A crystal oscillator control circuit, a crystal oscillator start-up control method and an electronic device

Abstract

The embodiment of the present invention provides a crystal oscillator control circuit, a crystal oscillator oscillation control method and an electronic device, which are used to realize fast oscillation of the crystal oscillator and low power consumption during the oscillation process. The circuit includes a crystal oscillator driving module, a signal processing module, a capacitor array control module, a capacitor array module and a crystal oscillator connected in sequence, the crystal oscillator driving module is also connected to the crystal oscillator, and the crystal oscillator driving module is used to provide driving energy for the crystal oscillator; the signal processing module is used to perform preset processing on the received first clock signal to obtain a second clock signal, and output the second clock signal to the capacitor array control module; the capacitor array control module is used to generate a first control signal under the control of the second clock signal, and output the first control signal to the capacitor array module; the capacitor array module is used to set the initial capacitance value of the crystal oscillator oscillation under the control of the first control signal, and adjust the oscillation waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator.

Description

Technical Field

[0001] The present invention relates to the field of integrated circuit design, and in particular to a crystal oscillator control circuit, a crystal oscillator oscillation control method and electronic equipment. Background Art

[0002] With the development of electronic technology, more and more electronic devices have become people's personal belongings, such as smart bracelets, watches, Bluetooth headsets, etc. These devices are usually limited by size, have low battery capacity, and have strict requirements on chip power consumption. In order to save power consumption, the device is usually in standby mode and is activated only when it needs to be connected to a mobile phone. As a crystal oscillator that provides a clock to the system, its start-up time and power consumption are particularly important. The longer the start-up time of the crystal oscillator, the more energy it consumes, and the higher the power consumption in the whole machine. For example, in the Bluetooth Low Energy (BLE) protocol, the transmission time of a data packet may be only a few hundred microseconds, while the start-up time of a crystal oscillator can usually reach milliseconds, which is longer than the data transmission time. A long start-up time of the crystal oscillator will not only take up valuable time resources and affect transmission efficiency, but also increase the power consumption of the entire transmission process.

[0003] In order to shorten the crystal oscillator start-up time, the prior art increases the start-up current to improve the transconductance of the start-up circuit, thereby speeding up the crystal oscillator start-up time. Figure 1 As shown in the figure, dual drive currents are used for oscillation start-up, and a drive current is turned off after the crystal oscillator starts to save power to achieve fast oscillation start-up. Although this method achieves fast oscillation start-up and low power consumption when the crystal oscillator is working, it is achieved at the expense of power consumption during oscillation start-up. In addition, due to the sudden change of the drive current, there is a great disturbance to the oscillation waveform, and the crystal oscillator needs to be stabilized again. It is not applicable to some systems with strict requirements.

[0004] In summary, the crystal oscillator starting method in the prior art has the problem of being unable to take into account both fast starting and low power consumption at the same time. Summary of the invention

[0005] The embodiment of the present invention provides a crystal oscillator control circuit, a crystal oscillator start-up control method and an electronic device, which are used to realize fast start-up of the crystal oscillator and low power consumption during the start-up process.

[0006] In a first aspect, an embodiment of the present invention provides a crystal oscillator control circuit, comprising: a crystal oscillator drive module, a signal processing module, a capacitor array control module, a capacitor array module, and a crystal oscillator connected in sequence, wherein:

[0007] A crystal oscillator driving module, used for providing driving energy for the crystal oscillator and outputting a first clock signal generated by the crystal oscillator to the signal processing module;

[0008] A signal processing module, used for performing preset processing on the received first clock signal to obtain a second clock signal, and outputting the second clock signal to the capacitor array control module;

[0009] A capacitor array control module, used to generate a first control signal under the control of a second clock signal, and output the first control signal to the capacitor array module;

[0010] The capacitor array module is used to set the initial capacitance value of the crystal oscillator under the control of the first control signal, and adjust the crystal oscillator's starting waveform and oscillation frequency by changing the crystal oscillator's load capacitance value.

