A method for measuring conversion time and conversion duration of analog-to-digital converter, analog-to-digital converter and single-chip microcomputer

Abstract

The present application provides a method for measuring the conversion moment and conversion duration of an analog-to-digital converter, an analog-to-digital converter and a single-chip microcomputer, and belongs to the technical field of analog-to-digital converters. It includes an analog-to-digital converter with multiple signal channels, and the multiple signal channels are set in a queue request mode, so that after the first channel signal is acquired, the second channel signal adjacent in sequence can be acquired immediately, so that the first channel signal sampling and the second channel signal sampling are continuous; the measurement includes first generating a calibration signal with a first period and a first starting phase, and then using the first signal channel of the analog-to-digital converter to sample the calibration signal, adjusting the duty cycle of the calibration signal, so that the edge of the calibration signal is aligned with the sampling time, so as to directly measure the conversion time according to the value of the duty cycle, the first period and the first starting phase, and by measuring the conversion time of the first signal channel and the second signal channel, the conversion duration is measured, thereby ensuring the authenticity and accuracy of the measurement result.

Description

Technical Field

[0001] The present application relates to the technical field of analog-to-digital converters, and in particular to a method for measuring the conversion moment and conversion duration of an analog-to-digital converter, an analog-to-digital converter, and a single-chip microcomputer. Background Art

[0002] Analog-to-Digital Converter (ADC), also known as AD converter, is an electronic device that converts analog signals into digital signals and is widely used. Since analog signals in many usage scenarios show large periodic fluctuations in the time domain, the analog signal values ​​obtained at different sampling times are different. Therefore, it is necessary to obtain the exact time of AD sampling in some occasions. For example, the current of a three-phase motor is divided into conduction and freewheeling stages in a MOS tube in a chopping cycle, causing its analog current signal to change continuously. In order to obtain the correct digital current signal of the chopping cycle, we cannot continuously sample and calculate the average current value. Instead, we obtain the precise sampling time and use the AD conversion at this sampling time to obtain the current value as the average current value of a complete chopping cycle. Sampling too early or too late will cause the sampled current value to be larger or smaller than the actual physical value.

[0003] At the same time, the AD conversion module is generally integrated into the microcontroller unit (MCU) to achieve precise control of the controller unit. However, precise control of the controller unit may require the acquisition of dozens or even hundreds of analog signals. There are usually only a few AD converters in common MCUs, so the acquisition of AD signals must be grouped, each group corresponds to an AD converter, and an AD converter needs to collect multiple signals and realize signal conversion. Usually, there is a sampling channel switching switch inside the AD converter, and the switch is connected to different channels to achieve sampling of different channel signals. However, since AD ​​conversion takes time, the difference between these sequentially collected signals at the sampling time needs to be accurately obtained in some occasions to facilitate signal compensation and conditioning. For example, the rotor position signal of a three-phase motor is two groups of sine and cosine analog signals, and its analog signal value changes with the angle (position) of the motor rotor rotation. Only by accurately knowing the conversion time and conversion duration of each signal channel in the AD converter can the collected rotor position signal be accurately compensated and conditioned.

[0004] In the prior art, the conversion time and conversion duration of the AD converter are usually estimated based on the parameters of the AD converter clock, AD conversion bit number, sampling and holding time, conversion operation mode, post-calibration time, etc. set by the software, or the conversion time and conversion duration of the AD converter are controlled by using precise trigger rules or sampling trigger programs. However, the above methods can only indirectly infer the conversion time and conversion duration of the AD converter, without considering the influence of parameter configuration errors, sampling circuits and conversion circuits nonlinear distortion, etc., and cannot achieve accurate acquisition of AD sampling time and conversion duration. Summary of the invention

[0005] In order to overcome the problem in the prior art that the conversion moment and conversion duration of an analog-to-digital converter are difficult to measure directly, the present application provides a method for measuring the conversion moment and conversion duration of an analog-to-digital converter, an analog-to-digital converter and a single-chip microcomputer, by constructing a calibration signal with a determined first period and a first starting phase, and by changing the duty cycle of the calibration signal so that the edge of the calibration signal is aligned with the sampling time, thereby directly measuring the conversion moment according to the value of the duty cycle, the first period and the first starting phase, and measuring the conversion moment of the first signal channel and the second signal channel to measure the conversion duration, thereby ensuring the authenticity and accuracy of the measurement results, and further solving the problems raised in the above-mentioned background technology.

