On-off circuit and electronic equipment

Abstract

The utility model relates to a startup and shutdown circuit and electronic equipment. The on-off circuit comprises a switching circuit which is provided with an input end, an output end and a control end, the input end is connected with a power supply input end, the output end is connected with a power supply output end, and the switching circuit is used for controlling the power supply input end to supply power to the power supply output end; the control circuit is electrically connected with the power supply input end and the control end respectively; the feedback circuit is electrically connected with the power supply output end and the control circuit, when the power supply output end supplies power to the feedback circuit, the feedback circuit can feed back electric signals to the control circuit, and the control circuit controls the switching circuit to be switched on after receiving the fed-back electric signals; the key circuit comprises a key switch, and the key circuit is electrically connected with the control circuit; when the key switch is closed, the control circuit controls the switch circuit to be switched on. The on-off circuit is provided with the switching circuit, the control circuit and the feedback circuit, so that the on-off circuit can form self-locking on-off only by lightly touching the key switch, frequent on-off is avoided, and the use is convenient.

Description

Technical Field

[0001] This application belongs to the technical field of electrical appliance startup and power-on, and particularly relates to a power-on and power-off circuit and an electronic device. Background Art

[0002] At present, with the continuous development of electronic technology, more and more small intelligent electronic products enter the market. These small intelligent electronic products basically adopt an internal battery structure. To consider energy conservation, small intelligent electronic products are all equipped with a power-on and power-off button, so that the intelligent electronic products can be in a shutdown state when leaving the factory. During use, it often happens that the power-on and power-off button is accidentally touched, resulting in the sudden shutdown of the small intelligent electronic product that is in use. To solve this problem, some manufacturers have designed intelligent electronic products with power-on startup, that is, during use, they are used in combination with a power adapter. The charging head of the power adapter is inserted into the power supply terminal of the small electronic product. And during use, it is necessary to keep connected to the power adapter, which brings inconvenience to use. At the same time, since the power-off method is to directly pull out the connector, it causes damage to the running system and hardware. To avoid sudden shutdown and damage to the running hardware, many small intelligent electronic products are provided with a delayed power-off circuit, resulting in increased costs and circuit complexity.

[0003] To solve the above problems, currently, more often a power-on and power-off button with a tactile switch is adopted, and the CPU main control participates in the control of power-on and power-off. This design makes the design of the power-on and power-off circuit complex and the cost high. Summary of the Utility Model

[0004] The purpose of this application is to provide a power-on and power-off circuit, aiming to solve the problems of inconvenient use and high cost existing in the power-on and power-off design of traditional small intelligent electronic products.

[0005] The first aspect of the embodiment of this application provides a power-on and power-off circuit, which includes:

[0006] A switch circuit, which has an input terminal, an output terminal and a control terminal. The input terminal is connected to a power supply input terminal, the output terminal is connected to a power supply output terminal, and the switch circuit is used to control the power supply input terminal to supply power to the power supply output terminal;

[0007] A control circuit, which is electrically connected to the power supply input terminal and the control terminal respectively, and is used to control the on and off of the switch circuit;

[0008] A feedback circuit, which is electrically connected to the power supply output terminal and the control circuit. When the power supply output terminal supplies power to the feedback circuit, the feedback circuit can feed back an electrical signal to the control circuit. When the control circuit receives the fed-back electrical signal, the control circuit controls the switch circuit to conduct;

[0009] The key circuit includes a key switch, and the key circuit is electrically connected to the control circuit; when the key switch is closed, the control circuit controls the switch circuit to conduct.

[0010] Further, the power-on and -off circuit further includes a low-battery shutdown control circuit electrically connected to the power supply. The low-battery shutdown control circuit is electrically connected to the control circuit or the feedback circuit. When the voltage of the power supply is lower than a predetermined threshold, the low-battery shutdown control circuit sends a low-battery current signal to the control circuit or the feedback circuit, and the control circuit controls the switch circuit to disconnect.

[0011] Further, the power-on and -off circuit further includes a shutdown control circuit. The shutdown control circuit includes a control unit, and the control unit is electrically connected to the control circuit and / or the feedback circuit.

[0012] Further, the switch circuit includes a main electronic switch tube. The input end of the main electronic switch tube is connected to the power supply input end, and the output end of the main electronic switch tube is connected to the power supply output end.

