CN112153247B

CN112153247B - Video camera

Info

Publication number: CN112153247B
Application number: CN201910569853.XA
Authority: CN
Inventors: 陈媛; 王聪睿; 谷利飞
Original assignee: Hangzhou Hikvision Digital Technology Co Ltd
Current assignee: Hangzhou Hikvision Digital Technology Co Ltd
Priority date: 2019-06-27
Filing date: 2019-06-27
Publication date: 2022-02-01
Anticipated expiration: 2039-06-27
Also published as: CN112153247A

Abstract

According to the camera provided by the embodiment of the invention, the temperature in the camera is sensed by adopting the first thermistor, and when the temperature is sensed to be higher than or equal to the first preset temperature, the voltage output by the power supply is converted by the voltage processing chip to obtain the heating voltage; the first heating circuit induces the temperature of the image sensor or the processor chip through the second thermistor based on the heating voltage, and heats the image sensor and the processor chip based on the voltage provided by the power supply when the sensed temperature is higher than or equal to a second preset temperature. In the embodiment, the heating control of the image sensor and the processor chip is realized by adopting the hardware circuit, and compared with a software control mode, a single chip microcomputer is not required to be additionally introduced, so that the research and development period and cost are reduced, and the reliability of the heating control is improved.

Description

Video camera

Technical Field

The embodiment of the invention relates to the technical field of monitoring, in particular to a camera.

Background

When a network CAMERA (IP CAMERA, IPC) works in a low temperature environment, some components inside the network CAMERA may not work normally. Therefore, it is necessary to heat some components of the network camera, so as to provide a temperature environment for the camera to work normally.

In the prior art, a heating control is usually performed on a camera by adopting a software mode. Specifically, a software program burnt in the singlechip is used for controlling the heating switch. However, the above heating method needs to ensure the reliability of software and hardware of the single chip microcomputer, and also needs to introduce a flow of online burning control program on a production line, which results in long development period and high cost.

Disclosure of Invention

The embodiment of the invention provides a camera, which is used for improving the reliability of heating control of the camera and reducing the cost.

In a first aspect, a camera provided in an embodiment of the present invention includes: processor chip and image sensor, the camera still includes: the image sensor comprises a first thermistor, a voltage processing chip and two first heating circuits, wherein the two first heating circuits are respectively attached to the processor chip and the image sensor;

the voltage processing chip is connected with the first thermistor and a power supply, the first thermistor is used for sensing the temperature inside the camera, and when the first thermistor senses that the temperature inside the camera is higher than or equal to a first preset temperature, the voltage processing chip is used for receiving the voltage output by the power supply and carrying out voltage reduction processing on the voltage to obtain a heating voltage;

each first heating circuit is connected with the voltage processing chip and is used for receiving the heating voltage output by the voltage processing chip; each of the first heating circuits includes a second thermistor that senses a temperature of the processor chip or the image sensor based on the heating voltage;

each first heating circuit is also connected with the power supply, when the temperature sensed by the second thermistor is lower than or equal to a second preset temperature, the first heating circuit heats the processor chip or the image sensor based on the voltage output by the power supply, and when the temperature sensed by the second thermistor is higher than the second preset temperature, the first heating circuit stops heating the processor chip or the image sensor based on the voltage output by the power supply;

wherein the second preset temperature > the first preset temperature.

Optionally, the camera further includes: the memory card and a second heating circuit which is attached to the memory card are arranged;

the second heating circuit is connected with the voltage processing chip and used for receiving the heating voltage output by the voltage processing chip;

the second heating circuit comprises a third thermistor, and the third thermistor is used for sensing the temperature of the storage card; when the temperature sensed by the third thermistor is lower than or equal to a third preset temperature, the second heating circuit heats the memory card based on the heating voltage, and when the temperature sensed by the third thermistor is higher than the third preset temperature, the second heating circuit stops heating the memory card based on the heating voltage;

wherein the third predetermined temperature > the second predetermined temperature.

Optionally, the camera further includes: the lens glass and a third heating circuit which is attached to the lens glass;

the third heating circuit is connected with the voltage processing chip and used for receiving the heating voltage output by the voltage processing chip and heating the lens glass based on the heating voltage;

the third heating circuit comprises a temperature sensor, and the temperature sensor is used for sensing the temperature of the lens glass; when the temperature sensed by the temperature sensor is lower than or equal to a fourth preset temperature, or the sensed temperature is higher than or equal to a fifth preset temperature and lower than or equal to a sixth preset temperature, the third heating circuit heats the lens glass based on the heating voltage; when the temperature sensed by the temperature sensor is higher than the fourth preset temperature and lower than the fifth preset temperature, or the sensed temperature is higher than the sixth preset temperature, the third heating circuit stops heating the lens glass based on the heating voltage;

wherein the sixth preset temperature > the fifth preset temperature > the fourth preset temperature.

Optionally, each of the first heating circuits further comprises: the device comprises a first divider resistor, a first optical coupler, a relay and a first heating sheet;

the first voltage dividing resistor and the second thermistor are connected with the first optocoupler, the first optocoupler is connected with the relay, the relay is respectively connected with a power supply and the first heating sheet, and the first heating sheet is attached to the processor chip or the image sensor;

the second thermistor and the first voltage dividing resistor are used for dividing the heating voltage to obtain a voltage dividing result, and the first optical coupler responds to the voltage dividing result to be switched on or switched off so as to control whether the power supply heats the first heating sheet or not through the relay.

