CN109818328B - Overvoltage protection circuit of switching power supply - Google Patents
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Abstract
The invention discloses a switch power supply overvoltage protection circuit which mainly comprises a power supply circuit, a voltage acquisition module and a voltage processing module. The acquisition end of the voltage acquisition module is connected to the input end of an inductor in the power circuit and is used for acquiring the voltage at the front end of the inductor, and the normal operation, abnormal short circuit and other conditions of the power circuit can be displayed in the voltage waveform at the front end of the inductor, so that the overvoltage short circuit condition in the power circuit can be accurately detected by acquiring the voltage value at the front end of the inductor; meanwhile, the feedback point of voltage is added at the front end of the inductor, because the current does not pass through the inductor and the capacitor, the time delay of voltage brought by the inductor and the capacitor can be eliminated, the response speed of overvoltage protection is improved, the voltage processing module and the voltage acquisition module are matched to detect abnormal voltage waveforms, the control signal of the controller is adjusted according to the detection result, the accurate and quick detection of the overvoltage of the power circuit can be realized, and the overvoltage loss of the power circuit is reduced.
Description
Technical Field
The invention relates to the technical field of server mainboards, in particular to a switch power supply overvoltage protection circuit.
Background
The server motherboard has a high requirement for stability, where the stability of the power supply is the basis for the motherboard stability. Fig. 1 is a circuit diagram of a power supply circuit, in which a switching power supply implements switching control by driving two switching tubes (such as a mos fet) to be alternately turned on, and in practice, due to the structure of the mos fet, the possibility of short circuit is high, and may occur in actual production.
At present, the difference between the input voltage and the output voltage of the server motherboard switching power supply is usually large, for example, 12V is used as input, and the output is about 1.05V, 1V, 0.95V, etc., wherein, after the MosFET is powered up after short circuit, the power supply module is destructive, if 12V is directly connected to the load, the power supply module is also destructive for the chip, for example, 12V is far beyond the withstand voltage value of the chip with the rated 1V, so that the possibility of short circuit and burning is greatly increased; and the switching power supply of the server mainboard usually needs to supply power to low-voltage chips such as a CPU, a PCH and an HD expansion chip, and the load chips are not expensive and are easily damaged, so that the cost is greatly increased.
The stability of the switching power supply can be improved by increasing the voltage of the protection circuit. The protection circuit for increasing the voltage can not only protect the power module, but also protect the next-level load chip, and is a common protection method for the switching power supply at present.
In a conventional voltage protection circuit, when the output voltage is abnormally increased and is higher than a preset upper limit value due to the detection of a fault of a switching power supply, the switching power supply is controlled to be turned off so as to realize protection. The method can realize overvoltage protection, but the time delay can still cause great damage to the circuit because the point of detecting the voltage is at the output end and the response speed is slow.
Therefore, how to improve the response speed of the overvoltage protection is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to provide an overvoltage protection circuit of a switching power supply, which can realize accurate and rapid detection of overvoltage of the power supply circuit and reduce overvoltage loss of the power supply circuit.
In order to solve the above technical problem, the present invention provides an overvoltage protection circuit for a switching power supply, including: the device comprises a power circuit, a voltage acquisition module and a voltage processing module;
the acquisition end of the voltage acquisition module is connected to the input end of an inductor in the power circuit and used for acquiring the front end voltage of the inductor and outputting a first signal when the front end voltage is a normal square wave; when the front end voltage is an abnormal short circuit high level waveform, outputting a second signal;
the output end of the voltage acquisition module is connected to the input end of the voltage processing module, the voltage processing module is used for carrying out signal identification processing on the received signal, and when the received signal is the first signal, a normal working control signal is output; when the received signal is the second signal, outputting a short circuit cut-off signal;
the output end of the voltage processing module is connected to the control end of the controller, and the controller is used for controlling the working state of a switch tube in the power circuit according to the signal output by the voltage processing module.