[0013] More preferably, the main electronic switch tube includes a triode, a MOS tube, a thyristor, etc.

[0014] Preferably, the power supply input end and the power supply output end are respectively grounded through a capacitor C1 and a capacitor C2.

[0015] Further, the control circuit includes a voltage-dividing circuit. The input end of the voltage-dividing circuit is connected to the power supply input end. An intermediate voltage end of the voltage-dividing circuit provides a control voltage to the control end of the main electronic switch tube, and the output end of the voltage-dividing circuit is grounded through the key switch.

[0016] Further, the voltage-dividing circuit includes a first resistor, a first capacitor, a second resistor, and a first diode connected in sequence. The first end of the first resistor is connected to the power supply input end, and the second end of the first resistor is connected to the control end of the main electronic switch tube. The negative electrode of the first diode is connected to the key switch.

[0017] Further, the control circuit further includes a switch branch circuit. One end of the switch branch circuit is connected to the control end of the main electronic switch tube, and the other end of the switch circuit is grounded. The switch circuit is connected in series with a secondary electronic switch tube, and the control end of the secondary electronic switch tube is electrically connected to the feedback circuit.

[0018] Further, the feedback circuit includes a feedback voltage-dividing circuit connected between the internal power supply VCC and the ground. An intermediate voltage end of the feedback voltage-dividing circuit provides a control voltage to the control end of the secondary electronic switch tube.

[0019] Further, the low - power shutdown control circuit includes a first voltage - dividing circuit connected to the power supply, a second voltage - dividing circuit connected to the internal power supply VCC, and a comparator U3. The first voltage - dividing circuit leads out a first intermediate potential terminal and connects it to the non - inverting input terminal of the comparator. The second voltage - dividing circuit leads out a second intermediate potential terminal and connects it to the inverting input terminal of the comparator. The output terminal of the comparator U3 is connected to the feedback circuit or the control circuit.

[0020] Further, the auxiliary electronic switch tube includes a triode, a MOS tube or a thyristor.

[0021] In the second aspect of the embodiments of the present application, an electronic device is provided, and the electronic device has the above - mentioned power - on and off circuit.

[0022] The beneficial effects of the embodiments of the present utility model compared with the prior art are as follows: By setting the switch circuit, the control circuit and the feedback circuit, the power - on and off circuit only needs to touch the key switch. The control circuit controls the switch circuit to conduct, the feedback circuit feeds back the current signal to the control circuit, and when the control circuit receives the feedback current signal and continuously controls the switch circuit to conduct, a self - locking power - on is formed, avoiding frequent power - on and off. The overall circuit is simple and easy to use. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the first power - on and off circuit provided by the embodiments of the present application;

[0024] Figure 2 It is a schematic structural diagram of the second power - on and off circuit provided by the embodiments of the present application;

[0025] Figure 3 It is a schematic structural diagram of the third power - on and off circuit provided by the embodiments of the present application;

[0026] Figure 4 It is a schematic structural diagram of the fourth power - on and off circuit provided by the embodiments of the present application;

[0027] Figure 5 It is a schematic structural diagram of the fifth power - on and off circuit provided by the embodiments of the present application;

[0028] Figure 6 It is a circuit schematic diagram of the power - on and off circuit of the present application;

[0029] Figure 7 It is another circuit schematic diagram of the power - on and off circuit of the present application;

[0030] Figure 8 It is a circuit schematic diagram of the low - power control circuit of the present application;

[0031] Figure 9 It is a circuit schematic diagram of the shutdown control circuit of the present application;

[0032] Reference numerals:

[0033] 1 - Power supply input terminal; 2 - Switching circuit; 3 - Power supply output terminal; 4 - Control circuit; 5 - Feedback circuit; 6 - Button circuit; 7 - Low battery shutdown control circuit; 8 - Shutdown control circuit; 9 - DC / DC circuit. Detailed implementation manners

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clear and understandable, the following further details this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0036] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to this application.

[0037] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality of" means two or more unless otherwise specifically defined.