[0006] The present application provides a method for measuring the conversion time and conversion duration of an analog-to-digital converter, comprising an analog-to-digital converter having multiple signal channels, wherein the multiple signal channels configure the order of AD sampling channels in a queue request manner, and the AD converter processes different signals in sequence according to the set order; the multiple signal channels include a first signal channel and a second signal channel that are successively subjected to AD conversion;

[0007] The steps for measuring the conversion moment and conversion duration include:

[0008] Determine the sampling period and sampling start phase of the analog-to-digital converter;

[0009] Generate a calibration signal having a first period and a first starting phase, wherein the first period is the same as the sampling period, and the first starting phase is the same as the sampling starting phase; the calibration signal has a high voltage value and a low voltage value; the calibration signal is set as a PWM signal;

[0010] The conversion time measurement process includes sampling the calibration signal using a first signal channel of an analog-to-digital converter, adjusting the duty cycle of the calibration signal so that the voltage value output by the first signal channel is between the high voltage value and the low voltage value of the calibration signal; obtaining the value of the duty cycle, and calculating the sampling time T1 of the first signal channel according to the value of the duty cycle, the first period and the first starting phase of the calibration signal;

[0011] In the same way, the sampling time T2 of the second signal channel is measured;

[0012] The difference between the sampling time T1 and the sampling time T2 is the conversion time of the analog-to-digital converter.

[0013] Adopting the above technical solution, firstly, the calibration signal is sampled by the first signal channel according to the actual sampling frequency and sampling starting phase, and the duty cycle of the calibration signal is adjusted so that the sampling time falls on the edge of the calibration signal, that is, the voltage value output by the first signal channel is between the high voltage value and the low voltage value of the calibration signal. Since the calibration signal is a PWM signal and its edge duration is extremely short, the edge time of the calibration signal can be calculated according to the value of the duty cycle, the first period and the first starting phase of the calibration signal; and since the sampling time coincides with the edge of the calibration signal at this time, the first sampling time, that is, the conversion time T1 of the first signal channel in the analog-to-digital converter, can be measured.

[0014] Furthermore, since the second signal channel and the first signal channel perform AD conversion in succession, that is, when the first signal channel completes signal conversion, the second signal channel immediately starts to convert the signal. And the conversion time of the analog-to-digital converter is usually much shorter than the first cycle, therefore, by obtaining the conversion time T1 of the first signal channel and the conversion time T2 of the second signal channel, the conversion time of the analog-to-digital converter can be measured; so as to complete the accurate measurement of the conversion time and conversion time of the analog-to-digital converter.

[0015] In some embodiments, determining a sampling period and a sampling start phase of an analog-to-digital converter includes:

[0016] The analog-to-digital converter sampling period and sampling start phase are set using a preset program;

[0017] or,

[0018] A trigger signal having a second period and a second starting phase is generated, and the trigger signal is set to a PWM signal; and the trigger signal is used to trigger the analog-to-digital converter to perform sampling; at this time, the second period and the second starting phase are the sampling period and sampling starting phase of the analog-to-digital converter.

[0019] By adopting the above technical scheme, the sampling period and sampling start phase of the analog-to-digital converter can be freely set through a preset program or trigger signal, and when the sampling period and sampling start phase of the analog-to-digital converter change, the actual conversion time and conversion duration of the analog-to-digital converter can still be measured, and the calibration signal can be directly generated according to the parameters in the preset program or the trigger signal, thereby improving the measurement efficiency.

[0020] In some embodiments, the high voltage value of the calibration signal is set to a reference voltage Vref of the AD converter, which is usually 5.0V or 3.3V;

[0021] The low voltage value of the calibration signal is set to Vgnd, which is usually around 0V;

[0022] The adjustment duty cycle of the calibration signal gradually increases from 0 to 100%, and when the duty cycle is 0, the voltage value output by the first signal channel is around 0V.

[0023] In some embodiments, the sampling time T1 = the time of the first starting phase + the first period * the value of the duty cycle.

[0024] In some embodiments, each of the plurality of signal channels is used to process the same type or the same group of signals.

[0025] In some embodiments, when the first signal channel completes converting the signal, the second signal channel starts sampling and converting the signal.

