CN106303342B - Power supply circuit based on coaxial power supply technology - Google Patents

Abstract

A power supply circuit based on a coaxial power supply technology comprises a processing circuit of a video processing end, wherein the processing circuit comprises a detection circuit and a control circuit; the detection circuit is used for detecting the electric parameter of the access port of the video processing end; and the control circuit is used for controlling the on-off of the power supply output of the image acquisition terminal by the access port according to the electric parameter. The electric parameter is a voltage value and/or a current value, and the access port is a port accessed to the image acquisition terminal. Therefore, the power supply circuit based on the coaxial power supply technology can identify whether the image acquisition terminal externally connected with the video processing end supports the coaxial power supply or not by detecting and analyzing the electric parameters of the access port of the video processing end, and further judge whether the image acquisition terminal needs to be powered or not according to the analysis result, so that the safety is high.

Description

A power supply circuit based on coaxial power supply technology

technical field

The invention relates to the technical field of security image acquisition, in particular to a power supply circuit based on coaxial power supply technology.

Background technique

Power over coaxial (POC, Power Over Coaxia) is a coaxial cable-based video, coaxial control, and power overlay transmission technology. In the process of coaxial cable transmission, both analog video signal, coaxial signal and power are transmitted, that is, analog video, coaxial and other signals are combined with power supply and transmitted on one coaxial cable. Applying this POC technology for engineering wiring can not only save considerable costs, but also shorten the construction time, and is currently widely used. For devices that support POC power supply, such as POC cameras (analog cameras that support coaxial power supply), after connecting with the coaxial power supply circuit through the coaxial cable, a DC power supply will be superimposed on the coaxial cable, and the voltage of the DC power supply is relatively high. , usually up to 10V and above. Connecting this voltage to the POC camera can meet the power supply requirements, but if the customer mistakenly connects an ordinary analog camera (not supporting POC) to this voltage, the problem of burning the ordinary camera will occur.

Contents of the invention

The purpose of the present invention is to provide a power supply circuit based on coaxial power supply technology, which can distinguish whether the image acquisition terminal externally connected to the video processing end supports coaxial power supply by detecting the electrical parameters of the access port of the video processing end, and further judge whether It needs to supply power to the image acquisition terminal, which has high security.

According to the present invention, a power supply circuit based on coaxial power supply technology is provided, including a processing circuit of a video processing terminal, the processing circuit includes a detection circuit and a control circuit, and the detection circuit and the control circuit are electrically connected;

The detection circuit is used to detect an electrical parameter of an access port of the video processing terminal, the electrical parameter is a voltage value and/or a current value, and the access port is a port for accessing an image acquisition terminal;

The control circuit is configured to control the power output of the access port to the image acquisition terminal on and off according to the electrical parameter.

Wherein, the control circuit includes a turn-on unit and a cut-off unit;

The conduction unit is configured to conduct the power output of the access port to the image acquisition terminal if the electric parameter belongs to the preset first electric parameter range;

The cutting unit is configured to cut off the power output of the inlet port to the image acquisition terminal if the electric parameter belongs to a preset second electric parameter range.

Wherein, the control circuit includes a turn-on unit and a cut-off unit;

The conduction unit is configured to conduct the conduction of the access port to the The power output of the image acquisition terminal;

The cut-off unit is configured to cut off the access port to the image collection terminal when the power output of the image acquisition terminal is turned on and the change value of the electric parameter exceeds a preset stable electric parameter range. Collect the power output of the terminal.

Wherein, the processing circuit further includes a power supply circuit, a video processing circuit, a first isolation unit, a superposition circuit, a switch and a voltage dividing unit.

Wherein, the signal input end of the detection circuit is respectively connected to one end of the voltage dividing unit, the first inlet of the externally connected coaxial cable, the first fixed end of the switch, and one end of the first isolation unit. The signal output end is connected to the signal input end of the control circuit, the signal output end of the control circuit is connected to the moving end of the switch, the second fixed end of the switch is connected to one end of the superposition circuit, and the other end of the superposition circuit is connected to A power supply circuit, the other end of the voltage dividing unit is connected to the input power end for detection, and the other end of the first isolation unit is connected to the video processing circuit.

Wherein, the first isolation unit is a capacitor C1.

