CN116742943A

CN116742943A - Switching power supply and control method thereof

Info

Publication number: CN116742943A
Application number: CN202311018052.7A
Authority: CN
Inventors: 郑凌波; 林新春
Original assignee: Lii Semiconductor Inc
Current assignee: Lii Semiconductor Inc
Priority date: 2023-08-14
Filing date: 2023-08-14
Publication date: 2023-09-12
Anticipated expiration: 2043-08-14
Also published as: CN116742943B

Abstract

The application relates to the technical field of power supplies, and discloses a switching power supply and a control method thereof, wherein the switching power supply provides stable output voltage for a load, and the switching power supply comprises: the device comprises a detection module, a main controller and a switch module; the detection module is connected with the load feedback FB, the detection module is connected with the switch module, the switch module is connected with the load, and the main controller is respectively connected with the detection module and the switch module; the detection module is used for detecting loop current of the load, sending a closing signal to the main controller based on the loop current, and sending an opening signal to the main controller after a first preset time period; the main controller is used for forwarding the received closing signal and opening signal to the switch module, counting the opening signal, and stopping forwarding the opening signal to the switch module when the number of times of confirming the opening signal is larger than the preset number of times; the switch module is used for receiving the on signal to be on and receiving the off signal to be off. Thus, the damage of the internal circuit and the loaded device caused by the switching power supply is solved.

Description

Switching power supply and control method thereof

Technical Field

The application relates to the technical field of power supplies, in particular to a switching power supply and a control method thereof.

Background

The wide application of large-scale integrated circuits makes electronic devices develop toward miniaturization and solid-state, and at the same time, higher requirements are put on power supply devices.

In the prior art, when a circuit is started or the current is high, the switch power supply is in delay protection, namely, when the circuit is started or the current is high, the power supply is turned off, after a period of delay protection, the circuit is turned on again, whether the current of a load is overloaded or not is detected, if the circuit is still in an overload state, the delay protection state is re-entered, and if the current of the load is continuously in the overload state, the circuit is turned on repeatedly when the current is high, so that the internal circuit of the switch power supply and devices of the load are easy to damage.

In summary, the conventional switching power supply easily causes damage to the internal circuits of the switching power supply and the devices of the load.

Disclosure of Invention

The application mainly aims to provide a switching power supply and a control method thereof, and aims to solve the technical problem that the existing switching power supply is easy to cause damage to internal circuits of the switching power supply and devices of loads.

To achieve the above object, the present application provides a switching power supply that supplies a stable output voltage to a load, comprising: the device comprises a detection module, a main controller and a switch module;

the detection module is connected with the load feedback FB, the detection module is connected with the switch module, the switch module is connected with the load, and the main controller is respectively connected with the detection module and the switch module;

the detection module is used for detecting loop current of the load, sending a closing signal to the main controller based on the loop current, and sending an opening signal to the main controller after a first preset time period;

the main controller is used for forwarding the received closing signal and the received opening signal to the switch module, counting the opening signal, stopping forwarding the opening signal to the switch module and resetting the count when the number of times of confirming the opening signal is larger than the preset number of times;

the switch module is used for receiving the on signal to be on and receiving the off signal to be off.

Optionally, the main controller is further configured to forward the start signal to the switch module after a second preset period of time from the time when the count is cleared.

Optionally, the main controller includes: a counting unit and a forwarding unit;

the first end of the forwarding unit is connected with the detection module, the second end of the forwarding unit is connected with the switch module, and the counting unit is connected with the forwarding unit;

the forwarding unit is used for receiving the opening signal and the closing signal sent by the detection module and forwarding the opening signal and the closing signal to the switch module;

the counting unit is used for counting the starting signals received by the forwarding unit, and sending a cut-off signal to the forwarding unit and resetting the count when the number of times of the starting signals is confirmed to be larger than the preset number of times;

the forwarding unit is further configured to receive the cut-off signal and stop forwarding the start signal to the switch module;

the counting unit is further used for sending a recovery signal to the forwarding unit after the second preset time period from the counting zero clearing time;

the forwarding unit is further configured to receive the recovery signal, and recover forwarding the start signal to the switch module.

