CN221995563U - POC power supply circuit for vehicle-mounted cameras - Google Patents
POC power supply circuit for vehicle-mounted cameras Download PDFInfo
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- CN221995563U CN221995563U CN202420268897.5U CN202420268897U CN221995563U CN 221995563 U CN221995563 U CN 221995563U CN 202420268897 U CN202420268897 U CN 202420268897U CN 221995563 U CN221995563 U CN 221995563U
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- 238000005070 sampling Methods 0.000 claims description 24
- 239000003990 capacitor Substances 0.000 claims description 15
- 239000011324 bead Substances 0.000 claims description 4
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
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Abstract
The embodiment of the utility model provides a POC power supply circuit for a vehicle-mounted camera, which comprises a main control chip, a first triode Q1, a second triode Q2 and a third triode Q3, wherein the main control chip is provided with an enabling pin for outputting a high level by default, and the POC power supply circuit comprises: the input end of the first triode Q1 is respectively connected to the control end of the second triode Q2 and the output end of the third triode Q3, the output end of the first triode Q1 is connected to the ground end, and the control end of the first triode Q1 is connected to the enabling pin; the input end of the second triode Q2 is connected to the control end of the third triode Q3 on one hand, and is connected to an external power supply voltage source and the input end of the third triode Q3 through a first resistor R1 on the other hand, and the output end of the second triode Q2 is used as a power supply port of the circuit to be connected to a power supply port of the vehicle-mounted camera. The circuit of the embodiment has lower cost and can effectively realize current limiting protection.
Description
Technical Field
The embodiment of the utility model relates to the technical field of camera power supply circuits, in particular to a POC power supply circuit for a vehicle-mounted camera.
Background
In order to realize current supply to the vehicle-mounted camera and data interaction with the vehicle-mounted camera, the existing vehicle-mounted camera generally adopts a POC (Power Over Coaxial, coaxial power supply) principle to realize power supply and data communication simultaneously.
In order to prevent the damage to the vehicle-mounted camera caused by the overlarge supply current of the external power supply source (usually a vehicle-mounted battery), the current limiting protection chip is generally arranged in the conventional POC power supply circuit for the vehicle-mounted camera, and when the supply current input by the external power supply source is overlarge, the current limiting protection chip can automatically disconnect a power supply circuit between the external power supply source and the vehicle-mounted camera, so that the vehicle-mounted camera is protected. However, the cost of the current limiting protection chip is generally high, and the production cost is increased.
Disclosure of utility model
The technical problem to be solved by the embodiment of the utility model is to provide the POC power supply circuit for the vehicle-mounted camera, which has lower cost and can effectively realize current limiting protection.
In order to solve the technical problems, the embodiment of the utility model provides the following technical scheme: a POC power circuit for an in-vehicle camera, comprising:
Main control chip, first triode Q1, second triode Q2 and third triode Q3, main control chip has the enabling pin that is used for defaulting output high level, wherein:
The input end of the first triode Q1 is respectively connected to the control end of the second triode Q2 and the output end of the third triode Q3, the output end of the first triode Q1 is connected to the ground end, and the control end of the first triode Q1 is connected to the enabling pin;
The input end of the second triode Q2 is connected to the control end of the third triode Q3 on one hand, and is connected to an external power supply voltage source and the input end of the third triode Q3 through a first resistor R1 on the other hand, and the output end of the second triode Q2 is used as a power supply port of the circuit to be connected to a power supply port of the vehicle-mounted camera.
Further, the main control chip is further provided with a voltage sampling pin, and is further used for judging in real time that the actual voltage value input by the voltage sampling pin is larger than or equal to a preset voltage threshold value, and if so, adjusting the enabling pin to output a low level;
The output end of the second triode Q2 is further connected to the ground end through a series connection body of a second resistor R2 and a third resistor R3, the third resistor R3 is further connected with the first capacitor C1 in parallel, and a circuit between the second resistor R2 and the third resistor R3 is used as a voltage sampling point to be connected to the voltage sampling pin.
Further, the output end of the second triode Q2 is further connected to an external reference voltage source and the input end of the third triode Q3 through a fourth resistor R4, and the main control chip is further configured to determine, when power is on, whether an actual voltage value input by the voltage sampling pin is within a preset voltage range, and if not, output an alarm signal, where the circuit further includes:
And the alarm unit is connected with the main control chip and is used for responding to the alarm signal to alarm.
