CN110729985B - Clock signal generation circuit and electronic equipment - Google Patents
Clock signal generation circuit and electronic equipment Download PDFInfo
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- CN110729985B CN110729985B CN201810788751.2A CN201810788751A CN110729985B CN 110729985 B CN110729985 B CN 110729985B CN 201810788751 A CN201810788751 A CN 201810788751A CN 110729985 B CN110729985 B CN 110729985B
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
- H03K3/01—Details
- H03K3/011—Modifications of generator to compensate for variations in physical values, e.g. voltage, temperature
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K5/00—Manipulating of pulses not covered by one of the other main groups of this subclass
- H03K5/13—Arrangements having a single output and transforming input signals into pulses delivered at desired time intervals
- H03K5/135—Arrangements having a single output and transforming input signals into pulses delivered at desired time intervals by the use of time reference signals, e.g. clock signals
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Abstract
A clock signal generation circuit and an electronic device, the circuit comprising: a ROSC module adapted to generate a clock signal; the reference clock module is connected with the ROSC module and is suitable for providing a reference clock signal; the temperature sensor is connected with the ROSC module and is suitable for sensing temperature; the voltage sensor is connected with the ROSC module and is suitable for sensing voltage; the storage module is connected with the temperature sensor, the voltage sensor and the ROSC module, and is suitable for storing a basic correction table, and fine adjustment data for temperature and voltage are recorded in the table; when the ROSC module is initialized, correcting the frequency of a clock signal by using a reference clock signal; otherwise, the ROSC module corrects the frequency of the clock signal according to the temperature and voltage search matched trimming data, and when the search time exceeds a preset threshold value, the frequency of the clock signal is corrected by utilizing the reference clock signal.
Description
Technical Field
The present invention relates to the field of electronic circuits, and in particular, to a clock signal generating circuit and an electronic device.
Background
In a conventional scheme, the Clock signal may be generated by using a Real Time Clock (RTC) chip. The RTC chip includes a crystal oscillator (crystal), and the price of the crystal oscillator is high, so that the cost of the RTC chip is high.
A Ring Oscillator (ROSC) may also generate a clock signal, but the ROSC has a disadvantage in that its oscillation frequency varies with the influence of external factors, and has low frequency accuracy and unstable frequency. The existing ROSC optimization scheme mainly adopts a process, voltage and temperature (Process Voltage Temperature, PVT for short) sensor to correct the frequency of a clock signal of the ROSC, but the PVT sensor is difficult to provide high-precision frequency in combination with the ROSC, and the clock precision cannot reach one part per million (1 ppm for short). Thus, in the circuit design of existing electronic devices, once a high precision clock signal is required, a relatively expensive RTC crystal is still employed.
At present, a clock signal generating circuit meeting the precision requirement and having lower cost is lacking.
Disclosure of Invention
The technical problem solved by the invention is to provide the clock signal generating circuit which meets the precision requirement and has lower cost.
To solve the above technical problem, an embodiment of the present invention provides a clock signal generating circuit, including: a ROSC module adapted to generate a clock signal; a reference clock module connected to the ROSC module, the reference clock module adapted to provide a reference clock signal; the temperature sensor is connected with the ROSC module and is suitable for sensing the working temperature of the ROSC module; the voltage sensor is connected with the ROSC module and is suitable for sensing the working voltage of the ROSC module; the storage module is connected with the temperature sensor, the voltage sensor and the ROSC module and is suitable for storing a basic correction table, and fine adjustment data for the working temperature and the working voltage are recorded in the basic correction table; when the ROSC module is initialized, the ROSC module corrects the frequency of the clock signal by using the reference clock signal; otherwise, the ROSC module searches matched trimming data in the basic correction table according to the working temperature and the working voltage, corrects the frequency of the clock signal based on the searched trimming data, and corrects the frequency of the clock signal by using the reference clock signal when the searching time exceeds a preset threshold value.
Optionally, when the search time exceeds a preset threshold, the ROSC module updates the basic correction table according to the reference clock signal, the working temperature and the working voltage after correcting the frequency of the clock signal by using the reference clock signal.
Optionally, the trimming data recorded in the basic correction table is further aimed at a process error, and when the ROSC module completes initialization, the matched trimming data is searched in the basic correction table according to the working temperature, the working voltage and the process error.
Optionally, the bit width of the fine tuning data for the process error recorded by the basic correction table is adapted to the lowest clock precision of the ROSC module.
Optionally, the ROSC module includes a counter, the clock signal is generated according to a counting result of the counter, and the basic correction table further stores overflow information of the counting result.
