A time-of-flight ranging module, overheat detection method and electronic device thereof

Abstract

The present application provides a time-of-flight ranging module, an overheat detection method and an electronic device thereof, which can detect the temperature of the driver chip based on a first temperature detection module to generate a first sensing signal, and compare the first sensing signal with a set first overheat threshold to determine whether the driver chip is in an overheat state, and the first overheat threshold range is 85 degrees to 125 degrees, so as to ensure that the time-of-flight ranging module can perform corresponding processing according to whether overheating occurs. Furthermore, the temperature of the light emitter can be detected based on a second temperature detection module to generate a second sensing signal, and compare the second sensing signal with a set second overheat threshold to determine whether the light emitter is in an overheat state, and the second overheat threshold range is 85 degrees to 110 degrees, so as to ensure that the time-of-flight ranging module can perform corresponding processing according to whether overheating occurs.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of time-of-flight ranging, and more particularly to a time-of-flight ranging module, an overheating detection method thereof, and an electronic device. Background Art

[0002] The time of flight (TOF) module is a technology that measures the distance between a target object and a reference position by using the light flight time.

[0003] The time-of-flight ranging module uses a driver chip to drive a light emitter such as a vertical cavity surface emitter (VCSEL) to emit a light source signal, which is then processed by an optical device to generate a modulated light signal. The modulated light signal is used to determine the distance between the target object and the reference position.

[0004] In order to ensure a good ranging effect, the driver chip needs to generate a large drive signal to drive the VCSEL, so that the light emitter emits a sufficiently powerful modulated light signal. As a result, the light emitter and the driver chip will overheat.

[0005] Therefore, how to detect whether the optical transmitter and driver chip are overheating has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] In view of this, an embodiment of the present application provides a time-of-flight ranging module, an overheating detection method and an electronic device thereof, which detect whether an optical transmitter or a driver chip is overheated to ensure that the time-of-flight ranging module can perform corresponding processing according to whether overheating occurs.

[0007] The technical solutions provided by the embodiments of this application are as follows:

[0008] A time-of-flight ranging module, comprising:

[0009] A driving chip, used for generating a driving signal;

[0010] A light source, comprising a light emitter and an optical device, wherein the light emitter is used to generate a light source signal according to the driving signal, and the optical device generates a modulated light signal according to the light source signal, wherein the modulated light signal is used to determine the distance between the target object and the reference position;

[0011] A first temperature detection module, used for detecting the temperature of the driver chip to generate a first sensing signal, the first sensing signal is used for comparing with a set first overheating threshold to determine whether the driver chip is in an overheating state, the first overheating threshold range is 85 degrees to 125 degrees;

[0012] The second temperature detection module is used to detect the temperature of the light emitter to generate a second sensing signal, and the second sensing signal is used to compare with a set second overheating threshold to determine whether the light emitter is in an overheating state, and the second overheating threshold range is 85 degrees to 110 degrees.

[0013] Optionally, the time-of-flight ranging module further includes: a photosensitive chip,

[0014] The photosensitive chip is used to control the driving chip to stop generating the driving signal when the driving chip is in an overheated state, or to control the light emitter to stop generating the light source signal when the light emitter is in an overheated state.

[0015] Optionally, the first temperature detection module is also used to send the first sensing signal to the main control chip of the electronic device where the time-of-flight ranging module is located, so that when the driving chip is in an overheated state, the main control chip controls the driving chip to stop generating the driving signal; and / or, the second temperature detection module is also used to send the second sensing signal to the main control chip, so that when the light emitter is in an overheated state, the main control chip controls the light emitter to stop generating the light source signal.

[0016] Optionally, the first temperature detection module includes a first thermistor circuit, a first filtering circuit, and an analog-to-digital conversion circuit. The first thermistor circuit is used to sense the temperature of the driver chip to generate a first sensing signal. The first filtering circuit is used to filter the first sensing signal. The analog-to-digital conversion circuit is used to perform analog-to-digital conversion on the filtered first sensing signal to obtain a first digital signal, which is compared with the set first overheating threshold to determine whether the driver chip is in an overheating state.

[0017] Optionally, the first thermistor circuit includes a first triode and a second triode:

[0018] The emitter of the first triode is connected to a first current source, and the base and collector of the first triode are both connected to the collector of the second triode, so that the first triode works under the driving of the first current source and forms a first voltage difference signal between the base and the emitter of the first triode;

[0019] The emitter of the second transistor is connected to the second current source, and the base of the second transistor is connected to the emitter of the first transistor, so that the second transistor operates under the driving of the second current source and the first voltage difference signal to form a second voltage difference signal between the base and the emitter of the second transistor to generate the first sensing signal.

[0020] Optionally, the first filtering circuit includes a filtering resistor and a filtering capacitor:

[0021] The first end of the filter resistor is connected to the emitter of the second transistor, and the second end of the filter resistor is connected to the input end of the analog-to-digital conversion circuit to perform DC filtering on the second voltage difference signal;

[0022] The first end of the filter capacitor is connected to the collector of the second transistor, and the second end of the filter capacitor is connected to the input end of the analog-to-digital conversion circuit to perform AC filtering on the second voltage difference signal.

[0023] Optionally, both the first transistor and the second transistor are bipolar junction transistors with a negative temperature coefficient, so that when the value of the first digital signal is less than the set first overheating threshold, it is determined that the driving chip is in an overheating state.

[0024] Optionally, the second temperature detection module is located at the periphery of the circuit substrate where the light emitter is located.

