A flight time difference ranging module and its temperature drift compensation method

Abstract

An embodiment of the present application provides a time-of-flight ranging module and a temperature drift compensation method therefor. The module includes: a driving circuit and a mirror circuit. The mirror circuit receives the same voltage signal as the driving circuit, and the frequency change of the output signal of the mirror circuit characterizes the delay change of the output signal of the driving circuit relative to the input signal. The mirror circuit generates output signals with a first frequency and a second frequency at a calibration temperature and a current temperature respectively; the driving circuit amplifies the driving signal at the current temperature to obtain the temperature drift depth data of the current temperature relative to the calibration temperature; so that the processing circuit obtains the delay difference of the driving circuit from the calibration temperature to the current temperature according to the first frequency and the second frequency, obtains the temperature drift error of the driving circuit from the calibration temperature to the current temperature according to the delay difference and the temperature drift compensation coefficient of the driving circuit, and performs temperature drift compensation on the temperature drift depth data at the current temperature according to the temperature drift error.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of time-of-flight ranging, and in particular, to a time-of-flight ranging module and a temperature drift compensation method therefor. Background Art

[0002] Time-of-flight (TOF) ranging is a technique for measuring the distance to a target by measuring the time of flight of light. Among them, 3D time-of-flight ranging imaging technology has a wide range of applications in fields such as AR / VR and service robots. According to the principle of time-of-flight ranging, temperature change is an important cause of time-of-flight ranging error. The drive circuit is the core circuit module of the time-of-flight ranging module. The temperature drift of the devices in the drive circuit will cause a delay in the optical pulse signal, seriously affecting the measurement accuracy.

[0003] Therefore, calibrating the temperature drift generated by the drive circuit of time-of-flight ranging can improve the accuracy of time-of-flight ranging. Summary of the Invention

[0004] In view of this, the embodiments of the present application provide a time-of-flight ranging module and a temperature drift compensation method therefor, which can calibrate the temperature drift generated by the drive circuit of the time-of-flight ranging module and improve the measurement accuracy of the time-of-flight ranging module.

[0005] According to a first aspect of the embodiments of the present application, a time-of-flight ranging module is provided, including: a drive circuit and a mirror circuit. The mirror circuit receives the same voltage signal as the drive circuit, and the frequency change of the output signal of the mirror circuit characterizes the delay change of the output signal of the drive circuit relative to the input signal. The mirror circuit generates an output signal with a first frequency and an output signal with a second frequency at a calibration temperature and a current temperature respectively, and sends the output signal with the first frequency and the output signal with the second frequency to a processing circuit; the drive circuit amplifies a drive signal at the current temperature to obtain temperature drift depth data of the current temperature relative to the calibration temperature, and sends the temperature drift depth data at the current temperature to the processing circuit; so that the processing circuit obtains a delay difference of the drive circuit from the calibration temperature to the current temperature according to the first frequency and the second frequency, obtains a temperature drift error of the drive circuit from the calibration temperature to the current temperature according to the delay difference and the temperature drift compensation coefficient of the drive circuit, and performs temperature drift compensation on the temperature drift depth data at the current temperature according to the temperature drift error.

[0006] According to the second aspect of the embodiments of the present application, a time-of-flight ranging module is provided, including: a driving circuit, a mirror circuit, and a processing circuit. The mirror circuit receives the same voltage signal as the driving circuit, and the frequency change of the output signal of the mirror circuit represents the delay change of the output signal of the driving circuit relative to the input signal. The mirror circuit generates an output signal with a first frequency and an output signal with a second frequency at a calibration temperature and a current temperature respectively, and sends the output signal with the first frequency and the output signal with the second frequency to the processing circuit; the driving circuit amplifies the driving signal at the current temperature to obtain the temperature drift depth data of the current temperature relative to the calibration temperature, and sends the temperature drift depth data at the current temperature to the processing circuit; the processing circuit obtains the delay difference of the driving circuit from the calibration temperature to the current temperature according to the first frequency and the second frequency, obtains the temperature drift error of the driving circuit from the calibration temperature to the current temperature according to the delay difference and the temperature drift compensation coefficient of the driving circuit, and performs temperature drift compensation on the temperature drift depth data sensed at the current temperature according to the temperature drift error.

