Power supply control circuit and power supply control device

Abstract

The invention provides a power supply control circuit and a power supply control device, the power supply control circuit can be applied between an external load and an external power supply to carry out timely and effective overcurrent protection on the external power supply, and the power supply control circuit comprises a first switch module, a second switch module, a current limiting resistor and a discharge resistor; the first end of the current-limiting resistor is connected with the external power supply, and the second end of the current-limiting resistor is connected with the first switch module; at least one end of the discharge resistor is connected with the first switch module; the first switch module is also connected with the external load, and a first loop is formed in a first state of the first switch module; in the second state of the first switch module, a second loop is formed; the first end of the second switch module is connected with the first end of the current-limiting resistor, the second end of the second switch module is connected with the external load, and when the second switch module is in a conducting state, the current-limiting resistor is short-circuited.

Description

Technical Field

[0001] The present application relates to the technical field of current surge protection, and in particular to a power supply control circuit and a power supply control device. Background Art

[0002] In modern society, there are more and more electrical devices of various types. Most of the electrical devices will have a large inrush current when connected to the power supply. If the inrush current is too large, the power supply will trigger the overcurrent protection, and the electrical device will not work properly. In the prior art, in order to avoid power supply protection, a power supply with higher power is generally selected to power the electrical device, but this will significantly increase the cost. Summary of the invention

[0003] One advantage of the present application is that it provides a power supply control circuit and a power supply control device, which can be applied between an external load and an external power supply to provide timely and effective overcurrent protection for the external power supply.

[0004] Another advantage of the present application is to provide a power supply control circuit and a power supply control device, wherein in order to achieve the above advantages, no expensive materials or complex structures are required in the present application. Therefore, the solution provided by the present application can successfully and effectively solve the above problems, and not only provides a simple power supply control circuit and a power supply control device, but also increases the practicality and reliability of the power supply control circuit and the power supply control device.

[0005] Based on this, in order to achieve at least one of the above advantages or other advantages and purposes of the present application, the present application provides a power supply control circuit, which is applied between an external power supply and an external load, and includes a first switch module, a second switch module, a current limiting resistor and a discharge resistor;

[0006] The first end of the current limiting resistor is connected to the external power supply, and the second end of the current limiting resistor is connected to the first switch module;

[0007] At least one end of the discharge resistor is connected to the first switch module;

[0008] The first switch module is also connected to the external load. In a first state of the first switch module, the external load and the discharge resistor form a first loop; in a second state of the first switch module, the external power supply, the current limiting resistor and the external load form a second loop;

[0009] The first end of the second switch module is connected to the first end of the current limiting resistor, and the second end of the second switch module is connected to the external load. When the second switch module is in an on state, the current limiting resistor is short-circuited.

[0010] According to an embodiment of the present application, the first switch module and the second switch module respectively include one relay or multiple relays, or include a MOS tube switch circuit.

[0011] According to one embodiment of the present application, the first switch module includes a relay, the relay includes at least two static contacts, one static contact of the relay is connected to the second end of the current limiting resistor, at least one static contact of the relay is connected to at least one end of the discharge resistor, and the moving contact of the relay is connected to the external load. When the relay is in a first state, the external load is connected to the discharge resistor; when the relay is in a second state, the current limiting resistor is connected between the external power supply and the external load.

[0012] According to one embodiment of the present application, the relay is a first relay, the first relay has two moving contacts and four static contacts, the first end of the current limiting resistor is connected to the positive end of the external power supply, the first static contact of the first relay is connected to the second end of the current limiting resistor, the second static contact of the first relay is connected to the first end of the discharge resistor, the third static contact of the first relay is connected to the negative end of the external power supply, and the fourth static contact of the first relay is connected to the second end of the discharge resistor;

[0013] The first moving contact of the first relay is connected to the positive end of the external load, and the second moving contact of the first relay is connected to the negative end of the external load. When in a first state, the first moving contact of the first relay is connected to the second static contact of the first relay, and the second moving contact of the first relay is connected to the fourth static contact of the first relay, so that the external load and the discharge resistor form a first loop; when in a second state, the first moving contact of the first relay is connected to the first static contact of the first relay, and the second moving contact of the first relay is connected to the third static contact of the first relay, so that the external power supply, the current limiting resistor and the external load form a second loop.