[0025] Optionally, the second temperature detection module includes a second thermistor circuit, a second filtering circuit, and a signal comparison circuit; the second thermistor circuit is used to sense the temperature of the light emitter to generate a second sensing signal, and the second filtering circuit is used to filter the second sensing signal; the signal comparison circuit is used to compare the filtered second sensing signal with the set second overheating threshold to generate a corresponding comparison result signal, and the comparison result signal is used to determine whether the light emitter is in an overheating state.

[0026] Optionally, the second thermal sensing circuit includes a thermistor, and the thermistor is connected to a third current source to sense the temperature of the light emitter to generate a second sensing signal.

[0027] Optionally, the signal comparison circuit has a first signal input terminal, a second signal input terminal, and an output terminal;

[0028] The second signal input terminal is connected to a reference signal source, and the reference signal source corresponds to the set second overheating threshold;

[0029] The first signal input terminal is used to input the filtered second sensing signal and compare it with the reference signal source to generate the comparison result signal;

[0030] The output end is used to output the comparison result signal.

[0031] Optionally, the thermistor is a thermistor with a negative temperature coefficient, so that when the value of the filtered second sensing signal is less than the reference signal source, the comparison result signal output by the output end is flipped from a high level to a low level, and it is determined that the optical transmitter is in an overheated state.

[0032] A method for detecting overheating of a time-of-flight ranging module, comprising:

[0033] The driver chip generates a driving signal;

[0034] The light emitter included in the light source is used to generate a light source signal according to the driving signal, and the optical device included in the light source generates a modulated light signal according to the light source signal, and the modulated light signal is used to determine the distance driving signal between the target object and the reference position;

[0035] A first temperature detection module detects the temperature of the driver chip to generate a first sensing signal, wherein the first sensing signal is used to compare with a set first overheating threshold to determine whether the driver chip is in an overheating state, wherein the first overheating threshold ranges from 85 degrees to 125 degrees;

[0036] The second temperature detection module detects the temperature of the light emitter to generate a second sensing signal, and the second sensing signal is used to compare with a set second overheating threshold to determine whether the light emitter is in an overheating state. The second overheating threshold ranges from 85 degrees to 110 degrees.

[0037] Optionally, the method further includes: when the driver chip is in an overheated state, controlling the driver chip to stop generating the drive signal, and / or, when the light emitter is in an overheated state, controlling the light emitter to stop generating the light source signal.

[0038] An electronic device comprising the time-of-flight ranging module according to any one of claims 1 to 12.

[0039] According to the time-of-flight ranging module, overheat detection method and electronic device provided in the embodiment of the present application, the temperature of the driver chip can be detected based on the first temperature detection module to generate a first sensing signal, and the first sensing signal can be compared with the set first overheat threshold to determine whether the driver chip is in an overheat state, and the first overheat threshold range is 85 degrees to 125 degrees, so as to ensure that the time-of-flight ranging module can perform corresponding processing according to whether overheating occurs. Furthermore, the temperature of the light emitter can be detected based on the second temperature detection module to generate a second sensing signal, and the second sensing signal can be compared with the set second overheat threshold to determine whether the light emitter is in an overheat state, and the second overheat threshold range is 85 degrees to 110 degrees, so as to ensure that the time-of-flight ranging module can perform corresponding processing according to whether overheating occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0041] Figure 1 Schematic diagram of the structure of a time-of-flight ranging module according to an embodiment of the present application;

[0042] Figure 2 Schematic diagram of the structure of another time-of-flight ranging module according to an embodiment of the present application;

[0043] Figure 3 Schematic diagram of the structure of another time-of-flight ranging module according to an embodiment of the present application;

[0044] Figure 4 This is a schematic diagram of the structure of the first temperature detection module in an embodiment of the present application;

[0045] Figure 5 This is a schematic diagram of the structure of the second temperature detection module in an embodiment of the present application;

[0046] Figure 6 A schematic diagram of the location of the thermistor in an embodiment of the present application;

[0047] Figure 7 This is a schematic diagram of determining the relationship between the temperature of the light emitter and the second sensing signal in a specific application scenario in an embodiment of the present application;

[0048] Figure 8 It is a schematic diagram of the principle of setting the temperature threshold when the light emitter is overheated based on the tolerance in an embodiment of the present application;

[0049] Fig. 9 The present invention is a flowchart of an overheat detection method for a time-of-flight ranging module according to an embodiment of the present application. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings. For ease of explanation, in the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application shown in the accompanying drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0051] It should be noted that, under the premise of no conflict, the various embodiments described in this application and / or the technical features in each embodiment can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the protection scope of this application.

[0052] It should be understood that the specific examples in the embodiments of the present application are only intended to help those skilled in the art to better understand the embodiments of the present application, rather than to limit the scope of the embodiments of the present application.

[0053] It should also be understood that in the various embodiments of the present application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0054] 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, and are not intended to limit the embodiments of the present application. For example, the singular forms "a", "above", and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0055] As used herein, terms such as "first," "second," and "third" describe various components, elements, regions, layers, and / or sections, but such components, elements, regions, layers, and / or sections should not be limited by such terms. Such terms may only be used to distinguish one component, element, region, layer, or section from another. Terms such as "first," "second," and "third" do not imply a sequence or order when used herein unless clearly indicated by the context.

[0056] Additionally, for ease of description, spatially relative terms such as "below," "lower," "above," "upper," and the like may be used herein to describe one component or member's relationship to another component or member illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted similarly.