Optionally, timing information for searching the fine tuning data is also stored in the basic correction table.
Optionally, the storage module further stores: the fine adjustment correction table is suitable for recording fine adjustment data of errors caused by temperature changes; and the ROSC module searches matched trimming data in the basic correction table and the trimming correction table.
Optionally, the storage module is a nonvolatile memory.
Optionally, the reference clock module is a bluetooth module.
In order to solve the technical problem, the embodiment of the invention also provides electronic equipment, which comprises the clock signal generating circuit.
Compared with the prior art, the technical scheme of the embodiment of the invention has the following beneficial effects:
an embodiment of the present invention provides a clock signal generating circuit including: a ROSC module adapted to generate a clock signal; a reference clock module connected to the ROSC module, the reference clock module adapted to provide a reference clock signal; the temperature sensor is connected with the ROSC module and is suitable for sensing the working temperature of the ROSC module; the voltage sensor is connected with the ROSC module and is suitable for sensing the working voltage of the ROSC module; the storage module is connected with the temperature sensor, the voltage sensor and the ROSC module and is suitable for storing a basic correction table, and fine adjustment data for the working temperature and the working voltage are recorded in the basic correction table; when the ROSC module is initialized, the ROSC module corrects the frequency of the clock signal by using the reference clock signal; otherwise, the ROSC module searches matched trimming data in the basic correction table according to the working temperature and the working voltage, corrects the frequency of the clock signal based on the searched trimming data, and corrects the frequency of the clock signal by using the reference clock signal when the searching time exceeds a preset threshold value.
According to the technical scheme provided by the embodiment of the invention, the clock precision of the clock signal of the clock generation circuit can be ensured in the initialization process of the reference clock module for providing the reference clock signal, the clock signal is corrected by searching matched fine tuning data in the basic correction table, and once the searching time exceeds a preset threshold value, the frequency of the clock signal is corrected by using the reference clock signal. Compared with the mode of correcting by using PVT sensors, the method can correct the clock signals timely through reference clock signals in circuit operation, improves the clock accuracy of the clock signals generated by the ROSC module, and can meet the clock accuracy requirement and reduce the circuit cost compared with the mode of generating the clock signals by using RTC crystal oscillator.
Further, when the search time exceeds a preset threshold, the ROSC module updates the basic correction table according to the reference clock signal, the operating temperature and the operating voltage after correcting the frequency of the clock signal by using the reference clock signal. According to the technical scheme provided by the embodiment of the invention, the basic correction table can be updated, and the clock precision of the clock signal generated by the ROSC is gradually increased along with the time in a self-updating mode of the basic correction table.
Further, the fine tuning data recorded in the basic correction table is also aimed at the process error, and when the ROSC module completes initialization, the matched fine tuning data is searched in the basic correction table according to the working temperature, the working voltage and the process error. By fine tuning data for the process errors, frequency deviation of the ROSC module due to the process errors can be eliminated.
Further, the storage module further stores: the fine adjustment correction table is suitable for recording fine adjustment data of errors caused by temperature changes; and the ROSC module searches matched trimming data in the basic correction table and the trimming correction table. The frequency deviation generated by the ROSC module due to temperature change can be eliminated through the fine adjustment correction table, so that the frequency of the clock signal is corrected.
Drawings
FIG. 1 is a schematic block diagram of a clock signal generation circuit according to an embodiment of the present invention;
FIG. 2 is a graph showing the frequency versus temperature of a clock signal output by a typical ROSC module;
FIG. 3 is a schematic diagram showing frequency deviation generated by temperature variation at different times of the clock signal generating circuit shown in FIG. 1;
FIG. 4 is a flow chart of data update in a basic correction table stored by the clock signal generation circuit of FIG. 1;
FIG. 5 is a flow chart of an exemplary embodiment of step S4052 in FIG. 4;
fig. 6 is a block diagram showing an exemplary configuration of a clock signal generating circuit of the clock signal generating circuit shown in fig. 1.
Detailed Description
As to the background art, the existing clock signal generating circuit can use an RTC crystal oscillator to generate a clock signal, but the price of the RTC crystal oscillator is high; a Ring oscillator (Ring OSCillatior, abbreviated as ROSC) may be used in conjunction with a process, voltage, and temperature (Process Voltage Temperature, abbreviated as PVT) sensor to generate a clock signal, but the clock accuracy is difficult to reach 5ppm, and the high accuracy requirement of some specific electronic devices on the clock signal cannot be met.