[0007] According to the third aspect of the embodiments of the present application, a temperature drift compensation method is provided, which is applied to a time-of-flight ranging module. The time-of-flight ranging module includes: a driving circuit and a mirror circuit. The mirror circuit receives the same voltage signal as the driving circuit, and the frequency change of the output signal of the mirror circuit represents the delay change of the output signal of the driving circuit relative to the input signal. The method includes: respectively obtaining an output signal with a first frequency and an output signal with a second frequency generated by the mirror circuit at a calibration temperature and a current temperature; obtaining the delay difference of the driving circuit from the calibration temperature to the current temperature according to the first frequency and the second frequency; obtaining the temperature drift error of the driving circuit from the calibration temperature to the current temperature according to the delay difference and the temperature drift compensation coefficient of the driving circuit; and performing temperature drift compensation on the temperature drift depth data sensed at the current temperature by the time-of-flight ranging module according to the temperature drift error.

[0008] According to the fourth aspect of the embodiments of the present application, an electronic device is provided, including the above-mentioned time-of-flight ranging module.

[0009] According to the time-of-flight ranging module and its temperature drift compensation method provided by the embodiments of the present application, the mirror circuit and the drive circuit receive the same voltage signal, and the frequency change of the output signal of the mirror circuit characterizes the delay change of the output signal of the drive circuit relative to the input signal. Therefore, according to the frequency change of the output signals of the mirror circuit at the reference temperature and the current temperature respectively, the embodiments of the present application accurately obtain the delay difference of the drive circuit from the reference temperature to the current temperature. According to the delay difference and the temperature drift compensation coefficient of the drive circuit, the embodiments of the present application calculate the temperature drift error of the drive circuit from the reference temperature to the current temperature, and perform temperature drift compensation on the temperature drift depth data sensed at the current temperature according to the temperature drift error. The embodiments of the present application can calibrate the temperature drift generated by the drive circuit without setting a temperature sensor and a temperature control device for the drive circuit of the time-of-flight ranging, improve the measurement accuracy of the time-of-flight ranging module, and improve the mass production reliability of the time-of-flight ranging module. Description of the Drawings

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings.

[0011] Figure 1 It is a simplified model diagram of the time-of-flight ranging module in an embodiment of the present application;

[0012] Figure 2 It is a schematic structural diagram of the time-of-flight ranging module in another embodiment of the present application;

[0013] Figure 3 It is a schematic structural diagram of the time-of-flight ranging module in still another embodiment of the present application;

[0014] Figure 4 It is a simplified model diagram of the drive circuit in the time-of-flight ranging module in still another embodiment of the present application;

[0015] Figure 5 For Figure 4 It is a schematic waveform diagram of the output signal of the drive circuit in;

[0016] Figure 6 It is a schematic diagram showing that there is a delay τ between the output signal and the input signal;

[0017] Figure 7 It is a simplified model diagram of a ring oscillator;

[0018] Figure 8 It is a schematic diagram showing the relationship between the calibrated temperature difference error and the calibrated delay difference;

[0019] Figure 9 Flow chart of the temperature drift compensation method in another embodiment of the present application;

[0020] Figure 10 Flow chart of the temperature drift compensation method in another embodiment of the present application. Detailed implementation manners

[0021] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings. For ease of description, in the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, in different embodiments, the detailed descriptions of the same components are omitted. It should be understood that the thickness, length, width, etc. of various components shown in the accompanying drawings in the embodiments of the present application, as well as the overall thickness, length, width, etc. of the integrated device are only for illustrative purposes and should not constitute any limitation to the present application.

[0022] It should be noted that on the premise of no conflict, the various embodiments described in the present application and / or the technical features in the various embodiments can be combined arbitrarily, and the technical solutions obtained after combination should also fall within the protection scope of the present application.

[0023] It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art better understand the embodiments of the present application, rather than limiting the scope of the embodiments of the present application.

[0024] It should also be understood that in the various embodiments of the present application, the magnitudes of the serial numbers of the various processes do not mean the order of execution, and the order of execution of the various processes should be determined by their functions and internal logics, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0025] It should also be understood that the terms used in the embodiments of the present application and the appended claims are only for the purpose of describing specific embodiments, rather than aiming to limit the embodiments of the present application. For example, the singular forms of "a", "above-mentioned", and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0026] As used herein, terms such as "first", "second", and "third" describe various components, components, regions, layers, and / or sections, but such components, components, regions, layers, and / or sections should not be limited by such terms. Such terms can only be used to distinguish one component, component, region, layer, or section from each other. For example, the terms "first", "second", and "third" do not imply a sequence or order when used herein, unless clearly indicated by the background content.