[0011] The crystal oscillator control circuit provided by the embodiment of the present invention is composed of five parts, namely, a crystal oscillator driving module, a crystal oscillator, a capacitor array module, a capacitor array control module and a signal processing module. Among them, the crystal oscillator driving module is connected to the crystal oscillator, used to provide driving energy for the crystal oscillator, and convert the sine wave of the crystal oscillation into a square wave, so that the crystal oscillator maintains a reliable piezoelectric oscillation characteristic and outputs a corresponding oscillation waveform; the signal processing module is used to perform preset processing on the received first clock signal to obtain a second clock signal, and output the second clock signal to the capacitor array control module; the capacitor array control module is used to generate a first control signal under the control of the second clock signal, and output the first control signal to the capacitor array module, so as to achieve rapid oscillation and smooth control of the crystal oscillator oscillation waveform; the capacitor array module is connected to the crystal oscillator, and is used to set the initial capacitance value of the crystal oscillator oscillation under the control of the first control signal sent by the capacitor array control module, and adjust the crystal oscillator oscillation waveform and oscillation frequency by changing the load capacitance value of the crystal oscillator. Compared with the prior art, the crystal oscillator can be quickly started while reducing the power consumption during the oscillation process by changing the capacitance value of the capacitor array module.

[0012] In a possible implementation, the capacitor array module adjusts the starting waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator, specifically for:

[0013] When the crystal oscillator waveform reaches the preset amplitude, the load capacitance of the crystal oscillator is controlled to reach the target capacitance value by increasing the set capacitance value each time, and the starting waveform and oscillation frequency of the crystal oscillator are adjusted.

[0014] The crystal oscillator control circuit provided in the embodiment of the present invention controls the load capacitance of the crystal oscillator to obtain the target capacitance value by increasing the set capacitance value each time when the crystal oscillator waveform reaches a preset amplitude, thereby reducing the impact on the oscillation waveform of the crystal oscillator and making the oscillation waveform of the crystal oscillator smoother and more stable when adjusting the capacitance.

[0015] In a possible implementation, the crystal oscillator is a single external high-frequency crystal oscillator or a single external low-frequency crystal oscillator, and the crystal oscillator drive module, the capacitor array module, the capacitor array control module and the signal processing module are all arranged inside the chip.

[0016] In a possible implementation, the capacitor array module includes: a plurality of capacitor components and a switch component connected between each capacitor component and a ground line, wherein each switch component is used to perform a switching action according to a first control signal sent by the capacitor array control module to control whether the capacitor component connected to each switch component is connected to the capacitor array module.

[0017] In a possible implementation, the capacitor array module is also used to adjust the starting waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator, wherein the manner of changing the load capacitance value of the crystal oscillator includes one or more of the following: thermometer coding and binary coding.

[0018] In a possible implementation manner, the capacitor array module is specifically used for:

[0019] A thermometer coding method is used for the capacitance component whose capacitance value change of the load capacitance of the crystal oscillator is greater than a preset threshold value;

[0020] A binary coding method is used for the capacitor component whose capacitance value change of the load capacitor of the crystal oscillator is less than or equal to the preset threshold.

[0021] In a possible implementation, the capacitor array control module includes: a digital comparator and a bidirectional counter connected in sequence, wherein:

[0022] A digital comparator, used to compare a first control signal output by the capacitor array control module with a second control signal corresponding to a target capacitance value, and output an adjustment signal for adjusting the first control signal;

[0023] The bidirectional counter is used to count the adjustment signal output by the digital comparator under the control of the second clock signal, and adjust the first control signal according to the counting result.

[0024] In a possible implementation, the preset processing of the signal processing module includes one or more of the following: frequency division processing and delay processing.

[0025] In a second aspect, an embodiment of the present invention provides an electronic device, comprising the crystal oscillator control circuit of any one of the first aspect of the embodiments of the present invention.