Optionally, the forwarding unit includes: a pulse width control unit;

the pulse width control unit is used for converting the received opening signal and closing signal into corresponding pulse width opening signal and pulse width closing signal, then sending the corresponding pulse width opening signal and pulse width closing signal to the switch module, stopping forwarding the opening signal to the switch module when the closing signal is received, and forwarding the opening signal to the switch module when the restoring signal is received.

Optionally, the detection module includes: the device comprises a detection unit and a delay unit;

the detection unit is connected between the load feedback FB and the switch module, and the delay units are respectively connected with the detection unit and the forwarding unit.

Optionally, the detection unit includes: the acquisition resistor and the first operation comparator;

the collection resistor is connected between the load feedback FB and the switch module, the non-inverting input end of the first operation comparator is connected with the connection end of the collection resistor and the switch module, the inverting input end of the first operation comparator is connected with a first preset reference voltage, and the output end of the first operation comparator is connected with the delay unit.

Optionally, the delay unit includes: the triode, the second resistor, the capacitor and the second operation comparator;

the output end of the first operation comparator is connected with the base electrode of the triode, the emitter electrode of the triode is connected with the inverting input end of the second operation comparator, the non-inverting input end of the second operation comparator is connected with a second preset reference voltage, and the output end of the second operation comparator is connected with the forwarding unit;

the second resistor is connected with the capacitor in parallel, a first end of the second resistor connected with the capacitor is connected with an inverting input end of the second operation comparator, and a second end of the second resistor connected with the capacitor is grounded.

Optionally, the switch module includes: a switching tube;

the switching tube is connected in series in a primary coil of the transformer, and the delay unit is connected between the main controller and the switching tube.

In order to achieve the above object, the present application further provides a control method of a switching power supply, where the control method of a switching power supply is applied to a main controller of the switching power supply as described above, and the control method of the switching power supply includes:

receiving an opening signal sent by the detection module, and counting the opening signal;

and confirming whether the number of times of the starting signal is larger than the preset number of times, if so, stopping forwarding the starting signal to the switch module and resetting the count.

Optionally, the main controller includes: the control method of the switching power supply comprises the following steps:

controlling the counting unit to count the starting signals, and confirming whether the times of the starting signals are larger than the preset times, if yes, sending a cut-off signal to the forwarding unit, and resetting the count;

and controlling the forwarding unit to receive the cut-off signal and stopping forwarding the starting signal to the switch module.

The application provides a switching power supply and a control method thereof, wherein the switching power supply provides stable output voltage for a load, and the switching power supply comprises: the device comprises a detection module, a main controller and a switch module; the detection module is connected with the load feedback FB, the detection module is connected with the switch module, the switch module is connected with the load, and the main controller is respectively connected with the detection module and the switch module; the detection module is used for detecting loop current of the load, sending a closing signal to the main controller based on the loop current, and sending an opening signal to the main controller after a first preset time period; the main controller is used for forwarding the received closing signal and the received opening signal to the switch module, counting the opening signal, stopping forwarding the opening signal to the switch module and resetting the count when the number of times of confirming the opening signal is larger than the preset number of times; the switch module is used for receiving the on signal to be on and receiving the off signal to be off. The application realizes that the main controller forwards the closing signal sent by the detection module to the switch module, after counting the opening signal sent by the detection module, if the number of times of the opening signal is larger than the preset number of times, the opening signal is stopped to be forwarded to the switch module, thereby preventing the overload current from being repeatedly conducted to the load when the loop current of the load is always in an overload state, and preventing the switch power supply from being repeatedly switched between the off state and the on state, and further protecting the internal circuit of the switch power supply and the devices of the load.