[0014] According to one embodiment of the present application, the relay is a second relay, the second relay has a moving contact and two static contacts, the first end of the current limiting resistor is connected to the positive end of the external power supply, the first static contact of the second relay is connected to the second end of the current limiting resistor, the second static contact of the second relay is connected to the first end of the discharge resistor, and the second end of the discharge resistor is connected to the negative end of the external load and the negative end of the external power supply;

[0015] The moving contact of the second relay is connected to the positive end of the external load. When in a first state, the moving contact of the second relay is connected to the second static contact of the second relay, so that the external load and the discharge resistor form a first loop; when in a second state, the moving contact of the second relay is connected to the first static contact of the second relay, so that the external power supply, the current limiting resistor and the external load form a second loop.

[0016] According to one embodiment of the present application, the first switch module includes a third relay and a fourth relay, the second end of the third relay and the second end of the fourth relay are both connected to the external load, and when the third relay and the fourth relay are in a first state, the external load is connected to the discharge resistor; when the third relay and the fourth relay are in a second state, the current limiting resistor is connected between the external power supply and the external load.

[0017] According to one embodiment of the present application, the power supply control circuit also includes a first control unit and a second control unit, the first control unit is connected to the first switch module, and is used to control the first switch module to switch between the first state and the second state based on a first control signal and a second control signal; the second control unit is connected to the second switch module, and is used to control the second switch module to be turned on based on a third control signal, and to control the second switch module to be turned off based on a fourth control signal.

[0018] According to one embodiment of the present application, the second control unit includes an AND gate and a comparator, the first input end of the AND gate is connected to the output end of the comparator, and the second input end of the AND gate receives the third control signal or the fourth control signal of the second switch module; the high potential end of the comparator receives the load voltage signal of the external load, and the low potential end of the comparator receives a preset reference voltage signal.

[0019] According to another aspect of the present application, the present application further provides a power supply control device, which is applied between an external power supply and an external load. The power supply control device includes: the above-mentioned power supply control circuit, and a controller electrically connected to the power supply control circuit, and the controller is used to generate corresponding control signals to control the state switching of the first switch module and the second switch module.

[0020] According to an embodiment of the present application, the initial state of the second switch module is the disconnected state, and the initial state of the first switch module is the first state; the controller is used to generate a corresponding control signal to control the state switching of the first switch module and the second switch module, specifically:

[0021] The controller is used to generate a first control signal to control the state of the first switch module to switch to a second state when the external load needs to be connected to the external power supply, so that the external power supply, the current limiting resistor and the external load form a second loop, and, after the connection time between the external load and the external power supply reaches a preset delay time, generate a third control signal to control the state of the second switch module to switch to an on state to short-circuit the current limiting resistor; and,

[0022] The controller is also used to generate a fourth control signal to control the state of the second switch module to switch to a disconnected state when the external load needs to disconnect from the external power supply, and to generate a second control signal to control the state of the first switch module to switch to a first state, so that the external load and the discharge resistor form a first loop.

[0023] The power supply control circuit provided in the present application can, with the help of the first circuit formed by the first switch module in the first state and the second circuit formed by the first switch module in the second state, realize overcurrent protection by connecting a current limiting resistor between the external power supply and the external load when the external load is using power, and when the external load is powered off, connect a discharge resistor at both ends of the external load to quickly discharge the residual power of the external load; and by controlling whether the second switch module is turned on, thereby controlling whether to short-circuit the current limiting resistor, it is achieved that the current limiting resistor is not short-circuited during overcurrent protection, and the current limiting resistor is short-circuited after the overcurrent protection is completed, thereby reducing energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A circuit module diagram of a power supply control circuit provided for one embodiment of the present application;

[0026] Figure 2 A circuit diagram of a power supply control circuit provided in another embodiment of the present application;

[0027] Figure 3 A circuit diagram of a power supply control circuit provided for another embodiment of the present application;

[0028] Figure 4 A circuit diagram of a power supply control circuit provided for another embodiment of the present application;

[0029] Figure 5 A circuit diagram of a power supply control circuit provided for other embodiments of the present application;

[0030] Figure 6 A circuit schematic diagram of a second control unit in the power supply control circuit according to the above embodiment of the present application is shown.