[0057] In the process of implementing this application, the inventors found that the main reasons why the optical transmitter and driver chip overheated when the time-of-flight ranging module was working were as follows:

[0058] (1) For the driver chip, since a larger input signal is required when the driver chip generates a larger drive signal, the temperature of the driver chip will be too high, thus causing the driver chip to overheat;

[0059] (2) For the optical transmitter, when the optical transmitter generates a modulated optical signal with a large optical power, a large driving signal is required to drive it, which will cause the temperature of the optical transmitter to be too high, thereby causing the optical transmitter to overheat.

[0060] According to the time-of-flight ranging module, overheat detection method and electronic device provided in the embodiment of the present application, the temperature of the driver chip can be detected based on the first temperature detection module to generate a first sensing signal, and the first sensing signal can be compared with the set first overheat threshold to determine whether the driver chip is in an overheat state. The first overheat threshold range is 85 degrees to 125 degrees, so as to ensure that the time-of-flight ranging module can perform corresponding processing according to whether overheating occurs. Furthermore, the temperature of the light emitter can be detected based on the second temperature detection module to generate a second sensing signal, and the second sensing signal can be compared with the set second overheat threshold to determine whether the light emitter is in an overheat state. The second overheat threshold range is 85 degrees to 110 degrees, so as to ensure that the time-of-flight ranging module can perform corresponding processing according to whether overheating occurs.

[0061] The flight time difference ranging module of the embodiment of the present application can be installed in an electronic device, and the electronic device includes: any electronic device such as a portable terminal, an unmanned aerial vehicle, a tablet computer, etc., and the embodiment of the present application is not limited to this.

[0062] Figure 1 Schematic diagram of the structure of a time-of-flight ranging module according to an embodiment of the present application; Figure 1 As shown, it includes: a driving chip 101, a light source 102, a first temperature detection module 103A, and a second temperature detection module 103B. Among them:

[0063] The driving chip 101 is used to generate a driving signal. Specifically, in this embodiment, the driving chip 101 can generate a driving signal according to an input signal. For example, the driving signal is obtained by multiplying the input signal by a bias coefficient.

[0064] In this embodiment, the size of the input signal is determined according to the application scenario. Further, both the input signal and the drive signal can be current signals. Of course, here, only the current signal is used as an example to illustrate the input signal and the drive signal, and it does not limit the input signal and the drive signal to only be current signals.

[0065] The light source 102 includes a light emitter 112 and an optical device 122. The light emitter 112 is used to generate a light source signal according to a driving signal. The optical device 122 generates a modulated light signal according to the light source signal. The modulated light signal is used to determine the distance between the target object and the reference position. When the light source 102 is a flood light source, the optical device 122 is a light homogenizer; when the light source 102 is a point light source, the optical device 122 includes a lens group and a diffractive optical element.

[0066] Specifically, the modulated light signal illuminates the target and is reflected to form a reflected light signal, so that the time-of-flight ranging module determines the distance between the target and the reference position according to the flight time difference between the reflected light signal and the modulated light signal.

[0067] In this embodiment, the light emitter 112 is, for example, a vertical cavity surface light emitter VCSEL. Here, it should be noted that the vertical cavity surface light emitter VCSEL is only an example of the light emitter 112 and is not limited to only one. A person skilled in the art may use other forms of light emitters according to the requirements of the application scenario, as long as the distance between the target object and the reference position can be determined.

[0068] The first temperature detection module 103A is used to detect the temperature of the driver chip 101 to generate a first sensing signal, which is used to compare with a set first overheating threshold to determine whether the driver chip 101 is in an overheating state. The first overheating threshold ranges from 85 degrees to 125 degrees.

[0069] The second temperature detection module 103B is used to detect the temperature of the light emitter 112 to generate a second sensing signal, which is used to compare with a set second overheating threshold to determine whether the light emitter 112 is in an overheating state. The second overheating threshold ranges from 85 degrees to 110 degrees.

[0070] Optionally, the time-of-flight ranging module performs corresponding processing according to whether overheating occurs. For example, if the driver chip 101 is in an overheated state, the driver chip 101 stops generating a driving signal; if the light emitter 112 is in an overheated state, the light emitter 112 stops generating a light source signal.

[0071] Further, if only the optical emitter 112 is in an overheated state, when the temperature of the optical emitter 112 returns to normal, the driver chip 101 resumes operation to generate a drive signal, so that the optical emitter 112 resumes operation to generate a light source signal according to the drive signal. If only the driver chip 101 is in an overheated state, when the temperature of the driver chip 101 returns to normal, the driver chip 101 resumes operation to generate a drive signal, so that the optical emitter 112 continues to generate a light source signal according to the drive signal. If both the optical emitter 112 and the driver chip 101 are in an overheated state, when the temperatures of the optical emitter 112 and the driver chip 101 return to normal, the driver chip 101 resumes operation to generate a drive signal, so that the optical emitter 112 resumes operation to generate a light modulated light signal according to the light source signal.

[0072] Further, when the driver chip 101 stops generating the driving signal, the first temperature detection module 103A continuously monitors the temperature of the driver chip 101 and generates a first sensing signal, which is compared with the set first overheating threshold to determine that the temperature of the driver chip 101 returns to normal (i.e., lower than the temperature threshold when the light emitter 112 is overheated), so that the driver chip 101 resumes generating the driving signal. Here, in order to avoid frequently stopping and resuming the generation of the driving signal, a hysteresis threshold is set. When the temperature of the driver chip 101 is lower than the difference between the temperature threshold when the light emitter 112 is overheated and the hysteresis threshold, it is considered that the temperature of the driver chip 101 has returned to normal.