Drawings

FIG. 1 is a logic block diagram of one embodiment of a switching power supply of the present application;

FIG. 2 is a schematic diagram illustrating connection of a main controller of an embodiment of a switching power supply according to the present application;

FIG. 3 is a schematic diagram illustrating connection of a detection module according to an embodiment of the present application;

FIG. 4 is a schematic diagram illustrating connection of a detection unit according to an embodiment of the present application;

FIG. 5 is a schematic diagram illustrating connection of delay units according to an embodiment of the present application;

fig. 6 is a schematic flow chart of a switching module of an embodiment of the switching power supply of the present application.

Reference numerals illustrate:

the achievement of the objects, functional features and advantages of the present application will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

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 application.

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present application are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.

In the present application, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present application.

The application provides a switching power supply.

In one embodiment of the present application, referring to fig. 1, fig. 1 is a logic block diagram of an embodiment of a switching power supply of the present application, which provides a stable output voltage to a load, the switching power supply includes: the device comprises a detection module 10, a main controller 20 and a switch module 30;

the detection module 10 is connected with a load feedback FB, the detection module 10 is connected with the switch module 30, the switch module 30 is connected with the load F, and the main controller 20 is respectively connected with the detection module 10 and the switch module 30;

the detection module 10 is configured to detect a loop current of the load F, send a close signal to the main controller 20 based on the loop current, and send an open signal to the main controller 20 after a first preset period of time;

the main controller 20 is configured to forward the received turn-off signal and turn-on signal to the switch module 30, count the turn-on signal, and stop forwarding the turn-on signal to the switch module 30 when the number of times of confirming the turn-on signal is greater than a preset number of times;

the switch module 30 is configured to receive the on signal to turn on and to receive the off signal to turn off.

In the prior art, in order to protect a load and a switching power supply when the load is overloaded, a protection mechanism is started, the protection mechanism is used for providing a stable output voltage for the load through the switching power supply when the current of the load is detected to be overloaded, stopping the load from being operated in an overload state to cause damage to the load, detecting whether the current of the load is overloaded or not after a period of time, and providing the stable output voltage for the load through the switching power supply when the current is detected to be overloaded again, so that the internal circuit of the switching power supply and devices of the load are damaged easily due to repeated detection and disconnection, and unnecessary power consumption is also caused. For example, when an electrical device of a load is in a fault state, the switching power supply repeatedly acts between a detection loop current and an off operation, the load needs to be electrified during detection, at the moment, the overload load is extremely easy to cause device damage, and in the process of electrifying and de-electrifying, the switching power supply is damaged due to the repeated processes of charging and discharging, and switching on and off of devices in the switching power supply.

It should be noted that, in an actual application scenario, the main controller may be specifically an MCU, and the main controller is further configured to clear the count after stopping forwarding the start signal to the switch module 30, where the load feedback FB is a pin of the power supply chip, and whether the load is overloaded can be detected through the load feedback FB. The switch module 30 is connected in series in the primary coil of the transformer, the secondary side of the transformer is connected with the load F, and the switch module receives the switch signal to control the transformer to transmit and output primary side energy to the load F.

In this embodiment, the switching power supply provides a stable output voltage for the load, the detection module 10 detects whether the loop current of the load is overloaded, and sends a closing signal to the main controller 20 when detecting that the loop current is greater than a preset current, the main controller 20 forwards the closing signal to the switch module 30, the switch module 30 receives the closing signal and then performs closing operation, the control transformer stops transmitting primary energy to the load F, the load F is protected, the detection module performs delay protection after the switch module 30 is closed, sends an opening signal to the main controller 20 after a preset time period, re-opens the switch module 30, and when the switch module 30 is opened, the detection module 10 re-detects that the loop current is greater than the preset current, at this time, the detection module 10 re-sends the closing signal to the main controller 20, and after the switch module 30 is closed, the detection module re-sends an opening signal to the main controller 20 after the preset time period, and repeats this, at this time, the main controller 20 counts the opening signal sent by the detection module 10, and after confirming whether the number of times of the received opening signals is greater than the preset times, if the number of times of opening signals is greater than the preset times, and the number of times of opening signals are cleared after the detection module is stopped.

