CN216490234U - Power supply circuit and electronic device - Google Patents

Abstract

The utility model provides a power supply circuit and an electronic device, comprising: the device comprises a rectification module, a PFC conversion module, a flyback conversion module and a bypass module; the input side of the rectification module is directly or indirectly connected to a live wire and a zero line of alternating current, the input side of the PFC conversion module is connected with the output side of the rectification module, and the output side of the PFC conversion module is connected with the input side of the flyback conversion module; the bypass module is connected between the input side of the rectification module and the first end of the input side of the flyback conversion module; the circuit state of the PFC conversion module comprises: a first circuit state, and: a second circuit state for conducting discharge with its output side; the bypass module is configured to bypass the rectification module and the PFC conversion module when the PFC conversion module is in the second circuit state such that: and the bypassed rectifying module and the PFC conversion module stop obtaining the electric energy of the alternating current.

Description

Power supply circuit and electronic device

Technical Field

The utility model relates to the field of power supplies, in particular to a power supply circuit and electronic equipment.

Background

In an AC/DC power supply, the load may be powered by converting alternating current to direct current and delivering the direct current to the load at the back end.

In the prior art, in order to meet the current harmonic requirement, a primary PFC conversion module may be added on the basis of a flyback conversion module to adjust the input current harmonic and the power factor of an AC/DC power supply. However, under some conditions (for example, when the input power is light load, but not limited thereto), the operation of the PFC converter module will affect the efficiency and safety of the whole AC/DC.

SUMMERY OF THE UTILITY MODEL

The utility model provides a power supply circuit and electronic equipment, which are used for solving the adverse effect caused by the fact that a PFC conversion module is always connected into the circuit.

According to a first aspect of the present invention, there is provided a power supply circuit comprising: the device comprises a rectification module, a PFC conversion module, a flyback conversion module and a bypass module;

the input side of the rectification module is directly or indirectly connected to a live wire and a zero line of alternating current, the input side of the PFC conversion module is connected with the output side of the rectification module, and the output side of the PFC conversion module is connected with the input side of the flyback conversion module; the bypass module is connected between the input side of the rectification module and the first end of the input side of the flyback conversion module;

the circuit state of the PFC conversion module comprises: a first circuit state for storing the electric energy acquired by the input side of the PFC conversion module, and: a second circuit state for conducting discharge by using the output side of the PFC conversion module;

the bypass module is configured to be capable of:

when the PFC conversion module is in the second circuit state, bypassing the rectification module and the PFC conversion module such that: and the bypassed rectifying module and the PFC conversion module stop obtaining the electric energy of the alternating current.

Optionally, the PFC conversion module is configured to: when the input power of the alternating current is lower than a specified threshold value, the second circuit state is kept, so that the bypass module bypasses the rectifying module and the PFC conversion module when the input power of the alternating current is lower than the specified threshold value.

Optionally, the specified threshold is in the interval range of 50-100W.

Optionally, the bypass module includes a first bypass diode and a second bypass diode;

the positive pole of the first bypass diode is connected with the first end of the input side of the rectifier module, the negative pole of the first bypass diode is connected with the first end of the input side of the flyback conversion module, the positive pole of the second bypass diode is connected with the second end of the input side of the rectifier module, the negative pole of the second bypass diode is connected with the first end of the input side of the flyback conversion module, and the second end of the input side of the flyback conversion module is grounded.

Optionally, the bypass module includes a first bypass switching tube and a second bypass switching tube;

the first bypass switching tube is connected to the first end of the input side of the rectifier module and the first end of the input side of the flyback conversion module, the second bypass switching tube is connected to the second end of the input side of the rectifier module and the first end of the input side of the flyback conversion module, and the second end of the input side of the flyback conversion module is grounded;

the first bypass switching tube and the second bypass switching tube are configured to be controlled to bypass the rectifying module and the PFC conversion module when the PFC conversion module is in the second circuit state.

