Power supply circuit and camera equipment

Abstract

A power supply circuit and camera equipment are used for protecting the safety of the camera equipment when the camera equipment is wrongly connected with a power supply. The power supply circuit in the camera equipment comprises an overcurrent protector, a first switch and a control module, the first end of the overcurrent protector is connected with a first power supply port of the camera device, and the second end is connected with the first end of the control module. The first end of the control module is used for being connected with other devices in the camera equipment, the second end is connected with the second power supply port, the third end is connected with the control end of the first switch, and the control module is used for controlling on and off of the first switch according to the voltage amplitude between the first power supply port and the second power supply port; the first end of the first switch is connected with other devices, and the second end is connected with the second power supply port. When the power supply circuit is connected with an alternating current power supply through the two power supply ports, the voltage at the two ends of the control module changes periodically, and the control module can control the first switch to be switched on and switched off based on the change condition of the voltage amplitude.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a power supply circuit and a camera device. Background Art

[0002] Currently, centralized power supply for multiple outdoor cameras typically requires a dedicated power supply box with multiple output ports for different voltages. For example, these output ports can output DC12V, AC220V, and AC24V, respectively. Each camera can be connected to the corresponding output port on the power supply box based on its power supply needs. Because DC and AC power lines are numerous and undifferentiated, it's common for cameras to be mistakenly connected to an AC port when connecting them, potentially damaging the device. Summary of the Invention

[0003] The present application provides a power supply circuit and a camera device, which are used to protect the safety of the camera device when the camera device is connected to an incorrect power source.

[0004] In a first aspect, embodiments of the present application provide a power supply circuit, which can be a power supply circuit within an imaging device. Multiple loads of the imaging device are connected to a power supply via the power supply circuit and receive electrical energy from the power supply via the power supply circuit. The power supply circuit can include an overcurrent protector, a first switch, and a control module.

[0005] In which, the first end of the overcurrent protector is connected to the first power supply port of the camera device, and the second end of the overcurrent protector is connected to the first end of the control module; the first end of the control module is used to connect to other devices in the camera device, the second end of the control module is connected to the second power supply port, and the third end of the control module is connected to the control end of the first switch, and the control module is used to control the conduction and shutdown of the first switch according to the voltage amplitude between the first power supply port and the second power supply port; the first power supply port and the second power supply port are used to be connected to the external power supply of the camera device; the first end of the first switch is used to connect to the other devices, and the second end of the first switch is connected to the second power supply port.

[0006] With the above-mentioned power supply circuit structure, the first switch is connected to the power transmission loop between the external power supply and other loads at the rear end. When the power supply circuit is connected to a DC power supply, the voltage difference between the two power supply ports is a fixed value, namely the output voltage of the DC power supply. When the power supply circuit is connected to an AC power supply, since the voltage amplitude and voltage direction of the AC power supply output both change periodically, the voltage difference between the two power supply ports also changes with the voltage amplitude of the AC power supply. Therefore, the control module can determine whether the connected power supply is an AC power supply or a DC power supply based on the voltage drop change at the two power supply ports when different power supplies are connected. When it is determined that the connected power supply is an AC power supply, the control module controls the first switch to turn off, thereby disconnecting the external power supply from other components within the camera device and protecting the safety of the camera device.

[0007] In one possible design, the first end of the first resistor is connected to the second end of the overcurrent protector, the second end of the first resistor is connected to the first end of the first capacitor and the control end of the first switch; and the second end of the first capacitor is connected to the second power supply port. With the above design, the first resistor and the first capacitor are connected in series to form an RC charging and discharging branch. When the camera device to which the power supply circuit belongs is mistakenly connected to an AC power supply, the voltage amplitude and voltage direction output by the AC power supply change periodically. Therefore, the charging time of the first capacitor within one cycle of the AC power supply is fixed. The charging amplitude of the first capacitor within this charging time cannot meet the amplitude requirement of the starting voltage of the first switch. The first switch is disconnected, causing the main circuit of the camera device to be in an open circuit state, thereby protecting the safety of the camera device.

[0008] In one possible design, the control module includes a sampling resistor and a controller. The first end of the sampling resistor is connected to the second end of the overcurrent protector, and the second end of the sampling resistor is connected to the second power supply port; the controller is used to control the conduction and shutdown of the first switch according to the voltage sampled at both ends of the sampling resistor. With the above design, since the amplitude and direction of the AC power supply change periodically, when the camera device to which the power supply circuit belongs is mistakenly connected to the AC power supply, the voltage amplitude at both ends of the sampling resistor connected in parallel with the AC power supply through the overcurrent protector will also change. The controller can obtain the voltage amplitude at both ends of the sampling resistor and control the conduction and shutdown of the first switch according to the potential difference at both ends of the sampling resistor.

