CN113300609B - Single-IC (integrated circuit) driven multi-path single-stage PFC (power factor correction) parallel circuit and working method thereof - Google Patents

Abstract

The embodiment of the invention discloses a single-IC-driven multi-path single-stage PFC parallel circuit and a working method thereof, the circuit comprises a control unit, a main power loop unit, a current detection unit and a balance unit, wherein the main power loop unit comprises a plurality of transformers, the transformers are provided with secondary output ends and primary input ends, the secondary output ends of the transformers are connected with rectifier diodes, one ends of the primary input ends of the transformers are connected with a bus, the other ends of the primary input ends of the transformers are respectively connected with Mos tubes, grids of the Mos tubes are respectively connected with the control unit, and sources of the Mos tubes are connected with the current detection unit; the drain electrodes of the Mos tubes are respectively connected with the balancing unit; and the balancing unit coordinates the consistency of the sub-power loop signals of the transformers. The embodiment of the invention simplifies the circuit, saves the manufacturing cost and expands the application power range of the single-stage flyback topology; and the magnetic integrated transformer is combined, so that the size is reduced and the efficiency is improved.

Description

Single-IC-driven multi-path single-stage PFC parallel circuit and working method thereof

Technical Field

The invention relates to the technical field of single-stage PFC driving circuits, in particular to a multi-path single-stage PFC parallel circuit driven by a single IC and a working method thereof.

Background

With the popularization of the LED lighting technology in road lighting, the design of the driving Power supply is thoroughly mature, how to keep enough competitiveness in the completely competitive market status becomes the top topic of attention of various Power supply manufacturers, in the field of road lighting with low requirements for light quality in the past, a single-stage PFC (Power Factor Correction) topology provides a cheap choice, but because of the reason that the current stress of a switching device is too large and the transformer process is difficult to overcome, the single-stage PFC flyback itself limits the application in a medium-high Power section such as 100W-300W Power section, and therefore, the multiple single-stage independent PFC flyback circuits are connected in parallel, because each unit is completely independent, with the increase of the number of circuits, additional multiplication costs such as IC, power supply winding and peripheral voltage stabilization, detection and the like are inevitably generated, and the cost is high. And when the number of independent loops is increased to more than 2, extremely strong disturbance exists between the loops, and the stability of the driving power supply is influenced.

Therefore, it is necessary to design a new circuit, which can simplify the circuit and save the cost.

Disclosure of Invention

The invention aims to solve the technical problem of providing a multi-path single-stage PFC parallel circuit driven by a single IC and a working method thereof.

In order to solve the technical problems, the invention aims to realize the following technical scheme: the method comprises the steps that a single-IC-driven multi-path single-stage PFC parallel circuit is provided and comprises a control unit, a main power loop unit, a current detection unit and a balance unit, wherein the main power loop unit comprises a plurality of transformers, each transformer is provided with a secondary output end and a primary input end, the secondary output ends of the plurality of transformers are connected with rectifier diodes, one ends of the primary input ends of the plurality of transformers are connected with a bus, the other ends of the primary input ends of the plurality of transformers are respectively connected with Mos tubes, grid electrodes of the plurality of Mos tubes are respectively connected with the control unit, and source electrodes of the plurality of Mos tubes are respectively connected with the current detection unit; the drain electrodes of the Mos tubes are respectively connected with the balancing unit; the main power loop unit is used for switching on and switching off the Mos tube under the driving of the control unit and realizing energy conversion through the transformer; the current detection unit is used for detecting a current signal of the source electrode of the Mos tube and supplying the current signal to the control unit; and the balancing unit is used for coordinating the consistency of the sub-power loop signals where the transformers are located.

The further technical scheme is as follows: the voltage detection unit is connected with the control unit; the voltage detection unit is used for detecting an output voltage signal and providing the output voltage signal to the control unit; the voltage detection unit comprises auxiliary windings and a resistor divider of one of the transformers.

The further technical scheme is as follows: the balancing unit includes a balancing resistor.

The further technical scheme is as follows: the current detection unit includes a detection resistor R13.

The further technical scheme is as follows: the rectifier and filter unit comprises a rectifier bridge stack and a noise filtering element which are sequentially connected, the input end of the rectifier and filter unit is connected with an alternating current power supply, and the output end of the rectifier and filter unit is connected with a bus.

