CN113839368A - Load protection circuit and power supply equipment - Google Patents
Load protection circuit and power supply equipment Download PDFInfo
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- CN113839368A CN113839368A CN202110953437.7A CN202110953437A CN113839368A CN 113839368 A CN113839368 A CN 113839368A CN 202110953437 A CN202110953437 A CN 202110953437A CN 113839368 A CN113839368 A CN 113839368A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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Abstract
The invention discloses a load protection circuit and power supply equipment, the load protection circuit includes: the output detection module is used for being connected with the power supply equipment and the load and sampling the current of the load to obtain a sampling current; the positive feedback module is connected with the output detection module and is used for being connected with the enabling end of the power supply equipment, and if the sampling current is larger than the preset current, the positive feedback module controls the enabling end of the power supply equipment to be at a low level so as to stop the power supply equipment; and the maintaining module is connected with the positive feedback module and is used for keeping the enabling end of the power supply equipment at a low level so as to continuously stop the power supply equipment. Therefore, the invention can rapidly protect the load and the power supply equipment from being damaged in real time by detecting the current connected to the load in real time, and can enable the power supply equipment to maintain the state of stopping working through the maintaining module, thereby ensuring that the power supply equipment and the load are not damaged and improving the safety.
Description
Technical Field
The invention relates to the technical field of load overcurrent protection, in particular to a load protection circuit and power supply equipment.
Background
In the production process of electronic products, the condition of overlarge load current often appears, even short circuit is a common phenomenon, the consequence caused by overlarge load current and short circuit is light, equipment can be damaged, and the consequence is burnt out even a fire is caused, so that certain potential safety hazard is realized. Therefore, load overcurrent protection is a very important measure.
Wherein, in the production process of current electronic product, test or inspection all need frequent access to be used for providing the external device of power or signal, and the access of these external devices is all gone on through the plug-in components, and the repeated plug-in of these plug-in components produces wearing and tearing very easily, can cause the impedance between the foot to reduce, leads to external device to take place the short circuit, the load takes place the condition that overflows to damage external device and load.
Accordingly, the prior art is yet to be improved and developed.
Disclosure of Invention
In view of the above-mentioned deficiencies of the prior art, an object of the present invention is to provide a load protection circuit and a power device, so as to solve the problem of damage to an external device and a load caused by a short circuit of the external device and an overcurrent of the load when the external device is connected to the external device for testing or inspecting in the production process of the conventional electronic product.
The technical scheme of the invention is as follows:
a load protection circuit, comprising:
the output detection module is used for being connected with the power supply equipment and the load and sampling the current of the load to obtain a sampling current;
the positive feedback module is connected with the output detection module and is used for being connected with an enabling end of the power supply equipment, and if the sampling current is greater than a preset current, the positive feedback module controls the enabling end of the power supply equipment to be at a low level so as to stop the power supply equipment;
and the maintaining module is connected with the positive feedback module and is used for keeping the enabling end of the power supply equipment at a low level so as to continuously stop the power supply equipment.
In a further aspect of the present invention, the output detection module comprises: a first resistor; one end of the first resistor is connected with a power supply device and the positive feedback module respectively, and the other end of the first resistor is connected with the positive feedback module and the load respectively.
In a further aspect of the present invention, the output detection module comprises: a second resistor and a third resistor; one end of the second resistor is connected with a power supply device and the positive feedback module respectively, and the other end of the second resistor is connected with the positive feedback module and the load respectively; the third resistor is connected in parallel with the second resistor.
In a further aspect of the present invention, the positive feedback module comprises: the first switch tube, the second switch tube, the first capacitor and the first voltage division unit; an emitting electrode of the first switching tube is connected with one end of the first resistor, a base electrode of the first switching tube is connected with the other end of the first resistor, and a collector electrode of the first switching tube is connected with the first voltage division unit; the first capacitor is respectively connected with the first voltage division unit and the base electrode of the second switch tube, and the other end of the first capacitor is grounded; and the collector electrode of the second switch tube is respectively connected with the holding module and the enabling end of the power supply equipment, and the emitter electrode of the second switch tube is grounded.
