Module valley filling circuit and switching power supply

Abstract

The utility model discloses a module valley-fill circuit and a switching power supply. The module valley-fill circuit comprises a first valley-fill modular circuit, a second valley-fill modular circuit, a first module valley-fill tube, a second module valley-fill tube and a first diode. The control end of the first module valley-fill tube and the control end of the second module valley-fill tube are connected with a first PWM signal, and the first module valley-fill tube and the second module valley-fill tube are used for controlling on and off according to the first PWM signal. And then the first millet filling module circuit and the second millet filling module circuit are controlled to be connected in parallel or in series. According to the utility model, the valley filling circuit is modularly connected for use, so that the transformer is ultrathin and the original power limitation is broken through; and meanwhile, windings can be added while the module valley filling circuit is used, so that the input voltage range and the output power are widened, and the reliability and the high efficiency of the switching power supply are greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of switching power supply especially suitable for a module fills valley circuit and switching power supply. BACKGROUND

[0002] In the Chinese patent application with publication number CN114337250A, a valley filling circuit is proposed, as shown in the figure, the switching power supply includes main power winding switching circuit, energy storage unit, valley filling tube and second diode D2, wherein the main power winding switching circuit has inductance L1, inductance L2, first main power switch tube Q3 and second main power switch tube Q4; the energy storage unit includes capacitors C1, C2; the valley filling tube includes Q1, Q2; Figure 1

[0003] Wherein, the first end of inductance L1 is connected with the positive input end of switching power supply, the first end of energy storage unit C1, the first end of first main power switch tube Q3 and the first end of valley filling tube Q2, the second end is connected with the first end of first main power switch tube Q3, the second end of first main power switch tube Q3 is connected with the second end of energy storage unit C1, the anode of second diode D2 and the first end of valley filling tube Q1, the first end of inductance L2 is connected with the second end of valley filling tube Q2, the cathode of second diode D2, the first end of energy storage unit C2 and the first end of second main power switch tube Q4, the second end of second main power switch tube Q4 is connected with the second end of energy storage unit C2, the second end of valley filling tube Q1 and the input ground end of switching power supply;

[0004] The control end of valley filling tube Q1 and Q2 is used for accessing the same PWM signal, when the input voltage of switching power supply is low voltage, the PWM signal is high level, to drive valley filling tube Q1 and Q2 to turn on, so that energy storage unit C1 and energy storage unit C2 are charged in parallel in the low voltage input stage of switching power supply, improve the capacitance value, when the input voltage of switching power supply is high voltage, the PWM signal is low level, to drive valley filling tube Q1 and Q2 to turn off, so that energy storage unit C1 and energy storage unit C2 are charged in series in the low voltage input stage of switching power supply, improve the capacitor withstand voltage.

[0005] ​The maximum voltage that a commonly used switch tube can withstand is limited, so the maximum voltage that a conventional valley fill circuit can withstand is also limited, and the existing valley fill circuit can meet the requirements of most input voltage ranges. However, with the increasing application of switching power supplies in the photovoltaic industry, the demand for wide input voltage and high power of switching power supplies and application scenarios are gradually increasing. When the input voltage requirement far exceeds the maximum specification of the switch tube, i.e., the maximum withstand voltage of the circuit, the original valley fill circuit cannot meet the requirements any more. If the specification of the single-stage switch tube is increased to meet the input voltage requirement, the cost will also increase greatly. When the output power requirement increases, due to the limited size of the transformer and the power limitation of the valley fill circuit technology, the feasibility of the conventional valley fill circuit solution is greatly reduced, and it is also not conducive to the universality and reliability of the application of switching power supplies. Therefore, a technology is needed to greatly increase the input voltage range on the basis of the original valley fill circuit technology. Practical new type content

[0006] Therefore, the technical problem to be solved by the present application is to overcome the problem that the prior art cannot meet the wide input voltage range and high power output. The present application provides a module valley fill circuit and a switching power supply, which realizes a multi-winding structure on the basis of the original technology to break through the output power limitation, and realizes a module valley fill technology to widen the input voltage range, thereby improving the universality and reliability of the application of switching power supplies.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] In a first aspect, the present application provides a module valley fill circuit applied to a switching power supply, which comprises a first valley fill sub-module circuit, a second valley fill sub-module circuit, a first module valley fill tube, a second module valley fill tube and a first diode.

