A vehicle-mounted electronic rearview mirror and its control circuit

Abstract

The present invention belongs to the technical field of vehicle electronic rearview mirrors, and specifically relates to a vehicle-mounted electronic rearview mirror and a control circuit thereof, wherein the control circuit comprises a power supply circuit and a detection circuit, wherein the control end of the power supply circuit is used to connect to the wake-up signal output end of the vehicle, and the output end of the detection circuit is also used to connect to the wake-up signal output end of the vehicle, and the wake-up signal output end is used to output a preset left end signal or right end signal, and when the wake-up signal is valid, the power supply circuit is controlled to be turned on, and at the same time, the output end of the detection circuit is used to connect to the control unit of the electronic rearview mirror to collect the wake-up signal to run the program on the corresponding side. By setting the above-mentioned control circuit, it is possible to automatically identify whether the picture to be displayed by the electronic rearview mirror is the picture of the camera on the left side or the right side of the vehicle while powering the electronic rearview mirror, so as to run the program on the corresponding side to carry out the display process of the electronic rearview mirror, and then after the external interface of the control circuit is connected accordingly, the electronic rearview mirror can be controlled.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicle electronic rearview mirrors, and in particular relates to a vehicle-mounted electronic rearview mirror and a control circuit thereof. Background Art

[0002] It has become a phenomenon that vehicle electronic rearview mirrors and streaming media rearview mirrors have replaced physical rearview mirrors. After the physical rearview mirrors are cancelled, the installation and debugging of smart cameras on the outside of the vehicle has also brought new problems and challenges. One of them is how to quickly and conveniently adapt the left and right field of view cameras to the corresponding rearview mirror images during the installation and debugging stage.

[0003] First, the following installation distribution of display devices and cameras is introduced:

[0004] like Figure 1a As shown, it is a schematic diagram of the arrangement of the left display device and the left long and short focal length cameras, and Figure 1b The figure shows a schematic diagram of the arrangement of the right display device and the right long-focus and short-focus cameras, that is, the left long-focus camera is located at the top left side of the front of the vehicle and is tilted downward horizontally by about 30°, the left short-focus camera is located outside the left pillar of the front of the vehicle and is tilted vertically backward by about 15°, the left display screen is located on the inner surface of the left pillar and is approximately parallel to the upper edge of the physical rearview mirror from the driver's position, the right long-focus camera is located at the top right side of the front of the vehicle and is tilted downward horizontally by about 30°, the right short-focus camera is located on the right physical rearview mirror pole, and the right display screen is located on the inner surface of the right pillar and is approximately parallel to the upper edge of the right physical rearview mirror from the driver's position.

[0005] Based on the above-mentioned installation arrangement of the display device and the camera, there are three commonly used installation operations of the display device and the camera in the prior art:

[0006] Operation 1: Customize the dedicated left camera and right camera respectively, and distinguish the left and right cameras with labels. During installation, the car manufacturer will correspond the camera devices to the left and right sides of the vehicle according to the labels. This operation can achieve the installation of the left and right display devices in the car without distinguishing between left and right, and the external camera basically does not need to debug the field of view; however, there is a commercial vehicle that needs to be equipped with 4 cameras, and the 4 cameras require 4 different material numbers for management during procurement and storage, which makes it difficult to manage the materials more efficiently and uniformly, thereby increasing the storage space of the camera, that is, the storage cost and management cost are greatly increased, and the appearance of the 4 cameras in the prior art is also very similar, so there will be a phenomenon of wrong installation position during the actual installation process, and the wrong installation position will cause the camera installation to be reworked, resulting in serious problems such as damage to the frame and skin.

[0007] In order to avoid the problem of operation one, the prior art has the following process of operation two: unify the left and right cameras and the display device; however, in order to satisfy the display device to display the corresponding left and right fields of view, the structure of the camera is changed to a 360° adjustable structure, and according to the actual loading situation, the angle of view is rotated during the debugging process to adjust the left and right display screens. However, since this process requires adjusting the field of view of the camera and the display screen of the display device, at least two people are required to perform the debugging work, that is, one person debugs the camera outside the car and the other person checks inside the car to see if the display screen of the display device is appropriate, and the debugging process requires professional personnel to debug, and the debugging angle consistency of the camera based on manual debugging cannot be completely unified. Therefore, although the problem of operation one is avoided, there is a process that requires professional personnel to adjust the camera and the display device.

[0008] In order to avoid the problem of operation one, the prior art also has the following operation three process: unify the left and right cameras and the display device; however, in order to satisfy the display device to display the corresponding left and right fields of view, configure the software through the software, configure the display device installed on the left side to the left side through the software, and configure the display device installed on the right side to the right side through the software, and save the configuration, that is, run different programs on the left and right sides to realize the display of the corresponding left and right fields of view. At the same time, this operation also avoids the installation and debugging work required by two professionals. Only one professional is required to configure the corresponding parameters of the camera to realize the installation and debugging process of the camera and the display device. However, professional debugging personnel are still required to carry out the debugging process, and when replacing the display device or camera, the left and right parameters need to be reconfigured. Therefore, professionals are still needed to carry out maintenance, and there are still maintenance costs. Summary of the invention

[0009] The purpose of the present invention is to provide a vehicle-mounted electronic rearview mirror and a control circuit thereof, so as to solve the problem that in the prior art, when using a unified vehicle-mounted camera and a display device for installation and debugging, professional personnel are still required to perform debugging and maintenance, resulting in corresponding debugging costs and maintenance costs.

[0010] In order to solve the above technical problems, the present invention provides a vehicle-mounted electronic rearview mirror control circuit, including a power supply circuit and a detection circuit, the power supply circuit including a drive switch, the drive switch is arranged between the vehicle power supply output end and the electronic rearview mirror power supply input end, the control end of the drive switch is used to connect the vehicle's wake-up signal output end, the wake-up signal output end is used to output a preset left-end signal or a right-end signal, the left-end signal is a wake-up signal that wakes up the electronic rearview mirror and sets it to the left-end working mode, the right-end signal is a wake-up signal that wakes up the electronic rearview mirror and sets it to the right-end working mode, and the left-end signal is different from the right-end signal, and when the wake-up signal is valid, the drive switch is turned on; the input end of the detection circuit is used to connect the wake-up signal output end, and the output end of the detection circuit is used to connect the control unit of the electronic rearview mirror, so as to collect the wake-up signal after the electronic rearview mirror is powered on, so as to run the program on the corresponding side.

[0011] The beneficial effects are as follows: by setting up a vehicle-mounted electronic rearview mirror control circuit including a power supply circuit and a detection circuit, it is possible to power the electronic rearview mirror while automatically identifying whether the picture to be displayed by the electronic rearview mirror is the picture of the left camera of the vehicle or the picture of the right camera of the vehicle, so as to run the program on the corresponding side to perform the display process of the electronic rearview mirror, and then by connecting the external interfaces of the vehicle-mounted electronic rearview mirror control circuit respectively, the control process of the electronic rearview mirror can be realized, avoiding the problem that the prior art still needs to be debugged after unifying the vehicle-mounted cameras and has the problem of later maintenance costs. And by using the vehicle's wake-up signal output end as both a power supply control end and an output end of the detection circuit, it is possible to make special applications on the wake-up signal and realize the adaptation of the left and right display devices without increasing the pin definition.

[0012] Furthermore, the power supply circuit includes a main branch and a holding branch, and the drive switch is arranged on the main branch so that when the wake-up signal is at a set level, the drive switch is turned on to power the electronic rearview mirror; the holding branch is used to maintain the on state of the drive switch after the wake-up signal changes from a set level to a non-set level, so that the main branch and the holding branch are interlocked.

[0013] By setting up a power supply circuit including a main branch and a holding branch, the main branch can control the driving switch to be turned on when the wake-up signal is at a set level, and after the wake-up signal changes from a set level to a non-set level, the holding branch can maintain the on state of the driving switch, even if the main branch and the holding branch are interlocked, and thus when the wake-up signal is valid, the power supply circuit can still maintain normal power supply to the electronic rearview mirror regardless of how the level changes.

[0014] Furthermore, the driving switch includes a fourth switch tube and a fifth switch tube, the fifth switch tube is arranged between the vehicle power supply output end and the rearview mirror power supply input end, the fourth switch tube is arranged between the control end and the ground end of the fifth switch tube, and the control end of the fourth switch tube is used to connect the wake-up signal output end of the vehicle to control the switching state of the fourth switch tube, and when the wake-up signal is at a set level, the conduction of the fifth switch tube is controlled by the switching state of the fourth switch tube.

[0015] Furthermore, the fourth switch tube is an NPN type transistor, and the fifth switch tube is a PNP type transistor; the emitter of the fifth switch tube is used to connect to the vehicle power supply output terminal, the collector of the fifth switch tube is used to connect to the electronic rearview mirror power supply input terminal, and the base of the fifth switch tube is connected to the collector of the fourth switch tube, so as to control the conduction of the fifth switch tube through the switching state of the fourth switch tube when the wake-up signal is at a set level; the emitter of the fourth switch tube is grounded, and the base of the fourth switch tube is used to connect to the wake-up signal output terminal of the vehicle to control the switching state of the fourth switch tube.

[0016] By connecting the vehicle's wake-up signal output end to the control end of the fourth switch tube (i.e., the base of the fourth switch tube), the conduction and disconnection of the fourth switch tube can be controlled, and the fourth switch tube is connected to the control end of the fifth switch tube, so that when the wake-up signal is at a set level, the conduction of the fifth switch tube can be controlled by the switching state of the fourth switch tube, and then the conduction of the fifth switch tube can be controlled by the vehicle's wake-up signal output end, thereby realizing the function of powering the electronic rearview mirror. Compared with directly controlling one switch tube to realize the on-off state of the power supply circuit, two switch tubes are used, and the state of one switch tube is used to control the state of another switch tube, thereby improving the reliability of control.

[0017] Further, the holding branch includes a first switch tube and a third switch tube; the first switch tube and the third switch tube are arranged in parallel between the vehicle power supply output terminal and the ground terminal, and the control end of the first switch tube is connected to the collector of the fourth switch tube to control the first switch tube to be turned on when the fourth switch tube is turned on; a fifth voltage-dividing resistor is also arranged between the first switch tube and the ground terminal, and a seventh voltage-dividing resistor is also arranged between the third switch tube and the vehicle power supply output terminal. The control end of the first switch tube is also connected to the vehicle power supply output terminal via the seventh voltage-dividing resistor, and the control end of the third switch tube is grounded after the fifth voltage-dividing resistor to turn on the third switch tube when the first switch tube is turned on, and form a conduction state latch, and the control end of the fifth switch tube is connected to the line between the third switch tube and the seventh voltage-dividing resistor, so that when the fourth switch tube changes from being turned on to being turned off, the third switch tube latches the level signal of the control end of the fifth switch tube.

[0018] By using the vehicle's wake-up signal output end as the vehicle's control signal output end and by setting a holding branch, when there is an alternation of high and low levels in the wake-up signal, the level state of the fifth switch tube control end can still be latched through the holding branch, that is, the fifth switch tube is still in the on state, and the power supply of the electronic rearview mirror is not affected, that is, the power supply of the electronic rearview mirror can still be guaranteed by the wake-up signal.

[0019] Furthermore, it also includes an unlocking circuit, the input end of the unlocking circuit is used to connect to the control unit of the vehicle rearview mirror, and the output end of the unlocking circuit controls the third switch tube connected to the holding circuit, so that when the control unit of the vehicle rearview mirror detects that the wake-up signal fails, the switch state of the third switch tube is controlled to change, so as to disconnect the holding branch from maintaining the conduction of the driving switch.

[0020] Furthermore, the unlocking circuit includes an unlocking switch, which is arranged between the control end of the third switch tube of the holding branch and the ground end. The control end of the unlocking switch is used to connect to the control unit of the electronic rearview mirror, so that after the control unit of the electronic rearview mirror detects that the wake-up signal fails, the switch state of the unlocking switch is controlled to be changed, so as to disconnect the driving switch through the switch state of the unlocking switch.

[0021] Furthermore, the unlocking switch is an NPN transistor, the base of the unlocking switch is used to connect to the control unit of the electronic rearview mirror, the emitter of the unlocking switch is used to be grounded, and the collector of the unlocking switch is connected to the control end of the third switch tube.

[0022] By setting up an unlocking circuit, when the wake-up signal fails, the electronic rearview mirror needs to be turned off. Therefore, the control unit of the electronic rearview mirror controls the switch tube of the unlocking circuit to disconnect the holding branch, so as to release the latching of the control end level of the driving switch by the holding branch, thereby realizing the disconnection of the power supply of the electronic rearview mirror. By setting the NPN transistor as an unlocking switch and grounding the emitter, the unlocking switch can be turned on when the control end of the unlocking switch is at a high level, and the unlocking switch can be disconnected when the control end of the unlocking switch is at a low level. Then, the switching state of the unlocking switch can change the level signal of the control end of the third switch tube of the holding branch, thereby controlling the third switch tube to change the switch state to contact the level maintenance of the control end of the driving switch to disconnect the power supply to the electronic rearview mirror.

[0023] Further, when the wake-up signal is a continuous high-level signal or a PWM signal, the wake-up signal is valid.

[0024] To solve the above technical problems, the present invention also provides a vehicle-mounted electronic rearview mirror, including a power supply input terminal and a control unit, and also includes the vehicle-mounted electronic rearview mirror control circuit introduced above, and achieves the same beneficial effects as the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1a It is a schematic diagram of the arrangement of the left display device and the left long and short focal length cameras in the prior art;

[0026] Figure 1b It is a schematic diagram of the arrangement of the right display device and the right long and short focal length cameras in the prior art;

[0027] Figure 2 It is a schematic diagram of the circuit structure of the present invention;

[0028] Figure 3a It is a schematic diagram of the circuit working state when the wake-up signal port of the present invention inputs a high level;

[0029] Figure 3b It is a schematic diagram of the circuit working state when the PWM signal input into the wake-up signal port of the present invention is at a low level;

[0030] Figure 3c It is a schematic diagram of the circuit state when the wake-up signal port of the present invention continuously inputs a low level and the control unit of the electronic rearview mirror outputs a high level. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0032] Vehicle-mounted electronic rearview mirror control circuit embodiment:

[0033] The vehicle-mounted electronic rearview mirror control circuit of this embodiment is applied to a bus (hereinafter referred to as a vehicle), such as Figure 1a and Figure 1b As shown, it is a schematic diagram of the installation position of the electronic rearview mirror and the camera in the prior art. This embodiment selects a camera with a unified fixed structure based on the specific installation position of the prior art, so that almost no debugging is required when installing the camera. In order to enable the display device to display the camera image on the corresponding side without debugging, this embodiment designs the vehicle-mounted electronic rearview mirror control circuit of the present invention.

[0034] The vehicle-mounted electronic rearview mirror control circuit includes a power supply circuit and a detection circuit, the power supply circuit is used to power the vehicle-mounted electronic rearview mirror, and the detection circuit is used to detect which side of the vehicle (the left side of the vehicle or the right side of the vehicle) the image to be displayed by the vehicle-mounted electronic rearview mirror is, so the power supply circuit includes a drive switch, the drive switch is arranged between the vehicle power supply output end and the electronic rearview mirror power supply input end, the control end of the drive switch is used to connect the vehicle's wake-up signal output end, the wake-up signal output end is used to output a preset left end signal or right end signal, and when the wake-up signal is valid, the drive switch is turned on; the input end of the detection circuit is used to connect the wake-up signal output end, and the output end of the detection circuit is used to connect the control unit of the electronic rearview mirror, so as to collect the wake-up signal after the electronic rearview mirror is powered, so as to run the program on the corresponding side (the left side of the vehicle or the right side of the vehicle), that is, through the wake-up signal, determine which side (the left side of the vehicle or the right side of the vehicle) of the connected camera is. The output of the wake-up signal in this embodiment is a preset output, and the wake-up signals on the left and right sides are different. The electronic rearview mirror also stores a corresponding program in advance to run the program on the corresponding side after collecting the corresponding signal.

[0035] By setting up a vehicle-mounted electronic rearview mirror control circuit including a power supply circuit and a detection circuit, it is possible to power the electronic rearview mirror while automatically identifying whether the image to be displayed by the electronic rearview mirror is the image of the left camera of the vehicle or the image of the right camera of the vehicle, so as to run the program on the corresponding side to perform the display process of the electronic rearview mirror, and then by connecting the external interfaces of the vehicle-mounted electronic rearview mirror control circuit respectively, the control process of the electronic rearview mirror can be realized, avoiding the problem that the prior art still needs to be debugged after unifying the vehicle-mounted cameras and has the problem of later maintenance costs. In addition, the power supply and the wake-up signal are necessary conditions for the normal operation of the product, and in ordinary applications, the wake-up signal can only work normally when the high level is valid, and the wake-up signal can be customized. This description is basically the most basic application of each car manufacturer and is very common; therefore, by using the vehicle's wake-up signal output end as both a power supply control end and an output end of the detection circuit, it is possible to make special applications on the wake-up signal, and realize the adaptation of the left and right display devices without increasing the pin definition.

[0036] like Figure 2 The vehicle-mounted electronic rearview mirror control circuit of this embodiment is shown. The acquisition circuit of this embodiment acquires the wake-up signal output end of the vehicle (i.e. Figure 2 The pulse signal of Port_WakeUp in Figure 2 As shown, the acquisition circuit includes a resistor R47 and a resistor R48, and the resistor R47 and the resistor R48 are connected in series to the wake-up signal output end of the vehicle (ie Figure 2 between the Port_WakeUp terminal in the signal acquisition terminal (i.e. Figure 2The Pulse_Check end in the signal acquisition end is used to connect the control unit of the electronic rearview mirror) and is connected to the connection circuit between the resistor R47 and the resistor R48 to reflect the pulse signal through the voltage signal collected by the control unit of the electronic rearview mirror at the signal acquisition end.

[0037] The control end of the power supply circuit of this embodiment is also connected to the wake-up signal output end of the vehicle (i.e. Figure 2 The power supply circuit includes a main branch, the driving switch is arranged on the main branch, the driving switch includes a fourth switch tube Q4 and a fifth switch tube Q5, the fourth switch tube Q4 is connected to the Port_WakeUp end via a resistor R25, and the emitter of the fourth switch tube is grounded, so as to turn on the fourth switch tube when the Port_WakeUp end outputs a high level, the collector of the fourth switch tube is connected to the control end of the fifth switch tube Q5 (i.e., the base of Q5) via a resistor R58, and the emitter of the fifth switch tube Q5 is connected to the vehicle power supply output end (i.e., Figure 2 The BAT terminal in the circuit) is used to pull down the control terminal voltage of the fifth switch tube Q5 when the fourth switch tube Q4 is turned on, so that the fifth switch tube Q5 is turned on, and the collector of the fifth switch tube Q5 is connected to the power supply input terminal of the electronic rearview mirror (i.e. Figure 2 PowerCTR in the figure is used to power the electronic rearview mirror when the fifth switch tube Q5 is turned on, so that the power supply process of the electronic rearview mirror can be realized through the wake-up signal input terminal, and the collector of the fifth switch tube Q5 of this embodiment is also grounded after passing through the resistor R40 and the resistor R41 to input a voltage of (BAT)*R41 / (R40+R41) into the power supply input terminal of the electronic rearview mirror. In addition, the switching state of the present embodiment is to realize the conduction process of the power supply circuit through the fourth switch tube Q4 and the fifth switch tube Q5, that is, by connecting the control signal output end of the vehicle to the control end of the fourth switch tube (that is, the base of the fourth switch tube), the conduction and disconnection of the fourth switch tube can be controlled, and the fourth switch tube is connected to the control end of the fifth switch tube to control the on and off of the fifth switch tube through the switching state of the fourth switch tube, and then the conduction and disconnection of the fifth switch tube can be controlled through the control signal output end of the vehicle, so as to realize the function of power supply and power off of the electronic rearview mirror, and compared with directly controlling one switch tube to realize the on and off state of the power supply circuit, two switch tubes are used, and the state of one switch tube is used to control the state of the other switch tube, thereby improving the reliability of control.

[0038] In this embodiment, the vehicle's wake-up signal output terminal is used as the vehicle's control signal output terminal. Therefore, there may be a low level in the vehicle's wake-up signal. In order to ensure the normal operation of the vehicle-mounted electronic rearview mirror during the low level period of the vehicle's wake-up signal, the power supply circuit of the vehicle-mounted electronic rearview mirror control circuit in this embodiment also includes a holding branch. The holding branch is used to latch the level signal of the control end of the fifth switch tube Q5 in the power supply circuit to achieve the normal operation process during the low level period of the replacement signal. Specifically, Figure 2 As shown, the holding branch includes a first switch tube Q1 and a third switch tube Q3. The first switch tube and the third switch tube are connected in parallel between the vehicle power supply output terminal and the ground terminal (the first switch tube in this embodiment is a PNP type triode, and the emitter is used to connect to the vehicle power supply output terminal, and the third switch tube is an NPN type triode, and the emitter is used to connect to the ground terminal), and are also connected in parallel with the fourth switch tube Q4. A fifth voltage-dividing resistor is also arranged in series on the circuit connecting the first switch tube Q1 to the ground terminal. The fifth voltage-dividing resistor is two resistors R23 and a resistor R29 arranged in series. A seventh voltage-dividing resistor is also arranged in series on the circuit connecting the third switch tube Q3 to the vehicle power supply output terminal. The seventh voltage-dividing resistor is two resistors R24 and a resistor R42 arranged in series. The control end of the first switch tube is connected to the connection point between the resistor R42 and the resistor R24 ​​(that is, the first The control end of the switch tube is connected to the vehicle power supply output end through a voltage-dividing resistor in the circuit where the third switch tube is located), and the control end of the third switch tube is connected to the connection point between the resistor R23 and the resistor R29 (that is, the control end of the third switch tube is connected to the ground end through a voltage-dividing resistor where the first switch tube is located). By setting the holding branch of this embodiment, when the first switch tube is turned on, the third switch tube is also turned on, and when there is no external release signal acting on the control end of the first switch tube or the control end of the third switch tube, the first switch tube and the third switch tube are always kept in the turned-on state. Based on the setting of the holding branch of this embodiment, by connecting the collector of the third switch tube through the resistor R58 to the control end of the fifth switch tube, when the fourth switch tube is disconnected during the low level time period in the wake-up signal, the fifth switch tube can still be turned on through the third switch tube. The control end of the first switch tube is also connected to the fourth switch tube through the resistor R24, so that when the vehicle rearview mirror is initially started, the conduction process of the first switch tube is realized through the conduction state of the fourth switch tube.

[0039] Due to the existence of the holding branch, when the electronic rearview mirror does not need to work (that is, when the wake-up signal is continuously in a low-level state), the holding branch needs to be unlocked, that is, the third switch tube or the fifth switch needs to be controlled to be disconnected to release the conduction state of the fourth switch tube. In this embodiment, the unlocking process of the holding branch is realized by adding an unlocking circuit to the left and right field of view adaptive display circuit of the vehicle-mounted rearview mirror. Figure 2 As shown, the unlocking circuit includes an unlocking switch (i.e. Figure 2 The second switch tube Q2 in the electronic rearview mirror is an NPN transistor), the unlocking switch is arranged between the control end and the grounding end of the third switch tube (that is, the collector of the second switch tube is connected to the base of the third switch tube, and the emitter of the second switch tube is grounded), and the control end of the unlocking switch is used to connect the control unit of the electronic rearview mirror (that is, Figure 2 MCU_PowerCTR terminal in the electronic rearview mirror), so that after the control unit of the electronic rearview mirror detects that the wake-up signal fails, it controls the unlocking switch to turn on, and the unlocking switch disconnects the third switch tube, and the level signal of the control terminal of the fifth switch tube is unlocked, and then the fifth switch tube is disconnected. By setting the unlocking circuit, when the wake-up signal fails, that is, when the wake-up signal is continuously low, the vehicle is in an inoperative state at this time, and the electronic rearview mirror needs to be turned off. Therefore, the control unit of the electronic rearview mirror controls the second switch tube of the unlocking circuit to turn on, and then the third switch tube is disconnected, so as to realize the unlocking of the latching of the control terminal level of the fifth switch tube by the holding branch, and then realize the disconnection of the power supply of the electronic rearview mirror.

[0040] The following process can be realized by the vehicle rearview mirror left and right field of view adaptive display circuit of this embodiment:

[0041] First, in this embodiment, when the wake-up signal is pre-set to be high-level valid, the display device automatically recognizes it as the left display field of view. When the wake-up signal is a 100Hz waveform with a duty cycle of 50%, the display device automatically recognizes it as the right display field of view. Therefore, when there is a wake-up signal in the vehicle, there are two situations: when the Port_WakeUp terminal is at a high level and when the PWM signal is at a low level, and at this time the MCU_PowerCTR terminal is at a low level; when there is no wake-up signal in the vehicle, that is, when the Port_WakeUp terminal is continuously at a low level, the MCU_PowerCTR terminal is at a high level to block the process of supplying power to the electronic rearview mirror, so as to shut down the operation of the electronic rearview mirror. The specific three situations are as follows: Figure 3a , Figure 3b as well as Figure 3c As shown, Figure 3a , Figure 3b as well as Figure 3c The arrows indicate the direction of the pathway.

[0042] like Figure 3aAs shown, it is a schematic diagram of the circuit working state when the wake-up signal port inputs a high level. When the Port_WakeUp terminal inputs a high level, the fourth switch tube is turned on, and then the switch state of the fourth switch tube causes the fifth switch tube and the first switch tube to also be turned on. After the fifth switch tube is turned on and the first switch tube is turned on, the PowerCTR terminal can power the electronic rearview mirror, and the electronic rearview mirror starts to work. The type of the wake-up signal is collected through the control unit of the electronic rearview mirror, and the corresponding program is run to display the corresponding display. After the first switch tube is turned on, the third switch tube is also turned on accordingly, and at this time, the MCU_PowerCTR terminal is at a low level, so the second switch tube is not turned on.

[0043] like Figure 3b As shown, it is a schematic diagram of the circuit working state when the PWM signal input to the wake-up signal port is at a low level. Because a high level already exists before the low level, when the Port_WakeUp end is at a low level in the PWM signal, the fourth switch tube is disconnected, and due to the existence of the third switch tube and the first switch tube in the holding branch, the third switch tube and the first switch tube are still kept in a closed state. At this time, because the third switch tube is in a closed state, there is a voltage difference between the base and the emitter of the fifth switch tube, so the fifth switch tube is still kept in a conducting state, and then when the Port_WakeUp end is at a low level in the PWM signal, the power supply to the electronic rearview mirror is not affected.

[0044] like Figure 3c As shown, it is a schematic diagram of the circuit state when the wake-up signal port continuously inputs a low level and the control unit of the electronic rearview mirror outputs a high level. When the Port_WakeUp terminal is continuously at a low level, it means that the wake-up signal has failed and the product needs to be shut down. At this time, the fourth switch tube Q4 is disconnected, that is, when the control unit of the electronic rearview mirror collects a continuous low-level signal, the MCU_PowerCTR terminal is controlled to be at a high level. At this time, the second switch tube Q2 is closed, which causes the third switch tube Q3 to be disconnected. Because the third switch tube Q3 and the fourth switch tube Q4 are both disconnected, the first switch tube Q1 and the fifth switch tube Q5 are also disconnected. Because the fifth switch tube Q5 is also disconnected, the power supply to the electronic rearview mirror is disconnected, that is, the PowerCTR output is low, and the voltage is in the range of 0 to 0.3V, which cannot meet the device operating voltage range requirements; the product is in a non-working state.

[0045] In order to ensure the reliability of the product in the present invention, the signal sources of the left and right display screens are independent, that is, the left and right electronic rearview mirrors are both provided with the vehicle-mounted electronic rearview mirror control circuit of the present embodiment, that is, by providing the vehicle-mounted electronic rearview mirror control circuit including a power supply circuit and a detection circuit, it is possible to power the electronic rearview mirror while automatically identifying whether the picture to be displayed by the electronic rearview mirror is the picture of the left camera of the vehicle or the picture of the right camera of the vehicle, so as to run the program on the corresponding side to perform the display process of the electronic rearview mirror, and then by connecting the external interfaces of the vehicle-mounted electronic rearview mirror control circuit respectively, the process of adaptive display of the left and right fields of view of the electronic rearview mirror can be realized, thereby avoiding the problem that the prior art still needs to debug after unifying the vehicle-mounted cameras and has the cost of subsequent maintenance.

[0046] Vehicle-mounted electronic rearview mirror embodiment:

[0047] The vehicle-mounted electronic rearview mirror of this embodiment includes a power supply input terminal, a control unit and a vehicle-mounted electronic rearview mirror control circuit. The connection relationship between the vehicle-mounted electronic rearview mirror control circuit and the power supply input terminal and the control unit, as well as the vehicle-mounted electronic rearview mirror control circuit have been introduced clearly enough in the embodiment of the vehicle-mounted electronic rearview mirror control circuit and will not be repeated here.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A vehicle-mounted electronic rearview mirror control circuit, characterized in that: The invention comprises a power supply circuit and a detection circuit, wherein the power supply circuit comprises a driving switch, wherein the driving switch is arranged between the power supply output terminal of the vehicle and the power supply input terminal of the electronic rearview mirror, wherein the control terminal of the driving switch is used to connect the wake-up signal output terminal of the vehicle, wherein the wake-up signal output terminal is used to output a preset left-end signal or a right-end signal, wherein the left-end signal is a wake-up signal for waking up the electronic rearview mirror and setting it to the left-end working mode, and the right-end signal is a wake-up signal for waking up the electronic rearview mirror and setting it to the right-end working mode, and the left-end signal is different from the right-end signal, and when the wake-up signal is valid, the driving switch is turned on; the input terminal of the detection circuit is used to connect the wake-up signal output terminal, and the output terminal of the detection circuit is used to connect the control unit of the electronic rearview mirror, so as to collect the wake-up signal after the electronic rearview mirror is powered on, and according to the wake-up signal, automatically identify whether the picture to be displayed by the electronic rearview mirror is the picture of the left camera of the vehicle or the picture of the right camera of the vehicle, so as to run the program on the corresponding side to carry out the display process of the electronic rearview mirror.

2. The vehicle-mounted electronic rearview mirror control circuit according to claim 1, characterized in that: The power supply circuit includes a main branch and a holding branch. The drive switch is arranged on the main branch so that when the wake-up signal is at a set level, the drive switch is turned on to power the electronic rearview mirror; the holding branch is used to maintain the on state of the drive switch after the wake-up signal changes from a set level to a non-set level, so that the main branch and the holding branch are interlocked.

3. The vehicle-mounted electronic rearview mirror control circuit according to claim 2, characterized in that: The driving switch includes a fourth switch tube and a fifth switch tube. The fifth switch tube is arranged between the vehicle power supply output end and the rearview mirror power supply input end. The fourth switch tube is arranged between the control end and the ground end of the fifth switch tube. The control end of the fourth switch tube is used to connect the wake-up signal output end of the vehicle to control the switching state of the fourth switch tube, and when the wake-up signal is at a set level, the conduction of the fifth switch tube is controlled by the switching state of the fourth switch tube.

4. The vehicle-mounted electronic rearview mirror control circuit according to claim 3, characterized in that: The fourth switch tube is an NPN type transistor, and the fifth switch tube is a PNP type transistor; the emitter of the fifth switch tube is used to connect to the vehicle power supply output end, the collector of the fifth switch tube is used to connect to the electronic rearview mirror power supply input end, and the base of the fifth switch tube is connected to the collector of the fourth switch tube, so as to control the conduction of the fifth switch tube through the switching state of the fourth switch tube when the wake-up signal is at a set level; the emitter of the fourth switch tube is grounded, and the base of the fourth switch tube is used to connect to the wake-up signal output end of the vehicle to control the switching state of the fourth switch tube.

5. The vehicle-mounted electronic rearview mirror control circuit according to claim 4, characterized in that: The holding branch includes a first switch tube and a third switch tube; the first switch tube and the third switch tube are arranged in parallel between the vehicle power supply output terminal and the ground terminal, and the control end of the first switch tube is connected to the collector of the fourth switch tube to control the first switch tube to be turned on when the fourth switch tube is turned on; a fifth voltage-dividing resistor is also arranged between the first switch tube and the ground terminal, and a seventh voltage-dividing resistor is also arranged between the third switch tube and the vehicle power supply output terminal. The control end of the first switch tube is also connected to the vehicle power supply output terminal via the seventh voltage-dividing resistor, and the control end of the third switch tube is grounded after the fifth voltage-dividing resistor to turn on the third switch tube when the first switch tube is turned on, and form a conduction state latch, and the control end of the fifth switch tube is connected to the line between the third switch tube and the seventh voltage-dividing resistor, so that when the fourth switch tube changes from being turned on to being turned off, the third switch tube latches the level signal of the control end of the fifth switch tube.

6. The vehicle-mounted electronic rearview mirror control circuit according to claim 5, characterized in that: It also includes an unlocking circuit, the input end of which is used to connect to the control unit of the vehicle rearview mirror, and the output end of the unlocking circuit controls the third switch tube connected to the holding circuit, so that when the control unit of the vehicle rearview mirror detects that the wake-up signal fails, the switch state of the third switch tube is controlled to change, so as to disconnect the holding branch from maintaining the conduction of the driving switch.

7. The vehicle-mounted electronic rearview mirror control circuit according to claim 6, characterized in that: The unlocking circuit includes an unlocking switch, which is arranged between the control end of the third switch tube of the holding branch and the ground end. The control end of the unlocking switch is used to connect to the control unit of the electronic rearview mirror, so that after the control unit of the electronic rearview mirror detects that the wake-up signal fails, the switch state of the unlocking switch is controlled to be changed, so as to disconnect the driving switch through the switch state of the unlocking switch.

8. The vehicle-mounted electronic rearview mirror control circuit according to claim 7, characterized in that: The unlocking switch is an NPN transistor, the base of the unlocking switch is used to connect to the control unit of the electronic rearview mirror, the emitter of the unlocking switch is used to ground, and the collector of the unlocking switch is connected to the control end of the third switch tube.

9. The vehicle-mounted electronic rearview mirror control circuit according to claim 1, characterized in that: The wake-up signal is valid when the wake-up signal is a continuous high-level signal or a PWM signal.

10. A vehicle-mounted electronic rearview mirror, comprising a power supply input terminal and a control unit, characterized in that: It also includes the vehicle-mounted electronic rearview mirror control circuit as described in any one of claims 1 to 9.

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