[0027] In addition, for ease of description, spatial relative terms such as "below", "lower", "above", "upper" and the like may be used herein to describe the relationship of one component or element to another component or element illustrated in the figures. In addition to the orientation depicted in the figures, the spatial relative terms are also intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations) and thus the spatial relative descriptors used herein may be interpreted accordingly.

[0028] The time-of-flight ranging module measures the distance by emitting a modulated light beam and measuring the time difference between the emission of the modulated light, its reflection from an object, and the reception of the reflected signal. The drive circuit is the core circuit of the time-of-flight ranging module. In different application scenarios, the drive circuit needs to process optical pulse signals up to 100 MHz to drive a vertical cavity surface emitting laser (VCSEL) to emit light. The temperature drift of the components in the drive circuit will cause a delay in the optical pulse signal, seriously affecting the measurement accuracy.

[0029] The time-of-flight ranging module usually calibrates the temperature drift generated by the drive circuit by integrating a temperature sensor into the drive circuit. The temperature sensor collects the temperature drift depth data d sensed by the time-of-flight ranging module at different temperatures i corresponding to the temperature t i . A reference temperature t 0 (such as 25 °C) is selected, and the temperature drift depth data d sensed by the time-of-flight ranging module at the reference temperature T0 0 is used as the reference temperature drift depth data. The pressure drift error Δe is calculated using formula (1) i , and the temperature difference Δt is calculated using formula (2) i , obtaining multiple sets of (Δe i , Δt i ), and then fitting to obtain formula (3) as the equation for calculating the temperature drift error based on temperature or establishing a correspondence table between temperature and temperature drift error.

[0030] where Δe i = d i - d 0 , formula (1), where i is a positive integer;

[0031] Δt i = t i - t 0 , formula (2);

[0032] E = f(Δt i ), formula (3).

[0033] Since the conversion relationship of the temperature sensor with respect to temperature is not necessarily linear, and the temperature drift characteristics of the devices in the drive circuit are also non-linear, Equation (3) is an equation of degree two or higher with respect to temperature. Due to this non-linear relationship, using Equation (3) or obtaining the temperature drift error by looking up the corresponding table of temperature and temperature drift error will result in a low calibration accuracy of the obtained temperature drift error.

[0034] Moreover, collecting multiple temperature data using a temperature sensor requires adding temperature control equipment (e.g., a temperature control box). If the heating efficiency of the temperature control equipment is insufficient or the temperature control is not precise enough, it will cause an increase in the error of the temperature data collected by the temperature sensor. Collecting multiple temperature data using a temperature sensor takes a long time. Installing each time-of-flight ranging module into the temperature control equipment increases the complexity of the mass production mechanization process of the time-of-flight ranging module and will also seriously affect the large-scale mass production of the time-of-flight ranging module.

[0035] Regarding the above technical problems, refer to Figure 1 , Figure 1 which is a simplified model diagram of the time-of-flight ranging module in the embodiments of the present application. The time-of-flight ranging module 1 in the embodiments of the present application includes: a drive circuit 11 and a mirror circuit 12. The mirror circuit 11 and the drive circuit 12 receive the same voltage signal, and the frequency change of the output signal of the mirror circuit 11 represents the delay change τ of the output signal of the drive circuit 12 relative to the input signal.

[0036] Since this delay τ changes with the change of temperature and has a non-linear relationship with the temperature change, the embodiments of the present application can obtain the change of the delay τ of the output signal of the drive circuit 12 relative to the input signal through the frequency change of the output signal of the mirror circuit 11.

[0037] In a specific implementation of an embodiment of the present application, refer to Figure 2 , the mirror circuit 11 and the drive circuit 12 are connected to the same voltage source, so as to receive the same voltage signal. The embodiments of the present application further ensure that the mirror circuit 11 and the drive circuit 12 receive the same voltage signal, avoiding the frequency change of the output signal of the mirror circuit 11 caused by the difference in the voltage signals received by the mirror circuit 11 and the drive circuit 12, and being unable to accurately represent the delay change of the output signal of the drive circuit 12 relative to the input signal.