Further, the main control chip is further provided with a reference voltage pin, the circuit further comprises a first diode D1 and a second diode D2, wherein the negative electrode of the first diode D1 and the positive electrode of the second diode D2 are both connected to the voltage sampling point, the positive electrode of the first diode D1 is connected to the grounding end, and the negative electrode of the second diode D2 is connected to the reference voltage pin.
Further, the first resistor R1 is connected to the external power supply voltage source through a third diode D3, wherein a positive electrode of the third diode D3 is connected to the external power supply voltage source, and a negative electrode of the third diode D3 is connected to the first resistor R1.
Further, the input end of the third triode Q3 is further connected to the ground end through a parallel connection body of the second capacitor C2 and the third capacitor C3.
Further, the output terminal of the second triode Q2 is further connected to the ground terminal through a fourth capacitor C4.
Further, the output end of the second triode Q2 is further connected to the power supply port through a magnetic bead FB.
Further, the input end of the first triode Q1 is connected to the control end of the second triode Q2 and the output end of the third triode Q3 through a fifth resistor R5, respectively.
After the technical scheme is adopted, the embodiment of the utility model has at least the following beneficial effects: according to the circuit, the main control chip, the first triode Q1, the second triode Q2 and the third triode Q3 are additionally arranged, the enabling pin of the main control chip is used for outputting high level to control the first triode Q1 to be conducted, the second triode Q2 is further conducted, an external power supply voltage source supplies power to the vehicle-mounted camera, and meanwhile the third triode Q3 is conducted; when the power supply current of the external power supply voltage source is overlarge, the current of the control end of the third triode Q3 is increased, so that the current of the output end of the third triode Q3 is increased, the current of the control end of the second triode Q2 is finally increased, the second triode Q2 is cut off, a power supply circuit is disconnected, the external power supply voltage source stops the power supply of the vehicle-mounted camera, and current limiting protection is automatically realized; furthermore, the overall circuit uses fewer circuit elements and the circuit cost is relatively lower.
Drawings
Fig. 1 is a circuit schematic diagram of an alternative embodiment of the POC power circuit for an in-vehicle camera of the present utility model.
Detailed Description
The utility model will be described in further detail with reference to the drawings and the specific examples. It should be understood that the following exemplary embodiments and descriptions are only for the purpose of illustrating the utility model and are not to be construed as limiting the utility model, and that the embodiments and features of the embodiments of the utility model may be combined with one another without conflict.
As shown in fig. 1, an alternative embodiment of the present utility model provides a POC power supply circuit for an in-vehicle camera, including:
The main control chip 1, the first triode Q1, the second triode Q2 and the third triode Q3, the main control chip 1 is provided with an enabling pin 10 for outputting a high level by default, wherein:
The input end of the first triode Q1 is respectively connected to the control end of the second triode Q2 and the output end of the third triode Q3, the output end of the first triode Q1 is connected to the ground end, and the control end of the first triode Q1 is connected to the enabling pin 10;
The input end of the second triode Q2 is connected to the control end of the third triode Q3 on one hand, and is connected to an external power supply voltage source 3 and the input end of the third triode Q3 through a first resistor R1 on the other hand, and the output end of the second triode Q2 is used as a power supply port 5 of the circuit to be connected to a power supply port 70 of the vehicle-mounted camera 7.
According to the circuit, the main control chip 1, the first triode Q1, the second triode Q2 and the third triode Q3 are additionally arranged, the enabling pin 10 of the main control chip 1 is used for outputting high level to control the first triode Q1 to be conducted, the second triode Q2 is further conducted, an external power supply voltage source 3 supplies power to the vehicle-mounted camera 7, and meanwhile the third triode Q3 is conducted; when the power supply current of the external power supply voltage source 3 is overlarge, the current of the control end of the third triode Q3 is increased, so that the current of the output end of the third triode Q3 is increased, the current of the control end of the second triode Q2 is finally increased, the second triode Q2 is cut off, a power supply circuit is disconnected, the external power supply voltage source 3 stops the power supply of the vehicle-mounted camera 7, and current limiting protection is automatically realized; furthermore, the overall circuit uses fewer circuit elements and the circuit cost is relatively lower.
In specific implementation, the control principle of the main control chip 1 is simple, and the main control chip can be realized by adopting a conventional singlechip. The input end, the output end and the control end of the first triode Q1, the second triode Q2 and the third triode Q3 can be distinguished according to different specific types of triodes; as shown in fig. 1, the first triode Q1 is an NPN triode, the input end, the output end and the control end of which are respectively a collector, an emitter and a base, and the second triode Q2 and the third triode Q3 are respectively PNP triodes, the input end, the output end and the control end of which are respectively an emitter, a collector and a base.
