CN220570459U - Power supply surge protection circuit and switching power supply - Google Patents
Power supply surge protection circuit and switching power supply Download PDFInfo
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- CN220570459U CN220570459U CN202322197841.3U CN202322197841U CN220570459U CN 220570459 U CN220570459 U CN 220570459U CN 202322197841 U CN202322197841 U CN 202322197841U CN 220570459 U CN220570459 U CN 220570459U
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Abstract
The utility model relates to the technical field of electronics, in particular to a power supply surge protection circuit and a switching power supply, wherein the power supply surge protection circuit obtains divided voltage through a voltage division branch of a voltage division circuit, obtains reference voltage through a voltage stabilizer in a voltage stabilization branch, compares the reference voltage with the divided voltage through a comparator, can accurately detect the change of mains supply, when the mains supply exceeds a set voltage, the comparator outputs a low level, the switching circuit is turned off to cut off the power supply of a PWM controller, the circuit stops working, the power supply of a power supply device is cut off very rapidly and correctly, relevant equipment is protected, and when the mains supply is recovered to be normal, the comparator outputs a high level, the switching circuit is turned on to supply power for the PWM controller, the PWM controller outputs a control signal to control the conduction of a main power tube, and the power supply is recovered to work, so that intelligent detection conversion is realized, and the problem that the instantaneous energy applied to the input end of the switching power supply is excessively large to damage the main power tube is solved.
Description
Technical Field
The utility model relates to the technical field of electronics, in particular to a power supply surge protection circuit and a switching power supply.
Background
The switching power supply is a high-frequency electric energy conversion device, when the input end is instantaneously provided with large energy input, namely, when an input surge exists, the generated surge energy enables the energy on a main power tube in a main power stage circuit in the switching power supply to be larger than the maximum energy which can be born by the main power tube, so that the main power tube is damaged, and even other devices are damaged.
In order to avoid the above problem, the conventional surge protection scheme employs a varistor to absorb surge energy, where the capability of the varistor to absorb the surge energy is in positive correlation with the leakage current flowing through the varistor, but the leakage current flowing through the varistor is larger only when the input voltage added with the surge energy is large, and when the input voltage of the surge energy is large but insufficient to make the leakage current of the varistor large, the capability of the varistor to absorb the surge energy is insufficient, and the main power tube may be damaged due to the excessive energy. Therefore, the piezoresistor is used for absorbing surge energy, and the reliable protection of the main power tube cannot be realized although the circuit structure is simple.
Disclosure of Invention
The embodiment of the utility model provides a power supply surge protection circuit and a switching power supply, which are used for solving the problem that the main power tube is damaged due to overlarge energy applied to the main power tube caused by overlarge instantaneous energy at the input end of the switching power supply.
In a first aspect, the utility model provides a power supply surge protection circuit, which comprises a voltage division circuit (12), a comparison circuit (13), a PWM controller (14) and a main power tube (15), wherein the input end of the voltage division circuit (12) is used for inputting a power supply signal, the output end of the voltage division circuit (12) is connected with the input end of the comparison circuit (13), the output end of the comparison circuit (13) is electrically connected with the power supply end of the PWM controller (14), the power supply end of the PWM controller (14) is connected with the control end of the main power tube (15), the input end of the main power tube (15) is used for inputting a power supply signal, and the output end of the main power tube (15) is connected with a load (16);
wherein the voltage dividing circuit (12) includes: the input end of the voltage dividing branch is used for inputting the power supply signal, and the output end of the voltage dividing branch is connected with the comparison input end of the comparison circuit (13) so as to output a divided comparison voltage; the voltage stabilizing branch is connected with a voltage stabilizer in series, and the output end of the voltage stabilizer is connected with the reference input end of the comparison circuit (13) so as to output reference voltage;
the comparison circuit (13) is used for comparing the comparison voltage of the voltage division circuit (12) with a reference voltage and outputting a comparison signal; the PWM controller (14) is used for outputting a control signal of the main power tube (15) according to the comparison signal, and controlling the on and off of the main power tube (15).
In one embodiment, the power supply surge protection circuit further comprises:
the input end of the switching circuit is electrically connected with the output end of the comparison circuit (13), the output end of the switching circuit is connected with the power supply end of the PWM controller (14), and the switching circuit is used for realizing the on-off of the power supply end of the PWM controller (14) according to the comparison signal output by the comparison circuit (13).
In one embodiment, the switching circuit includes: the control end of the first switching tube is connected with the output end of the comparison circuit (13), the input end of the first switching tube is connected with the control end of the second switching tube, the output end of the first switching tube is grounded, the input end of the second switching tube is connected with a first power supply, the output end of the second switching tube is connected with the power supply end of the PWM controller (14), one end of the first resistor is connected with the control end of the second switching tube, and the other end of the first resistor is connected with the first power supply.