[0038] The embodiments of the present application can also select that the mirror circuit 11 and the drive circuit 12 are not connected to the same voltage source, and only need to ensure that the mirror circuit 11 and the drive circuit 12 receive the same voltage signal through a relatively complex circuit design.

[0039] Specifically, refer to Figure 3, in the embodiment of the present application, the time-of-flight ranging module 1 sends the output signals of the driving circuit 11 and the mirror circuit 12 to the processing circuit 13 of the electronic device where the time-of-flight ranging module 1 is located. Usually, the processing circuit 13 is the processor (main control module) of the electronic device.

[0040] Specifically, refer to Figure 4 , the time-of-flight ranging module 1 in the embodiment of the present application further includes a processing circuit 13, and the processing circuit 13 receives the output signals sent by the driving circuit 11 and the mirror circuit 12.

[0041] The mirror circuit 11 generates an output signal of a first frequency f 0 and an output signal of a second frequency f i (where i is a positive integer) at the reference temperature T 0 and the current temperature T i , and sends the output signal of the first frequency f 0 and the output signal of the second frequency f i to the processing circuit 13.

[0042] The driving circuit 12 amplifies the driving signal at the current temperature T i to obtain the temperature drift depth data d i of the current temperature T 0 relative to the reference temperature T i , and sends the temperature drift depth data d i at the current temperature T i to the processing circuit 13.

[0043] The processing circuit 13 obtains the delay difference Δτ 0 of the driving circuit 12 changing from the reference temperature T i to the current temperature T 0 according to the first frequency f i and the second frequency f.

[0044] According to the delay difference Δτ and the temperature drift compensation coefficient k of the driving circuit 12, the temperature drift error Δacc 0 of the driving circuit 12 changing from the reference temperature T i to the current temperature T is obtained.

[0045] Perform temperature drift compensation on the temperature drift depth data d i at the current temperature T i according to the temperature drift error Δacc.

[0046] According to the time-of-flight ranging module and its temperature drift compensation method provided by the embodiments of the present application, the mirror circuit and the drive circuit receive the same voltage signal, and the frequency change of the output signal of the mirror circuit characterizes the delay change of the output signal of the drive circuit relative to the input signal. Therefore, according to the frequency change of the output signal of the mirror circuit at the reference temperature and the current temperature respectively, the embodiments of the present application accurately obtain the delay difference of the drive circuit from the reference temperature to the current temperature. According to the delay difference and the temperature drift compensation coefficient of the drive circuit, the embodiments of the present application calculate the temperature drift error of the drive circuit from the reference temperature to the current temperature, and perform temperature drift compensation on the temperature drift depth data sensed at the current temperature according to the temperature drift error. The embodiments of the present application can calibrate the temperature drift generated by the drive circuit without setting a temperature sensor and a temperature control device for the drive circuit of the time-of-flight ranging, improving the measurement accuracy of the time-of-flight ranging module and the mass production reliability of the time-of-flight ranging module.

[0047] Specifically, referring to Figure 5 , Figure 5 is a simplified model diagram of the drive circuit in the time-of-flight ranging module according to the embodiments of the present application. The drive circuit 12 receives an input signal with a given frequency, improves the driving ability of the input signal to achieve the purpose of driving a vertical cavity surface emitting laser (VCSEL), and realizes time-of-flight ranging.

[0048] Referring to Figure 6 , after the input signal is processed such as amplified, an output signal with a higher driving ability is generated, and there is a certain delay τ between the output signal and the input signal.

[0049] In a specific implementation of the embodiments of the present application, the mirror circuit 11 and the drive circuit 12 have the same basic units, and the mirror circuit 11 and the drive circuit 12 have an equal number of basic units. Among them, the basic unit is a basic circuit unit, for example: an inverter, an amplifier,

[0050] Therefore, the mirror circuit 11 and the drive circuit 12 receive the same voltage signal, pass through the same basic units, and the mirror circuit 11 and the drive circuit 12 will have the same delay. The embodiments of the present application use the change of the frequency of the output signal of the mirror circuit 11 at different temperatures to more accurately obtain the change of the delay of the drive circuit 12 at different temperatures. The embodiments of the present application perform accurate temperature drift error compensation on the temperature drift generated by the drive circuit, further improving the measurement accuracy and mass production reliability of the time-of-flight ranging module.