The inventor finds that the ring oscillator is particularly suitable for being applied to various electronic devices due to the simple structure, low price and low power consumption. However, since the ring oscillator is not feedback-controlled, the frequency of the output clock signal is susceptible to factors such as process, operating temperature and power supply voltage, and there are problems of unstable frequency and low clock accuracy.
To solve the above technical problem, an embodiment of the present invention provides a clock signal generating circuit, including: a ROSC module adapted to generate a clock signal; a reference clock module connected to the ROSC module, the reference clock module adapted to provide a reference clock signal; the temperature sensor is connected with the ROSC module and is suitable for sensing the working temperature of the ROSC module; the voltage sensor is connected with the ROSC module and is suitable for sensing the working voltage of the ROSC module; the storage module is connected with the temperature sensor, the voltage sensor and the ROSC module and is suitable for storing a basic correction table, and fine adjustment data for the working temperature and the working voltage are recorded in the basic correction table; when the ROSC module is initialized, the ROSC module corrects the frequency of the clock signal by using the reference clock signal; otherwise, the ROSC module searches matched trimming data in the basic correction table according to the working temperature and the working voltage, corrects the frequency of the clock signal based on the searched trimming data, and corrects the frequency of the clock signal by using the reference clock signal when the searching time exceeds a preset threshold value.
According to the technical scheme provided by the embodiment of the invention, the reference clock module for providing the reference clock signal meeting the clock precision requirement is used in the initialization process, so that the clock precision of the clock signal generated in the scene can be ensured. Correcting based on the matched fine tuning data in the basic correction table, and determining whether the fine tuning data is suitable for correcting the frequency of the clock signal by comparing the searching time with a preset threshold value, and correcting the frequency of the clock signal by using the reference clock signal once the searching time exceeds the preset threshold value. Compared with the mode of correcting by using PVT sensors, the method can correct the clock signals timely through reference clock signals in circuit operation, improves the clock accuracy of the clock signals generated by the ROSC module, and can meet the clock accuracy requirement and reduce the cost compared with the mode of generating the clock signals by using RTC crystal oscillator.
In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.
Fig. 1 is a clock signal generation circuit according to an embodiment of the present invention. The clock signal generation circuit 100 may include: a memory module 1, a ROSC module 2, a reference clock module 3, a temperature sensor 4 and a voltage sensor 5.
Specifically, the ROSC module 2 is adapted to generate a clock signal. When the ROSC module 2 generates a clock signal, the generated current consumption is about 100nA, the power consumption is low, and the ROSC module 2 has the advantages of simple structure, small area and the like, does not need crystal oscillator, can replace an RTC module with relatively high price, and can be applied to various electronic equipment.
Clock accuracy may be affected by voltage drift or temperature changes due to the ROSC module 2. To ensure that the clock accuracy of the clock signal generated by the ROSC module 2 meets the requirements, the ROSC module 2 may be connected to a reference clock module 3 and correct the frequency of the generated clock signal according to the reference clock signal. In a specific implementation, when the ROSC module 2 is initialized, the ROSC module 2 may correct the frequency of the clock signal using the reference clock module 3.
Further, the operating temperature of the ROSC module 2 may range from-20 ℃ to 125 ℃. Those skilled in the art will appreciate that, with reference to fig. 2, in the implementation, the working temperature curve of the ring oscillator changes relatively smoothly between 0 ℃ and 80 ℃, and the clock accuracy of the ROSC clock signal is less affected, which is also a common temperature range in a typical application scenario of the clock generation circuit.
Further, in operation, the clock signal generating circuit 100 may search for the trimming data stored in the memory module 1 preferentially, correct the frequency of the clock signal using the matching trimming data, and if there is no matching trimming data, correct the frequency of the clock signal using the reference clock module 3.
As a non-limiting example, the clock signal generating circuit 100 may be operated for a long period of time within a specific temperature range (for example, between 10 ℃ and 40 ℃) for user usage reasons, and at this time, the trimming data corresponding to the operating temperature and the operating voltage (i.e., the trimming data recorded in the basic correction table) stored in the memory module 1 within the clock signal generating circuit 100 is mainly concentrated at the operating temperature of 10 ℃ to 40 ℃. Assuming that the clock signal generating circuit 100 is shifted to another working environment, the working temperature thereof is also changed, and assuming that the working temperature is changed to 45 ℃ to 80 ℃, since the data recorded in the memory module 1 is less or not recorded, at this time, the clock signal generating circuit 100 can correct the frequency of the output clock signal by using the reference clock signal provided by the reference clock module 3, and calculate fine adjustment data of the corresponding working temperature and working voltage according to the reference clock signal, and then record in the basic correction table. As time goes by, the fine tuning data corresponding to the working temperature and the working voltage in the basic correction table will be gradually perfected, and the frequency of correcting the clock signal by the reference clock module 3 will also be reduced, so that the circuit power consumption can be saved.