[0009] In one possible design, when the camera device to which the power supply device belongs is connected to a DC power supply that can normally supply power, the voltage amplitude across the sampling resistor remains fixed. When the camera device to which the power supply circuit belongs is mistakenly connected to an AC power supply, the voltage amplitude across the sampling resistor will periodically change with the frequency of the AC power supply. Therefore, the controller obtains the voltage across the sampling resistor and, when it determines that the voltage difference at the first end of the sampling resistor is greater than a first preset threshold within a preset time period, it can be determined that the power supply connected to the camera device at this time is an AC power supply, and the first switch is controlled to turn off, thereby disconnecting the camera device from the power supply.

[0010] In one possible design, when the camera device to which the power supply circuit belongs is connected to a normally functioning DC power supply, the voltage amplitude across the sampling resistor remains fixed. When the camera device to which the power supply circuit belongs is mistakenly connected to an AC power supply, the voltage amplitude across the sampling resistor changes periodically with the frequency of the AC power supply. Therefore, a voltage amplitude greater than or equal to the normally functioning DC power supply can be set to a second preset threshold. When the controller determines that the voltage across the sampling resistor is greater than the second preset threshold, it can determine that the power supply connected to the camera device is an AC power supply and can control the first switch to turn off, thereby disconnecting the power supply from the camera device and protecting the safety of the camera device.

[0011] In one possible design, the controller includes a comparator, wherein a first input of the comparator is connected to a first end of the sampling resistor, a second input of the comparator is used to receive the second preset threshold value, and an output of the comparator is connected to a control end of the first switch. With the above design, when the camera device to which the power supply circuit belongs is connected to an AC power source, the voltages across the sampling resistor change periodically with the AC power. The comparator can compare the voltage at one end of the sampling resistor with a fixed third preset threshold value. For example, the rated voltage of the camera device can be used as the third preset threshold value. When the output voltage of the AC power source approaches a peak value, the voltage amplitude obtained by the sampling resistor may exceed the third preset threshold value. At this time, the level of the comparator output is reversed to control the first switch to turn off, thereby disconnecting the camera device from the power supply.

[0012] In one possible design, the power supply circuit further includes a diode, the anode of the diode being connected to the second end of the overcurrent protector, and the cathode of the diode being connected to the other device. With this design, when the camera device is connected to a DC power supply that can normally supply power, the first power supply port and the second power supply port are respectively connected to corresponding electrodes of the DC power supply. When the power supply ports are connected to the positive and negative poles of the power supply in reverse, the unidirectional conductivity of the diode can disconnect the main circuit between the camera device and the power supply, thereby protecting the safety of the power supply and the camera device.

[0013] In one possible design, the power supply circuit further includes a varistor, a first end of which is connected to the second end of the overcurrent protector, and a second end of which is connected to the second power port of the imaging device. With this design, by configuring the varistor with lightning protection, when the power supply box outputs surge energy to the imaging device due to lightning strikes or other reasons, the varistor activates to absorb the surge energy, thereby protecting the imaging device.

[0014] In one possible design, the power supply circuit further includes an inductor, a first end of which is connected to the second end of the overcurrent protector, and a second end of which is connected to the first end of the control module. With this design, when the power output from the power supply box to the camera fluctuates, the current flowing through the inductor cannot change suddenly, thereby stabilizing the operating current of the camera and improving the power supply quality of the camera.

[0015] In one possible design, the power supply circuit further includes a transient voltage suppressor diode, a first end of which is connected to the first end of the overcurrent protector, and a second end of which is connected to the first end of the first switch. With this design, when the power output from the power supply box to the camera fluctuates, the voltage across the capacitor cannot change suddenly, thereby stabilizing the power supply voltage to the camera and improving the power supply quality of the camera.

[0016] In a possible design, the overcurrent protector is a fuse.