[0009] The first end of the first valley fill sub-module circuit is connected to the first end of the first module valley fill tube, the second end of the first valley fill sub-module circuit is connected to the first end of the second module valley fill tube, and the third end of the first valley fill sub-module circuit is connected to the anode of the first diode.

[0010] The first end of the second valley fill sub-module circuit is connected to the second end of the first module valley fill tube, the second end of the second valley fill sub-module circuit is connected to the second end of the second module valley fill tube, and the third end of the first valley fill sub-module circuit is connected to the cathode of the first diode.

[0011] The control end of the first module valley fill tube and the control end of the second module valley fill tube are connected to a first PWM signal, and the first module valley fill tube and the second module valley fill tube are used to control the turn-on and turn-off according to the first PWM signal, thereby controlling the first valley fill sub-module circuit and the second valley fill sub-module circuit to be connected in parallel or in series.

[0012] Optionally, the first valley filling sub-module circuit comprises a first main power winding switch circuit, a second main power winding switch circuit, a first energy storage unit, a second energy storage unit, a first winding valley filling tube, a second winding valley filling tube and a second diode;

[0013] The first main power winding switch circuit unit comprises a first winding and a first main power switch tube, a first end of the first winding is connected with a first end of the first energy storage unit, a first end of the second winding valley filling tube and a positive input end of the switching power supply, a second end of the first winding is connected with a first end of the first main power switch tube, a second end of the first main power switch tube is connected with a second end of the first energy storage unit, an anode of the second diode and a first end of the first winding valley filling tube, a control end of the first winding valley filling tube and a control end of the second winding valley filling tube are connected with a second PWM signal;

[0014] The second main power winding switch circuit unit comprises a second winding and a second main power switch tube, a first end of the second winding is connected with a first end of the second energy storage unit, a cathode of the second diode, a second end of the second winding valley filling tube, a second end of the second winding is connected with a first end of the second main power switch tube, a second end of the second main power switch tube is connected with a second end of the second energy storage unit, a second end of the first winding valley filling tube and an anode of the first diode as a third end of the first valley filling sub-module circuit;

[0015] A second end of the first winding valley filling tube is connected to a first end of the first module valley filling tube, and a first end of the second module valley filling tube is connected to a first end or a second end of the second winding valley filling tube.

[0016] Optionally, the second valley filling sub-module circuit comprises a third main power winding switch circuit, a fourth main power winding switch circuit, a third energy storage unit, a fourth energy storage unit, a third winding valley filling tube, a fourth winding valley filling tube and a third diode;

[0017] The third main power winding switch circuit unit comprises a third winding and a third main power switch tube, a first end of the third winding is connected with a first end of the third energy storage unit, a first end of the fourth winding valley filling tube and a cathode of the first diode, a second end of the third winding is connected with a first end of the third main power switch tube, a second end of the third main power switch tube is connected with a second end of the third energy storage unit, an anode of the third diode and a first end of the third winding valley filling tube, a control end of the third winding valley filling tube and a control end of the fourth winding valley filling tube are connected with a second PWM signal;

[0018] The fourth main power winding switch circuit unit comprises a fourth winding and a fourth main power switch tube, a first end of the fourth winding is connected with a first end of the fourth energy storage unit, a cathode of the third diode and a second end of the fourth winding tube, a second end of the fourth winding is connected with a first end of the fourth main power switch tube, and a second end of the fourth main power switch tube is connected with a second end of the fourth energy storage unit and a second end of the third winding tube.

[0019] The first end of the fourth winding tube is connected to the second end of the second module tube, and the second end of the first module tube is connected to the first end or the second end of the third winding tube.

[0020] Optionally, the first end of the second module tube is connected to the second end of the second winding tube, and the second end of the first module tube is connected to the first end of the third winding tube.

[0021] Optionally, the first PWM signal and the second PWM signal are logically identical.

[0022] Optionally, the first end of the second module tube is connected to the first end of the second winding tube, and the second end of the first module tube is connected to the second end of the third winding tube.

[0023] Optionally, the first PWM signal and the second PWM signal are not logically identical.

[0024] Optionally, the first winding and the second winding are coupled to the same transformer.

[0025] Optionally, the third winding and the fourth winding are coupled to the same transformer.

[0026] In a second aspect, the utility model also provides a switching power supply, the switching power supply includes a module valley circuit as described in the first aspect.