In this embodiment, when the main controller 20 confirms that the turn-on signal is greater than the preset number of times, the turn-on signal is stopped to be forwarded to the switch module 30, the switch module 30 cannot receive the turn-on signal to control the transformer to stop transmitting primary energy to the load F, the detection module 10 cannot detect either, the switching power supply is prevented from being repeatedly switched between the on circuit and the off circuit when the current of the load F is in the overload state, the internal circuit of the switch circuit and the devices of the load are damaged, and when the loop current of the load F is restored to be within the current range born by the load in a short time, the main controller forwards the turn-on signal to the switch module 30, the switch module 30 is turned on, that is, the switch module 30 transmits the primary energy of the transformer to the load F, and the load F is prevented from being powered off when the load F is protected, and the experience of the user using the load is prevented from being influenced.

Optionally, in some possible embodiments, the main controller 20 is further configured to forward the start signal to the switch module after a second preset period from the time when the count is cleared.

In this embodiment, when the number of times of detecting the on signal is greater than the preset number of times, the main controller 20 stops forwarding the on signal to the switch module 30, and after counting the second preset time period from the zero clearing time, forwards the on signal to the switch module 30, at this time, after the switch module 30 is turned on, the detecting module 10 detects whether the overload is performed again, and when the overload is performed, the main controller 20 detects the number of times of detecting the on signal again is greater than the preset number of times, and circulates in this way until the loop current of the load is not in the overload state. Thus, the internal circuit of the switching power supply and the devices of the load are prevented from being easily damaged by repeatedly turning on the circuit at high current.

Optionally, in some possible embodiments, referring to fig. 2, fig. 2 is a schematic connection diagram of a main controller of an embodiment of the switching power supply of the present application, where the main controller 20 includes: a counting unit 22 and a forwarding unit 21;

a first end of the forwarding unit 21 is connected with the detection module 10, a second end of the forwarding unit 21 is connected with the switch module 30, and the counting unit 22 is connected with the forwarding unit 21;

the forwarding unit 21 is configured to receive the on signal and the off signal sent by the detection module, and forward the on signal and the off signal to the switch module 30;

the counting unit 22 is configured to count the start signal received by the forwarding unit 21, and send a cut-off signal to the forwarding unit and zero the count when the number of times of confirming the start signal is greater than a preset number of times;

the forwarding unit 21 is further configured to receive the cutoff signal and stop forwarding the start signal to the switch module 30;

the counting unit 22 is further configured to send a recovery signal to the forwarding unit 21 after the second preset time period from the time of counting zero;

the forwarding unit 21 is further configured to receive the recovery signal, and recover forwarding the start signal to the switch module 30.

In this embodiment, the on signal may be a high level, the off signal may be a low level, the forwarding unit 21 converts the high level into a corresponding driving signal after receiving the high level sent by the detection module and sends the driving signal to the switch module 30, the forwarding unit 21 converts the low level into the corresponding driving signal after receiving the low level sent by the detection module and sends the driving signal to the switch module 30, the counting module counts the high level received by the forwarding unit 21, and when it is confirmed that the number of times that the forwarding unit 21 receives the high level is greater than the preset number of times of the high level, sends a cut-off signal to the forwarding unit 21 and clears the count, and the forwarding unit 21 stops converting the high level into the corresponding driving signal after receiving the cut-off signal so as to stop sending the driving signal corresponding to the high level to the switch module 30. Thus, when the loop current of the load F is kept in an overload state, the switching power supply is prevented from repeatedly cycling between off and on, and the internal devices and the load of the switching power supply are prevented from being damaged. And, the counting unit 22 transmits a restoration signal to the forwarding unit 21 after a second preset period from the time of counting zero clearing, and the forwarding unit 21 resumes converting the high level into a corresponding driving signal after receiving the restoration signal to transmit the driving signal corresponding to the high level to the switching module 30.