The further technical scheme is as follows: the device also comprises a totem current-expanding driving unit which is respectively connected with the control unit and the grid electrode of the Mos tube.

The further technical scheme is as follows: the totem-pole current-expanding driving unit comprises a first switching element.

The further technical scheme is as follows: the first switching element comprises a triode Q3, the base electrode of the triode Q3 is connected with the control unit, and the emitting electrode of the triode Q3 is connected with the grid electrode of the Mos tube; and a driving resistor is also connected between the emitting electrode of the triode Q3 and the grid electrode of the Mos tube.

The further technical scheme is as follows: the device also comprises a power supply unit; the power supply unit is connected with the bus through a starting resistor; the power supply unit is connected with an auxiliary winding of one of the transformers.

In addition, the technical problem to be solved by the present invention is to provide a working method for driving a multi-path single-stage PFC parallel circuit by a single IC, comprising:

when the control unit drives the Mos tube in the main power loop unit to be turned off, the plurality of transformers form an equivalent transformer, current at the primary input ends of the plurality of transformers is collected by the current detection unit and input to the control unit, when the Mos tube is turned off, the transformers are reversely excited to transmit energy to the secondary output end, the balancing unit is connected with the transformers to maintain energy flow to coordinate and balance each path of the transformers to maintain an approximately synchronous quasi-resonance state, and the transformers enter the next state after the energy is released.

Compared with the prior art, the invention has the beneficial effects that: the invention expands the power range and the application field of single-stage flyback PFC topology by arranging the control unit, the main power loop unit, the current detection unit and the balance unit, simplifies the circuit design and saves the manufacturing cost, the same current detection unit is adopted in the main power loop unit for current detection, all Mos tubes have the same conduction time and conduction time under the control of the same control unit, the consistency and the effectiveness of current signals are ensured, the balance unit is adopted to coordinate the states of all sub-loops, the consistency and the effectiveness of voltage signals are ensured, the multipath design can allow no need of a very large transformer and a high-power Mos tube, only a relatively small transformer allowed by the process and a more easily obtained common Mos tube are needed, the problem of shunting balance of the Mos tubes is not needed to be considered, and the invention has wide application prospect; the unique strict synchronism of the circuit allows the use of a magnetically integrated transformer, effectively improving efficiency and reducing volume.

The invention is further described below with reference to the figures and the specific embodiments.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic block diagram of a multi-path single-stage PFC parallel circuit driven by a single IC according to an embodiment of the present invention;

fig. 2 is a specific circuit schematic diagram of a multi-path single-stage PFC parallel circuit driven by a single IC according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of an E-I-E type transformer for magnetic integration according to an embodiment of the present invention.

Fig. 4 is a schematic diagram of connection of the balancing unit when three or more single-stage PFCs are connected in parallel according to an embodiment of the present invention.

The labels in the figures illustrate:

10. a control unit; 20. a main power loop unit; 30. a current detection unit; 40. a balancing unit; 50. a totem spread-current drive unit; 60. a power supply unit; 70. a voltage detection unit; 80. and a rectification filtering unit.

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 some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

Referring to fig. 1, fig. 1 is a schematic block diagram of a multi-path single-stage PFC parallel circuit driven by a single IC according to an embodiment of the present invention. Because the circuit has strict synchronism, the circuit is particularly suitable for a magnetic integrated transformer. The embodiment of the invention exemplifies an E-I-E type transformer as shown in fig. 3, and other similar applications of the magnetic integration method are within the scope of the invention. Assuming that two independent EI transformers are needed in normal use, wherein the thickness of an I sheet is the same as that of the upper transverse part of an E sheet; when the magnetic integration technology is used, the two transformers are respectively wound on the upper core column and the lower core column, and the winding directions of all corresponding windings are the same, because the magnetic chains passing through the I pieces are opposite and mutually offset, only the thin I piece meeting the mechanical strength is needed in the middle, and the unbalanced magnetic chains of the two windings are allowed to pass through. The magnetic loss of the part of the I piece and the length of the transformer equivalent to the thickness of two I pieces are greatly reduced, the economic effect is obvious, more magnetic integrated transformers can be overlapped according to the thought, and the windings of the transformer can be wound synchronously along with the popularization of an automatic winding technology, so that the process is greatly simplified and the labor is saved while the consistency of all the windings is ensured.

