Vehicle-mounted electronic outside rear-view mirror and temperature protection circuit thereof

Abstract

The embodiment of the utility model provides a vehicle-mounted electronic outside rear-view mirror and a temperature protection circuit thereof. The temperature protection circuit comprises a high temperature detection module; a low temperature detection module; the main control module is used for calculating a corresponding first detection temperature and a corresponding second detection temperature according to the first detection voltage and the second detection voltage, and outputting a PWM signal with a corresponding duty ratio according to the first detection temperature when the first detection temperature is greater than or equal to a preset high-temperature threshold value; when the second detection temperature is smaller than or equal to a preset low-temperature threshold value, a PWM signal with the corresponding duty ratio is output according to the second detection temperature; and the backlight power supply driving module is connected with the output end of the main control module and the display screen module, and is used for outputting a corresponding driving current with a preset size to the display screen module according to the duty ratio of the PWM signal output by the main control module and the third data table. According to the embodiment, accurate temperature protection control on the display screen module can be realized.

Description

TECHNICAL FIELD

[0001] The embodiment of the utility model relates to the technical field of vehicle-mounted display circuit, especially relates to a vehicle-mounted electronic outside rearview mirror and temperature protection circuit thereof. BACKGROUND

[0002] At present, the vehicle-mounted electronic outside rearview mirror is usually provided with a temperature protection circuit to ensure that the display screen module of the vehicle-mounted electronic outside rearview mirror can normally and stably work when the ambient temperature is too high or too low.

[0003] The temperature protection circuit of the existing vehicle-mounted electronic outside rearview mirror mainly comprises: a temperature detection module provided with a thermistor and a main control chip connected to a sampling point of the temperature detection module, the main control chip collects the actual detection voltage value output by the temperature detection module from the sampling point and adjusts the duty cycle of the PWM dimming signal output according to the actual detection voltage value, and then drives the drive current of the backlight unit of the display screen module, finally adjusts the working brightness of the display screen of the display screen module, increases the luminous brightness to realize heating in a low-temperature environment, and reduces the luminous brightness to realize cooling in a high-temperature environment.

[0004] However, the inventor found in the specific implementation that only one temperature detection module is arranged in the above-mentioned circuit, and the ambient temperature variation range of the vehicle-mounted electronic outside rearview mirror is relatively large (for example: -40 DEG C ~ 80 DEG C), and the resistance variation range of the thermistor adapted thereto is also relatively very large, so that when the high and low temperature detection is realized only by relying on a single temperature detection module, the detection accuracy of the ambient temperature is relatively low, and accurate temperature protection control of the display screen module cannot be realized. UTILITY MODEL CONTENTS

[0005] The technical problem to be solved by the embodiment of the utility model lies in providing a temperature protection circuit of a vehicle-mounted electronic outside rearview mirror, which can realize accurate temperature protection control of a display screen module.

[0006] The further technical problem to be solved by the embodiment of the utility model lies in providing a vehicle-mounted electronic outside rearview mirror, which can realize accurate temperature protection control of a display screen module.

[0007] In order to solve the above-mentioned technical problem, the embodiment of the utility model provides the following technical scheme: a temperature protection circuit of a vehicle-mounted electronic outside rearview mirror, which is connected with a display screen module of the vehicle-mounted electronic outside rearview mirror, comprising:

[0008] The high-temperature detection module comprises a first power supply, a first sampling resistor R1, a first sampling capacitor C1 and a first thermistor, wherein the first power supply, the first sampling resistor R1 and the first sampling capacitor C1 are connected to a ground terminal in sequence, and the first thermistor is connected in parallel with the first sampling capacitor C1.