[0026] In a third aspect, an embodiment of the present invention provides a crystal oscillator start-up control method, which is used in the crystal oscillator control circuit described in any one of the first aspects of the embodiments of the present invention, and the method includes:

[0027] The crystal oscillator driving module drives the crystal oscillator to generate a first clock signal, and outputs the first clock signal to the signal processing module;

[0028] The signal processing module processes the preset clock signal to obtain a second clock signal, and outputs the second clock signal to the capacitor array control module;

[0029] The capacitor array control module generates a first control signal based on the second clock signal, and transmits the first control signal to the capacitor array module;

[0030] The capacitor array module sets the initial capacitance value of the crystal oscillator based on the control of the first control signal, and adjusts the crystal oscillator's starting waveform and oscillation frequency by changing the crystal oscillator's load capacitance value.

[0031] In a possible implementation, the capacitor array module adjusts the starting waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator, including:

[0032] When the crystal oscillator waveform reaches the preset amplitude, the load capacitance is controlled to reach the target capacitance value by increasing the set capacitance value each time, and the starting waveform and oscillation frequency of the crystal oscillator are adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, in which:

[0034] Figure 1 A schematic diagram of a waveform of a crystal oscillator starting oscillation provided by an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of the structure of a crystal oscillator control circuit provided by an embodiment of the present invention;

[0036] Figure 3 A schematic diagram of the structure of a crystal oscillator circuit provided in an embodiment of the present invention;

[0037] Figure 4 A circuit diagram of a crystal oscillator equivalent model provided by an embodiment of the present invention;

[0038] Figure 5 A schematic diagram of the relationship between the start-up time and load capacitance of a crystal oscillator provided in an embodiment of the present invention;

[0039] Figure 6 A schematic diagram of the structure of a capacitor array module provided by an embodiment of the present invention;

[0040] Figure 7 A schematic structural diagram of another capacitor array module provided by an embodiment of the present invention;

[0041] Figure 8 A schematic diagram of the structure of a capacitor array control module provided by an embodiment of the present invention;

[0042] Fig. 9 A schematic diagram of the structure of a signal processing module provided by an embodiment of the present invention;

[0043] Fig.10 A schematic diagram of the structure of a delay unit provided in an embodiment of the present invention;

[0044] Fig.11 A signal adjustment schematic diagram of a signal processing module provided by an embodiment of the present invention;

[0045] Fig.12 A schematic diagram of waveforms during the oscillation start-up process of a high-frequency crystal oscillator provided by an embodiment of the present invention;

[0046] Fig.13 A schematic diagram of waveforms during the start-up process of another high-frequency crystal oscillator provided by an embodiment of the present invention;

[0047] Fig.14 A schematic diagram of waveforms during the oscillation start-up process of a low-frequency crystal oscillator provided by an embodiment of the present invention;

[0048] Fig.15 A schematic flow chart of a crystal oscillator start-up control method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0050] Since the prior art cannot provide a stable and fast crystal oscillator starting method, an embodiment of the present invention provides a crystal oscillator control circuit to provide a stable and fast crystal oscillator starting method, thereby achieving fast crystal oscillator starting and low starting power consumption.

[0051] The solution provided by the embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0052] like Figure 2 As shown, an embodiment of the present invention provides a crystal oscillator control circuit, comprising: a crystal oscillator drive module 21, a signal processing module 22, a capacitor array control module 23, a capacitor array module 24 and a crystal oscillator 25 connected in sequence, the crystal oscillator drive module 21 is also connected to the crystal oscillator 25, wherein:

[0053] The crystal oscillator driving module 21 is used to provide driving energy for the crystal oscillator 25 and output the first clock signal (CLK_OSC) generated by the crystal oscillator 25 to the signal processing module 22;

[0054] The signal processing module 22 is used to perform preset processing on the received first clock signal (CLK_OSC) to obtain a second clock signal (CK_R), and output the second clock signal (CK_R) to the capacitor array control module 23;

[0055] The capacitor array control module 23 is used to generate a first control signal (CAP_CTL) under the control of the second clock signal (CK_R) output by the signal processing module 22 , and output the first control signal (CAP_CTL) to the capacitor array module 24 .