In a further aspect of the present invention, the first voltage division unit includes: a third resistor and a fourth resistor; one end of the third resistor is connected with the collector of the first switch tube, the other end of the third resistor is connected with one end of the fourth resistor and the base of the second switch tube, and the other end of the fourth resistor is connected with the emitter of the second switch tube.
In a further aspect of the invention, the holding module comprises: the third switching tube, the fifth resistor and the second voltage division unit; the collector of the third switching tube is connected with the base of the second switching tube, the base of the third switching tube is connected with the second voltage division unit, the emitter of the third switching tube is connected with one end of the fifth resistor, and the other end of the fifth resistor is connected with the voltage division unit and is connected with a power supply; the second voltage division unit is also connected with a collector of the second switch tube.
In a further aspect of the present invention, the second voltage division unit includes: a sixth resistor and a seventh resistor; one end of the sixth resistor is connected with one end of the fifth resistor and the power supply voltage respectively, and the other end of the sixth resistor is connected with one end of the seventh resistor and the common connection end of the base of the third switching tube; the other end of the seventh resistor is connected with the collector of the second switching tube.
In a further aspect of the present invention, the load protection circuit further comprises: a first diode; the anode of the first diode is connected with an enabling end of power supply equipment, and the cathode of the first diode is connected with the second voltage division unit.
According to the further arrangement of the invention, the first switching tube and the third switching tube are both PNP type triodes; the second switch tube is an NPN type triode.
Based on the same inventive concept, the present invention also provides a power supply apparatus, including:
a circuit board; and
as described above, the load protection circuit is disposed on the circuit board.
The invention provides a load protection circuit and power supply equipment, wherein the load protection circuit comprises: the output detection module is used for being connected with the power supply equipment and the load and sampling the current of the load to obtain a sampling current; the positive feedback module is connected with the output detection module and is used for being connected with an enabling end of the power supply equipment, and if the sampling current is greater than a preset current, the positive feedback module controls the enabling end of the power supply equipment to be at a low level so as to stop the power supply equipment; and the maintaining module is connected with the positive feedback module and is used for keeping the enabling end of the power supply equipment at a low level so as to continuously stop the power supply equipment. The invention detects the current connected to the load through the output detection module, controls the enabling end of the power supply equipment to be at a low level through the positive feedback module when the sampling current is higher than the preset current, and controls the enabling end of the power supply equipment to be maintained at the low level through the holding module at the moment, so that the power supply equipment cannot output power supply voltage. Therefore, the invention can control the enabling end of the power supply equipment to be low level when detecting the current overload by detecting the current accessed to the load in real time, so as to stop the power supply equipment, thereby quickly protecting the load and the power supply equipment from being damaged in real time, and once the protection is started, the power supply equipment can maintain the state of stopping working through the maintaining module until the abnormal load is removed, so that the power supply equipment and the load can not be damaged, and the safety is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a functional block architecture diagram of a load protection circuit in the present invention.
Fig. 2 is a circuit schematic of the load protection circuit of the present invention.
The various symbols in the drawings: 100. an output detection module; 200. a positive feedback module; 201. a first voltage division unit; 300. a holding module; 301. and a second voltage division unit.
Detailed Description
The invention provides a load protection circuit and power supply equipment, wherein the load protection circuit can be applied to module burn-in equipment (internal screen supply voltage is 12V output) and power supply of a core test rack (voltage for supplying a main board is 12V/24V). In the production, debugging and aging of a television (a module or a mainboard), because the input (power supply) of an external power supply is frequent, and the access is carried out through connectors, the repeated plugging and unplugging of the connectors are easy to wear, so that the impedance between pins is reduced and even short circuit is caused, the invention effectively prevents the occurrence of load overcurrent and better protects the input power supply equipment from being damaged.
In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the embodiments and claims, the articles "a", "an", "the" and "the" may include plural forms as well, unless the context specifically dictates otherwise. If there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.