[0017] In a second aspect, an embodiment of the present application provides a camera device, which includes a power supply circuit, a camera, and the power supply circuit provided in the first aspect of the present application and any possible design thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of a power supply box provided in an embodiment of the present application;

[0019] Figure 2 A schematic diagram of a power supply circuit provided in an embodiment of the present application Figure 1 ;

[0020] Figure 3 A schematic diagram of the structure of a control module provided in an embodiment of the present application Figure 1 ;

[0021] Figure 4 A schematic diagram of the structure of a control module provided in an embodiment of the present application Figure 2 ;

[0022] Figure 5A schematic diagram of the structure of a control module provided in an embodiment of the present application Figure 3 ;

[0023] Figure 6 A schematic diagram of a power supply circuit provided in an embodiment of the present application Figure 2 ;

[0024] Figure 7 A schematic diagram of a power supply circuit provided in an embodiment of the present application Figure 3 ;

[0025] Figure 8 A schematic diagram of a power supply circuit provided in an embodiment of the present application Figure 4 ;

[0026] Figure 9 A schematic diagram of a power supply circuit provided in an embodiment of the present application Figure 5 ;

[0027] Figure 10 A schematic diagram of a power supply circuit provided in an embodiment of the present application Figure 6 . DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operating methods in the method embodiments can also be applied to device embodiments or system embodiments. It should be noted that in the description of the present application, "at least one" refers to one or more, wherein "a plurality" refers to two or more. In view of this, "a plurality" can also be understood as "at least two" in the embodiments of the present application. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the previous and next associated objects are in an "or" relationship. In addition, it should be understood that in the description of the present application, words such as "first" and "second" are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

[0029] It should be noted that the control type switch in the embodiment of the present application can be one or more of various types of switching devices such as a metal oxide semiconductor field effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), a gallium nitride field effect transistor (GaN), a silicon carbide (SiC) power transistor, etc., and the embodiments of the present application will not list them one by one. Each switching device can include a first electrode, a second electrode and a control electrode, wherein the control electrode is used to control the on or off of the switching device. When the switching device is turned on, current can be transmitted between the first electrode and the second electrode of the switching device. When the switching device is turned off, current cannot be transmitted between the first electrode and the second electrode of the switching device. Taking MOSFET as an example, the control electrode of the switching device is the gate, the first electrode of the switching device can be the source of the switching device, the second electrode can be the drain of the switching device, or the first electrode can be the drain of the switching device and the second electrode can be the source of the switching device.

[0030] In order to facilitate understanding of the technical solution provided by this application, the application scenarios of the solution provided by this application are introduced below.

[0031] The solution provided by the present application can be applied to scenarios where multiple cameras are configured outdoors. At present, multiple cameras installed outdoors mostly use a centralized power supply method, that is, a power supply box is provided in the camera equipment use scenario, and the power supply box can be provided with an input port and multiple output ports. The input port of the power supply box can be connected to an AC power source, and multiple conversion circuits are provided inside the power supply box. Each conversion circuit is connected between the input port and an output port of the power supply box. The conversion circuit can convert the electric energy input from the AC power supply to the power supply box into AC or DC with different voltage amplitudes, and output it to the load connected to the back end through the output port connected to the conversion circuit. Therefore, the power supply box has multiple output ports of different output types and voltage amplitudes, so as to meet the power supply needs of different camera equipment. For example, see Figure 1 The figure shows a schematic diagram of the structure of the power supply box. Figure 1In the power supply box shown, the power supply box can have one input port and three output ports. The input port of the power supply box can be connected to an AC power source (mains) with an output voltage of AC220V. The output voltage specifications of the three output ports of the power supply box are DC12V, AC220V, and AC24V, respectively. Camera equipment that meets the above power supply requirements can be connected to the corresponding output ports and obtain the power required for operation from the power supply box. It should be noted that the output voltage specifications and the number of output ports of the power supply box are only for reference. In actual application, the output ports of the power supply box can also have other output voltage specifications. For example, the power supply box can also have an output port with an output voltage of AC48V. This application does not make specific restrictions here.

[0032] In actual use, the structure of the conversion circuit can be configured according to the function of the conversion circuit, and the function of the conversion circuit can be configured according to the voltage type and voltage amplitude of the input port and the output port. For example, if the output port connected to the conversion circuit outputs direct current, the conversion circuit needs to have a rectification function and a voltage regulation function. If the output port connected to the conversion circuit outputs alternating current, the conversion circuit needs to have a voltage regulation function or an electrical isolation function. The conversion circuit can use a circuit or chip that has the above functions commonly used in the industry, and this application does not introduce them one by one here.

[0033] use Figure 1 When the power supply box shown is used to power multiple cameras installed outdoors, the cameras can be connected to corresponding output ports within the power supply box according to their power needs. In this case, each output port of the power supply box functions as a power source for a camera, and the cameras can obtain the power they need from the connected output ports. Because multiple cameras in an outdoor installation are centrally powered by the power supply box, connecting multiple cameras to the output ports of the power supply box often results in a DC-powered camera being connected to an AC-powered output port on the power supply box, potentially damaging the cameras.