Optionally, the voltage acquisition module includes: a first resistor and a second resistor;
the first end of the second resistor is connected to the input end of an inductor in the power circuit, the second end of the second resistor and the first end of the first resistor are connected to the first end of the voltage processing module, and the second end of the first resistor is grounded;
correspondingly, the first signal is a square wave signal with a normal duty ratio, and the second signal is an abnormal high level signal.
Optionally, the voltage processing module is specifically: an analog-to-digital converter and an abnormal signal judger;
the input end of the analog-to-digital converter is connected to the second end of the second resistor, and the output end of the analog-to-digital converter is connected to the input end of the abnormal signal judger and used for converting the received digital signal into an analog signal and outputting the analog signal;
the output end of the abnormal signal judger is connected with the control end of the controller and is used for judging the abnormality of the received signal.
Alternatively, the abnormality signal determiner is embodied as a signal determiner constituting the controller.
Optionally, the voltage acquisition module further includes: a third resistor, a diode and a capacitor;
the first end of the third resistor is connected to the first end of the second resistor, the second end of the third resistor is connected to the first end of the diode, the second end of the diode and the first end of the capacitor are connected to the first end of the voltage processing module, and the second end of the capacitor is connected to the second end of the first resistor;
correspondingly, the first signal is a periodic charge-discharge waveform, the second signal is a charge waveform with a voltage value positively correlated to a charge time, and the voltage processing module is configured to compare the received voltage with a preset reference voltage and output a normal operation control signal when the received voltage is not higher than the preset reference voltage; and outputting a short circuit cut-off signal when the received voltage is higher than the preset reference voltage.
Optionally, the voltage processing module specifically includes: a voltage comparator.
Optionally, the diode is a key diode.
Optionally, the capacitor is a mica capacitor.
Optionally, the input terminal of the voltage processing module is further connected to the voltage output terminal of the power circuit.
Optionally, the second end of the first resistor is connected to a source ground terminal of a lower MOS transistor in the power supply circuit.
The overvoltage protection circuit of the switching power supply mainly comprises a power supply circuit, a voltage acquisition module and a voltage processing module. The acquisition end of the voltage acquisition module is connected to the input end of an inductor in the power circuit and is used for acquiring the front end voltage of the inductor, and the normal operation, abnormal short circuit and other conditions of the power circuit can be displayed in the voltage waveform of the front end of the inductor; meanwhile, the feedback point of voltage is added at the front end of the inductor, because the current does not pass through the inductor and the capacitor, the time delay of voltage brought by the inductor and the capacitor can be eliminated, the response speed of overvoltage protection is improved, the voltage processing module and the voltage acquisition module are matched to detect abnormal voltage waveforms, the control signal of the controller is adjusted according to the detection result, the accurate and quick detection of the overvoltage of the power circuit can be realized, and the overvoltage loss of the power circuit is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a circuit diagram of a power circuit;
FIG. 2 is a schematic diagram of a conventional overvoltage protection circuit;
fig. 3 is a circuit diagram of an overvoltage protection circuit of a switching power supply according to an embodiment of the invention;
fig. 4 is a circuit diagram of another over-voltage protection switching power supply circuit according to an embodiment of the present invention;
fig. 5 is a circuit diagram of another over-voltage protection switching power supply circuit according to an embodiment of the present invention.
Detailed Description
The core of the invention is to provide the overvoltage protection circuit of the switching power supply, which can realize accurate and rapid detection of overvoltage of the power supply circuit and reduce overvoltage loss of the power supply circuit.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a circuit diagram of a power supply circuit commonly used at present, in which main functional components include a controller, a switching tube, an inductor and a capacitor, it should be noted that the power supply circuit may further include other auxiliary functional devices, fig. 1 is only one of the circuit forms, and of course, a switching power supply circuit having the same switching principle (i.e., controlled by the switching tube and including the inductor and/or the capacitor) as that of the circuit diagram shown in fig. 1 is also applicable to the overvoltage protection switching power supply circuit provided by the present invention, and only the switching power supply circuit provided by the present invention uses the same principle of switching (i.e., controlled by the switching tube and including the inductor and/or the capacitor
The power circuit shown in fig. 1 is described as an example, and other power circuit forms can be referred to the description of the present invention, and are not described herein again.
