CN110739665A - Protection circuit and switching power supply - Google Patents
Protection circuit and switching power supply Download PDFInfo
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- CN110739665A CN110739665A CN201910853021.0A CN201910853021A CN110739665A CN 110739665 A CN110739665 A CN 110739665A CN 201910853021 A CN201910853021 A CN 201910853021A CN 110739665 A CN110739665 A CN 110739665A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
- H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
- H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
- H02M3/325—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33507—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
- H02M3/33523—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention is suitable for the technical field of electronics, and discloses protection circuits and a switching power supply, wherein each protection circuit comprises a detection module, a short-circuit feedback module, a drive control module and a power switch module, the power switch module is connected with a primary winding of an external power module, an acquisition end of the detection module is connected with a secondary winding of the external power module, an output end of the detection module is connected with an input end of the short-circuit feedback module and used for detecting a voltage signal of the secondary winding of the external power module and outputting the voltage signal to the short-circuit feedback module, an output end of the short-circuit feedback module is connected with an input end of the drive control module and used for preprocessing the voltage signal and outputting the preprocessed voltage signal to the drive control module, and the drive control module is used for controlling the power switch module to be closed when the received voltage signal is lower than a preset voltage value.
Description
Technical Field
The invention belongs to the technical field of electronics, and particularly relates to protection circuits and a switching power supply.
Background
In the application of a switching power supply, when the output current of a secondary winding is overlarge or short circuit occurs, the output voltage of each secondary winding is reduced, the traditional voltage detection and maintenance method is that the output voltage is fed back to a main control chip after the change of the output voltage is detected, the duty ratio of the main control chip is increased to keep the stability of the output voltage, but the linkage damage of a fault system device is easily caused only by increasing the duty ratio, and the traditional method adopting a fuse further increases the size of the switching power supply, is high in cost and is inconvenient to maintain.
Disclosure of Invention
In view of this, the embodiment of the present invention provides protection circuits and a switching power supply, so as to solve the problems of easy damage to devices, high cost and inconvenient maintenance in the conventional fault detection and maintenance method for the switching power supply.
The th aspect of the embodiment of the invention provides a protection circuit, which comprises a detection module, a short circuit feedback module, a drive control module and a power switch module, wherein the power switch module is connected with a primary winding of an external power module;
the detection module is used for detecting a voltage signal of the secondary winding of the external power supply module and outputting the voltage signal to the short-circuit feedback module;
the output end of the short circuit feedback module is connected with the input end of the drive control module and used for outputting the voltage signal to the drive control module after being preprocessed;
and the output end of the driving control module is connected with the power switch module and is used for controlling the power switch module to be closed when the received voltage signal is lower than the th preset voltage value.
Optionally, after the driving control module controls the power switch module to be turned off, the primary winding of the external power module is powered off, and meanwhile, the detection module enters an initial state, and the driving control module provides an initial driving signal to turn on the power switch module.
Optionally, the detection module comprises an th resistor, a second resistor, a third resistor, a fourth resistor, a th capacitor, a th diode and an optical coupling isolation element;
the end of the th resistor and the end of the second resistor are connected with the acquisition end of the detection module, the second end of the th resistor is connected with the end of the th capacitor, the end of the third resistor and the anode of the th diode, and the second end of the second resistor is connected with the primary side input end of the optical coupling isolation element;
the second end of the capacitor is connected with the end of the fourth resistor, the second end of the third resistor and the anode of the diode are both grounded, and the second end of the fourth resistor is connected with the primary side output end of the optical coupling isolation element and the cathode of the diode;
and the secondary side input end of the optical coupling isolation element is connected with the output end of the detection module, and the secondary side output end of the optical coupling isolation element is grounded.
Optionally, the short circuit feedback module comprises: the circuit comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a second diode and a triode;
the th end of the fifth resistor is connected with the input end of the short-circuit feedback module, the second end of the fifth resistor is connected with the th end of the sixth resistor, the th end of the second capacitor and the anode of the second diode;
the cathode of the second diode is connected with the th end of the seventh resistor and the th end of the eighth resistor, the emitter of the triode is connected with the second end of the seventh resistor, the base of the triode is connected with the second end of the eighth resistor, and the collector of the triode is connected with the output end of the short circuit feedback module through the ninth resistor.
Optionally, the power switch module comprises: a switch tube and a tenth resistor;
the drain electrode of the switch tube is connected with the primary winding of the external power supply module, the grid electrode and the source electrode of the switch tube are both connected with the output end of the drive control module, and the source electrode of the switch tube is grounded through a tenth resistor.