In an embodiment, an input protection circuit, an input end of the input protection circuit is connected with a mains supply, and an output end of the input protection circuit is used for outputting a protection power supply signal;
the input protection circuit includes: fuse, piezo-resistor, safety capacitor, second resistance, third resistance, inductor, the positive pole of commercial power is connected to the input of fuse, the output of fuse is connected the input of piezo-resistor, the negative pole of commercial power is connected to the output of piezo-resistor, safety capacitor with the piezo-resistor is parallelly connected, the one end of second resistance is connected the output of fuse, the other end of second resistance passes through the negative pole of commercial power is connected to the third resistance, the first input of inductor is connected the output of fuse, the negative pole of commercial power is connected to the second input of inductor, the first output and the second output of inductor are used for outputting protection power signal.
In one embodiment, the power supply surge protection circuit further comprises:
the input end of the bridge rectifier circuit is connected with the output end of the input protection circuit, and the output end of the bridge rectifier circuit is used for outputting a rectified power signal;
the bridge rectifier circuit includes: the first bridge arm branch is provided with a first rectifying diode and a third rectifying diode, the second bridge arm branch is provided with a second rectifying diode and a fourth rectifying diode, the input end of the first bridge arm branch is connected with the first output end of the inductance coil, the input end of the second bridge arm branch is connected with the second output end of the inductance coil, and the output ends of the first bridge arm branch and the second bridge arm branch are used for outputting rectifying power signals.
In one embodiment, the power supply surge protection circuit further comprises:
the input end of the filter circuit is electrically connected with the output end of the bridge rectifier circuit, and the output end of the filter circuit is connected with the input end of the voltage divider circuit (12);
the filter circuit includes: the filter comprises a first filter capacitor, a second filter capacitor, a first filter inductor and a second filter inductor, wherein the cathode of the second filter capacitor is connected with the positive electrode end of the first filter capacitor, the positive electrode end of the first filter capacitor is connected with one end of the first filter inductor, the negative electrode end of the first filter capacitor is connected with the positive electrode of the fourth filter diode, the other end of the first filter inductor is connected with the positive electrode end of the second filter capacitor, the positive electrode end of the second filter capacitor is connected with the input end of the voltage dividing circuit (12), the negative electrode of the second filter capacitor is grounded, one end of the second filter inductor is connected with the positive electrode of the fourth filter diode, and the other end of the second filter inductor is grounded.
In one embodiment, the comparison circuit (13) comprises: the positive input end of the comparator is connected with the output end of the voltage stabilizer, the negative input end of the comparator is connected with the output end of the voltage dividing branch, and the output end of the comparator is electrically connected with the input end of the switching circuit.
In one embodiment, the voltage dividing branch includes: the circuit comprises a first voltage dividing resistor, a second voltage dividing resistor and a first capacitor, wherein a power signal is input into one end of the first voltage dividing resistor, the other end of the first voltage dividing resistor and one end of the second voltage dividing resistor are connected with the input end of a comparison circuit (13), the other end of the second voltage dividing resistor is grounded, the input end of the comparison circuit (13) is connected with one end of the first capacitor, and the other end of the first capacitor is grounded.
The second aspect. The present utility model provides a switching power supply comprising a main power stage circuit comprising a power supply surge protection circuit as described in the first aspect and improvements thereto.
In one embodiment, the main power stage circuit further comprises:
the power supply comprises a first inductor, a first diode and a second capacitor, wherein one end of the first inductor is connected with the negative electrode of the first diode respectively at the output end of a main power tube (15), the other end of the first inductor is connected with the positive electrode end of the second capacitor respectively to be connected with a load, the positive electrode of the first diode is grounded, and the negative electrode of the second capacitor is grounded.