Wherein, the voltage dividing unit is a resistor R1.

Wherein, the second inlet of the externally connected coaxial cable is connected to the image acquisition terminal circuit.

Wherein, the image acquisition terminal circuit includes a coaxial power supply circuit, a video signal processing circuit, a power receiving circuit, a matching unit and a second isolation unit.

Wherein, one end of the coaxial power supply circuit is respectively connected to the second inlet of the external coaxial cable and one end of the matching unit, and the other end of the matching unit is connected to one end of the second isolation unit, and the second The other end of the isolation unit is connected to the video signal processing circuit, and the other end of the coaxial power supply circuit is connected to the power receiving circuit.

Wherein, the matching unit is a resistor R2.

Wherein, the resistance value of the resistor R2 is 75 ohms.

Wherein, the second isolation unit is a capacitor C2.

Wherein, the image acquisition terminal circuit includes a matching unit and a video signal processing circuit.

Wherein, one end of the matching unit is the second inlet of the externally connected coaxial cable, and the other end of the matching unit is connected to the video signal processing circuit.

Wherein, the processing circuit further includes a plug-in detection circuit, the signal input end of the plug-in detection circuit is connected to the other end of the first isolation unit, and the signal output end of the plug-in detection circuit is connected to the control circuit;

The plug-in detection circuit is used to detect the level signal of the access port of the video processing terminal; when the level signal is switched from an AC level signal to a DC level signal or from a DC level signal to an AC level signal, then cut off the The access port outputs the power supply of the image acquisition terminal.

The present invention provides a power supply circuit based on coaxial power supply technology, including a processing circuit of a video processing terminal, the processing circuit including a detection circuit and a control circuit; the detection circuit is used to detect the electrical parameters of the inlet of the video processing terminal ; The control circuit is used to control the power output of the access port to the image acquisition terminal on and off according to the electrical parameter. Wherein, the electrical parameter is a voltage value and/or a current value, and the access port is a port connected to an image collection terminal. It can be seen that the power supply circuit based on coaxial power supply technology can identify whether the image acquisition terminal connected to the video processing end supports coaxial power supply by detecting and analyzing the electrical parameters of the access port of the video processing end, and further judge whether it is necessary according to the analysis results. Power is supplied to the image acquisition terminal, which has high safety.

Description of drawings

1 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a first embodiment of the present invention;

2 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a second embodiment of the present invention;

3 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a third embodiment of the present invention;

4 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a fourth embodiment of the present invention;

5 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a fifth embodiment of the present invention;

6 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a sixth embodiment of the present invention;

7 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a seventh embodiment of the present invention;

Fig. 8 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to an eighth embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are exemplary only, and are not intended to limit the scope of the present invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concept of the present invention.

It should be noted that: hereinafter, Power Over Coaxia (POC, Power Over Coaxia) is a coaxial-based video, coaxial control, and power overlay technology. An analog camera is a camera whose output signal is an analog signal. ADC (Analog-to-Digital Converte) is an analog/digital converter or an analog/digital converter. POC cameras are analog cameras that support coaxial power supply. Non-POC cameras are ordinary analog cameras that do not support power over coaxial. Impedance is electrical impedance, which is a complex number with the real part of the resistance value and the imaginary part of the reactance value, and the unit is ohm.

Fig. 1 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a first embodiment of the present invention.

The power supply circuit based on coaxial power supply technology includes a processing circuit at the video processing end, the processing circuit includes a detection circuit and a control circuit, and the detection circuit and the control circuit are electrically connected;

The detection circuit is used to detect an electrical parameter of an access port of the video processing terminal, the electrical parameter is a voltage value and/or a current value, and the access port is a port for accessing an image acquisition terminal;

The control circuit is configured to control the power output of the access port to the image acquisition terminal on and off according to the electrical parameter.

The electric parameter refers to the electric parameter data of the electric equipment. When detecting the voltage value, you can use a voltage sensor, and when detecting the current value, you can use a current sensor, or directly use a voltage and current sensor, which can detect both the current value and the voltage value.

