibration at a third temperature different from a second temperature, compares the coefficients of the FT function at the first temperature with the coefficients of the FT function at the third temperature to determine an offset, stores the determined offset value in a memory, and uses the coefficients of the FT function at the third temperature determined based on the temperature of the electronic device being the third temperature and the clock generator being in a sleep state to make the frequency error and the value of the FT function between the temperatures 0.

According to one embodiment, the processor performs calibration according to temperature change when the clock generator is in an active state, measures a change in a coefficient of an FT function according to the temperature change, measures a first temperature at which a coefficient value of the FT function changes by exceeding a first level specified based on a coefficient value of the FT function at room temperature and stores the measured first temperature in a memory, and uses the coefficient value of the FT function measured when the clock generator is in an active state based on the external temperature of the electronic device being measured as the first temperature when the clock generator is in a sleep state to make the value of the FT function between the frequency error and the temperature become 0.

According to one embodiment, the processor measures a second temperature at which a coefficient value of the FT function changes beyond a designated second level based on a coefficient value of the FT function at room temperature and stores the measured second temperature in a memory, and when the clock generator is in an active state based on an external temperature of the electronic device measured as the second temperature in a sleep state, the processor can reduce a frequency error occurring in a crystal oscillator (XO) by using the measured coefficient value of the FT function.

According to one embodiment, the electronic device further includes an oscillator configured to output an oscillator clock signal, a period of which is determined according to a trim value, and a clock counter configured to count the oscillator clock signal for a reference time, wherein the processor can decrease the count value by gradually increasing the trim value when the count value is greater than a target count value, and can increase the count value by gradually decreasing the trim value when the count value is less than or equal to the target count value.

According to one embodiment, the oscillator can output an oscillator clock signal having a shorter period as the input trim value becomes smaller.

According to one embodiment, when the count value increases and the count value exceeds a target count value, the processor may determine a trim value corresponding to the count value exceeding the target count value as a final trim value in the sleep state, and when the count value decreases and is less than the target count value, the processor may determine a trim value corresponding to the count value less than the target count value as the final trim value in the sleep state.

According to one embodiment, the processor can store the determined final trim value in memory, and the oscillator can output an oscillator clock signal having a period determined according to the stored final trim value.

A method for controlling a crystal oscillator (XO) of an electronic device may include an operation of performing calibration while a clock generator is in a sleep mode, an operation of determining a control coefficient that causes a frequency error of the crystal oscillator to be expressed along the y-axis and become less than or equal to a threshold value, an operation of storing the determined control coefficient value in a memory, and an operation of changing the control coefficient to the determined control coefficient value while in the sleep mode based on a state of the clock generator being switched from an active mode to a sleep mode.

Claims (15)