Compared with the prior art, the embodiment of the utility model has the beneficial effects that:
the power supply surge protection circuit disclosed by the utility model divides a power supply signal through the voltage division branch of the voltage division circuit to obtain a voltage division voltage, the voltage stabilizer in the voltage division branch is used for stabilizing the power supply signal to obtain a reference voltage, the reference voltage is compared with the voltage division voltage through the comparator, the change of the mains supply can be accurately detected, when the mains supply exceeds a set voltage, the comparator outputs a low level, the switching circuit is turned off, the power supply of the PWM controller is cut off, the circuit stops working, the power supply of a power supply device is cut off very rapidly and accurately, relevant equipment is protected, when the mains supply is recovered to be normal, the comparator outputs a high level, the switching circuit is turned on to supply power for the PWM controller, the PWM controller outputs a control signal to control the conduction of the main power tube, and the power supply is recovered to work, so that the intelligent detection conversion is realized, and the problem that the instantaneous energy at the input end of the switching power supply is overlarge, and the main power tube is damaged is solved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the description of the embodiments of the present utility model will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic block diagram of a first power surge protection circuit according to an embodiment of the present utility model;
fig. 2 is a schematic block diagram of a second power surge protection circuit according to an embodiment of the present utility model;
FIG. 3 is a schematic diagram of circuit connection of a switching circuit according to an embodiment of the present utility model;
fig. 4 is a schematic block diagram of a third power surge protection circuit according to an embodiment of the present utility model;
FIG. 5 is a schematic diagram of a circuit connection of an input protection circuit according to an embodiment of the present utility model;
fig. 6 is a schematic block diagram of a fourth power surge protection circuit according to an embodiment of the present utility model;
FIG. 7 is a schematic diagram illustrating a circuit connection of a bridge rectifier circuit according to an embodiment of the present utility model;
FIG. 8 is a schematic block diagram of a fifth power surge protection circuit according to an embodiment of the present utility model;
FIG. 9 is a schematic diagram of a circuit connection of a filter circuit according to an embodiment of the present utility model;
FIG. 10 is a schematic diagram of circuit connection of a voltage dividing branch circuit according to an embodiment of the present utility model;
FIG. 11 is a schematic diagram of the circuit connections of a main power stage circuit according to an embodiment of the present utility model;
the device comprises 12 parts of voltage dividing circuit, 13 parts of comparison circuit, 14 parts of PWM controller, 15 parts of main power tube, 16 parts of load, 17 parts of switch circuit, 18 parts of input protection circuit, 19 parts of bridge rectifier circuit, 20 parts of filter circuit.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects solved by the utility model more clear, the utility model is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.
In the description of the present utility model, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships that are based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present utility model and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.
In the following description, for the purpose of providing a thorough understanding of the present utility model, detailed structures and steps are presented in order to illustrate the technical solution presented by the present utility model. Preferred embodiments of the present utility model are described in detail below, however, the present utility model may have other embodiments in addition to these detailed descriptions.
Unless defined otherwise, 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 disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
In an embodiment, as shown in fig. 1, a schematic block diagram of a power surge protection circuit is provided, which includes a voltage division circuit 12, a comparison circuit 13, a PWM controller 14, and a main power tube 15, wherein an input end of the voltage division circuit 12 is used for inputting a power signal, an output end of the voltage division circuit 12 is connected to an input end of the comparison circuit 13, an output end of the comparison circuit 13 is electrically connected to a power supply end of the PWM controller 14, a power supply end of the PWM controller 14 is connected to a control end of the main power tube 15, an input end of the main power tube 15 is used for inputting a power signal, and an output end of the main power tube 15 is connected to a load 16;
wherein the voltage dividing circuit 12 includes: the input end of the voltage dividing branch is used for inputting the power supply signal, and the output end of the voltage dividing branch is connected with the comparison input end of the comparison circuit 13 so as to output the divided comparison voltage; the voltage stabilizing branch is connected with a voltage stabilizer in series, and the output end of the voltage stabilizer is connected with the reference input end of the comparison circuit 13 so as to output reference voltage;
the comparison circuit 13 is used for comparing the comparison voltage of the voltage division circuit 12 with a reference voltage and outputting a comparison signal; the PWM controller 14 is configured to output a control signal of the main power tube 15 according to the comparison signal, and control on/off of the main power tube 15.
The working process of the power supply surge protection circuit is as follows:
the power supply signal is input to the voltage dividing circuit 12, a first voltage dividing branch of the voltage dividing circuit 12 divides the power supply signal and outputs a divided comparison voltage, a second voltage dividing branch of the voltage dividing circuit 12 stabilizes the power supply signal through a voltage stabilizer to generate a high-precision fixed voltage source, the reference voltage is provided for the comparison circuit 13, the comparison circuit 13 is used for comparing the reference voltage with the comparison voltage, when the power supply signal is normal, the comparison voltage is smaller than the reference voltage, the comparison circuit 13 outputs a conducting signal, the PWM controller 14 works normally and outputs a control square wave, the main power tube 15 is normally conducted and provides voltage for a later-stage circuit; when the power supply signal is abnormal, the comparison voltage is larger than the reference voltage, the comparison circuit 13 outputs a turn-off signal, the power supply of the PWM controller 14 is cut off, and the circuit stops working.