[0026] In some embodiments, 1 / 2 of the first cycle duration is greater than the conversion duration.

[0027] The present application also provides an analog-to-digital converter, the analog-to-digital converter having a plurality of signal channels, the plurality of signal channels including a first signal channel and a second signal channel connected thereto;

[0028] The analog-to-digital converter adopts the method for measuring the conversion time and conversion duration of the analog-to-digital converter as described in any of the above embodiments to calibrate the conversion time and conversion duration of each signal channel of the analog-to-digital converter.

[0029] By adopting the above technical solution, by measuring the conversion moment and conversion duration of the analog-to-digital converter, the actual values ​​of the conversion moment and conversion duration of the analog-to-digital converter can be accurately measured, so that it can be more accurately applied in technical fields that require precise control or sampling.

[0030] The present application also provides a single chip computer, comprising: at least one analog-to-digital converter, the analog-to-digital converter having a plurality of signal channels, the plurality of signal channels comprising a first signal channel and a second signal channel connected thereto;

[0031] The analog-to-digital converter adopts the method for measuring the conversion time and conversion duration of the analog-to-digital converter as described in any of the above embodiments to calibrate the conversion time and conversion duration of each signal channel of the analog-to-digital converter.

[0032] By adopting the above technical scheme, by measuring the conversion time and conversion duration of the analog-to-digital converter, the actual values ​​of the conversion time and conversion duration of each analog-to-digital converter can be accurately measured, thereby facilitating the single-chip microcomputer to accurately compensate and adjust the control unit according to the actual values ​​of the conversion time and conversion duration of each analog-to-digital converter, thereby improving the control accuracy and precision.

[0033] Other features and corresponding beneficial effects of the present invention are described in the latter part of the specification, and it should be understood that at least part of the beneficial effects become obvious from the description in the specification of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A simplified schematic diagram of the structure of an analog-to-digital converter provided in an embodiment of the present application;

[0035] Figure 2 A schematic diagram of a process for adjusting the duty cycle of a calibration signal so that a sampling moment is aligned with an edge of the calibration signal provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may extend based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0037] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0038] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description created by the present application, unless otherwise specified, "multiple" means two or more.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] See also Figure 1 and Figure 2 , Figure 1 A simplified schematic diagram of the structure of the analog-to-digital converter provided in an embodiment of the present application is shown in FIG. Figure 2 A schematic diagram of a process for adjusting the duty cycle of a calibration signal so that a sampling moment is aligned with an edge of the calibration signal provided in an embodiment of the present application.

[0043] like Figure 1 and Figure 2 As shown, the present application provides a method for measuring the conversion moment and conversion duration of an analog-to-digital converter, including an analog-to-digital converter having multiple signal channels, the multiple signal channels sequentially processing different signals in a set order; the multiple signal channels include a first signal channel and a second signal channel connected in sequence;

[0044] The steps for measuring the conversion moment and conversion duration include:

[0045] Determine the sampling period and sampling start phase of the analog-to-digital converter;

[0046] Generate a calibration signal having a first period and a first starting phase, wherein the first period is the same as the sampling period, and the first starting phase is the same as the sampling starting phase; the calibration signal has a high voltage value and a low voltage value; the calibration signal is set as a PWM signal;

[0047] The conversion time measurement process includes sampling the calibration signal using the first signal channel of the analog-to-digital converter, adjusting the duty cycle of the calibration signal so that the voltage value output by the first signal channel is between the high voltage value and the low voltage value of the calibration signal; obtaining the value of the duty cycle, and calculating the sampling time T1 of the first signal channel according to the value of the duty cycle, the first period and the first starting phase of the calibration signal;

[0048] In the same way, the sampling time T2 of the second signal channel is measured;

[0049] The difference between the sampling time T1 and the sampling time T2 is the conversion time of the analog-to-digital converter.

[0050] It should be noted that the analog-to-digital converter has a presumable conversion moment and conversion duration, and the presumed conversion moment and conversion duration can be determined by the method mentioned in the background technology; however, even between different analog-to-digital converters of the same batch, due to processing errors or changes in the applicable environment, there are still slight errors in the conversion moment and conversion duration between different analog-to-digital converters of the same model and the same batch. Therefore, in the use scenario of high-precision control, the analog-to-digital converter with a large error is difficult to judge the conversion moment and conversion duration of the analog-to-digital converter, resulting in a decrease in control accuracy.