In the implementation, different resistance values can be flexibly selected through the first resistor R1, so that current limiting protection of different current sizes of the circuit can be realized; the maximum current value imax=0.65/R1 output by the external supply voltage source 3.
In an optional embodiment of the present utility model, the main control chip 1 further has a voltage sampling pin 12, and the main control chip 1 is further configured to determine in real time whether an actual voltage value input by the voltage sampling pin 12 is greater than a preset voltage threshold, and if yes, adjust the enable pin 10 to output a low level;
The output end of the second triode Q2 is further connected to the ground end through a series connection body of a second resistor R2 and a third resistor R3, the third resistor R3 is further connected with the first capacitor C1 in parallel, and a circuit between the second resistor R2 and the third resistor R3 is used as a voltage sampling point A to be connected to the voltage sampling pin 12.
In this embodiment, the voltage value of the sampling point a between the second resistor R2 and the third resistor R3 is also collected through the voltage sampling pin 12 of the main control chip 1, so that when the input current of the external power supply voltage source 3 is too large, the main control chip 1 can autonomously control the enable pin 10 to output a low level through internal logic control, so that the first triode Q1 is turned off, the second triode Q2 is turned off, and the power supply circuit is turned off, thereby realizing the current limiting control of the main control chip 1.
In an alternative embodiment of the present utility model, the output terminal of the second triode Q2 is further connected to the external reference voltage source 8 and the input terminal of the third triode Q3 through a fourth resistor R4, respectively, and the main control chip 1 is further configured to determine, when power is applied, whether the actual voltage value input by the voltage sampling pin 12 is within a preset voltage range, and if not, output an alarm signal, where the circuit further includes:
And the alarm unit 9 is connected with the main control chip 1 and is used for responding to the alarm signal to alarm.
In this embodiment, the output end of the second triode Q2 is further connected to the external reference voltage source 8 and the input end of the third triode Q3 through the fourth resistor R4 respectively, when the main control chip 1 is powered on, the main control chip 1 can also collect the voltage value at the input end of the third triode Q3 through the sampling circuit formed by the fourth resistor R4, the second resistor R2 and the third resistor R3, and can quickly judge whether the voltage value at the input end of the third triode Q3 is abnormal by combining the standard reference voltage value output by the external reference voltage source 8, so that the first triode Q1 and the second triode Q2 are in a cut-off state before normal power supply is ensured, and meanwhile, whether faults such as open circuit and short circuit exist in the circuit can be judged, so that the safety of the circuit is improved.
In an alternative embodiment of the present utility model, the main control chip 1 further has a reference voltage pin 14, and the circuit further includes a first diode D1 and a second diode D2, where a cathode of the first diode D1 and an anode of the second diode D2 are both connected to the voltage sampling point a, an anode of the first diode D1 is connected to a ground terminal, and a cathode of the second diode D2 is connected to the reference voltage pin 14. In order to prevent the voltage value at the voltage sampling point a from exceeding the default internal reference voltage (e.g., 3.3V) of the main control chip 1 by an excessive voltage value (e.g., 5V) and damaging the voltage sampling pin 12 of the main control chip 1, in this embodiment, the voltage value at the voltage sampling point a is used as the reference voltage to be input into the reference voltage pin 14 of the main control chip 1 by adding the first diode D1 and the second diode D2, thereby protecting the main control chip 1.
In an alternative embodiment of the utility model, the first resistor R1 is connected to the external supply voltage source 3 via a third diode D3, wherein the positive pole of the third diode D3 is connected to the external supply voltage source 3 and the negative pole of the third diode D3 is connected to the first resistor R1. In this embodiment, the third diode D3 is additionally provided, so that reverse connection protection can be achieved.
In an alternative embodiment of the present utility model, the input terminal of the third triode Q3 is further connected to the ground through a parallel connection of the second capacitor C2 and the third capacitor C3. In this embodiment, the second capacitor C2 and the third capacitor C3 are further added, so that clutter interference in the input current of the external power supply voltage source 3 is effectively filtered, and stability of the circuit is improved.
In an alternative embodiment of the present utility model, the output terminal of the second transistor Q2 is further connected to the ground terminal through a fourth capacitor C4. In this embodiment, the fourth capacitor C4 is further provided to implement filtering at the power supply port 5 of the circuit, so as to improve stability of the circuit.
In an alternative embodiment of the present utility model, the output terminal of the second transistor Q2 is further connected to the power supply port 5 through a magnetic bead FB. In this embodiment, the magnetic bead FB is further provided to protect the circuit from external electromagnetic radiation, and to improve the accuracy of the circuit by suppressing the high frequency signal.