[0073] Similarly, when the light emitter 112 stops generating the light source signal, the second temperature detection module 103B continuously monitors the temperature of the light emitter 112 and generates a second sensing signal, and compares it with the set second overheating threshold to determine that the temperature of the light emitter 112 has returned to normal (i.e., lower than the temperature threshold when the light emitter 112 is overheated), so that the light emitter 112 resumes generating the modulated light signal. Here, in order to avoid frequently stopping and resuming the generation of the light source signal, another hysteresis threshold is set. When the temperature of the light emitter 112 is lower than the difference between the temperature threshold when the light emitter 112 is overheated and the hysteresis threshold, it is considered that the temperature of the light emitter 112 has returned to normal.

[0074] Optionally, in this embodiment, the driver chip 101 can be stopped from generating a driving signal by, for example, not providing an input signal for generating a driving signal to the driver chip 101. The light emitter 112 can be stopped from generating a light source signal by, for example, not providing a driving signal to the light emitter by the driver chip 101.

[0075] The specific implementation of making the driver chip 101 stop generating the driving signal and making the light emitter 112 stop generating the light source signal is only an example and is not a sole limitation. A person skilled in the art may use other methods to achieve it.

[0076] Figure 2 FIG. 2 is a schematic diagram of the structure of another time-of-flight ranging module according to an embodiment of the present application; Figure 2 As shown above Figure 1 The same includes: a driving chip 101, a light source 102, a first temperature detection module 103A, and a second temperature detection module 103B. In addition, the time-of-flight ranging module also includes: a photosensitive chip 104. The photosensitive chip 104 is used to control the driving chip to stop generating a driving signal when the driving chip 101 is in an overheated state, or to control the light emitter 112 to stop generating a light source signal when the light emitter 112 is in an overheated state.

[0077] Optionally, in this embodiment, the photosensitive chip 104 can determine whether the driving chip 101 is in an overheated state by comparing the first sensing signal with a set first overheating threshold. Further, when the driving chip 101 is in an overheated state, the photosensitive chip issues a control instruction to cause the driving chip 101 to stop generating a driving signal.

[0078] Optionally, in this embodiment, the photosensitive chip 104 can determine whether the light emitter is in an overheated state by comparing the second sensing signal with a set second overheat threshold. Further, when the light emitter is in an overheated state, the photosensitive chip issues a control instruction to cause the light emitter to stop generating a light source signal.

[0079] Figure 3 FIG. 2 is a schematic diagram of the structure of another time-of-flight ranging module according to an embodiment of the present application; Figure 3 As shown above Figure 1 The same as above, it includes: a driving chip 101, a light source 102, a first temperature detection module 103A, and a second temperature detection module 103B. Figure 1 The difference is that the first temperature detection module is also used to send the first sensing signal to the main control chip of the electronic device where the time-of-flight ranging module is located, so that when the driving chip is in an overheated state, the main control chip controls the driving chip to stop generating the driving signal; and / or, the second temperature detection module is also used to send the second sensing signal to the main control chip, so that when the light emitter is in an overheated state, the main control chip controls the light emitter to stop generating the light source signal.

[0080] Specifically, the main control chip compares the first sensing signal with a set first overheating threshold to determine whether the driver chip 101 is in an overheating state. Further, when the driver chip 101 is in an overheating state, the main control chip issues a control instruction to stop the driver chip 101 from generating a driving signal.

[0081] However, it should be noted that the above-mentioned comparison of the first sensing signal by the photosensitive chip or the main control chip with the set first overheating threshold to determine whether the driver chip 101 is in an overheating state, and when the driver chip 101 is in an overheating state, the photosensitive chip or the main control chip issues a control instruction to make the driver chip 101 stop generating a driving signal, is only an example and is not a unique limitation. In fact, for ordinary technicians in this field, according to the needs of the application scenario, other chips or circuits with data processing capabilities can also be selected to compare the first sensing signal with the set first overheating threshold to determine whether the driver chip 101 is in an overheating state, and when the driver chip 101 is in an overheating state, the photosensitive chip or the main control chip issues a control instruction to make the driver chip 101 stop generating a driving signal.

[0082] Similarly, the photosensitive chip or the main control chip may also compare the second sensing signal with a set second overheating threshold to determine whether the light emitter is in an overheating state.

[0083] Figure 4 Schematic diagram of the structure of the first temperature detection module of the embodiment of the present application; Figure 4 As shown, the first temperature detection module 103A includes a first thermistor circuit 113A, a first filter circuit 123A, and an analog-to-digital conversion circuit (also referred to as ADC in the figure) 133A. The first thermistor circuit 113A is used to sense the temperature of the driver chip 101 to generate a first sensing signal. The first filter circuit 123A is used to filter the first sensing signal. The analog-to-digital conversion circuit 133A is used to perform analog-to-digital conversion on the first sensing signal after filtering to obtain a first digital signal, so that the photosensitive chip or the main control chip compares the first digital signal with the set first overheating threshold to determine whether the driver chip 101 is in an overheating state, so that when it is determined that the driver chip 101 is in an overheating state, the driver chip 101 can be quickly stopped from generating a driving signal (or it is also referred to as powering off the driver chip 101).

[0084] In this embodiment, the set first overheat threshold is converted into a digital signal, and the main control chip or the photosensitive chip can directly compare the first digital signal with the set first overheat threshold to determine whether the driver chip 101 is in an overheat state. For example, if the first thermistor 113A is a thermistor with a negative temperature coefficient, the higher the temperature, the smaller the value of the first sensing signal, and when the value of the first digital signal is less than the set first overheat threshold, it is determined that the driver chip 101 is in an overheat state; if the first thermistor 113A is a thermistor with a positive temperature coefficient, the higher the temperature, the larger the value of the first sensing signal, and when the value of the first digital signal is greater than the set first overheat threshold, it is determined that the driver chip 101 is in an overheat state.