[0009] The low-temperature detection module comprises a second power supply, a second sampling resistor R1, a second sampling capacitor C1 and a second thermistor, wherein the second power supply, the second sampling resistor R1 and the second sampling capacitor C1 are connected in series and then connected to a ground terminal, the second thermistor is connected in parallel with the second sampling capacitor C1, the resistance value of the first sampling resistor R1 is different from the resistance value of the second sampling resistor R2, the circuit parameters of the first power supply and the second power supply are the same, the first thermistor and the second thermistor are the same type of thermistor and generate the same detection current based on the same ambient temperature around the vehicle-mounted electronic outside rearview mirror;

[0010] The main control module comprises two input terminals, a first sampling point and a second sampling point, and a first detection voltage and a second detection voltage, wherein the two input terminals of the main control module are connected to the first sampling point on the line between the first sampling capacitor C1 and the first sampling resistor R1 and the second sampling point on the line between the second sampling capacitor C1 and the second sampling resistor R2, respectively, to obtain the first detection voltage and the second detection voltage at the first sampling point and the second sampling point, respectively, the main control module is built-in with a first data table reflecting the corresponding relationship between the first detection temperature and the duty cycle of the PWM signal and a second data table reflecting the corresponding relationship between the second detection temperature and the duty cycle of the PWM signal, the main control module is used to calculate the corresponding first detection temperature and second detection temperature according to the first detection voltage and the second detection voltage, determine and sequentially output the PWM signal with the corresponding duty cycle according to the first detection temperature and the first data table when the first detection temperature is greater than or equal to a preset high-temperature threshold, and determine and sequentially output the PWM signal with the corresponding duty cycle according to the second detection temperature and the second data table when the second detection temperature is less than or equal to a preset low-temperature threshold; and

[0011] The backlight power supply driving module is connected to the output terminal of the main control module and the display screen module, is built-in with a third data table reflecting the corresponding relationship between the duty cycle of the PWM signal and the driving current, and is used to determine and sequentially output the driving current with the corresponding predetermined size to the display screen module according to the duty cycle of the PWM signal output by the main control module and the third data table.

[0012] Further, the main control module comprises:

[0013] The high-temperature sampling unit is connected to the first sampling point on the line between the first sampling capacitor C1 and the first sampling resistor R1, is used to obtain the first detection voltage at the first sampling point and calculate the corresponding first detection temperature according to the first detection voltage;

[0014] The low-temperature sampling unit is connected with a second sampling point on a line between the second sampling capacitor C1 and the second sampling resistor R1, and is used for obtaining a second detection voltage at the second sampling point and calculating a corresponding second detection temperature according to the second detection voltage;

[0015] The storage unit is used for storing the first data table, the second data table, a preset high-temperature threshold value and a preset low-temperature threshold value.

[0016] The comparison unit is connected with the high-temperature sampling unit, the low-temperature sampling unit and the storage unit respectively, and is used for comparing the first detection temperature with the preset high-temperature threshold value and comparing the second detection temperature with the preset low-temperature threshold value, outputting a high-temperature signal when the first detection temperature is greater than or equal to the preset high-temperature threshold value, and outputting a low-temperature signal when the second detection temperature is less than or equal to the preset low-temperature threshold value.

[0017] The PWM output unit is connected with the high-temperature sampling unit, the low-temperature sampling unit, the comparison unit and the storage unit and externally connected with the backlight power supply driving module, and is used for generating and outputting a first PWM signal with a corresponding duty ratio according to the first detection temperature and the first data table when the high-temperature signal is received, and generating and outputting a second PWM signal with a corresponding duty ratio according to the second detection temperature and the second data table when the low-temperature signal is received.

[0018] Further, the first thermistor and the second thermistor are both NTC thermistors, and the resistance value of the first sampling resistor R1 is less than the resistance value of the second sampling resistor R2.

[0019] Further, the temperature protection circuit further comprises:

[0020] The display screen image driving module is connected with the main control module and the display screen module respectively, and is used for driving the display screen module to display preset high-temperature early warning information when the main control module determines that the first detection temperature is greater than or equal to the preset high-temperature threshold value, and driving the display screen module to display preset low-temperature early warning information when the main control module determines that the second detection temperature is less than or equal to the preset low-temperature threshold value.