[0031] Figure numerals: 10, power supply control circuit; 11, first switch module; 12, second switch module; R1, current limiting resistor; R2, discharge resistor; 13, first control unit; 14, second control unit; 20, external power supply; 30, external load. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0033] In the prior art, a power supply with a relatively high power is generally used to solve the problem that the inrush current generated when the electrical equipment is connected to the power supply is too large and triggers the overcurrent protection of the power supply, but this will significantly increase the cost. In order to solve this problem, the present application provides a power supply control circuit 10 and a power supply control device, which can be applied between an external load and an external power supply to provide timely and effective overcurrent protection for the external power supply.

[0034] For details, please refer to the attached Figure 1 An embodiment of the present application provides a power supply control circuit 10, which may include a first switch module 11, a second switch module 12, a current limiting resistor R1 and a discharge resistor R2.

[0035] More specifically, the power supply control circuit 10 is applied between an external power supply 20 and an external load 30, a first end of the current limiting resistor R1 is connected to the external power supply 20, and a second end of the current limiting resistor R1 is connected to the first switch module 11; at least one end of the discharge resistor R2 is connected to the first switch module 11; the first switch module 11 is also connected to the external load 30, and in a first state of the first switch module 11, the external load 30 and the discharge resistor R2 form a first loop; in a second state of the first switch module 11, the external power supply 20, the current limiting resistor R1 and the external load 30 form a second loop; a first end of the second switch module 12 is connected to a first end of the current limiting resistor R1, and a second end of the second switch module 12 is connected to the external load 30, and when the second switch module 12 is in an on state, the current limiting resistor R1 is short-circuited.

[0036] In particular, the external load 30 is a capacitive load, ie, a capacitor has the property of being able to store electrical energy and then release the electrical energy.

[0037] It should be noted that, with the help of the first circuit formed by the first switch module 11 in the first state and the second circuit formed in the second state, overcurrent protection can be achieved by connecting a current limiting resistor R1 between the external power supply 20 and the external load 30 when the external load 30 is powered on, and when the external load 30 is powered off, a discharge resistor R2 is connected at both ends of the external load 30 to quickly discharge the residual power of the external load 30; and by controlling whether the second switch module 12 is turned on, it is controlled whether the current limiting resistor R1 is short-circuited, so that the current limiting resistor R1 is not short-circuited during overcurrent protection, and the current limiting resistor R1 is short-circuited after the overcurrent protection is completed, thereby reducing energy loss.

[0038] The above preset time is based on the following formula:

[0039]

[0040] Among them, U is the voltage of the external power supply 20, Uc is the voltage across the external load 30; R is the resistance value of the current limiting resistor R1; C is the equivalent capacitance value in the external load 30; t is the time when the state of the first switch module 11 switches from the first state to the second state. Select a suitable load voltage Uc as the set voltage to determine the corresponding delay time t1. In addition, at time t=0, that is, the state of the first switch module 11 has just switched from the first state to the second state.

[0041] It is worth noting that, based on the following formula regarding the inrush current, in the same circuit, the inrush current in the circuit decreases as the time the external load 30 is connected to the external power source 20 increases.

[0042]

[0043] Among them, Ir is the current value of the impact current; U is the voltage of the external power supply 20, Uc is the voltage across the external load 30; R is the resistance value of the current limiting resistor R1; C is the equivalent capacitance value in the external load 30; t is the time when the state of the first switch module 11 switches from the first state to the second state.

[0044] It is worth noting that when the state of the first switch module 11 is switched from the second state to the first state, the relationship between the voltage across the external load 30 and time is:

[0045]

[0046] Among them, U is the voltage of the external power supply 20, Uc is the voltage across the external load 30; R2 is the resistance of the discharge resistor R2; C is the equivalent capacitance value in the external load 30; t is the time when the state of the first switch module 11 switches from the second state to the first state.

[0047] It is worth noting that the relationship between the current I2 flowing through the discharge resistor R2 and time is:

[0048]

[0049] Among them, U is the voltage of the external power supply 20, Uc is the voltage across the external load 30; R2 is the resistance of the discharge resistor R2; C is the equivalent capacitance value in the external load 30; t is the time when the state of the first switch module 11 switches from the second state to the first state.

[0050] In particular, when the state of the first switch module 11 is switched from the second state to the first state, that is, the external load 30 and the discharge resistor R2 form a first loop, the residual electric energy in the external load 30 is discharged with the help of the discharge resistor R2 to prevent the residual electric energy in the external load 30 from electric shocking the user.

[0051] In other embodiments of the present application, the first switch module 11 and the second switch module 12 respectively include a relay or multiple relays, or include a MOS switch circuit. The first switch module 11 and the second switch module 12 can be a relay or a relay group composed of multiple relays, or a MOS switch circuit composed of MOS tubes and other electronic components, or other modules / circuits / components with selective connection capabilities, which are not limited in the present application.

[0052] In other embodiments of the present application, the first switch module 11 includes a relay, the relay includes at least two static contacts, one static contact of the relay is connected to the second end of the current limiting resistor R1, at least one static contact of the relay is connected to at least one end of the discharge resistor R2, and the moving contact of the relay is connected to the external load 30. When the relay is in a first state, the external load 30 is connected to the discharge resistor R2; when the relay is in a second state, the current limiting resistor R1 is connected between the external power supply 20 and the external load 30.

[0053] It should be noted that, in the first state, the moving contact of the relay is connected to at least one static contact at the discharge resistor R2, so that the external load 30 and the discharge resistor R2 form a first loop, so that when the external load 30 is powered off, the electric energy in the external load 30 is released; in the second state, the moving contact of the relay is connected to the static contact at the second end of the current limiting resistor R1, and the external power supply 20, the current limiting resistor R1 and the external load 30 form a second loop, so that overcurrent protection is performed when the external power supply 20 supplies power to the external load 30. The relay can be controlled to switch the first switch module 11 between the first state and the second state to control the power supply state of the external load 30 and the external power supply 20.

[0054] In other embodiments of the present application, Figure 2 As shown, the relay of the first switch module 11 is a first relay, and the first relay has two moving contacts and four static contacts, that is, the first relay is a double-pole double-throw relay, the first end of the current-limiting resistor R1 is connected to the positive end of the external power supply 20, the first static contact of the first relay is connected to the second end of the current-limiting resistor R1, the second static contact of the first relay is connected to the first end of the discharge resistor R2, the third static contact of the first relay is connected to the negative end of the external power supply 20, and the fourth static contact of the first relay is connected to the second end of the discharge resistor R2;

[0055] The first moving contact of the first relay is connected to the positive end of the external load 30, and the second moving contact of the first relay is connected to the negative end of the external load 30. When the first relay is in the first state, the first moving contact of the first relay is connected to the second static contact of the first relay, and the second moving contact of the first relay is connected to the fourth static contact of the first relay, so that the external load 30 and the discharge resistor R2 form a first loop; when the first relay is in the second state, the first moving contact of the first relay is connected to the first static contact of the first relay, and the second moving contact of the first relay is connected to the third static contact of the first relay, so that the external power supply 20, the current limiting resistor R1 and the external load 30 form a second loop. Figure 2 In the embodiment, there is no direct connection between the external power source 20 and the external load 30, so complete electrical isolation is achieved, thereby improving the safety of the circuit.

[0056] In other embodiments of the present application, Figure 3 As shown, the relay of the first switch module 11 is a second relay, and the second relay has a moving contact and two static contacts, that is, the second relay is a single-pole double-throw relay, which has a simpler structure and lowers the cost. The first end of the current-limiting resistor R1 is connected to the positive end of the external power supply 20, the first static contact of the second relay is connected to the second end of the current-limiting resistor R1, the second static contact of the second relay is connected to the first end of the discharge resistor R2, and the second end of the discharge resistor R2 is connected to the negative end of the external load 30 and the negative end of the external power supply 20;

[0057] The moving contact of the second relay is connected to the positive end of the external load. When in the first state, the moving contact of the second relay is connected to the second static contact of the second relay, so that the external load 30 and the discharge resistor R2 form a first loop; when in the second state, the moving contact of the second relay is connected to the first static contact of the second relay, so that the external power supply 20, the current limiting resistor R1 and the external load 30 form a second loop.

[0058] In other embodiments of the present application, the first switch module 11 includes a third relay and a fourth relay, that is, the first switch module 11 is a relay group composed of a plurality of relays, the second end of the third relay and the second end of the fourth relay are both connected to the external load, and when the third relay and the fourth relay are in the first state, the external load 30 is connected to the discharge resistor R2; when the third relay and the fourth relay are in the second state, the current limiting resistor R1 is connected between the external power source 20 and the external load 30. The third relay and the fourth relay can be controlled to switch the first switch module 11 between the first state and the second state, so as to control the power supply state of the external load 30 and the external power source 20.

[0059] In other embodiments of the present application, Figure 4 As shown, the first switch module 11 includes a third relay and a fourth relay. In this embodiment, two single-pole single-throw relays are taken as an example for explanation. The second end of the third relay and the second end of the fourth relay are both connected to the external load 30, the first end of the third relay is connected to the discharge resistor R2, and the first end of the fourth relay is connected to the second end of the current limiting resistor R1.

[0060] In the first state, the third relay is disconnected and the fourth relay is turned on, so that the external load 30 and the discharge resistor R2 form a first loop; in the second state, the third relay is turned on, the fourth relay is disconnected, and the current limiting resistor R1 is connected between the external power supply 20 and the external load 30, so that the external power supply 20, the current limiting resistor R1 and the external load 30 form a second loop.

[0061] In other embodiments of the present application, Figure 5 As shown, the first switch module 11 includes a third relay and a fourth relay. In this embodiment, two single-pole double-throw relays are taken as an example for explanation. The moving contact of the third relay is connected to the positive end of the external load 30, the moving contact of the fourth relay is connected to the negative end of the external load 30, the first static contact of the third relay is connected to the second end of the current limiting resistor R1, the second static contact of the third relay is connected to the first end of the discharge resistor R2, the first static contact of the fourth relay is connected to the second end of the discharge resistor R2, and the second static contact of the fourth relay is connected to the negative end of the external power supply 20.

[0062] In the first state, the moving contact of the third relay is connected to the second static contact of the third relay, and the moving contact of the fourth relay is connected to the first static contact of the fourth relay, so that the external load 30 and the discharge resistor R2 form a first loop; in the second state, the moving contact of the third relay is connected to the first static contact of the third relay, and the moving contact of the fourth relay is connected to the second static contact of the fourth relay, and the current limiting resistor R1 is connected between the external power supply 20 and the external load 30, so that the external power supply 20, the current limiting resistor R1 and the external load 30 form a second loop.

[0063] In other embodiments of the present application, the power supply control circuit 10 also includes a first control unit 13 and a second control unit 14, the first control unit 13 is connected to the first switch module 11, and is used to control the first switch module 11 to switch between the first state and the second state based on a first control signal and a second control signal; the second control unit 14 is connected to the second switch module 12, and is used to control the second switch module 12 to be turned on based on a third control signal, and to control the second switch module 12 to be turned off based on a fourth control signal.

[0064] It should be noted that compared with manually directly switching the state of the first switch module 11 and the state of the second switch module 12, this solution automatically switches the state of the first switch module 11 and the state of the second switch module 12 based on various control signals by adding the first control unit 13 and the second control unit 14.

[0065] In other embodiments of the present application, the second control unit 14 is further improved, such as Figure 6 As shown, the second control unit 14 includes an AND gate and a comparator, the first input end of the AND gate is connected to the output end of the comparator, and the second input end of the AND gate receives the third control signal or the fourth control signal of the second switch module 12; the high potential end of the comparator receives the load voltage signal of the external load 30, and the low potential end of the comparator receives the preset reference voltage signal. That is, when the second control unit 14 receives the third control signal, and the value of the load voltage signal is higher than the value of the reference voltage signal, the second control unit 14 controls the second switch module 12 to switch the state of the second switch module 12 to the on state, so as to prevent the second switch module 12 from being turned on when the state of the first switch module 11 is the initial first state, so that the discharge resistor R2 is connected to the external power supply 20 to cause energy loss, or even burn out the discharge resistor R2.

[0066] It should be noted that the load voltage signal is a voltage signal obtained by sampling the voltage across the external load 30, or a feedback voltage signal sent by the controller to the high potential end of the comparator based on the voltage across the external load 30. The reference voltage signal is a preset stable voltage signal. The relationship between the load voltage signal and the reference voltage signal is as follows: when the external load 30 is connected to the external power supply 20, the value of the load voltage signal is higher than the value of the reference voltage signal, and the comparator outputs a high level; when the external load 30 is not connected to the external power supply 20, the value of the load voltage signal is lower than the value of the reference voltage signal, and the comparator outputs a low level. Only when the third control signal is received and the comparator outputs a high level, the second switch module will switch to the on state. When the first switch module is not switched to the second state, the value of the load voltage signal is always lower than the value of the reference voltage signal. Even if the controller mistakenly sends the second control signal, the second switch module will not be turned on.

[0067] In another embodiment of the present application, a power supply control device is provided, which is applied between an external power supply 20 and an external load 30, and the power supply control device includes: the above-mentioned power supply control circuit 10, and a controller electrically connected to the power supply control circuit 10, and the controller is used to generate a corresponding control signal to control the state switching of the first switch module 11 and the second switch module 12.

[0068] Therefore, by connecting the power supply device between the external power supply 20 and the external load 30, and by controlling the state switching of the first switch module 11 and the second switch module 12, when the external load 30 is using power, overcurrent protection can be achieved by connecting a current limiting resistor between the external power supply 20 and the external load 30, and when the external load 30 is powered off, a discharge resistor is connected at both ends of the external load to quickly discharge the residual power of the external load 30 to avoid electric shock to the user.

[0069] It is worth noting that the initial state of the second switch module 12 is the disconnected state, and the initial state of the first switch module 11 is the first state; the controller is used to generate a corresponding control signal to control the state switching of the first switch module 11 and the second switch module 12, specifically:

[0070] The controller is used to generate a first control signal to control the state of the first switch module 11 to switch to a second state when the external load 30 needs to be connected to the external power supply 20, so that the external power supply 20, the current limiting resistor R1 and the external load 30 form a second loop, and, after the connection time between the external load 30 and the external power supply 20 reaches a preset delay time, generate a third control signal to control the state of the second switch module 12 to switch to a conducting state to short-circuit the current limiting resistor R1; and,

[0071] The controller is also used to generate a fourth control signal to control the state of the second switch module 12 to be switched to a disconnected state when the external load 30 needs to be disconnected from the external power supply 20, and to generate a second control signal to control the state of the first switch module 11 to be switched to a first state, so that the external load 30 and the discharge resistor R2 form a first loop.

[0072] It should be noted that the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one external feature. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, device, product or equipment that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or equipment.

[0073] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more related listed items.

[0074] The technical features of the above embodiments can be combined without changing the basic principles of the present application. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of patent protection of the present application shall be subject to the attached claims.

Claims

1. A power supply control circuit, applied between an external power supply and an external load, characterized in that: It includes a first switch module, a second switch module, a current limiting resistor and a discharge resistor; The first end of the current limiting resistor is connected to the external power supply, and the second end of the current limiting resistor is connected to the first switch module; At least one end of the discharge resistor is connected to the first switch module; The first switch module is also connected to the external load. In a first state of the first switch module, the external load and the discharge resistor form a first loop; in a second state of the first switch module, the external power supply, the current limiting resistor and the external load form a second loop; The first end of the second switch module is connected to the first end of the current limiting resistor, and the second end of the second switch module is connected to the external load. When the second switch module is in an on state, the current limiting resistor is short-circuited.

2. The power supply control circuit according to claim 1, characterized in that: The first switch module and the second switch module respectively include one relay or multiple relays, or include MOSFET switch circuits.

3. The power supply control circuit according to claim 2, characterized in that: The first switch module includes a relay, which includes at least two static contacts, one static contact of the relay is connected to the second end of the current limiting resistor, at least one static contact of the relay is connected to at least one end of the discharge resistor, and the moving contact of the relay is connected to the external load. When the relay is in a first state, the external load is connected to the discharge resistor; when the relay is in a second state, the current limiting resistor is connected between the external power supply and the external load.

4. The power supply control circuit according to claim 3, characterized in that: The relay is a first relay, the first relay has two moving contacts and four static contacts, the first end of the current-limiting resistor is connected to the positive end of the external power supply, the first static contact of the first relay is connected to the second end of the current-limiting resistor, the second static contact of the first relay is connected to the first end of the discharge resistor, the third static contact of the first relay is connected to the negative end of the external power supply, and the fourth static contact of the first relay is connected to the second end of the discharge resistor; The first moving contact of the first relay is connected to the positive end of the external load, and the second moving contact of the first relay is connected to the negative end of the external load. When in a first state, the first moving contact of the first relay is connected to the second static contact of the first relay, and the second moving contact of the first relay is connected to the fourth static contact of the first relay, so that the external load and the discharge resistor form a first loop; when in a second state, the first moving contact of the first relay is connected to the first static contact of the first relay, and the second moving contact of the first relay is connected to the third static contact of the first relay, so that the external power supply, the current limiting resistor and the external load form a second loop.

5. The power supply control circuit according to claim 3, characterized in that: The relay is a second relay, the second relay has a moving contact and two static contacts, the first end of the current limiting resistor is connected to the positive end of the external power supply, the first static contact of the second relay is connected to the second end of the current limiting resistor, the second static contact of the second relay is connected to the first end of the discharge resistor, and the second end of the discharge resistor is connected to the negative end of the external load and the negative end of the external power supply; The moving contact of the second relay is connected to the positive end of the external load. When in a first state, the moving contact of the second relay is connected to the second static contact of the second relay, so that the external load and the discharge resistor form a first loop; when in a second state, the moving contact of the second relay is connected to the first static contact of the second relay, so that the external power supply, the current limiting resistor and the external load form a second loop.

6. The power supply control circuit according to claim 2, characterized in that: The first switch module includes a third relay and a fourth relay, wherein the second end of the third relay and the second end of the fourth relay are both connected to the external load, and when the third relay and the fourth relay are in a first state, the external load is connected to the discharge resistor; when the third relay and the fourth relay are in a second state, the current limiting resistor is connected between the external power supply and the external load.

7. The power supply control circuit according to claim 1, characterized in that: It also includes a first control unit and a second control unit, wherein the first control unit is connected to the first switch module and is used to control the first switch module to switch between the first state and the second state based on a first control signal and a second control signal; the second control unit is connected to the second switch module and is used to control the second switch module to be turned on based on a third control signal and to control the second switch module to be turned off based on a fourth control signal.

8. The power supply control circuit according to claim 7, characterized in that: The second control unit includes an AND gate and a comparator, the first input end of the AND gate is connected to the output end of the comparator, and the second input end of the AND gate receives the third control signal or the fourth control signal of the second switch module; the high potential end of the comparator receives the load voltage signal of the external load, and the low potential end of the comparator receives a preset reference voltage signal.

9. A power supply control device, applied between an external power source and an external load, characterized in that: The power supply control device comprises: a power supply control circuit as described in any one of claims 1 to 8, and a controller electrically connected to the power supply control circuit, wherein the controller is used to generate a corresponding control signal to control the state switching of the first switch module and the second switch module.

10. The power supply control device according to claim 9, characterized in that: The initial state of the second switch module is the disconnected state, and the initial state of the first switch module is the first state; the controller is used to generate a corresponding control signal to control the state switching of the first switch module and the second switch module, specifically: The controller is used to generate a first control signal to control the state of the first switch module to switch to a second state when the external load needs to be connected to the external power supply, so that the external power supply, the current limiting resistor and the external load form a second loop, and, after the connection time between the external load and the external power supply reaches a preset delay time, generate a third control signal to control the state of the second switch module to switch to an on state to short-circuit the current limiting resistor; and, The controller is also used to generate a fourth control signal to control the state of the second switch module to switch to a disconnected state when the external load needs to disconnect from the external power supply, and to generate a second control signal to control the state of the first switch module to switch to a first state, so that the external load and the discharge resistor form a first loop.

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