As a non-limiting example, the reference clock module 3 may be an external bluetooth low energy (Bluetooth Low Energy, BLE) module.
As yet another non-limiting example, the reference clock module 3 may be further selected from a Zigbee (Zigbee) module, a near field communication (Near Field Communication, abbreviated as NFC) module, a Wi-Fi module, and the like.
Further, the reference clock module 3 may be connected to the internet or other wireless communication network, and acquire a network clock signal as the reference clock signal. As is well known, the network clock signal is a clock signal with higher clock accuracy, and may be used to correct the frequency of the clock signal generated by the ROSC module 2. Alternatively, the reference clock module 3 may locally generate a precise clock signal as the reference clock signal.
As a non-limiting example, the ROSC module 2 outputs a clock signal of the clock signal generating circuit 100 according to a BLE signal (e.g., may be a network clock signal acquired by the BLE module). At this time, the precision of the clock signal can reach 5ppm or even 1ppm, and the clock precision of most electronic equipment can be met.
As a non-limiting example, the reference clock module 3 may be an internal module of the electronic device, and independently exist in the ROSC module 2; or may be integrated with the ROSC module 2.
Specifically, the memory module 1 stores trimming data adapted to compensate for frequency deviation of the clock signal generating circuit 100 for the operating temperature and the operating voltage of the ROSC module 2. The memory module 1 may be a non-volatile memory. The trimming data stored therein does not disappear after the power is turned off.
In order to ensure clock accuracy, the ROSC module 2 may be connected to a temperature sensor 4 and a voltage sensor 5, sense the current operating temperature and operating voltage of the ROSC module 2 in real time, search the basic correction table for trimming data corresponding to the operating temperature and operating voltage, and correct the frequency of the clock signal by using the reference clock signal provided by the reference clock module 3 if the search time exceeds a preset threshold.
Further, the clock signal generating circuit 100 may calculate trimming data of the current operating temperature and operating voltage according to the reference clock signal provided by the reference clock module 3, and record the calculated trimming data in the basic correction table in the memory module 1.
Specifically, the fine adjustment data may be recorded in a basic correction table (not shown) in the storage module 1. As the clock signal generation circuit 100 continues to operate, if the basic correction table does not record trimming data corresponding to the operating temperature and the operating voltage, the frequency of the clock signal may be corrected using the reference clock signal provided by the reference clock module 3. Meanwhile, the fine tuning data corresponding to the current working temperature and the working voltage can be calculated based on the reference clock signal and recorded in the basic correction table.
Otherwise, if the basic correction table records trimming data corresponding to the working temperature and the working voltage, and the search time used for searching the trimming data is within a preset threshold, the frequency deviation of the clock signal can be corrected based on the trimming data, wherein the preset threshold can be preset in the design stage of the clock signal generating circuit.
Specifically, the ROSC module 2 may connect the temperature sensor 4, the voltage sensor 5, and the reference clock module 3. Wherein the temperature sensor 4 may be configured to sense a wafer (die) temperature of the ROSC module 2, thereby obtaining the operating temperature.
Wherein the operating voltage may be sensed based on a voltage sensor 5 configured to sense a wafer voltage of the ROSC module 2. Wherein the voltage sensor 5 may connect the ROSC module 2 and the memory module 1. After determining the operating temperature and the operating voltage, the clock signal generation circuit 100 may look up a basic correction table stored in the memory module 1. If trimming data for the operating temperature and the operating voltage are recorded in the basic correction table and match the operating temperature and the operating voltage, the frequency of the clock signal may be corrected based on the trimming data searched when the search time is less than a preset threshold.
Further, the basic correction table records fine adjustment data of process errors for respective operating voltages and operating temperatures. The ROSC module 2 may also search the basic correction table for matching trimming data in combination with the operating temperature, operating voltage and process errors.
TABLE 1
Specifically, referring to Table 1, the basic correction table records the operating temperatures (T in Table 1 1 、T 2 、T N Etc.) and operating voltage (expressed in V in table 1 1 、V 2 、V N Etc.) for process errors can be used to configure the associated device to compensate for frequency deviations of the clock signal generated by the frequency oscillator. Wherein, the process error refers to ROS caused by the error generated by the operation speed of the deviceC generates a clock signal of varying frequency. However, under certain circumstances (e.g., operating temperature and operating voltage), the process errors of the fixed device operation, the fixed wafer, are determined values and the frequency variation of the clock signal of the ring oscillator will be determined values.