It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The inventor researches and discovers that in the production process of the existing electronic product, the test or inspection needs to frequently access the external equipment for providing power supply or signals, the access of the external equipment is carried out through the plug-in units, the plug-in units are repeatedly plugged and pulled out and easily generate abrasion, the impedance between pins is reduced, the external equipment is short-circuited, and the load is over-current, so that the external equipment and the load are damaged. At present, there are many schemes for solving load overcurrent protection, for example, a single chip microcomputer can be used for detecting the current of a load, however, the output is cut off by the operation output instruction of the single chip microcomputer, so that the delay is achieved, the power supply equipment cannot be stopped working quickly in real time, the possibility of damage of the power supply equipment and the load still exists, and a fuse fusing protection measure can be further adopted, that is, once the load is abnormal, the fuse of the external equipment (the input power supply equipment) can be fused, so that the external equipment needs to be disassembled to replace the fuse, that is, the external equipment needs to be overhauled, the fuse fusing protection measure has the defects that the fuse fusing protection measure cannot be recovered, manual operation needs to be added, the workload is increased, and the fuse fusing also has certain lag, and the external equipment cannot be safely and effectively protected.
In view of the above technical problems, the present invention provides a load protection circuit and a power supply device, which perform real-time detection on a current accessed to a load, and when a current overload is detected, control an enabling terminal of the power supply device to be a low level to stop the power supply device from working, so that the load and the power supply device can be quickly protected from being damaged in real time.
Referring to fig. 1 to fig. 2, the present invention provides a preferred embodiment of a load protection circuit.
As shown in fig. 1, the load protection circuit provided by the present invention is applied to a power supply device, wherein the load protection circuit includes: output detection module 100, positive feedback module 200 and holding module 300, output detection module 100 is used for being connected with power equipment and load to the electric current to the load is sampled in order to obtain sampling current, positive feedback module 200 with output detection module 100 is connected for be connected with power equipment's enable end, if sampling current is greater than preset current, then positive feedback module 200 control power equipment's enable end is the low level, so that power equipment stops working, holding module 300 is connected with positive feedback module 200, holding module 300 is used for making power equipment's enable end keep the low level, so that power equipment continues to stop working.
Specifically, the load is a product to be tested or inspected, and the power supply device is used for supplying power supply voltage to the load so as to test and detect the load. The power supply device is provided with an enabling end, namely a control end, and the power supply device can be controlled to stop or start working by controlling the level of the enabling end of the power supply device, for example, when the enabling end of the power supply device is at a low level, the power supply device is in a state of stopping working.
The input end of the output detection module 100 is connected with a power supply device, the output end of the output detection module 100 is electrically connected with a load, power supply voltage output by the power supply device is output to the load after passing through the output detection module 100 to supply power to the load, the current sampled by the output detection module 100 is the current of the load, and the output detection module 100 samples the power supply voltage output by the power supply device in real time. The positive feedback module 200 is electrically connected to the output detection module 100 and the enable terminal of the power supply device, and when the current collected by the output detection module 100 is greater than the preset current, the positive feedback module 200 controls the enable terminal of the power supply device to be at a low level, so that the power supply device stops working and no longer supplies power to the load. In addition, the maintaining module 300 is connected to the positive feedback module 200 to continuously supply power to the positive feedback module 200, so that the enable terminal of the power supply device continuously maintains a low level, and then the power supply device also continues to be in a stop state and will not recover. In addition, the load protection circuit provided by the invention is composed of all electronic elements, and has the advantages of low cost, simple structure and wide universality.
Therefore, the invention carries out real-time detection on the current accessed to the load, controls the enabling end of the power supply equipment to be at a low level when detecting the current overload, so as to stop the power supply equipment from working, carries out protection by a positive feedback principle, and basically has no time delay in the process, thereby being capable of quickly protecting the load and the power supply equipment from being damaged in real time. Moreover, once the protection is started, the power supply device can maintain the state of stopping working through the retaining module 300, and the power supply device can normally work until the abnormal load is removed, so that the power supply device and the load are not damaged, and the safety is improved.