Optionally, the second heating circuit comprises: the second voltage dividing resistor, the second optical coupler, the MOS tube and the second heating sheet;

the third thermistor and the second voltage dividing resistor are connected with the second optical coupler, the second optical coupler is connected with the MOS tube, the MOS tube is connected with the second heating sheet, and the second heating sheet is attached to the storage card;

the third thermistor and the second voltage division resistor are used for dividing the heating voltage to obtain a voltage division result, and the second optical coupler responds to the voltage division result to be switched on or switched off so as to control whether the second heating sheet is heated based on the heating voltage or not through the MOS tube.

Optionally, the third heating circuit includes: the device comprises a first comparator, a second comparator, an MOS tube and a third heating sheet;

the temperature sensor is connected with the first comparator, the temperature sensor is also connected with the second comparator, the first comparator is connected with the MOS tube, the second comparator is connected with the MOS tube, the MOS tube is connected with the third heating sheet, and the third heating sheet is attached to the lens glass;

the first comparator is used for comparing the voltage signal corresponding to the temperature of the lens glass sensed by the temperature sensor with the voltage signal corresponding to the fifth preset temperature to obtain a first comparison result;

the second comparator is used for comparing the voltage signal corresponding to the temperature of the lens glass sensed by the temperature sensor with the voltage signal corresponding to the sixth preset temperature to obtain a second comparison result;

the MOS tube is turned on or off in response to the first comparison result and the second comparison result to control whether to heat the third heating sheet based on the heating voltage.

Optionally, the third heating circuit further includes: a third comparator and a fourth comparator;

the temperature sensor is connected with the third comparator, the temperature sensor is also connected with the fourth comparator, the third comparator is connected with the MOS tube, and the fourth comparator is connected with the MOS tube;

the third comparator is used for comparing the voltage signal corresponding to the temperature of the lens glass sensed by the temperature sensor with the voltage signal corresponding to the first preset temperature to obtain a third comparison result;

the fourth comparator is used for comparing the voltage signal corresponding to the temperature of the lens glass sensed by the temperature sensor with the voltage signal corresponding to the fourth preset temperature to obtain a fourth comparison result;

the MOS tube is turned on or off in response to the first comparison result, the second comparison result, the third comparison result and the fourth comparison result to control whether to heat the third heating sheet based on the heating voltage.

Optionally, the first thermistor is connected to a control port of the voltage processing chip, and the heating voltage output by the voltage processing chip is further input to the control port through a diode.

Optionally, the camera further includes a power monitoring circuit, and the power monitoring circuit is disposed between the voltage processing chip and the second and third heating circuits;

the power monitoring circuit includes:

the power monitoring chip is used for acquiring the current power of the camera;

and the voltage switch circuit is used for conducting when the current power is less than the preset power so that the second heating circuit and the third heating circuit can receive the heating voltage output by the voltage processing chip, and conducting switching-off when the current power is greater than or equal to the preset power so that the second heating circuit and the third heating circuit stop receiving the heating voltage output by the voltage processing chip.

Optionally, the camera further includes: a power supply loop;

the power monitoring chip is connected with the processor chip and is used for acquiring the preset power configured by the processor chip;

the power supply loop comprises at least one sampling resistor, the power monitoring chip is further connected with each sampling resistor, and the power monitoring chip is used for collecting sampling current flowing through the sampling resistors and determining the current power of the camera based on the sampling current.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a camera according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a camera according to another embodiment of the present invention;

FIG. 3 is a schematic diagram of a camera heating strategy provided by an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a camera according to another embodiment of the present invention;

fig. 5 is a schematic structural diagram of a start-up circuit according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a power monitoring circuit according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a first heating circuit according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a second heating circuit according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a third heating circuit according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

A network CAMERA (IP CAMERA, IPC) may need to work in various temperature environments as a monitoring device. In one possible scenario, the webcam needs to operate in a low temperature environment. A low temperature environment generally refers to an environment having a temperature ranging from-40 degrees to 0 degrees. When the network camera works in a low-temperature environment, part of components in the network camera may not work normally. For example: under a low-temperature environment, fog generated on the camera lens can affect the image quality; the SD card in the camera can generate phenomena of card dropping, packet loss and the like under a low-temperature environment; the SENSOR board and the platform main board of the camera can operate unstably in a low-temperature environment, and monitoring stability is affected.

In order to solve at least one of the above problems, embodiments of the present invention provide a camera, in which a hardware circuit is used to heat components of the camera, and compared with a software control method in the prior art, an additional introduction of a single chip is not required, so that a research and development period and cost are reduced, and reliability of heating control is improved.

The technical solution of the present invention will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

Fig. 1 is a schematic structural diagram of a camera according to an embodiment of the present invention. As shown in fig. 1, the camera of the present embodiment includes: the device comprises a power supply 11, a first thermistor 12, a voltage processing chip 13, a first heating circuit 14, an image sensor 15 and a processor chip 16.

The power supply 11 is used for supplying power to the devices in the camera and also for supplying power to the first heating circuit.