[0056] The capacitor array module 24 is used to set the initial capacitance of the crystal oscillator 25 under the control of the first control signal (CAP_CTL) sent by the capacitor array control module 23, and adjust the starting waveform and oscillation frequency of the crystal oscillator 25 by changing the load capacitance value of the crystal oscillator 25.

[0057] In a specific implementation, the capacitor array module adjusts the starting waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator. When the crystal oscillator waveform reaches a preset amplitude, the load capacitance of the crystal oscillator is controlled to reach a target capacitance value by increasing the set capacitance value each time, so as to adjust the starting waveform and oscillation frequency of the crystal oscillator. The preset amplitude can be set according to an empirical value, which is not limited in the embodiment of the present invention.

[0058] Among them, the initial capacitance can be flexibly set according to the actual scenario. For example, the initial capacitance can be 0, or it can be the minimum capacitance value or a multiple of the minimum capacitance value of the capacitor array module. The set capacitance value can be the minimum capacitance adjustment amount of the capacitor array module, or it can be a multiple of the minimum capacitance adjustment amount of the capacitor array module. The embodiment of the present invention does not limit this.

[0059] Of course, it should be noted that, in the process of increasing the set capacitance value each time to control the load capacitance of the crystal oscillator to reach the target capacitance value, the set capacitance value can be fixed, that is, the first control signal is specifically used to adjust the capacitance value of the capacitor array module starting with the initial capacitance, and the set capacitance value is uniformly increased at intervals to reach the target capacitance value; the set capacitance value can also be constantly changing, for example, when the adjustment starts, the set capacitance value is small, and as the adjustment time increases, the set capacitance value continues to increase. Of course, the set capacitance value can also change according to other rules or change randomly, and the embodiments of the present invention are not limited to this.

[0060] In one example, the first control signal (CAP_CTL) generated by the capacitor array control module can adjust the capacitance value of the capacitor array module starting from 0, and uniformly increase the capacitance value at intervals with the minimum capacitance adjustment value of the capacitor array module to reach the target capacitance value.

[0061] In specific implementation, after the circuit is enabled, the initial value of the capacitor array is set to 0 by the capacitor array control module 23, that is, CAP_CTL=0, and the circuit starts oscillating quickly in the minimum load capacitance mode; when the oscillation amplitude of the crystal oscillator 25 increases to a preset value, the crystal oscillator driving module outputs a first clock signal (CLK_OSC), and outputs a second clock signal (CK_R) after delay and frequency division processing by the signal processing module 22; the capacitor array control module 23 compares the first control signal (CAP_CTL) with the second control signal (CAP_CODE) corresponding to the target capacitance value. Since the first control signal (CAP_CTL) is smaller than the second control signal (CAP_CODE) at the beginning, the first control signal (CAP_CTL) is added by 1 when the rising edge of the second clock signal (CK_R) arrives. During the comparison process, it is performed once for each clock cycle of the second clock signal (CK_R) until the first control signal (CAP_CTL) is equal to the second control signal (CAP_CODE), that is, the adjustment of the capacitor array from 0 to the target capacitance value is completed. Furthermore, the capacitance added each time is the smallest capacitance unit in the capacitance array, which has little effect on the oscillation waveform and the waveform changes smoothly.

[0062] Through the above scheme, during the crystal oscillator start-up process, the capacitance value of the capacitor array module is adjusted, and the crystal oscillator starts with the minimum load capacitance during the crystal oscillator start-up stage, thereby achieving rapid start-up, and during the start-up process, the load capacitance of the crystal oscillator is controlled by increasing the set capacitance value each time, thereby gradually adjusting the capacitance to the target capacitance, making the crystal oscillator oscillation amplitude change less, and finally completing rapid and smooth start-up. When the capacitor array adjustment is completed, the oscillation amplitude increases rapidly and finally reaches stability. Compared with the prior art, while achieving rapid start-up, the power consumption of the start-up process is reduced.