Optionally, the driving control module comprises a control chip, a tenth resistor, a twelfth resistor, a thirteenth resistor, a third capacitor and a fourth capacitor;
the signal input pin of the control chip is connected with the input end of the drive control module, the signal input pin of the control chip is further connected with the source electrode of the switching tube through a tenth resistor, the signal input pin of the control chip is further grounded through a third capacitor, the signal output pin of the control chip is connected with the gate electrode of the switching tube through a twelfth resistor, the reference voltage pin of the control chip is connected with the end of a fourth capacitor through a thirteenth resistor, the clock pin of the control chip is connected with the end of the fourth capacitor, and the second end of the fourth capacitor is grounded.
Optionally, the protection circuit further comprises: a voltage feedback module;
the input end of the voltage feedback module is connected with the output end of the detection module, and the output end of the voltage feedback module is connected with the reference voltage pin and the common pin of the control chip and is used for acquiring a voltage signal at the output end of the detection module and sending the voltage signal to the drive control module;
the driving control module is further used for increasing the duty ratio of the power switch module when the received voltage signal is lower than a second preset voltage value, so that the secondary winding of the external power module outputs a preset voltage.
Optionally, the voltage feedback module comprises: a fourteenth resistance;
and the th end of the fourteenth resistor is connected with the output end of the detection module and the common pin of the control chip, and the second end of the fourteenth resistor is connected with the reference voltage pin of the control chip.
A second aspect of the embodiments of the present invention provides switching power supplies, including a voltage transformation module, further including any protection circuits provided in embodiment ;
the th end of the primary winding of the transformation module is connected with an external power grid, the second end of the primary winding is connected with a power switch module of the protection circuit, and the secondary winding of the transformation module is connected with a detection module of the protection circuit.
Optionally, the switching power supply further comprises: a third diode and a polarity capacitor;
the anode of the third diode is connected with the th end of the secondary winding of the voltage transformation module, and the cathode of the third diode is connected with the detection module of the protection circuit and the anode of the polar capacitor;
the negative pole of the polarity capacitor is connected with the second end of the secondary winding of the voltage transformation module, and the negative pole of the polarity capacitor is also grounded.
Compared with the prior art, the embodiment of the invention has the advantages that the detection module detects the voltage signal of the secondary winding of the external power supply module and outputs the voltage signal to the short-circuit feedback module, the short-circuit feedback module preprocesses the voltage signal and outputs the preprocessed voltage signal to the driving control module, and the driving control module controls the power supply switch module to be closed when the received voltage signal is lower than the preset voltage value, so that the automatic protection of overcurrent or short circuit of each output branch is realized, the problem of system damage caused by increasing the duty ratio is solved, devices are not damaged, the structure of the switching power supply is simplified, the cost is reduced, and the maintenance is more convenient.
Drawings
To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed for the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings according to these drawings without any creative effort.
Fig. 1 is a schematic structural diagram of a protection circuit according to an embodiment of the present invention;
FIG. 2 is a schematic circuit diagram of a detection module, a short circuit feedback module, and a voltage feedback module provided by an embodiment of the present invention;
fig. 3 is a circuit diagram of a driving control module, a power switch module and a transformer module according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In order to explain the technical means of the present invention, the following description will be given by way of specific examples.
Referring to fig. 1, the protection circuits provided in this embodiment may include a detection module 100, a short-circuit feedback module 200, a driving control module 300, and a power switch module 400, where the power switch module 400 is connected to a primary winding of an external power module, an acquisition end of the detection module 100 is connected to a secondary winding of the external power module, an output end of the detection module 100 is connected to an input end of the short-circuit feedback module 200, an output end of the short-circuit feedback module 200 is connected to an input end of the driving control module 300, and an output end of the driving control module 300 is connected to the power switch module 400.
Specifically, the detection module 100 detects a voltage signal of a secondary winding of the external power module and outputs the voltage signal to the short-circuit feedback module 200, the short-circuit feedback module 200 preprocesses the voltage signal and outputs the preprocessed voltage signal to the driving control module 300, and the driving control module 300 controls the power switch module 400 to be turned off when the received voltage signal is lower than the th preset voltage value, so that the external power module is in an intermittent working state, and the external power module is prevented from being damaged.
