CN218243494U

CN218243494U - Shutdown circuit and shooting equipment thereof

Info

Publication number: CN218243494U
Application number: CN202222426543.2U
Authority: CN
Inventors: 陆声潘; 杨贵童
Original assignee: Insta360 Innovation Technology Co Ltd
Current assignee: Insta360 Innovation Technology Co Ltd
Priority date: 2022-09-13
Filing date: 2022-09-13
Publication date: 2023-01-06
Anticipated expiration: 2032-09-13

Abstract

The embodiment of the utility model provides a relate to electronic circuit technical field, disclose a shutdown circuit and shooting equipment. The shutdown circuit includes: the input end of the comparison circuit is connected with the trigger circuit, the output end of the comparison circuit is connected with the controlled end of the first power supply, the trigger circuit is used for outputting a shutdown signal when receiving a user trigger signal, and the comparison circuit is used for outputting a power-off signal to the controlled end of the first power supply when receiving the shutdown signal. The utility model discloses regard as detection part and control unit with the comparator to the first power of direct control can be independent of microcontroller's detection and control, realizes the function of shutting down, has avoided having improved the stability and the reliability of shutdown circuit because of microcontroller crashes and leads to the problem of unable shutdown.

Description

Shutdown circuit and shooting equipment thereof

Technical Field

The utility model relates to a shooting equipment technical field, in particular to shutdown circuit and shooting equipment thereof.

Background

With the continuous progress of technology, various consumer shooting devices used and involved in daily life are more and more. Such as headsets, display turntables, and handheld heads, among others. Among these consumer photographing devices, it is a common function for a user to implement power on/off control of the photographing device through a user interaction device such as a key or the like.

Various technical schemes are available to implement the above-mentioned function of controlling the shooting device to turn on/off. However, these solutions have their own drawbacks. For example, in a technical scheme that detection by a microcontroller is required, once a microcontroller or a single chip microcomputer and other devices cannot operate normally and a fault condition such as a halt occurs, the devices cannot respond to a power-on/power-off instruction of a user.

SUMMERY OF THE UTILITY MODEL

Therefore, it is necessary to provide a shutdown circuit and a shooting device thereof for solving the technical problem that the shooting device cannot be shut down after a microcontroller of the shooting device is halted in the conventional implementation scheme for controlling the startup/shutdown of the shooting device.

In order to solve the above technical problem, the utility model discloses one of them technical scheme that embodiment adopted is: a shutdown circuit. The shutdown circuit includes:

the trigger circuit is used for outputting a shutdown signal when receiving a user trigger signal;

the input end of the comparison circuit is connected with the trigger circuit, the output end of the comparison circuit is connected with the controlled end of the first power supply, and the comparison circuit is used for outputting a power-off signal to the controlled end of the first power supply when receiving the shutdown signal.

In one embodiment, the trigger circuit includes:

the key circuit is used for outputting a first control signal when triggered by a user;

and the controlled end of the trigger switch circuit is connected with the key circuit, the input end of the trigger switch circuit is connected with a preset level, the output end of the trigger switch circuit is connected with the input end of the comparison circuit, and the trigger switch circuit is used for being switched on when receiving the first control signal.

In one embodiment, the trigger circuit further comprises:

and the delay circuit is connected with the trigger switch circuit and is used for delaying the voltage change of the output end of the trigger switch circuit.

In an embodiment, the delay circuit includes a first capacitor, one end of the first capacitor is connected to the output end of the trigger switch circuit, and the other end of the first capacitor is grounded.

In one embodiment, the trigger switch circuit includes: a first resistor and a switching tube;

one end of the first resistor is connected with the second power supply, the other end of the first resistor is connected with the output end of the switch tube, the output end of the switch tube is connected with the input end of the comparison circuit, the input end of the switch tube is grounded, and the controlled end of the switch tube is connected with the key circuit.

In one embodiment, the comparison circuit includes: a second resistor, a third resistor and a comparator;

one end of the second resistor is connected with a second power supply, the other end of the second resistor is connected with one end of the third resistor, and the other end of the third resistor is grounded; and the common end of the second resistor and the third resistor is connected with the first input end of the comparator, the second input end of the comparator is connected with the trigger circuit, and the output end of the comparator is connected with the controlled end of the first power supply.