[0027] Compared with the prior art, the utility model has the beneficial effects that:

[0028] 1. The utility model increases the number of transformers to widen the original power limit, increase the output power, and widen the input voltage application range. When facing the demand for high power in actual application, the original transformer size does not need to be increased, which not only saves the cost but also improves the universality and reliability of the module valley circuit technology under different application demand conditions.

[0029] 2. The utility model connects the first valley sub-module circuit and the second valley sub-module circuit through the control end of the first module tube and the second module tube, realizes the widening of the input voltage range by increasing the module valley circuit.

[0030] The utility model discloses a module valley fill circuit technology by increasing one level to the original valley fill circuit, under the condition that the original valley fill circuit switch tube specification is unchangeable, this technology can widen the range of input voltage, to satisfy the demand of input voltage range wider and wider in practical application, improve the universality and reliability of switching power supply under different application demand conditions. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is the principle view of prior art valley fill circuit;

[0032] Figure 2 It is the principle view of the utility model kind module valley fill circuit first embodiment for switching power supply;

[0033] Figure 3 It is the principle view of the utility model kind module valley fill circuit second embodiment for switching power supply;

[0034] Figure 4 It is the principle view of the utility model kind module valley fill circuit third embodiment for switching power supply. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purpose, features and advantages of the utility model more apparent, obvious and easy to understand, the specific embodiment of the utility model is described in detail below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0036] It should be noted that the terms "include" and "have" and any variations thereof described in the specification and claims of the present application are intended to cover non-exclusive inclusion, for example, a series of components or unit circuits described in the specification and claims of the present application are not necessarily limited to those clearly listed, but can include components or unit circuits not clearly listed or inherent to these circuits.

[0037] First embodiment

[0038] Figure 2 It is the principle view of the module valley fill circuit for switching power supply in the embodiment, the utility model discloses a kind of module valley fill circuit, it is applied to switching power supply, the module valley fill circuit includes first valley fill submodule circuit 100, second valley fill submodule circuit 200, first module valley fill tube Q9, second module valley fill tube Q10 and first diode D1;

[0039] The first end of the first valley filling sub-module circuit 100 is connected to the first end of the first module valley filling tube Q9, the second end of the first valley filling sub-module circuit 100 is connected to the first end of the second module valley filling tube Q10, and the third end of the first valley filling sub-module circuit 100 is connected to the anode of the first diode D1.

[0040] The first end of the second valley filling sub-module circuit 200 is connected to the second end of the first module valley filling tube Q9, the second end of the second valley filling sub-module circuit 200 is connected to the second end of the second module valley filling tube Q10, and the third end of the first valley filling sub-module circuit 100 is connected to the cathode of the first diode D1.

[0041] The control end of the first module valley filling tube Q9 and the control end of the second module valley filling tube Q10 are connected to a first PWM signal, and the first module valley filling tube Q9 and the second module valley filling tube Q10 are used to control turn-on and turn-off according to the first PWM signal, thereby controlling the first valley filling sub-module circuit 100 and the second valley filling sub-module circuit 200 in parallel or in series.

[0042] The winding valley filling tube is used to control turn-on and turn-off by PWM, thereby controlling the parallel or series connection of the main power winding switching circuits of each module.

[0043] Specifically, the first valley filling sub-module circuit 100 includes a first main power winding switching circuit, a second main power winding switching circuit, a first energy storage unit C1, a second energy storage unit C2, a first winding valley filling tube Q1, a second winding valley filling tube Q2, and a second diode D2.

[0044] The first main power winding switching circuit unit includes a first winding L1 and a first main power switching tube Q3, the first end of the first winding L1 is connected to the first end of the first energy storage unit C1, the first end of the second winding valley filling tube Q2, and the positive input end of the switching power supply, the second end of the first winding L1 is connected to the first end of the first main power switching tube Q3, the second end of the first main power switching tube Q3 is connected to the second end of the first energy storage unit C1, the anode of the second diode D2, and the first end of the first winding valley filling tube Q1, and the control end of the first winding valley filling tube Q1 and the control end of the second winding valley filling tube Q2 are connected to a second PWM signal.