[0085] Alternatively, in another embodiment, if the set first overheating threshold is an analog signal, the first temperature detection module 103A includes the above-mentioned first thermistor circuit 113A and the first filtering circuit 123A, and the corresponding comparison result signal can be obtained by comparing the first sensing signal after filtering with the set first overheating threshold, and the comparison result signal is input to the main control chip or the photosensitive chip. If the main control chip or the photosensitive chip detects that the comparison result signal is flipped, it is determined whether the driving chip 101 is in an overheated state. For example, if the first thermistor 113A is a thermistor with a negative temperature coefficient, the higher the temperature, the smaller the value of the first sensing signal. When the value of the first sensing signal is less than the set first overheating threshold, the main control chip or the photosensitive chip detects that the comparison result signal is flipped from a high level to a low level, and the driver chip 101 is determined to be in an overheating state; if the first thermistor 113A is a thermistor with a positive temperature coefficient, the higher the temperature, the larger the value of the first sensing signal. When the value of the first sensing signal is greater than the set first overheating threshold, the main control chip or the photosensitive chip detects that the comparison result signal is flipped from a low level to a high level, and the driver chip 101 is determined to be in an overheating state.

[0086] Optionally, the first thermistor circuit 113A, the first filter circuit 123A, and the analog-to-digital conversion circuit 133A are all located on the same circuit board, for example.

[0087] Specifically, see Figure 4 As shown, the first thermistor circuit 113A includes a first transistor Q1 and a second transistor Q2, and the first filter circuit 123A includes a filter resistor R and a filter capacitor C.

[0088] Among them, for the first thermistor circuit 113A, the emitter of the first transistor Q1 is connected to the first current source I1, and the base and collector of the first transistor Q1 are both connected to the collector of the second transistor Q2, so that the first transistor Q1 operates under the drive of the first current source and forms a first voltage difference signal between the base and the emitter of the first transistor Q1; the emitter of the second transistor Q2 is connected to the second current source I2, and the base of the second transistor Q2 is connected to the emitter of the first transistor, so that the second transistor operates under the drive of the second current source and the first voltage difference signal to form a second voltage difference signal between the base and the emitter of the second transistor to generate a first sensing signal.

[0089] In this embodiment, since the temperature of the driver chip 101 will cause the change of the first voltage difference signal, and the first voltage difference signal is input to the base of the second transistor, which will cause the change of the second voltage difference signal, and at the same time, the temperature of the driver chip 101 will cause the change of the second voltage difference signal. Therefore, the temperature of the driver chip 101 can be accurately reflected by using the second voltage difference signal as the first sensing signal.

[0090] Optionally, in Figure 4 In the embodiment, the first transistor and the second transistor are both bipolar junction transistors with negative temperature coefficients, so that when the value of the first digital signal is less than a set first overheating threshold, it is determined that the driving chip 101 is in an overheating state.

[0091] In one application scenario, the first sensing signal V adc is a voltage signal. For a bipolar junction transistor with a negative temperature coefficient, the voltage difference between its base and emitter can be recorded as V BE , the relationship between it and temperature is as follows:

[0092]

[0093] In the above formula (1), K is the Boltzmann constant, T is the temperature of the transistor (corresponding to the temperature of the driver chip 101), ξ represents the parameter of mobility changing with temperature, Eg is the negative temperature coefficient of the bipolar junction transistor, which is about -1.5mV, then the electrical signal input to the analog-to-digital conversion circuit 133A is recorded as V adc , its size is determined according to the following formula (2):

[0094] V adc =2*V BE -1.5*T(2)

[0095] The input electrical signal V of the analog-to-digital conversion circuit 133A adc In fact, it is the first sensing signal, that is, the first sensing signal satisfies the above formula (2).

[0096] To this end, the analog-to-digital conversion circuit 133A converts the input electrical signal V adc The resolution is limited. Therefore, when designing the first temperature detection module 103A, the specifications of the first transistor and the second transistor, and the sizes of the first current source I1 and the second current source I2 are adjusted so that the dynamic range of the first sensing signal matches the resolution of the analog-to-digital conversion circuit 133A for the input electrical signal. For example, the dynamic range of the first sensing signal is smaller than the resolution of the analog-to-digital conversion circuit 133A for the input electrical signal, or is equal to the resolution of the analog-to-digital conversion circuit 133A for the input electrical signal, so that any temperature within the full temperature range of the driver chip 101 can be detected, thereby ensuring the accuracy of temperature detection.

[0097] Among them, for the first filtering circuit 123A, the first end of the filtering resistor R is connected to the emitter of the second triode, and the second end of the filtering resistor R is connected to the input end of the analog-to-digital conversion circuit 133A, so as to perform DC filtering processing on the second voltage difference signal; the first end of the filtering capacitor C is connected to the collector of the second triode, and the second end of the filtering capacitor C is connected to the input end of the analog-to-digital conversion circuit 133A, so as to perform AC filtering processing on the second voltage difference signal. Thus, the first filtering circuit 123A realizes DC filtering of the first sensing signal and also realizes AC filtering, thereby eliminating interference signals and improving the accuracy of reflecting the temperature of the driver chip 101 through the first sensing signal.

[0098] It should be noted that the first filter circuit 123A is described as including a filter resistor R and a filter capacitor C, which does not limit the first filter circuit 123A to only include a filter resistor R and a filter capacitor C. In fact, for ordinary technicians in this field, other forms of filter circuits can also be used.