In one embodiment, the comparison circuit further comprises:

and one end of the fourth resistor is connected with the second power supply, and the other end of the fourth resistor is connected with the output end of the comparator.

In one embodiment, the shutdown circuit further includes:

the input end of the isolation circuit is connected with the output end of the comparison circuit, and the output end of the isolation circuit is connected with the controlled end of the first power supply; alternatively, the first and second electrodes may be,

and the cathode of the unidirectional conduction circuit is connected with the output end of the comparison circuit, and the anode of the unidirectional conduction circuit is connected with the controlled end of the first power supply.

In order to solve the above technical problem, the utility model discloses another technical scheme that embodiment adopted is: a photographing apparatus. The photographing apparatus includes: a first power supply and a shutdown circuit as described above; the shutdown circuit is connected with the controlled end of the first power supply.

In some embodiments, the power supply comprises: a battery for providing the power supply; the input end of the power management chip is connected with the battery, the output end of the battery management chip is used for outputting a power supply, the controlled end of the power management chip is connected with the shutdown circuit, and the power management chip is used for stopping outputting the power supply when receiving the power-off signal; and/or the input end of the second power supply switch circuit is connected with the battery, the output end of the second power supply switch circuit is used for outputting a power supply, the controlled end of the second power supply switch circuit is connected with the shutdown circuit comparison circuit, and the second power supply switch circuit is used for being disconnected when receiving the power-off signal.

The utility model discloses technical scheme receives user trigger signal and output shutdown signal through setting up trigger circuit, sets up comparison circuit again and detects shutdown signal to the controlled end of output outage signal to first power, with the outage of control first power, realize the shutdown of shooting equipment. The utility model discloses regard as the controlled end of shutdown detection part (detecting shutdown signal) and control unit (the output lug connection of comparison circuit) to the first power with the comparison circuit, need not pass through microcontroller's control, be independent of microcontroller's detection and control, just realized the function of shutting down, solved traditional shutdown scheme in, the unable scheduling problem of shutting down of equipment that microcontroller halted and leads to has improved the stability and the reliability of shutdown circuit.

Drawings

One or more embodiments are illustrated in corresponding drawings which are not intended to be limiting, in which elements having the same reference number designation may be referred to as similar elements throughout the drawings, unless otherwise specified, and in which the drawings are not to scale.

Fig. 1 is a schematic diagram of a shooting device provided by an embodiment of the present invention;

fig. 2a is a schematic diagram of a shooting device provided by an embodiment of the present invention, which shows one specific implementation of a power supply in the shooting device;

fig. 2b is a schematic diagram of a shooting device provided by the embodiment of the present invention, which shows another specific implementation of a power supply in the shooting device;

fig. 3 is a schematic diagram of a shutdown circuit according to an embodiment of the present invention;

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

fig. 5a is a schematic diagram of a shutdown circuit provided by the embodiment of the present invention, illustrating a situation that a switching tube is turned off;

fig. 5b is a schematic diagram of a shutdown circuit provided by the embodiment of the present invention, illustrating a situation that the switch tube is closed;

fig. 6 is a schematic circuit diagram of a shutdown circuit provided by an embodiment of the present invention;

fig. 7 is a table of different response times provided by the embodiment of the present invention, which shows the corresponding relationship between the response time and the first capacitance value, the first resistance value, the second resistance value, and the third resistance value.