[0034] Based on this, an embodiment of the present application provides a power supply circuit and a camera device, which are used to protect the safety of the camera device when the camera device is connected to the wrong power source.

[0035] The following is an introduction to the solution provided by this application with reference to the accompanying drawings. Figure 2 The figure shows a schematic diagram of the structure of a power supply circuit provided by an embodiment of the present application. The power supply circuit can be set in a camera device that adopts DC power supply. When the power supply circuit is connected to the output port of the power supply box, the power supply circuit obtains power from the connected output port and supplies power to other devices in the camera device connected at the back end. The other devices may include one or more functional loads, including but not limited to camera modules. Figure 2As shown, the power supply circuit includes at least an overcurrent protector, a first switch K, and a control module. The overcurrent protector can be a fuse or other device with overcurrent protection function in the industry. Below, the power supply circuit provided in the embodiment of the present application is described using the overcurrent protector being a fuse FU as an example.

[0036] In which, the first end of the overcurrent protector is connected to the first power supply port of the camera device, and the second end of the overcurrent protector is connected to the first end of the control module; the first end of the control module is used to connect to other devices in the camera device, the second end of the control module is connected to the second power supply port, and the third end of the control module is connected to the control end of the first switch K. The control module is used to control the conduction and shutdown of the first switch K according to the voltage amplitude between the first power supply port and the second power supply port; the first end of the first switch K is used to connect to the other devices, and the second end of the first switch K is connected to the second power supply port.

[0037] In the present application, the first power supply port and the second power supply port within the power supply circuit can constitute the external interface of the camera device to which the power supply device belongs. The camera device can be connected to the power supply of the camera device through the first power supply port and the second power supply port and obtain the electrical energy output by the power supply. For example, if the camera device to which the power supply circuit belongs is powered by a DC power supply, the first power supply port can be connected to the positive electrode of the power supply of the camera device, and the second power supply port can be connected to the negative electrode of the power supply of the camera device.

[0038] In practical applications, taking the example of a camera device using a power supply box for centralized power supply, the camera device to which the power supply circuit belongs can be configured in a flexible and detachable manner, that is, the power supply box can be provided with a fixed interface, and the camera device can be connected to the power supply box through the fixed interface on the power supply box. For example, the power supply box can be provided with a power socket, and the camera device can be provided with a power plug, which can be connected to the first power port and the second power port. The camera device can insert the power plug into the power socket provided on the power supply box and obtain the power required for operation from the power supply box.

[0039] use Figure 2In the illustrated power supply circuit, when the camera device to which the power supply circuit belongs is connected to a power supply via a first power supply port and a second power supply port, if the power supply is a DC power supply required for normal operation of the camera device, the first power supply port is connected to the positive terminal of the DC power supply, and the second power supply port is connected to the negative terminal of the DC power supply. The voltage amplitude across the control module remains constant, equal to the output voltage of the DC power supply. If the power supply connected to the power supply circuit is an AC power supply, the first power supply port and the second power supply port are connected to the live and neutral wires of the AC power supply, respectively. Because the voltage direction and amplitude of the AC power supply output periodically change according to the frequency of the AC power, the voltage amplitude across the control module will also change with the voltage amplitude of the AC power supply. Based on the change in voltage amplitude when connecting the DC power supply and the AC power supply, the control module can determine the power type of the currently connected power supply and then control the on and off of a first switch K connected to the main power transmission circuit to protect the safety of the camera device.

[0040] Next, the process of the control module controlling the first switch K will be described in detail in conjunction with the structure of the control module.

[0041] In some embodiments, the control module may include an RC charge and discharge branch composed of multiple passive components, for example, see Figure 3 As shown, the control module may include a first resistor R1 and a first capacitor C1, the first end of the first resistor R1 is used to connect to the other components in the camera device, the second end of the first resistor R1 is connected to the first end of the first capacitor C1 and the control end of the first switch K, and the second end of the first capacitor C1 is connected to the second power supply port.

