DC drive protection circuit, device and fan

Abstract

The present invention discloses a DC drive protection circuit, device and fan, belonging to the field of power electronic equipment, wherein the circuit comprises a drive module that is enabled according to a received load drive signal and outputs a drive signal; a switch module that controls the operation of the load according to the drive signal; a protection trigger module that is enabled according to the drive signal and outputs a protection trigger signal; and a voltage stabilization protection module that performs voltage stabilization protection according to the protection trigger signal. The present invention solves the problem in the prior art that the protection function of the DC load drive circuit easily causes the load to fail to start normally, and while taking into account the dual functions of load drive and local protection, achieves the effect of turning on the protection function after the load is running.

Description

Technical Field

[0001] The present invention relates to the field of power electronic equipment, and in particular to a direct current drive protection circuit, a device and a fan. Background Art

[0002] With the development of economy, various power electronic equipment have become common equipment in various industries. In existing power electronic equipment, DC fans are generally used for air cooling and heat dissipation. Correspondingly, it is necessary to design a drive circuit for the DC fan. Ways to provide protection for this DC drive circuit include using the short-circuit protection function of the auxiliary power supply and adding over-current and over-voltage protection functions in the drive circuit.

[0003] However, in the current method of adding overcurrent and overvoltage protection functions to the driving circuit, it is required that the protection function be triggered synchronously immediately when the fan is powered on, which may easily cause the fan to fail to start normally. Summary of the invention

[0004] The main purpose of the present invention is to provide a DC drive protection circuit, device and fan, aiming to solve the technical problem in the prior art that the protection function of the DC load drive circuit easily causes the load to fail to start normally.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a DC drive protection circuit, wherein an input end of the circuit is connected to a controller, and an output end is connected to a load, and the circuit comprises:

[0007] A driving module, a switch module and a protection trigger module respectively connected to the driving module, and a voltage stabilizing protection module connected to the protection trigger module; the driving module is connected to the controller, and the switch module and the voltage stabilizing protection module are respectively connected to the load; wherein,

[0008] The driving module is used to receive the load driving signal sent by the controller, and output the driving signal according to the load driving signal enable;

[0009] The switch module is used to control the load to work according to the driving signal;

[0010] The protection trigger module is used to output a protection trigger signal according to the driving signal enable;

[0011] The voltage stabilization protection module is used to perform voltage stabilization protection according to the protection trigger signal.

[0012] Optionally, in the above DC drive protection circuit, the circuit further includes an overcurrent protection module, and the overcurrent protection module is connected to the drive module and the switch module respectively;

[0013] The overcurrent protection module is used to control the switch module to be turned on or off according to the driving signal to perform overcurrent protection.

[0014] Optionally, in the above DC drive protection circuit, the circuit further includes an overvoltage protection module, and the overvoltage protection module is connected to the drive module and the protection trigger module respectively;

[0015] The overvoltage protection module is used to control the protection trigger module to enable according to the driving signal to perform overvoltage protection.

[0016] Optionally, in the above DC drive protection circuit, the drive module includes a photocoupler U1;

[0017] The first input end of the photoelectric coupler U1 is connected to the power supply and is connected to the second input end through the resistor R1, and the second input end is connected to the controller through the resistor R2; the first output end of the photoelectric coupler U1 is connected to the power supply through the resistor R3, and the second output end is grounded through the parallel capacitor C1 and the resistor R4, and the second output end is also connected to the switch module through the resistor R5.

[0018] Optionally, in the above DC drive protection circuit, the switch module includes a field effect transistor Q2;

[0019] The drain of the field effect transistor Q2 is connected to the load, the gate is connected to the driving module, and the source is grounded.

[0020] Optionally, in the above DC drive protection circuit, the protection trigger module includes a field effect transistor Q1;

[0021] The drain of the field effect transistor Q1 is connected to the voltage stabilizing protection module through a resistor R6, the gate is connected to the driving module, and the source is grounded through a resistor R7.

[0022] Optionally, in the above DC drive protection circuit, the overcurrent protection module includes a transistor Q4;

[0023] The collector of the transistor Q4 is connected to the driving module, the base is connected to the switch module and the sampling circuit respectively through a delay circuit composed of a resistor R9 and a capacitor C3, and the emitter is grounded; the sampling circuit includes a sampling resistor R10 and a capacitor C4 connected in parallel.