At present, a switching power supply generally needs to output a part with an overvoltage protection function, and the overvoltage protection function is to control the switching power supply to be turned off so as to realize protection when the output voltage is abnormally increased and is higher than an upper limit value set in advance due to the fact that the switching power supply is detected to be in a fault state.
Fig. 2 is a schematic diagram of a conventional overvoltage protection circuit, which detects a terminal voltage of an output capacitor of a power supply, and is connected to a comparator integrated inside a switching power supply chip through a voltage feedback line to compare the terminal voltage with a preset reference voltage. The output of the comparator is connected to the enable end of the main control of the switching power supply chip. When the feedback voltage is higher than the reference voltage, the output of the comparator is turned over, the output is changed from high to low, so that the controller is closed, and the protection is realized.
The method can realize overvoltage protection, but because the point of detecting the voltage is at the output end of the power supply, if an upper switching tube (such as an upper mosfet) is short-circuited, voltage feedback is carried out on an output capacitor by considering the path of energy transfer (from input to inductance to output capacitor), and basically at the tail end of the whole energy transfer, and the response of the inductance, the capacitance and a controller has time delay, so that the response speed is slow, and the protection response cannot be carried out on the condition that the upper mosfet is short-circuited for the first time.
The invention provides a switch power supply overvoltage protection circuit, which adds a voltage feedback point at the input end of an inductor, thereby eliminating the voltage delay brought by the inductor and a capacitor, avoiding the response delay of a controller and improving the response speed of overvoltage protection.
The first embodiment is as follows:
fig. 3 is a circuit diagram of an overvoltage protection circuit of a switching power supply according to an embodiment of the present application. The circuit mainly comprises: power supply circuit, voltage acquisition module and voltage processing module.
The power circuit in the overvoltage protection circuit of the switching power supply takes the circuit structure shown in fig. 1 as an example, the acquisition end of the voltage acquisition module is connected to the input end of an inductor in the power circuit, and due to the alternate conduction of the upper and lower MOSFETs of the switching power supply, the voltage waveform at the input end of the inductor is a square wave with a certain duty ratio (the duty ratio is determined by the ratio of the output voltage to the input voltage and is usually less than 50%), the high level of the square wave is the input voltage, and the low level of the square wave is 0V.
The voltage acquisition module is used for acquiring the front end voltage of the inductor and outputting a first signal when the front end voltage is a normal square wave; and when the front end voltage is an abnormal short circuit high level waveform, outputting a second signal. The first signal and the second signal respectively refer to a normal inductance front-end voltage waveform and an abnormal inductance front-end voltage waveform (in this embodiment, an abnormal short circuit of a switching tube), and may be an original front-end voltage waveform signal directly acquired or a waveform signal after processing an original voltage, which is not limited herein. When the switch tube is short-circuited in the power circuit, the waveform of the front end of the inductor can be changed, after voltage acquisition is carried out through the voltage acquisition module, abnormity in the circuit can be reflected in the voltage waveform output by the voltage acquisition module, the voltage waveform output by the voltage acquisition module is abnormal, and subsequent abnormal judgment of the power circuit can be carried out based on the waveform.
In this embodiment, the voltage acquisition module is disposed at the front end of the inductor, and increases a voltage feedback point at the input end of the inductor to acquire the voltage at the front end of the inductor and the front end of the capacitor, so that the delay of the voltage brought by the inductor and the capacitor can be eliminated, and especially, the response speed of overvoltage protection can be increased under the condition of short circuit of the upper switching tube.
The specific circuit form of the voltage acquisition module is not limited herein, and the voltage acquisition module can acquire the voltage at the front end of the inductor, for example, the voltage acquisition module can be directly arranged on a connecting wire at the front end of the inductor and provided with a protection resistor, or provided with a capacitor and other devices for voltage acquisition.
The output end of the voltage acquisition module is connected with the input end of the voltage processing module. The voltage processing module is used for carrying out signal identification processing on the received signal and outputting a normal working control signal when the received signal is a first signal; and when the received signal is the second signal, outputting a short circuit cut-off signal.
The output end of the voltage processing module is connected to the control end of the controller, the controller of the current power supply circuit needs to receive analog signals to perform normal processing, therefore, the voltage processing module needs to perform abnormity judgment on the acquired voltage, judge whether the power supply circuit has abnormal conditions such as short circuit and the like, and finally generate analog signals to be input to the control end of the controller. Specifically, the voltage processing module may be in the form of an AD converter and a voltage determination circuit, or a voltage comparator, and the like, and may implement the above function.
And the controller in the power supply circuit is used for controlling the working state of the switching tube in the power supply circuit according to the signal output by the voltage processing module. The control process of the switch tube by the specific controller can refer to the related description of the existing switch tube circuit, and is not described in detail herein.
Based on the technical scheme, the overvoltage protection circuit of the switching power supply provided by the embodiment of the invention mainly comprises a power supply circuit, a voltage acquisition module and a voltage processing module. The acquisition end of the voltage acquisition module is connected to the input end of an inductor in the power circuit and is used for acquiring the front end voltage of the inductor, and the normal operation, abnormal short circuit and other conditions of the power circuit can be displayed in the voltage waveform of the front end of the inductor; meanwhile, the feedback point of voltage is added at the front end of the inductor, because the current does not pass through the inductor and the capacitor, the time delay of voltage brought by the inductor and the capacitor can be eliminated, the response speed of overvoltage protection is improved, the voltage processing module and the voltage acquisition module are matched to detect abnormal voltage waveforms, the control signal of the controller is adjusted according to the detection result, the accurate and quick detection of the overvoltage of the power circuit can be realized, and the overvoltage loss of the power circuit is reduced.
Example two:
the specific circuit form of the voltage acquisition module in the above embodiment is not limited, and the voltage acquisition module in this embodiment includes: the first resistor and the second resistor are described as an example.
The first end of the second resistor is connected to the input end of the inductor in the power supply circuit, the second end of the second resistor and the first end of the first resistor are connected to the first end of the voltage processing module, and the second end of the first resistor is grounded.
The first resistor and the second resistor mainly play a role in voltage division of current, voltage at the front end of the inductor is reduced and then detected, and overvoltage influence on a subsequent voltage processing module is avoided.
When the voltage acquisition module is a first resistor and a second resistor, the normal voltage signal at the front end of the inductor is a square wave signal with a normal duty ratio, and correspondingly, the first signal is also a square wave signal with a normal duty ratio; when the power circuit is short-circuited, the front end of the inductor is a continuous high level signal, so that the second signal is an abnormal high level signal correspondingly.
The voltage processing module is matched with the voltage acquisition module, and when the voltage acquisition module is a first resistor and a second resistor, the voltage processing module is used for distinguishing a square wave signal with a normal duty ratio and an abnormal high-level signal, generating an identification result and converting the identification result into an analog quantity to be input into the controller. Specifically, the voltage processing module may specifically select an analog-to-digital converter and an abnormal signal judger, or may also select a voltage comparator to perform analog-to-digital conversion and then determine the abnormal model through a controller, which is not limited herein.
It should be noted that in this embodiment, the resistance values of the first resistor and the second resistor need to be determined according to parameters of other components in the circuit, and the specific calculation method may refer to related technologies, which is not described herein again.
Since the adc and the abnormal signal determiner are used as the voltage processing module to perform the fast screening determination without changing the original power circuit, the adc and the abnormal signal determiner are used as an example for description herein. Specifically, the input end of the analog-to-digital converter is connected to the second end of the second resistor, and the output end of the analog-to-digital converter is connected to the input end of the abnormal signal judger, and is used for converting the received digital signal into an analog signal and outputting the analog signal; the output end of the abnormal signal judger is connected with the control end of the controller and is used for judging the abnormality of the received signal.
In order to reduce components in the circuit and reduce the cost, it is preferable that the controller in the original power supply circuit is used as the signal determiner. Specifically, a code corresponding to the signal type determination may be input to the controller, so that the controller has a corresponding signal processing function (this section may refer to the implementation method of the related art).
Example three:
in the second embodiment, the voltage acquisition module directly acquires the voltage at the front end of the inductor, and in order to reduce a time delay caused by performing analog or digital judgment on a subsequent signal and avoid a response delay of the controller, preferably, the voltage acquisition module may further include: a third resistor, a diode and a capacitor,
fig. 4 is a circuit diagram of the overvoltage protection switching power supply circuit provided in this embodiment, and a circuit structure of the voltage acquisition module is shown by a dashed line frame in fig. 4.
The voltage acquisition module in the circuit comprises current-limiting resistors R1, R2, R3(R2> R1> > R3), a reverse cut-off diode D1 and a voltage detection capacitor C1, the voltage processing module is a voltage comparator with a preset reference voltage input in the positive direction, and the terminal voltage of C1 is connected to the negative input end of the comparator as a voltage feedback line.
The first end of a second resistor (R2) in the voltage acquisition module is connected to the input end of an inductor in the power supply circuit, the second end of the second resistor and the first end of a first resistor (R1) are connected to the positive input end of the voltage processing module (comparator), and the second end of the first resistor is grounded.
The first end of the third resistor (R3) is connected to the first end of the second resistor (R2), the second end of the third resistor (R3) is connected to the first end of the diode (D1), the second end of the diode and the first end of the capacitor (C1) are connected to the first end of the voltage processing module, and the second end of the capacitor is connected to the second end of the first resistor.
When the power supply circuit is in a normal state, the point A is at a high level. The D1 path is cut off in the reverse direction, the high level charges the C1 capacitor through the voltage division of R1 and R2, and the voltage of the C1 capacitor rises (normally, the comparator is not triggered); when the point a is low, R2 and R1 are much larger than R3, and D1 is forward biased to conduct, so C1 discharges through D1 and R3, and the next cycle starts. Accordingly, the first signal is a periodic charge-discharge waveform. The above circuit ensures that the charge and discharge of the C1 capacitor reach balance in one period.
The voltage processing module compares the received voltage with a preset reference voltage, and outputs a normal operation control signal (for example, output 1) when the received voltage is not higher than the preset reference voltage.
The switching power supply works in an abnormal normal state (such as a mosfet short circuit), so that the voltage at the point a is continuously maintained at a high level (approximately equal to the input voltage), C1 is continuously charged, accordingly, the second signal is a charging waveform with a voltage value positively correlated to the charging time, the voltage processing module compares the received voltage with a preset reference voltage, the voltage of C1 exceeds the reference voltage of the comparator along with the extension of the charging time, the comparator outputs a short circuit cut-off signal (such as output 0), and the circuit form is relatively earlier than a protection point on the output capacitor and has a faster response speed. The response time is determined by the time constant of R3 and C1.
In the overvoltage protection switching power supply circuit provided by this embodiment, when the power supply circuit operates in an abnormal normal state (a mosfet short circuit occurs), the voltage at the point a is continuously maintained at a high level (equal to the input voltage), and accordingly, the second signal is a charging waveform whose voltage value is positively correlated with the charging time for the continuous charging of C1, and finally, the voltage of C1 will exceed the reference voltage of the comparator for protection, and the response time is determined by the time constant of R3 and C1. Compared with the protection on an output capacitor, the protection point is more forward, the response speed is faster, and the quick OVP protection can be realized only by adding part of circuits in the circuit of the current switching power supply, so that the device is simple to realize and has low cost.
It should be noted that, in this embodiment, the size of the capacitance value needs to ensure the normal operation of each component in the circuit. In particular, Vref: the reference voltage is set to a reference voltage,
C1capacitor charging voltage, Vin: power supply input voltage, fsw: the frequency of the switching of the power supply,
diode D1Pressure drop, Vout: the power supply outputs voltage, and each resistance-capacitance value needs to meet the following conditions:
the voltage comparator can realize the comparison between the test voltage value and the preset standard voltage value while realizing the analog-to-digital conversion of the voltage, and preferably, the voltage processing module can specifically select the voltage comparator.
In order to improve the response speed, the diode can be a key diode, and the capacitor can be a mica capacitor.