Optionally, the gates of the first bypass switching tube and the second bypass switching tube are connected to a controller;

the controller is configured to:

when the PFC conversion module is in the second circuit state, the first bypass switching tube and the second bypass switching tube are controlled based on the voltage of the alternating current.

Optionally, a first end of the input side of the rectifying module is directly or indirectly connected to the live wire of the alternating current, and a second end of the input side of the rectifying module is directly or indirectly connected to the zero wire of the alternating current;

the controller is specifically configured to, when controlling the first bypass switching tube and the second bypass switching tube based on the voltage of the alternating current:

when the alternating current is in a positive half period, controlling the first bypass switching tube to be conducted, and controlling the second bypass switching tube to be turned off;

and when the alternating current is in a negative half period, the first bypass switch tube is controlled to be turned off, and the second bypass switch tube is controlled to be turned on.

Optionally, the power circuit further includes a Bulk capacitor, and the PFC conversion module includes a PFC main switching tube, an inductor, a Boost diode, an input capacitor, and a PFC controller;

the first end of the inductor is connected with the first end of the output side of the rectifying module, the second end of the inductor is connected with the anode of the Boost diode, the cathode of the Boost diode is connected with the first end of the input side of the flyback conversion module and the first end of the Bulk capacitor, the first end of the PFC main switching tube is connected with the anode of the Boost diode, the second end of the PFC main switching tube, the second end of the Bulk capacitor and the second end of the output side of the rectifying module are grounded, and the input capacitor is connected in parallel with the two ends of the output side of the rectifying module; and the grid electrode of the PFC main switching tube is connected with the PFC controller.

Optionally, the PFC controller is configured to:

determining the input power of the alternating current;

when the input power is lower than a specified threshold value, controlling the PFC main switching tube to be kept off so that: the PFC conversion module enters the second circuit state, and the bypass module bypasses the PFC conversion module and the rectification module.

Optionally, the PFC conversion module further includes a detection unit, and the detection unit is configured to be capable of detecting an electrical parameter of the alternating current and feeding back a detection result to the PFC controller, so that: the input power can be determined based on the electrical parameter, the electrical parameter including at least one of: voltage, current, power of the alternating current.

Optionally, the power circuit further includes an EMI filter, and the flyback conversion module includes: the transformer, the flyback switching tube and the output diode;

the first end of the primary winding of the transformer is connected with the PFC conversion module and the bypass module to be used as the first end of the input side of the flyback conversion module; the second end of the primary winding of the transformer is connected with the first end of the flyback switching tube, the second end of the flyback switching tube is grounded and serves as the second end of the input side of the flyback conversion module, and the anode of the output diode is connected with the secondary winding of the transformer;

the input side of the EMI filter is connected with the alternating current, and the output side of the EMI filter is connected with the input side of the rectifying module.

According to a second aspect of the present invention, there is provided an electronic device including the power supply circuit according to the first aspect and the alternatives thereof.

In the power circuit and the electronic device provided by the utility model, the bypass module is introduced and is connected between the input side of the rectifier module and the flyback conversion module, so that the rectifier module and the PFC conversion module can be bypassed when the PFC conversion module is in a second circuit state capable of conducting and discharging on the output side of the PFC conversion module, and further, a circuit mechanism capable of bypassing the PFC conversion module is formed, so that the PFC conversion module is prevented from always working in the circuit; for example: when the input power is lower (namely lower than a designated threshold value, namely light load), the bypass module is used for bypassing the rectifier module and the PFC conversion module, so that the PFC conversion module does not work, and the efficiency in the light load can be effectively improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a first circuit schematic of an exemplary power supply circuit in an embodiment of the utility model;

FIG. 2 is a second exemplary circuit schematic of a power supply circuit in accordance with an embodiment of the present invention;

FIG. 3 is a third circuit schematic of an exemplary power supply circuit in an embodiment of the utility model;

FIG. 4 is a fourth circuit schematic of an exemplary power supply circuit in an embodiment of the present invention;

FIG. 5 is a fifth circuit schematic of an exemplary power supply circuit in an embodiment of the utility model;

FIG. 6 is a sixth exemplary electrical schematic diagram of a power circuit in accordance with an embodiment of the present invention;

fig. 7 is a seventh circuit schematic of an exemplary power supply circuit in an embodiment of the utility model.