[0051] Therefore, in the embodiment of the present application, the calibration signal is sampled by the first signal channel according to the actual sampling frequency and sampling start phase, and the duty cycle of the calibration signal is adjusted so that the sampling time falls on the edge of the calibration signal, that is, the voltage value output by the first signal channel is between the high voltage value and the low voltage value of the calibration signal. Since the calibration signal is a PWM signal and its edge duration is extremely short, the edge time of the calibration signal can be calculated based on the value of the duty cycle, the first cycle of the calibration signal and the first start phase; and since the sampling time coincides with the edge of the calibration signal at this time, the first sampling time, that is, the conversion time T1 of the first signal channel in the analog-to-digital converter, can be measured.

[0052] Furthermore, since the second signal channel is connected to the first signal channel, that is, when the first signal channel completes signal conversion, the second signal channel immediately starts to convert the signal. And the conversion time of the analog-to-digital converter is usually much shorter than the first cycle, therefore, by obtaining the conversion time T1 of the first signal channel and the conversion time T2 of the second signal channel, the conversion time of the analog-to-digital converter can be measured; so as to complete the accurate measurement of the conversion time and conversion time of the analog-to-digital converter.

[0053] like Figure 2 As shown, when the duty cycle of the calibration signal is low, the sampling time of the analog-to-digital converter can only collect and output the low voltage value of the calibration signal; when the duty cycle of the calibration signal is high, the sampling time of the analog-to-digital converter can only collect and output the high voltage value of the calibration signal; only when the duty cycle of the calibration signal is appropriate, the sampling time of the analog-to-digital converter collects the voltage value of the signal edge of the calibration signal, so that the voltage value output by the first signal channel is between the high voltage value and the low voltage value of the calibration signal. Therefore, the edge time of the calibration signal can be calculated according to the value of the duty cycle, the first period of the calibration signal and the first starting phase.

[0054] In one embodiment, determining the sampling period and sampling start phase of the analog-to-digital converter includes:

[0055] The sampling period and the sampling start phase of the analog-to-digital converter are set by a preset program;

[0056] or,

[0057] A trigger signal having a second period and a second starting phase is generated, and the trigger signal is set to a PWM signal; and the trigger signal is used to trigger the analog-to-digital converter for sampling; at this time, the second period and the second starting phase are the sampling period and sampling starting phase of the analog-to-digital converter.

[0058] The sampling period and sampling start phase of the analog-to-digital converter can be freely set through a preset program or trigger signal, and when the sampling period and sampling start phase of the analog-to-digital converter change, the actual conversion time and conversion duration of the analog-to-digital converter can still be measured, and the calibration signal can be directly generated according to the parameters in the preset program or the trigger signal, thereby improving the measurement efficiency.

[0059] In one embodiment, the high voltage value of the calibration signal is set to 5.0V or 3.3V;

[0060] The low voltage value of the calibration signal is set to 0V;

[0061] The adjustment duty cycle of the calibration signal gradually increases from 0 to 100%, and when the duty cycle is 0, the voltage value output by the first signal channel is 0V.

[0062] In one embodiment, the sampling time T1 = the time of the first starting phase + the first period * the value of the duty cycle.

[0063] In one embodiment, each of the multiple signal channels is used to process the same type or the same group of signals.

[0064] In one embodiment, when the first signal channel completes the conversion of the signal, the second signal channel starts sampling and converting the signal.

[0065] In one embodiment, 1 / 2 of the first cycle duration is greater than the conversion duration. It should be noted that in most scenarios, the first cycle duration is much greater than the conversion duration of the analog-to-digital converter, and there is a difference in magnitude. Therefore, the difference between the sampling time T1 and the sampling time T2 can be directly calculated as the conversion duration of the analog-to-digital converter.

[0066] In one usage scenario, an embodiment of the present application further provides an analog-to-digital converter, the analog-to-digital converter having a plurality of signal channels, the plurality of signal channels including a first signal channel and a second signal channel connected thereto;

[0067] The analog-to-digital converter may adopt the method for measuring the conversion time and conversion duration of the analog-to-digital converter as in any of the above embodiments to calibrate the conversion time and conversion duration of each signal channel of the analog-to-digital converter.