[0024] Optionally, in the above DC drive protection circuit, the overvoltage protection module includes a transistor Q3;

[0025] The collector of the transistor Q3 is connected to the driving module, the base is connected to the protection trigger module through a delay circuit composed of a resistor R8 and a capacitor C2, and the emitter is grounded.

[0026] In a second aspect, the present invention further provides a DC drive protection device, the device comprising:

[0027] Such as the DC drive protection circuit mentioned above;

[0028] A power supply providing working voltage and supply voltage to the DC drive protection circuit.

[0029] In a third aspect, the present invention further provides a fan, comprising:

[0030] Controller;

[0031] A circuit board is provided with the DC drive protection circuit as described above.

[0032] The above one or more technical solutions provided by the present invention may have the following advantages or at least achieve the following technical effects:

[0033] A DC drive protection circuit, device and fan proposed in the present invention adopt a drive module to receive a load drive signal sent by a controller and enable it, output a drive signal to a switch module, control the operation of the load, and realize load driving; and adopt a protection trigger module to enable it according to the drive signal, output a protection trigger signal to a voltage stabilization protection module, perform voltage stabilization protection, and trigger local protection after the load drive signal is enabled; the circuit of the present invention takes into account the dual functions of load driving and local protection, can meet the application requirements of turning on the protection function after the load is running, and avoids malfunctions such as the load being unable to start due to the immediate triggering of the protection function when the equipment is powered on. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0035] Figure 1 This is a connection diagram of a first embodiment of a DC drive protection circuit of the present invention;

[0036] Figure 2 The circuit schematic diagram of the DC drive protection circuit of the present invention;

[0037] Figure 3 FIG. 1 is a connection diagram of a second embodiment of a DC drive protection circuit of the present invention.

[0038] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0041] In the present invention, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a device or system including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such a device or system. In the absence of further restrictions, the elements defined by the sentence "includes..." do not exclude the existence of other identical elements in the device or system including the element. In addition, in the present invention, unless otherwise clearly specified and defined, the terms "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements.

[0042] In the present invention, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention, and they themselves have no specific meaning. Therefore, "module", "component" or "unit" can be used in a mixed manner. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] An analysis of the existing technology shows that in existing power electronic equipment, IGBT (Insulated Gate Bipolar Transistor) modules are mostly used for energy conversion. The high loss of IGBT modules can cause overheating, and DC fans are generally used for air cooling. Correspondingly, a drive circuit for the DC fan needs to be designed.

[0044] The existing DC fan drive circuit without speed feedback is designed based on the fan drive capability. The design is relatively simple and can only meet basic functions, but cannot take into account the fan local protection function. However, in practice, fan failure is inevitable, and it is necessary to provide protection for this DC drive circuit. The traditional way is to use the short-circuit protection function of the auxiliary power supply independent of the DC drive circuit to provide protection. The problem with this method is that when the fan fails, the short-circuit protection function of the auxiliary power supply is activated. At the same time, other drive circuits dependent on the short-circuit protection function will also be affected. Moreover, the short-circuit protection function of the auxiliary power supply is triggered immediately, and there is no fault response time, resulting in a large fault impact range.

[0045] At present, in the existing technology for adding protection functions to the driving circuit, there is a method of only adding an overcurrent protection function to provide protection. The problem with this method is that it cannot achieve overvoltage protection for the drain-source voltage of the field effect tube, which can easily cause damage to the field effect tube and the protection capability is insufficient; there is a method of adding overcurrent and overvoltage protection functions to provide protection. The problem with this method is that it requires the protection function to be triggered synchronously immediately when the fan is powered on, which can easily cause the fan to fail to start normally.

