An adaptive method for starting a passive crystal oscillator

Abstract

The application discloses a self-adaptive method for starting a passive crystal oscillator, and the method comprises the following steps: a. dividing a crystal oscillator starting process into N stages, each stage corresponding to a starting scheme; b. enabling the crystal oscillator to start; c. executing a first starting scheme to enter a starting process of a first stage; d. judging whether the crystal oscillator starts or not, and if not, executing step e; e. executing a next starting scheme to enter a starting process of a next stage; and f. repeatedly executing steps d-e until the crystal oscillator starts.

Description

Technical Field

[0001] This invention relates to crystal oscillator start-up schemes, and more particularly to a method for starting up passive crystal oscillators. Background Technology

[0002] Current crystal oscillator circuits mainly use the Pierce oscillator circuit model. When applying them, you only need to configure the appropriate peripheral circuits for the crystal oscillator, namely two external load capacitors C1 and C2, and the crystal oscillator can work normally. However, since crystal oscillation is a matching problem, due to the inconsistency of crystal oscillators, or differences in PCBs or product usage environments, some crystal oscillators often cannot start oscillating normally.

[0003] Furthermore, traditional passive crystal oscillator start-up systems lack monitoring and processing mechanisms. If the crystal oscillator fails to oscillate, the system will not attempt other solutions to restart the crystal oscillator.

[0004] Therefore, there is an urgent need for a solution that can respond when the crystal oscillator is not oscillating and help the crystal oscillator restart. Summary of the Invention

[0005] To overcome the above-mentioned technical problems, this invention proposes an adaptive method for passive crystal oscillator startup, which includes the following steps:

[0006] a. Divide the crystal oscillator startup process into N stages, with each stage corresponding to an oscillator startup scheme;

[0007] b. Enable the crystal oscillator to start oscillation;

[0008] c. Execute the first vibration initiation scheme and enter the first stage of the vibration initiation process;

[0009] d. Determine whether the crystal oscillator is oscillating. If it is not oscillating, proceed to step e.

[0010] e. Execute the next vibration start-up scheme and enter the next stage of the vibration start-up process;

[0011] f. Repeat step de until the crystal oscillator starts oscillating.

[0012] In one embodiment, after the crystal oscillator starts oscillating, it further includes:

[0013] Determine whether the preheating time of the crystal oscillator has ended; if it has, the oscillation process ends; if it has not ended, continue to determine whether the preheating time of the crystal oscillator has ended.

[0014] In one embodiment, the first oscillation scheme is a traditional excitation method.

[0015] In one embodiment, when step e is executed for the first time, the next oscillation scheme is a combination of the traditional excitation method and the first disturbance excitation method.

[0016] In one embodiment, the first perturbation excitation scheme uses a sinusoidal signal as the excitation signal.

[0017] In one embodiment, when step e is executed for the second time, the next oscillation scheme is a combination of the traditional excitation method and the second disturbance excitation method.

[0018] In one embodiment, the second perturbation excitation scheme uses a square wave signal as the excitation signal.

[0019] In one embodiment, when step e is executed for the third time, the next oscillation scheme is a combination of the traditional excitation method and the method of adjusting the crystal oscillator drive circuit parameters.

[0020] In one embodiment, when step e is performed for the fourth time, the next oscillation scheme is to replace the crystal oscillator drive circuit.

[0021] In one embodiment, the conventional excitation method employs a Pierce oscillator circuit.

[0022] The adaptive method for passive crystal oscillator startup of this invention introduces a crystal oscillator startup detection and processing mechanism. If the crystal oscillator is detected as not oscillating, different schemes are used in a polling and switching manner to improve the success rate of crystal oscillator startup. This invention divides the crystal oscillator startup process into multiple stages, constantly detecting whether the crystal oscillator is oscillating. Once the crystal oscillator fails to oscillate, the system will respond accordingly, enter the next stage, and try other driving schemes to help the crystal oscillator restart. Attached Figure Description

[0023] The above-described invention and the following detailed description will be better understood when read in conjunction with the accompanying drawings. It should be noted that the drawings are merely examples of the claimed invention. In the drawings, the same reference numerals represent the same or similar elements.