[0042] See also Figure 3As shown, the first resistor R1 and the first capacitor C1 are connected in series to form an RC charging and discharging branch, and the voltage at the first end of the first capacitor C1 is the control terminal voltage of the first switch K. When the first power supply port and the second power supply port in the power supply circuit are connected to the power supply, the first resistor R1, the first capacitor C1 and the overcurrent protector can form an energy transmission path of the power supply, and the power supply can charge the first capacitor C1 through the above energy transmission path. If the power supply connected to the power supply circuit is a DC power supply required for the normal operation of the camera device, the first capacitor C1 can be in a charging state before the first capacitor C1 is fully charged. The voltage across the first capacitor C1 will increase with the increase of the charging time. When the voltage across the first capacitor C1 is charged to the turn-on voltage Vgs of the first switch K, the first switch K is turned on to form an energy transmission path between the power supply and the rear-end load in the camera device. The power supply supplies power to multiple devices in the camera device through this energy transmission path to ensure that the camera device can operate normally. If the power supply connected to the power supply circuit is an AC power supply, the voltage amplitude and voltage direction of the AC power output by the AC power supply change periodically, which will cause the charging time of the first capacitor C1 to change accordingly. The charging voltage of the first capacitor C1 within one cycle of the AC power supply cannot meet the amplitude requirement of the turn-on voltage of the first switch K. The first switch K turns off and disconnects the power supply from other components in the camera device, thereby protecting the safety of the camera device.

[0043] In actual application, the RC charging and discharging branch formed by the first resistor R1 and the first capacitor C1 can be used when the camera equipment is mistakenly connected to any AC power supply in the power supply box. The charging voltage of the first capacitor C1 is less than the starting voltage of the first switch K. Therefore, the parameters of the first resistor R1 and the first capacitor C1 can be set according to the output voltage amplitude of the AC power supply in the power supply box. For example, taking the case where the camera device is mistakenly connected to the output port of the power supply box outputting AC24V, and the frequency of the AC power outputted from the output port to which the camera device is connected is 50Hz, the first resistor R1 can be a resistor with a resistance of 1000K, and the first capacitor C1 can be a capacitor with a capacitance of 100nF. The time constant of the RC charge-discharge circuit formed by the first capacitor C1 and the first resistor R1 is τ=R1*C1=0.1s. Taking the AC power supply with a voltage amplitude fluctuation of 25% as an example, the voltage input to the power supply circuit during one cycle of the AC power supply is Vin(t)=Umsin2πft=24*(1+0.25)*sin2π50t=30sin100πt. The charging voltage across the first capacitor C1 during one cycle of the AC power supply is A switch device with a startup voltage Vgs of 3V can be selected as the first switch K. The first switch K will be turned off when the voltage across the first capacitor C1 does not meet the voltage amplitude required for startup, thereby disconnecting the power supply from other components in the camera device and protecting the safety of the camera device.

[0044] It should be noted that Figure 3 The control module structure shown is for illustration only. In actual application, the control module may also include multiple capacitors and multiple resistors. Among them, multiple resistors can be connected in series or in parallel, and multiple capacitors can also be connected in series or in parallel. This application does not introduce them one by one here.

[0045] In some embodiments, the control module can also directly control the on and off of the first switch K by changing the voltage amplitude of the circuit when the power supply port is connected to different power sources. Figure 4 As shown, the control module may include a sampling resistor Rs and a controller, wherein the first end of the sampling resistor Rs is connected to the second end of the overcurrent protector, and the second end of the sampling resistor Rs is connected to the second power supply port; the controller may be connected to the sampling resistor Rs and the control end of the first switch K, respectively, and is used to control the conduction and shutdown of the first switch K according to the voltage sampled across the sampling resistor Rs.

[0046] See also Figure 4 As shown, when the first power supply port and the second power supply port are connected to the power supply, the sampling resistor Rs and the overcurrent protector constitute an energy transmission path of the power supply. The sampling resistor Rs can convert the current signal generated when the electric energy output by the above power supply passes through the energy transmission path into a voltage signal. The controller can obtain the above voltage signal and use the above voltage signal to determine the output voltage type of the power supply.

[0047] In a specific example, when the camera device is connected to a power supply via a first power port and a second power port, if the power supply connected to the camera device is a DC power supply required for normal operation, since the voltage amplitude output by the DC power supply is constant, the voltage amplitude across the sampling resistor Rs is also constant. Therefore, the voltage difference across the first end of the sampling resistor Rs or the voltage difference across the second end of the sampling resistor Rs detected within a preset time period is zero or close to zero. If the power supply connected to the camera device is an AC power supply, since the voltage amplitude and voltage direction output by the AC power supply vary according to a fixed period, the voltage amplitude across the sampling resistor Rs also varies with the voltage of the power supply. Therefore, the voltage difference across the first end of the sampling resistor Rs or the voltage difference across the second end of the sampling resistor Rs detected within the preset time period is greater than zero. When the controller detects that the power supply connected to the camera device is an AC power supply, it can determine that the power supply connected to the camera device is an AC power supply and control the first switch K to turn off, thereby disconnecting the power supply from other components within the camera device.