[0021] On the other hand, in order to solve the above-mentioned further technical problems, the utility model embodiment further provides the following technical scheme: a vehicle-mounted electronic outside rearview mirror, comprising a first camera and a second camera arranged on two sides of an outside of a motor vehicle, a display screen module installed in a cockpit of the motor vehicle and connected with the first camera and the second camera to display a shooting picture of the first camera and the second camera, and a temperature protection circuit connected with the display screen module, wherein the temperature protection circuit is the temperature protection circuit according to any one of the above-mentioned embodiments.

[0022] Further, the display screen module comprises:

[0023] a main display screen and a sub-display screen respectively installed at a driver seat side and a front passenger seat side of the vehicle and respectively connected with the first camera and the second camera to display the shooting pictures of the first camera and the second camera respectively; and

[0024] a main backlight unit and a sub-backlight unit respectively integrated in the main display screen and the sub-display screen to drive the main display screen and the sub-display screen to display;

[0025] The temperature protection circuit is provided with two backlight power supply driving modules respectively connected with the main backlight unit and the sub-backlight unit.

[0026] Further, the first thermistor is integrated in the main display screen, and the second thermistor is integrated in the sub-display screen.

[0027] After the above technical solution is adopted, the utility model embodiment has at least the following beneficial effects: the utility model embodiment is provided with a high-temperature detection module and a low-temperature detection module respectively, the high-temperature detection module and the low-temperature detection module generate detection currents of the same value based on the same ambient temperature around the electronic rearview mirror through a first thermistor and a second thermistor respectively, according to Ohm's law, since the resistance values of the first sampling resistor R1 and the second sampling resistor R2 are different and the circuit parameters of the first power supply and the second power supply are the same, the generated first detection voltage and second detection voltage are different, after the main control module obtains the first detection voltage and the second detection voltage, the first detection temperature and the second detection temperature are calculated correspondingly through the first detection voltage and the second detection voltage, on the one hand, when the ambient temperature is relatively high and the first detection temperature is greater than or equal to the preset high-temperature threshold value of the main control module, the corresponding duty ratio PWM signal is determined and outputted in turn according to the first detection voltage and the first data table at this time, and the output of the PWM dimming signal is realized; on the other hand, when the ambient brightness is relatively low and the second detection temperature is less than or equal to the preset low-temperature threshold value of the main control module, the corresponding duty ratio PWM signal is determined and outputted in turn according to the second detection voltage and the second data table, and the output of the PWM dimming signal is also realized; finally, the backlight power supply driving module outputs a driving current according to the duty ratio of the PWM signal to realize the dimming control of the display screen module, the applicable ambient brightness change range is wide, and the high-temperature detection module and the low-temperature detection module detect high temperature and low temperature respectively, so that the brightness of the display screen module is reduced and the brightness of the display screen module is improved correspondingly, and the display effect of the display screen module at high temperature and low temperature is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1The utility model discloses a circuit principle block diagram of one optional embodiment of vehicle-mounted electronic outside rearview mirror. DETAILED DESCRIPTION

[0029] The application will be described in further detail below in connection with the drawings and specific embodiments. It should be understood that the following illustrative embodiments and descriptions are only used to explain the utility model and are not as the limitation of the utility model, and in the case of no conflict, the embodiments in the application and the features in the embodiments can be combined with each other.

[0030] As Figure 1 The utility model discloses one optional embodiment of vehicle-mounted electronic outside rearview mirror temperature protection circuit 1 provides a kind of, and vehicle-mounted electronic outside rearview mirror's display screen module 3 is connected, comprising:

[0031] High temperature detection module 10 includes first power supply 101, first sampling resistor R1, first sampling capacitor C1 and first thermistor 103, wherein the first power supply 101, first sampling resistor R1, first sampling capacitor C1 are connected to ground in series, the first thermistor 103 is parallel with the first sampling capacitor C1;