Thus, based on a given operating temperature and operating voltage, the frequency of the clock signal at a determined process error can be determined based on the process error.
Once the frequency deviation introduced by the working temperature, the working voltage and the process error is determined, compensation information of the frequency deviation under different conditions can be recorded in the basic correction table and can be recorded in the basic correction table as fine tuning data. When the clock signal generation circuit 100 starts to operate, the counter in the ROSC module 2 may correct the count result generated by the counter according to the trimming data, and the ROSC module 2 generates the clock signal according to the count result. Further, considering that the counter may overflow, a 1-bit overflow flag bit (overflow bit as shown in table 1) may be further included in the basic correction table to record overflow information of the counting result.
As a non-limiting example, the bit width of the fine tuning data for process errors recorded by the base correction table may be adapted to the lowest clock precision of the ROSC module 2 to meet the lowest precision requirement of the clock signal.
TABLE 2
Further, when the ROSC module 2 completes initialization, after searching the corresponding trimming data in the basic correction table according to the working temperature, the working voltage and the process error, the searching time may be recorded, and the searching time and the preset threshold may be compared to determine whether to correct the frequency of the clock signal by using the trimming data. As shown in table 1, the search time (i.e., timing information for searching the fine adjustment data) may be stored in the basic correction table.
Further, the memory module 1 is further adapted to store a trimming correction table (not shown in fig. 1) in which trimming data generated for the operating temperature change in the case of a fixed voltage are recorded. Referring to table 2, the trimming correction table has recorded therein trimming data for temperature change at a specific voltage and errors introduced for the operating temperature change.
In a specific implementation, if trimming data corresponding to the working temperatures and the working voltages sensed by the temperature sensor 4 and the voltage sensor 5 are recorded in the basic correction table, the data in the basic correction table may be called, and the clock signal generated by the ROSC module 2 may be determined by combining the trimming data in the trimming correction table. The time consumed in the calculation process is the search time. The basic correction table may record the search time using the timing information, and correct the frequency of the clock signal based on the searched fine adjustment data when the search time does not exceed the preset threshold.
Specifically, if time is stored simply by the past time and the current time under the condition of a given operating voltage, frequency deviation may be introduced due to the change of the operating temperature. When the introduced frequency deviation reaches a certain threshold value, the accuracy of the clock signal generated by the ROSC module 2 is lower, so that the temperature correction information can be added to represent the frequency deviation information introduced by twice sensed temperatures.
In a specific implementation, the temperature sensor 4 may sense the operating temperature in real time. Typically, the temperature change is relatively smooth and can be measured at a given operating voltage (e.g., operating voltage V as shown in Table 2 1 ) Next, a 1-bit floating point number is used to characterize the trim data caused by temperature changes. As shown in Table 2, the trim correction table may record relevant trim data, such as at operating voltage V 1 From operating temperature T, unchanged 1 To the working temperature T 2 Trimming data of the introduced frequency deviation.
More specifically, after each sensing of the operating temperature by the temperature sensor 4, a temperature error correction value may be determined from the sensed temperature and the clock signal may be generated in combination with the trimming data of the base correction table. The clock signal generating circuit 100 may sense the operating temperature based on the temperature sensor 4 in real time, calculate a frequency deviation introduced by each temperature change and corresponding trimming data, and store the trimming data in the trimming correction table. With the operation of the clock signal generating circuit 100, the fine adjustment data in the basic correction table and the fine adjustment correction table are more and more perfect, and the clock accuracy of the clock signal generated by the ROSC module 2 is gradually improved even if the reference clock signal provided by the reference clock module 3 is not used any more.
As a non-limiting example, given the operating voltage of the ROSC module 2, the frequency deviation of the clock signal caused by the temperature change can be calculated by the pythagorean theorem. Specifically, as shown in fig. 3, the hatched area is the frequency deviation from the past time T1 to the present time T2 due to the temperature change. The count value corresponding to the current time T2 may be determined according to the temperature of the current time T2 sensed by the temperature sensor 4, and similarly, the count value corresponding to the past time T1 may also be determined. Because the temperature change curve is smooth, the frequency deviation can be approximately calculated by using the Pythagorean theorem, and the frequency deviation introduced by the temperature change can be represented by using the correction information of the 1-bit floating point number so as to correct the clock signal, reduce the influence of the temperature change on the clock signal generated by the ROSC module 2, and further output the clock signal meeting the precision requirement.