Referring to fig. 1, the transformer of the external power module may include a plurality of secondary windings, and the detection module 100 of the protection circuit of this embodiment may be connected to any secondary winding, for example, the detection module 100 may also be connected to Vo2 at the end of the second secondary winding, specifically, since the secondary windings of the transformer of the external power module are all wound on magnetic cores, when the output current of Vo1 or Vo2 is too large or short-circuited, the output voltage of each secondary winding may decrease, the detection module 100 detects the change of the output voltage and feeds a signal back to the short-circuit feedback module 200, the short-circuit feedback module 200 preprocesses the voltage signal and outputs the voltage signal to the driving control module 300, and the driving control module 300 controls the power switch module 400 to turn off when the received voltage signal is lower than a -th preset voltage value.
It can be known from the above description that the short circuit feedback module 200 is added in the protection circuit, the detection module 100 detects the voltage signal of the secondary winding of the external power supply module and outputs the voltage signal to the short circuit feedback module 200, the short circuit feedback module 200 preprocesses the voltage signal and outputs the voltage signal to the driving control module 300, the driving control module 300 controls the power switch module 400 to be turned off when the received voltage signal is lower than the th preset voltage value, thereby realizing the automatic protection of the overcurrent or short circuit of each output branch, solving the problem of system hazard brought by increasing the duty ratio, not damaging the device, simplifying the structure of the switching power supply, reducing the cost, and being more convenient for maintenance.
Alternatively, after the driving control module 300 controls the power switch module 400 to turn off, the primary winding of the external power module is powered off, and meanwhile, the detection module 100 enters an initial state, and the driving control module 300 provides an initial driving signal to turn on the power switch module 400.
After the primary winding of the external power module is powered off, the detection module 100 enters an initial state, that is, memory of the signal for the last times is cleared, then the driving control module 300 can provide an initial driving signal to turn on the power switch module 400, so that the primary winding of the external power module is powered on, and the protection circuit enters an initial working state again.
, referring to fig. 2, the detection module 100 of this embodiment may include a resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a 0 capacitor C1, a 1-th diode D1, and an optocoupler-isolation element IC1, where a terminal of the resistor R1 and a terminal of the second resistor R2 are both connected to the acquisition terminal of the detection module 100, a second terminal of the resistor R1 is connected to a terminal of the C1 of the capacitor C1, a terminal of the third resistor R3, and an anode of the D1 of the diode, and a second terminal of the second resistor R2 is connected to the primary side input terminal of the optocoupler-isolation element IC 1.
The second end of an th capacitor C1 is connected with the th end of a fourth resistor R4, the second end of the third resistor R3 and the anode of a th diode D1 are both grounded, the second end of the fourth resistor R4 is connected with the primary side output end of an optical coupling isolation element IC1 and the cathode of an th diode D1, the secondary side input end of the optical coupling isolation element IC1 is connected with the output end of the detection module 100, and the secondary side output end of the optical coupling isolation element IC1 is grounded.
resistor R1 and second resistor R2 obtain the voltage signal of the secondary winding of the external power module, and through the anti-interference of fourth resistor R4 and capacitor C1, the voltage signal that gets into the optical coupling isolation element IC1 does not interfere with the pulse, through the isolation of optical coupling isolation element IC1, make the voltage signal noise that detection module 100 outputs lower, the information is more accurate, and the circuit is simple, with low costs, do not need special detection chip.
Optionally, the short-circuit feedback module 200 of this embodiment may include a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a second capacitor C2, a second diode D2, and a transistor Q1, wherein the end of the fifth resistor R5 is connected to the input end of the short-circuit feedback module 200, the second end of the fifth resistor R5 is connected to the end of the sixth resistor R6, the end of the second capacitor C2, and the anode of the second diode D2, and the second end of the sixth resistor R6 and the second end of the second capacitor C2 are both grounded.
The cathode of the second diode D2 is connected to both the th end of the seventh resistor R7 and the th end of the eighth resistor R8, the emitter of the transistor Q1 is connected to the second end of the seventh resistor R7, the base of the transistor Q1 is connected to the second end of the eighth resistor R8, and the collector of the transistor Q1 is connected to the output end of the short-circuit feedback module 200 through the ninth resistor R9.