[0045] The second main power winding switch circuit unit comprises a second winding L2 and a second main power switch Q4, a first end of the second winding L2 is connected with a first end of the second energy storage unit C2, a cathode of the second diode D2, and a second end of the second winding valley fill tube Q2, a second end of the second winding L2 is connected with a first end of the second main power switch Q4, a second end of the second main power switch Q4 is connected with a second end of the second energy storage unit C2, a second end of the first winding valley fill tube Q1, and an anode of the first diode D1 as a third end of the first valley fill sub-module circuit 100;

[0046] Specifically, the second valley fill sub-module circuit 200 comprises a third main power winding switch circuit, a fourth main power winding switch circuit, a third energy storage unit C3, a fourth energy storage unit C4, a third winding valley fill tube Q8, a fourth winding valley fill tube Q5, and a third diode D3.

[0047] The third main power winding switch circuit unit comprises a third winding L3 and a third main power switch Q7, a first end of the third winding L3 is connected with a first end of the third energy storage unit C3, a first end of the fourth winding valley fill tube Q5, and a cathode of the first diode D1, a second end of the third winding L3 is connected with a first end of the third main power switch Q7, a second end of the third main power switch Q7 is connected with a second end of the third energy storage unit C3, an anode of the third diode D3, and a first end of the third winding valley fill tube Q8, a control end of the third winding valley fill tube Q8 and a control end of the fourth winding valley fill tube Q5 are connected with a second PWM signal;

[0048] The fourth main power winding switch circuit unit comprises a fourth winding L4 and a fourth main power switch Q6, a first end of the fourth winding L4 is connected with a first end of the fourth energy storage unit C4, a cathode of the third diode D3, and a second end of the fourth winding valley fill tube Q5, a second end of the fourth winding L4 is connected with a first end of the fourth main power switch Q6, a second end of the fourth main power switch Q6 is connected with a second end of the fourth energy storage unit C4 and a second end of the third winding valley fill tube Q8;

[0049] A first end of the second module valley fill tube Q10 is connected to a second end of the second winding valley fill tube Q2, and a second end of the first module valley fill tube Q9 is connected to a first end of the third winding valley fill tube Q8.

[0050] Specifically, the first PWM signal and the second PWM signal are logically identical.

[0051] The connection relationship of the valley fill power supply circuit is as follows:

[0052] The primary circuit, the positive input end Vin+ of the switching power supply is connected with one end of the first energy storage unit C1, one end of the first winding L1, and the first end of the second winding thyristor Q2; the first end of the first main power switch Q3 is connected with the other end of the first winding L1, the second end is connected with the other end of the first energy storage unit C1, the anode of the second diode D2, and the first end of the first winding thyristor Q1; one end of the second winding L2 is connected with the second end of the second winding thyristor Q2, the cathode of the second diode D2, one end of the second energy storage unit C2, and the first end of the second module thyristor Q10; the first end of the second main power switch Q4 is connected with the other end of the second winding L2, and the second end is connected with the other end of the second energy storage unit C2, the second end of the first winding thyristor Q1, the anode of the first diode D1, and the first end of the first module thyristor Q9; one end of the third winding L3 is connected with the cathode of the first diode D1, one end of the third energy storage unit C3, the second end of the second module thyristor Q10, and the first end of the fourth winding thyristor Q5; the first end of the third main power switch Q7 is connected with the other end of the third winding L3, and the second end is connected with the other end of the third energy storage unit C3, the anode of the third diode D3, the second end of the first module thyristor Q9, and the first end of the third winding thyristor Q8; one end of the fourth winding L4 is connected with the second end of the fourth winding thyristor Q5, the cathode of the third diode D3, and one end of the fourth energy storage unit C4; the first end of the fourth main power switch Q6 is connected with the other end of the fourth winding L4, and the second end is connected with the other end of the fourth energy storage unit C4, the second end of the third winding thyristor Q8, and the input ground end of the switching power supply. The control ends of the first module thyristors Q9 and Q10 are used for inputting the PWM signals with the same logic as the winding thyristors Q1, Q2, Q8, and Q5.