Description of reference numerals:

10-a rectifying module;

20-PFC conversion module;

21-PFC main switching tube;

22-a PFC controller;

23-a detection unit;

30-a flyback conversion module;

40-a bypass module;

41-first bypass switching tube;

42-a second bypass switching tube;

50-an EMI filter;

Q1-PFC main switching tube;

q2-flyback controller;

d1 — first bypass diode;

d2 — second bypass diode;

lb-inductance;

a Db-Boost diode;

cin — input capacitance;

a Cbulk-Bulk capacitor;

a T-transformer;

d-output diode.

Detailed Description

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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the utility model described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The technical solution of the present invention will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

Referring to fig. 1 to 7, a power circuit includes: the circuit comprises a rectifying module 10, a PFC conversion module 20, a flyback conversion module 30 and a bypass module 40.

The input side of the rectification module 10 is directly or indirectly connected to a live line (e.g., L shown in the figure) and a neutral line (e.g., N shown in the figure) of the alternating current, the input side of the PFC conversion module 20 is connected to the output side of the rectification module 10, and the output side of the PFC conversion module 20 is connected to the input side of the flyback conversion module 30; the bypass module 40 is connected between the input side of the rectifier module 10 and the first end of the input side of the flyback converter module 30;

the circuit states of the PFC converter module 20 include: a first circuit state for storing the electric energy acquired by the input side of the PFC conversion module, and: and the second circuit state is used for utilizing the output side of the PFC conversion module to conduct discharge.

The first circuit state is understood to be a circuit state capable of storing energy, in which the output side is not normally discharged; specifically, the first circuit state may be understood as a circuit state when the PFC main switch tube 21 is turned on;

the second circuit state can be understood as: in the second circuit state, as long as the PFC conversion module stores the electric energy, the output side may be used for conducting discharge, and in the second circuit state, the output side may be in the second circuit state, where the output side may be in the second circuit state, and may also be in the second circuit state, where the output side may not actually discharge due to the fact that the output side has been discharged or the electric energy is not stored; specifically, the second circuit state may be understood as a circuit state when the PFC main switching tube 21 is turned off, which may be a short-time turn-off realized by controlling the PFC main switching tube based on a PWM signal in a process of realizing conversion by the PFC conversion module, or may be a turn-off maintenance realized by controlling the PFC main switching tube to keep turning off based on a turn-off signal (which may also be understood as a turn-off signal) when the PFC conversion module does not need to work (which may also be regarded as controlling PWM turn-off of the PFC main switching tube).

The bypass module 40 is configured to be able to:

when the PFC converter module 20 is in the second circuit state, the rectifier module 10 and the PFC converter module 20 are bypassed, so that: and the bypassed rectifying module and the PFC conversion module stop obtaining the electric energy of the alternating current.

The bypass of the rectifying module and the PFC conversion module may be: therefore, the flyback conversion module 30 can still obtain the electric energy to perform a process of working, and further, any circuit module capable of realizing the process does not depart from the scope of the embodiment of the present invention.

By introducing the bypass module, the bypass module is connected between the input side of the rectifier module and the flyback conversion module, so that the rectifier module and the PFC conversion module can be bypassed when the PFC conversion module is in a second circuit state capable of conducting and discharging on the output side of the PFC conversion module.

In one embodiment, the PFC converter module 20 is configured to: when the input power of the alternating current is lower than a specified threshold value, the second circuit state is kept, so that the bypass module bypasses the rectifying module and the PFC conversion module when the input power of the alternating current is lower than the specified threshold value.

The specified threshold may be understood as a value that can determine whether the light load is present, and in an example, the specified threshold may be in an interval of 50-100W, for example, 75W. According to different applied scenes and different specifications of alternating current, the acquired specified threshold value can be adapted and changed according to requirements.