Optionally, in some possible real-time examples, the forwarding unit 21 includes: a pulse width control unit;

the pulse width control unit is configured to convert the received on signal and off signal into a corresponding pulse width on signal and pulse width off signal, send the corresponding pulse width on signal and pulse width off signal to the switch module 30, stop forwarding the on signal to the switch module 30 when the off signal is received, and forward the on signal to the switch module 30 when the recovery signal is received.

In this embodiment, the forwarding unit 21 may be a pulse width control unit, which is configured to send a pulse width on signal and a pulse width off signal to the switch module 30, and adjust the duty ratio of the switch module 30 according to the pulse width on signal and the pulse width off signal, so as to control on and off of the switch module 30.

Optionally, in some possible embodiments, referring to fig. 3, fig. 3 is a schematic connection diagram of a detection module of an embodiment of the switching power supply of the present application, and the detection module 10 includes: a detection unit 11 and a delay unit 12;

the detection unit 11 is connected between the load feedback FB and the switch module 30, and the delay unit 12 is connected with the detection unit 11 and the forwarding unit 21 respectively.

In this embodiment, the detecting unit 11 is configured to collect a loop current of a load, convert the loop current into a corresponding voltage signal, and then send a level signal corresponding to the voltage signal to the delay unit 12, specifically, send a low level signal to the delay unit 12 when the detecting unit 11 confirms that the voltage signal is lower than a preset first voltage signal in a range where the loop current is borne by the load, and send a high level signal to the delay unit 12 when the detecting unit 11 confirms that the voltage signal is higher than the preset first voltage signal in overload of the loop current. The delay unit 12 is configured to send an on signal to the forwarding unit 21 when the detection unit 11 sends a low level signal, and otherwise send a high level signal to the forwarding unit 21.

Optionally, in some possible embodiments, referring to fig. 4, fig. 4 is a schematic connection diagram of a detection unit of an embodiment of the switching power supply of the present application, and the detection unit 11 includes: the acquisition resistor R1 and the first operation comparator A1;

the collection resistor R1 is connected between the load feedback FB and the switch module 30, the non-inverting input end of the first operation comparator A1 is connected with the connection end of the collection resistor R1 and the switch module 30, the inverting input end of the first operation comparator A1 is connected with a first preset reference voltage Ref1, and the output end of the first operation comparator A1 is connected with the delay unit 12.

In this embodiment, the collecting resistor R1 converts the collected loop current of the load F into a voltage signal, and sends the voltage signal to the first operation comparator A1, the first operation comparator A1 compares the voltage signal with the first preset reference voltage Ref1, and sends a high-level signal to the delay unit 12 when the voltage signal is determined to be greater than the first preset reference voltage Ref1, and sends a low-level signal to the delay unit 12 when the voltage signal is determined to be less than the first preset reference voltage Ref 1.

Optionally, in some possible embodiments, referring to fig. 5, fig. 5 is a schematic diagram of connection of a delay unit of an embodiment of the switching power supply of the present application, where the delay unit 12 includes: the triode J1, the second resistor R2, the capacitor C and the second operation comparator A2;

the output end of the first operation comparator A1 is connected with the base electrode of the triode J1, the emitter electrode of the triode J1 is connected with the inverting input end of the second operation comparator A2, the non-inverting input end of the second operation comparator A2 is connected with a second preset reference voltage Ref2, and the output end of the second operation comparator A2 is connected with the forwarding unit 21;

the second resistor R2 is connected with the capacitor C in parallel, a first end of the second resistor R2 connected with the capacitor C is connected to the inverting input end of the second operation comparator A2, and a second end of the second resistor R2 connected with the capacitor C is grounded.