[0032] Low temperature detection module 12 includes second power supply 121, second sampling resistor R1, second sampling capacitor C1 and second thermistor 123, wherein the second power supply 121, second sampling resistor R1, second sampling capacitor C1 are connected to ground in series, the second thermistor 123 is parallel with the second sampling capacitor C1, the resistance value of the first sampling resistor R1 is different from the resistance value of the second sampling resistor R2, the circuit parameter of the first power supply 101 and the second power supply 121 is same, the first thermistor 103 and second thermistor 123 are same type thermosensitive element and based on the same ambient temperature of vehicle-mounted electronic outside rearview mirror around simultaneously produce same detection current;

[0033] A main control module 14, two inputs of the main control module 14 are connected to a first sampling point A on a line between the first sampling capacitor C1 and the first sampling resistor R1 and a second sampling point B on a line between the second sampling capacitor C1 and the second sampling resistor R2 respectively to obtain a first detection voltage and a second detection voltage at the first sampling point A and the second sampling point B respectively, the main control module 14 is built-in with a first data table reflecting a corresponding relationship between a first detection temperature and a duty ratio of a PWM signal and a second data table reflecting a corresponding relationship between a second detection temperature and a duty ratio of a PWM signal, the main control module 14 is used to obtain a corresponding first detection temperature and a second detection temperature according to the first detection voltage and the second detection voltage, when the first detection temperature is greater than or equal to a preset high temperature threshold, a PWM signal with a corresponding duty ratio is determined and output in turn according to the first detection temperature and the first data table, and when the second detection temperature is less than or equal to a preset low temperature threshold, a PWM signal with a corresponding duty ratio is determined and output in turn according to the second detection temperature and the second data table; and

[0034] A backlight power supply driving module 16, connected to an output end of the main control module 14 and the display screen module 3, built-in with a third data table reflecting a corresponding relationship between a duty ratio of a PWM signal and a driving current, used to determine and output a driving current with a corresponding predetermined size to the display screen module 3 in turn according to a duty ratio of a PWM signal output by the main control module 14 and the third data table.

[0035] The utility model discloses the embodiment sets up high temperature detection module 10 and low temperature detection module 12 respectively, and high temperature detection module 10 and low temperature detection module 12 respectively produce the detection current of same value based on the same ambient temperature around electronic rearview mirror simultaneously through first thermistor 103 and second thermistor 123, according to Ohm's law, because the resistance value of first sampling resistance R1 is different with the resistance value of second sampling resistance R2 and the circuit parameter of first power supply 101 and second power supply 121 is same, therefore, the first detection voltage and second detection voltage corresponding generation are different, further, after the first detection voltage and second detection voltage are acquired by main control module 14, the first detection temperature and second detection temperature are calculated corresponding through the first detection voltage and second detection voltage, on one hand, when the ambient temperature is relatively higher and makes the first detection temperature greater than or equal to the preset high temperature threshold value of main control module 14, then according to the first detection voltage and first data table, the PWM signal of corresponding duty ratio is determined and is outputted in turn, and the output of PWM dimming signal is realized, on the other hand, when the ambient brightness is relatively lower and makes the second detection temperature less than or equal to the preset low temperature threshold value of main control module 14, then according to the second detection voltage and second data table, the PWM signal of corresponding duty ratio is determined and is outputted in turn, and the output of PWM dimming signal is also realized, finally, the driving current is outputted according to the duty ratio of PWM signal by backlight power drive module 16, realizes the dimming control to display screen module 3, and the applicable ambient brightness change range is wide, and high temperature detection module 10 and low temperature detection module 12 detect high temperature and low temperature respectively, thereby corresponding control display screen module 3 reduces the brightness and promotes the brightness, guarantees the display effect of display screen module 3 at high temperature and low temperature.

[0036] In the specific implementation, it can be understood that the circuit parameters of the first power supply 101 and the second power supply 121 are the same, which means that the output voltages of the two are the same, both being 3.3V; the first thermistor 103 and the second thermistor 123 have the same characteristic of resistance value change with temperature change.