[0024] Figure 1 A general flowchart of an adaptive method for passive crystal oscillator start-up according to an embodiment of the present invention is shown;

[0025] Figure 2 This paper illustrates a design example of dividing the oscillation start-up process into two stages in an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention.

[0026] Figure 3 A flowchart of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention is shown, wherein the starting process is divided into two stages;

[0027] Figure 4 This paper illustrates a design example of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention, which divides the oscillation process into three stages.

[0028] Figure 5 A flowchart of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention is shown, wherein the starting process is divided into three stages;

[0029] Figure 6 This paper illustrates a design example of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention, which divides the starting process into four stages.

[0030] Figure 7 A flowchart of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention is shown, wherein the starting process is divided into four stages;

[0031] Figure 8 This paper illustrates a design example of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention, which divides the oscillation process into five stages.

[0032] Figure 9 A flowchart of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention is shown, wherein the starting process is divided into five stages. Detailed Implementation

[0033] The following detailed description of the features and advantages of the present invention is sufficient to enable any person skilled in the art to understand the technical content of the present invention and implement it accordingly. Furthermore, based on the specification, claims and drawings disclosed herein, those skilled in the art can easily understand the related objects and advantages of the present invention.

[0034] Traditional passive crystal oscillator starting systems simply provide a drive stimulus without any systematic detection or processing mechanism. Once the drive stimulus is applied, the crystal fails to oscillate, and no further action is taken. This type of system is overly simplistic. Due to differences in the crystal oscillator, PCB, or product's operating environment, some products often exhibit abnormal crystal oscillator starting. To improve the probability of crystal oscillator starting and reduce the failure rate of crystal oscillator starting in products, there is a pressing need for a method to improve the success rate of passive crystal oscillator starting.

[0035] The adaptive scheme is implemented as follows: the crystal oscillator startup process is divided into N stages, and the crystal oscillator startup is monitored in real time. If the startup in stage 1 fails, the process proceeds to stage 2, the startup scheme is changed, and the startup continues. If the startup in stage 2 fails, the process proceeds to stage 3, the startup scheme is changed, and the startup continues. This process is repeated until the preheating time of the crystal oscillator ends. This can greatly improve the success rate of crystal oscillator startup.

[0036] To overcome the aforementioned technical problems, this invention proposes an adaptive method for passive crystal oscillator startup. This method introduces a crystal oscillator startup detection and processing mechanism. If the crystal oscillator fails to oscillate, different schemes are used in a polling and switching process to improve the success rate of startup. This invention divides the crystal oscillator startup process into multiple stages, continuously detecting whether the crystal oscillator is oscillating. Once the crystal oscillator fails to oscillate, the system responds accordingly, entering the next stage to try other driving schemes, thereby helping the crystal oscillator to restart.

[0037] Figure 1 A flowchart of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention is shown. This method divides the crystal oscillator starting process into N (N>1) stages, each stage corresponding to an oscillation scheme, thus providing a total of N oscillation schemes. The method includes, but is not limited to, the following steps:

[0038] Step 101: Enable the crystal oscillator to start oscillation;

[0039] Step 102: Execute the first vibration start-up scheme and enter the first stage of the vibration start-up process;

[0040] Step 103: Determine if the crystal oscillator is oscillating. If it is, proceed to step 109; if it is not, proceed to step 104.

[0041] Step 104: Switch to the second vibration start-up scheme and enter the second stage of the vibration start-up process;

[0042] Step 105: Determine if the crystal oscillator is oscillating. If it is, proceed to step 109; if it is not, proceed to step 106.

[0043] Step 106: Switch to execute the third vibration start-up scheme and enter the third stage of the vibration start-up process;

[0044] Step 107: Determine if the crystal oscillator is oscillating. If it is, proceed to step 109; if it is not, proceed to step 108.

[0045] Step 108: Switch to execute the Nth oscillation scheme and enter the Nth stage of the oscillation process;

[0046] Step 109: Determine whether the crystal oscillator preheating time has ended. If it has, the oscillation process ends; if it has not, continue to determine whether the crystal oscillator preheating time has ended.

[0047] Figure 2 This paper illustrates a design example of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention, which divides the oscillation process into two stages.