The video camera of the embodiment can be powered by a DC12V/AC24V/POE triple power supply. When the AC24V is powered, the power is firstly rectified into about output DC36V through a rectifier bridge, and then 12V is output through a voltage processing chip. When the POE supplies power, the POE firstly passes through the POE detection circuit and then outputs 12V through the network transformer chip. When the DC12V supplies power, the power is directly output at 12V after voltage stabilizing and filtering.

The working voltage of the camera is converted from 12V voltage to 5V voltage, and then from 5V to other working voltages such as 3.3V, 1.8V and 1.2V required by each device. Therefore, in the present embodiment, the first thermistor 12 and the voltage processing chip 13 are used to realize the conversion of the 5V operating voltage.

As shown in fig. 1, the voltage processing chip 13 is connected to the first thermistor 12 and the power supply 11, the first thermistor 12 is used for sensing the temperature inside the camera, and when the first thermistor 12 senses that the temperature inside the camera is higher than or equal to a first preset temperature, the voltage processing chip 13 receives the voltage output from the power supply 11 and performs voltage reduction processing on the voltage to obtain a heating voltage. In this embodiment, the heating voltage output by the voltage processing chip 13 is smaller than the voltage provided by the power supply 11. Illustratively, the voltage supplied by the power supply 11 is 12V, and the voltage processing chip 13 performs a voltage reduction process after receiving the 12V voltage, and converts the 12V voltage into a 5V heating voltage.

The first thermistor 12 may be disposed at any position in the camera as long as the first thermistor can sense the temperature inside the camera. In this embodiment, when the first thermistor 12 senses that the temperature inside the camera is higher than or equal to the first preset temperature, the voltage processing chip 13 starts the voltage conversion process. Illustratively, assuming that the startup temperature of the camera processor chip is-30 degrees, the first preset temperature is set to-30 degrees. When the camera is started in a low-temperature environment, and the temperature in the camera is lower than minus 30 ℃, the voltage processing chip does not start a voltage conversion process, namely the voltage processing chip does not output heating voltage, so that the first heating circuit does not work. When the temperature in the camera is higher than or equal to-30 ℃, the voltage processing chip starts a voltage conversion process, namely the voltage processing chip outputs heating voltage, so that the first heating circuit starts to work.

In this embodiment, the camera includes two first heating circuits 14, and the two first heating circuits may have the same structure or different structures. One of the first heating circuits 14 is attached to the image sensor 15 for heating the image sensor 15, and the other first heating circuit 14 is attached to the processor chip 16 for heating the processor chip 16.

As shown in fig. 1, the first heating circuit 14 is connected to the voltage processing chip 13, and the first heating circuit 14 can receive the heating voltage output from the voltage processing chip 13. When the first heating circuit 14 receives the heating voltage, the first heating circuit 14 turns on the heating function to heat the image sensor 15 and the processor chip 16. That is, the voltage conversion process of the voltage processing chip 13 realizes the heating control process of the first heating circuit 14.

As shown in fig. 1, the first heating circuit 14 is also connected to the power supply 11, and the first heating circuit 14 can perform heating based on the voltage output by the power supply 11. As can be understood, the image sensor 15 and the processor chip 16 are important components in the camera, have a large volume and need a stable temperature environment, and therefore, the heating efficiency of the image sensor 15 and the processor chip 16 can be ensured by heating with the voltage output by the power supply 11.

Assume that the camera's start-up operating temperature is set to-30 degrees. However, when the temperature of the camera is about-30 ℃, the processor chip and the image sensor of the camera cannot guarantee stable operation, and therefore, the processor chip and the image sensor need to be heated. The processor chip and the image sensor can normally and stably work at-15 degrees through verification, and therefore the corresponding critical temperature of the processor chip and the image sensor can be set to-15 degrees. That is, when the ambient temperature is lower than or equal to-15 degrees, the heating of the processor chip and the image sensor is started, and when the ambient temperature is higher than-15 degrees, the heating of the processor chip and the image sensor is stopped.

In the embodiment of the present application, the second thermistor is provided in the first heating circuit 14 attached to the image sensor 15, and the second thermistor can sense the temperature of the image sensor 15. When the temperature sensed by the second thermistor is lower than or equal to-15 ℃, heating the image sensor 15 based on the voltage output by the power supply; when the temperature sensed by the second thermistor is higher than-15 degrees, the heating of the image sensor 15 based on the voltage output from the power supply is stopped. Thereby enabling control of the heating strategy of the image sensor 15.

Similarly, a second thermistor is provided in the first heating circuit 14 disposed in close contact with the processor chip 16, and the second thermistor is capable of sensing the temperature of the processor chip 16. When the temperature sensed by the second thermistor is lower than or equal to-15 ℃, heating the processor chip 16 based on the voltage output by the power supply; when the temperature sensed by the second thermistor is higher than-15 degrees, the heating of the processor chip 16 based on the voltage output by the power supply is stopped. Thereby enabling control of the heating strategy of the processor chip 16.

The first heating circuit of the present embodiment may heat using a heat transfer principle. Specifically, the first heating circuit may include a heating plate, and the heating plate is in contact with the image sensor or the processor chip, so that heat of the heating plate is transferred to the image sensor or the processor chip, and heating of the image sensor or the processor chip is achieved.