In the case of adding one stage of PFC converter module, when the input power is light load (for example, less than 75W), the efficiency of the AC/DC power supply for two-stage conversion is liable to be reduced, and in order to improve the efficiency of the power supply at light load, the PFC converter module may be turned off (for example, the main PFC switching tube is controlled to be kept off), so as to make the PFC converter module not work.

Furthermore, the implementation manner in which the input power is determined and compared with the specified threshold may be implemented based on software, or may be implemented based on hardware (for example, using a power meter, a comparator, etc.), or may be implemented by combining software and hardware, and in the case that the input power is determined and compared, any existing or improved manner in the art for determining the input power and comparing the input power with the specified threshold may be applied as an alternative.

In the above scheme, when the input power is low (i.e. lower than the specified threshold, i.e. light load), the bypass module is used to bypass the rectifier module and the PFC conversion module, so that the PFC conversion module does not operate, thereby effectively improving the efficiency in light load.

In some solutions different from the embodiments of the present invention, a specific diode may be connected in parallel between the input side and the output side of the PFC converter module, however, since the signal rectified by the rectifier module is still transmitted to the PFC converter module, the output side of the PFC converter module is still conducted (for example, the Boost diode Db of the PFC converter module and the specific diode are still in a non-conducting state), the efficiency of the entire AC/DC power supply is still reduced, and the efficiency is further reduced as the load is further reduced (which may be regarded as further reduction of the input power).

In one embodiment, referring to fig. 2, fig. 3, fig. 5 and fig. 7, the power circuit further includes a Bulk capacitor Cbulk, and the PFC conversion module 20 includes a PFC main switch 21, an inductor Lb, a Boost diode Db, an input capacitor Cin, and a PFC controller 22.

A first end of the inductor Lb is connected to a first end of the output side of the rectifier module 10, a second end of the inductor Lb is connected to an anode of the Boost diode Db, a cathode of the Boost diode Db is connected to a first end of the input side of the flyback conversion module 30 and a first end of the Bulk capacitor Cbulk, a first end of the PFC main switch tube 21 (i.e., the switch tube Q1) is connected to an anode of the Boost diode Db, a second end of the PFC main switch tube 21 (i.e., the switch tube Q1), a second end of the Bulk capacitor Cbulk, and a second end of the output side of the rectifier module 10 are grounded, and the input capacitor Cin is connected in parallel to two ends of the output side of the rectifier module 10; the gate of the main PFC switch tube 21 (i.e., the switch tube Q1) is connected to the PFC controller 22, so that on/off variation can be realized under the control of the PFC controller 22.

During a normal operation, the PFC controller 22 may output a PWM signal to control the on/off variation of the main PFC switch 21 (i.e., the switch Q1), so as to output a required converted voltage at the output side of the PFC converter module.

In one embodiment, the PFC controller 22 is configured to:

determining the input power of the alternating current; specifically, the power of the alternating current can be detected as the output power, and the power of the input side of the rectifier module 10 can also be detected to represent the input power;

when the input power is lower than a specified threshold (e.g. 75W), the PFC main switch tube 21 (i.e. the switch tube Q1) is controlled to remain off, so that: the PFC converter module enters the second circuit state, and the bypass module bypasses the PFC converter module and the rectifier module, at this time, the PFC controller 22 may output a turn-off signal (which may also be understood as a turn-off signal) to the PFC main switch tube 21 (i.e., the switch tube Q1).

The PFC main switch tube 21 may be a switch tube Q1 shown in fig. 5 and fig. 7, which is an NMOS tube, and in other examples, the switch tube Q1 may also be implemented by a triode or other transistors or a combination of transistors.

In addition, the circuit of the PFC converter module 20 may be understood based on the PFC converter module that is already available or improved in the art, and may be changed in any way without departing from the scope of the embodiment of the present invention.