The sixth resistor R6 and the second capacitor C2 can filter the voltage signal output by the detection module 100, the eighth resistor R8 can reduce the static signal current of the triode Q1, prevent saturation distortion and increase input impedance, and the seventh resistor R7 can stabilize the working point of the triode Q1, so that the voltage signal input to the drive control module 300 is more accurate, and the circuit is rapidly powered off when no signal is input, thereby ensuring the safety of the circuit. The short circuit feedback module 200 has a simple circuit, does not need a special detection chip, and has low cost.
In addition, the existing power supply usually adds fuses to each branch circuit to realize overcurrent and short-circuit protection, but the protection is times, when the corresponding branch circuit has a fault, the corresponding fuses are disconnected, and the fuse power supply needs to be replaced again to restore to normal.
referring to fig. 3, the power switch module 400 of the present embodiment may include a switch Q2 and a tenth resistor R10, wherein the drain of the switch Q2 is connected to the primary winding of the external power module, the gate and the source of the switch Q2 are both connected to the output terminal of the driving control module 300, and the source of the switch Q2 is further grounded through the tenth resistor R10.
Optionally, the driving control module 300 of this embodiment may include a control chip IC2, a tenth resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a third capacitor C3, and a fourth capacitor C4, a signal input pin of the control chip IC2 is connected to the input terminal of the driving control module 300, a signal input pin of the control chip IC2 is further connected to the source of the switching tube Q2 through a tenth resistor R11, a signal input pin of the control chip IC2 is further grounded through a third capacitor C3, a signal output pin of the control chip IC2 is connected to the gate of the switching tube Q2 through a twelfth resistor R12, a reference voltage pin of the control chip IC2 is connected to the terminal of the fourth capacitor C4 through a thirteenth resistor R13, a clock pin of the control chip IC2 is connected to the fifth terminal of the fourth capacitor C87458, and a second terminal of the fourth capacitor C4 is grounded.
Optionally, referring to fig. 3, the protection circuit of this embodiment may further include: a voltage feedback module 500; the input terminal of the voltage feedback module 500 is connected to the output terminal of the detection module 100, and the output terminal of the voltage feedback module 500 is connected to the reference voltage pin and the common pin of the control chip IC 2.
Specifically, the voltage feedback module 500 obtains a voltage signal at the output end of the detection module 100 and sends the voltage signal to the driving control module 300, and when the received voltage signal is lower than a second preset voltage value, the driving control module 300 increases the duty ratio of the power switch module 400, so that the secondary winding of the external power module outputs a preset voltage, wherein the second preset voltage value is larger than the th preset voltage value, in practical application, under the normal working state of the external power module, the voltage feedback module 500 functions, and the short circuit feedback module 200 functions when an output short circuit or overcurrent fault occurs, that is, the driving control module 300 has priority control over the voltage feedback module 500 and the short circuit feedback module 200.
The voltage feedback module 500 of this embodiment may include a fourteenth resistor R14, wherein a th end of the fourteenth resistor R14 is connected to both the output terminal of the detection module 100 and the common pin of the control chip IC2, and a second end of the fourteenth resistor R14 is connected to the reference voltage pin of the control chip IC 2.
Optionally, the control chip IC2 of this embodiment may be a UCC28C44 chip, for example, the signal input pin Is of the UCC28C44 chip Is connected to the resistor R9 of the short-circuit feedback module 200, the signal input pin Is further connected to the source of the switching tube Q2 through the tenth resistor R11, the signal input pin Is further connected to the ground through the third capacitor C3, the signal output pin OUT of the UCC28C44 chip Is connected to the gate of the switching tube Q2 through the twelfth resistor R12, the reference voltage pin Vref of the UCC28C44 chip Is connected to the -th end of the fourth capacitor C4 through the thirteenth resistor R13, the clock pin of the UCC28C44 chip Is connected to the -th end of the fourth capacitor C4, the common pin COM of the UCC28C44 chip Is connected to the -th end of the fourteenth resistor R14, and the reference voltage pin Vref of the UCC28C44 chip Is connected to the second end of the fourteenth resistor R14.
In the above embodiment, the detection module 100 detects the voltage signal of the secondary winding of the external power supply module, and outputs the voltage signal to the short-circuit feedback module 200, the short-circuit feedback module 200 preprocesses the voltage signal and outputs the voltage signal to the driving control module 300, and the driving control module 300 controls the power switch module 400 to be turned off when the received voltage signal is lower than the th preset voltage value, so as to disconnect the primary winding of the external power supply module, thereby realizing automatic protection of overcurrent or short circuit of each output branch, solving the problem of system hazard caused by increasing duty ratio, not damaging devices, simplifying the structure of the switching power supply, reducing cost, and being more convenient to maintain.