Detailed Description

The present invention is described in detail below with reference to specific embodiments, and it should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

It is to be noted that, unless otherwise explicitly specified or limited, the terms "central," "longitudinal," "lateral," "upper," "lower," "vertical," "horizontal," "inner," "outer," and the like as used herein are intended to refer to orientations or positional relationships illustrated in the accompanying drawings, and are intended to facilitate description of the present invention and to simplify description, but are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the present invention. The terms "mounted," "connected," "secured," and the like are to be construed broadly and may include, for example, fixed connections, removable connections, or integral connections; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. Furthermore, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated; thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; "plurality" means two or more; "and/or" includes any and all combinations of one or more of the associated listed items. The specific meaning of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

Fig. 1 is a functional block diagram of a shooting device according to an embodiment of the present invention. The shooting device may determine its specific implementation form according to different practical application scenarios, for example, a handheld pan-tilt, a panoramic camera, a thumb camera, a motion camera, and the like. The embodiment of the utility model provides a do not prescribe a limit to its concrete realization. As shown in fig. 1, the photographing apparatus includes: shutdown circuit 10, interactive device 20, first power supply 30, and load 40.

The shutdown circuit 10 is a circuit capable of detecting an action instruction of a user to some specific interactive devices set on the shooting device and correspondingly controlling the shooting device to shutdown.

In this embodiment, the shutdown is a technical concept opposite to the startup, and means that the shooting device is switched to an operation state in which most or all of the functional modules are deactivated and the power consumption is significantly reduced or is close to zero in an operation state in which most or all of the functional modules are activated and corresponding functions can be operated in response to a user instruction at any time.

The interaction device 20 is a component that can be used to sense user actions and form corresponding user trigger signals. The touch type, press type or any other suitable type of input device can be selected and adopted according to the needs of the actual situation, and a corresponding user trigger signal is formed.

The first power source 30 is an energy source that can continuously supply electric power. It may specifically be chosen to use any suitable type of implementation, such as a rechargeable battery, to provide the required target voltage, as the case may be. In other embodiments, the first power source 30 may be external, and may be powered through, for example, a USB interface or the like.

The load 40 refers to any type of circuit module in the photographing apparatus that needs to consume power to perform a corresponding function, including but not limited to a main controller. Which corresponds to the operating state of the photographing apparatus. When the photographing apparatus is in an operating state, the load 40 draws and consumes power from the power supply. After shutdown, the load 40 stops operating and switches to the off state.

During actual use, when the photographing apparatus is in an operating state, the user may operate (e.g., press) the interaction apparatus 20, thereby forming a user trigger signal. When detecting the user trigger signal, the shutdown circuit 10 may correspondingly output a power-off signal to the controlled terminal of the first power supply 30, so that the first power supply 30 stops supplying power to the load 40, thereby implementing shutdown of the shooting device.

In some embodiments, as shown in fig. 2a, the first power supply 30 may include: a battery 31 and a battery management chip 32. The input end of the battery management chip 32 is connected to the battery 31, and after acquiring the power from the battery 31 and converting it into a suitable target voltage (for example, 3.3V or 5V), the output is provided to a corresponding load as a power supply of the load 40. One pin of the battery management chip 32 may be used as a controlled terminal of the first power supply 30, and is connected to the shutdown circuit 10, so that the battery management chip 32 can receive the power-off signal and further cut off the power supply of the load 40, thereby completing shutdown of the shooting device.

In other embodiments, as shown in FIG. 2b, the first power supply 30 may further include a power switch circuit 33. In the present embodiment, the term "switch circuit" is used to indicate an electronic device capable of correspondingly disconnecting or connecting lines according to different control signals. Depending on its function, it may have a controlled terminal, an input terminal, and an output terminal. Each switching circuit can determine whether the current is allowed to flow between the input end and the output end through the electric signal received by the controlled end.

The power switch circuit 33 is provided on a power supply line between the battery 31 and the load 40. The controlled end of the power supply is used as the controlled end of the first power supply and is connected with the shutdown circuit, so that the shooting equipment is shut down by disconnecting the power supply circuit under the condition of receiving the power failure signal.

The switching circuit can specifically select and use appropriate devices according to the needs of actual situations, including but not limited to MOS transistors, triodes, and other similar electronic devices. For example, the power switching circuit 33 may be implemented by a MOS transistor. The grid of the MOS tube is used as a controlled end, and the source electrode and the drain electrode of the MOS tube are respectively used as an input end and an output end.

Fig. 3 is a functional block diagram of a shutdown circuit according to an embodiment of the present invention. The shutdown circuit 10 can be applied to the photographing apparatuses shown in fig. 1 and 2.