According to the power supply surge protection circuit, the voltage of the power supply signal is stabilized through the voltage stabilizer, the first voltage division branch circuit in the voltage division circuit divides the voltage of the power supply signal, the comparison circuit 13 compares and isolates, the PWM controller 14 controls and isolates, the main power tube 15 can be prevented from being damaged, and the main power tube 15 and the rear-stage components are reliably protected.
In the circuit, when the power supply signal is recovered to be normal, the output end of the comparison circuit 13 outputs the conduction signal, the circuit is recovered to be normal, the power supply surge protection circuit has simple structure and lower cost, the normal operation of the switching power supply is not influenced, the main power tube in the switching power supply is protected, and the safety of the switching power supply is ensured.
In an embodiment, as shown in fig. 2, a schematic block diagram of a power surge protection circuit is provided, and based on the protection circuit shown in fig. 1, the power surge protection circuit further includes a switch circuit 17, an input end of the switch circuit 17 is electrically connected to an output end of the comparison circuit 13, an output end of the switch circuit 17 is connected to a power supply end of the PWM controller 14, and the switch circuit 17 is configured to implement on-off of the power supply end of the PWM controller 14 according to a comparison signal output by the comparison circuit 13.
The working process of the power supply surge protection circuit is as follows:
the switching circuit 17 realizes the on-off of the power supply end of the PWM controller 14 according to the comparison signal output by the comparison circuit 13, when the comparison circuit 13 outputs the on-signal, the switching circuit 17 is conducted to input the power supply voltage to the power supply end of the PWM controller 14, the PWM controller 14 normally works to output a control square wave, the main power tube 15 is normally conducted to provide voltage for the subsequent circuit; when the comparison circuit 13 outputs a turn-off signal, the switching circuit 17 is turned off, the power supply of the PWM controller 14 is cut off, and the circuit stops working.
In the power supply surge protection circuit of this embodiment, the switch circuit 17 may include a first-stage control circuit and a second-stage control circuit, where the comparison circuit 13 outputs a conducting signal to the first-stage control circuit of the switch circuit 17, so that the first-stage control circuit is conducted, the second-stage control circuit is conducted by the output signal after the first-stage control circuit is conducted, and the second-stage control circuit outputs a power supply signal to the PWM controller 14 after the second-stage control circuit is conducted, so that the control of the circuit is realized through the second-stage conduction of the switch circuit 17, and the stability and reliability of the circuit are well ensured.
As another embodiment, the switch circuit 17 may further include only a single-stage control circuit, the comparison circuit 13 outputs a conducting signal to the single-stage control circuit of the switch circuit 17, so that the single-stage control circuit is conducted, the single-stage control circuit outputs a power supply signal to the PWM controller 14 after being conducted, and the switch circuit 17 is conducted to realize the control of the circuit, so that the stability and reliability of the circuit are ensured, and meanwhile, the cost is reduced.
In an embodiment, as shown in fig. 3, a schematic circuit connection diagram of a switching circuit is provided, on the basis of the switching circuit shown in fig. 2, the switching circuit 17 includes a first switching tube Q1, a second switching tube Q2, and a first resistor R8, a control end of the first switching tube Q1 is connected to an output end of the comparison circuit 13, an input end of the first switching tube Q1 is connected to a control end of the second switching tube Q2, an output end of the first switching tube Q1 is grounded, an input end of the second switching tube Q2 is connected to a first power supply, an output end of the second switching tube Q2 is connected to a power supply end of the PWM controller 14, one end of the first resistor R8 is connected to a control end of the second switching tube Q2, and the other end of the first resistor R8 is connected to the first power supply.
The working process of the power supply surge protection circuit is as follows:
the comparison circuit 13 outputs a conducting signal, the conducting signal is larger than the conducting voltage of the first switching tube Q1, the conducting voltage enables the first switching tube Q1 to be conducted, after the first switching tube Q1 is conducted, the voltage of a first power supply connected with the input end of the first switching tube Q1 flows to the output end of the first switching tube Q1, the voltage of the control end of the second switching tube Q2 is reduced, the second switching tube Q2 is conducted, the first power supply flows to the power supply end of the PWM controller 14 through the second switching tube Q2, the power supply end of the PWM controller 14 is provided with the power supply signal, and the PWM controller 14 starts to work.
In the power supply surge protection circuit of the embodiment, the first resistor R8 in the switch circuit 17 is a bias resistor of the second switch tube Q2, and is used for providing a bias voltage for the second switch tube Q2, protecting the second switch tube Q2, preventing the second switch tube Q2 from breakdown, and the switch circuit 17 can realize control over the PWM controller 14 by sequentially triggering and conducting the two switch tubes, so as to improve the reliability of the circuit.