[0046] In view of the technical problem that the protection function of the DC load driving circuit in the prior art easily causes the load to fail to start normally, the present invention provides a DC driving protection circuit, and the overall idea is as follows:

[0047] The input end of the circuit is connected to the controller, and the output end is connected to the load. The circuit includes a driving module, a switch module and a protection trigger module respectively connected to the driving module, and a voltage stabilizing protection module connected to the protection trigger module; the driving module is connected to the controller, and the switch module and the voltage stabilizing protection module are respectively connected to the load; wherein the driving module is used to receive a load driving signal sent by the controller, and output a driving signal according to the load driving signal; the switch module is used to control the load operation according to the driving signal; the protection trigger module is used to enable according to the driving signal and output a protection trigger signal; the voltage stabilizing protection module is used to perform voltage stabilizing protection according to the protection trigger signal.

[0048] Through the above technical scheme, a driving module is adopted to receive the load driving signal sent by the controller and enable it, and output the driving signal to the switch module to control the operation of the load and realize load driving; a protection trigger module is also adopted to enable it according to the driving signal, and a protection trigger signal is output to the voltage stabilization protection module to perform voltage stabilization protection, so as to trigger local protection after the load driving signal is enabled; the circuit of the present invention takes into account the dual functions of load driving and local protection, and can meet the application requirements of turning on the protection function after the load is running, and avoids malfunctions such as the load being unable to start due to the immediate triggering of the protection function when the equipment is powered on.

[0049] Embodiment 1

[0050] Reference Figure 1 to Figure 2 , Figure 1 This is a connection diagram of the first embodiment of the DC drive protection circuit of the present invention. Figure 2 The circuit schematic diagram of the DC drive protection circuit of the present invention is as follows; this embodiment provides a DC drive protection circuit. The input end of the circuit is connected to the controller, and the output end is connected to the load. The circuit includes:

[0051] A driving module, a switch module and a protection trigger module respectively connected to the driving module, and a voltage stabilizing protection module connected to the protection trigger module; the driving module is connected to the controller, and the switch module and the voltage stabilizing protection module are respectively connected to the load; wherein,

[0052] The driving module is used to receive the load driving signal sent by the controller, and output the driving signal according to the load driving signal enable;

[0053] The switch module is used to control the load to work according to the driving signal;

[0054] The protection trigger module is used to output a protection trigger signal according to the driving signal enable;

[0055] The voltage stabilization protection module is used to perform voltage stabilization protection according to the protection trigger signal.

[0056] Specifically, the controller may be a control device or control panel corresponding to the load, an embedded processor, etc., which is a device that can send a load drive signal. The load may be a load driven and controlled by a DC voltage, such as a DC motor, a DC fan, etc. This embodiment is described in detail with a DC fan as the load.

[0057] Specifically, Figure 2 As shown, the driving module includes a photoelectric coupler U1;

[0058] The first input end of the photoelectric coupler U1 is connected to the power supply and is connected to the second input end through the resistor R1, and the second input end is connected to the controller through the resistor R2; the first output end of the photoelectric coupler U1 is connected to the power supply through the resistor R3, and the second output end is grounded through the parallel capacitor C1 and the resistor R4, and the second output end is also connected to the switch module through the resistor R5.

[0059] In this embodiment, the first input end of the photoelectric coupler U1 is connected to the power supply, and the power supply provides a +5V operating voltage. The first input end is also connected to the second input end through a resistor R1, and the second input end is connected to the controller through a resistor R2 to receive a load drive signal sent by the controller, that is, a fan drive signal; the first output end of the photoelectric coupler U1 is connected to the power supply through a resistor R3, and the power supply provides a +24V supply voltage. The second output end is grounded through a parallel capacitor C1 and a resistor R4, and is also connected to the switch module through a resistor R5. It should be noted that the resistance value of the resistor R5 can be set according to actual conditions.

[0060] Specifically, Figure 2 As shown, the switch module includes a field effect transistor Q2;

[0061] The drain of the field effect transistor Q2 is connected to the load, the gate is connected to the driving module, and the source is grounded.

[0062] In this embodiment, the drain of the field effect transistor Q2 is connected to the load, that is, connected to one end of the fan, the gate is connected to the driving module, specifically connected to the second output end of the photocoupler U1 in the driving module through the resistor R5, and the source is grounded.

[0063] Specifically, Figure 2 As shown, the protection trigger module includes a field effect transistor Q1;

[0064] The drain of the field effect transistor Q1 is connected to the voltage stabilizing protection module through a resistor R6, the gate is connected to the driving module, and the source is grounded through a resistor R7.