[0063] Furthermore, in a possible implementation, the crystal oscillator is a single external high-frequency crystal oscillator or a single external low-frequency crystal oscillator, and the crystal oscillator drive module, the capacitor array module, the capacitor array control module and the signal processing module are all arranged inside the chip.

[0064] The following is a detailed analysis of each module in the crystal oscillator control circuit in conjunction with the accompanying drawings.

[0065] like Figure 3 As shown in the figure, it is the implementation structure of a common crystal oscillator circuit, where a is an inverter structure. The power consumption of the crystal oscillator is positively correlated with the power supply voltage and the load capacitance. b and c are single-ended structures. Due to the use of a constant tail current, the power consumption is independent of the power supply voltage, but is related to the oscillation amplitude and load capacitance. d is a single-ended structure with an amplitude control module. The amplitude control module can detect the amplitude of the crystal oscillation voltage and give real-time control, thereby controlling the circuit power consumption. The power consumption of this circuit is independent of the power supply voltage, but is related to the oscillation amplitude and load capacitance.

[0066] like Figure 4 As shown in Figure 1, it is an equivalent model of the crystal oscillator, where Co, Rm, Cm and Lm are inherent parameters. C1 and C2 are the external load capacitors of the crystal oscillator, which can be made on the PCB or inside the chip, and the start-up time of the crystal oscillator can be adjusted by changing the size of the load capacitor. The start-up time τ of the crystal oscillator can be expressed by formula 1, where Re(Z C ) is the negative resistance of the oscillator circuit, which can be expressed by formula 2:

[0067]

[0068]

[0069] like Figure 5 As shown in Figure 1, for a 24MHz crystal oscillator, the load capacitance has a significant effect on the start-up time.

[0070] In one possible implementation, the capacitor array module includes: a plurality of capacitor components and a switch component connected between each capacitor component and a ground line, wherein each switch component is used to perform a switching action according to a first control signal (CAP_CTL) sent by the capacitor array control module to control whether the capacitor component connected to each switch component is connected to the capacitor array module.

[0071] In a possible implementation, the capacitor array module is also used to adjust the starting waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator, wherein the manner of changing the load capacitance value of the crystal oscillator includes one or more of the following: thermometer coding and binary coding.

[0072] Specifically, the capacitor components in the capacitor array module whose capacitance value change of the load capacitor of the crystal oscillator is greater than the preset threshold value adopt the capacitance thermometer coding method. The capacitor components in the capacitor array module whose capacitance value change of the load capacitor of the crystal oscillator is less than or equal to the preset threshold value adopt the binary coding method. Among them, the preset threshold value can be flexibly set according to the experience value or the actual scenario, and the embodiment of the present invention does not limit this.

[0073] like Figure 6 The figure shows a thermometer-coded capacitor array. Since only one unit capacitor is turned on or off each time it is adjusted, the impact on the oscillation waveform is small and the performance is good. The disadvantage is that a large number of switches are required and the controller needs to be decoded. Figure 7 The figure shows a binary-coded capacitor array. The advantage is that a small number of switches are required. For an N-bit array, only N switches are needed. The disadvantage is that when the capacitor is adjusted, the waveform is greatly disturbed and the performance is poor.

[0074] In a possible implementation, for a 10-bit capacitor array, if a thermometer-coded capacitor array is used, 2 10 That is 1024 switches; but if a binary coded capacitor array is used, only 10 switches are needed.

[0075] In order to balance performance and area, the thermometer-coded capacitor array and the binary-coded capacitor array can be combined and used, with the high-order thermometer-coded array and the low-order binary-coded array. This reduces the number of switches and the disturbance to the waveform when the capacitor is adjusted.