In this embodiment, two switching transistors are illustrated as transistors, and it is understood that the switching transistor of the present utility model may be any switching transistor, for example, a transistor, a MOS transistor, a field effect transistor, or the like.
In an embodiment, as shown in fig. 4, a schematic block diagram of a power surge protection circuit is provided, and the power surge protection circuit further includes an input protection circuit 18 based on the protection circuit shown in fig. 1, where an input end of the input protection circuit 18 is connected to a mains supply, and an output end of the input protection circuit 18 is used for outputting a protection power signal.
In the power surge protection circuit of the present embodiment, in the input protection circuit 18, the commercial power flows through the input protection circuit 18 and then flows to the voltage dividing circuit 12, so that the voltage dividing circuit 12 can be protected.
In one embodiment, as shown in fig. 5, a schematic circuit connection diagram of an input protection circuit is provided, and the input protection circuit 18 includes: fuse F1, piezo-resistor MOV1, safety capacitor CX1, second resistance R1, third resistance R2, inductor L1, the positive pole end of commercial power is connected to fuse F1's input, piezo-resistor MOV 1's input is connected to fuse F1's output, the negative pole end of commercial power is connected to piezo-resistor MOV 1's output, safety capacitor CX1 is parallelly connected with piezo-resistor MOV1, fuse F1's output is connected to second resistance R1's one end, fuse F1's negative pole end is connected through third resistance R2 to second resistance R1's the other end, inductor L1's first input is connected to fuse F1's output, inductor L1's second input is connected the negative pole end of commercial power, inductor L1's first output and second output are used for outputting protection power signal.
The working process of the power supply surge protection circuit is as follows:
the voltage of the mains supply 220V flows to the piezoresistor MOV1, the filter capacitor CX1, the second resistor R1 and the inductance coil L1 through the fuse F1, the piezoresistor MOV1 and the filter capacitor CX1 are connected with the mains supply 220V in parallel, the second resistor R1 is connected with the third resistor R2 in series, the whole of the second resistor R1 and the third resistor R2 after the series is connected with the mains supply 220V in parallel, the inductance coil L1 is connected with the mains supply 220V in parallel, specifically, the first input end of the inductance coil L1 is connected with the positive end of the mains supply, the second input end of the inductance coil L1 is connected with the negative end of the mains supply, and the mains supply 220V is filtered by the filter capacitor CX1 and the inductance coil L1 to form a protection power supply signal.
According to the power supply surge protection circuit, the piezoresistor MOV1, the second resistor R1 and the third resistor R2 have overvoltage protection, partial surge energy can be absorbed, the filter capacitor CX1 and the inductance coil L1 filter the mains supply 220V, the effect of smoothing signals is achieved, and the back-stage circuit can be well protected.
In an embodiment, as shown in fig. 6, a schematic block diagram of a power surge protection circuit is provided, and on the basis of the protection circuit shown in fig. 4, the power surge protection circuit further includes a bridge rectifier circuit 19, an input end of the bridge rectifier circuit 19 is connected to an output end of the input protection circuit 18, and an output end of the bridge rectifier circuit 19 is used for outputting a rectified power signal.
In the power surge protection circuit of the embodiment, the mains supply is rectified by the bridge rectifier circuit 19 after passing through the input protection circuit 18, so that the power can be used and controlled more effectively.
In one embodiment, as shown in fig. 7, a schematic circuit connection diagram of a bridge rectifier circuit is provided, and the bridge rectifier circuit 19 shown in fig. 6 includes: the first bridge arm branch is provided with a first rectifying diode D5 and a third rectifying diode D8, the second bridge arm branch is provided with a second rectifying diode D7 and a fourth rectifying diode D9, the input end of the first bridge arm branch is connected with the first output end of the inductance coil L1, the input end of the second bridge arm branch is connected with the second output end of the inductance coil L1, and the output ends of the first bridge arm branch and the second bridge arm branch are used for outputting rectifying power signals.
Specifically, the positive electrode of the first rectifying diode D5 is connected to the first output end of the inductor L1, the positive electrode of the second rectifying diode D7 is connected to the second output end of the inductor L1, the positive electrode of the third rectifying diode D8 is grounded, the negative electrode of the third rectifying diode D8 is connected to the positive electrode of the first rectifying diode D5, the positive electrode of the fourth rectifying diode D9 is grounded, the negative electrode of the fourth rectifying diode D9 is connected to the positive electrode of the second rectifying diode D7, and the negative electrode of the first rectifying diode D5 is connected to the negative electrode of the second rectifying diode D7 for outputting a rectified power signal.