[0048] The oscillation process is divided into two stages: the first stage (t0~t1, also known as stage 1) and the second stage (t1~t2, also known as stage 2).

[0049] The first stage is the disturbance-free stage, which corresponds to the first oscillation scheme. This first oscillation scheme adopts a disturbance-free excitation method, namely the traditional excitation method.

[0050] The second stage is the disturbance stage, which corresponds to the second vibration initiation scheme, which adopts a combination of traditional excitation method and disturbance excitation method.

[0051] In one embodiment, the disturbance excitation may be an excitation signal such as a sinusoidal signal or a pulse signal.

[0052] Figure 3 A flowchart illustrating an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention is shown, wherein the starting process is divided into two stages. The method includes, but is not limited to, the following steps:

[0053] Step 301: Enable crystal oscillator to start oscillation;

[0054] Step 302: Excitation is provided using a traditional driving method, and the first stage of the oscillation process begins;

[0055] Step 303: Determine if the crystal oscillator is oscillating. If it is oscillating, proceed to step 305; if it is not oscillating, proceed to step 304.

[0056] Step 304: Using a combination of traditional excitation and disturbance excitation methods, the second stage of the oscillation process begins;

[0057] Step 305: Determine whether the crystal oscillator preheating time has ended. If it has, the oscillation process ends; if it has not, continue to determine whether the crystal oscillator preheating time has ended.

[0058] Figure 4 This paper presents a design example of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention, which divides the starting process into three stages.

[0059] The oscillation process is divided into three stages: the first stage (t0~t1, also known as stage 1), the second stage (t1~t2, also known as stage 2), and the third stage (t2~t3, also known as stage 3).

[0060] The first stage is the disturbance-free stage, which corresponds to the first oscillation scheme. This first oscillation scheme adopts a disturbance-free excitation method, namely the traditional excitation method.

[0061] The second stage is the first disturbance stage, which corresponds to the second vibration initiation scheme. This second vibration initiation scheme adopts the traditional excitation method + the first disturbance excitation method.

[0062] The third stage is the second disturbance stage, which corresponds to the third vibration initiation scheme. This third vibration initiation scheme adopts the traditional excitation method + the second disturbance excitation method.

[0063] The first and second perturbation excitation methods involve different perturbations. For example, the first perturbation excitation method can use a sine wave signal as the excitation signal, while the second perturbation excitation method can use a square wave signal as the excitation signal.

[0064] Figure 5 A flowchart illustrating an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention is shown, wherein the starting process is divided into three stages. The method includes, but is not limited to, the following steps:

[0065] Step 501: Enable crystal oscillator to start oscillation;

[0066] Step 502: Excitation is provided using a traditional driving method to enter the first stage of the oscillation process;

[0067] Step 503: Determine if the crystal oscillator is oscillating. If it is oscillating, proceed to step 507; if it is not oscillating, proceed to step 504.

[0068] Step 504: Combining the traditional excitation method with the first disturbance excitation method, the second stage of the oscillation process begins;

[0069] Step 505: Determine if the crystal oscillator is oscillating. If it is oscillating, proceed to step 507; if it is not oscillating, proceed to step 506.

[0070] Step 506: Combining the traditional excitation method and the second disturbance excitation method, the third stage of the oscillation process begins;

[0071] Step 507: Determine whether the crystal oscillator preheating time has ended. If it has, the oscillation process ends; if it has not, continue to determine whether the crystal oscillator preheating time has ended.

[0072] Figure 6 This paper presents a design example of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention, which divides the starting process into four stages.

[0073] The oscillation process is divided into four stages: the first stage (t0~t1, also known as stage 1), the second stage (t1~t2, also known as stage 2), the third stage (t2~t3, also known as stage 3), and the fourth stage (t3~t4, also known as stage 4).

[0074] The first stage is the disturbance-free stage, which corresponds to the first oscillation scheme. This first oscillation scheme adopts a disturbance-free excitation method, namely the traditional excitation method.

[0075] The second stage is the first disturbance stage, which corresponds to the second vibration initiation scheme. This second vibration initiation scheme adopts the traditional excitation method + the first disturbance excitation method.