The clock signal generating circuit 100 is similar to the design scheme of the operating voltage and the operating temperature recorded in the basic correction table, and here, a fixed operating temperature is used, and updating of the basic correction table and the fine adjustment correction table will be described taking an operating voltage change as an example. Wherein, the storage module 2 already stores a basic correction table and a fine adjustment correction table.
In short, when designing the ring oscillator based clock signal generation circuit 100, updating the operating voltages in the basic correction table is maintained, updated in time sequence, and requires the recorded operating voltages (e.g., from the operating voltage V 1 To an operating voltage V 2 ) The linear relationship is satisfied. When the clock signal generating circuit 100 is operated, if the operating voltage is linearly changed, the operating voltage is recorded in a basic correction table in the memory module 1 and updated according to time; otherwise, when the operating voltage change is small, the recorded data (e.g., the operating voltage V1 and the operating voltage V3) may be averaged as an updated voltage value. However, if the difference between the already recorded operating voltages (e.g., operating voltage V1 and operating voltage V3) is too large to satisfy the linear relationship, the recording of the operating voltage value may be abandoned. This is because if the data recorded in the base correction table is too different, it means that the clock accuracy of the clock signal corrected by the ROSC module 2 according to the trimming data in the base correction table will not meet the accuracy requirement.
Specifically, as shown in fig. 4, it is assumed that the operating temperature T 1 Operating voltage V 2 And fine tuning data corresponding thereto (i.e., data T shown in FIG. 4 1 V 2 Trimming data D-T 1 V 2 ) None are contained in the memory module 1. In this case, the existing operating temperature T in the basic correction table is used 1 Operating voltage V 1 Fine tuning data D-T is calculated to fine tuning data that corresponds 1 V 2 The main flow of (2) is as follows:
first, step S401 is performed, i.e., the search operation temperature T 1 Operating voltage V 1 (i.e., data T shown in FIG. 4) 1 V 1 )；
Next, step S402 is performed to determine whether the data T is recorded in the basic correction table 1 V 1 Corresponding trimming data;
if so, then step S4031 is performed, i.e., the basic correction table data T is called 1 V 1 Corresponding trimming data; otherwise, step S4032 is performed, namely, correcting the frequency of the clock signal generated by the ROSC module 2 by using the reference clock signal provided by the parameter clock module 3; and continues to step S4033, i.e. calculate the trimming data D-T using the reference clock signal 1 V 2 The values of (2) are recorded in the basic correction table, and the process is finished;
after step S4031 is executed, step S404 is executed, i.e. it is determined whether trimming data corresponding to the voltage change is recorded in the trimming correction table; if so, step S4051 is performed, i.e. the trimming data in the trimming correction table is called, and the data T in the basic correction table is combined 1 V 1 Corresponding trimming data are used for calculating trimming data D-T 1 V 2 Is a value of (2); if not, go to step S4052, i.e. utilize the data T in the base correction table 1 V 1 Corresponding fine adjustment data calculation data T 1 V 2 Corresponding trimming data, once the trimming data is obtained, executing step S406;
further, step S406 is performed, i.e., a search time is determined, which is a search time from the search data T 1 V 1 To calculate the fine tuning data D-T 1 V 2 All time spent;
further, step S407 is performed, namely comparing the search time with a preset threshold to determine whether the search time exceeds the preset threshold; if yes, step S4032 and step S4033 are executed, and the flow ends; if not, go to step S408, i.e. store data T 1 V 2 Corresponding trimming data D-T 1 V 2 The flow ends.
As a non-limiting example, as shown in fig. 5, the data T is calculated using the trimming data existing in the basic correction table 1 V 2 The specific implementation process of the corresponding trimming data (i.e. executing step S4052) may be as follows:
first, step S40521 is performed to determine whether the data T is recorded in the basic correction table 1 V 1 Sum data T 1 V 3 Wherein, FIG. 5 is represented by T 1 Indicating operating temperature, in V 1 、V 3 Representing an operating voltage; if step S4032 is otherwise performed, i.e. the clock signal is generated using the reference clock signal, reference may be made to step S4032 shown in fig. 4 until the end;
if yes, then executeStep S40522, determining data T 1 V 2 Whether or not a constraint condition is satisfied, the constraint condition being expressed in an inequality: t (T) 1 V 1 ≤T 1 V 2 ≤T 1 V 3 The method comprises the steps of carrying out a first treatment on the surface of the Thereafter, if inequality T 1 V 1 ≤T 1 V 2 ≤T 1 V 3 If not, step S40523 is performed, i.e. for the operating voltage V 1 And operating voltage V 3 Averaging to obtain data T 1 V 2 Then, the process goes to step S406; if yes, go to step S406;
after that, step S406 is performed, and the search time is determined, and reference may be made to step S406 shown in fig. 4 until the end.