Referring to fig. 1 and 2, in a further implementation of an embodiment, the output detection module 100 includes: a first resistor R1; one end of the first resistor R1 is connected to the power supply device and the positive feedback module 200, and the other end of the first resistor R1 is connected to the positive feedback module 200 and the load.
Specifically, the first resistor R1 is a sampling resistor, and the first resistor R1 is connected between the power supply device and the load to sample the current of the load and obtain a sampled current.
Referring to fig. 2, in a further implementation of an embodiment, the positive feedback module 200 includes: the first switch tube Q1, the second switch tube Q2, the first capacitor C1 and the first voltage division unit 201; wherein an emitter of the first switching tube Q1 is connected to one end of the first resistor R1, a base of the first switching tube Q1 is connected to the other end of the first resistor R1, and a collector of the first switching tube Q1 is connected to the first voltage dividing unit 201; the first capacitor C1 is connected to the first voltage divider 201 and the base of the second switch Q2, respectively, and the other end of the first capacitor C1 is grounded; the collector of the second switch Q2 is connected to the holding module 300 and the enable terminal of the power supply device, and the emitter of the second switch Q2 is grounded.
Specifically, the first switch Q1 is a PNP transistor, the second switch Q2 is an NPN transistor, and an emitter of the first switch Q1 is connected to one end of the first resistor R1. When the voltage between the emitter and the base of the first switch tube Q1 is greater than or equal to 0.7V, the first switch tube Q1 is turned on (the preset current is the on current of the first switch tube Q1), that is, Veb is greater than or equal to 9.7V. Since the voltage difference V1 ═ I × R1 across the first resistor R1, that is, when V1 is greater than 0.7V, the first switching tube Q1 is turned on, that is, the whole protection circuit starts to operate, and the user can calculate the resistance value of the first resistor R1 and the required power according to the maximum current allowed by the load.
For example, the maximum allowable current of the load is set to be 4A, and if the maximum allowable current is greater than 4A, the load is considered to be abnormal, and protection is required.
According to the formula: and U ═ I × R, and substituting the values to obtain: 0.7-4 × R1, R1-0.175 ohms, according to the power formula: p ═ I ═ R1 ═ 2.8W, i.e.: the parameters selected for R1 are: 0.175 ohms/2.8W.
According to the above calculation, when the load exceeds the current allowed by the setting, the first switch tube Q1 is turned on, the voltage (divided voltage) output by the power voltage Vout after passing through the first voltage dividing unit 201 is output to the base of the second switch tube Q2, wherein the voltage output by the first voltage dividing unit 201 is greater than the Vbe turn-on voltage of the second switch tube Q2, and when the voltage output by the first voltage dividing unit 201 turns on and saturates the second switch tube Q2, the collector of the second switch tube Q2 is at a low level, so that the enable terminal connected to the collector of the second switch tube Q2 is at a low level, thereby the power supply device can stop operating. Therefore, the invention detects the current accessed by the load in real time through the first resistor R1, and when the current overload is detected, the enabling end of the power supply equipment can be controlled to be at low level, so that the power supply equipment stops working, and the process basically has no time delay, thereby being capable of quickly protecting the load and the power supply equipment from being damaged in real time.
The first capacitor C1 is connected to the base of the first voltage divider 201 and the base of the second switch Q2, and the other end is grounded, so as to prevent the second switch Q2 from being operated by high frequency interference.
In a further embodiment of an embodiment, with reference to fig. 2, the first voltage dividing unit 201 includes: a third resistor R3 and a fourth resistor R4; one end of the third resistor R3 is connected to the collector of the first switching transistor Q1, the other end of the third resistor R3 is connected to one end of the fourth resistor R4 and the base of the second switching transistor Q2, and the other end of the fourth resistor R4 is connected to the emitter of the second switching transistor Q2.
Specifically, the third resistor R3 and the fourth resistor R4 form the first voltage dividing unit 201, and in specific implementation, the ratio of R3/R4 may be reasonably designed according to the power voltage Vout output by the power device, so that the divided voltage can be greater than the Vbe conducting voltage of the second transistor Q2, and thus the collector of the second switch transistor Q2 can be at a low level to control the enable terminal of the power device to be in a low level state.