[0065] In this embodiment, both the field effect transistor Q1 and the field effect transistor Q2 are N-channel MOSFET tubes. The drain of the field effect transistor Q1 is connected to the voltage regulation protection module through the resistor R6, the gate is connected to the driving module, specifically to the second output end of the optocoupler U1 in the driving module, and the source is grounded through the resistor R7.

[0066] Specifically, Figure 2 As shown, the voltage stabilizing protection module includes a voltage stabilizing diode D1;

[0067] One end of the voltage stabilizing diode D1 is connected to the protection trigger module, and the other end is connected to a load. The load is connected to a power source.

[0068] In this embodiment, one end of the voltage regulator diode D1 is connected to the protection trigger module, specifically connected to the drain of the field effect transistor Q1 through the resistor R6, and the other end is connected to the load, specifically connected to the other end of the fan. The other end of the fan is also connected to the power supply, and the power supply provides a +24V power supply voltage to the fan.

[0069] During normal operation, after the load drive signal is enabled, the secondary side of the optocoupler U1 is turned on, and the voltage is divided by resistors R3 and R4, driving the field effect tube Q2 to turn on, providing a current channel for the load drive, and the load starts to run. At the same time, the field effect tube Q1 is driven to turn on, providing a working current channel for the voltage regulator diode D1. When the load fails, the drain and source of the field effect tube Q1 are over-voltage, triggering the voltage regulator protection, that is, the voltage regulator diode D1 is over-voltage and breaks down, and the field effect tube Q2 is sealed, realizing the field effect tube drain-source overvoltage protection under the fault state.

[0070] If the load drive signal is not enabled after the device is powered on, there is no voltage drop across the load, but it is close to the +24V power supply voltage, which is higher than the breakdown voltage of the Zener diode D1. In order to avoid the protection function being triggered and entering the protection state when the load drive signal is not enabled, so that the field effect tube Q2 is sealed, resulting in the load not being able to start normally, field effect tube Q1 is added to increase the first level of protection function trigger circuit, that is, the protection trigger module. In this way, only after the load drive signal is enabled, the secondary side of the optocoupler U1 is turned on, driving the field effect tube Q1 to turn on, the protection function will be triggered, which can avoid the circuit protection being mistakenly triggered after the device is powered on, resulting in the load not being able to start normally.

[0071] Since MOSFET is a voltage-type driver, the input impedance is large and the drive current is very small. When the circuit is working normally, the voltage drop on R5 is very small. At this time, the drive voltages of field effect tubes Q1 and Q2 are almost the same. The calculation formula of the drive voltage is:

[0072]

[0073] Therefore, in a specific implementation process, the values ​​of R3 and R4 can be specifically set to meet the driving voltage requirements of the field effect transistors Q1 and Q2.

[0074] In addition, in order to keep the protection circuit in a continuous protection state, the field effect tube Q1 can be kept turned on continuously. Specifically, the resistance value of the resistor R5 can be set to make the driving voltage of the field effect tube Q1 continue to meet the driving requirements, so that the protection circuit can be continuously protected. At this time, the calculation formula of the driving voltage of the field effect tube Q1 is:

[0075]

[0076] Therefore, in the specific implementation process, the value of R5 can also be specifically set to meet the driving voltage requirement of the field effect transistor Q1 so that the field effect transistor Q1 remains continuously turned on.

[0077] By adding resistor R5 to the driving module and setting its resistance value appropriately, it can be ensured that after the circuit protection is triggered, the driving voltage of the field effect transistor Q1 continues to meet the driving requirements, so that the protection circuit is continuously triggered and the equipment works reliably.

[0078] The DC drive protection circuit provided in this embodiment adopts a drive module to receive the load drive signal sent by the controller and enable it, outputs the drive signal to the switch module, controls the load operation, and realizes load driving; and also adopts a protection trigger module to enable according to the drive signal, outputs the protection trigger signal to the voltage stabilization protection module, performs voltage stabilization protection, and triggers local protection after the load drive signal is enabled; the circuit of the present invention takes into account the dual functions of load driving and local protection, can meet the application requirements of turning on the protection function after the load is running, and avoids malfunctions such as the load being unable to start due to the immediate triggering of the protection function when the device is powered on. While taking into account the dual functions of load driving and local protection, the effect of turning on the protection function after the load is running is achieved.

[0079] Embodiment 2

[0080] Reference Figure 2 and Figure 3 , Figure 3 This is a connection diagram of a second embodiment of a DC drive protection circuit of the present invention. Based on the first embodiment, this embodiment further proposes a DC drive protection circuit.

[0081] Furthermore, the circuit further comprises an overcurrent protection module, and the overcurrent protection module is connected to the driving module and the switch module respectively;

[0082] The overcurrent protection module is used to control the switch module to be turned on or off according to the driving signal to perform overcurrent protection.

[0083] Specifically, Figure 2 As shown, the overcurrent protection module includes a transistor Q4;

[0084] The collector of the transistor Q4 is connected to the driving module, the base is connected to the switch module and the sampling circuit respectively through a delay circuit composed of a resistor R9 and a capacitor C3, and the emitter is grounded; the sampling circuit includes a sampling resistor R10 and a capacitor C4 connected in parallel.

[0085] In this embodiment, the collector of the transistor Q4 is connected to the driving module, specifically connected to the second output end of the photoelectric coupler U1 in the driving module through the resistor R5, and the base is connected to the switch module and the sampling circuit respectively through the RC delay circuit composed of the resistor R9 and the capacitor C3, specifically connected to the source of the field effect transistor Q2 in the switch module, and the emitter is grounded. Specifically, the sampling circuit includes a sampling resistor R10 and a capacitor C4 connected in parallel.

[0086] Furthermore, the circuit further comprises an overvoltage protection module, and the overvoltage protection module is connected to the driving module and the protection triggering module respectively;

[0087] The overvoltage protection module is used to control the protection trigger module to enable according to the driving signal to perform overvoltage protection.

[0088] Specifically, Figure 2 As shown, the overvoltage protection module includes a transistor Q3;

[0089] The collector of the transistor Q3 is connected to the driving module, the base is connected to the protection trigger module through a delay circuit composed of a resistor R8 and a capacitor C2, and the emitter is grounded.

[0090] In this embodiment, both transistors Q3 and Q4 are NPN transistors; the collector of the transistor Q3 is connected to the driving module, specifically connected to the second output end of the photoelectric coupler U1 in the driving module through the resistor R5, and the base is connected to the protection trigger module through the RC delay circuit composed of the resistor R8 and the capacitor C2, specifically connected to the source of the field effect transistor Q1 in the protection trigger module, and the emitter is grounded.

[0091] By adding an RC delay circuit to the base of the transistor Q3, it is possible to prevent the overvoltage protection module from being falsely triggered after the fan drive signal is enabled but the fan has not yet started.

[0092] In this embodiment, a freewheeling diode D2 is connected in parallel at both ends of the load to eliminate the reverse voltage in the DC circuit caused by the sudden change of voltage and current at both ends of the inductive load, and protect the field effect tube Q2 of the switch module from being broken down or burned out.

[0093] In this embodiment, during normal operation, after the fan drive signal is enabled, the secondary side of the photocoupler U1 is turned on, and the voltage is divided by resistors R3 and R4, driving the field effect tube Q2 to turn on, providing a current channel for the fan drive, and the fan starts to run. At the same time, the field effect tube Q1 is driven to turn on, providing a working current channel for the voltage regulator diode D1. When the fan fails, the voltage regulator protection can be triggered to seal the field effect tube Q2.

[0094] During the operation of the fan, the field effect tube Q2 is in the on state. When the current in the circuit exceeds the preset current value, the sampling resistor R10 samples that the voltage at both ends rises and exceeds the voltage V between the base and emitter of the transistor Q4. BE , the transistor Q4 generates a reliable base current, the transistor Q4 is turned on, and the drive signal output by the drive module is pulled down, so that the field effect transistor Q2 is turned off, thus achieving over-current protection.