In electronic devices, processor; A crystal oscillator (XO) that generates a reference clock for generating a signal having a reference frequency; and Contains memory The above processor Determine the trim value so that the clock generator can generate a constant frequency while in sleep mode. Applying a trim value determined based on the above clock generator entering a sleep mode, Calibration is performed while the clock generator is in sleep mode. Determine the control coefficient that makes the frequency error of the above crystal oscillator be below the threshold value, Store the determined control coefficient values in the above memory, An electronic device that changes a control coefficient to a control coefficient value determined in the sleep mode based on the state of the clock generator switching from active mode to sleep mode. In paragraph 1, The above processor During the product testing process, calibration is performed at the first temperature to determine the coefficients of the FT function between frequency and temperature to reduce the frequency error occurring on the crystal oscillator. The coefficients of the FT function are determined to reduce the frequency error occurring on the crystal oscillator by performing calibration at a second temperature different from the first temperature. The offset is determined by comparing the coefficient of the FT function of the first temperature and the coefficient of the FT function of the second temperature, Store the determined offset value in the above memory, An electronic device that determines a coefficient that makes the value of an FT function, in which a frequency error value is written along the y-axis and a temperature is written along the x-axis, become 0 based on an external temperature and a determined offset value when the above clock generator is in a sleep mode, and changes the coefficient of the FT function to the determined value. In the second paragraph, The above processor Based on the external temperature of the electronic device being the second temperature, the offset value at the second temperature stored in the memory is checked, The coefficient of the FT function at the second temperature is determined by adding the offset value at the second temperature and the coefficient of the FT function at the first temperature. An electronic device that uses the coefficients of the FT function at the second temperature determined based on the temperature of the electronic device being the second temperature and the clock generator being in a sleep state to make the value of the FT function between the frequency error and the temperature zero. In the second paragraph, The above processor The coefficients of the FT function are determined to reduce the frequency error occurring on the crystal oscillator by performing calibration at a third temperature different from the above second temperature. The offset is determined by comparing the coefficient of the FT function of the first temperature and the coefficient of the FT function of the third temperature, Store the determined offset value in the above memory, An electronic device that uses the coefficients of the FT function at the third temperature determined based on the temperature of the electronic device being the third temperature and the clock generator being in a sleep state to make the value of the FT function between the frequency error and the temperature zero. In paragraph 1, The above processor When the above clock generator is active, calibration is performed according to temperature changes. Measure the change in the coefficients of the FT function with temperature change, A first temperature at which the coefficient value of the FT function changes beyond a specified first level based on the coefficient value of the FT function at room temperature is measured and stored in the memory, An electronic device that uses the coefficient values of the FT function measured when the clock generator is in an active state based on the external temperature of the electronic device being measured as the first temperature when the clock generator is in a sleep state to make the value of the FT function between the frequency error and the temperature 0. In paragraph 5, The above processor A second temperature at which the coefficient value of the FT function changes beyond a specified second level based on the coefficient value of the FT function at room temperature is measured and stored in the memory. An electronic device that reduces a frequency error occurring on the crystal oscillator (XO) by using the coefficient values of the FT function measured when the clock generator is in an active state based on the external temperature of the electronic device being measured as the second temperature when the clock generator is in a sleep state. In paragraph 1, The above electronic device An oscillator configured to output an oscillator clock signal whose period is determined by a trim value; and Further comprising a clock counter configured to count the above oscillator clock signal for a reference time, The above processor If the count value is greater than the target count value, the count value is decreased by gradually increasing the trim value, An electronic device that increases the count value by gradually decreasing the trim value when the count value is less than or equal to the target count value. In Article 7, The above oscillator An electronic device that outputs an oscillator clock signal having a shorter period as the input trim value becomes smaller. In Article 7, The above processor As the count value increases, if the count value exceeds the target count value, a trim value corresponding to the count value exceeding the target count value is determined as the final trim value in the sleep state, An electronic device that determines a trim value corresponding to a count value less than the target count value as the final trim value in a sleep state when the count value decreases and the count value is less than the target count value. In Article 9, The above processor Store the final trim value determined above in the memory, The above oscillator, An electronic device that outputs the oscillator clock signal having a period determined based on the stored final trim value. In a method for controlling a crystal oscillator (XO) of an electronic device, An operation to perform calibration while the clock generator is in sleep mode; An operation for determining a control coefficient that makes the frequency error of the above crystal oscillator less than a threshold value; An operation of storing the determined control coefficient values in memory; and A method including an operation of changing a coefficient of an FT function to a control coefficient value determined in the sleep mode based on the state of the clock generator switching from an active mode to a sleep mode. In Article 11, During the product testing process, an operation to determine the coefficients of the FT function between frequency and temperature to reduce the frequency error occurring on the crystal oscillator by performing calibration at the first temperature; An operation of determining coefficients of an FT function to reduce frequency errors occurring on a crystal oscillator by performing calibration at a second temperature different from the first temperature; An operation of determining an offset by comparing the coefficient of the FT function of the first temperature and the coefficient of the FT function of the second temperature; An operation of storing a determined offset value in the memory; and A method further comprising: determining a coefficient that makes the value of an FT function between a frequency error and a temperature become 0 based on an external temperature and a determined offset value when the clock generator is in a sleep mode; and changing the coefficient of the FT function to the determined value. In Article 12, An operation of determining coefficients of an FT function for reducing a frequency error occurring on a crystal oscillator when the electronic device is in a sleep mode based on a trim value, an external temperature, and a determined offset value when the electronic device is in a sleep mode. An operation of checking an offset value at the second temperature stored in the memory based on the external temperature of the electronic device being the second temperature; An operation of determining a coefficient of an FT function at the second temperature by adding an offset value at the second temperature and a coefficient of an FT function at the first temperature; and A method further comprising the action of making the value of the FT function between the frequency error and the temperature become 0 by using the coefficient of the FT function at the second temperature determined based on the temperature of the electronic device being the second temperature and the clock generator being in a sleep state. In Article 12, An operation of determining coefficients of an FT function for reducing a frequency error occurring on a crystal oscillator when the electronic device is in a sleep mode based on a trim value, an external temperature, and a determined offset value when the electronic device is in a sleep mode. An operation of determining the coefficients of an FT function to reduce frequency errors occurring on a crystal oscillator by performing calibration at a third temperature different from the second temperature; An operation of comparing the coefficient of the FT function of the first temperature and the coefficient of the FT function of the third temperature to determine an offset, and storing the determined offset value in the memory; and A method further comprising the action of making the value of the FT function between the frequency error and the temperature become 0 by using the coefficient of the FT function at the third temperature determined based on the temperature of the electronic device being the third temperature and the clock generator being in a sleep state. In Article 11, An operation in which the above clock generator performs calibration according to temperature changes while in an active state; An operation that measures the change in the coefficients of an FT function with respect to temperature change; An operation of measuring a first temperature at which the coefficient value of the FT function changes beyond a specified first level based on the coefficient value of the FT function at room temperature and storing the measured temperature in the memory; and A method further comprising: using the coefficient values of the FT function measured when the electronic device is in an active state based on the external temperature of the electronic device being measured as the first temperature when the clock generator is in a sleep state to make the value of the FT function between the frequency error and the temperature 0.

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