In some embodiments, the output detection module 100 may be further configured to: a second resistor R2 and a third resistor R3; one end of the second resistor R2 is connected to a power supply device and the positive feedback module 200, and the other end of the second resistor R2 is connected to the positive feedback module 200 and a load; the third resistor R3 is connected in parallel with the second resistor R2.
Specifically, in practical application, the current of the load may be sampled by a method of reducing the power of the resistors, that is, the first resistor R1 may be split into two or more resistors connected in parallel, and it is only necessary that the total resistance value after the parallel connection is kept unchanged, for example, the total resistance value after the parallel connection of the second resistor R2 and the third resistor R3 is equal to the resistance value of the first resistor R1, but the power of each resistor after the parallel connection may be reduced to general, for example, when the allowable current of the load is 4A, the power of the first resistor R1 is 2.8W, and then the power of a single resistor may be reduced to half and 1.4W after the parallel connection of the second resistor R2 and the third resistor R3.
Referring to fig. 2, in a further implementation of an embodiment, the holding module 300 includes: the third switching tube Q3, the fifth resistor R5 and the second voltage division unit 301; a collector of the third switching tube Q3 is connected to a base of the second switching tube Q2, a base of the third switching tube Q3 is connected to the second voltage dividing unit 301, an emitter of the third switching tube Q3 is connected to one end of the fifth resistor Q5, and the other end of the fifth resistor Q5 is connected to the second voltage dividing unit 301 and is connected to a power supply; the second voltage divider 301 is further connected to a collector of the second switching tube Q2.
Specifically, the third switch tube Q3 is a PNP type triode, the fifth resistor R5 is a current-limiting resistor, the fifth resistor R5 is connected between the emitter of the third switch tube Q3 and the power supply, the collector of the third switch tube Q3 is connected to the base of the second switch tube Q2, when the third switch tube Q3 is turned on in saturation, the power supply voltage VCC is added to the base of the second switch tube Q2 through the fifth resistor R5, so that the base current of the second switch tube Q2 is not too large to burn the second switch tube Q2. The base of the third switching tube Q3 is connected to the second voltage dividing unit 301, the other end of the fifth resistor R5 is connected to the second voltage dividing unit 301 and to the power supply, the second voltage dividing unit 301 is connected to the collector of the second switching tube Q2, when the second switching tube Q2 is turned on and saturated, the second voltage dividing unit 301 divides the power supply voltage VCC and makes the voltage Veb between the emitter and the base of the third switching tube Q3 greater than 0.7V, so that the third switching tube Q3 can be turned on, and when the third switching tube Q3 is turned on and saturated, the power supply voltage VCC is continuously applied to the base of the second switching tube Q2, so that the base of the second switching tube Q2 is clamped at a high level, so that the second switching tube Q2 is continuously turned on and is not affected by the connected load terminal, so that the enabling terminal of the power supply apparatus can be kept at a low level, and further the power supply equipment is locked, so that the power supply equipment can be continuously stopped and can not be recovered. Therefore, the present invention connects the maintaining module 300 with the positive feedback module 200 to continuously supply power to the positive feedback module 200, so that the enabling end of the power supply device continuously maintains a low level, and then the power supply device also continues to be in a stop state and will not recover.
Referring to fig. 2, in a further implementation manner of an embodiment, the second voltage dividing unit 301 includes: a sixth resistor R6 and a seventh resistor R7; one end of the sixth resistor R6 is connected to one end of the fifth resistor R5 and the supply voltage VCC, respectively, and the other end of the sixth resistor R6 is connected to one end of the seventh resistor R7 and the common connection end of the base of the third switching transistor R3; the other end of the seventh resistor R7 is connected to the collector of the second switch Q2.