[0038] Figure 1 The structural schematic diagram of the power-on and power-off circuit provided by a preferred embodiment of this application is shown. For the convenience of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0039] The power-on and power-off circuit includes: a switching circuit 2, a control circuit 4, a feedback circuit 5, and a button circuit 6. Among them, the switching circuit 2 is provided with an input terminal, an output terminal, and a control terminal. The input terminal is connected to a power supply input terminal 1. See the attached Figures 1 to 7; The output terminal is connected to the power supply output terminal 3 and is used for the power supply input terminal 1 to supply power to the power supply output terminal 3; The control circuit 4 is respectively electrically connected to the power supply input terminal 1 and the control terminal of the switch circuit 2 and is used to control the on / off of the switch circuit 2; The feedback circuit 5 is electrically connected to the control circuit 4, see Figure 1 、 Figure 2 and Figure 9 ; When the power supply output terminal supplies power to the feedback circuit, that is, when the power supply output terminal 3 outputs current, the feedback circuit 5 can feed back an electrical signal to the control circuit 4, and the control circuit 4 receives the fed-back electrical signal and controls the switch circuit 2 to conduct; The key circuit 6 includes a key switch, and the key circuit 6 is electrically connected to the control circuit 4; When the key switch is closed, the control circuit 4 controls the switch circuit 2 to conduct.

[0040] In the embodiment of the present application, the power supply to the electronic product is controlled by setting the switch circuit 2. The power supply input terminal 1 is the terminal for the power-on and -off circuit to receive the power supply signal from the power supply. The power supply can be the built-in lithium battery of the electronic product, or an external dry battery or a power adapter, etc. The structural part of the key switch of the key circuit 6 is arranged on the housing of the electronic product. During use, first press the key switch to make the key switch closed and conductive. At this time, the control circuit 4 sends a control signal to the control terminal of the switch circuit 2, and the switch circuit 2 conducts, and the input terminal and the output terminal conduct; The power supply provides power to the power supply output terminal 3 through the switch circuit 2. The power supply output terminal 3 serves as the power supply input terminal of the entire electronic product and supplies power to the entire electronic product for the electronic product to start working; At this time, the power supply output terminal 3 can directly supply power to the feedback circuit 5, or can first perform step-up and step-down processing through the DC / DC circuit 9 and then supply power to the feedback circuit 5. In the case of no other signal input, the feedback circuit 5 feeds back an electrical signal to the control circuit 4, and the control circuit 4 receives the fed-back electrical signal and controls the switch circuit 2 to continuously conduct. Even at this time, when the key switch of the key circuit 6 is released and the key switch is disconnected, since the feedback circuit 5 continuously feeds back an electrical signal to the control circuit 4, the control circuit 4 always controls the switch circuit 2 to conduct, and the power supply continuously supplies power to the electronic product, thus forming a self-locking power supply. This power supply method is relatively simple as a whole; There is no need to worry about accidentally triggering the switch button and the sudden power-off caused by directly pulling out the power supply input terminal 1, which may damage the hardware; And the problem of complex circuit caused by controlling the power-on and -off through the MCU. It is convenient to use.

[0041] See Figures 3 to 7 ; The power-on and -off circuit further includes a low-battery shutdown control circuit 7 electrically connected to the power supply. The low-battery shutdown control circuit 7 is electrically connected to the control circuit 4 or the feedback circuit 5. When the voltage of the power supply is lower than a predetermined threshold, the low-battery shutdown control circuit 7 sends a low-battery current signal to the control circuit 4 or the feedback circuit 5, and the control circuit 4 controls the switch circuit 2 to disconnect.

[0042] During the use of electronic products, the state of running with low battery power often occurs. This state causes relatively large damage to the battery serving as the power source. To avoid the battery from running in a low-battery state, the embodiment of this application designs a low-battery shutdown control circuit 7. The low-battery control circuit 4 can be a circuit with an MCU for battery power detection. The battery power has a certain proportional relationship with the external power supply voltage of the battery. When the battery power is low, the external power supply voltage drops significantly, such as from the normal power supply of 5V to 4.5V, etc.; by testing the external power supply voltage, the battery power can be obtained. The predetermined threshold can be 90%, 80%, 75%, 70%, or 60% of the normal battery voltage, etc. Generally speaking, the larger the total battery power, the smaller the predetermined threshold can be. By detecting the voltage, the battery power information is obtained. When the voltage of the battery is lower than the threshold, the low-battery shutdown control circuit 7 can directly feedback to the control circuit 4, or can feedback to the control circuit 4 through the feedback circuit 5. The control circuit 4 then controls the switch circuit 2 to disconnect and stop power supply.