[0048] In practical applications, the preset duration can be set based on the cycle of the AC power supply. For example, since the voltage amplitude output by the AC power supply varies from 0V to peak value to 0V within each half cycle, the preset duration can be set to less than half of the half cycle of the AC power supply. In this way, the voltage amplitude obtained within the preset duration fluctuates between 0V and the peak value, and there are no repeated values, thereby improving the accuracy of the detection. Since the voltage amplitude output by the AC power supply is greater than 0V in the positive half cycle and less than 0V in the negative half cycle, the preset duration can also be set to greater than half a cycle of the AC power supply and less than one cycle of the AC power supply.

[0049] In actual use, the difference used to determine the type of connected power supply can be set to a first preset threshold. In the case of circuit stability and line loss, the first preset threshold can be set to any value greater than zero. In actual use, due to the fluctuation of the AC power supply connected to the input port of the power supply box and the limitations of the conversion accuracy of the internal components of the conversion circuit, the voltage amplitude of the AC power output from the output port of the power supply box may fluctuate. In order to ensure the accuracy of the detection results of the controller, the specific parameters of the first preset threshold can be set according to the voltage fluctuation amplitude caused by the above circuit. This application will not go into details here.

[0050] In a specific example, when the first power supply port and the second power supply port are connected to an AC power supply, if the power supply connected to the camera device is an AC power supply, since the voltage amplitude output by the AC power supply changes from 0V to peak value to 0V in each half cycle, the voltage across the sampling resistor Rs will be greater than the power supply voltage of the camera device. Based on the change in the voltage amplitude across the sampling resistor Rs when the AC power supply is connected, the controller can use a value greater than or equal to the rated voltage of the camera device as a second preset threshold, and when it is determined that the voltage across the sampling resistor Rs is greater than the second preset threshold, it is determined that the power supply connected to the camera device is an AC power supply, and the first switch K is controlled to turn off, thereby disconnecting the power supply from other components inside the camera device.

[0051] In actual use, if the power supply box in the camera equipment usage scenario is provided with multiple output ports for outputting DC power, and the voltage amplitudes output by the multiple output ports are different, the control module structure provided in the above embodiment of the present application can be adopted. When the power supply connected to the camera equipment is a DC power supply, but the voltage amplitude output by the DC power supply is greater than the rated voltage of the camera equipment, the control module can be used to disconnect the connection between the camera equipment and the power supply, thereby realizing the overload protection function of the camera equipment.

[0052] Using the control module provided in the above embodiment, the controller primarily controls the connection between the power supply and other components within the camera device by adjusting the operating state of the first switch K. The controller can be any one of a microcontroller unit (MCU), a central processing unit (CPU), and a digital signal processor (DSP). Specifically, the controller is provided with a pin connected to the first switch K. When the controller detects that the voltage amplitude across the sampling resistor Rs exceeds the rated voltage of the camera device, or that the voltage difference across the resistance sampled by the sampling resistor Rs within a preset time period is greater than a first preset threshold, it can be determined that the power supply connected to the camera device is an AC power source. The controller can stop sending control signals to the first switch K through the pin connected to the first switch K, or send a low-level signal to the first switch K, thereby controlling the first switch K to turn off, thereby protecting the safety of the camera device. When the controller detects that the voltage amplitude across the sampling resistor Rs is the rated voltage of the camera device, or the voltage difference of the voltage signal sampled by the sampling resistor Rs within a preset time period is less than or equal to a first preset threshold, it can be determined that the power supply connected to the camera device at this time is the DC power supply required for normal operation. The controller can send a high-level signal with an amplitude that meets the starting voltage requirement to the first switch K through the pin connected to the first switch K, thereby controlling the first switch K to be turned on, and the camera device can obtain electrical energy from the connected power supply and operate.