[0051] In another specific implementation of the embodiment of the present application, there may be certain differences between the basic units of the mirror circuit 11 and the drive circuit 12, and there may also be certain differences in the number of the mirror circuit 11 and the drive circuit 12. It is only necessary that the frequency change of the output signal of the mirror circuit 11 can characterize the delay change of the output signal of the drive circuit relative to the input signal.

[0052] Exemplarily, there may be other circuit elements in both the mirror circuit 11 and the drive circuit 12, such as current-limiting resistors and the like.

[0053] In another specific implementation of the embodiment of the present application, refer to Figure 7 , Figure 7 which is a simplified model diagram of the ring oscillator in the time-of-flight ranging module in the embodiment of the present application. For more convenient circuit design, the mirror circuit 11 is a ring oscillator. Exemplarily, the ring oscillator includes the same number of inverters as in the drive circuit.

[0054] The processing circuit 13 obtains the delay difference Δτ of the drive circuit 12 from the reference temperature T 0 to the current temperature T i according to the first frequency f 0 and the second frequency f i of the output signal of the ring oscillator.

[0055] Specifically, the delay difference Δτ at the current temperature T i is obtained by using formula (4).

[0056] Δτ = Δτ osc = 1 / 2 * (1 / f i - 1 / f 0 ), formula (4).

[0057] According to the delay difference Δτ and the temperature drift compensation coefficient k of the drive circuit 12, the temperature drift error Δacc of the drive circuit 12 from the reference temperature T0 to the current temperature T i is obtained.

[0058] Specifically, the temperature drift error Δacc at the current temperature T i is obtained by using formula (5).

[0059] Δacc = Δτ * k, formula (5).

[0060] Perform temperature drift compensation on the temperature drift depth data d i at the current temperature T i according to the temperature drift error Δacc.

[0061] Specifically, the temperature drift depth data d at the current temperature Ti is compensated for temperature drift by using formula (6) i to obtain the temperature drift depth data d' at the current temperature Ti after compensation i '.

[0062] d i ' = d i -Δacc, formula (6).

[0063] In another specific implementation of the embodiment of the present application, the calibration of the temperature drift compensation coefficient k includes:

[0064] Obtain at least two different voltages (V 1 , V 2 , …… V n ), where n is a positive integer greater than 2.

[0065] The processing circuit 13 obtains at least two calibrated pressure drift depth data (d 1 , d 2 , …… d n ) sensed by the time-of-flight ranging module 1, and according to the calibrated pressure drift depth data (d 1 , d 2 , …… d n ), uses formula (7) to obtain the pressure drift calibration error Δacc i.

[0066] Δacc i = d j -d j-1 , formula (7), where j is a positive integer less than or equal to n.

[0067] The processing circuit 13 obtains at least two calibrated output signals of different frequencies (f 1 , f 2 , …… f n ) output by the mirror circuit 11 at the at least two different voltages (V 1 , V 2 , …… V n ).

[0068] The processing circuit 13 obtains the calibrated delay difference Δτ oscj of the mirror circuit 11 according to formula (8), and the calibrated delay difference Δτ j of the drive circuit. The calibrated delay difference Δτ oscj of the mirror circuit 11 is equal to the calibrated delay difference Δτ j of the drive circuit.

[0069] Δτ j = Δτ oscj = 1 / 2*(1 / f j -1 / fj-1 ), formula (8), where j is a positive integer less than or equal to n.

[0070] The processing circuit 13 obtains the calibrated delay difference Δτ according to formula (9). j and the drift calibration error Δacc i, and obtains the temperature drift compensation coefficient k of the driving circuit.

[0071] K = f(Δaccj, Δτ i ), formula (9).

[0072] Specifically, formula (9) is as Figure 8 shown.

[0073] As Figure 8 shown, from formula (9), it can be seen that the temperature drift compensation coefficient k is a linear function of Δτ j .