The working process of the power supply surge protection circuit is as follows:
when the protection power supply signal passes through a positive half shaft, positive voltage is applied to the first rectifying diode D5 and the second rectifying diode D7, the first rectifying diode D5 and the second rectifying diode D7 are conducted, reverse voltage is applied to the third rectifying diode D8 and the fourth rectifying diode D9, the third rectifying diode D8 and the fourth rectifying diode D9 are cut off, a pass circuit is formed between the first rectifying diode D5 and the second rectifying diode D7 in the bridge rectifying circuit 19 and the input end and the ground of the voltage dividing circuit 12, positive half-wave rectifying voltage is formed at the input end of the voltage dividing circuit 12, positive half-wave rectifying voltage is applied to the third rectifying diode D8 and the fourth rectifying diode D9 when the filter voltage is at the negative half shaft, the third rectifying diode D8 and the fourth rectifying diode D9 are conducted, reverse voltage is applied to the first rectifying diode D5 and the second rectifying diode D7, the first rectifying diode D5 and the second rectifying diode D7 are cut off, and a pass circuit is formed between the third rectifying diode D8 and the fourth rectifying diode D9 in the bridge rectifying circuit 19 and the input end of the voltage dividing circuit 12, and the pass circuit forms a full-wave rectifying voltage at the input end of the voltage at the voltage dividing circuit 12.
In the power surge protection circuit of the present embodiment, the bridge rectifier circuit 19 rectifies the filtered voltage to convert ac into smoother dc to form a rectified power signal.
In an embodiment, as shown in fig. 8, a schematic block diagram of a power surge protection circuit is provided, and on the basis of the protection circuit shown in fig. 6, the power surge protection circuit further includes a filter circuit 20, an input end of the filter circuit 20 is electrically connected to an output end of the bridge rectifier circuit 19, and an output end of the filter circuit 20 is connected to an input end of the voltage divider circuit 12.
In the power surge protection circuit of the embodiment, the rectified power signal is filtered by the filter circuit 20, so that the stability of the output voltage can be ensured.
In one embodiment, as shown in fig. 9, a schematic circuit connection diagram of a filter circuit is provided, and the filter circuit 20 includes, on the basis of the filter circuit 20 shown in fig. 8: the filter capacitor comprises a first filter capacitor CE1, a second filter capacitor CE2, a first filter inductor L2 and a second filter inductor L3, wherein the negative electrode of a second rectifier diode D5 is connected with the positive electrode of the first filter capacitor CE1, the positive electrode of the first filter capacitor CE1 is connected with one end of the first filter inductor L2, the negative electrode of the first filter capacitor CE1 is connected with the positive electrode of a fourth rectifier diode D9, the other end of the first filter inductor L2 is connected with the positive electrode of the second filter capacitor CE2, the positive electrode of the second filter capacitor CE2 is connected with the input end of a voltage dividing circuit 12, the negative electrode of the second filter capacitor CE2 is grounded, one end of the second filter inductor L3 is connected with the positive electrode of the fourth rectifier diode D9, and the other end of the second filter inductor L3 is grounded.
The working process of the power supply surge protection circuit is as follows:
the rectified power signal is filtered by the first filter capacitor CE1, a part of the ac component is filtered, the voltage filtered by the first filter capacitor CE1 flows to the second filter capacitor CE2 through the first filter inductor L2, the second filter capacitor CE2 further filters the ac component, and the filtered voltage is input to the voltage divider circuit 12.
In the power surge protection circuit of this embodiment, the filter circuit 20 can filter out unnecessary ac components, improve the quality of voltage, and protect the post-stage circuit.
In an embodiment, the comparing circuit 13 is a comparator, a positive input end of the comparator is connected to an output end of the voltage stabilizer, a negative input end of the comparator is connected to an output end of the voltage dividing branch, and an output end of the comparator is connected to an input end of the switching circuit 17.
The power surge protection circuit of the embodiment can accurately capture the comparison voltage and the reference voltage, compare the comparison voltage with the reference voltage, and if the comparison voltage is smaller than the reference voltage, the comparator outputs a high level to the switch circuit 17 to control the switch circuit 17 to be conducted and input a power supply signal to the power supply end of the PWM controller 14; if the comparison voltage is greater than the reference voltage, the comparator outputs a low level to the switching circuit 17, the switching circuit 17 is turned off, the power supply of the PWM controller 14 is cut off, and the circuit stops working.
As other embodiments, the comparison circuit 13 may be an optical coupler or an operational amplifier, so that the isolation effect of the optical coupler is better, and the operational amplifier can save cost.