Further , the present embodiment provides kinds of switching power supplies corresponding to the protection circuits in the above embodiments, and referring to fig. 3, the switching power supplies mainly include the transformer module 600 and any kinds of protection circuits described above.
The th end of the primary winding of the transformation module 600 is connected with an external power grid, the second end of the primary winding is connected with the power switch module 400 of the protection circuit, and the secondary winding of the transformation module 600 is connected with the detection module 100 of the protection circuit.
Optionally, the switching power supply of this embodiment may further include a third diode D3 and a polarity capacitor Cr1, an anode of the third diode D3 is connected to the th end of the secondary winding of the transformer module 600, a cathode of the third diode D3 is connected to the detection module 100 of the protection circuit and the anode of the polarity capacitor Cr1, a cathode of the polarity capacitor Cr1 is connected to the second end of the secondary winding of the transformer module 600, and a cathode of the polarity capacitor Cr1 is further grounded.
The switching power supply of the embodiment can further comprise a diode D4 and a polar capacitor Cr2, wherein the anode of the diode D4 is connected with the th end of the second secondary winding of the voltage transformation module 600, the cathode of the diode D4 is connected with the detection module 100 of the protection circuit and the anode of the polar capacitor Cr2, the cathode of the polar capacitor Cr2 is connected with the second end of the secondary winding of the voltage transformation module 600, and the cathode of the polar capacitor Cr2 is grounded.
In practical applications, the transformer module 600 may include a plurality of secondary windings, and the detection module 100 of the protection circuit of this embodiment may be connected to any secondary winding, for example, the detection module 100 may be further connected to the Vo2 end of the second secondary winding, specifically, since the secondary windings of the transformer module 600 are wound around the same magnetic cores, when the output current of Vo1 or Vo2 is too large or short-circuited, the output voltage of each secondary winding may decrease, the detection module 100 detects a change in the output voltage and feeds a signal back to the short-circuit feedback module 200, the short-circuit feedback module 200 pre-processes the voltage signal and outputs the voltage signal to the driving control module 300, when the voltage signal received by the driving control module 400 is lower than the preset voltage value, and after a fault is eliminated at Vo1 or Vo2, the driving control module 400 controls the power switch module 400 to open, and the transformer module 600 recovers to a normal operating state.
Above-mentioned switching power supply, protection circuit detect the voltage signal of the secondary winding of vary voltage module 600 to make the primary winding disconnection of vary voltage module 600 when the voltage signal that receives is less than predetermined voltage value, realized the automatic protection of each output branch's of vary voltage module 600 overcurrent or short circuit, solved the system harm problem that brings through the increase duty cycle, do not damage the device, simplified switching power supply structure, the cost is reduced, and it is more convenient to maintain.
It is obvious to those skilled in the art that, for convenience and simplicity of description, only the division of the above functional units and modules is illustrated, and in practical applications, the above functions may be distributed by different functional units and modules as needed, that is, the internal structure of the apparatus is divided into different functional units or modules to complete all or part of the above described functions.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
For example, the above-described system embodiments are merely illustrative, e.g., the modules or units may be divided into logical functional divisions, and other divisions may be made in practice, e.g., multiple units or components may be combined or integrated into another systems, or features may be omitted or not implemented, and other points, the shown or discussed couplings or direct couplings or communication connections between each other may be through interfaces, indirect couplings or communication connections of devices or units may be electrical, mechanical or other forms.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, that is, may be located in places, or may also be distributed on multiple network units.
In addition, the functional units in the embodiments of the present invention may be integrated into processing units, or each unit may exist alone physically, or two or more units are integrated into units.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.
Claims (10)
- The protection circuits are characterized by comprising a detection module, a short circuit feedback module, a drive control module and a power switch module, wherein the power switch module is connected with a primary winding of an external power module;the detection module is connected with the secondary winding of the external power supply module at the acquisition end, is connected with the input end of the short circuit feedback module at the output end, and is used for detecting a voltage signal of the secondary winding of the external power supply module and outputting the voltage signal to the short circuit feedback module;the output end of the short circuit feedback module is connected with the input end of the drive control module and is used for outputting the voltage signal to the drive control module after being preprocessed;and the output end of the drive control module is connected with the power switch module and is used for controlling the power switch module to be closed when the received voltage signal is lower than the th preset voltage value.