In a further example, the PFC converter module 20 further includes a detection unit 23, where the detection unit 23 is configured to be able to detect an electrical parameter of the alternating current, and feed back a detection result to the PFC controller, so that: the input power can be determined based on the electrical parameter;

wherein the electrical parameter comprises at least one of: the voltage, the current, and the power of the alternating current, and further, the PFC controller 22 of the PFC conversion module 20 may directly use the detected power as the input power to determine whether the detected power is lower than a specified threshold, and the PFC controller 22 may also calculate the input power based on the voltage and the current to determine whether the detected power is lower than the specified threshold.

Any manner of detecting and calculating power, whether existing or modified, in the art may be used as an alternative to the embodiments of the present invention without departing from the scope of the embodiments of the present invention.

In an implementation circuit of the bypass module 40, referring to fig. 4 and fig. 5, the bypass module 40 includes a first bypass diode D1 and a second bypass diode D2;

the positive pole of first bypass diode D1 is connected the first end of rectifier module 10 input side, can directly or indirectly be connected to the live wire, the negative pole of first bypass diode D1 is connected the first end of flyback conversion module 30 input side, specifically can directly or indirectly be connected to the first end of transformer T primary winding, the positive pole of second bypass diode D2 is connected the second end of rectifier module 10 input side, can directly or indirectly be connected to the zero line, the negative pole of second bypass diode D2 is connected the first end of flyback conversion module input side, specifically can directly or indirectly be connected to the first end of transformer T primary winding, the second end ground connection of flyback conversion module 30 input side.

In the above scheme, taking fig. 5 as an example, when the input power of the AC/DC power supply (i.e., the power circuit) is lower than a specified threshold (e.g., 75W), the PWM of the control switch Q1 is turned off (i.e., the control switch Q1 is kept off), at this time, the first bypass diode D1 and the second bypass diode D2 bypass the entire PFC converter module, and the rectifier bridge (i.e., the rectifier module) and the Boost diode Db are not turned on any more, so as to greatly improve the efficiency of the AC/DC power supply.

In another implementation circuit of the bypass module 40, the bypass module 40 includes a first bypass switching tube 41 (i.e., the switching tube Q3) and a second bypass switching tube 42 (i.e., the switching tube Q4);

the first bypass switching tube 41 (i.e., the switching tube Q3) is connected to the first end of the input side of the rectifier module 10 and the first end of the input side of the flyback converter module 30, the second bypass switching tube 42 (i.e., the switching tube Q4) is connected to the second end of the input side of the rectifier module 10 and the first end of the input side of the flyback converter module 30, and the second end of the input side of the flyback converter module 30 is grounded;

the first bypass switching tube may be connected with reference to the first bypass diode with respect to a connection relationship between the rectifier module and the flyback conversion module, and the second bypass switching tube may be connected with reference to the second bypass diode with respect to a connection relationship between the rectifier module and the flyback conversion module.

The first bypass switch tube 41 (i.e., the switch tube Q3) and the second bypass switch tube 42 (i.e., the switch tube Q4) are configured to be controlled to bypass the rectifier module 10 and the PFC converter module 20 when the PFC converter module 20 is in the second circuit state.

In some examples, the first bypass switching tube and the second bypass switching tube may be controlled to be kept on all the time, in other examples, the first bypass switching tube and the second bypass switching tube may be controlled to be on when the input power is lower than the specified threshold, and the remaining time is kept off, in still other examples, the on-off states of the first bypass switching tube and the second bypass switching tube may also be changed when the input power is lower than the specified threshold, for example: the first bypass switch tube and the second bypass switch tube can change along with the positive half period and the negative half period of the alternating current voltage; in addition, when the input power is not lower than the specified threshold, the first bypass switching tube and the second bypass switching tube may be turned on or off, or may vary with the positive and negative half-cycles of the ac voltage. Specifically, the gates of the first bypass switching tube 41 and the second bypass switching tube 42 are connected to a controller; the controller may be, for example, the PFC controller 22, and in other examples, the controller may also be a controller dedicated to control the bypass switching tube, which does not exclude the solution of adopting a flyback controller in a flyback conversion module.

The controller (e.g., PFC controller 22) is configured to:

when the PFC converter module 20 is in the second circuit state (for example, when the input power is lower than the specified threshold), the first bypass switching tube and the second bypass switching tube are controlled based on the voltage of the alternating current.

The first end of the input side of the rectifying module is directly or indirectly connected to the live wire of the alternating current, and the second end of the input side of the rectifying module is directly or indirectly connected to the zero wire of the alternating current;

therefore, when the controller (for example, a PFC controller) controls the first bypass switching tube and the second bypass switching tube based on the voltage of the alternating current, the controller is specifically configured to:

when the alternating current is in a positive half period, controlling the first bypass switching tube to be conducted, and controlling the second bypass switching tube to be turned off;

and when the alternating current is in a negative half period, the first bypass switching tube is controlled to be turned off, and the second bypass switching tube is controlled to be turned on.

In an example, a controller (e.g., a PFC controller) may detect a voltage of the ac power through the detection unit 23 to determine whether the ac power is in a positive half period or a negative half period, and control the first bypass switching tube and the second bypass switching tube based on the determination.

Taking fig. 7 as an example, when the input power is lower than a specified threshold (for example, 75W), the PWM of the PFC converter module is turned off (i.e., the control switch Q1 is kept off), at this time, the first bypass switch Q3 and the second bypass switch Q4 bypass the PFC converter module, and by detecting positive and negative half cycles of the input AC bus voltage (i.e., positive and negative changes of the AC voltage), the on control of the first bypass switch Q3 and the second bypass switch Q4 can be realized, so as to further improve the efficiency of the two-stage AC/DC power supply system.

In one embodiment, referring to fig. 5 and 7, the power circuit further includes an EMI filter 50; the input side of the EMI filter 50 is connected with the alternating current, and the output side of the EMI filter 50 is connected with the input side of the rectifying module. In other embodiments, it is also possible to eliminate the EMI filter or to use other filtering modules.

In one embodiment, the flyback converter module 30 includes: a transformer T, a flyback switching tube (i.e. a switching tube Q2) and an output diode D;

a first end of a primary winding of the transformer T is connected to the PFC conversion module 20 and the bypass module 40, and serves as a first end of an input side of the flyback conversion module; a second end of the primary winding of the transformer T is connected to a first end of the flyback switching tube (i.e., the switching tube Q2), a second end of the flyback switching tube (i.e., the switching tube Q2) is grounded to serve as a second end of the input side of the flyback conversion module 30, and an anode of the output diode D is connected to a secondary winding of the transformer T.

In various alternatives of the embodiment of the present invention, the circuit of the flyback converter module 30 may not be limited to the circuit shown in fig. 5 and fig. 7, and any improved circuit or change based on this may be used, whether existing or improved, without departing from the scope of the embodiment of the present invention.

In one embodiment, the rectifier module 10 may adopt a full-wave rectifier bridge including four rectifier diodes, in other embodiments, the rectifier module 10 may also adopt a half-wave rectifier bridge, and if the half-wave rectifier bridge is adopted, the number of the bypass diodes or the bypass switching tubes in the bypass module may also be one (for example, only the first bypass diode or the first bypass switching tube is adopted). In addition, the bypass module can also be realized by adopting a combination of a bypass diode and a bypass switch tube.

The embodiment of the utility model also provides electronic equipment comprising the power supply circuit related to the alternative scheme.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the utility model has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A power supply circuit, comprising: the device comprises a rectification module, a PFC conversion module, a flyback conversion module and a bypass module; the rectification module adopts a full-wave rectification bridge comprising four rectification diodes;

the input side of the rectification module is directly or indirectly connected to a live wire and a zero line of alternating current, the input side of the PFC conversion module is connected with the output side of the rectification module, and the output side of the PFC conversion module is connected with the input side of the flyback conversion module; the bypass module is connected between the input side of the rectification module and the first end of the input side of the flyback conversion module;