As shown in fig. 3, in an embodiment, the shutdown circuit 10 may include: a trigger circuit 110 and a comparison circuit 120.

The trigger circuit 110 is configured to output a shutdown signal when receiving a user trigger signal. The trigger circuit may be implemented by combining a physical key with a diode or a switching tube, where the physical key triggers the diode to be in a reverse cut-off state or a forward cut-on state to output or not output a shutdown signal, or the physical key triggers the switching tube to be in a cut-on state or a cut-off state to output or not output a shutdown signal, and the specific circuit is not described herein again. In the present embodiment, the terms of the "user trigger signal" and the "power-off signal" are only used to distinguish the functions of the signals, and are not used to limit the specific implementation thereof. Both can be set according to the needs of actual conditions and adopt proper signal forms. Those skilled in the art can select the appropriate trigger circuit 110 to use according to the specific user trigger signal and the shutdown signal.

The comparator circuit 120 has an input for receiving a shutdown signal and an output for providing a power-down signal. The input terminal is connected to the trigger circuit 120, and the output terminal is connected to the controlled terminal of the first power supply. The comparison circuit 120 can perform a comparison detection function, and when receiving the shutdown signal, outputs a power-off signal to the controlled terminal of the first power supply 30, so that the first power supply 30 stops outputting the power supply to supply power to the load. In particular, the comparison circuit may be built by an integrated comparator chip or using discrete elements such as switching tubes. The comparison circuit 120 may have a non-inverting input and an inverting input. One input end is connected with the shutdown signal, and the other input end is connected with a low level or a high level according to the factors of the non-inverting input end or the inverting input end, the level of the shutdown signal and the like. Taking the shutdown signal as a low level and accessing the inverting input terminal of the comparison circuit as an example, the other input terminal is a non-inverting input terminal and can access a high level, so that the comparison circuit outputs a high level signal as a power-off signal when the level of the non-inverting input terminal is greater than that of the inverting input terminal. Other cases are similar and will not be described herein.

The utility model discloses technical scheme receives user trigger signal and output shutdown signal through setting up trigger circuit, sets up comparison circuit again and detects shutdown signal to the controlled end of direct output outage signal to first power, with the outage of control first power, realize shooting equipment's shutdown. The utility model discloses regard as the controlled end of shutdown detection part (detecting shutdown signal) and control unit (the output lug connection of comparison circuit) to the first power with the comparison circuit, need not pass through microcontroller's control, be independent of microcontroller's detection and control, just realized the function of shutting down, solved traditional shutdown scheme in, the unable scheduling problem of shutting down of equipment that microcontroller halted and leads to has improved the stability and the reliability of shutdown circuit.

In some embodiments, with continued reference to fig. 3, the triggering circuit 110 may include: a key circuit 111 and a trigger switch circuit 112.

The key circuit 111 is a circuit module capable of performing the functions of detection and acquisition, and is used for outputting a first control signal when the interactive device is triggered by a user (for example, a key is pressed). The specific setting may be determined according to the actual conditions such as the specific form of the first control signal that needs to be generated, the specific used interaction device, and the like, which are not described herein again.

The trigger switch circuit 112 is a circuit block capable of providing the comparator circuit 120 with a required shutdown signal in the presence of the first control signal. As described above, it may be substantially equivalent to a switch structure having at least a controlled terminal, an input terminal, and an output terminal. The trigger switch circuit can control the connection or disconnection between the input end and the output end according to the change of an electric signal input by the controlled end.

In this embodiment, the key circuit 111 may be connected to a controlled terminal of the trigger switch circuit 112, and the on/off between the input terminal and the output terminal of the trigger switch circuit 112 is controlled by inputting the first control signal. The input terminal of the trigger switch circuit 112 is connected to the input terminal of the comparison circuit 120, and the output terminal of the trigger switch circuit 112 is connected to a node having a specific voltage to switch on the predetermined level. Therefore, the trigger switch circuit 112 can be turned on under the control of the first control signal, so that the input end of the comparison circuit generates a level signal change (i.e. a shutdown signal).