[0095] Considering that only adding the overcurrent protection module may form a dynamic equilibrium state due to the conduction of the transistor Q4 and the shutdown of the field effect tube Q2, that is, the field effect tube Q2 cannot be completely shut down. Although the current is not large, the high impedance can still easily cause the drain-source voltage V CE If the voltage is too high, the loss is still very large, and the FET Q2 is easily burned out. Therefore, in order to shut down the FET Q2 reliably, an overvoltage protection module is added as an overvoltage protection branch. Then, when the drain-source voltage V CE When it exceeds a certain value, the voltage-stabilizing diode D1 will be broken down, generating dynamic current, thereby turning on the transistor Q3, directly pulling down the drive signal input to the field effect transistor Q2, and turning off the field effect transistor Q2. In this way, through the overcurrent protection module and the overvoltage protection module, dual protection is achieved for the fan fault state, and this protection belongs to the local protection mechanism and will not affect other circuits. This dual protection mechanism achieves the effect of reliably turning off the field effect transistor.

[0096] If the fan drive signal is not enabled after the device is powered on, there is no voltage drop at both ends of the fan, but it is close to the +24V power supply voltage, and this potential is higher than the breakdown voltage value of the voltage-stabilizing diode D1. In order to avoid the overvoltage protection function being triggered and entering the protection state when the fan drive signal is not enabled, so that the field effect tube Q2 is sealed, resulting in the fan not being able to start normally, field effect tube Q1 is added to increase the first level of protection function trigger circuit, that is, the protection trigger module. In this way, only after the fan drive signal is enabled, the secondary side of the optocoupler U1 is turned on, and the driving field effect tube Q1 is turned on, the protection function will be triggered, that is, the overvoltage protection branch will be enabled. In this way, it can be avoided that the circuit protection is mistakenly triggered after the device is powered on, resulting in the fan not being able to start normally.

[0097] Since MOSFET is a voltage-type driver, the input impedance is large and the drive current is very small. When the circuit is working normally, the voltage drop on R5 is very small. At this time, the drive voltages of field effect tubes Q1 and Q2 are almost the same. The calculation formula of the drive voltage is:

[0098]

[0099] Therefore, in a specific implementation process, the values ​​of R3 and R4 can be specifically set to meet the driving voltage requirements of the field effect transistors Q1 and Q2.

[0100] As can be seen from the above, after the protection function of the circuit is triggered, the transistors Q3 and Q4 in the circuit will be turned on, and the driving signal of the field effect tube Q2 will be directly pulled down to a low level, but at this time the field effect tube Q1 needs to continue to be turned on to keep the protection circuit in a continuous protection state. To keep the field effect tube Q1 continuously turned on, the resistance value of the resistor R5 can be set to make the driving voltage of the field effect tube Q1 continue to meet the driving requirements, so that the protection circuit continues to protect. In this embodiment, the calculation formula for the driving voltage of the field effect tube Q1 is:

[0101]

[0102] Therefore, in the specific implementation process, the value of R5 can also be specifically set to meet the driving voltage requirement of the field effect transistor Q1 so that the field effect transistor Q1 remains continuously turned on.

[0103] When the device is powered on normally and the fan drive signal is enabled, the drive voltages of the field effect tubes Q1 and Q2 are the same, and the two MOSFETs are turned on at almost the same speed. However, the voltage regulator diode D1 breaks down very quickly, and there is still a possibility that the overvoltage protection module may be triggered quickly, that is, there is a possibility that the fan cannot start normally. In order to avoid the above situation, an RC delay circuit is added to the base of the transistor Q3 to delay the protection trigger signal, so that the field effect tube Q2 can quickly reduce the drain-source voltage V CE Pull it low to ensure that the overvoltage protection branch, that is, the overvoltage protection module is not triggered, and the fan can start normally.

[0104] The DC drive protection circuit provided in this embodiment takes into account the dual functions of fan driving and protection, and can realize local protection against fan faults. Compared with the traditional protection method, it no longer affects the operation of other circuits due to the protection function triggered by the auxiliary power supply, and can reduce the scope of fault impact. At the same time, it can meet the demand of turning on the protection function after the fan is running, and avoid malfunction caused by the protection function being triggered as soon as the equipment is powered on.

[0105] This embodiment can directly upgrade and optimize the existing load driving circuit to achieve multiple protections such as load short circuit, overcurrent and overvoltage. This multiple protection mechanism can not only reduce the scope of fault impact, but also avoid the situation where the load cannot start normally due to false triggering of protection.