It should be noted that the design scheme of the working temperature and the design scheme of the working voltage in the basic correction table are the same, and are not described herein.
Further, the correct counting result of the counter in the ROSC module 2 can be determined by using the point values of each working temperature and each working voltage recorded in the basic correction table and using each temperature and voltage variation value recorded in the fine adjustment correction table. According to the counting result, the ROSC module 2 can generate a clock signal meeting the clock precision requirement.
It will be appreciated by those skilled in the art that when the ring oscillator is in operation, the change in operating voltage or operating temperature may be rising or falling, and that in order to save the search time and ensure clock accuracy, trimming data of the rise in operating voltage or operating temperature and trimming data of the fall in operating voltage or operating temperature may be recorded separately in the memory module 1.
It should be noted that, due to reasons such as incorrect operation or circuit aging, when the reference clock module 3 is turned on, it may be first searched whether relevant trimming data is already recorded in the basic correction table, if not, the trimming data deduced according to the reference clock signal is recorded in the basic correction table, otherwise, the relevant trimming data recorded and the deduced trimming data are averaged, and the trimming data obtained by the averaging calculation is used to replace the existing trimming data.
From the above, the ROSC module 2 may configure related devices in combination with the process error correction table, the temperature error correction table, and the trimming data recorded in the trimming correction table to correct the frequency of the clock signal, so that the ROSC module 2 is not affected by temperature and process, and outputs the clock signal meeting the precision requirement.
The basic correction table and the fine adjustment correction table stored in the memory module 1 will be described below by taking the design of a perpetual calendar with an average error of one second per month and an accuracy of one second as an example.
As shown in fig. 6, the clock signal generation circuit 200 may include a memory module 1, a ROSC module 2, a reference clock module 3, a temperature sensor 4, and a voltage sensor 5. The external load module 6 receives the clock signal from the clock signal generation circuit 200.
Wherein the temperature sensor 4 is connected with the ROSC module 2; the storage module 1 is connected with the ROSC module 2, the temperature sensor 4 and the voltage sensor 5; the storage module 1 stores a basic correction table, and fine adjustment data aiming at the working temperature and the working voltage are recorded in the basic correction table; the basic correction table also records fine adjustment data aiming at the process errors; the storage module 1 further stores a trimming correction table, and trimming data of errors caused by working temperature changes under the condition of fixed working voltage is recorded in the trimming correction table.
It should be noted that, the working principles and working manners of the memory module 1, the ROSC module 2, the reference clock module 3, the temperature sensor 4 and the voltage sensor 5 shown in fig. 6 may refer to the memory module 1, the ROSC module 2, the reference clock module 3, the temperature sensor 4 and the voltage sensor 5 shown in fig. 1, respectively, which are not described herein again.
In specific implementation, if the average monthly error is only 1 second and the accuracy is 1 second, the clock accuracy that needs to be provided is 60 (seconds) ×60 (minutes) ×24 (hours) ×30 (months) = 2592000 seconds. By calculating log 2 2.592×10 7 <22, the clock signal generation circuit 200 needs to beThe trimming data corresponding to the frequency deviation due to the process error is recorded with 22 bits.
If the frequency of the ROSC module 2 employed is 4MHz, then log can be determined by calculation 2 4000000<22, may be implemented in a 4MHz ring oscillator during design. The number of bits of the counter may be adaptively adjusted according to the frequency of the ROSC module 2.
As a non-limiting example, if the frequency of the ROSC module 2 employed is 16MHz, log can be determined by calculation 2 16000000<25, at this time, 22 bits of the clock signal can be used as trimming data aiming at the process error of the ROSC module 2 at the working temperature and the working voltage so as to adapt to the minimum clock precision of the ROSC module 2, thereby meeting the requirements that the error is only 1 second per month and the precision is 1 second; while the remaining 3 bits may be reserved information bits. For example, it can be used for clock accuracy adjustment. Those skilled in the art will appreciate that if the clock accuracy requires an error of less than 1 second (e.g., milli-seconds or nano-seconds), the number of bits of trim data for the process error will increase, as will the storage space.