In one embodiment, as shown in fig. 10, a schematic circuit connection diagram of a voltage dividing branch circuit is provided, where the voltage dividing branch circuit includes: the power supply signal is input to one end of the first voltage dividing resistor R5, the second voltage dividing resistor R6 and the first capacitor C1, the other end of the first voltage dividing resistor R5 and one end of the second voltage dividing resistor R6 are connected with the input end of the comparison circuit 13, the other end of the second voltage dividing resistor R6 is grounded, the input end of the comparison circuit 13 is connected with one end of the first capacitor C1, and the other end of the first capacitor C1 is grounded.
The working process of the power supply surge protection circuit is as follows:
the power signal flows into the first voltage dividing resistor R5, then flows into the second voltage dividing resistor R6, is divided by the first voltage dividing resistor R5 and the second voltage dividing resistor R6, is filtered by the first capacitor C1, and flows into the comparison circuit 13.
According to the power supply surge protection circuit, the voltage dividing branch circuit is connected in series by the first voltage dividing resistor R5 and the second voltage dividing resistor R6 to divide voltage, the voltage dividing proportion can be adjusted according to actual conditions, the structure is simple, and the cost is lower.
In one embodiment, a switching power supply is provided that includes a main power stage circuit that includes a power supply surge protection circuit as described in any of the embodiments above. The switching power supply well protects the main power tube, and ensures the safety of the switching power supply.
In one embodiment, as shown in fig. 11, a schematic circuit connection diagram of a main power stage circuit is provided, and the main power stage circuit further includes:
the power supply circuit comprises a first inductor L4, a first diode D2 and a second capacitor CE3, wherein one end of the first inductor L4 is connected with the negative electrode of the first diode D2 at the output end of a main power tube 15 respectively, the other end of the first inductor L4 is connected with the positive electrode end of the second capacitor CE3 to be loaded respectively, the positive electrode of the first diode D2 is grounded, and the negative electrode of the second capacitor CE3 is grounded.
The working process of the main power stage circuit is as follows:
the power supply signal flows to the first diode D2 after the main power tube is conducted, the first diode D2 flows to the first inductor L4 after voltage stabilization, and the first inductor L4 and the second capacitor CE3 flow to the load after filtering.
In the main power stage circuit of this embodiment, the first diode D2 performs voltage stabilization, so as to protect the post-stage circuit, and the first inductor L4 and the second capacitor CE3 perform filtering and anti-interference effects.
The above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model 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 scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present utility model, and are intended to be included in the scope of the present utility model.
Claims (10)
1. A power supply surge protection circuit, comprising:
the power supply circuit comprises a voltage dividing circuit (12), a comparison circuit (13), a PWM controller (14) and a main power tube (15), wherein the input end of the voltage dividing circuit (12) is used for inputting a power supply signal, the output end of the voltage dividing circuit (12) is connected with the input end of the comparison circuit (13), the output end of the comparison circuit (13) is electrically connected with the power supply end of the PWM controller (14), the power supply end of the PWM controller (14) is connected with the control end of the main power tube (15), the input end of the main power tube (15) is used for inputting the power supply signal, and the output end of the main power tube (15) is connected with a load (16);
wherein the voltage dividing circuit (12) includes: the input end of the voltage dividing branch is used for inputting the power supply signal, and the output end of the voltage dividing branch is connected with the comparison input end of the comparison circuit (13) so as to output a divided comparison voltage; the voltage stabilizing branch is connected with a voltage stabilizer in series, and the output end of the voltage stabilizer is connected with the reference input end of the comparison circuit (13) so as to output reference voltage;
the comparison circuit (13) is used for comparing the comparison voltage of the voltage division circuit (12) with a reference voltage and outputting a comparison signal; the PWM controller (14) is used for outputting a control signal of the main power tube (15) according to the comparison signal, and controlling the on and off of the main power tube (15).
2. The power supply surge protection circuit of claim 1, wherein the power supply surge protection circuit further comprises:
the input end of the switching circuit is electrically connected with the output end of the comparison circuit (13), the output end of the switching circuit is connected with the power supply end of the PWM controller (14), and the switching circuit is used for realizing the on-off of the power supply end of the PWM controller (14) according to the comparison signal output by the comparison circuit (13).
3. The power surge protection circuit of claim 2 wherein,
the switching circuit includes: the control end of the first switching tube is connected with the output end of the comparison circuit (13), the input end of the first switching tube is connected with the control end of the second switching tube, the output end of the first switching tube is grounded, the input end of the second switching tube is connected with a first power supply, the output end of the second switching tube is connected with the power supply end of the PWM controller (14), one end of the first resistor is connected with the control end of the second switching tube, and the other end of the first resistor is connected with the first power supply.