For example, the output terminal of the trigger switch circuit 112 may be connected to a second power source having a preset voltage. When the trigger switch circuit 112 is turned on, the level of one of the input terminals of the comparison circuit can be pulled up, so that the level between the two input terminals of the comparison circuit is changed. Alternatively, the output of the trigger switch circuit 112 may also be grounded (e.g., the zero potential point of the system). When the trigger switch circuit 112 is turned on, the level of one of the input terminals of the comparison circuit can be pulled down, and the effect of changing the level between the two input terminals of the comparison circuit is also achieved.

Specifically, the second power supply providing the preset level and the first power supply may be the same power supply, and the adaptive setting may be, for example, the first power supply is converted into the second power supply through voltage reduction or other voltage processing manners. In other implementations, the second power source may be a port that is capable of maintaining a constant power supply state, different from the first power source, for a specific target voltage. Any suitable type of power supply implementation mode can be specifically selected, and only the stable direct-current target voltage can be continuously provided. The specific target voltage may be set according to the actual requirement, for example, 2V, and is not particularly limited herein.

With continued reference to fig. 3, in some embodiments, the trigger circuit 110 may further include an additional delay circuit 113.

The delay circuit 113 is connected to the trigger switch circuit 112, and can be used to delay a voltage change occurring at an input terminal of the switch circuit. The delay circuit can be an RC delay circuit, that is, a delay circuit is built up by a resistor and a capacitor. The delay circuit can also be realized by one or a series of inverters, and the specific implementation of the delay circuit is not limited herein.

In the present embodiment, the term "delay" is used to indicate a function of extending the time required for the level signal to change. In other words, with the additional delay circuit 113, it takes a while for the trigger switch circuit 112 to respond to the user trigger action to provide the required shutdown signal for the comparison circuit 120.

Compared with the traditional method of realizing delayed shutdown through software control of a microcontroller, the method adopts a hardware circuit to build, does not depend on the microcontroller, and simplifies the control strategy. And on the basis of the problem that the product can not be shut down when the microcontroller is halted, the delayed shutdown realized by the hardware circuit is provided, so that the power-off signal of the shutdown circuit can not be sent out due to short or instant touch or pressing action, the misoperation of a user is effectively avoided, and the use and operation experience is improved.

It should be noted that, in order to fully explain the inventive concept of the present invention, the functions (such as the key circuit, the trigger switch circuit, the comparison circuit and the delay circuit) to be executed by each circuit unit are generally described in the above embodiments by functional naming based on the operating principle of the shutdown circuit. It will be understood by those skilled in the art that, based on the functions to be implemented by the circuit units disclosed in the above embodiments, the specific implementations may be modified, replaced or changed according to the actual needs, and are not limited to the figures shown in the specification.

As shown in fig. 5a and 5b, in some embodiments, the delay circuit 113 may include a first capacitor C1. The first capacitor C1 is an electronic component capable of accommodating electric charges, and the voltage change at the input end of the trigger switch circuit is delayed by the charging/discharging function of the first capacitor C1. The RC delay circuit is formed by the first capacitor C1 and the first resistor R1, and the charging and discharging speed of the capacitor is limited by the shunting action of the second resistor and the third resistor, so that the delay time is adjusted.

In this embodiment, the voltage across the first capacitor C1 does not suddenly change, and when the trigger switch circuit 112 is turned on, the first capacitor C1 starts to discharge to gradually decrease the voltage. When the trigger switch circuit 112 is turned off, the first capacitor C1 is gradually charged to have a preset voltage, and referring to fig. 5a, a time-delay change of the voltage at the point P1 is realized, so that a time-delay shutdown is realized.

In other embodiments, when implemented by an inverter, a plurality of inverters may be connected in series between the controlled terminal of the trigger switch circuit 112 and the key circuit.

With continued reference to fig. 5a and 5b, in some embodiments, the trigger switch circuit 112 may include: a first resistor R1 and a switch tube Q1.

One end of the first resistor R1 is connected to the second power source VCC, and the other end of the first resistor R1 is connected to the input end of the switching tube Q1. The output end of the switching tube Q1 is grounded GND. The controlled end of the switching tube Q1 is connected to the key circuit 111, and can switch between a closed state and an open state according to a user trigger signal formed by the key circuit 111, and output a high-level or low-level signal to provide a required shutdown signal for the comparison circuit.

In the present embodiment, the "switching tube" refers to an electronic device used as a switch. The specific application can be selected according to the needs of the actual situation, and suitable devices including but not limited to MOS transistors, triodes, and other similar electronic devices can be used.

With continued reference to fig. 5a and 5b, in some embodiments, the comparison circuit 120 may include: a second resistor R2, a third resistor R3 and a comparator A.

One end of the second resistor R2 is connected to the second power VCC, the other end of the second resistor R2 is connected to one end of the third resistor R3, and the other end of the third resistor R3 is grounded. Thus, the second resistor R2 and the third resistor R3 connected in series form a voltage divider circuit, and a desired target voltage can be formed at the common terminal P1 of both. The common terminal P2 of the second resistor R2 and the third resistor R3 is connected to the first input terminal of the comparator a. A second input of comparator a is connected to a flip-flop circuit 110. The output end of the comparator A is connected with the controlled end of the first power supply.

In the present embodiment, the comparator a is a device for comparing voltages between two input terminals and outputting a corresponding level signal at an output terminal according to the voltage comparison result between the input terminals. It may also be referred to as a "voltage comparator". In this embodiment, for simplicity of presentation, the inverting input of the comparator is illustratively labeled as the first input, and the non-inverting input of the comparator is labeled as the second input.

In actual use, the trigger circuit 110 may cause the level of the comparator a between the first input terminal and the second input terminal to change (for example, the first input terminal is larger than the second input terminal, and the first input terminal is smaller than the second input terminal). Thus, in response to the level change, the level signal output from the output terminal of the comparator a is inverted (e.g., from a low level signal to a high level signal) and is provided to the power supply 30 as the power-off signal.

With continuing reference to fig. 5a and 5b, in an embodiment, the comparison circuit may further include a fourth resistor R4. One end of the fourth resistor R4 is connected to the second power source VCC, and the other end of the fourth resistor is connected to the output terminal of the comparator a.

The fourth resistor is used for pulling up the voltage at the output end of the comparator, so that the level of the output end of the comparator is prevented from fluctuating due to interference signals, and the fourth resistor is combined with a subsequent diode (refer to fig. 6), so that the diode is kept in an off state when not triggered, and the first power supply is prevented from being turned off mistakenly.

In order to fully describe the shutdown circuit provided in the embodiments of the present invention, the following describes the operation process of the shutdown circuit in detail with reference to the specific examples shown in fig. 5a and fig. 5 b.

The first input end of the comparator A is an inverting input end, and the second input end of the comparator A is a non-inverting input end. The output of comparator a is labeled OUT. The controlled terminal of the switching tube Q1 is labeled IN. The user trigger signal is a high level signal, and the power-off signal is a high level signal.

As shown in fig. 5a, when the user trigger signal is not received, the switching tube Q1 is in an open state. At this time, the voltage at the inverting input terminal of the comparator is the first voltage V1 of the first connection node P1, and the voltage at the non-inverting input terminal of the comparator is the second voltage V2 of the second connection node P2. In the case where V1 > V2, the output terminal OUT of the comparator continuously outputs a low level signal.

As shown in fig. 5b, when receiving a user trigger signal (i.e. a high level signal) formed by the key circuit, the switching tube Q1 is closed and conducted. Thereby, the first capacitor C1 starts to discharge, and the voltage of the first connection node P1 starts to gradually decrease.

When the voltage of the first connection node P1 decreases to be equal to or less than the second connection node voltage P2, the voltage signal at the output terminal OUT of the comparator is inverted from outputting a low level signal to outputting a high level signal (i.e., outputting a power-off signal).

Therefore, the shutdown circuit can correspondingly output the power-off signal according to whether the user trigger signal is received or not, so that the shooting equipment is controlled to be shut down.