Compared with the existing clock signal generation circuit, the clock signal generation circuit provided by the embodiment of the invention can eliminate the influence of the process, voltage and temperature on the output clock signal of the ring oscillator, gradually perfects the trimming data in the basic correction table and the trimming correction table along with the time, records more and more trimming data aiming at the working temperature and the working voltage, and is easy to search matched trimming data in a preset threshold value, so that the clock accuracy of the clock signal generated by the ring oscillator can be ensured, and the power consumption of the clock signal generation circuit can be reduced.
The embodiment of the invention also discloses an electronic device, which comprises the clock signal generating circuit 100 (or 200) described in the embodiment shown in the above fig. 1 to 6. The electronic equipment can be Internet of things equipment such as intelligent home equipment and wearable equipment, and can also be other Internet of things equipment. By adopting the clock signal generating circuit provided by the embodiment of the invention, the working time of the electronic equipment can be prolonged.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.
Claims (10)
1. A clock signal generation circuit, comprising:
a ROSC module adapted to generate a clock signal;
a reference clock module connected to the ROSC module, the reference clock module adapted to provide a reference clock signal;
the temperature sensor is connected with the ROSC module and is suitable for sensing the working temperature of the ROSC module;
the voltage sensor is connected with the ROSC module and is suitable for sensing the working voltage of the ROSC module; the storage module is connected with the temperature sensor, the voltage sensor and the ROSC module and is suitable for storing a basic correction table, and fine adjustment data for the working temperature and the working voltage are recorded in the basic correction table;
when the ROSC module is initialized, the ROSC module corrects the frequency of the clock signal by using the reference clock signal; otherwise, the ROSC module searches the matched trimming data in the basic correction table according to the working temperature and the working voltage, corrects the frequency of the clock signal based on the searched trimming data when the matched trimming data is searched in the basic correction table, corrects the frequency of the clock signal by using the reference clock signal when the matched trimming data cannot be searched in the basic correction table, and corrects the frequency of the clock signal by using the reference clock signal when the searching time exceeds a preset threshold value.
2. The clock signal generation circuit of claim 1, wherein the ROSC module updates the base correction table based on the reference clock signal and the operating temperature and operating voltage after correcting the frequency of the clock signal with the reference clock signal when the search time exceeds a preset threshold.
3. The clock signal generation circuit of claim 1, wherein the trimming data recorded in the base correction table is further for process errors, and the ROSC module searches the base correction table for matching trimming data based on the operating temperature, operating voltage, and process errors when initialization is completed.
4. A clock signal generation circuit according to claim 3, wherein the bit width of the trimming data for process errors recorded by the base correction table is adapted to the lowest clock accuracy of the ROSC module.
5. The clock signal generation circuit of claim 1, wherein the ROSC module includes a counter, the clock signal is generated based on a count result of the counter, and the base correction table further stores overflow information of the count result.
6. The clock signal generation circuit of claim 1, wherein timing information for searching the fine adjustment data is also stored in the base correction table.
7. The clock signal generation circuit of claim 1, wherein the memory module further stores:
the fine adjustment correction table is suitable for recording fine adjustment data of errors caused by temperature changes;
and the ROSC module searches matched trimming data in the basic correction table and the trimming correction table.
8. The clock signal generation circuit of any one of claims 1 to 7, wherein the memory module is a nonvolatile memory.
9. The clock signal generation circuit of any one of claims 1 to 7, wherein the reference clock module is a bluetooth module.
10. An electronic device comprising the clock signal generation circuit of any one of claims 1 to 9.
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| CN103092258B (en) * | 2013-01-28 | 2016-08-24 | 深圳市汇顶科技股份有限公司 | Clock generation circuit self correcting system and bearing calibration thereof |
| CN103166604B (en) * | 2013-01-29 | 2015-10-28 | 殷明 | A kind of low-power consumption sheet internal clock produces circuit |
| TWI517565B (en) * | 2013-03-11 | 2016-01-11 | 聯詠科技股份有限公司 | Method and apparatus for self-calibration of driving capability and resistance of on-die termination |
| CN103346735A (en) * | 2013-06-13 | 2013-10-09 | 深圳市芯海科技有限公司 | Clock signal generation method and device of microcontroller and microcontroller |
| GB2521635A (en) * | 2013-12-24 | 2015-07-01 | Nordic Semiconductor Asa | Improved low-power oscillator |
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| CN107196626A (en) * | 2017-07-11 | 2017-09-22 | 珠海晶通科技有限公司 | A kind of clock generator with temperature-compensating and with fabrication error amendment |
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