[0053] In actual application, in addition to the above components, the controller may also use other components. For example, the controller may use a comparator U, see Figure 5 As shown, the first input terminal of the comparator U is connected to the second terminal of the overcurrent protector, the second input terminal of the comparator U is used to receive the third preset threshold value, and the output terminal of the comparator U is connected to the control terminal of the first switch K. When the camera device is mistakenly connected to the AC power supply, the voltage output by the AC power supply will be greater than the rated voltage of the camera device. Therefore, the third preset voltage threshold value can be set to a value greater than or equal to the rated voltage of the camera device. When the camera device is connected to the power supply and the potential of the second terminal of the overcurrent protector is greater than the third preset threshold value when the power supply is connected, the comparator U meets the voltage conversion condition, and the level signal output to the first switch K changes, thereby controlling the first switch to be turned off. The third preset threshold value can be directly provided by an external power supply, or a conversion circuit can be configured within the power supply circuit to convert the voltage provided by the external power supply to the second preset threshold value.

[0054] In practical applications, the Figure 4 When the control module structure shown controls the working state of the first switch K, the voltage signal across the sampling resistor Rs is an analog signal, and the controller cannot directly process the analog signal. Therefore, an analog-to-digital converter needs to be set inside the controller, or an analog-to-digital converter needs to be set between the sampling resistor Rs and the controller to convert the analog voltage signal across the sampling resistor Rs into a digital signal.

[0055] It should be noted that Figure 4 The control module is set up using the sampling resistor Rs as an example. In actual use, other voltage sensors can also be used to obtain the voltage difference between the second end of the overcurrent protector and the second power supply port. This application does not make too many restrictions here.

[0056] Combined with the above description, Figures 3 to 5 The structure of the control module and the specific process of different control modules to detect the type of power supply connected are as follows: Figure 3 Taking the control module structure shown in FIG. 1 as an example, other components in the power supply circuit are introduced one by one.

[0057] In some embodiments, to prevent the power supply box from being damaged by lightning and causing damage to the overcurrent protector, see Figure 6As shown, the power supply circuit may also include a varistor RV with a surge protection function, one end of the varistor RV may be connected to the second end of the overcurrent protector, and the second end of the varistor RV may be connected to the second power supply port. When the power supply box is struck by lightning or other reasons cause surge energy to be present in the electric energy received by the power supply circuit, the varistor RV starts working to absorb the above-mentioned surge energy, thereby ensuring the safety of the camera equipment. In addition, since the varistor RV is in a high resistance state when the starting conditions are not met, when the camera equipment is mistakenly connected to an AC power supply, the current on the power transmission line can be reduced, which can effectively prevent the overcurrent protector from being damaged due to the large current, thereby ensuring the safety of the camera equipment.

[0058] In a specific example, since the sensitivity of the varistor RV is low, in order to quickly perform surge protection when surge energy appears in the circuit, a transient voltage suppressor diode (TVS) can also be set in the power supply circuit, see Figure 7 As shown, the first end of the TVS can be connected between the RC charge-discharge branch and other components within the camera device, in parallel with the RC charge-discharge branch. When the power supply circuit is connected to the power supply required for normal operation of the camera device, the first switch K is turned on, and the camera device draws power from the connected power supply and operates. During operation, if surge energy is present in the circuit line, the highly sensitive TVS can quickly activate and absorb the surge energy on the line, thereby protecting the camera device.

[0059] In some embodiments, in order to improve the power supply quality of the camera device, see Figure 8 As shown, the power supply circuit may further include an inductor L, the first end of the inductor L is connected to the second end of the overcurrent protector, and the second end of the inductor L is connected to the first end of the control module. When the current on the line fluctuates due to grid fluctuations or other reasons, the energy storage characteristics of the inductor will suppress the sudden increase in current and improve the stability of the power supply current of the circuit.

[0060] In some embodiments, in order to improve the power supply quality of the camera device, see Figure 9 As shown, the power supply circuit may also include a voltage-stabilizing capacitor C2, which can be connected between the TVS and other components within the camera device, and in parallel with the TVS. When the power supply circuit is connected to the power supply required for normal operation of the camera device, the first switch K is turned on, and the camera device draws power from the connected power supply and operates. During operation of the camera device, if the voltage on the line fluctuates due to power grid fluctuations or other reasons, the energy storage characteristics of the voltage-stabilizing capacitor C2 will suppress sudden voltage changes, thereby stabilizing the voltage received by the devices connected to the back end and improving the stability of the circuit's supply current.