[0076] like Figure 8 The figure shows a capacitor array control module, which includes: a digital comparator 81 and a bidirectional counter 82 connected in sequence, wherein the digital comparator 81 is used to compare the first control signal (CAP_CTL) output by the capacitor array control module with the second control signal (CAP_CODE) corresponding to the target capacitance value, and output an adjustment signal (UP / DOWN) for adjusting the first control signal (CAP_CTL); the bidirectional counter 82 is used to count the adjustment signal (UP / DOWN) output by the digital comparator 81 under the control of the second clock signal (CK_R), and adjust the first control signal (CAP_CTL) according to the counting result.

[0077] The working principle of the capacitor array control module is that the digital comparator compares the first control signal (CAP_CTL) and the second control signal (CAP_CODE). If the first control signal (CAP_CTL) is greater than the second control signal (CAP_CODE), Up=0, Down=1. When the clock edge arrives, the bidirectional counter performs a subtraction operation, that is, the first control signal (CAP_CTL) is subtracted by 1, and then the next comparison is performed; if the first control signal (CAP_CTL) is less than the second control signal (CAP_CODE), Up=1, Down=0. When the clock edge arrives, the bidirectional counter performs a plus operation, that is, the first control signal (CAP_CTL) is plus 1, and then the next comparison is performed; if the first control signal (CAP_CTL) is equal to the second control signal (CAP_CODE), Up=0, Down=0. When the clock edge arrives, the bidirectional counter maintains the original value; after several comparison / counting cycles, the first control signal (CAP_CTL) is finally equal to the second control signal (CAP_CODE).

[0078] like Fig. 9As shown, the signal processing unit is composed of a delay unit 91 and a frequency divider 92. According to the principle of phase noise injection, the signal amplitude is adjusted at the highest point or the lowest point to minimize the interference to the signal. Therefore, the control clock of the counter can be delayed by the delay unit 91 to shift its phase (for example, 90 degrees) to achieve the best effect. The delay unit 91 has various structures, such as Fig.10 As shown, Fig.10 In a, an RC low-pass filter is used to delay the first clock signal (CLK_OSC). Fig.10 In b, multiple delay elements are connected in series to achieve the purpose of delay. After the delay, each time the oscillation signal reaches the peak, the capacitor array is adjusted to reduce the interference to the signal. The specific adjustment process is as follows: Fig.11 It should be noted that the clock of the bidirectional counter comes from the crystal oscillator itself. The capacitance increases gradually during the start-up phase. If the capacitance increases too quickly, the start-up amplitude will decrease, resulting in clock interruption. Therefore, in order to smoothly switch the load capacitance and avoid continuous and rapid changes in the load, the crystal oscillator clock is divided by the divider 92 to control the speed of capacitance adjustment.

[0079] like Fig.12 , Fig.13 In the process of starting the high-frequency crystal oscillator, the scheme provided by the embodiment of the present invention is compared with the starting waveform of the conventional scheme in the prior art. Fig.12 The sine wave shown is the output end of the crystal oscillator. Fig.13 The first clock signal (CLK_OSC) converted into a square wave waveform is shown. The first waveform is the crystal oscillator start-up waveform provided in the embodiment of the present invention. The crystal oscillator starts with the minimum load capacitance. The marked box is the period of gradual capacitance adjustment. It can be seen that the waveform is smooth when the capacitance is adjusted. After the capacitance adjustment is completed, the oscillation amplitude continues to increase and finally reaches stability. The second waveform is a conventional start-up waveform that starts with the target capacitance. Compared with the crystal oscillator start-up speed provided by this solution, it is much slower. Fig.13 It can be seen that the conventional start-up time is about 600 microseconds (μS), while this solution only requires 200μS, a difference of 400μS; the third waveform shows that the crystal oscillator starts with the minimum load capacitance, and after the start-up is completed, the capacitance is adjusted to the target capacitance at one time. Although this method starts quickly, the waveform has a large disturbance when adjusting the capacitance, and it takes some time to stabilize the oscillation amplitude of the waveform after adjusting the capacitance.