The current sensor is a detection device that can feel the information of the measured current, and can transform the information sensed by the detection into an electrical signal that meets certain standards or other required forms of information output according to certain rules, so as to meet the information requirements. transmission, processing, storage, display, recording and control requirements. According to different measurement principles, current sensors can be mainly divided into shunts, electromagnetic current transformers and electronic current transformers.

The voltage sensor is a detection device that can sense the information of the measured voltage, and can convert the information sensed by the detection into an electrical signal that meets certain standards or other required forms of information output to meet the information requirements. transmission, processing, storage, display, recording and control requirements. Voltage sensors are mainly divided into two types: DC voltage sensor and AC voltage sensor. The AC voltage sensor is an instrument that can convert the measured AC current (AC voltage) into a linearly proportional output DC voltage or DC current. A DC voltage sensor is an instrument that converts the measured DC voltage into a linearly proportional output DC voltage or DC current.

The access port is an interface for accessing the coaxial line. The coaxial cable is used to connect the video processing terminal and the image acquisition terminal powered by the coaxial cable, and the interface of the coaxial cable is preferably a BNC interface.

The power supply circuit based on coaxial power supply technology in the first embodiment of the present invention can identify whether the image acquisition terminal connected externally to the video processing end supports coaxial power supply by detecting and analyzing the electrical parameters of the access port of the video processing end, and according to the analysis result It is further judged whether it is necessary to supply power to the image acquisition terminal, which has high safety.

Fig. 2 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a second embodiment of the present invention. The power supply circuit based on the coaxial power supply technology in the second embodiment of the present invention adds a conduction unit that conducts the power output of the access port to the image acquisition terminal and cuts off the connection between the access port and the image acquisition terminal. Cut-off unit for power output.

Preferably, the second embodiment of the present invention is based on the first embodiment of the present invention, the control circuit includes a turn-on unit and a cut-off unit;

The conduction unit is configured to conduct the power output of the access port to the image acquisition terminal if the electric parameter belongs to the preset first electric parameter range;

The cutting unit is configured to cut off the power output of the inlet port to the image acquisition terminal if the electric parameter belongs to a preset second electric parameter range.

Preferably, the external image acquisition terminal is an analog camera, which can be distinguished according to whether it can support POC power supply. Analog cameras can be divided into two types: POC cameras and non-POC cameras. The preset first electrical parameter range corresponds to the preset electrical parameter range of the POC camera, and the preset second electrical parameter range corresponds to the preset electrical parameter range of the non-POC camera.

The above method is to analyze the absolute value of the electrical parameter, and by analyzing the absolute value of the electrical parameter, it can help to identify whether the externally connected image acquisition terminal supports POC power supply. After the electrical parameters are detected and analyzed, the access port can complete the identification of the external image acquisition terminal and determine whether external power supply is required.

Preferably, the second embodiment of the present invention is based on the first embodiment of the present invention, the control circuit includes a turn-on unit and a cut-off unit;

The conduction unit is configured to conduct the conduction of the access port to the The power output of the image acquisition terminal;

The cut-off unit is configured to cut off the access port to the image collection terminal when the power output of the image acquisition terminal is turned on and the change value of the electric parameter exceeds a preset stable electric parameter range. Collect the power output of the terminal.

The above method is to analyze the relative difference value of the electric parameter, and by analyzing the relative difference value of the electric parameter, it can help to identify whether the external image acquisition terminal supports POC power supply. The preset stable electrical parameter range can be set according to the measured data, and the measured data will vary according to the model of the external image acquisition terminal.

The power supply circuit based on coaxial power supply technology in the second embodiment of the present invention can distinguish the type of analog camera by detecting the difference in electrical parameters corresponding to POC cameras and non-POC cameras, and then automatically determine whether external power supply is required.

Fig. 3 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a third embodiment of the present invention. The power supply circuit based on the coaxial power supply technology in the third embodiment of the present invention describes the specific circuit structure of the processing circuit.

The third embodiment of the present invention On the basis of the first embodiment of the present invention, the processing circuit further includes a power supply circuit, a video processing circuit, a first isolation unit, a superposition circuit, a switch and a voltage dividing unit.