[0068] In one usage scenario, an embodiment of the present application further provides a single chip microcomputer, including: at least one analog-to-digital converter, the analog-to-digital converter having a plurality of signal channels, the plurality of signal channels including a first signal channel and a second signal channel connected thereto;

[0069] The analog-to-digital converter adopts the method for measuring the conversion time and conversion duration of the analog-to-digital converter as in any of the above embodiments to calibrate the conversion time and conversion duration of each signal channel of the analog-to-digital converter.

[0070] In one embodiment, the single chip microcomputer can realize precise control of the control unit according to the signal of the analog-to-digital converter.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring the conversion time and conversion duration of an analog-to-digital converter, characterized in that: An analog-to-digital converter having a plurality of signal channels is included, wherein the plurality of signal channels sequentially process different signals in an order set by software; the plurality of signal channels include a first signal channel and a second signal channel connected in sequence; The steps for measuring the conversion moment and conversion duration include: Determine the sampling period and sampling start phase of the analog-to-digital converter; Generate a calibration signal having a first period and a first starting phase, wherein the first period is the same as the sampling period, and the first starting phase is the same as the sampling starting phase; the calibration signal has a high voltage value and a low voltage value; the calibration signal is set as a PWM signal; The conversion time measurement process includes sampling the calibration signal using a first signal channel of an analog-to-digital converter, adjusting the duty cycle of the calibration signal so that the voltage value output by the first signal channel is between the high voltage value and the low voltage value of the calibration signal; obtaining the value of the duty cycle, and calculating the sampling time T1 of the first signal channel according to the value of the duty cycle, the first period and the first starting phase of the calibration signal; Sampling time T1 = time of the first starting phase + first period × value of duty cycle; In the same way, the sampling time T2 of the second signal channel is measured; The difference between the sampling time T1 and the sampling time T2 is the conversion time of the analog-to-digital converter.

2. The method for measuring the conversion time and conversion duration of an analog-to-digital converter according to claim 1, characterized in that: Determining the sampling period and sampling start phase of the analog-to-digital converter includes: The analog-to-digital converter sampling period and sampling start phase are set using a preset program; or, A trigger signal having a second period and a second starting phase is generated, and the trigger signal is set to a PWM signal; and the trigger signal is used to trigger the analog-to-digital converter to perform sampling; at this time, the second period and the second starting phase are the sampling period and sampling starting phase of the analog-to-digital converter.

3. The method for measuring the conversion time and conversion duration of an analog-to-digital converter according to claim 1, characterized in that: The high voltage value of the calibration signal is set as the reference voltage of the analog-to-digital converter, and the reference voltage is 5.0V or 3.3V; The low voltage value of the calibration signal is set to 0V; The adjustment duty cycle of the calibration signal gradually increases from 0 to 100%, and when the duty cycle is 0, the voltage value output by the first signal channel is 0V.

4. The method for measuring the conversion time and conversion duration of an analog-to-digital converter according to claim 1, characterized in that: Among the multiple signal channels, each signal channel is used to process the same type or the same group of signals.

5. The method for measuring the conversion time and conversion duration of an analog-to-digital converter according to claim 1, characterized in that: At the moment when the first signal channel completes the signal conversion, the second signal channel starts sampling and converting the signal.

6. The method for measuring the conversion time and conversion duration of an analog-to-digital converter according to claim 1, characterized in that: 1 / 2 of the first cycle duration is greater than the conversion duration.

7. An analog-to-digital converter, characterized in that: The analog-to-digital converter has a plurality of signal channels, the plurality of signal channels are arranged as a queue request and are sampled successively, and the plurality of signal channels include a first signal channel and a second signal channel for consecutive sampling; Wherein, the analog-to-digital converter adopts the method for measuring the conversion time and conversion duration of the analog-to-digital converter as described in any one of claims 1 to 6 to calibrate the conversion time and conversion duration of each signal channel of the analog-to-digital converter.

8. A single chip microcomputer, characterized in that: include: At least one analog-to-digital converter, the analog-to-digital converter having a plurality of signal channels arranged to queue requests and perform consecutive sampling, and the plurality of signal channels including a first signal channel and a second signal channel for consecutive sampling; Wherein, the analog-to-digital converter adopts the method for measuring the conversion time and conversion duration of the analog-to-digital converter as described in any one of claims 1 to 6 to calibrate the conversion time and conversion duration of each signal channel of the analog-to-digital converter.

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