The single IC drives the multi-path single-stage PFC to be connected in parallel, and the consistency and the effectiveness of sampling of various key electric signals such as voltage and current are required to be ensured. Because the sampling signals of different single-stage circuits are asynchronous due to the influence of the working conditions and self errors of each path of element and the temperature of the element, particularly the difference of VF (variable frequency) of a secondary diode under the influence of the temperature, all the circuits cannot be represented by one path of signal. To solve this problem, all circuits must be connected; one option is to directly connect all corresponding windings in parallel, but the resulting circulating current loss and EMI (Electromagnetic Interference) problems and the difficulty of actual board layout increase, which make the option less easy to implement, especially in more than two independent power loops; the multi-loop parallel technology adopted by the embodiment is convenient for realizing that a single IC drives a multi-path single-stage PFC.

Referring to fig. 1, the multi-path single-stage PFC parallel circuit driven by the single IC includes a control unit 10, a main power loop unit 20, a current detection unit 30, and a balance unit 40; the main power loop unit 20 comprises a plurality of transformers, each transformer is provided with a secondary output end and a primary input end, the secondary output ends of the plurality of transformers are connected with rectifier diodes, one ends of the primary input ends of the plurality of transformers are connected with a bus, the other ends of the primary input ends of the plurality of transformers are respectively connected with Mos tubes, grids of the plurality of Mos tubes are respectively connected with the control unit 10, and sources of the plurality of Mos tubes are connected with the current detection unit 30; the drain electrodes of the Mos tubes are respectively connected with a balancing unit 40; the main power loop unit 20 is used for switching on and off the Mos tube under the driving of the control unit, and realizing energy conversion through the transformers, specifically, outputting energy to a secondary side through a plurality of transformers; a current detection unit 30 for detecting a current signal of the source of the Mos transistor and supplying the current signal to the control unit; the balancing unit 40 is used for coordinating the consistency of the sub-power loop signals where the transformers are located; specifically, the balancing unit 40 is configured to connect the transformers to maintain weak energy flow to coordinate each of the transformers to maintain a quasi-resonant state that is approximately synchronous, and enter a next state after all the transformers have released energy.

Referring to fig. 2, fig. 2 is a schematic diagram of a specific circuit of a single IC driven multi-path single-stage PFC parallel circuit according to an embodiment of the present invention, which specifically shows a case of parallel connection of two single-stage PFCs, where the embodiment provides parallel connection of two transformers, a plurality of transformers include a transformer T1 and a transformer T2, a secondary output terminal of the transformer T1 and a secondary output terminal of the transformer T2 are connected in parallel after passing through respective rectifier diodes, the Mos tube includes a Mos tube Q1 and a Mos tube Q6, a primary input terminal of the transformer T1 is connected to a drain electrode of the Mos tube Q1, a primary input terminal of the transformer T2 is connected to a drain electrode of the Mos tube Q6, specifically, a rectifier diode D4, a peak absorption capacitor C2 and a leakage resistor R5 are further connected between the drain electrode of the Mos tube Q1 and the primary input terminal of the transformer T1, and a rectifier diode D3, a peak absorption capacitor C3 and a leakage resistor R6 are further connected between the drain electrode of the Mos tube Q6 and the primary input terminal of the transformer T2.

In one embodiment, the balancing unit 40 includes a balancing resistor.

In this embodiment, referring to fig. 2, the balancing resistor includes a resistor R7, one end of the resistor R7 is connected between the rectifying diode D4 and the drain of the Mos transistor Q1, and the other end of the resistor R7 is connected between the rectifying diode D3 and the drain of the Mos transistor Q6.

In an embodiment, referring to fig. 2, the current detection unit 30 includes a detection resistor R13.