[0080] like Fig.14As shown, in the process of starting the low-frequency crystal oscillator, the scheme provided by the embodiment of the present invention is compared with the starting waveform of the conventional scheme in the prior art. Among them, the first waveform is the crystal oscillator starting waveform provided by the embodiment of the present invention. The crystal oscillator starts with the minimum load capacitance, and gradually adjusts the capacitance to the target capacitance during the starting process, and finally completes the fast and smooth starting; the second waveform is a conventional starting waveform that starts with the target capacitance, which is much slower than the crystal oscillator starting speed provided by this scheme. It can be seen from the figure that the conventional starting time is about 700 milliseconds (mS), while this scheme is only 40mS, which is 660mS faster.

[0081] Based on the same inventive concept, an embodiment of the present invention further provides an electronic device, including the crystal oscillator control circuit provided by an embodiment of the present invention.

[0082] Based on the same inventive idea, Fig.15 As shown, an embodiment of the present invention further provides a crystal oscillator start-up control method, which is used in the crystal oscillator control circuit provided in an embodiment of the present invention, and the method may include the following steps:

[0083] Step 1501: the crystal oscillator driving module drives the crystal oscillator to generate a first clock signal, and outputs the first clock signal to the signal processing module;

[0084] Step 1502: The signal processing module processes the preset clock signal to obtain a second clock signal, and outputs the second clock signal to the capacitor array control module;

[0085] Step 1503: the capacitor array control module generates a first control signal based on the second clock signal, and transmits the first control signal to the capacitor array module;

[0086] Step 1504 , the capacitor array module sets an initial capacitance value for crystal oscillator startup based on the control of the first control signal, and adjusts the crystal oscillator startup waveform and oscillation frequency by changing the crystal oscillator load capacitance value.

[0087] In a possible implementation, the capacitor array module adjusts the starting waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator, including:

[0088] When the crystal oscillator waveform reaches the preset amplitude, the load capacitance is controlled to reach the target capacitance value by increasing the set capacitance value each time, and the starting waveform and oscillation frequency of the crystal oscillator are adjusted.

[0089] Among them, the initial capacitance can be flexibly set according to the actual scenario. For example, the initial capacitance can be 0, or it can be the minimum capacitance value or a multiple of the minimum capacitance value of the capacitor array module. The set capacitance value can be the minimum capacitance adjustment amount of the capacitor array module, or it can be a multiple of the minimum capacitance adjustment amount of the capacitor array module. The embodiment of the present invention does not limit this.

[0090] In the process of increasing the set capacitance value each time to control the load capacitance of the crystal oscillator to reach the target capacitance value, the set capacitance value can be fixed, that is, the first control signal is specifically used to adjust the capacitance value of the capacitor array module starting with the initial capacitance, and the set capacitance value is uniformly increased at intervals to reach the target capacitance value; the set capacitance value can also be constantly changing, for example, when the adjustment starts, the set capacitance value is small, and as the adjustment time increases, the set capacitance value continues to increase. Of course, the set capacitance value can also change according to other rules or change randomly, and the embodiments of the present invention are not limited to this.

[0091] In one example, the first control signal (CAP_CTL) generated by the capacitor array control module can adjust the capacitance value of the capacitor array module starting from 0, and uniformly increase the capacitance value at intervals with the minimum capacitance adjustment value of the capacitor array module to reach the target capacitance value.