[0106] Embodiment 3

[0107] This embodiment provides a DC drive protection device, which may include:

[0108] DC drive protection circuit;

[0109] A power supply providing working voltage and supply voltage to the DC drive protection circuit.

[0110] It should be noted that the specific structure of the DC drive protection circuit refers to the above embodiment. Since this embodiment adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0111] Embodiment 4

[0112] This embodiment provides a fan, which is a DC fan and may include:

[0113] Controller;

[0114] A circuit board provided with a DC drive protection circuit;

[0115] The controller generates a fan driving signal according to a control instruction input by a user, and sends the fan driving signal to the circuit board to drive the fan to work, and triggers local protection functions, namely short circuit, overvoltage and overcurrent protection functions, after the fan is running.

[0116] It should be noted that the specific structure of the DC drive protection circuit refers to the above embodiment. Since this embodiment adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0117] It should be noted that the serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments. The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the concept of the present invention, or directly or indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A DC drive protection circuit, wherein the input end of the circuit is connected to a controller, and the output end is connected to a load, characterized in that: The circuit comprises: A driving module, a switch module and a protection trigger module respectively connected to the driving module, and a voltage stabilizing protection module connected to the protection trigger module; the driving module is connected to the controller, and the switch module and the voltage stabilizing protection module are respectively connected to the load; wherein, The driving module is used to receive the load driving signal sent by the controller, and output the driving signal according to the load driving signal enable; The switch module is used to control the load to work according to the driving signal; The protection trigger module is used to output a protection trigger signal according to the driving signal enable; The voltage stabilization protection module is used to perform voltage stabilization protection according to the protection trigger signal; The driving module includes a photocoupler U1; The first input end of the photoelectric coupler U1 is connected to the power supply, and is connected to the second input end through the resistor R1, and the second input end is connected to the controller through the resistor R2; the first output end of the photoelectric coupler U1 is connected to the power supply through the resistor R3, and the second output end is grounded through the capacitor C1 and the resistor R4 connected in parallel, and the second output end is also connected to the switch module through the resistor R5; The protection trigger module includes a field effect transistor Q1; The drain of the field effect transistor Q1 is connected to the voltage stabilizing protection module through a resistor R6, the gate is connected to the driving module, and the source is grounded through a resistor R7.

2. The DC drive protection circuit according to claim 1, characterized in that: The circuit further comprises an overcurrent protection module, and the overcurrent protection module is connected to the driving module and the switch module respectively; The overcurrent protection module is used to control the switch module to be turned on or off according to the driving signal to perform overcurrent protection.

3. The DC drive protection circuit according to claim 1, characterized in that: The circuit further comprises an overvoltage protection module, and the overvoltage protection module is connected to the driving module and the protection triggering module respectively; The overvoltage protection module is used to control the protection trigger module to enable according to the driving signal to perform overvoltage protection.

4. The DC drive protection circuit according to claim 1, characterized in that: The switch module includes a field effect transistor Q2; The drain of the field effect transistor Q2 is connected to the load, the gate is connected to the driving module, and the source is grounded.

5. The DC drive protection circuit according to claim 2, characterized in that: The overcurrent protection module includes a transistor Q4; The collector of the transistor Q4 is connected to the driving module, the base is connected to the switch module and the sampling circuit respectively through a delay circuit composed of a resistor R9 and a capacitor C3, and the emitter is grounded; the sampling circuit includes a sampling resistor R10 and a capacitor C4 connected in parallel.

6. The DC drive protection circuit according to claim 3, characterized in that: The overvoltage protection module includes a transistor Q3; The collector of the transistor Q3 is connected to the driving module, the base is connected to the protection trigger module through a delay circuit composed of a resistor R8 and a capacitor C2, and the emitter is grounded.

7. A DC drive protection device, characterized in that: The device comprises: A DC drive protection circuit as claimed in any one of claims 1 to 6; A power supply providing working voltage and supply voltage to the DC drive protection circuit.

8. A fan, characterized in that: The fan comprises: Controller; A circuit board provided with a DC drive protection circuit as claimed in any one of claims 1 to 6.

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