Wherein, the signal input end of the detection circuit is respectively connected to one end of the voltage dividing unit, the first inlet of the externally connected coaxial cable, the first fixed end of the switch, and one end of the first isolation unit. The signal output end is connected to the signal input end of the control circuit, the signal output end of the control circuit is connected to the moving end of the switch, the second fixed end of the switch is connected to one end of the superposition circuit, and the other end of the superposition circuit is connected to A power supply circuit, the other end of the voltage dividing unit is connected to the input power end for detection, and the other end of the first isolation unit is connected to the video processing circuit.

The power supply circuit based on the coaxial power supply technology in the third embodiment of the present invention is an automatic detection circuit, which can automatically identify the external analog camera and judge whether the external analog camera can supply power.

Fig. 4 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a fourth embodiment of the present invention. The power supply circuit based on the coaxial power supply technology in the fourth embodiment of the present invention describes the specific circuit structure of the processing circuit.

The fourth embodiment of the present invention is based on the third embodiment of the present invention, the first isolation unit is a capacitor C1, and the voltage dividing unit is a resistor R1.

Preferably, the signal input end of the detection circuit is respectively connected to one end of the resistor R1, the first inlet of the externally connected coaxial cable, the first fixed end of the switch, and one end of the capacitor C1, and the signal output of the detection circuit terminal is connected to the signal input terminal of the control circuit, the signal output terminal of the control circuit is connected to the moving end of the switch, the second fixed end of the switch is connected to one end of the superposition circuit, and the other end of the superposition circuit is connected to the power circuit , the other end of the resistor R1 is connected to the input power terminal for detection, and the other end of the capacitor C1 is connected to the video processing circuit.

The processing circuit can realize power supply and video processing, which can be subdivided according to functional modules: power supply circuit, used for POC power supply; superposition circuit, used to separate the power supply from the video signal; Whether external power supply is required; the detection circuit is used to detect the electrical parameters of the access port, and determine whether the external analog camera supports POC power supply through the size of the electrical parameters. VCC, that is, the input voltage value for detection (corresponding to the input power terminal for detection), is used to detect whether the power supply supporting POC is generally low voltage; R1, that is, the voltage dividing resistor for detection, is used for detecting the voltage dividing resistor used; C1 , used to isolate the DC power supply and input the video signal to the video processing circuit.

Preferably, the voltage value=the input voltage value for detection*the equivalent resistance value of the video signal processing circuit of the externally connected image acquisition terminal/(the equivalent resistance value+the voltage dividing resistance value for detection).

The power supply circuit based on the coaxial power supply technology in the fourth embodiment of the present invention is an automatic detection circuit, which can automatically identify the external analog camera and judge whether the external analog camera can supply power. Moreover, the selected electronic components are simple, which improves the compactness of the entire power supply circuit and reduces the cost of the power supply circuit.

Fig. 5 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a fifth embodiment of the present invention. The power supply circuit based on the coaxial power supply technology in the fifth embodiment of the present invention describes the specific circuit structure of the external image acquisition terminal circuit.

The fifth embodiment of the present invention is based on the fourth embodiment of the present invention, the second inlet of the externally connected coaxial cable is connected to the image acquisition terminal circuit.

The external image acquisition terminal is an analog camera, which can be distinguished according to whether it can support POC power supply. Analog cameras can be divided into two types: POC cameras and non-POC cameras. The following is the specific structure of the image acquisition terminal circuit corresponding to the POC camera.

Wherein, the image acquisition terminal circuit includes a coaxial power supply circuit, a video signal processing circuit, a power receiving circuit, a matching unit and a second isolation unit.

Preferably, one end of the coaxial power supply circuit is respectively connected to the second inlet of the external coaxial cable and one end of the matching unit, the other end of the matching unit is connected to one end of the second isolation unit, and the first The other ends of the two isolation units are connected to the video signal processing circuit, and the other ends of the coaxial power supply circuit are connected to the power receiving circuit.

The power supply circuit based on coaxial power supply technology in the fifth embodiment of the present invention is an intelligent circuit that automatically detects and provides power supply, can automatically identify the analog camera and judge whether the analog camera can be powered, and turn on or cut off the power supply according to the judgment result .

Fig. 6 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a sixth embodiment of the present invention. The power supply circuit based on the coaxial power supply technology in the sixth embodiment of the present invention describes the specific circuit structure of the external image acquisition terminal circuit.