[0092] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0093] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A crystal oscillator control circuit, characterized in that: include: A crystal oscillator driving module, a signal processing module, a capacitor array control module, a capacitor array module and a crystal oscillator are connected in sequence, and the crystal oscillator driving module is also connected to the crystal oscillator, wherein: The crystal oscillator driving module is used to provide driving energy for the crystal oscillator and output the first clock signal generated by the crystal oscillator to the signal processing module; The signal processing module is used to perform preset processing on the received first clock signal to obtain a second clock signal, and output the second clock signal to the capacitor array control module; The capacitor array control module is used to generate a first control signal under the control of the second clock signal, and output the first control signal to the capacitor array module; The capacitor array module is used to set the initial capacitance value of the crystal oscillator under the control of the first control signal, and change the load capacitance value of the crystal oscillator with the initial capacitance value as the starting value to adjust the starting waveform and oscillation frequency of the crystal oscillator.

2. The circuit according to claim 1, characterized in that The capacitor array module adjusts the starting waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator, and is specifically used for: When the crystal oscillator waveform reaches a preset amplitude, the load capacitance of the crystal oscillator is controlled to reach a target capacitance value by increasing the set capacitance value each time, thereby adjusting the starting waveform and oscillation frequency of the crystal oscillator.

3. The circuit according to claim 1, characterized in that The crystal oscillator is a single external high-frequency crystal oscillator or a single external low-frequency crystal oscillator, and the crystal oscillator driving module, the capacitor array module, the capacitor array control module and the signal processing module are all arranged inside the chip.

4. The circuit according to claim 1, characterized in that The capacitor array module includes: a plurality of capacitor components and a switch component connected between each capacitor component and a ground line, wherein each switch component is used to perform a switch action according to a first control signal sent by the capacitor array control module to control whether the capacitor component connected to each switch component is connected to the capacitor array module.

5. The circuit according to claim 4, characterized in that The capacitor array module is also used to adjust the starting waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator. The method of changing the load capacitance value of the crystal oscillator includes one or more of the following: thermometer coding and binary coding.

6. The circuit according to claim 5, characterized in that The capacitor array module is specifically used for: A thermometer coding method is used for the capacitance component whose capacitance value change of the load capacitance of the crystal oscillator is greater than a preset threshold value; A binary coding method is used for the capacitor component whose capacitance value change of the load capacitor of the crystal oscillator is less than or equal to the preset threshold.

7. The circuit according to claim 2, characterized in that The capacitor array control module includes: a digital comparator and a bidirectional counter connected in sequence, wherein: The digital comparator is used to compare the first control signal output by the capacitor array control module with the second control signal corresponding to the target capacitance value, and output an adjustment signal for adjusting the first control signal; The bidirectional counter is used to count the adjustment signal output by the digital comparator under the control of the second clock signal, and adjust the first control signal according to the counting result.

8. The circuit according to claim 1, characterized in that The preset processing includes one or more of the following: frequency division processing and delay processing.

9. An electronic device, characterized in that: The electronic device comprises the crystal oscillator control circuit as claimed in any one of claims 1 to 8.

10. A crystal oscillator start-up control method, used in the crystal oscillator control circuit according to any one of claims 1 to 8, characterized in that: The method comprises: The crystal oscillator driving module drives the crystal oscillator to generate a first clock signal, and outputs the first clock signal to the signal processing module; The signal processing module is preset to process the first clock signal to obtain a second clock signal, and output the second clock signal to the capacitor array control module; The capacitor array control module generates a first control signal based on the second clock signal, and transmits the first control signal to the capacitor array module; The capacitor array module sets an initial capacitance value of the crystal oscillator based on the control of the first control signal, and changes the load capacitance value of the crystal oscillator with the initial capacitance value as a starting value to adjust the starting waveform and oscillation frequency of the crystal oscillator.

11. The method according to claim 10, characterized in that The capacitor array module adjusts the starting waveform and oscillation frequency of the crystal oscillator by changing the load capacitance value of the crystal oscillator, including: When the crystal oscillator waveform reaches a preset amplitude, the load capacitance is controlled to reach a target capacitance value by increasing the set capacitance value each time, thereby adjusting the starting waveform and oscillation frequency of the crystal oscillator.

Images