[0074] Therefore, the method for obtaining the temperature drift compensation coefficient k in the embodiments of the present application is obtained through a linear function of Δτ j , and the accuracy of using the temperature drift compensation coefficient k for temperature drift compensation of the driving circuit is high. In the embodiments of the present application, the calibration of the temperature drift compensation coefficient k can be achieved by providing at least two different voltages, and the calibration of the temperature drift compensation coefficient k can be quickly completed without affecting other calibration processes in the time-of-flight ranging module.

[0075] In another specific implementation of the embodiments of the present application, when n = 2, two different voltages (V 1 , V 2 ) are provided, and at least two calibrated drift depth data (d 1 , d 2 ) are sensed.

[0076] The drift calibration error Δacc = d 2 - d 1 is calculated according to formula (7).

[0077] The processing circuit 13 obtains the calibrated output signals of the mirror circuit 11 output at two different frequencies (f 1 , f 2 ) at two different voltages (V 1 , V 2 ).

[0078] The calibrated delay difference Δτ = Δτ osc = 1 / 2 * (1 / f 2 - 1 / f 1 ) is calculated according to formula (8).

[0079] The temperature drift compensation coefficient k of the driving circuit = Δacc / Δτ.

[0080] Therefore, in the embodiment of the present application, by applying two different voltages, collecting two sets of data and performing calibration calculations based on the two sets of data, the calibration of the temperature drift compensation coefficient k can be completed. The calibration speed of the temperature drift compensation coefficient k is fast, further improving the mass production reliability.

[0081] In another specific implementation of the embodiment of the present application, in order to further improve the calibration accuracy of the temperature drift compensation coefficient k, the temperature fluctuation is less than 0.5 °C during the calibration process of the temperature drift compensation coefficient k.

[0082] In another specific implementation of the embodiment of the present application, the position where the mirror circuit 11 is located makes the delay difference change generated by it and the drive circuit 12 with temperature change the same.

[0083] Specifically, when the time-of-flight ranging module is a small chip, the mirror circuit 11 and the drive circuit 12 are relatively close, and the mirror circuit 11 and the drive circuit 12 generate the same delay difference with temperature change.

[0084] Specifically, when the time-of-flight ranging module is a large chip, the mirror circuit 11 and the drive circuit 12 are made relatively close, and the mirror circuit 11 and the drive circuit 12 generate the same delay difference with temperature change.

[0085] When the mirror circuit 11 and the drive circuit 12 generate the same delay difference with temperature change, it can ensure that the change of the frequency signal passing through the mirror circuit 11 with temperature change accurately reflects the delay difference generated by the drive circuit 12 with temperature change, further improving the measurement accuracy and mass production reliability of the time-of-flight ranging module.

[0086] Corresponding to the above module, the embodiment of the present application also provides a temperature drift compensation method, which is applied to the time-of-flight ranging module.

[0087] See Figure 9 , the method includes:

[0088] S1. Obtain the output signals of the first frequency and the second frequency generated by the mirror circuit at the reference temperature and the current temperature respectively.

[0089] S2. Obtain the delay difference of the drive circuit from the reference temperature to the current temperature according to the first frequency and the second frequency.

[0090] S3. Obtain the temperature drift error of the drive circuit from the reference temperature to the current temperature according to the delay difference and the temperature drift compensation coefficient of the drive circuit.

[0091] S4. Perform temperature drift compensation on the temperature drift depth data at the current temperature sensed by the time-of-flight ranging module according to the temperature drift error.

[0092] According to the time-of-flight ranging module and its temperature drift compensation method provided by the embodiments of the present application, the mirror circuit and the drive circuit receive the same voltage signal, and the frequency change of the output signal of the mirror circuit characterizes the delay change of the output signal of the drive circuit relative to the input signal. Therefore, according to the frequency changes of the output signals of the mirror circuit at the reference temperature and the current temperature respectively, the embodiments of the present application accurately obtain the delay difference of the drive circuit from the reference temperature to the current temperature. According to the delay difference and the temperature drift compensation coefficient of the drive circuit, the embodiments of the present application calculate the temperature drift error of the drive circuit from the reference temperature to the current temperature, and perform temperature drift compensation on the temperature drift depth data sensed at the current temperature according to the temperature drift error. The embodiments of the present application can calibrate the temperature drift generated by the drive circuit without setting a temperature sensor and a temperature control device for the drive circuit of the time-of-flight ranging, improving the measurement accuracy of the time-of-flight ranging module and the mass production reliability of the time-of-flight ranging module.