In this embodiment, when the loop current is in an overload state, the first operational comparator A1 sends a high level to the triode J1, after the triode J1 is turned on, a voltage signal is sent to the second operational comparator A2, the second operational comparator A2 compares the voltage signal with a preset second preset reference voltage Ref2, at this time, the voltage signal is greater than the second preset reference voltage Ref2, the second operational comparator A2 sends a low level signal to the forwarding unit 21, after receiving the low level signal, the forwarding unit 21 turns off the switching module 30, so that the switching power supply stops supplying power to protect the load F, and when the voltage signal is sent to the second operational comparator A2, the capacitor C is charged, after the switching power supply stops supplying power, the capacitor C discharges through a resistor, when the voltage on the capacitor is smaller than Ref2, the second operational comparator A2 outputs the high level signal, after receiving the high level signal, the forwarding unit 21 turns on the switching power supply again to supply power to the switching module 30, that is realized after the loop current is in an overload state, the switching module 30 is turned on again for a preset time. The collector of the transistor is connected to the power supply VCC.

Illustratively, referring to fig. 5, the delay unit 12 may further include: the third resistor R3 and the fourth resistor R4, the third resistor R3 is connected between the second preset reference voltage and the second operational amplifier, the fourth resistor is connected between the in-phase input end and the output end of the second operational amplifier, the third resistor R3 plays a role in raising the resistance, and the fourth resistor R4 plays a role in protecting the second operational amplifier.

Optionally, in some possible embodiments, the switch module 30 includes: a switching tube;

the switching tube is connected in series in the primary winding of the transformer, and the delay unit 12 is connected between the main controller 20 and the switching tube.

In this embodiment, the switching tube may be a MOS tube specifically, and receives the pulse width on signal and the pulse width off signal to conduct on and off, so as to transmit and output primary energy to the load F.

The application provides a switching power supply and a control method thereof, wherein the switching power supply provides stable output voltage for a load, and the switching power supply comprises: the device comprises a detection module, a main controller and a switch module; the detection module is connected with the load feedback FB, the detection module is connected with the switch module, the switch module is connected with the load, and the main controller is respectively connected with the detection module and the switch module; the detection module is used for detecting loop current of the load, sending a closing signal to the main controller based on the loop current, and sending an opening signal to the main controller after a first preset time period; the main controller is used for forwarding the received closing signal and the received opening signal to the switch module, counting the opening signal, and stopping forwarding the opening signal to the switch module when the number of times of confirming the opening signal is larger than the preset number of times; the switch module is used for receiving the on signal to be on and receiving the off signal to be off. The application realizes that the turn-off signal sent by the detection module is forwarded to the switch module through the main controller, after the turn-on signal sent by the detection module is counted, if the turn-on signal frequency is larger than the preset frequency, the turn-on signal is stopped from being forwarded to the switch module, thereby preventing the overload current from being repeatedly conducted to the load when the loop current of the load is always in an overload state, and preventing the switch power supply from being repeatedly switched between the turn-off state and the turn-on state, and further protecting the internal circuit of the switch power supply and the devices of the load.

Based on the first embodiment of the switching power supply described above, an embodiment of a control method of the switching power supply of the present application is presented. In the embodiments of the control method of the switching power supply of the present application, please refer to fig. 6, fig. 6 is a flowchart illustrating a first embodiment of the control method of the switching power supply of the present application. In a first embodiment of the method of the present application, the control method of the switching power supply of the present application includes:

step S10: receiving a switching signal sent by the detection module, and counting the switching signal;

in this embodiment, the main controller receives the start signal sent by the detection module, and counts the start signal.

It should be noted that, the on signal may be a high level signal, the off signal may be a low level signal, specifically, after the detection module collects the loop current of the load and converts the loop current into a voltage signal, when the voltage signal is confirmed to be greater than a preset voltage, the detection module sends the low level signal to the main controller, then the main controller sends the off signal to the switch module, the control transformer stops sending primary energy to the load F, after a preset time when the loop of the load is not electrically connected, the detection module sends the on signal to the main controller, at this time, if the loop current is in an overload state, the detection module repeatedly sends the on signal and the off signal to the main controller, and the main controller forwards the off signal to the switch module and counts the on signal.