Fig. 2 is a schematic structural diagram of a camera according to another embodiment of the present invention. As shown in fig. 2, on the basis of the embodiment shown in fig. 1, the camera of the present embodiment further includes: a second heating circuit 17, a memory card 18, a third heating circuit 19, and a lens glass 20.

The second heating circuit 17 is attached to the memory card 18, and is used for heating the memory card 18. The third heating circuit 19 is attached to the lens glass 20 and used for heating the lens glass 20.

As shown in fig. 2, the second heating circuit 17 is connected to the voltage processing chip 13, and is configured to receive the heating voltage output by the voltage processing chip 13 and heat the memory card based on the heating voltage.

The main role of the memory card in the camera is to store image or video data. In a low-temperature environment, phenomena such as card dropping of the memory card and data loss often occur, and therefore, it is necessary to heat the memory card in the low-temperature environment. Since the memory card is prone to the above problem in an environment below 0 degrees, the critical temperature corresponding to the memory card is set to 0 degrees in this embodiment.

Specifically, a third thermistor may be provided in the second heating circuit 17. The third thermistor is used for sensing the temperature of the memory card. When the temperature sensed by the third thermistor is lower than or equal to 0 ℃, the second heating circuit 17 heats the memory card based on the heating voltage; when the temperature sensed by the third thermistor is higher than 0 degrees, the second heating circuit 17 stops heating the memory card based on the heating voltage.

As shown in fig. 2, the third heating circuit 19 is connected to the voltage processing chip 13 for receiving the heating voltage output by the voltage processing chip 13; and heating the lens glass based on the heating voltage.

When the camera normally works, the internal components generate heat to cause large temperature difference between the inside and the outside, so that fog is easily generated on the lens glass, and the monitoring function of the camera is influenced. Therefore, the lens glass can be heated to remove the mist. In this embodiment, the following heating strategy is adopted for the lens glass: when the temperature of the lens glass is detected to be below 0 ℃, heating the lens glass to achieve the deicing and defogging effects; when the temperature of the lens glass is within the range of 0-10 ℃, the lens glass is still heated to achieve the defogging effect. Further, when the temperature of the lens glass is in the range of 40 to 70 ℃, the lens glass is still heated to remove fog caused by large temperature difference between the inside and the outside.

Specifically, the present embodiment provides a temperature sensor in the third heating circuit 19, and the temperature sensor is used for sensing the temperature of the lens glass. When the temperature sensed by the temperature sensor is lower than or equal to 10 degrees, or the sensed temperature is higher than or equal to 40 degrees and lower than or equal to 70 degrees, the third heating circuit 19 heats the lens glass based on the heating voltage; when the temperature sensed by the temperature sensor is higher than 0 degrees and lower than 10 degrees, or the sensed temperature is higher than 70 degrees, the third heating circuit 19 stops heating the lens glass based on the heating voltage.

Fig. 3 is a schematic diagram of a camera heating strategy provided by an embodiment of the present invention. The heating process of the camera after the start-up in a low temperature environment is described below with reference to fig. 3. As shown in fig. 3, after the camera is started, when the first thermistor senses that the internal temperature of the camera is higher than or equal to-30 ℃, the voltage processing chip starts voltage conversion from 12V to 5V, namely, 5V of heating voltage is output to the first heating circuit, the second heating circuit and the third heating circuit. Thereby, the first heating circuit, the second heating circuit, and the third heating circuit start heating.

When the second thermistor senses that the temperature of the image sensor or the processor chip is higher than or equal to-15 degrees, the first heating circuit stops heating the image sensor or the processor chip.

When the third thermistor senses that the temperature of the memory card is higher than or equal to 0 ℃, the second heating circuit stops heating the memory card.

When the temperature sensor senses that the temperature of the lens glass is higher than 10 ℃ and lower than 40 ℃, or the temperature of the lens glass is higher than 70 ℃, the third heating circuit stops heating the lens glass.

The camera provided by the embodiment realizes heating control of components in the camera by adopting the hardware circuit, and compared with a software control mode, the camera does not need to additionally introduce a single chip microcomputer, thereby reducing the research and development period and cost and improving the reliability of heating control.

In the prior art, the heating control of the components is realized by using software programs of a single chip microcomputer, and the heating control of a single temperature point is usually performed on each component. For example, the same critical temperature is set for a plurality of components, for example: the critical temperature of all the components to be heated is set to 0 ℃. And if the current environment temperature is lower than 0 ℃, triggering to heat all the components to be heated. Therefore, individualized heating control of different components cannot be satisfied. In addition, the condition that the power consumption of the camera is too low or too high often appears in the prior art, the heating effect is not good when the power consumption is too low, and the problems of too high internal temperature of the camera and energy waste are caused when the power consumption is too high.

In this embodiment, a heating circuit is provided for each component, for example: and heating circuits are respectively arranged for the image sensor, the processor chip, the storage card and the lens glass. Every heating circuit can carry out heating control according to the real-time temperature that detects and the critical temperature of this components and parts, can realize carrying out the heating control of differentiation to each components and parts for heating control is more nimble, thereby all provides accurate temperature environment for each components and parts, avoids appearing the camera consumption and crosses low or too high problem.