In addition, in this embodiment, the second end of the first resistor needs to be grounded, and in order to reduce the arrangement of the ground terminal, preferably, the second end of the first resistor may be connected to a source ground terminal of a lower MOS transistor in the power supply circuit.
Example four:
in order to implement dual monitoring of the power circuit, improve detection efficiency, and avoid the influence of accidental faults in a single inspection mode on the abnormal judgment, preferably, on the basis of the third embodiment, the input end of the voltage processing module may be further connected to the voltage output end of the power circuit, as shown in fig. 5, the circuit diagram of the overvoltage protection switching power circuit provided in this embodiment is shown, on the basis of fig. 4, only one wire is added, and if a device in the front-end voltage acquisition module fails, the acquisition of the output-end voltage and the comparison judgment with a preset reference voltage value may also implement abnormal monitoring of the power circuit, thereby completing dual protection of the power circuit, the implementation is simple, the detection effect is improved without increasing additional device cost.
Of course, the lead wire in the present embodiment may not be provided, and is not limited herein.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (8)
1. An overvoltage protection switching power supply circuit, comprising: the device comprises a power circuit, a voltage acquisition module and a voltage processing module;
the acquisition end of the voltage acquisition module is connected to the input end of an inductor in the power circuit and used for acquiring the front end voltage of the inductor and outputting a first signal when the front end voltage is a normal square wave; when the front end voltage is an abnormal short circuit high level waveform, outputting a second signal;
the output end of the voltage acquisition module is connected to the input end of the voltage processing module, the voltage processing module is used for carrying out signal identification processing on the received signal, and when the received signal is the first signal, a normal working control signal is output; when the received signal is the second signal, outputting a short circuit cut-off signal;
the output end of the voltage processing module is connected to the control end of the controller, and the controller is used for controlling the working state of a switching tube in the power circuit according to the signal output by the voltage processing module;
the voltage acquisition module includes: the circuit comprises a first resistor, a second resistor, a third resistor, a diode and a capacitor; the first end of the second resistor is connected to the input end of an inductor in the power circuit, the second end of the second resistor and the first end of the first resistor are connected to the first end of the voltage processing module, and the second end of the first resistor is grounded; the first end of the third resistor is connected to the first end of the second resistor, the second end of the third resistor is connected to the first end of the diode, the second end of the diode and the first end of the capacitor are connected to the first end of the voltage processing module, and the second end of the capacitor is connected to the second end of the first resistor; correspondingly, the first signal is a periodic charge-discharge waveform, the second signal is a charge waveform with a voltage value positively correlated to a charge time, and the voltage processing module is configured to compare the received voltage with a preset reference voltage and output a normal operation control signal when the received voltage is not higher than the preset reference voltage; and outputting a short circuit cut-off signal when the received voltage is higher than the preset reference voltage.
2. The overvoltage protection switching power supply circuit of claim 1, wherein the voltage processing module is specifically: an analog-to-digital converter and an abnormal signal judger;
the input end of the analog-to-digital converter is connected to the second end of the second resistor, and the output end of the analog-to-digital converter is connected to the input end of the abnormal signal judger and used for converting the received digital signal into an analog signal and outputting the analog signal;
the output end of the abnormal signal judger is connected with the control end of the controller and is used for judging the abnormality of the received signal.
3. The over-voltage protection switching power supply circuit according to claim 2, wherein the abnormality signal determiner is a signal determiner constituting the controller.
4. The overvoltage protection switching power supply circuit according to claim 1, wherein the voltage processing module is specifically: a voltage comparator.
5. The overvoltage protection switching power supply circuit according to claim 1, wherein said diode is a key diode.
6. The overvoltage protection switching power supply circuit according to claim 1, wherein said capacitor is a mica capacitor.
7. The overvoltage protection switching power supply circuit of any one of claims 1 or 4 to 6, wherein the input of said voltage handling module is further connected to a voltage output of said power supply circuit.
8. The over-voltage protection switching power supply circuit according to claim 1, wherein a second terminal of the first resistor is connected to a source ground terminal of a lower MOS transistor in the power supply circuit.
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