[0061] In some embodiments, when the power supply connected to the power supply circuit is a DC power supply required for normal operation of the camera device, under normal circumstances, the first power supply port is connected to the positive pole of the DC power supply, and the second power supply port is connected to the negative pole of the DC power supply. In order to avoid the above two power supply ports being connected to the positive and negative poles of the power supply in reverse, which may cause damage to the circuit, see Figure 10 As shown, the power supply circuit may also include a diode D, the anode of which is connected to the second end of the overcurrent protector, and the cathode of which is connected to the other components. Based on the single-phase conductivity of the diode D, only when the first power supply port is connected to the positive pole of the DC power supply will the diode be turned on to form an energy transmission path between the DC power supply and other components in the camera device, thereby ensuring the power supply safety of the camera device. In actual use, in order to prevent the diode D from being damaged by breakdown due to high voltage when the camera device is mistakenly connected to an AC power supply, the anode of the diode D can be connected to the rear end of the control module, that is, the anode of the diode is connected to the first end of the control module, and the cathode is connected to other components in the camera device.

[0062] Based on the same inventive concept, an embodiment of the present application further provides a camera device, which may include a camera module and the aforementioned power supply circuit. The first power supply port and the second power supply port in the power supply circuit constitute an external interface of the camera device, and the camera device can be connected to one of the output ports on the power supply box through the aforementioned external interface. The manner in which the power supply circuit obtains electrical energy from the output port on the power supply box has been described in detail earlier in this application and will not be repeated here.

[0063] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations thereof may be made without departing from the spirit and scope of the present application. Accordingly, this specification and drawings are intended to be merely illustrative of the present application as defined by the appended claims and are intended to cover any and all modifications, variations, combinations or equivalents within the scope of the present application.

[0064] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A power supply circuit, characterized in that: Applied to a camera device, the power supply circuit includes: an overcurrent protector, a first switch and a control module; The first end of the overcurrent protector is connected to the first power supply port of the camera device, and the second end of the overcurrent protector is connected to the first end of the control module; The first end of the control module is used to connect to other components in the camera device, the second end of the control module is connected to the second power supply port, and the third end of the control module is connected to the control end of the first switch. The control module is used to control the conduction and shutdown of the first switch according to the voltage amplitude between the first power supply port and the second power supply port; the first power supply port and the second power supply port are used to connect to an external power supply of the camera device; The first end of the first switch is used to connect to the other device, and the second end of the first switch is connected to the second power supply port.

2. The circuit according to claim 1, wherein The control module includes: a first resistor and a first capacitor; The first end of the first resistor is connected to the second end of the overcurrent protector, and the second end of the first resistor is connected to the first end of the first capacitor and the control end of the first switch; The second end of the first capacitor is connected to the second power supply port.

3. The circuit according to claim 1, wherein The control module includes: a sampling resistor and a controller; The first end of the sampling resistor is connected to the second end of the overcurrent protector, and the second end of the sampling resistor is connected to the second power supply port; The controller is used to control the on and off of the first switch according to the voltage sampled at both ends of the sampling resistor.

4. The circuit according to claim 3, wherein: The controller is specifically configured to control the first switch to be turned off when it is determined that the voltage difference between the first end or the second end of the sampling resistor is greater than a first preset threshold within a preset time.

5. The circuit according to claim 3, wherein: The controller is specifically configured to control the first switch to be turned off when it is determined that the voltage across the sampling resistor is greater than a second preset threshold.

6. The circuit according to claim 3, wherein: The controller includes a comparator, a first input terminal of the comparator is connected to the first terminal of the sampling resistor, a second input terminal of the comparator is used to receive a third preset threshold, and an output terminal of the comparator is connected to the control terminal of the first switch.

7. The circuit according to any one of claims 1 to 6, characterized in that: The power supply circuit further includes a diode, an anode of the diode is connected to the second end of the overcurrent protector, and a cathode of the diode is connected to the other devices.

8. The circuit according to any one of claims 1 to 7, wherein: The power supply circuit also includes a varistor; The first end of the varistor is connected to the second end of the overcurrent protector, and the second end of the varistor is connected to the second power supply port of the camera device.

9. The circuit according to any one of claims 1 to 8, characterized in that: The power supply circuit further includes an inductor, a first end of the inductor is connected to a second end of the overcurrent protector, and a second end of the inductor is connected to a first end of the control module.

10. The circuit according to any one of claims 1 to 9, characterized in that: The power supply circuit further includes a transient voltage suppression diode, a first end of the transient voltage suppression diode is connected to the first end of the overcurrent protector, and a second end of the transient voltage suppression diode is connected to the first end of the first switch.

11. The circuit according to any one of claims 1 to 10, characterized in that: The overcurrent protector is a fuse.

12. A camera device, characterized in that: It comprises a camera module and a power supply circuit as claimed in any one of claims 1 to 11.

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