the circuit state of the PFC conversion module comprises: a first circuit state for storing the electric energy acquired by the input side of the PFC conversion module, and: a second circuit state for conducting discharge by using the output side of the PFC conversion module;

the bypass module is configured to bypass the rectification module and the PFC conversion module when the PFC conversion module is in the second circuit state such that: the bypassed rectifying module and the PFC conversion module stop obtaining the electric energy of the alternating current;

the flyback conversion module includes: the transformer, the flyback switching tube and the output diode;

the first end of the primary winding of the transformer is connected with the PFC conversion module and the bypass module to be used as the first end of the input side of the flyback conversion module; the second end of the primary winding of the transformer is connected with the first end of the flyback switching tube, the second end of the flyback switching tube is grounded and serves as the second end of the input side of the flyback conversion module, and the anode of the output diode is connected with the secondary winding of the transformer.

2. The power supply circuit of claim 1, wherein the PFC conversion module is configured to: when the input power of the alternating current is lower than a specified threshold value, the second circuit state is kept, so that the bypass module bypasses the rectifying module and the PFC conversion module when the input power of the alternating current is lower than the specified threshold value.

3. A power supply circuit as claimed in claim 2, wherein the specified threshold is in the interval 50-100W.

4. The power supply circuit of claim 1, wherein the bypass module comprises a first bypass diode and a second bypass diode;

the positive pole of the first bypass diode is connected with the first end of the input side of the rectifier module, the negative pole of the first bypass diode is connected with the first end of the input side of the flyback conversion module, the positive pole of the second bypass diode is connected with the second end of the input side of the rectifier module, the negative pole of the second bypass diode is connected with the first end of the input side of the flyback conversion module, and the second end of the input side of the flyback conversion module is grounded.

5. The power circuit of claim 2, wherein the bypass module comprises a first bypass switching tube and a second bypass switching tube;

the first bypass switching tube is connected to the first end of the input side of the rectifier module and the first end of the input side of the flyback conversion module, the second bypass switching tube is connected to the second end of the input side of the rectifier module and the first end of the input side of the flyback conversion module, and the second end of the input side of the flyback conversion module is grounded;

the first bypass switching tube and the second bypass switching tube are configured to be controlled to bypass the rectifying module and the PFC conversion module when the PFC conversion module is in the second circuit state.

6. The power supply circuit according to any one of claims 1 to 5, further comprising a Bulk capacitor, wherein the PFC conversion module comprises a PFC main switching tube, an inductor, a Boost diode, an input capacitor, and a PFC controller;

the first end of the inductor is connected with the first end of the output side of the rectifying module, the second end of the inductor is connected with the anode of the Boost diode, the cathode of the Boost diode is connected with the first end of the input side of the flyback conversion module and the first end of the Bulk capacitor, the first end of the PFC main switching tube is connected with the anode of the Boost diode, the second end of the PFC main switching tube, the second end of the Bulk capacitor and the second end of the output side of the rectifying module are grounded, and the input capacitor is connected in parallel with the two ends of the output side of the rectifying module; and the grid electrode of the PFC main switching tube is connected with the PFC controller.

7. The power supply circuit according to claim 6,

the PFC controller is configured to:

determining the input power of the alternating current;

when the input power is lower than a specified threshold value, controlling the PFC main switching tube to be kept off so that: the PFC conversion module enters the second circuit state, and the bypass module bypasses the PFC conversion module and the rectification module.

8. The power supply circuit of claim 7, wherein the PFC conversion module further comprises a detection unit configured to detect an electrical parameter of the AC power and feed back a detection result to the PFC controller such that: the input power can be determined based on the electrical parameter, the electrical parameter including at least one of: voltage, current, power of the alternating current.

9. The power supply circuit according to any one of claims 1 to 5, further comprising an EMI filter,

the input side of the EMI filter is connected with the alternating current, and the output side of the EMI filter is connected with the input side of the rectifying module.

10. An electronic device characterized by comprising the power supply circuit of any one of claims 1 to 9.

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