Step S20: and confirming whether the switching signal times are greater than preset times, if so, stopping forwarding the starting signal to the switching module and resetting the count.

In this embodiment, the main controller confirms whether the number of times of the start signal is greater than a preset number of times, and if so, stops forwarding the start signal to the switch module.

If the main controller detects that the turn-on signal is greater than the preset times, the loop current of the load is repeatedly disconnected and connected, and the loop current is always in an overload state, at this time, when the turn-on signal times reach the preset times, the turn-on signal is stopped to be forwarded to the switch module, so that the internal circuit of the switch power supply and the devices of the load are prevented from being damaged. And forwarding an opening signal to the switch module after a second preset time period from the moment of counting zero clearing.

Optionally, in some possible embodiments, the main controller includes: the control method of the switching power supply comprises the following steps:

step A: controlling the counting unit to count the starting signals, and confirming whether the times of the starting signals are larger than the preset times, if yes, sending a cut-off signal to the forwarding unit, and resetting the count;

in this embodiment, the main controller controls the counting unit to count the start signal, and confirms whether the number of times of the start signal is greater than a preset number of times, if yes, the cut-off signal is sent to the forwarding unit.

When receiving the turn-on signal, the forwarding unit converts the turn-on signal into a corresponding driving signal and then sends the driving signal to the switch module, and when receiving the turn-off signal sent by the main controller, the forwarding unit stops converting the turn-on signal into the corresponding driving signal and stops forwarding the driving signal to the switch module. The off signal is a signal to stop transmitting the on signal, i.e., not responding to the received on signal.

And (B) step (B): and controlling the forwarding unit to receive the cut-off signal and stopping forwarding the starting signal to the switch module.

In this embodiment, the counting unit counts only the on signal, and since the off signal is provided for protecting the load and the on signal is provided for automatically recovering the switching power supply output, the switching power supply output is turned off when the main controller repeatedly receives the on signal, thereby protecting the load and the internal devices of the switching module. And after a second preset time period from the moment of counting zero clearing, sending a recovery signal to the forwarding unit, controlling the forwarding unit to receive the recovery signal, and recovering to forward the starting signal to the switch module.

In addition, the implementation manners of the embodiment are the same as those of the embodiment and the beneficial effects of the switching power supply, and are not described one by one.

The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the scope of the application, and all equivalent structural changes made by the description of the present application and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the application.

Claims

1. A switching power supply that provides a stable output voltage to a load, the switching power supply comprising: the device comprises a detection module, a main controller and a switch module;

2. The switching power supply of claim 1 wherein said main controller is further configured to forward said on signal to said switching module after a second predetermined period of time from the time of count clearing.

3. The switching power supply of claim 2 wherein said main controller comprises: a counting unit and a forwarding unit;

4. A switching power supply as claimed in claim 3, characterized in that the forwarding unit comprises: a pulse width control unit;

5. A switching power supply as claimed in claim 3, wherein the detection module comprises: the device comprises a detection unit and a delay unit;

6. The switching power supply as claimed in claim 5, wherein the detection unit includes: the acquisition resistor and the first operation comparator;

7. The switching power supply of claim 6 wherein said delay unit comprises: the triode, the second resistor, the capacitor and the second operation comparator;

8. The switching power supply of claim 7 wherein said switching module comprises: a switching tube;

9. A control method of a switching power supply, characterized in that the control method of a switching power supply is applied to the main controller of a switching power supply according to any one of claims 1 to 8, the control method of a switching power supply comprising:

10. The control method of a switching power supply according to claim 9, wherein the main controller includes: the control method of the switching power supply comprises the following steps: