Light supplementing circuit for vehicle-mounted camera

Abstract

An embodiment of the utility model provides a light supplement circuit for a vehicle-mounted camera, which comprises an LED light supplement lamp, an LED driving chip and a current detection chip, the LED driving chip is provided with an enabling pin, a sampling resistor R1 is arranged in a driving loop between the LED driving chip and the LED light supplement lamp, and the current detection chip is connected with the LED light supplement lamp. The current detection chip is provided with the following pins: a first current detection pin and a second current detection pin which are respectively connected with two opposite ends of the sampling resistor R1; the current setting pin is connected to the grounding end through a threshold value setting resistor R2; the current detection chip detects an actual current value flowing through the sampling resistor R1 through the first current detection pin and the second current detection pin, and compares the actual current value with a current detection threshold value. And when the actual current value is greater than or equal to the current detection threshold value, a low-level signal is output through the feedback pin to promote the LED driving chip to stop working. According to the embodiment of the invention, the LED driving chip can be turned off when the driving current is too large.

Description

Technical Field

[0001] The embodiment of the utility model relates to the technical field of vehicle accessories, and in particular to a fill light circuit for a vehicle camera. Background Art

[0002] In order to effectively monitor the status of the driver and passengers and ensure that clear images can be captured under different lighting conditions, the vehicle-mounted camera installed in the passenger compartment is usually equipped with a fill light circuit on one side of the lens of the vehicle-mounted camera.

[0003] An existing fill light circuit for an on-board camera mainly includes an LED fill light and an LED driver chip connected to the LED fill light to drive the LED fill light to emit light. In order to prevent the LED fill light from being too bright and causing damage to the eyes of the driver or passengers, the dimming accuracy of the LED driver chip is currently required to meet relevant technical certifications (for example, human eye safety certification EN 62471). However, traditional fill light circuits usually only meet the technical standards of ASIL B. Moreover, the driving circuit of the LED driver chip lacks the necessary current detection circuit, resulting in that when the LED driver chip works abnormally but continues to output the current to drive the LED fill light, the LED fill light cannot be turned off normally, and the excessive driving current will cause the fill light brightness to be too strong, which will cause the risk of damage to the human eye and is not conducive to the safe control of the circuit. Utility Model Content

[0004] The technical problem to be solved by the embodiments of the utility model is to provide a fill light circuit for a vehicle-mounted camera, which can effectively turn off the LED driver chip when the driving current is too large to avoid excessive brightness of the fill light.

[0005] In order to solve the above technical problems, the embodiment of the utility model provides the following technical solutions: a fill light circuit for a vehicle-mounted camera, comprising an LED fill light and an LED driver chip connected to the LED fill light and used to connect to an external vehicle-mounted controller to drive the LED fill light to emit light under the control of the external vehicle-mounted controller, the LED driver chip is provided with an enable pin for receiving a high-level signal output by the external vehicle-mounted controller to start the LED driver chip, a sampling resistor R1 is provided in the driving circuit between the LED driver chip and the LED fill light, the fill light circuit also includes a current detection chip, and the current detection chip is provided with the following pins:

[0006] a first current detection pin and a second current detection pin respectively connected to opposite ends of the sampling resistor R1;

[0007] A current setting pin for setting a current detection threshold inside the current detection chip, wherein the current setting pin is connected to a ground terminal through a threshold setting resistor R2; and

[0008] A feedback pin connected to the enable pin, the current detection chip detects the actual current value flowing through the sampling resistor R1 through the first current detection pin and the second current detection pin, compares the actual current value with the current detection threshold, and outputs a low-level signal through the feedback pin when the actual current value is greater than or equal to the current detection threshold to cause the LED driver chip to stop working.

[0009] Furthermore, the LED driver chip is also provided with the following pins:

[0010] A first driving pin connected to the positive electrode of the LED fill light through a switch element SW;

[0011] The second driving pin is connected to the cathode of the LED fill light through the sampling resistor R1;

[0012] A PWM input pin connected to the external vehicle controller to receive a PWM dimming signal output by the external vehicle controller; and

[0013] The PWM output pin is connected to the control end of the switch element SW and is used to output a PWM driving signal matching the PWM dimming signal to control the on and off of the switch element SW.

[0014] Furthermore, the LED driver chip is also provided with the following pins:

[0015] A fault feedback pin, connected to the external vehicle-mounted controller, for outputting a high-level signal when the LED driver chip is operating normally and stopping outputting the high-level signal when a fault occurs; and

[0016] A fault diagnosis pin connected to the external vehicle-mounted controller so that the external vehicle-mounted controller reads the fault data of the LED driver chip through the fault diagnosis pin after detecting that the fault feedback pin stops outputting a high-level signal;

[0017] The enable pin is also used to receive a low level signal output by an external vehicle-mounted controller to stop the LED driver chip from working.

[0018] Furthermore, the current detection chip is also provided with a reset pin for receiving a reset signal output by an external vehicle-mounted controller to reset the current detection chip.

[0019] Furthermore, the LED fill light is an infrared LED light.

[0020] On the other hand, in order to solve the above technical problems, the embodiment of the utility model further provides the following technical solutions: a fill light circuit for a vehicle-mounted camera, comprising an LED fill light and an LED driver chip connected to the LED fill light and used to connect to an external vehicle-mounted controller to drive the LED fill light to emit light under the control of the external vehicle-mounted controller, the LED driver chip is provided with an enable pin for receiving a high-level signal output by the external vehicle-mounted controller to start the LED driver chip and a fault feedback pin for outputting a high-level signal when the LED driver chip works normally and stopping the output of the high-level signal when a fault occurs, a sampling resistor R1 is provided in the driving circuit between the LED driver chip and the LED fill light, the fill light circuit also includes a current detection chip, and the current detection chip is provided with the following pins:

[0021] a first current detection pin and a second current detection pin respectively connected to opposite ends of the sampling resistor R1;

[0022] A current setting pin for setting a current detection threshold inside the current detection chip, wherein the current setting pin is connected to a ground terminal through a threshold setting resistor R2; and

[0023] The feedback pin is connected to the fault feedback pin, and the current detection chip detects the actual current value flowing through the sampling resistor R1 through the first current detection pin and the second current detection pin, compares the actual current value with the current detection threshold, and outputs a low level signal through the feedback pin when the actual current value is greater than or equal to the current detection threshold, prompting the external vehicle controller to output a low level signal to the enable pin according to the low level signal to stop the LED driver chip from working.

[0024] Furthermore, the LED driver chip is also provided with the following pins:

[0025] A first driving pin connected to the positive electrode of the LED fill light through a switch element SW;

[0026] The second driving pin is connected to the cathode of the LED fill light through the sampling resistor R1;

[0027] A PWM input pin connected to the external vehicle controller to receive a PWM dimming signal output by the external vehicle controller; and

[0028] The PWM output pin is connected to the control end of the switch element SW and is used to output a PWM driving signal matching the PWM dimming signal to control the on and off of the switch element SW.

[0029] Furthermore, the LED driver chip is also provided with the following pins:

[0030] A fault diagnosis pin is connected to the external vehicle-mounted controller so that the external vehicle-mounted controller can read the fault data of the LED driver chip through the fault diagnosis pin after detecting that the fault feedback pin stops outputting a high-level signal.

[0031] Furthermore, the current detection chip is also provided with a reset pin for receiving a reset signal output by an external vehicle-mounted controller to reset the current detection chip.

[0032] Furthermore, the LED fill light is an infrared LED light.

[0033] After adopting the above technical scheme, the embodiment of the utility model has at least the following beneficial effects: the embodiment of the utility model sets a sampling resistor R1 in the driving circuit between the LED driver chip and the LED fill light, and adds a current detection chip. The current detection chip can detect the actual current value flowing through the sampling resistor R1 through the first current detection pin and the second current detection pin. By comparing the actual current value with the current detection threshold, the greater the driving current output by the LED driver chip, the greater the actual current value passing through the sampling resistor R1. When the measured actual current value is greater than or equal to the current detection threshold, the current detection chip can output a low-level signal through the feedback pin to lower the level of the enable pin of the LED driver chip, thereby prompting the LED driver chip to stop working, and finally the LED fill light stops filling light, thereby avoiding excessive brightness of the LED fill light. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a circuit principle block diagram of an optional embodiment of a fill light circuit for a vehicle-mounted camera of the present invention.

[0035] Figure 2 The present invention is a circuit principle block diagram of another optional embodiment of the fill light circuit for a vehicle-mounted camera of the present invention. DETAILED DESCRIPTION

[0036] The present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following illustrative embodiments and descriptions are only used to explain the present invention and are not intended to limit the present invention. In addition, the embodiments and features in the embodiments of the present application may be combined with each other without conflict.

[0037] like Figure 1As shown, an optional embodiment of the utility model provides a fill light circuit 3 for a vehicle-mounted camera, including an LED fill light 10 and an LED driver chip 12 connected to the LED fill light 10 and used to connect to an external vehicle-mounted controller 3 to drive the LED fill light 10 to emit light under the control of the external vehicle-mounted controller 3, and the LED driver chip 12 is provided with an enable pin ( Figure 1 and Figure 2 The EN pin in the LED driver chip 12 is provided with a sampling resistor R1 in the driving circuit between the LED driver chip 12 and the LED fill light 10. The fill light circuit 3 also includes a current detection chip 14. The current detection chip 14 has the following pins:

[0038] The first current detection pin and the second current detection pin are respectively connected to the opposite ends of the sampling resistor R1. Figure 1 and Figure 2 IN+ and IN- pins in the );

[0039] A current setting pin ( Figure 1 and Figure 2 LIMIT pin in the circuit), the current setting pin is connected to the ground terminal through the threshold setting resistor R2; and

[0040] The FEEDBACK pin is connected to the ENABLE pin ( Figure 1 and Figure 2 The current detection chip 14 detects the actual current value flowing through the sampling resistor R1 through the first current detection pin and the second current detection pin, compares the actual current value with the current detection threshold, and outputs a low level signal through the feedback pin to stop the LED driver chip 12 when the actual current value is greater than or equal to the current detection threshold.

[0041] The embodiment of the utility model sets a sampling resistor R1 in the driving circuit between the LED driver chip 12 and the LED fill light 10, and adds a current detection chip 14. The current detection chip 14 can detect the actual current value flowing through the sampling resistor R1 through the first current detection pin and the second current detection pin. By comparing the actual current value with the current detection threshold, the larger the driving current output by the LED driver chip 12, the larger the actual current value passing through the sampling resistor R1. When the measured actual current value is greater than or equal to the current detection threshold, the current detection chip 14 can output a low-level signal through the feedback pin to lower the level of the enable pin of the LED driver chip 12, thereby prompting the LED driver chip 12 to stop working, and finally the LED fill light 10 stops filling light, thereby avoiding excessive brightness of the LED fill light 10.

[0042] In a specific implementation, the external vehicle-mounted controller 3 can be a fill light control unit on a vehicle-mounted ECU; in addition, through specific experimental measurements, when the LED driver chip 12 uses a chip that meets ASIL B level (for example: ADI brand MAX25614 chip), the fill light circuit 1 provided by the utility model can meet ASIL C level, and the current detection chip 14 can use TI brand INA301-Q1 chip.

[0043] In an optional embodiment of the present invention, the LED driver chip 12 is further provided with the following pins:

[0044] The first driving pin 121 is connected to the positive electrode of the LED fill light 10 through the switch element SW;

[0045] The second driving pin 123 is connected to the cathode of the LED fill light 10 through the sampling resistor R1;

[0046] PWM input pin ( Figure 1 and Figure 2 ), connected to the external vehicle controller 3 to receive the PWM dimming signal output by the external vehicle controller 3; and

[0047] PWM output pin ( Figure 1 and Figure 2 The DIMOUT pin in the control circuit 1 is connected to the control end of the switch element SW, and is used to output a PWM driving signal matching the PWM dimming signal to control the on / off of the switch element SW.

[0048] In this embodiment, the LED driver chip 12 outputs a PWM drive signal that matches the PWM dimming signal sent by the external vehicle controller 3 (usually with the same frequency) through the PWM output pin, thereby controlling the on and off of the switching element SW, thereby effectively driving the LED fill light 10 to work normally.

[0049] In an optional embodiment of the present invention, the LED driver chip 12 is further provided with the following pins:

[0050] FAULT FEEDBACK PIN ( Figure 1 and Figure 2 FLT# pin in the LED driver chip 12), connected to the external vehicle controller 3, for outputting a high level signal when the LED driver chip 12 is working normally and stopping outputting a high level signal when a fault occurs; and

[0051] Fault diagnosis pin ( Figure 1 and Figure 2 The SCL pin and the SDA pin in the LED driver chip 1 are connected to the external vehicle controller 3 so that the external vehicle controller 3 can read the fault data of the LED driver chip 12 through the fault diagnosis pin after detecting that the fault feedback pin stops outputting a high level signal;

[0052] The enable pin is also used to receive a low level signal output by the external vehicle controller 3 to stop the LED driver chip 12 from working.

[0053] In this embodiment, the fault feedback pin of the LED driver chip 12 outputs a high-level signal by default when the LED driver chip 12 is working normally, and when the LED driver chip 12 is abnormal, the fault feedback pin will stop outputting a high-level signal immediately. At this time, the external vehicle controller 3 knows that the LED driver chip 12 is faulty, and thus uses the fault diagnosis pin of the LED driver chip 12 to detect and read the fault of the LED driver chip 12, so that the vehicle computer can obtain the corresponding fault type and deal with it. In the specific implementation, there are many situations in which the low-level signal output by the external vehicle controller 3 stops the LED driver chip 14 from working, for example: the external vehicle controller 3 needs to actively control the LED fill light 10 to turn off, the external vehicle controller 3 determines that the LED driver chip 12 has a fault and actively controls the LED driver chip 12 to turn off, etc. In addition, the enable pin stops the LED driver chip 14 from working, which usually means that the LED driver chip 14 is controlled to stop driving the LED fill light 10 instead of completely powering off. At this time, the external vehicle controller 3 can still read the fault data of the LED driver chip 14 through the fault diagnosis pin of the LED driver chip 14.

[0054] In an optional embodiment of the present invention, the current detection chip 14 is further provided with a reset pin ( Figure 1 and Figure 2 In this embodiment, the current detection chip 14 is also provided with a reset pin, so that when the current detection chip 14 is abnormal or needs to be reset, the external vehicle controller 3 can control and reset the current detection chip 14.

[0055] In an optional embodiment of the utility model, the LED fill light 10 is an infrared LED lamp. In this embodiment, the infrared LED lamp is invisible to human eyes, has a good fill light effect, and does not interfere with normal driving.

[0056] On the other hand, Figure 2 As shown, the embodiment of the utility model further provides a fill light circuit 3 for a vehicle-mounted camera, comprising an LED fill light 10 and an LED driver chip 12 connected to the LED fill light 10 and used to connect to an external vehicle-mounted controller 3 to drive the LED fill light 10 to emit light under the control of the external vehicle-mounted controller 3, and the LED driver chip 12 is provided with an enable pin ( Figure 1 and Figure 2 The EN pin in the LED driver chip 12 is used to output a high level signal when the LED driver chip 12 is working normally and stop outputting a high level signal when a fault occurs. Figure 1 and Figure 2 The FLT# pin in the LED driver chip 12 is provided with a sampling resistor R1 in the driving circuit between the LED driver chip 12 and the LED fill light 10. The fill light circuit 3 also includes a current detection chip 14. The current detection chip 14 has the following pins:

[0057] a first current detection pin and a second current detection pin respectively connected to opposite ends of the sampling resistor R1;

[0058] A current setting pin for setting a current detection threshold inside the current detection chip 14, wherein the current setting pin is connected to a ground terminal through a threshold setting resistor R2; and

[0059] The feedback pin is connected to the fault feedback pin, and the current detection chip 14 detects the actual current value flowing through the sampling resistor R1 through the first current detection pin and the second current detection pin, compares the actual current value with the current detection threshold, and outputs a low level signal through the feedback pin when the actual current value is greater than or equal to the current detection threshold, prompting the external vehicle controller 3 to output a low level signal to the enable pin according to the low level signal to stop the LED driver chip 12 from working.

[0060] The embodiment of the utility model also provides a fill light circuit 3 for a vehicle-mounted camera. Compared with the aforementioned embodiments, the difference of this embodiment lies in: connecting the feedback pin of the current detection chip 14 to the fault feedback pin of the LED driver chip 12, and utilizing the LED driver chip 12 to output a high-level signal when working normally, and when a current abnormality occurs in the driving circuit of the LED driver chip 12, the feedback pin outputs a low-level signal to lower the level of the fault feedback pin, thereby causing the external vehicle-mounted controller 3 to determine that the LED driver chip 12 has a fault, and then the external vehicle-mounted controller 3 actively outputs a low-level signal to the enable pin of the LED driver chip 12 to stop the LED driver chip 12 from working, thereby avoiding the LED fill light 10 from being too bright and affecting driving.

[0061] The embodiments of the utility model are described above in conjunction with the accompanying drawings, but the utility model is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the utility model, ordinary technicians in this field can also make many forms without departing from the scope of protection of the utility model and the claims, which all belong to the protection scope of the utility model.

Claims

1. A fill light circuit for a vehicle-mounted camera, comprising an LED fill light and an LED driver chip connected to the LED fill light and used to connect to an external vehicle-mounted controller to drive the LED fill light to emit light under the control of the external vehicle-mounted controller, wherein the LED driver chip is provided with an enable pin for receiving a high-level signal output by the external vehicle-mounted controller to start the LED driver chip, characterized in that: A sampling resistor R1 is provided in the driving circuit between the LED driver chip and the LED fill light. The fill light circuit also includes a current detection chip. The current detection chip has the following pins: a first current detection pin and a second current detection pin respectively connected to opposite ends of the sampling resistor R1; A current setting pin for setting a current detection threshold inside the current detection chip, wherein the current setting pin is connected to a ground terminal through a threshold setting resistor R2; and A feedback pin connected to the enable pin, the current detection chip detects the actual current value flowing through the sampling resistor R1 through the first current detection pin and the second current detection pin, compares the actual current value with the current detection threshold, and outputs a low-level signal through the feedback pin when the actual current value is greater than or equal to the current detection threshold to cause the LED driver chip to stop working.

2. The fill light circuit for a vehicle-mounted camera according to claim 1, characterized in that: The LED driver chip is also provided with the following pins: A first driving pin connected to the positive electrode of the LED fill light through a switch element SW; The second driving pin is connected to the cathode of the LED fill light through the sampling resistor R1; A PWM input pin connected to the external vehicle controller to receive a PWM dimming signal output by the external vehicle controller; and The PWM output pin is connected to the control end of the switch element SW and is used to output a PWM driving signal matching the PWM dimming signal to control the on and off of the switch element SW.

3. The fill light circuit for a vehicle-mounted camera according to claim 1 or 2, characterized in that: The LED driver chip is also provided with the following pins: A fault feedback pin, connected to the external vehicle-mounted controller, for outputting a high-level signal when the LED driver chip is operating normally and stopping outputting the high-level signal when a fault occurs; as well as A fault diagnosis pin connected to the external vehicle-mounted controller so that the external vehicle-mounted controller reads the fault data of the LED driver chip through the fault diagnosis pin after detecting that the fault feedback pin stops outputting a high-level signal; The enable pin is also used to receive a low level signal output by an external vehicle-mounted controller to stop the LED driver chip from working.

4. The fill light circuit for a vehicle-mounted camera according to claim 1, characterized in that: The current detection chip is also provided with a reset pin for receiving a reset signal output by an external vehicle-mounted controller to reset the current detection chip.

5. The fill light circuit for a vehicle-mounted camera according to claim 1, characterized in that: The LED fill light is an infrared LED lamp.

6. A fill light circuit for a vehicle-mounted camera, comprising an LED fill light and an LED driver chip connected to the LED fill light and used to connect to an external vehicle-mounted controller to drive the LED fill light to emit light under the control of the external vehicle-mounted controller, wherein the LED driver chip is provided with an enable pin for receiving a high-level signal output by the external vehicle-mounted controller to start the LED driver chip and a fault feedback pin for outputting a high-level signal when the LED driver chip is working normally and stopping outputting the high-level signal when a fault occurs, characterized in that: A sampling resistor R1 is provided in the driving circuit between the LED driver chip and the LED fill light. The fill light circuit also includes a current detection chip. The current detection chip has the following pins: a first current detection pin and a second current detection pin respectively connected to opposite ends of the sampling resistor R1; A current setting pin for setting a current detection threshold inside the current detection chip, wherein the current setting pin is connected to a ground terminal through a threshold setting resistor R2; and The feedback pin is connected to the fault feedback pin, and the current detection chip detects the actual current value flowing through the sampling resistor R1 through the first current detection pin and the second current detection pin, compares the actual current value with the current detection threshold, and outputs a low level signal through the feedback pin when the actual current value is greater than or equal to the current detection threshold, prompting the external vehicle controller to output a low level signal to the enable pin according to the low level signal to stop the LED driver chip from working.

7. The fill light circuit for a vehicle-mounted camera according to claim 6, characterized in that: The LED driver chip is also provided with the following pins: A first driving pin connected to the positive electrode of the LED fill light through a switch element SW; The second driving pin is connected to the cathode of the LED fill light through the sampling resistor R1; A PWM input pin connected to the external vehicle controller to receive a PWM dimming signal output by the external vehicle controller; and The PWM output pin is connected to the control end of the switch element SW and is used to output a PWM driving signal matching the PWM dimming signal to control the on and off of the switch element SW.

8. The fill light circuit for a vehicle-mounted camera according to claim 6 or 7, characterized in that: The LED driver chip is also provided with the following pins: A fault diagnosis pin is connected to the external vehicle-mounted controller so that the external vehicle-mounted controller can read the fault data of the LED driver chip through the fault diagnosis pin after detecting that the fault feedback pin stops outputting a high-level signal.

9. The fill light circuit for a vehicle-mounted camera according to claim 6, characterized in that: The current detection chip is also provided with a reset pin for receiving a reset signal output by an external vehicle-mounted controller to reset the current detection chip.

10. The fill light circuit for a vehicle-mounted camera according to claim 6, characterized in that: The LED fill light is an infrared LED lamp.

Images