Fig. 4 is a schematic structural diagram of a camera according to another embodiment of the present invention. As shown in fig. 4, a power monitoring circuit 21 may be further included on the basis of the embodiment shown in fig. 2. The power monitoring circuit 21 is provided between the voltage processing chip 13 and the second and

third heating circuits

17 and 19.

In order to reduce the overall power consumption of the camera and avoid unnecessary energy waste caused by overhigh local heating temperature in equipment, a first heating circuit adopting 12V power supply, a second heating circuit adopting 5V heating voltage power supply and a third heating circuit of the camera do not need to be started simultaneously. It will be appreciated that since the memory card is located close to the motherboard in the camera, the temperature of the memory card may also rise with the motherboard heating. Similarly, the temperature of the lens glass may also rise along with the heating of the main board and/or the image sensor.

According to data statistical analysis, the overall power consumption of the network camera generally does not exceed 30W. Therefore, in the present embodiment, the power monitoring circuit 21 is added to the network camera. As shown in fig. 4, the voltage processing chip is further connected to a power monitoring circuit, the power monitoring circuit converts the 5V voltage output by the starting circuit into a 5V _ H voltage, and the 5V _ H voltage is used for supplying power to the second heating circuit and the third heating circuit.

The power monitoring circuit monitors the whole power consumption of the camera in real time, when the power consumption of the equipment is monitored to exceed 30W, on the premise that the normal function of the camera is guaranteed, the 5V voltage is stopped being converted into the 5V _ H voltage, namely, the second heating circuit and the third heating circuit are stopped being powered, the local heating temperature is prevented from being too high, and meanwhile, the power consumption of the network camera is reduced to a certain extent.

Specifically, the power monitoring circuit may include: power monitoring chip and voltage switch circuit.

The power monitoring chip is used for acquiring the current power of the camera; the voltage switch circuit is used for conducting when the current power is smaller than the preset power so that the second heating circuit and the third heating circuit can receive the heating voltage output by the voltage processing chip, and conducting switching-off when the current power is larger than or equal to the preset power so that the second heating circuit and the third heating circuit stop receiving the heating voltage output by the voltage processing chip.

In one possible implementation, the camera further includes: and the power monitoring chip is connected with the processor chip and is used for acquiring the preset power configured by the processor chip.

In the above embodiment, a circuit for converting 12V to 5V is referred to as a start circuit, that is, the start circuit includes the first thermistor and the voltage processing chip in the above embodiment. The structure of the start-up circuit and the structure of the power monitoring circuit are described below in conjunction with fig. 5 and 6, respectively.

Fig. 5 is a schematic structural diagram of a start-up circuit according to an embodiment of the present invention. Fig. 5 illustrates a case where the start-up circuit converts an input voltage of 12V into an operating voltage of 5V.

Assuming that the preset starting temperature of the network camera is-30 degrees, that is, when the ambient temperature reaches-30 degrees, the starting circuit starts to work, and the input voltage of 12V is converted into the starting voltage of 5V. Specifically, the thermistor R15 and the voltage dividing resistor RV7 form a voltage dividing circuit to control the EN pin voltage of the power supply chip UV1, so that the voltage conversion of the power supply chip is controlled. Wherein, the power chip UV 1V_ENThe minimum value is 1.2V, so the working voltage for turning on 5V conversion of the power chip UV1 is 1.2V.

The resistance value of the thermistor R15 is reduced along with the rise of the temperature, when the ambient temperature reaches-30 ℃, the resistance value of the thermistor R15 is 129K, and the resistance value of the voltage dividing resistor RV7 is 14.3K, so that the EN pin voltage of the power supply chip UV1 reaches 1.2V. With the rise of the temperature, the voltage drop of the EN pin of the power chip UV1 is higher than 1.2V, so that voltage conversion can be realized, and 5V working voltage is output to the camera platform and the heating circuit.

Optionally, as shown in fig. 5, a diode D35 is connected to the EN pin of the power chip UV1, so that once the camera is turned on for 5V voltage conversion, the conversion of the 5V voltage is not cut off regardless of the change of the ambient temperature, and the operation process of the camera after being turned on is not affected by the temperature.

Further, in fig. 5, CV2, CV3, and CV4 are input filter capacitors, and RV6 is a current limiting resistor. CV7, CV11, and CV12 are output filter capacitances. CV13 is the bypass capacitance of the base power supply inside the power chip. The AAM pin of the power supply chip UV1 is suspended, so that the power supply chip adopts the CCM working mode. The BST pin of the power supply chip UV1 forms an external bootstrap circuit of the power supply chip through an RC circuit connected in series externally, wherein the CV1 is a bootstrap capacitor and provides power for the BST pin of the power supply chip UV 1. LV1 is the inductance of BUCK circuit. The output of the power supply chip UV1 is adjusted through RV4 and RV8 according to a formula

It can be seen that when V is_OUTWhen 5V, RV4 and RV8 may be set to 39.2K and 7.5K, respectively.

Fig. 6 is a schematic structural diagram of a power monitoring circuit according to an embodiment of the present invention. As shown in fig. 6, the core of the power monitoring circuit is a power monitoring chip, which can adopt a chip with a working temperature range of-40 ℃ to 125 ℃ to meet the requirements of the camera on the working temperature environment.

In fig. 6, the power monitoring chip U105 communicates with the platform through an I2C serial port, and configures the maximum power consumption alarm value of the camera through the platform. The 12V working voltage provided by the power supply is divided into two paths of voltages which are respectively input to IN-and IN + pins of the power monitoring chip U105, so that the power monitoring chip U105 monitors the current value of the camera and calculates the current power according to the current value and the working voltage.

If the current power exceeds the preset power by 30W, the ALERT pin of the power monitoring chip U105 outputs a low level, the QH29 is closed, and the QH30 is not conducted, then the power monitoring circuit does not output a 5V _ H heating voltage to the second heating circuit and the third heating circuit. If the current power does not exceed the preset power by 30W, the ALERT pin of the power monitoring chip U105 does not output, the base of the QH29 is pulled to 3.3V, the QH29 is conducted, and the power monitoring circuit outputs 5V _ H heating voltage to the second heating circuit and the third heating circuit.

Further, as shown in fig. 6, CS135, C415, CH99, CH98, and CH97 are all filter capacitors, RH87, RH85, RP43, and RH77 are current limiting resistors, RH87 and CH95 are used for RC filtering, and R1596, R1597, and CS134 are used for filtering.

In this embodiment, the heating circuit can be implemented in the following two ways. In the first implementation mode, a thermistor and optocoupler implementation mode is adopted. In a second implementation, a temperature sensor plus a comparator implementation is used. Specifically, the image sensor, the processor chip, and the memory card may adopt the first implementation described above. The lens glass may adopt the second implementation manner described above.

More specifically, the first implementation manner described above can be subdivided into: the image sensor and the processor chip can adopt the control mode of adding the optical coupler and the relay by the thermistor, and the storage card can adopt the control mode of adding the MOS tube by the thermistor and the optical coupler.

In this embodiment, the heating circuit may be heated with high power, or may be heated with low power. Illustratively, the heating circuit corresponding to the image sensor and the processor chip is heated by using 12V voltage and 10W power, and the heating circuit corresponding to the SD card and the lens glass is heated by using 5V voltage and 4W power.

The structures of the first heating circuit, the second heating circuit, and the third heating circuit are described below with reference to fig. 7, 8, and 9, respectively.

Fig. 7 is a schematic structural diagram of a first heating circuit according to an embodiment of the present invention. As shown in fig. 7, the first heating circuit includes: the device comprises a voltage divider RP52, a thermistor RP16, an optocoupler OP3, a relay U18 and a heating plate JP 19.

Bleeder resistor RP52 and thermistor RP16 are connected with opto-coupler OP3, and opto-coupler OP3 is connected with relay U18, and relay U18 is connected respectively with power supply and heating plate JP19, and heating plate JP19 sets up with treater chip or image sensor laminating.

The thermistor RP16 and the voltage dividing resistor RP52 are used for dividing the heating voltage to obtain a voltage dividing result, and the optical coupler OP3 is switched on or switched off in response to the voltage dividing result so as to control whether the power supply supplies heat to the heating plate JP19 or not through the relay U18.

Among them, the optocoupler is also called an Optocoupler (OCEP), an opto-isolator, or an opto-coupler. The optical coupler takes light as a medium to transmit electric signals, has good isolation effect on input and output electric signals, and is high in conduction speed and isolation. By adopting the optical coupler to carry out heating control, the stability of the heating system can be improved.

Specifically, the resistance value of the voltage divider RP52 is determined according to the critical temperature of the processor chip or the image sensor, the resistance value of the thermistor RP16 increases with the decrease of the temperature, and the relationship between the current temperature and the critical temperature of the processor chip or the image sensor can be determined according to the voltage division results of the thermistor RP16 and the voltage divider RP 52. And if the current temperature is lower than or equal to the critical temperature, the optical coupler OP3 and the relay U18 are conducted to heat the heating sheet JP 19. The heat of the heating sheet JP19 transfers heat to the processor chip or the image sensor, thereby achieving heating of the processor chip or the image sensor.

The heating control process is described below, taking the critical temperature of the processor chip or the image sensor as-15 degrees as an example.

As shown in fig. 7, the resistance of the thermistor RP16 increases with the decrease of temperature, and when the temperature decreases to-15 degrees, the voltage division is performed on the 5V heating voltage through the voltage dividing resistor RP52 and the thermistor RP16, and the voltage division result is input to the reference pin 2 of the voltage regulator D37, so that the voltage value of the 2-pin clamp enable terminal of the voltage regulator D37 is greater than 2.5V, and then the 1-pin of the voltage regulator D37 outputs a stable 2V voltage. At this time, the optical coupler OP3 is turned on, the

pins

1 and 12 of the relay U18 are turned on by 3.3V _ H voltage, and the pin 4 of the relay U18 is switched to the pin 5, and the pin 9 is switched to the pin 8, so that the 12V voltage output by the power supply supplies power to the heating sheet JP19, and heating of the processor chip or the image sensor is started.

When the temperature of the processor chip or the image sensor rises to be higher than-15 ℃, the resistance value of the thermistor RP16 is reduced, and the voltage division result of the thermistor RP16 and the fixed resistor RP52 cannot reach the clamping start voltage of the voltage stabilizer D37, so that the pin 1 of the voltage stabilizer D37 outputs 5V voltage, the optical coupler OP3 is not conducted, the relay U18 is not conducted, and the heating of the processor chip or the image sensor is stopped.

Further, in fig. 7, RP53 and RP51 are current limiting resistors, CD22, CH100, and CH101 are filter capacitors, and D34 is an anti-reverse diode.

Fig. 8 is a schematic structural diagram of a second heating circuit according to an embodiment of the present invention. As shown in fig. 8, the second heating circuit includes: the device comprises a voltage divider RP44, a thermistor R90, an optical coupler OP1, a MOS tube QH4 and a heating plate JP 8.

Thermistor R90 and divider resistance RP44 are connected with opto-coupler OP1, and opto-coupler OP1 is connected with MOS pipe QH4, and MOS pipe QH4 is connected with heating plate JP8, and heating plate JP8 sets up with the storage card laminating.

The thermistor R90 and the voltage dividing resistor RP44 are used for dividing the heating voltage to obtain a voltage dividing result, and the optical coupler OP1 is switched on or switched off in response to the voltage dividing result so as to control whether the heating sheet JP8 is heated based on the heating voltage or not through the MOS tube QH 4.

Specifically, the resistance of the voltage divider RP44 is determined according to the critical temperature of the memory card, the resistance of the thermistor R90 increases with decreasing temperature, and the relationship between the current temperature and the critical temperature of the memory card can be determined according to the voltage division results of the thermistor R90 and the voltage divider RP 44. If the current temperature is lower than or equal to the critical temperature of the memory card, the optical coupler OP1 and the MOS tube QH4 are conducted to heat the heating sheet JP 8. Thus, the heating sheet JP8 transfers heat to the memory card, and heating of the memory card is achieved.

The heating control process will be described below by taking the critical temperature of the memory card as 0 degrees as an example.

As shown in fig. 8, the resistance of the thermistor R90 increases with the decrease of temperature, and when the temperature decreases to 0 degree corresponding to the critical temperature of the memory card, the voltage division of the heating voltage of 5V _ H is realized by the voltage dividing resistor RP44 and the thermistor R90, and the voltage division result is input to the 2 pin of the voltage regulator D1, so that the voltage value of the 2 pin clamp enable terminal of the voltage regulator D1 is greater than 2.5V, and then the 1 pin of the voltage regulator D1 outputs a stable 2V voltage. At this time, the optical coupler OP1 is turned on, and the MOS transistor QH4 is also turned on. The heating sheet JP8 is heated by a heating voltage of 5V _ H to heat the memory card.

When the temperature of the memory card rises to above 0 ℃, the resistance value of the thermistor R90 drops, and the voltage division result of the thermistor R90 and the voltage divider RP44 cannot reach the clamping start voltage of the voltage regulator D1, so that the pin 1 of the voltage regulator D1 outputs 5V voltage, the optical coupler OP1 is not conducted, the MOS tube QH4 is not conducted, and the memory card is stopped being heated.

Further, in the heating circuit shown in fig. 8, CH16 and CH18 are filter capacitors, RP42 is a current-limiting resistor of a collector of the optical coupler OP1, RP41 is a current-limiting resistor of a light emitting diode in the optical coupler OP1, and RP45 is a current-limiting resistor of a cathode input of the voltage regulator D1.

Fig. 9 is a schematic structural diagram of a third heating circuit according to an embodiment of the present invention, and as shown in fig. 9, the third heating circuit includes: temperature sensor UH4, first comparator UA7A, second comparator UA6B, MOS pipe QH5 and heating plate JP 7.

Temperature sensor UH4 is connected with first comparator UA7A, still is connected with second comparator UA6B, and first comparator UA7A is connected with MOS pipe QH5, and second comparator UA6B is connected with MOS pipe QH5, and MOS pipe QH5 is connected with heating plate JP7, and heating plate JP7 and lens glass laminating set up.

The first comparator UA7A is configured to compare a voltage signal corresponding to the temperature of the lens glass sensed by the temperature sensor UH4 with a reference power supply of the first comparator UA7A, so as to obtain a first comparison result.

The second comparator UA6B is configured to compare a voltage signal corresponding to the temperature of the lens glass sensed by the temperature sensor UH4 with a reference voltage of the second comparator UA6B, so as to obtain a second comparison result.

The MOS transistor QH5 is turned on or off in response to the first comparison result and the second comparison result to control whether to heat the heating sheet JP7 based on the heating voltage.

Specifically, the reference voltage (e.g., a voltage signal corresponding to a fifth preset temperature) of the first comparator UA7A and the reference voltage (e.g., a voltage signal corresponding to a sixth preset temperature) of the second comparator UA6B are determined according to the critical temperature of the lens glass. After the temperature sensor UH4 obtains the current temperature, the two comparators can determine the relationship between the current temperature and the critical temperature according to the relationship between the voltage signal corresponding to the current temperature and the reference voltage. If the current temperature is lower than the critical temperature, the MOS tube QH5 is controlled to be conducted, and when the MOS tube QH5 is conducted, the heating voltage heats the heating sheet JP7, so that the lens glass is heated.

The heating control process will be described below by taking as an example the case where the lens glass is heated in a temperature range of 40 to 70 degrees in the heating strategy.