[0053] The secondary circuit is connected at both ends of the secondary winding of the transformer and includes rectifier diodes D4 and D5 and output filter capacitors C5 and C6. The secondary circuit is used to rectify and filter the energy transmitted by the transformer and output. In addition to the specific circuit shown in the figure, a secondary circuit using synchronous rectifier tubes for rectification can also be used to obtain higher efficiency. The specific rectification circuit is not limited in the embodiment. Figure 2

[0054] ​The working principle of the embodiment is as follows: when the switching power supply is started at a low voltage input, the PWM signal outputs a high level to drive the first module fill-gap tube Q9, the second module fill-gap tube Q10 and the winding fill-gap tubes Q1, Q2, Q8 and Q5 to be turned on, and the four main power winding switching circuits and the four energy storage units are in parallel connection; when the switching power supply is started at a high voltage input, the PWM signal outputs a low level to drive the first module fill-gap tube Q9, the second module fill-gap tube Q10 and the winding fill-gap tubes Q1, Q2, Q8 and Q5 to be turned off, and the four main power winding switching circuits and the four energy storage units are in series connection.

[0055] When the switching power supply is started at a low voltage input, the four main power winding switching circuits and the four energy storage units are in parallel connection, the total capacitance of the energy storage capacitors is increased, and sufficient energy can be provided under the condition of a lower input voltage to start the power supply; when the switching power supply is started at a high voltage input, the four main power winding switching circuits and the four energy storage units are in series connection, the voltage borne by a single energy storage capacitor and the stress of the switching tube are greatly reduced after being divided, and the voltage resistance of the whole switching power supply is improved, so the range of the input voltage can be widened.

[0056] In addition, the embodiment increases two windings on the basis of the original fill-gap circuit technology, and the first winding and the second winding are coupled to the same transformer T1, and the third winding and the fourth winding are coupled to the same transformer T2, so that the circuit can break through the original power limit and improve the output power while keeping the original transformer structure unchanged, or the power borne by the transformer can be halved while keeping the original output power unchanged, so that the transformer is designed to be ultra-thin and the cost is reduced.

[0057] Second embodiment

[0058] Figure 3 The principle diagram of the module fill-gap circuit described in the embodiment applied to the switching power supply is compared with the first embodiment, and the difference is that, in the embodiment, the first end of the second module fill-gap tube Q10 is connected to the first end of the second winding fill-gap tube Q2, and the second end of the first module fill-gap tube Q9 is connected to the second end of the third winding fill-gap tube Q8. The first PWM signal and the second PWM signal are not the same in logic.

[0059] The difference between the working principle of the embodiment and the first embodiment is that: the switching power supply can have an additional medium voltage input state by setting the first module valley filling tube Q9, Q10 and the winding valley filling tube Q1, Q2, Q8, Q5 with different logic PWM2 signals. When the switching power supply is started, the PWM signal output is low to drive the winding valley filling tube Q1, Q2, Q8, Q5 to turn off, at this time, the first and second main power winding switching circuits are in series, and the third and fourth main power winding switching circuits are also in series. The PWM2 signal output is high to drive the first module valley filling tube Q9, Q10 to turn on, at this time, the first valley filling sub-module circuit 100 and the second valley filling sub-module circuit 200 form a parallel relationship.

[0060] The medium voltage input energy storage circuit C1 and C2, C3 and C4 are in series, C1 and C2 are in parallel with C3 and C4, the total capacitance of the circuit is larger than that when the high voltage is input, and the voltage borne by each capacitor in the circuit is smaller than that when the low voltage is input, so it can adapt to the increased voltage in the middle of the input voltage range.

[0061] Third embodiment

[0062] Figure 4 The schematic diagram of the module valley filling circuit described in the embodiment applied to the switching power supply, compared with the first embodiment, the difference is that: in this embodiment, the series is expanded, a multi-stage module valley filling circuit is set, the module valley filling circuit increases the switching tube Qn1, Qn2, diode Dn1, Dn2, capacitor Cn1, Cn2, Cn3, winding Ln1, Ln2, Ln3, valley filling tube Qn3, Qn4, module valley filling tube Qn, Qnn, the principle of the multi-stage valley filling circuit is the same as that of the first and second embodiments, so it is not repeated here.

[0063] The above is only an embodiment of the utility model, it needs to be pointed out specially that the above embodiment should not be regarded as the limitation of the utility model, for ordinary skilled in the art, without departing from the spirit and scope of the utility model, can also make several improvements and refinements, these improvements and refinements should also be regarded as the protection scope of the utility model.