The embodiment of the utility model provides a one of them favorable aspect of shutdown circuit is: the comparator is used as a main element, the detection function of the microcontroller is not required, the advantages of simplicity, stability and reliability are achieved, and the problem that the microcontroller cannot be shut down due to dead halt caused by detection is solved. Moreover, a certain response time can be provided by additionally arranging the first capacitor, and the situation of false triggering can be well avoided.

In other embodiments, with continued reference to fig. 3, the shutdown circuit may further include an isolation circuit 130 disposed at the rear end of the output of the comparison circuit. The input end of the isolation circuit 130 is connected to the output end of the comparison circuit 120, and the output end thereof is connected to the controlled end of the power supply, so as to isolate the shutdown circuit from the external power supply, which can be implemented by using an optical coupler or other isolation devices.

Alternatively, as shown in fig. 4, the shutdown circuit may further include a unidirectional turn-on circuit 140. The unidirectional one-way circuit 140 is a circuit having a low forward conduction resistance and a large reverse conduction resistance, and is, for example, a diode having unidirectional conduction characteristics.

The cathode of the unidirectional circuit 140 is connected to the output terminal of the comparator, and the anode of the unidirectional circuit 140 is connected to the controlled terminal of the first power supply, so as to prevent the external electrical signal from being reversely input into the shutdown circuit without affecting the output of the control signal from the output terminal of the comparator.

Fig. 6 is a schematic circuit diagram of a shutdown circuit according to an embodiment of the present invention, which exemplarily shows a shutdown circuit. The following describes in detail the operation principle of the shutdown circuit controlling the shooting device to shutdown with reference to fig. 6.

In this embodiment, the switching transistor Q1 is implemented by a MOS transistor. The grid electrode of the MOS tube is used as the controlled end of the switch tube Q1, and the source electrode and the drain electrode of the MOS tube are respectively used as the input end and the output end of the switch tube Q1. The unidirectional conducting circuit 140 is implemented by a diode D1. The delay circuit is realized by a first capacitor C1.

As shown in fig. 6, the drain of the switching tube Q1 is grounded, and the gate of the switching tube Q1 is connected to the key circuit for receiving a user trigger signal. The source electrode of the switching tube Q1 is connected with the inverting input end of the comparator A. One end of the first capacitor C1 is grounded, and the other end of the first capacitor C1 is connected to the source of the switching tube Q1.

One end of the first resistor R1 is connected to the second power source VCC, and the other end of the first resistor is connected to a first connection node P1 between the first capacitor C1 and the source electrode of the switching tube Q1.

One end of the second resistor R2 is connected to the second power VCC, and the other end of the second resistor R2 is grounded through the third resistor R3. A second connection node P2 between the second resistor R2 and the third resistor R3 is connected to the non-inverting input terminal of the comparator a.

The output end of the comparator A is connected with the anode of the diode D1, and the cathode of the diode D1 is connected with the controlled end of the first power supply so as to output a power-off signal. One end of the fourth resistor R4 is connected with the second power supply VCC, and the other end of the fourth resistor R4 is connected with the output end of the comparator A. The diode D1 and the MOS tube Q1 can play a good isolation role, so that the shutdown circuit can be isolated from other functional circuits, and mutual interference and influence are avoided. In some embodiments, with continued reference to fig. 6, the shutdown circuit further includes: a second capacitor C2. One end of the second capacitor C2 is connected to the second power VCC, and the other end of the second capacitor C2 is connected to the ground GND. The second capacitor C2 can provide a certain filtering function to keep the supply voltage stable.

In an actual use process, on one hand, when the controlled end of the trigger switch circuit does not receive a high-level user trigger signal, the MOS transistor Q1 does not reach the turn-on voltage and is in a cut-off state. At this time, the voltage at the first connection node P1 is a first voltage, which may charge the first capacitor C1. The voltage at the second connection node P2 is a second voltage smaller than the first voltage due to the voltage division of the second resistor R2 and the third resistor R3 connected in series.

Accordingly, the voltage of the inverting input terminal of the comparator connected to the first connection node P1 is greater than the voltage of the non-inverting input terminal of the comparator connected to the second connection node P2, and the output terminal of the comparator will output a low level signal.

On the other hand, when receiving a high level trigger signal, the MOS transistor Q1 reaches a turn-on voltage and is in a conducting state. At this time, the first connection node P1 is connected to the ground GND. The first capacitor C1 starts to discharge, so that the voltage at the first connection node P1 is slowly decreased and is not rapidly pulled down. The voltage at the second connection node P2 remains unchanged.

Accordingly, the voltage of the inverting input terminal of the comparator connected to the first connection node P1 is decreased. When the voltage of the inverting input end of the comparator is reduced to be less than or equal to the second voltage, the output end of the comparator can output a high level which is used as a power-off signal and is output to the controlled end of the first power supply through the port OUT, and therefore the shooting equipment is turned off.

As described above, the voltage at the inverting input terminal of the comparator is not pulled down instantaneously with the conduction of the MOS transistor. Therefore, a period of time elapses from when the shutdown circuit receives the trigger signal to when the power-off signal is output to shut down the photographing apparatus. In the present embodiment, the term "response time" may be used to denote the elapsed time.

In some embodiments, the response time may be determined by a first capacitance value of the first capacitor C1, a first resistance value of the first resistor R1, a second resistance value of the second resistor R2, and a third resistance value of the third resistor R3. Therefore, technicians can obtain ideal response time meeting actual use requirements by adjusting the first capacitance value, the first resistance value, the second resistance value and the third resistance value according to the requirements of actual conditions.

Fig. 7 is a table exemplarily showing response times of the shutdown circuit shown in fig. 6 for different combinations of the first capacitance value, the first resistance value, the second resistance value, and the third resistance value.

The utility model discloses one of them beneficial aspect of shutdown circuit is: under the condition of not depending on software control, the adjustment of the response time can be conveniently realized by changing the capacitance value and the resistance value so as to adapt to the requirements of different application scenes. For example, the appropriate response time can ensure that a brief or momentary touch or press action does not result in the shutdown circuit sending a control signal, thereby effectively avoiding the misoperation of a user and improving the use and operation experience.

The foregoing is a further detailed description of the invention in connection with specific/preferred embodiments and it is not intended that the invention be limited to these specific embodiments. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims

1. A shutdown circuit, comprising:

2. The shutdown circuit of claim 1, wherein the trigger circuit comprises:

the controlled end of the trigger switch circuit is connected with the key circuit, the input end of the trigger switch circuit is connected with a preset level, the output end of the trigger switch circuit is connected with the input end of the comparison circuit, and the trigger switch circuit is used for being switched on when receiving the first control signal.

3. The shutdown circuit of claim 2, wherein the trigger circuit further comprises:

4. The shutdown circuit of claim 3, wherein the delay circuit comprises a first capacitor, one end of the first capacitor is connected to the output terminal of the trigger switch circuit, and the other end of the first capacitor is grounded.

5. The shutdown circuit of claim 2, wherein the trigger switch circuit comprises: a first resistor and a switching tube;

6. The shutdown circuit of claim 1, wherein the comparison circuit comprises: a second resistor, a third resistor and a comparator;

7. The shutdown circuit of claim 6, wherein the comparison circuit further comprises:

8. The shutdown circuit of claim 1, wherein the shutdown circuit further comprises:

9. A photographing apparatus characterized by comprising: a first power supply and a shutdown circuit as claimed in any one of claims 1 to 8; the shutdown circuit is connected with the controlled end of the first power supply.

10. The photographing apparatus of claim 9, wherein the first power supply comprises:

the battery is used for providing a power supply; and

the input end of the power management chip is connected with the battery, the output end of the battery management chip is used for outputting the power supply, the controlled end of the power management chip is connected with the shutdown circuit, and the power management chip is used for stopping outputting the power supply when receiving the power-off signal; and/or

The power supply comprises a power supply switch circuit, wherein the input end of the power supply switch circuit is connected with the battery, the output end of the power supply switch circuit is used for outputting the power supply, the controlled end of the power supply switch circuit is connected with the shutdown circuit, and the power supply switch circuit is used for being disconnected when receiving the power-off signal.