As shown in fig. 9, when the temperature of the lens glass sensed by the temperature sensor UH4 is between 40 degrees and 70 degrees and is converted into a sampling voltage, the corresponding sampling voltage value is between 1.98V and 2.09V, and the sampling voltage value output by the temperature sensor UH4 decreases with the increase of the temperature. In fig. 9, the first comparator UA7A and the second comparator UA6B are used in the operating voltage range of-40 ℃ to 125 ℃, which meets the requirements of the operating environment of the device.

The first comparator UA7A sets a low temperature threshold of 40 degrees, where the low temperature threshold is 2.5V output by the voltage regulator D26 using a heating voltage of 5V _ H, and then a voltage of about 2.09V is obtained by dividing the voltage by two resistors R100 and R101. When the temperature sensed by the temperature sensor UH4 is lower than 40 degrees, the voltage value output by the temperature sensor UH4 is greater than 2.09V, and the first comparator UA7A is turned on. The voltage of 5V _ H is output to the gate of the MOS transistor QH5 through the diode DP6, the MOS transistor QH5 is turned off, and the heating voltage of 5V _ H does not heat the heater chip JP 7.

The second comparator UA6B sets a high temperature threshold of 70 degrees, which is set by R104 and R103. When the temperature sensed by the temperature sensor UH4 is higher than 70 degrees, the output voltage value is lower than 1.98V, and the second comparator UA6B is turned on. The voltage of 5V _ H is output to the gate of the MOS transistor QH5 through the diode D7, the MOS transistor is turned off, and the heating voltage of 5V _ H does not heat the heater chip JP 7.

Only when the temperature sensed by the temperature sensor UH4 is between 40 and 70 degrees, the output voltage value is between 1.98V and 2.09V, the first comparator UA7A and the second comparator UA6B are not conducted, so that the MOS transistor QH5 is conducted, the heating sheet JP7 is heated by the heating voltage of 5V _ H, and the lens glass is heated.

Further, in fig. 9, CH60, CH61, CA28, CH23, CH24, CH59, CH57, CH58, CA29, CH62, and CH63 are filter capacitors, R99, R102, R105, R106, RH54, RH25, RH53, and R107 are current limiting resistors, and FBH2 is a filter magnetic bead.

It can be understood that, when the heating strategy needs to heat within a temperature range of-30 degrees to 10 degrees, only a third comparator and a fourth comparator need to be added to the heating circuit shown in fig. 9, where the third comparator is used to compare the voltage signal corresponding to the temperature of the lens glass sensed by the temperature sensor with the voltage signal corresponding to-30 degrees of the critical temperature, so as to obtain a third comparison result; the fourth comparator is configured to compare a voltage signal corresponding to the temperature of the lens glass sensed by the temperature sensor with a voltage signal corresponding to a critical temperature of 10 degrees to obtain a fourth comparison result, so that the MOS transistor is turned on or off in response to the first comparison result, the second comparison result, the third comparison result, and the fourth comparison result to control whether the third heating sheet is heated based on the heating voltage. The corresponding heating principle is similar to the above temperature range of 40 to 70 degrees, and is not described in detail here.

The camera of this embodiment, through setting up the automatic control starting circuit based on thermistor, hardware circuit simple structure has guaranteed that the camera can start in low temperature environment to still avoided when low temperature environment during operation, the risk that thermistor cut off the platform power. Through setting up power monitoring circuit, cut off storage card heating circuit and lens glass heating circuit when reaching preset consumption, not only can realize the real-time supervision to the whole quick-witted consumption of network camera, can also avoid local heating temperature too high, reduce the whole machine consumption.

In each of the above examples, the unit "degree" of the critical temperature is in degrees centigrade (. degree. C.). The value of the critical temperature in each embodiment is only an exemplary illustration, and the value of the critical temperature in each embodiment is not specifically limited in the present invention, and it can be understood that a reasonable critical temperature may be selected according to different application scenarios.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A camera, comprising: processor chip and image sensor, characterized in that, the camera still includes: the image sensor comprises a first thermistor, a voltage processing chip and two first heating circuits, wherein the two first heating circuits are respectively attached to the processor chip and the image sensor;

wherein the second preset temperature > the first preset temperature.

2. The camera of claim 1, further comprising: the memory card and a second heating circuit which is attached to the memory card are arranged;

3. The camera of claim 2, further comprising: the lens glass and a third heating circuit which is attached to the lens glass;

4. The camera of claim 3, wherein each of the first heating circuits further comprises: the device comprises a first divider resistor, a first optical coupler, a relay and a first heating sheet;

5. The camera of claim 3, wherein the second heating circuit comprises: the second voltage dividing resistor, the second optical coupler, the MOS tube and the second heating sheet;

6. The camera of claim 3, wherein the third heating circuit comprises: the device comprises a first comparator, a second comparator, an MOS tube and a third heating sheet;

7. The camera of claim 6, wherein the third heating circuit further comprises: a third comparator and a fourth comparator;

8. The camera according to any one of claims 1 to 7, wherein the first thermistor is connected to a control port of the voltage processing chip, and the heating voltage output from the voltage processing chip is also input to the control port through a diode.

9. The camera of any one of claims 3 to 7, further comprising a power monitoring circuit disposed between the voltage processing chip and the second and third heating circuits;

the power monitoring circuit includes:

10. The camera of claim 9, further comprising: a power supply loop;