[0037] In an optional embodiment of the utility model, as shown in the figure, Figure 1 The main control module 14 comprises:

[0038] The high-temperature sampling unit 141 is connected to the first sampling point A on the line between the first sampling capacitor C1 and the first sampling resistor R1, and is used to obtain the first detection voltage at the first sampling point A and calculate the corresponding first detection temperature according to the first detection voltage;

[0039] The low-temperature sampling unit 143 is connected to the second sampling point B on the line between the second sampling capacitor C1 and the second sampling resistor R1, and is used to obtain the second detection voltage at the second sampling point B and calculate the corresponding second detection temperature according to the second detection voltage;

[0040] a storage unit 145, configured to store the first data table, the second data table, a preset high-temperature threshold and a preset low-temperature threshold;

[0041] a comparison unit 147, connected with the high-temperature sampling unit 141, the low-temperature sampling unit 143 and the storage unit 145 respectively, configured to compare the first detection temperature with the preset high-temperature threshold and compare the second detection temperature with the preset low-temperature threshold, output a high-temperature signal when the first detection temperature is greater than or equal to the preset high-temperature threshold, and output a low-temperature signal when the second detection temperature is less than or equal to the preset low-temperature threshold; and

[0042] a PWM output unit 149, connected with the high-temperature sampling unit 141, the low-temperature sampling unit 143, the comparison unit 147 and the storage unit 145 and externally connected with the backlight power driving module 16, configured to generate and output a first PWM signal with a corresponding duty ratio according to the first detection temperature and the first data table when the high-temperature signal is received, and generate and output a second PWM signal with a corresponding duty ratio according to the second detection temperature and the second data table when the low-temperature signal is received.

[0043] In the embodiment, the first detection voltage and the second detection voltage are obtained by the high-temperature sampling unit 141 and the low-temperature sampling unit 143 respectively, and the first detection temperature and the second detection temperature are calculated, then the comparison unit 147 performs corresponding data comparison to determine whether the ambient temperature is in a preset high-temperature interval or a low-temperature interval, and finally the PWM output unit 149 outputs different PWM signals according to the high-temperature signal and the low-temperature signal, so as to realize the output of the PWM dimming signal, and the data processing process is simpler and the processing efficiency is relatively higher.

[0044] As shown in the following table, the first detection temperature T1 in the first data table of an optional embodiment of the present application and the display brightness of the display screen module 3 are shown in the following table.

[0045]

[0046] As shown in the following table, the second detection temperature T2 in the second data table of an optional embodiment of the present application and the display brightness of the display screen module 3 are shown in the following table.

[0047]

[0048] In an optional embodiment of the utility model, the first thermistor 103 and the second thermistor 123 are both NTC thermistors, and the resistance value of the first sampling resistor R1 is smaller than the resistance value of the second sampling resistor R2. In this embodiment, the NTC thermistor has a resistance value that decreases with the increase of temperature, so when the ambient temperature is high, the resistance value is small, and the voltage across the two ends is large, and the first sampling resistor R1 has a small resistance value (for example, 1.5 kΩ), and when the ambient temperature is low, the resistance value is large, and the voltage across the two ends is small, and the second sampling resistor R2 has a large resistance value (for example, 47 kΩ), so that the first detection voltage and the second detection voltage obtained by the main control module 14 at the corresponding ambient temperature are both relatively large, thereby avoiding too small values and affecting the calculation accuracy.

[0049] In an optional embodiment of the utility model, as shown in Figure 1 The temperature protection circuit 1 further comprises:

[0050] The display screen image driving module 18 is connected with the main control module 14 and the display screen module 3 respectively, and is used for driving the display screen module 3 to display preset high-temperature warning information when the main control module 14 determines that the first detection temperature is greater than or equal to the preset high-temperature threshold, and driving the display screen module 3 to display preset low-temperature warning information when the main control module 14 determines that the second detection temperature is less than or equal to the preset low-temperature threshold. In this embodiment, when the low-temperature or high-temperature condition occurs, the main control module 14 can also drive the display screen module 3 to display the corresponding low-temperature warning information and high-temperature warning information through the display screen image driving module 18, so as to prompt the driver to take corresponding measures (for example, starting the vehicle-mounted air conditioner to realize temperature rise or temperature drop, etc.) to ensure the work of the display screen module 3.