Claims

1. A modular valley-filling circuit, applied to a switching power supply, characterized in that: The module valley filling circuit comprises a first valley filling sub-module circuit, a second valley filling sub-module circuit, a first module valley filling tube, a second module valley filling tube and a first diode; The first end of the first valley filling sub-module circuit is connected to the first end of the first module valley filling tube, the second end of the first valley filling sub-module circuit is connected to the first end of the second module valley filling tube, and the third end of the first valley filling sub-module circuit is connected to the anode of the first diode; The first end of the second valley filling sub-module circuit is connected to the second end of the first module valley filling tube, the second end of the second valley filling sub-module circuit is connected to the second end of the second module valley filling tube, and the third end of the first valley filling sub-module circuit is connected to the cathode of the first diode; The control end of the first module valley filling tube and the control end of the second module valley filling tube are connected to a first PWM signal, the first module valley filling tube and the second module valley filling tube are used for controlling turn-on and turn-off according to the first PWM signal, thereby controlling the first valley filling sub-module circuit and the second valley filling sub-module circuit to be connected in parallel or in series.

2. The modular valley fill circuit of claim 1, wherein, The first valley filling sub-module circuit comprises a first main power winding switch circuit, a second main power winding switch circuit, a first energy storage unit, a second energy storage unit, a first winding valley filling tube, a second winding valley filling tube and a second diode; The first main power winding switch circuit comprises a first winding and a first main power switch tube, the first end of the first winding is connected to the first end of the first energy storage unit, the first end of the second winding valley filling tube and the positive input end of the switching power supply, the second end of the first winding is connected to the first end of the first main power switch tube, the second end of the first main power switch tube is connected to the second end of the first energy storage unit, the anode of the second diode and the first end of the first winding valley filling tube, and the control end of the first winding valley filling tube and the control end of the second winding valley filling tube are connected to a second PWM signal; The second main power winding switch circuit comprises a second winding and a second main power switch tube, the first end of the second winding is connected to the first end of the second energy storage unit, the cathode of the second diode and the second end of the second winding valley filling tube, the second end of the second winding is connected to the first end of the second main power switch tube, the second end of the second main power switch tube is connected to the second end of the second energy storage unit, the second end of the first winding valley filling tube and the anode of the first diode as the third end of the first valley filling sub-module circuit; The second end of the first winding valley filling tube is connected to the first end of the first module valley filling tube, and the first end of the second module valley filling tube is connected to the first end or the second end of the second winding valley filling tube.

3. The modular valley fill circuit of claim 2, wherein, The second valley filling sub-module circuit comprises a third main power winding switch circuit, a fourth main power winding switch circuit, a third energy storage unit, a fourth energy storage unit, a third winding valley filling tube, a fourth winding valley filling tube and a third diode; The third main power winding switch circuit comprises a third winding and a third main power switch tube, a first end of the third winding is connected with a first end of the third energy storage unit, a first end of the fourth winding tube, a cathode of the first diode, a second end of the third winding is connected with a first end of the third main power switch tube, a second end of the third main power switch tube is connected with a second end of the third energy storage unit, an anode of the third diode and a first end of the third winding tube, a control end of the third winding tube and a control end of the fourth winding tube are connected with a second PWM signal; The fourth main power winding switch circuit comprises a fourth winding and a fourth main power switch tube, a first end of the fourth winding is connected with a first end of the fourth energy storage unit, a cathode of the third diode, a second end of the fourth winding tube, a second end of the fourth winding is connected with a first end of the fourth main power switch tube, a second end of the fourth main power switch tube is connected with a second end of the fourth energy storage unit and a second end of the third winding tube; The first end of the fourth winding tube is connected to the second end of the second module tube, and the second end of the first module tube is connected to the first end or the second end of the third winding tube.

4. The modular valley fill circuit of claim 3, wherein, The first end of the second module tube is connected to the second end of the second winding tube, and the second end of the first module tube is connected to the first end of the third winding tube.

5. The modular valley fill circuit of claim 4, wherein, The first PWM signal and the second PWM signal are logically identical.

6. The modular valley fill circuit of claim 3, wherein, The first end of the second module tube is connected to the first end of the second winding tube, and the second end of the first module tube is connected to the second end of the third winding tube.

7. A modular valley fill circuit according to claim 6, wherein, The first PWM signal and the second PWM signal are not logically identical.

8. The modular valley fill circuit of claim 2, wherein, The first winding and the second winding are coupled to the same transformer.

9. The modular valley fill circuit of claim 3, wherein, The third winding and the fourth winding are coupled to the same transformer.

10. A switching power supply characterized by comprising: The switching power supply comprises a module tube circuit as claimed in any one of claims 1-9.

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