[0099] Figure 5 Schematic diagram of the structure of the second temperature detection module of the embodiment of the present application; Figure 5 As shown, the second temperature detection module 103B includes a second thermistor circuit 113B, a second filter circuit 123B, and a signal comparison circuit 133B; the second thermistor circuit 113B is used to sense the temperature of the light emitter 112 to generate a second sensing signal, and the second filter circuit 123B is used to filter the second sensing signal; the signal comparison circuit 133B is used to compare the filtered second sensing signal with the set second overheating threshold to generate a corresponding comparison result signal, and the comparison result signal is used to determine whether the light emitter 112 is in an overheating state.

[0100] Optionally, Figure 5 In the embodiment, the second thermistor circuit 113B includes a thermistor R_ext, which is connected to a third current source I_ctrl to sense the temperature of the light emitter 112 to generate a second sensing signal. The third current source is a constant current source to provide a stable current signal as an excitation electrical signal, so that only the temperature of the light emitter 112 causes the second sensing signal to change. Specifically, the third current source can be provided by the driver chip 101.

[0101] Similar to the first filtering circuit described above, the second filtering circuit 123B also includes a filtering resistor R and a filtering capacitor C to implement DC filtering and AC filtering of the second sensing signal.

[0102] The signal comparison circuit 133B has a first signal input terminal Input1, a second signal input terminal Input2, and an output terminal Output. For the signal comparison circuit 133B, the second signal input terminal is connected to the reference signal source Vctrl, and the reference signal source corresponds to the temperature threshold when the optical transmitter 112 overheats; the first signal input terminal is used to input the second induction signal Vin after filtering processing and compare it with the reference signal source to generate a comparison result signal; the output terminal is used to output the comparison result signal. The signal comparison circuit 133B is, for example, a comparator. The reference signal source is provided by the driving chip 101, for example.

[0103] Optionally, in this embodiment, the thermistor is a thermistor with a negative temperature coefficient, so that when the value of the second induction signal after filtering processing is less than the reference signal source, the comparison result signal output by the output terminal flips from a high level to a low level, determining that the optical transmitter 112 is in an overheated state. Since for a thermistor with a negative temperature coefficient, the resistance value of the thermistor decreases as the temperature increases and will呈现 a negative exponential function form. Therefore, the higher the temperature, the smaller the resistance value, and correspondingly, the second induction signal after filtering processing will also become smaller. Therefore, when the temperature of the optical transmitter 112 is normal, the output terminal outputs a high level. When the value of the second induction signal after filtering processing is less than the reference signal source, the comparison result signal output by the output terminal flips to a low level. Therefore, it can be determined that the optical transmitter 112 is in an overheated state.

[0104] Specifically, there is the following mathematical relationship of formula (3) among the third current source I_ctrl, the reference signal source Vctrl, the second induction signal Vin, and the thermistor R_ext:

[0105] Vin = I_ctrl * R_ext (3)

[0106] Under normal circumstances, when the temperature of the optical transmitter 112 is normal, Vin > Vctrl, and the output terminal of the signal comparison circuit 133B outputs a high level. When the temperature of the optical transmitter 112 is too high, correspondingly Vin < Vctrl, and the output terminal of the signal comparison circuit 133B outputs a low level. The main control chip or the photosensitive chip continuously detects the output of the output terminal. When it is detected that the comparison result signal TMR_COMP_OUT flips from a high level to a low level, the driving chip 101 is stopped from generating a driving signal and not supplied to the optical transmitter 112.

[0107] Alternatively, if the thermistor is a thermistor with a positive temperature coefficient, when the value of the filtered second sensing signal is greater than the reference signal source, the comparison result signal outputted from the output terminal is flipped from a low level to a high level, and it is determined that the light emitter 112 is in an overheated state. In addition, the filtered second sensing signal can be input into an analog-to-digital conversion circuit 133A for analog-to-digital conversion to obtain a corresponding digital signal, and then the main control chip or the photosensitive chip confirms the overheating state according to the digital signal.

[0108] Optionally, the second temperature detection module 103B is located at the periphery of the circuit substrate where the light emitter 112 is located so that the second temperature detection module 103B is close to the light emitter 112 to accurately detect the temperature of the light emitter 112 to generate a second sensing signal. It should be noted here that the above-mentioned method of making the second temperature detection module 103B close to the light emitter 112 is only an example and is not a unique limitation. In fact, for ordinary technicians in this field, the second temperature detection module 103B can be set at any position according to the requirements of the application scenario, as long as the temperature of the light emitter 112 can be accurately detected to generate the second sensing signal.

[0109] Figure 6 Schematic diagram of the location of thermistor in the embodiment of the present application; Figure 6 As shown, the position of the thermistor in the second temperature detection module 103B on the time-of-flight ranging module is as close as possible to the light emitter 112. However, considering that the thermistor is set in the time-of-flight ranging module through a welding process, but the light emitter 112 (such as VCSEL) cannot withstand ordinary welding, and if the circuit substrate 105 where the light emitter 112 is located is a ceramic substrate, the thermistor is placed on the periphery of the ceramic substrate, such as Figure 6 As shown, the light emitter is placed at one of the three sides that are not close to the driving chip 101 .

[0110] Alternatively, in another embodiment, the driving signal may be optically turned off so that the light emitter 112 no longer receives the driving signal.

[0111] Figure 7 This is a schematic diagram of determining the relationship between the temperature of the light emitter and the second sensing signal in a specific application scenario in an embodiment of the present application. Figure 8 The schematic diagram is a principle diagram of setting the temperature threshold of the light emitter when it is overheated based on the tolerance in the embodiment of the present application. In this application scenario, the thermistor is still taken as an example of a thermistor with a negative temperature coefficient.