- 2. The protection circuit of claim 1, wherein after the driving control module controls the power switch module to turn off, the primary winding of the external power module is powered off, and simultaneously, the detection module enters an initial state, and the driving control module provides an initial driving signal to turn on the power switch module.
- 3. The protection circuit of claim 1, wherein the detection module comprises an th resistor, a second resistor, a third resistor, a fourth resistor, a th capacitor, a th diode and an optical coupling isolation element;the end of the th resistor and the end of the second resistor are connected with the acquisition end of the detection module, and the second end of the th resistor is connected with the end of the th capacitor, the end of the third resistor and the anode of the th diode;the second end of the capacitor is connected with the end of the fourth resistor, the second end of the third resistor and the anode of the diode are both grounded, and the second end of the fourth resistor is connected with the primary side output end of the optical coupling isolation element and the cathode of the diode;and the secondary side input end of the optical coupling isolation element is connected with the output end of the detection module, and the secondary side output end of the optical coupling isolation element is grounded.
- 4. The protection circuit of claim 1, wherein the short circuit feedback module comprises: the circuit comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a second diode and a triode;the th end of the fifth resistor is connected with the input end of the short-circuit feedback module, and the second end of the fifth resistor is connected with the th end of the sixth resistor, the th end of the second capacitor and the anode of the second diode;the cathode of the second diode is connected with the th end of the seventh resistor and the th end of the eighth resistor, the emitter of the triode is connected with the second end of the seventh resistor, the base of the triode is connected with the second end of the eighth resistor, and the collector of the triode is connected with the output end of the short circuit feedback module through the ninth resistor.
- 5. The protection circuit of any of claims 1-4, wherein the power switch module includes a switch tube and a tenth resistor;the drain electrode of the switch tube is connected with the primary winding of the external power supply module, the grid electrode and the source electrode of the switch tube are both connected with the output end of the driving control module, and the source electrode of the switch tube is grounded through the tenth resistor.
- 6. The protection circuit of claim 5, wherein the driving control module comprises a control chip, a tenth resistor, a twelfth resistor, a thirteenth resistor, a third capacitor and a fourth capacitor;the signal input pin of the control chip is connected with the input end of the drive control module, the signal input pin of the control chip is further connected with the source electrode of the switch tube through a tenth resistor, the signal input pin of the control chip is grounded through the third capacitor, the signal output pin of the control chip is connected with the gate electrode of the switch tube through the twelfth resistor, the reference voltage pin of the control chip is connected with the end of the fourth capacitor through the thirteenth resistor, the clock pin of the control chip is connected with the end of the fourth capacitor, and the second end of the fourth capacitor is grounded.
- 7. The protection circuit of claim 6, further comprising: a voltage feedback module;the input end of the voltage feedback module is connected with the output end of the detection module, and the output end of the voltage feedback module is connected with the reference voltage pin and the common pin of the control chip and is used for acquiring a voltage signal at the output end of the detection module and sending the voltage signal to the drive control module;the driving control module is further configured to increase a duty ratio of the power switch module when the received voltage signal is lower than a second preset voltage value, so that a secondary winding of the external power module outputs a preset voltage.
- 8. The protection circuit of claim 7, wherein the voltage feedback module comprises: a fourteenth resistance;an th end of the fourteenth resistor is connected with the output end of the detection module and the common pin of the control chip, and a second end of the fourteenth resistor is connected with the reference voltage pin of the control chip.
- 9, switching power supply, including transformation module, characterized by, also include the protection circuit of any of claims 1-8;the th end of the primary winding of the transformation module is connected with an external power grid, the second end of the primary winding is connected with the power switch module of the protection circuit, and the secondary winding of the transformation module is connected with the detection module of the protection circuit.
- 10. The switching power supply according to claim 9, further comprising: a third diode and a polarity capacitor;the anode of the third diode is connected with the th end of the secondary winding of the transformation module, and the cathode of the third diode is connected with the detection module of the protection circuit and the anode of the polar capacitor;and the negative electrode of the polar capacitor is connected with the second end of the secondary winding of the voltage transformation module, and the negative electrode of the polar capacitor is also grounded.
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| CN201910853021.0A CN110739665B (en) | 2019-09-10 | 2019-09-10 | Protection circuit and switching power supply |
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| CN201910853021.0A CN110739665B (en) | 2019-09-10 | 2019-09-10 | Protection circuit and switching power supply |
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| CN110739665B (en) | 2022-03-11 |
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