[0051] On the other hand, as shown in Figure 1 The utility model discloses an electronic outside rearview mirror, which comprises a first camera and a second camera, a display screen module and a temperature protection circuit.

[0052] In an optional embodiment of the utility model, as shown in Figure 1 The display screen module 3 comprises:

[0053] a main display screen 30 and a sub-display screen 32 respectively installed on the driver's side and the co-driver's side of the vehicle and respectively connected with the first camera 5 and the second camera 7 to display the shooting pictures of the first camera 5 and the second camera 7 respectively; and

[0054] a main backlight unit 34 and a sub-backlight unit 36 respectively integrated in the main display screen 30 and the sub-display screen 32 to drive the main display screen 30 and the sub-display screen 32 to display;

[0055] The temperature protection circuit 1 is provided with the backlight power supply driving module 16 connected with the main backlight unit 34 and the sub-backlight unit 36 respectively.

[0056] In the embodiment, the display screen module 3 comprises the main display screen 30 and the sub-display screen 32 respectively installed on the driver's side and the co-driver's side of the vehicle, and different display screens display different camera image information, which is convenient for the driver to view. Specifically, the display screen image driving module 18 usually drives the main display screen 30 to display the low temperature warning information and the high temperature warning information.

[0057] In an optional embodiment of the utility model, the first thermistor 103 is integrated in the main display screen 30, and the second thermistor 123 is integrated in the sub-display screen 32. In the embodiment, the first thermistor 103 is integrated in the main display screen 30, and the second thermistor 123 is integrated in the sub-display screen 32, which is convenient for the thermistor to accurately detect the working temperature of the corresponding display screen and can improve the control accuracy.

[0058] The embodiments of the utility model are described above in combination with the drawings, but the utility model is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are only illustrative but not restrictive, and the ordinary skilled in the art can make many forms under the inspiration of the utility model without departing from the purpose of the utility model and the scope protected by the claims, and these all belong to the protection scope of the utility model.

Claims

1. A temperature protection circuit for a vehicle-mounted electronic outside rearview mirror, connected to a display screen module of the vehicle-mounted electronic outside rearview mirror, characterized in that, The temperature protection circuit comprises: A high-temperature detection module comprising a first power supply, a first sampling resistor R1, a first sampling capacitor C1 and a first thermistor, wherein the first power supply, the first sampling resistor R1 and the first sampling capacitor C1 are connected in series and then connected to a ground terminal, and the first thermistor is connected in parallel with the first sampling capacitor C1; A low-temperature detection module comprising a second power supply, a second sampling resistor R1, a second sampling capacitor C1 and a second thermistor, wherein the second power supply, the second sampling resistor R1 and the second sampling capacitor C1 are connected in series and then connected to a ground terminal, and the second thermistor is connected in parallel with the second sampling capacitor C1, the resistance value of the first sampling resistor R1 is different from that of the second sampling resistor R2, the circuit parameters of the first power supply and the second power supply are the same, and the first thermistor and the second thermistor are the same type of thermistor and generate the same detection current based on the same ambient temperature around the vehicle-mounted electronic outside rearview mirror; A main control module, two input terminals of the main control module are connected to a first sampling point on a line between the first sampling capacitor C1 and the first sampling resistor R1 and a second sampling point on a line between the second sampling capacitor C1 and the second sampling resistor R2 respectively to obtain a first detection voltage and a second detection voltage at the first sampling point and the second sampling point respectively, the main control module is built-in with a first data table reflecting a corresponding relationship between a first detection temperature and a PWM signal duty cycle and a second data table reflecting a corresponding relationship between a second detection temperature and a PWM signal duty cycle, the main control module is configured to calculate the first detection temperature and the second detection temperature according to the first detection voltage and the second detection voltage, determine and sequentially output a PWM signal with a corresponding duty cycle according to the first detection temperature and the first data table when the first detection temperature is greater than or equal to a preset high-temperature threshold, and determine and sequentially output a PWM signal with a corresponding duty cycle according to the second detection temperature and the second data table when the second detection temperature is less than or equal to a preset low-temperature threshold; and A backlight power supply driving module connected to an output terminal of the main control module and the display screen module, built-in with a third data table reflecting a corresponding relationship between a PWM signal duty cycle and a driving current, configured to determine and sequentially output a driving current with a corresponding predetermined size to the display screen module according to a duty cycle of the PWM signal output by the main control module and the third data table.