[0112] In circuit design, in order to take into account the judgment of overheating state and support the normal operation of the flight time difference ranging module, on the one hand, considering the temperature resistance requirements of various structural parts in the flight time difference ranging module, it is necessary to ensure that the thermal damage temperature of each structural part is the lowest. For example, the lens plastic in the flight time difference ranging module will deform at a temperature higher than 110°C. Therefore, the temperature threshold of the light emitter 112 when it is overheated is preferably lower than 110°C. In addition, considering that the normal operation of the flight time difference ranging module should be supported, the average transmission power of the light emitter 112 should have sufficient strength. For this reason, the flight time difference ranging module as a whole will have a certain temperature rise. The stronger the average transmission power, the greater the temperature rise of the module itself. For this reason, if the temperature rise is around 20°C, to ensure that the flight time difference ranging module can work normally at an ambient temperature of 60°C, the temperature threshold of the light emitter 112 when it is overheated should be higher than 85°C. Based on this, in theory, assuming that the temperature of the light emitter 112 exceeds 93°C, the light emitter 112 is in an overheated state; at this time, theoretically, the reference signal source corresponding to 93°C is approximately 0.29V. Due to the temperature of the light emitter 112, the second sensing signal is smaller. Therefore, when the value of the second sensing signal is less than 0.29V, the light emitter 112 is in an overheated state.

[0113] In fact, taking into account factors such as tolerance of the third current source and the reference signal source, the third current source will have upper and lower limits based on its nominal value (also called theoretical value), and the reference signal source will have upper and lower limits (also called maximum value and minimum value) based on its nominal value. Therefore, it can be determined that when the optical emitter 112 is overheated, there will be upper and lower limits (respectively, the maximum temperature threshold value and the maximum temperature threshold value) based on its nominal value (also called theoretical value). By extension, any temperature threshold within the range limited by the upper and lower temperature limits can be selected as the temperature threshold when the optical emitter 112 is overheated.

[0114] At the same time, considering that the resistance value of a compatible thermistor is between 10 kΩ and 100 kΩ, the third current source and the reference signal source can be adjusted so that the variation range of the second sensing signal is within the central range of the power domain of the driver chip 101; at the same time, considering the temperature range that the resistance value of the compatible thermistor can match, when adjusting the reference signal source, its variation range is preferably located at a relatively central position within the variation range of the second sensing signal.

[0115] Alternatively, in other embodiments, the second temperature detection module 103B may be implemented with reference to the structure of the first temperature detection module 103A described above.

[0116] Optionally, when the optical transmitter 112 is in an overheated state, or the driver chip 101 is in an overheated state, a notification of abnormal operation of the time-of-flight ranging module is generated, and an upper layer application of the relevant time-of-flight ranging module is suspended.

[0117] Fig. 9 The flowchart of an overheat detection method of a time-of-flight ranging module in an embodiment of the present application is shown; the method is applied to any time-of-flight ranging module in an embodiment of the present application, the time-of-flight ranging module includes a driver chip, a light transmitter, a first temperature detection module, and a second temperature detection module, and the method includes:

[0118] S901, the driving chip generates a driving signal;

[0119] S902, the light emitter included in the light source is used to generate a light source signal according to the driving signal, and the optical device included in the light source generates a modulated light signal according to the light source signal, and the modulated light signal is used to determine the distance driving signal between the target object and the reference position;

[0120] S903A, a first temperature detection module detects the temperature of the driver chip to generate a first sensing signal, and the first sensing signal is used to compare with a set first overheating threshold to determine whether the driver chip is in an overheating state;

[0121] In this embodiment, the first overheating threshold ranges from 85 degrees to 125 degrees;

[0122] S903B, the second temperature detection module detects the temperature of the light emitter to generate a second sensing signal, and the second sensing signal is used to compare with a set second overheating threshold to determine whether the light emitter is in an overheating state;

[0123] In this embodiment, the second overheating threshold ranges from 85 degrees to 110 degrees.

[0124] Here, it should be noted that, in other embodiments, the above-mentioned step S903A and step S903B may be executed in parallel, or step S903A may be executed after step S903B.

[0125] Optionally, in one embodiment, the method further includes: when the driver chip is in an overheated state, controlling the driver chip to stop generating a driving signal, and / or, when the light emitter is in an overheated state, controlling the light emitter to stop generating a light source signal.

[0126] It should be pointed out that, according to the needs of implementation, the various components / steps described in the embodiments of the present application can be split into more components / steps, or two or more components / steps or partial operations of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of the present application.

[0127] The above implementation methods are only used to illustrate the embodiments of the present application, and are not limitations on the embodiments of the present application. Ordinary technicians in the relevant technical field can 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. The scope of patent protection of the embodiments of the present application should be limited by the claims.

Claims

1. A time-of-flight ranging module, characterized in that: include: A driving chip, used for generating a driving signal; A light source, comprising a light emitter and an optical device, wherein the light emitter is used to generate a light source signal according to the driving signal, and the optical device generates a modulated light signal according to the light source signal, wherein the modulated light signal is used to determine the distance between the target object and the reference position; A first temperature detection module, used for detecting the temperature of the driver chip to generate a first sensing signal, the first sensing signal is used for comparing with a set first overheating threshold to determine whether the driver chip is in an overheating state, the first overheating threshold range is 85 degrees to 125 degrees; a second temperature detection module, used for detecting the temperature of the light emitter to generate a second sensing signal, the second sensing signal is used for comparing with a set second overheating threshold to determine whether the light emitter is in an overheating state, the second overheating threshold range is 85 degrees to 110 degrees; Among them, the first temperature detection module includes a first thermistor circuit, and the first thermistor circuit includes a first transistor and a second transistor: the first transistor works under the drive of a first current source and forms a first voltage difference signal between the base and the emitter of the first transistor; the second transistor works under the drive of a second current source and the first voltage difference signal to form a second voltage difference signal between the base and the emitter of the second transistor to generate the first sensing signal.