[0093] In another specific implementation of the embodiments of the present application, refer to Figure 10 , wherein, before the step S3, it further includes:

[0094] S5. Receive at least two different voltages, obtain at least two calibrated pressure drift depth data sensed by the time-of-flight ranging module, and obtain a pressure drift calibration error according to the calibrated pressure drift depth data.

[0095] S6. Obtain at least two calibrated output signals of the mirror circuit under the at least two different voltages, and obtain a calibrated delay difference of the drive circuit according to the calibrated output signals.

[0096] S7. Obtain a temperature drift compensation coefficient of the drive circuit according to the calibrated delay difference and the pressure drift calibration error.

[0097] Therefore, the way to obtain the temperature drift compensation coefficient in the embodiments of the present application is obtained through a linear function regarding the calibrated delay difference, and the accuracy of using the temperature drift compensation coefficient for temperature drift compensation of the drive circuit is high. The embodiments of the present application can calibrate the temperature drift compensation coefficient by making the voltage source provide at least two different voltages, can quickly complete the calibration of the temperature drift compensation coefficient, and has no influence on other calibration processes in the time-of-flight ranging module.

[0098] In another specific implementation of the embodiments of the present application, the voltage source provides two different voltages.

[0099] Therefore, in the embodiment of the present application, by applying two different voltages, collecting two sets of data, and performing calibration calculations based on the two sets of data, the calibration of the temperature drift compensation coefficient can be completed. The calibration speed of the temperature drift compensation coefficient is fast, further improving the mass production reliability.

[0100] In another specific implementation of the embodiment of the present application, in order to further improve the calibration accuracy of the temperature drift compensation coefficient k, the temperature fluctuation is less than 0.5 °C during the calibration process of the temperature drift compensation coefficient.

[0101] The present application also provides an electronic device, including any one of the above time-of-flight ranging modules.

[0102] According to the time-of-flight ranging module and its temperature drift compensation method provided by the embodiment of the present application, the mirror circuit and the drive circuit receive the same voltage signal, and the frequency change of the output signal of the mirror circuit characterizes the delay change of the output signal of the drive circuit relative to the input signal. Therefore, in the embodiment of the present application, according to the frequency change of the output signal of the mirror circuit at the reference temperature and the current temperature respectively, the delay difference of the drive circuit from the reference temperature to the current temperature is accurately obtained. In the embodiment of the present application, according to the delay difference and the temperature drift compensation coefficient of the drive circuit, the temperature drift error of the drive circuit from the reference temperature to the current temperature is calculated, and the temperature drift compensation is performed on the temperature drift depth data sensed at the current temperature according to the temperature drift error. In the embodiment of the present application, it is not necessary to set a temperature sensor and a temperature control device for the drive circuit of the time-of-flight ranging, and the temperature drift generated by the drive circuit can be calibrated, improving the measurement accuracy of the time-of-flight ranging module and the mass production reliability of the time-of-flight ranging module.

[0103] It should be noted that according to the needs of implementation, each component / step described in the embodiment of the present application can be split into more components / steps, or two or more components / steps or partial operations of the components / steps can be combined into new components / steps to achieve the purpose of the embodiment of the present application.

[0104] The above embodiments are only used to illustrate the embodiments of the present application, rather than to limit the embodiments of the present application. Those of ordinary skill in the relevant art can also make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application, and the patent protection scope of the embodiments of the present application shall be defined by the claims.

Claims

1. A time-of-flight ranging module, comprising: a driving circuit and a mirror circuit, the mirror circuit and the driving circuit receive the same voltage signal, and the frequency change of the output signal of the mirror circuit characterizes the delay change of the output signal of the driving circuit relative to the input signal, the mirror circuit generates an output signal with a first frequency and an output signal with a second frequency at a reference temperature and a current temperature respectively, and sends the output signal with the first frequency and the output signal with the second frequency to a processing circuit; the driving circuit amplifies a driving signal at the current temperature to obtain temperature drift depth data of the current temperature relative to a calibrated temperature, and sends the temperature drift depth data at the current temperature to the processing circuit; so that the processing circuit obtains a delay difference of the driving circuit from the reference temperature to the current temperature according to the first frequency and the second frequency, obtains a temperature drift error of the driving circuit from the reference temperature to the current temperature according to the delay difference and a temperature drift compensation coefficient of the driving circuit, and performs temperature drift compensation on the temperature drift depth data at the current temperature according to the temperature drift error.