Specifically, the sixth resistor R6 and the seventh resistor R7 constitute the second voltage dividing unit 301, and when the second switching tube Q2 is in saturation conduction, the sixth resistor R6 and the seventh resistor R7 divide the power supply voltage VCC, and make the divided voltage greater than 0.7V, so as to make the third switching tube Q3 in conduction and saturation, thereby making the base of the second switching tube Q2 clamped at a high level. In some embodiments, the sixth resistor R6 and the seventh resistor R7 have the same resistance, that is, the divided voltage value after voltage division is 1/2VCC, where the divided voltage value may be reasonably calculated according to the value of the supply voltage VCC, for example, VCC may be set to 3.3V, and then the divided voltage value is 1.65V.
Referring to fig. 2, in a further implementation manner of an embodiment, the load protection circuit further includes: a first diode D1; wherein the anode of the first diode D1 is connected to the enable terminal of the power supply device, and the cathode of the first diode D1 is connected to the second voltage dividing unit 301.
Specifically, when the second switch tube Q2 is turned off, no current flows through the second voltage dividing unit 301, when the second switch tube Q2 is turned on and saturated, the second voltage dividing unit 301 starts to divide the voltage, the first diode D1 is disposed between the second voltage dividing unit 301 and the enable terminal of the power supply device, and when the second switch tube Q2 is turned off, the power supply voltage VCC can be prevented from flowing back to the enable terminal of the power supply device through the second voltage dividing unit 301.
Referring to fig. 1 and fig. 2, based on the same inventive concept, the present invention further provides a power supply apparatus, which includes: a circuit board; and the load protection circuit is arranged on the circuit board. Wherein the load protection circuit includes: output detection module 100, positive feedback module 200 and holding module 300, output detection module 100 is used for being connected with power equipment and load to the electric current of load is sampled in order to obtain sampling current, positive feedback module 200 with output detection module 100 is connected, and is used for being connected with power equipment's enable end, if sampling current is greater than preset current, positive feedback module 200 control power equipment's enable end is the low level, so that power equipment stops working, holding module 300 is connected with positive feedback module 200, holding module 300 is used for making power equipment's enable end keep the low level, so that power equipment keeps stopping working.
In the embodiment, the current connected to the load is detected in real time, when the current overload is detected, the enabling end of the power supply equipment is controlled to be at a low level, so that the power supply equipment stops working, the protection is performed through a positive feedback principle, the process basically has no time delay, and the load and the power supply equipment can be rapidly protected from being damaged in real time. Moreover, once the protection is started, the power supply device can maintain the state of stopping working through the retaining module 300, and the power supply device can normally work until the abnormal load is removed, so that the power supply device and the load are not damaged, and the safety is improved.
In summary, the present invention provides a load protection circuit and a power supply apparatus, where the load protection circuit includes: the output detection module is used for being connected with the power supply equipment and the load and sampling the current of the load to obtain a sampling current; the positive feedback module is connected with the output detection module and is used for being connected with an enabling end of the power supply equipment, and if the sampling current is greater than a preset current, the positive feedback module controls the enabling end of the power supply equipment to be at a low level so as to stop the power supply equipment; and the maintaining module is connected with the positive feedback module and is used for keeping the enabling end of the power supply equipment at a low level so as to continuously stop the power supply equipment. The invention detects the current connected to the load through the output detection module, controls the enabling end of the power supply equipment to be at a low level through the positive feedback module when the sampling current is higher than the preset current, and controls the enabling end of the power supply equipment to be maintained at the low level through the holding module at the moment, so that the power supply equipment cannot output power supply voltage. Therefore, the invention can control the enabling end of the power supply equipment to be low level when detecting the current overload by detecting the current accessed to the load in real time, so as to stop the power supply equipment, thereby quickly protecting the load and the power supply equipment from being damaged in real time, and once the protection is started, the power supply equipment can maintain the state of stopping working through the maintaining module until the abnormal load is removed, so that the power supply equipment and the load can not be damaged, and the safety is improved.
It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.