4. The power supply surge protection circuit of claim 1, wherein the power supply surge protection circuit further comprises:
the input end of the input protection circuit is connected with the mains supply, and the output end of the input protection circuit is used for outputting a protection power supply signal;
the input protection circuit includes: fuse, piezo-resistor, safety capacitor, second resistance, third resistance, inductor, the positive pole of commercial power is connected to the input of fuse, the output of fuse is connected the input of piezo-resistor, the negative pole of commercial power is connected to the output of piezo-resistor, safety capacitor with the piezo-resistor is parallelly connected, the one end of second resistance is connected the output of fuse, the other end of second resistance passes through the negative pole of commercial power is connected to the third resistance, the first input of inductor is connected the output of fuse, the negative pole of commercial power is connected to the second input of inductor, the first output and the second output of inductor are used for outputting protection power signal.
5. The power supply surge protection circuit of claim 4, wherein the power supply surge protection circuit further comprises:
the input end of the bridge rectifier circuit is connected with the output end of the input protection circuit, and the output end of the bridge rectifier circuit is used for outputting a rectified power signal;
the bridge rectifier circuit includes: the first bridge arm branch is provided with a first rectifying diode and a third rectifying diode, the second bridge arm branch is provided with a second rectifying diode and a fourth rectifying diode, the input end of the first bridge arm branch is connected with the first output end of the inductance coil, the input end of the second bridge arm branch is connected with the second output end of the inductance coil, and the output ends of the first bridge arm branch and the second bridge arm branch are used for outputting rectifying power signals.
6. The power supply surge protection circuit of claim 5, wherein the power supply surge protection circuit further comprises:
the input end of the filter circuit is electrically connected with the output end of the bridge rectifier circuit, and the output end of the filter circuit is connected with the input end of the voltage divider circuit (12);
the filter circuit includes: the filter comprises a first filter capacitor, a second filter capacitor, a first filter inductor and a second filter inductor, wherein the cathode of the second filter capacitor is connected with the positive electrode end of the first filter capacitor, the positive electrode end of the first filter capacitor is connected with one end of the first filter inductor, the negative electrode end of the first filter capacitor is connected with the positive electrode of the fourth filter diode, the other end of the first filter inductor is connected with the positive electrode end of the second filter capacitor, the positive electrode end of the second filter capacitor is connected with the input end of the voltage dividing circuit (12), the negative electrode of the second filter capacitor is grounded, one end of the second filter inductor is connected with the positive electrode of the fourth filter diode, and the other end of the second filter inductor is grounded.
7. The power surge protection circuit of claim 2 wherein,
the comparison circuit (13) includes: the positive input end of the comparator is connected with the output end of the voltage stabilizer, the negative input end of the comparator is connected with the output end of the voltage dividing branch, and the output end of the comparator is electrically connected with the input end of the switching circuit.
8. The power surge protection circuit of claim 1, wherein,
the voltage dividing branch circuit includes: the circuit comprises a first voltage dividing resistor, a second voltage dividing resistor and a first capacitor, wherein a power signal is input into one end of the first voltage dividing resistor, the other end of the first voltage dividing resistor and one end of the second voltage dividing resistor are connected with the input end of a comparison circuit (13), the other end of the second voltage dividing resistor is grounded, the input end of the comparison circuit (13) is connected with one end of the first capacitor, and the other end of the first capacitor is grounded.
9. A switching power supply, comprising:
a main power stage circuit comprising a power supply surge protection circuit according to any one of claims 1-8.
10. The switching power supply of claim 9 wherein said main power stage circuit further comprises:
the power supply comprises a first inductor, a first diode and a second capacitor, wherein one end of the first inductor is connected with the negative electrode of the first diode respectively at the output end of a main power tube (15), the other end of the first inductor is connected with the positive electrode end of the second capacitor respectively to be connected with a load, the positive electrode of the first diode is grounded, and the negative electrode of the second capacitor is grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322197841.3U CN220570459U (en) | 2023-08-15 | 2023-08-15 | Power supply surge protection circuit and switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322197841.3U CN220570459U (en) | 2023-08-15 | 2023-08-15 | Power supply surge protection circuit and switching power supply |
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| Publication Number | Publication Date |
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| CN220570459U true CN220570459U (en) | 2024-03-08 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202322197841.3U Active CN220570459U (en) | 2023-08-15 | 2023-08-15 | Power supply surge protection circuit and switching power supply |
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| Country | Link |
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| CN (1) | CN220570459U (en) |
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- 2023-08-15 CN CN202322197841.3U patent/CN220570459U/en active Active
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