2. The time-of-flight ranging module according to claim 1, wherein, the mirror circuit and the driving circuit include the same basic units, and the number of basic units in the mirror circuit and the driving circuit is equal.

3. The time-of-flight ranging module according to claim 2, wherein, the mirror circuit is a ring oscillator.

4. The time-of-flight ranging module according to claim 1, wherein, the position of the mirror circuit makes the delay difference change caused by temperature change of the mirror circuit and the driving circuit the same.

5. The time-of-flight ranging module according to claim 1, wherein, the mirror circuit and the driving circuit are connected to the same voltage source.

6. A time-of-flight ranging module, comprising: a driving circuit, a mirror circuit and a processing circuit, the mirror circuit and the driving circuit receive the same voltage signal, and the frequency change of the output signal of the mirror circuit characterizes the delay change of the output signal of the driving circuit relative to the input signal, the mirror circuit generates an output signal with a first frequency and an output signal with a second frequency at a reference temperature and a current temperature respectively, and sends the output signal with the first frequency and the output signal with the second frequency to the processing circuit; the driving circuit amplifies a driving signal at the current temperature to obtain temperature drift depth data relative to a calibrated temperature, and sends the temperature drift depth data at the current temperature to the processing circuit; the processing circuit obtains a delay difference of the driving circuit from the reference temperature to the current temperature according to the first frequency and the second frequency, obtains a temperature drift error of the driving circuit from the reference temperature to the current temperature according to the delay difference and a temperature drift compensation coefficient of the driving circuit, and performs temperature drift compensation on the temperature drift depth data sensed at the current temperature according to the temperature drift error.

7. The time-of-flight ranging module according to claim 6, wherein, The mirror circuit and the drive circuit include the same basic units, and the number of basic units in the mirror circuit is equal to that in the drive circuit.

8. The time-of-flight ranging module according to claim 7, wherein, the mirror circuit is a ring oscillator.

9. The time-of-flight ranging module according to claim 6, wherein, the position of the mirror circuit is such that the delay difference variation generated by it and the drive circuit with temperature change is the same.

10. The time-of-flight ranging module according to claim 6, wherein, the mirror circuit and the drive circuit are connected to the same voltage source.

11. A temperature drift compensation method applied to a time-of-flight ranging module, the time-of-flight ranging module comprising: a drive circuit and a mirror circuit, the mirror circuit and the drive circuit receive the same voltage signal, and the frequency change of the output signal of the mirror circuit characterizes the delay change of the output signal of the drive circuit relative to the input signal. The method includes: respectively obtaining an output signal with a first frequency and an output signal with a second frequency generated by the mirror circuit at a reference temperature and a current temperature; obtaining the delay difference of the drive circuit from the reference temperature to the current temperature according to the first frequency and the second frequency; obtaining the temperature drift error of the drive circuit from the reference temperature to the current temperature according to the delay difference and the temperature drift compensation coefficient of the drive circuit; performing temperature drift compensation on the temperature drift depth data sensed by the time-of-flight ranging module at the current temperature according to the temperature drift error.

12. The temperature drift compensation method according to claim 11, wherein, before obtaining the temperature drift error of the drive circuit from the reference temperature to the current temperature according to the delay difference and the temperature drift compensation coefficient of the drive circuit, it further includes: receiving at least two different voltages, obtaining at least two calibrated pressure drift depth data sensed by the time-of-flight ranging module, and obtaining a pressure drift calibration error according to the calibrated pressure drift depth data; obtaining at least two calibrated output signals of the mirror circuit at the at least two different voltages, and obtaining a calibrated delay difference of the drive circuit according to the calibrated output signals; calibrating the temperature drift compensation coefficient of the drive circuit according to the calibrated delay difference and the pressure drift calibration error.

13. The temperature drift compensation method according to claim 12, wherein, the voltage source provides two different voltages.

14. The temperature drift compensation method according to claim 12, wherein, the temperature fluctuation during the calibration process of the temperature drift compensation coefficient is less than 0.5 °C.

15. An electronic device comprising the time-of-flight ranging module according to any one of claims 1-10.

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