Claims (10)
1. A load protection circuit, comprising:
the output detection module is used for being connected with the power supply equipment and the load and sampling the current of the load to obtain a sampling current;
the positive feedback module is connected with the output detection module and is used for being connected with an enabling end of the power supply equipment, and if the sampling current is greater than a preset current, the positive feedback module controls the enabling end of the power supply equipment to be at a low level so as to stop the power supply equipment;
and the maintaining module is connected with the positive feedback module and is used for keeping the enabling end of the power supply equipment at a low level so as to continuously stop the power supply equipment.
2. The load protection circuit of claim 1, wherein the output detection module comprises: a first resistor; one end of the first resistor is connected with a power supply device and the positive feedback module respectively, and the other end of the first resistor is connected with the positive feedback module and the load respectively.
3. The load protection circuit of claim 1, wherein the output detection module: a second resistor and a third resistor; one end of the second resistor is connected with a power supply device and the positive feedback module respectively, and the other end of the second resistor is connected with the positive feedback module and the load respectively; the third resistor is connected in parallel with the second resistor.
4. The load protection circuit of claim 2, wherein the positive feedback module comprises: the first switch tube, the second switch tube, the first capacitor and the first voltage division unit; an emitting electrode of the first switching tube is connected with one end of the first resistor, a base electrode of the first switching tube is connected with the other end of the first resistor, and a collector electrode of the first switching tube is connected with the first voltage division unit; the first capacitor is respectively connected with the first voltage division unit and the base electrode of the second switch tube, and the other end of the first capacitor is grounded; and the collector electrode of the second switch tube is respectively connected with the holding module and the enabling end of the power supply equipment, and the emitter electrode of the second switch tube is grounded.
5. The load protection circuit of claim 4, wherein the first voltage division unit comprises: a third resistor and a fourth resistor; one end of the third resistor is connected with the collector of the first switch tube, the other end of the third resistor is connected with one end of the fourth resistor and the base of the second switch tube, and the other end of the fourth resistor is connected with the emitter of the second switch tube.
6. The load protection circuit of claim 4, wherein the retention module comprises: the third switching tube, the fifth resistor and the second voltage division unit; the collector of the third switching tube is connected with the base of the second switching tube, the base of the third switching tube is connected with the second voltage division unit, the emitter of the third switching tube is connected with one end of the fifth resistor, and the other end of the fifth resistor is connected with the voltage division unit and is connected with a power supply; the second voltage division unit is also connected with a collector of the second switch tube.
7. The load protection circuit of claim 6, wherein the second voltage division unit comprises: a sixth resistor and a seventh resistor; one end of the sixth resistor is connected with one end of the fifth resistor and the power supply voltage respectively, and the other end of the sixth resistor is connected with one end of the seventh resistor and the common connection end of the base of the third switching tube; the other end of the seventh resistor is connected with the collector of the second switching tube.
8. The load protection circuit of claim 6, further comprising: a first diode; the anode of the first diode is connected with an enabling end of power supply equipment, and the cathode of the first diode is connected with the second voltage division unit.
9. The load protection circuit according to claim 6, wherein the first switching tube and the third switching tube are both PNP type triodes; the second switch tube is an NPN type triode.
10. A power supply apparatus, characterized by comprising:
a circuit board; and
the load protection circuit of any of claims 1-9, disposed on the circuit board.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110953437.7A CN113839368A (en) | 2021-08-19 | 2021-08-19 | Load protection circuit and power supply equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110953437.7A CN113839368A (en) | 2021-08-19 | 2021-08-19 | Load protection circuit and power supply equipment |
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| Publication Number | Publication Date |
|---|---|
| CN113839368A true CN113839368A (en) | 2021-12-24 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110953437.7A Pending CN113839368A (en) | 2021-08-19 | 2021-08-19 | Load protection circuit and power supply equipment |
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| CN (1) | CN113839368A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115993480A (en) * | 2023-03-23 | 2023-04-21 | 苏州锴威特半导体股份有限公司 | Overcurrent detection circuit for bridge type driving circuit |
-
2021
- 2021-08-19 CN CN202110953437.7A patent/CN113839368A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115993480A (en) * | 2023-03-23 | 2023-04-21 | 苏州锴威特半导体股份有限公司 | Overcurrent detection circuit for bridge type driving circuit |
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