2. The temperature protection circuit for a vehicular electronic outside mirror according to claim 1, wherein The main control module comprises: A high-temperature sampling unit connected to a first sampling point on a line between the first sampling capacitor C1 and the first sampling resistor R1, configured to obtain a first detection voltage at the first sampling point and calculate a corresponding first detection temperature according to the first detection voltage; A low-temperature sampling unit connected to a second sampling point on a line between the second sampling capacitor C1 and the second sampling resistor R1, configured to obtain a second detection voltage at the second sampling point and calculate a corresponding second detection temperature according to the second detection voltage; a storage unit configured to store the first data table, the second data table, a preset high-temperature threshold, and a preset low-temperature threshold; a comparison unit connected to the high-temperature sampling unit, the low-temperature sampling unit, and the storage unit, and configured to compare the first detection temperature with the preset high-temperature threshold and compare the second detection temperature with the preset low-temperature threshold, output a high-temperature signal when the first detection temperature is greater than or equal to the preset high-temperature threshold, and output a low-temperature signal when the second detection temperature is less than or equal to the preset low-temperature threshold; and a PWM output unit connected to the high-temperature sampling unit, the low-temperature sampling unit, the comparison unit, and the storage unit, and externally connected to the backlight power supply driving module, and configured to determine and sequentially generate and output a first PWM signal with a corresponding duty cycle according to the first detection temperature and the first data table when the high-temperature signal is received, and determine and sequentially generate and output a second PWM signal with a corresponding duty cycle according to the second detection temperature and the second data table when the low-temperature signal is received.

3. The temperature protection circuit for a vehicular electronic outside mirror according to claim 1, wherein The first thermistor and the second thermistor are both NTC thermistors, and a resistance value of the first sampling resistor R1 is less than a resistance value of the second sampling resistor R2.

4. The temperature protection circuit for a vehicular electronic outside mirror according to claim 1, wherein The temperature protection circuit further comprises: a display screen image driving module connected to the main control module and the display screen module, and configured to drive the display screen module to display preset high-temperature warning information when the main control module determines that the first detection temperature is greater than or equal to the preset high-temperature threshold, and drive the display screen module to display preset low-temperature warning information when the main control module determines that the second detection temperature is less than or equal to the preset low-temperature threshold.

5. An electronic outside rearview mirror for a vehicle, comprising a first camera and a second camera arranged separately on both sides of the exterior of the vehicle, a display screen module installed in the driver's cabin of the vehicle and connected to the first camera and the second camera to display the captured images of the first camera and the second camera, and a temperature protection circuit connected to the display screen module, characterized in that, The temperature protection circuit is the temperature protection circuit according to any one of claims 1-4.

6. The vehicle exterior rearview mirror assembly of claim 5, wherein, The display screen module comprises: a main display screen and a sub-display screen respectively installed on a driver seat side and a front passenger seat side of a motor vehicle, and respectively connected to the first camera and the second camera to display a shooting image of the first camera and the second camera; and a main backlight unit and a sub-backlight unit integrated in the main display screen and the sub-display screen to drive the main display screen and the sub-display screen to display; The temperature protection circuit is provided with two backlight power supply driving modules connected to the main backlight unit and the sub-backlight unit.

7. The vehicle exterior rearview mirror assembly of claim 6, wherein, The first thermistor is integrated in the main display screen, and the second thermistor is integrated in the sub-display screen.

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