2. The time-of-flight ranging module according to claim 1, characterized in that: Also includes: Photosensitive chip, The photosensitive chip is used to control the driving chip to stop generating the driving signal when the driving chip is in an overheated state, or to control the light emitter to stop generating the light source signal when the light emitter is in an overheated state.

3. The time-of-flight ranging module according to claim 1, characterized in that: The first temperature detection module is also used to send the first sensing signal to the main control chip of the electronic device where the time-of-flight ranging module is located, so that when the driving chip is in an overheated state, the main control chip controls the driving chip to stop generating the driving signal; and / or, the second temperature detection module is also used to send the second sensing signal to the main control chip, so that when the light emitter is in an overheated state, the main control chip controls the light emitter to stop generating the light source signal.

4. The time-of-flight ranging module according to claim 1, characterized in that: The first temperature detection module also includes a first filtering circuit and an analog-to-digital conversion circuit. The first filtering circuit is used to filter the first sensing signal; the analog-to-digital conversion circuit is used to perform analog-to-digital conversion on the filtered first sensing signal to obtain a first digital signal, which is compared with the set first overheating threshold to determine whether the driver chip is in an overheating state.

5. The time-of-flight ranging module according to claim 4, characterized in that: The emitter of the first triode is connected to the first current source, and the base and collector of the first triode are both connected to the collector of the second triode; The emitter of the second transistor is connected to the second current source, and the base of the second transistor is connected to the emitter of the first transistor.

6. The time-of-flight ranging module according to claim 5, characterized in that: The first filter circuit includes a filter resistor and a filter capacitor: The first end of the filter resistor is connected to the emitter of the second transistor, and the second end of the filter resistor is connected to the input end of the analog-to-digital conversion circuit to perform DC filtering on the second voltage difference signal; The first end of the filter capacitor is connected to the collector of the second transistor, and the second end of the filter capacitor is connected to the input end of the analog-to-digital conversion circuit to perform AC filtering on the second voltage difference signal.

7. The time-of-flight ranging module according to claim 6, characterized in that: The first transistor and the second transistor are both bipolar junction transistors with negative temperature coefficients, so that when the value of the first digital signal is less than the set first overheating threshold, it is determined that the driving chip is in an overheating state.

8. The time-of-flight ranging module according to claim 1, characterized in that: The second temperature detection module is located outside the circuit substrate where the light emitter is located.

9. The time-of-flight ranging module according to claim 1, characterized in that: The second temperature detection module includes a second thermistor circuit, a second filtering circuit, and a signal comparison circuit; the second thermistor circuit is used to sense the temperature of the light emitter to generate a second sensing signal, and the second filtering circuit is used to filter the second sensing signal; the signal comparison circuit is used to compare the filtered second sensing signal with the set second overheating threshold to generate a corresponding comparison result signal, and the comparison result signal is used to determine whether the light emitter is in an overheating state.

10. The time-of-flight ranging module according to claim 9, characterized in that: The second thermal sensing circuit includes a thermistor connected to a third current source to sense the temperature of the light emitter to generate a second sensing signal.

11. The time-of-flight ranging module according to claim 10, characterized in that: The signal comparison circuit has a first signal input terminal, a second signal input terminal, and an output terminal; The second signal input terminal is connected to a reference signal source, and the reference signal source corresponds to the set second overheating threshold; The first signal input terminal is used to input the filtered second sensing signal and compare it with the reference signal source to generate the comparison result signal; The output end is used to output the comparison result signal.

12. The time-of-flight ranging module according to claim 11, characterized in that: The thermistor is a thermistor with a negative temperature coefficient, so that when the value of the filtered second sensing signal is less than the reference signal source, the comparison result signal output by the output end is flipped from a high level to a low level, and it is determined that the optical transmitter is in an overheated state.

13. A method for detecting overheating of a time-of-flight ranging module, characterized in that: include: The driver chip generates a driving signal; The light emitter included in the light source is used to generate a light source signal according to the driving signal, and the optical device included in the light source generates a modulated light signal according to the light source signal, and the modulated light signal is used to determine the distance driving signal between the target object and the reference position; A first temperature detection module detects the temperature of the driver chip to generate a first sensing signal, wherein the first sensing signal is used to compare with a set first overheating threshold to determine whether the driver chip is in an overheating state, wherein the first overheating threshold ranges from 85 degrees to 125 degrees; The second temperature detection module detects the temperature of the light emitter to generate a second sensing signal, and the second sensing signal is used to compare with a set second overheating threshold to determine whether the light emitter is in an overheating state, and the second overheating threshold ranges from 85 degrees to 110 degrees; Among them, the first temperature detection module includes a first thermistor circuit, and the first thermistor circuit includes a first transistor and a second transistor: the first transistor works under the drive of a first current source and forms a first voltage difference signal between the base and the emitter of the first transistor; the second transistor works under the drive of a second current source and the first voltage difference signal to form a second voltage difference signal between the base and the emitter of the second transistor to generate the first sensing signal.

14. The method according to claim 13, characterized in that The method further includes: when the driver chip is in an overheated state, controlling the driver chip to stop generating the drive signal, and / or, when the light emitter is in an overheated state, controlling the light emitter to stop generating the light source signal.

15. An electronic device comprising the time-of-flight ranging module according to any one of claims 1 to 12.

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