[0043] See Figure 4 、 Figure 5 、 Figure 6 and Figure 9 ; The power-on and -off circuit further includes a shutdown control circuit 8. The shutdown control circuit 8 includes a control unit, and the control unit is electrically connected to the control circuit 4 or / and the feedback circuit 5.

[0044] The control unit can be a control chip of the electronic product, such as a central processing unit (Central Processing Unit) CPU, integrated circuit (IC), single-chip microcomputer, etc.; it can also be a logic circuit, etc.; when in use, a shutdown signal is sent to the control circuit 4 through the control unit, and the control circuit 4 controls the switch circuit 2 to disconnect; a shutdown signal can also be sent to the feedback circuit 5, and the feedback circuit 5 stops feeding back electrical signals to the control circuit 4, and the control circuit 4 controls the switch circuit 2 to disconnect.

[0045] When controlling the control unit to issue a shutdown signal, in this embodiment, an exemplary long-press method is adopted. For example, when using a touch screen, press and hold on the shutdown button for a period of time. If it is a button type, long-press on the shutdown button for a period of time; this period of time can be set, such as 3s, 5s, 7s, etc.; to avoid accidental triggering.

[0046] See Figures 7 to 8; The switch circuit 2 includes a main electronic switch tube. The input end of the main electronic switch tube is connected to the power supply input end 1, and the output end of the main electronic switch tube is connected to the power supply output end 3. Preferably, the main electronic switch tube includes a triode, a MOS tube, a thyristor, etc. In this embodiment, the main electronic switch tube is a MOS tube. The source of the MOS tube is the input end, the drain of the MOS tube is the output end, the gate of the MOS tube is the control end. The source of the MOS tube is connected to the power supply input end 1 (POWER_IN), and the drain of the MOS tube is connected to the power supply output end 3 (POWER_OUT); the gate of the MOS tube is connected to the control circuit 4. By controlling the potential of the gate through the control circuit 4, the conduction of the MOS tube is further controlled. As an equivalent deformation, the MOS tube can be replaced by a triode, etc. In addition to the electronic switch tube, the switch circuit 2 can also be a switch control circuit 4, and the conduction and interruption of the switch control circuit 4 are controlled through the control end.

[0047] See Figure 5 、 Figure 6 , the power supply input end 1 and the power supply output end 3 are respectively grounded through the capacitor C1 and the capacitor C2. Both the capacitor C1 and the capacitor C2 are used for filtering to maintain the voltage stability of the power supply input end 1 and the control end and remove background clutter.

[0048] See Figure 5 、 Figure 6 , the control circuit 4 includes a voltage dividing circuit. The input end of the voltage dividing circuit is connected to the power supply input end 1. An intermediate voltage end of the voltage dividing circuit provides a control voltage to the control end of the main electronic switch tube, that is, is connected to the gate of the MOS tube. The output end of the voltage dividing circuit is grounded through the key switch.

[0049] To simplify the key circuit 6, only the key switch is set in the embodiment of the present application. Of course, for safety, the key switch can be connected in series with a protection diode, etc. By setting the voltage dividing circuit in the control circuit 4, when the key switch K1 is pressed, the power supply input end 1 is grounded through the voltage dividing circuit to form a loop. The intermediate voltage end of the voltage dividing circuit can provide a potential lower than the power supply input end 1 to the gate of the MOS tube, and the source of the MOS tube is connected to the power supply input end 1. Thus, the potential of the source of the MOS tube is higher than the potential of the gate of the MOS tube. The MOS tube is of P type and the MOS tube conducts. Thus, the conduction of the switch circuit 2 is controlled by the key switch.

[0050] Among them, the voltage dividing circuit includes a first resistor connected to the power supply input end 1. The first resistor is sequentially connected in series with a first capacitor, a second resistor, and a first diode; the first end of the first resistor is connected to the power supply input end, and the second end of the first resistor is connected to the control end of the main electronic switch tube; the negative electrode of the first diode is connected to the key switch. See Figure 6 、 Figure 7, specifically: the resistor R1 is the first resistor, the capacitor C1 is the first capacitor, the resistor R7 is the second resistor, the input end of the resistor R1 is connected to the power supply input terminal 1, and the output end of the resistor R1 is connected to the control end of the main electronic switch tube, that is, connected to the gate of the MOS tube; the output end of the resistor R7 is connected to the key switch of the key circuit 6. In the example of this embodiment, a diode D2 is connected between the resistor R7 and the key switch. The setting of these electronic components can play roles such as preventing reverse connection and filtering. The output end of the resistor R1 is the intermediate voltage terminal. Of course, several more resistors can be connected in series, and the output end of other resistors can be used as the intermediate voltage terminal.

[0051] See Figure 5 , Figure 6 , the control circuit 4 further includes a switch branch circuit. One end of the switch branch circuit is connected to the control end of the main electronic switch tube, that is, connected to the gate of the MOS tube, and the other end of the switch branch circuit is grounded. A secondary electronic switch tube is connected in series in the switch circuit, and the control end of the secondary electronic switch tube is electrically connected to the feedback circuit 5.

[0052] Since the two ends of the resistor R1 are respectively connected to the power supply input terminal 1 and the gate of the MOS tube, the power supply input terminal 1 is grounded through the resistor R1 and the switch circuit. The resistor R1 is connected in series with the switch circuit. When the power supply output terminal 3 supplies power to the electronic product, the feedback circuit 5 sends a feedback current signal to the secondary electronic switch tube, and the secondary electronic switch tube conducts. The power supply input terminal 1, the resistor R1, the switch circuit, and the ground form a loop. The gate potential and source potential of the MOS tube are respectively the potentials at both ends of the resistor R1, and the gate potential is lower than the source potential, so the MOS tube conducts, thus forming a self-locking circuit.

[0053] See Figure 7 , Figure 6 , the feedback circuit 5 includes a feedback voltage dividing circuit connected between the internal power supply VCC and the ground. An intermediate voltage terminal of the feedback voltage dividing circuit provides a control voltage to the control end of the secondary electronic switch tube; specifically, the feedback voltage dividing circuit is: a resistor R10 connected to the internal power supply VCC, the output end of the resistor R10 is grounded through a resistor R13, and the output end of the resistor R10 is connected to the control end of the secondary electronic switch tube through a resistor R11. See Figure 9 , the internal power supply VCC is obtained by stepping up or down the voltage of the power supply input terminal 1 through the DC / DC circuit 9.

[0054] When the key switch is pressed, the power supply input terminal 1 is conducted to the power supply output terminal 3, and the power supply supplies power to the electronic product. The internal power supply VCC has a certain potential, such as 5V, 12V, etc.; the resistor R10 and the resistor R13 form a voltage dividing circuit. The potential at the input end of the resistor R13 is the same as the potential at the control end of the secondary electronic switch tube, and the potential at the control end of the secondary electronic switch tube rises, so the secondary electronic switch tube conducts. The secondary electronic switch tube can be a triode, a MOS tube, a thyristor, etc.

[0055] Secondly, in specific settings, the feedback circuit 5 further includes a capacitor C5 and a capacitor C6; the capacitor C5 is connected in parallel with the resistor R13, one end of the capacitor C6 is connected to the output end of the resistor R10, and the other end of the capacitor C6 is grounded. The above is only an exemplary description. Secondly, a diode D3 may be provided between the resistor R10 and the resistor R13 to prevent the internal power supply from being reversely connected.

[0056] See Figure 8 , the low-battery shutdown control circuit 7 includes a first voltage-dividing circuit connected to the power supply, a second voltage-dividing circuit connected to the internal power supply VCC, and a comparator U3; the first voltage-dividing circuit leads out a first intermediate potential terminal and is connected to the non-inverting input terminal of the comparator, the second voltage-dividing circuit leads out a second intermediate potential terminal and is connected to the inverting input terminal of the comparator, and the output terminal of the comparator U3 is connected to the feedback circuit 5 or to the control terminal of the sub-electronic switch tube of the switch circuit.

[0057] To obtain the output voltage of the battery as the power supply, the embodiment of the present application adopts a first voltage-dividing circuit. In this embodiment, the first voltage-dividing circuit includes a series-connected resistor R18 and a resistor R19. One end of the resistor R18 is connected to the output end of the battery, and the output end of the resistor R18 is connected to the non-inverting input terminal of the comparator U3; the second voltage-dividing circuit provides a reference voltage for comparing with the voltage component of the battery. When the battery power is lower than a certain value, the voltage component of the battery will be lower than the threshold, that is, the reference voltage, and the comparator outputs a negative level. When the output terminal of the comparator U3 is directly connected to the sub-electronic switch tube, the potential of the control terminal of the sub-electronic switch tube is directly pulled down, and the sub-electronic switch tube is turned off; when the output terminal of the comparator U3 is connected to the feedback circuit 5, as shown in the figure, the output terminal of the comparator U3 is connected to the output end of the resistor R10, pulling down the potential of the input end of the resistor R12, and further pulling down the potential of the sub-electronic switch tube, resulting in the cutoff of the sub-resistor switch tube.

[0058] Among them, the sub-electronic switch tube includes a triode, a MOS tube or a thyristor. In this embodiment, the sub-electronic switch tube adopts a triode Q3. The base of the triode Q3 is connected to the output end of the resistor R11, the collector of the triode Q3 is connected to the output end of the resistor R5, and the emitter of the triode Q3 is grounded.

[0059] An electronic device having the above-mentioned power-on and power-off circuit.

[0060] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A power on / off circuit, characterized in that: include: A switch circuit is provided with an input end, an output end and a control end, the input end is connected to the power supply input end, the output end is connected to the power supply output end, and the switch circuit is used to control the power supply input end to supply power to the power supply output end; A control circuit, electrically connected to the power supply input terminal and the control terminal respectively, and used to control the on and off of the switch circuit; A feedback circuit is electrically connected to the power supply output terminal and the control circuit. When the power supply output terminal supplies power to the feedback circuit, the feedback circuit can feed back an electrical signal to the control circuit. The control circuit receives the feedback electrical signal and controls the switch circuit to conduct. The key circuit includes a key switch, and the key circuit is electrically connected to the control circuit; when the key switch is closed, the control circuit controls the switch circuit to be turned on.

2. The switch circuit according to claim 1, characterized in that: The switch circuit also includes a low-battery shutdown control circuit electrically connected to the power supply, and the low-battery shutdown control circuit is electrically connected to the control circuit or the feedback circuit. When the voltage of the power supply is lower than a predetermined threshold, the low-battery shutdown control circuit sends a low-battery current signal to the control circuit or the feedback circuit, and the control circuit controls the switch circuit to disconnect.

3. The switch circuit according to claim 1 or 2, characterized in that: The power on / off circuit further includes a shutdown control circuit, and the shutdown control circuit includes a control unit, and the control unit is electrically connected to the control circuit and / or the feedback circuit.

4. The switch circuit according to claim 3, characterized in that: The switch circuit comprises a main electronic switch tube, an input end of the main electronic switch tube is connected to the power supply input end, and an output end of the main electronic switch tube is connected to the power supply output end.

5. The switch circuit according to claim 4, characterized in that: The control circuit includes a voltage divider circuit, an input end of the voltage divider circuit is connected to a power supply input end, an intermediate voltage end of the voltage divider circuit provides a control voltage to a control end of the main electronic switch tube, and an output end of the voltage divider circuit is grounded via a key switch.

6. The switch circuit according to claim 5, characterized in that: The voltage divider circuit includes a first resistor, a first capacitor, a second resistor and a first diode connected in sequence; the first end of the first resistor is connected to the power supply input end, and the second end of the first resistor is connected to the control end of the main electronic switch tube; the cathode of the first diode is connected to the key switch.

7. The switch circuit according to claim 5 or 6, characterized in that: The control circuit also includes a switch branch circuit, one end of which is connected to the control end of the main electronic switch tube, and the other end of which is grounded. The switch circuit is connected in series with a secondary electronic switch tube, and the control end of the secondary electronic switch tube is electrically connected to the feedback circuit.

8. The switch circuit according to claim 7, characterized in that: The feedback circuit includes a feedback voltage divider circuit connected between an internal power supply VCC and ground, and an intermediate voltage terminal of the feedback voltage divider circuit provides a control voltage to a control terminal of the auxiliary electronic switch tube.

9. The power on / off circuit according to claim 2, characterized in that: The low-battery shutdown control circuit includes a first voltage-dividing circuit connected to a power supply, a second voltage-dividing circuit connected to an internal power supply VCC, and a comparator U3; the first voltage-dividing circuit leads out a first intermediate potential terminal and is connected to the non-inverting input terminal of the comparator, the second voltage-dividing circuit leads out a second intermediate potential terminal and is connected to the inverting input terminal of the comparator, and the output terminal of the comparator U3 is connected to a feedback circuit or a control circuit.

10. An electronic device, characterized in that: The electronic device comprises the switch circuit according to any one of claims 1 to 9.

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