In an alternative embodiment of the present utility model, the input terminal of the first transistor Q1 is connected to the control terminal of the second transistor Q2 and the output terminal of the third transistor Q3 through a fifth resistor R5, respectively. In this embodiment, the fifth resistor R5 is further added to stabilize the current, so as to effectively protect the first triode Q1.
The embodiments of the present utility model have been described above with reference to the accompanying drawings, but the present utility model is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present utility model and the scope of the claims, which are all within the scope of the present utility model.
Claims (9)
1. A POC power circuit for an in-vehicle camera, the circuit comprising:
Main control chip, first triode Q1, second triode Q2 and third triode Q3, main control chip has the enabling pin that is used for defaulting output high level, wherein:
The input end of the first triode Q1 is respectively connected to the control end of the second triode Q2 and the output end of the third triode Q3, the output end of the first triode Q1 is connected to the ground end, and the control end of the first triode Q1 is connected to the enabling pin;
The input end of the second triode Q2 is connected to the control end of the third triode Q3 on one hand, and is connected to an external power supply voltage source and the input end of the third triode Q3 through a first resistor R1 on the other hand, and the output end of the second triode Q2 is used as a power supply port of the circuit to be connected to a power supply port of the vehicle-mounted camera.
2. The POC power supply circuit for a vehicle-mounted camera of claim 1, wherein the main control chip further has a voltage sampling pin, and the main control chip is further configured to determine in real time whether an actual voltage value input by the voltage sampling pin is greater than a preset voltage threshold, and if so, adjust the enable pin to output a low level;
The output end of the second triode Q2 is further connected to the ground end through a series connection body of a second resistor R2 and a third resistor R3, the third resistor R3 is further connected with the first capacitor C1 in parallel, and a circuit between the second resistor R2 and the third resistor R3 is used as a voltage sampling point to be connected to the voltage sampling pin.
3. The POC power supply circuit for a vehicle-mounted camera of claim 2, wherein the output terminal of the second transistor Q2 is further connected to an external reference voltage source and the input terminal of the third transistor Q3 through a fourth resistor R4, respectively, the main control chip is further configured to determine, when the power is on, whether an actual voltage value input by the voltage sampling pin is within a preset voltage range, and if not, output an alarm signal, the circuit further includes:
And the alarm unit is connected with the main control chip and is used for responding to the alarm signal to alarm.
4. A POC power supply circuit for a vehicle camera as claimed in claim 2 or 3, wherein said main control chip further has a reference voltage pin, said circuit further comprising a first diode D1 and a second diode D2, wherein both the cathode of said first diode D1 and the anode of said second diode D2 are connected to said voltage sampling point, the anode of said first diode D1 is connected to ground, and the cathode of said second diode D2 is connected to said reference voltage pin.
5. POC power supply circuit for a vehicle camera according to claim 1, wherein the first resistor R1 is connected to the external supply voltage source through a third diode D3, wherein the positive pole of the third diode D3 is connected to the external supply voltage source and the negative pole of the third diode D3 is connected to the first resistor R1.
6. The POC power circuit for a vehicle camera of claim 1, wherein the input terminal of the third transistor Q3 is further connected to ground through a parallel connection of a second capacitor C2 and a third capacitor C3.
7. The POC power circuit for a vehicle camera of claim 1, wherein the output terminal of the second transistor Q2 is further connected to ground through a fourth capacitor C4.
8. The POC power circuit for a vehicle camera of claim 1, wherein the output of the second transistor Q2 is further connected to the power port through a magnetic bead FB.
9. The POC power supply circuit for a vehicle camera of claim 1, wherein an input terminal of the first transistor Q1 is connected to a control terminal of the second transistor Q2 and an output terminal of the third transistor Q3, respectively, through a fifth resistor R5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202420268897.5U CN221995563U (en) | 2024-02-02 | 2024-02-02 | POC power supply circuit for vehicle-mounted cameras |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202420268897.5U CN221995563U (en) | 2024-02-02 | 2024-02-02 | POC power supply circuit for vehicle-mounted cameras |
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| Publication Number | Publication Date |
|---|---|
| CN221995563U true CN221995563U (en) | 2024-11-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202420268897.5U Active CN221995563U (en) | 2024-02-02 | 2024-02-02 | POC power supply circuit for vehicle-mounted cameras |
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| Country | Link |
|---|---|
| CN (1) | CN221995563U (en) |
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- 2024-02-02 CN CN202420268897.5U patent/CN221995563U/en active Active
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