The sixth embodiment of the present invention is based on the fifth embodiment of the present invention, the matching unit is a resistor R2. The resistance value of the resistor R2 is 75 ohms. The second isolation unit is a capacitor C2.

Wherein, one end of the coaxial power supply circuit is respectively connected to the second inlet of the external coaxial cable and one end of the resistor R2, the other end of the resistor R2 is connected to one end of the capacitor C2, and the other end of the capacitor C2 One end is connected to the video signal processing circuit, and the other end of the coaxial power supply circuit is connected to the power receiving circuit.

The POC camera can support the coaxial power supply analog camera, which can be subdivided into: power receiving circuit, used to obtain current from the coaxial power supply circuit and supply power to the POC camera; coaxial power supply circuit, used to When the power supply is transmitted to the powered circuit, it maintains high resistance to the video signal. The coaxial power supply circuit can be equivalent to a resistor (larger resistance value) before power supply; R2 and C2 are matching resistors and DC blocking capacitors. R3 is the equivalent resistance of the video signal processing circuit, which is generally smaller.

When the coaxial power supply video processing circuit is powered on, the control circuit turns on the switch, the coaxial power supply video processing circuit temporarily does not supply external power, and the capacitors C1 and C2 show high impedance to the DC level. Because the resistance on the coaxial line is small, it is ohm level and can be ignored. Therefore, the voltage V1 input by the detection circuit at this time is: V1=VCCxR4/(R4+R1).

The power supply circuit based on coaxial power supply technology in the sixth embodiment of the present invention is an intelligent circuit that automatically detects and provides power supply, can automatically identify the analog camera and judge whether the analog camera can be powered, and turn on or cut off the power supply according to the judgment result . Moreover, the selected electronic components are simple, which improves the compactness of the entire power supply circuit and reduces the cost of the power supply circuit.

Fig. 7 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to a seventh embodiment of the present invention. The power supply circuit based on the coaxial power supply technology in the seventh embodiment of the present invention describes the specific circuit structure of the external image acquisition terminal circuit.

The seventh embodiment of the present invention is based on the fourth embodiment of the present invention, the second inlet of the externally connected coaxial cable is connected to the image acquisition terminal circuit.

The external image acquisition terminal is an analog camera, which can be distinguished according to whether it can support POC power supply. Analog cameras can be divided into two types: POC cameras and non-POC cameras. The following is the specific structure of the image acquisition terminal circuit corresponding to the non-POC camera.

Wherein, the image acquisition terminal circuit includes a matching unit and a video signal processing circuit.

Wherein, one end of the matching unit is the second inlet of the externally connected coaxial cable, and the other end of the matching unit is connected to the video signal processing circuit.

Preferably, the matching unit is a resistor R2.

Wherein, the image acquisition terminal circuit includes a resistor R2 and a video signal processing circuit, one end of the resistor R2 is connected to the second inlet of the external coaxial cable, and the other end of the resistor R2 is connected to the video signal processing circuit. circuit.

The difference between the non-POC camera and the POC camera lies in the coaxial power supply circuit and the second isolation capacitor.

When the processing circuit is powered on, the control circuit turns on the switch, the processing circuit temporarily does not supply power to the outside, and the capacitor C1 presents a high impedance to the DC level. Because the resistance on the coaxial line (matching 75 ohms) is small, it is ohm level and can be ignored. Therefore, the voltage V2 input by the detection circuit at this time is: V2=VCCxR3/(R3+R1).

Comparing the sixth embodiment of the present invention with the seventh embodiment of the present invention, it can be seen that since the resistance values of R3 and R4 are greatly different, the voltage values of V1 and V2 are also greatly different.

In the power supply circuit based on coaxial power supply technology of the present invention, its internal detection circuit can use ADC conversion circuit or directly use schemes such as voltage comparator and current comparator to complete the POC camera and non-POC camera according to the large voltage difference. Distinguish, and output the result to the control circuit. After receiving the signal, the control circuit determines whether the switch needs to be turned on to supply power to the outside.

Fig. 8 is a structural block diagram of a power supply circuit based on coaxial power supply technology according to an eighth embodiment of the present invention. In the power supply circuit based on the coaxial power supply technology in the eighth embodiment of the present invention, a plug detection circuit for detecting a level signal during hot plug is added.

Hot-plugging (hot-plugging, Hot Swap) is hot-plugging, and the hot-plugging function allows users to take out and replace electronic components without shutting down the system or cutting off the power supply, thereby improving the system's timely recovery from disasters Power, scalability and flexibility.

Preferably, the eighth embodiment of the present invention is based on the first embodiment of the present invention, the processing circuit further includes a plug-in detection circuit, the signal input end of the plug-in detection circuit is connected to the other of the first isolation unit One end, the signal output end of the plug detection circuit is connected to the control circuit;

The plug-in detection circuit is used to detect the level signal of the access port of the video processing terminal; when the level signal is switched from an AC level signal to a DC level signal or from a DC level signal to an AC level signal, then cut off the The access port outputs the power supply of the image acquisition terminal.

The level signal is a voltage range, which stipulates that the output high level is >2.4V, and the output low level is <0.4V. At room temperature, the general output high level is 3.5V, and the output low level is 0.2V. Digital circuits usually only have high and low levels. The single-chip microcomputer can directly detect the level signal.

Sometimes, the user will replace the analog camera externally connected to the coaxial power supply video processing end without power interruption, that is, perform hot swapping of the analog camera. In the case where the power output of the external analog camera is turned on at the access port, if the POC camera is replaced with a non-POC camera, the non-POC camera will be burned; When the power output is cut off, if a non-POC camera is replaced with a POC camera, the POC camera will not supply power and have no video images. Therefore, when the external analog camera is replaced without power failure, the analog camera must be re-identified in order to determine whether the power output of the access port to the external analog camera can be turned on. In order to realize this function, it is necessary to monitor the level signal changes generated when the analog camera is hot-plugged. By detecting the level signal of the input port of the coaxial power supply video processing end, the identification function of the analog camera in the case of hot plugging can be realized.

For DC level, C1 is high impedance, but for AC video signal, C1 is low impedance. Inputting the voltage V3 signal to the plug-in detection circuit can avoid damage to the plug-in detection circuit caused by the superimposed higher voltage DC power supply. When hot plugging is not performed at the access port, such as the BNC port, the plug detection circuit can detect a stable video signal, that is, an AC signal. When hot plugging occurs at the BNC interface, during the time when the analog camera is unplugged, there is no external analog camera connected, the input of the plug detection circuit is a DC level signal, and the coaxial power supply can be identified through this difference The level signal generated by the hot plugging of the analog camera externally connected to the video processing circuit is used to complete the hot plugging detection. When the control circuit detects that hot plugging occurs, it cuts off the power output of the access port to the external analog camera, stops the power supply, and the detection circuit starts to work to re-detect the type of the analog camera.

The power supply circuit based on the coaxial power supply technology in the eighth embodiment of the present invention can automatically identify the external analog camera and determine whether the external analog camera can be powered. When the analog camera is hot plugged, the power supply scheme can be changed in real time, and the reliability and stability of the entire power supply circuit are improved on the premise of ensuring the connection of the analog camera.

For the various circuits mentioned above, those skilled in the art can select different circuit connection modes and components with different parameters to realize the corresponding functions of each circuit under the technical background of the technical solution according to the common knowledge, and no more examples are given here.

The present invention aims to protect a power supply circuit based on coaxial power supply technology, which can distinguish whether the image acquisition terminal externally connected to the video processing end supports coaxial power supply by detecting the electrical parameters of the access port of the video processing end, and further judge whether it is necessary Power supply to the image acquisition terminal, high security.

It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principle of the present invention, and not to limit the present invention. Therefore, any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present invention shall fall within the protection scope of the present invention. Furthermore, it is intended that the appended claims of the present invention embrace all changes and modifications that come within the scope and metesques of the appended claims, or equivalents of such scope and metes and bounds.

Claims (16)

1. A power supply circuit based on coaxial power supply technology, comprising a processing circuit at a video processing end, wherein the processing circuit includes a detection circuit and a control circuit, and the detection circuit and the control circuit are electrically connected; The detection circuit is used to detect an electrical parameter of an access port of the video processing terminal, the electrical parameter is a voltage value and/or a current value, and the access port is a port for accessing an image acquisition terminal; The control circuit is used to determine whether the image acquisition terminal externally connected to the video processing end supports coaxial power supply according to the electrical parameters, and controls the power output of the image acquisition terminal to be turned on or off by the access port. 2. The power supply circuit based on coaxial power supply technology according to claim 1, characterized in that, the control circuit comprises a conduction unit and a cut-off unit; The conduction unit is configured to conduct the power output of the access port to the image acquisition terminal if the electric parameter belongs to the preset first electric parameter range; The cutting unit is configured to cut off the power output of the inlet port to the image acquisition terminal if the electric parameter belongs to the preset second electric parameter range. 3. The power supply circuit based on coaxial power supply technology according to claim 1, characterized in that the control circuit comprises a conduction unit and a cut-off unit; The conduction unit is configured to conduct the conduction of the access port to the The power output of the image acquisition terminal; The cut-off unit is configured to cut off the access port to the image collection terminal when the power output of the image acquisition terminal is turned on and the change value of the electric parameter exceeds a preset stable electric parameter range. Collect the power output of the terminal. 4. The power supply circuit based on coaxial power supply technology according to claim 1, wherein the processing circuit further comprises a power supply circuit, a video processing circuit, a first isolation unit, a superposition circuit, a switch and a voltage dividing unit. 5. The power supply circuit based on coaxial power supply technology according to claim 4, characterized in that, the signal input end of the detection circuit is respectively connected to one end of the voltage dividing unit, the first inlet of the external coaxial cable, The first fixed end of the switch and one end of the first isolation unit, the signal output end of the detection circuit is connected to the signal input end of the control circuit, the signal output end of the control circuit is connected to the moving end of the switch, and the switch The second fixed end of the first isolation unit is connected to one end of the superposition circuit, the other end of the superposition circuit is connected to the power supply circuit, the other end of the voltage dividing unit is connected to the input power supply terminal for detection, and the other end of the first isolation unit is connected to the Video processing circuit. 6 . The power supply circuit based on coaxial power supply technology according to claim 4 or 5 , wherein the first isolation unit is a capacitor C1 . 7. The power supply circuit based on coaxial power supply technology according to claim 4 or 5, characterized in that the voltage dividing unit is a resistor R1. 8 . The power supply circuit based on coaxial power supply technology according to claim 5 , wherein the second inlet of the external coaxial cable is connected to the image acquisition terminal circuit. 9. The power supply circuit based on coaxial power supply technology according to claim 8, wherein the image acquisition terminal circuit includes a coaxial power supply circuit, a video signal processing circuit, a power receiving circuit, a matching unit and a second isolation unit . 10. The power supply circuit based on coaxial power supply technology according to claim 9, wherein one end of the coaxial power supply circuit is respectively connected to the second inlet of the external coaxial cable and one end of the matching unit The other end of the matching unit is connected to one end of the second isolation unit, the other end of the second isolation unit is connected to the video signal processing circuit, and the other end of the coaxial power supply circuit is connected to the power receiving circuit. 11. The power supply circuit based on coaxial power supply technology according to claim 9 or 10, characterized in that the matching unit is a resistor R2. 12 . The power supply circuit based on coaxial power supply technology according to claim 11 , wherein the resistance value of the resistor R2 is 75 ohms. 13. The power supply circuit based on coaxial power supply technology according to claim 9 or 10, wherein the second isolation unit is a capacitor C2. 14. The power supply circuit based on coaxial power supply technology according to claim 8, wherein the image acquisition terminal circuit includes a matching unit and a video signal processing circuit. 15. The power supply circuit based on coaxial power supply technology according to claim 14, characterized in that one end of the matching unit is connected to the second inlet of the external coaxial cable, and the other end of the matching unit is connected to The video signal processing circuit. 16. The power supply circuit based on coaxial power supply technology according to claim 4 or 5, characterized in that, the processing circuit further includes a plug-in detection circuit, and the signal input terminal of the plug-in detection circuit is connected to the first The other end of the isolation unit, the signal output end of the plug detection circuit is connected to the control circuit; The plug-in detection circuit is used to detect the level signal of the access port of the video processing end; when the level signal is switched from an AC level signal to a DC level signal or from a DC level signal to an AC level signal, then cut off the The access port outputs the power supply of the image acquisition terminal.

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