[0076] The third stage is the second disturbance stage, which corresponds to the third vibration initiation scheme. This third vibration initiation scheme adopts the traditional excitation method + the second disturbance excitation method.

[0077] The first and second perturbation excitation methods involve different perturbations. For example, the first perturbation excitation method can use a sine wave signal as the excitation signal, while the second perturbation excitation method can use a square wave signal as the excitation signal.

[0078] The fourth stage is the circuit parameter adjustment stage, which corresponds to the fourth oscillation scheme. This fourth oscillation scheme adopts the traditional excitation method plus the method of adjusting the crystal oscillator drive circuit parameters.

[0079] The methods for adjusting the crystal oscillator drive circuit parameters include adjusting the built-in load capacitor, adjusting the drive capability, and adjusting the feedback resistor.

[0080] Figure 7 A flowchart illustrating an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention is shown, wherein the starting process is divided into four stages. The method includes, but is not limited to, the following steps:

[0081] Step 701: Enable crystal oscillator to start oscillation;

[0082] Step 702: Excitation is provided using a traditional driving method to enter the first stage of the oscillation process;

[0083] Step 703: Determine if the crystal oscillator is oscillating. If it is oscillating, proceed to step 709; if it is not oscillating, proceed to step 704.

[0084] Step 704: Combining the traditional excitation method with the first disturbance excitation method, the second stage of the oscillation process begins;

[0085] Step 705: Determine if the crystal oscillator is oscillating. If it is oscillating, proceed to step 709; if it is not oscillating, proceed to step 706.

[0086] Step 706: Combining the traditional excitation method and the second disturbance excitation method, the third stage of the oscillation process begins;

[0087] Step 707: Determine if the crystal oscillator is oscillating. If it is oscillating, proceed to step 709; if it is not oscillating, proceed to step 708.

[0088] Step 708: Combining traditional excitation methods with adjusting crystal oscillator drive circuit parameters, the fourth stage of oscillation start-up process begins;

[0089] Step 709: Determine whether the crystal oscillator preheating time has ended. If it has, the oscillation process ends; if it has not, continue to determine whether the crystal oscillator preheating time has ended.

[0090] Figure 8 This paper presents a design example of an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention, which divides the starting process into five stages.

[0091] The oscillation process is divided into five stages: the first stage (t0 to t1, also known as stage 1), the second stage (t1 to t2, also known as stage 2), the third stage (t2 to t3, also known as stage 3), the fourth stage (t3 to t4, also known as stage 4), and the fifth stage (t4 to t5, also known as stage 5).

[0092] The first stage is the disturbance-free stage, which corresponds to the first oscillation scheme. This first oscillation scheme adopts a disturbance-free excitation method, namely the traditional excitation method.

[0093] The second stage is the first disturbance stage, which corresponds to the second vibration initiation scheme. This second vibration initiation scheme adopts the traditional excitation method + the first disturbance excitation method.

[0094] The third stage is the second disturbance stage, which corresponds to the third vibration initiation scheme. This third vibration initiation scheme adopts the traditional excitation method + the second disturbance excitation method.

[0095] The first and second perturbation excitation methods involve different perturbations. For example, the first perturbation excitation method can use a sine wave signal as the excitation signal, while the second perturbation excitation method can use a square wave signal as the excitation signal.

[0096] The fourth stage is the circuit parameter adjustment stage, which corresponds to the fourth oscillation scheme. This fourth oscillation scheme adopts the traditional excitation method plus the method of adjusting the crystal oscillator drive circuit parameters.

[0097] The methods for adjusting the crystal oscillator drive circuit parameters include adjusting the built-in load capacitor, adjusting the drive capability, and adjusting the feedback resistor.

[0098] The fifth stage is the replacement of the drive circuit, which corresponds to the fifth oscillation scheme, which adopts the method of replacing the crystal oscillator drive circuit.

[0099] Figure 9 A flowchart illustrating an adaptive method for starting a passive crystal oscillator according to an embodiment of the present invention is shown, wherein the starting process is divided into five stages. The method includes, but is not limited to, the following steps:

[0100] Step 901: Enable crystal oscillator to start oscillation;

[0101] Step 902: Excitation is provided using a traditional driving method, and the first stage of the oscillation process begins;

[0102] Step 903: Determine if the crystal oscillator is oscillating. If it is oscillating, proceed to step 911; if it is not oscillating, proceed to step 904.

[0103] Step 904: Combining the traditional excitation method with the first disturbance excitation method, the second stage of the oscillation process begins;

[0104] Step 905: Determine if the crystal oscillator is oscillating. If it is, proceed to step 911; if it is not, proceed to step 906.

[0105] Step 906: Combining the traditional excitation method and the second disturbance excitation method, the third stage of the oscillation process begins;

[0106] Step 907: Determine if the crystal oscillator is oscillating. If it is oscillating, proceed to step 911; if it is not oscillating, proceed to step 908.

[0107] Step 908: The fourth stage of the oscillation process begins by combining the traditional excitation method with the adjustment of the crystal oscillator drive circuit parameters.

[0108] Step 909: Determine if the crystal oscillator is oscillating. If it is oscillating, proceed to step 911; if it is not oscillating, proceed to step 910.

[0109] Step 910: By replacing the crystal oscillator drive circuit, proceed to the fifth stage of the oscillation start-up process;

[0110] Step 911: Determine whether the crystal oscillator preheating time has ended. If it has, the oscillation process ends; if it has not, continue to determine whether the crystal oscillator preheating time has ended.

[0111] It should be noted that the conventional excitation methods described in this invention include, for example, using a Pierce oscillator circuit. Conventional excitation methods refer to passive crystal oscillator excitation methods well-known to those skilled in the art; therefore, they will not be described in detail in this invention.

[0112] The terminology and expressions used herein are for descriptive purposes only, and the invention should not be limited to these terms and expressions. The use of these terms and expressions does not imply the exclusion of any illustrative and descriptive equivalent features (or parts thereof), and it should be recognized that various modifications that may exist should also be included within the scope of the claims. Other modifications, variations, and substitutions may also exist. Accordingly, the claims should be considered to cover all such equivalents.

[0113] Similarly, it should be noted that although the present invention has been described with reference to the specific embodiments described above, those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions can be made without departing from the spirit of the present invention. Therefore, any changes or modifications to the above embodiments within the scope of the essential spirit of the present invention will fall within the scope of the claims of this application.

Claims

1. An adaptive method for starting a passive crystal oscillator, characterized in that, The method includes: a. Divide the crystal oscillator startup process into N stages, each stage corresponding to an oscillator startup scheme, where N>1; b. Enable the crystal oscillator to start oscillation; c. Execute the first vibration start-up scheme and enter the first stage of the vibration start-up process; d. Determine whether the crystal oscillator is oscillating. If it is not oscillating, proceed to step e. e. Execute the next vibration start-up scheme and enter the next stage of the vibration start-up process; f. Repeat step de until the crystal oscillator starts oscillating; in, When step e is executed for the first time, the next oscillation scheme is a combination of the traditional excitation method and the first disturbance excitation method; When step e is executed for the second time, the next oscillation scheme is a combination of the traditional excitation method and the second disturbance excitation method; When step e is executed for the third time, the next oscillation scheme is a combination of the traditional excitation method and the method of adjusting the crystal oscillator drive circuit parameters; When step e is executed for the fourth time, the next oscillation scheme is to replace the crystal oscillator drive circuit.

2. The adaptive method for passive crystal oscillator starting as described in claim 1, characterized in that, After the crystal oscillator starts oscillating, it also includes: Determine whether the preheating time of the crystal oscillator has ended; if it has, the oscillation process ends; if it has not ended, continue to determine whether the preheating time of the crystal oscillator has ended.

3. The adaptive method for passive crystal oscillator starting as described in claim 1, characterized in that, The first oscillation scheme is a traditional excitation method.

4. The adaptive method for passive crystal oscillator starting as described in claim 1, characterized in that, The first disturbance excitation method uses a sinusoidal signal as the excitation signal.

5. The adaptive method for passive crystal oscillator starting as described in claim 1, characterized in that, The second disturbance excitation method uses a square wave signal as the excitation signal.

6. The adaptive method for passive crystal oscillator starting as described in claim 1, characterized in that, The traditional excitation method uses a Pierce oscillator circuit.

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