Each circuit in the main power circuit unit 20 is relatively independent, each circuit has an independent transformer, mos tube, rectifier diode and smoothing electrolytic capacitor, and is only combined and connected in parallel at the secondary output, the primary side is connected through the balancing unit 40 and a resistor R7, and all current flows through the common detection resistor R13 (current detection unit 30). All units share one voltage detection unit 70, one power supply unit 60 and the rectification filtering unit 80, so that the parallel connection of the previous independent circuits is greatly simplified. When the main power loop unit 20 is composed of more than 2 sub-units, only the resistance of the balancing unit 40 needs to be increased, for example, to 3 sub-units, as shown in fig. 4, the connection method is that 3 resistors are respectively connected to the drains of 3 Mos tubes, and the other ends of the resistors are connected together to form a star connection method. The principle is that, in order to ensure the uniformity of signals, circuits need to be connected with each other by means of the balancing unit 40, after one path of energy is flyback-released, the other path of energy can provide certain energy to the balancing unit 40, and the existence of the resistor R7 limits the size of a circulating current, so that only weak energy is provided to the previous unit with the completed energy release to maintain the flyback state, and the other paths wait for the completion of flyback energy release.

In addition, referring to fig. 2, the current detecting unit 30 further includes a filter resistor R13 and a filter capacitor C7, wherein one end of the filter capacitor C7 is grounded, and the other end is connected between the detecting resistor R13 and the control unit 10, so as to perform a filtering function.

The multi-path design can allow no need of a very large transformer and a high-power Mos tube, only a relatively small transformer allowed by the process and a common Mos tube which is easy to obtain are needed, the shunting balance problem of the Mos tube is not needed to be considered, and the method has a wide application prospect; the strict synchronism of the circuit specially allows the use of a magnetic integrated transformer, effectively improves the efficiency and reduces the volume.

In an embodiment, referring to fig. 1, the single IC driving multi-path single-stage PFC parallel circuit further includes a totem-pole current spreading driving unit 50, and the totem-pole current spreading driving unit 50 is respectively connected to the control unit 10 and the gate of the Mos transistor.

The single control unit 10 cannot drive a plurality of Mos tubes, and the Mos tubes of a plurality of independent loops are simultaneously driven after current is expanded by the totem current expansion driving unit 50.

In an embodiment, the totem-pole current spreading driving unit 50 includes a first switching element.

Specifically, referring to fig. 2, the first switching element includes a transistor Q3, a base of the transistor Q3 is connected to the control unit 10, and an emitter of the transistor Q3 is connected to a gate of the Mos transistor.

In addition, a driving resistor is connected between the emitter of the triode Q3 and the gate of the Mos transistor.

A resistor R8 is connected between the base of the triode Q3 and the control unit 10, the collector of the triode Q3 is connected with a power supply, the driving resistor comprises resistors R5, R11, R10 and R9, wherein the resistor R5 is connected with the resistor R11, and the resistor R11 is connected with the grid of the Mos tube Q1; the resistor R10 is connected with the resistor R9, and the resistor R9 is connected with the grid electrode of the Mos tube Q6.

In addition, the totem-pole current-spreading driving unit 50 further includes a transistor Q2 and a transistor Q5, an emitter of the transistor Q2 is connected to the resistor R5, and a collector of the transistor Q2 is connected to the detection resistor R13; an emitting electrode of the triode Q5 is connected with the resistor R10, and a collecting electrode of the triode Q5 is connected with the detection resistor R13; the base electrode of the triode Q2 and the base electrode of the triode Q5 are respectively connected with the control unit 10.

In an embodiment, referring to fig. 1, the multi-path single-stage PFC parallel circuit driven by a single IC further includes a power supply unit 60 and a voltage detection unit 70, wherein the power supply unit 60 is connected to a bus through a starting resistor R4, and the power supply unit is connected to an auxiliary winding of one of the transformers. In the present embodiment, the input side of the power supply unit 60 is connected to the auxiliary winding of the transformer T1.

In an embodiment, referring to fig. 1, the multi-stage PFC parallel circuit further includes a voltage detection unit 70. The voltage detection unit 70 is connected with the control unit 10, and the voltage detection unit 70 is used for detecting an output voltage signal and providing the output voltage signal to the control unit 20; the voltage detecting unit 70 includes an auxiliary winding and a resistor divider of one of the transformers, in this embodiment, the voltage detecting unit 70 is connected to the auxiliary winding of the transformer T1, but is not limited to the auxiliary winding of the transformer T1, and may be a corresponding winding of any one of the transformers, such as T2B.

In this embodiment, referring to fig. 2, the voltage detecting unit 70 includes a voltage sampling resistor R1, one end of the voltage sampling resistor R1 is connected to the auxiliary winding, and the other end is connected to a resistor R2 and a capacitor C1 which are connected in parallel; the other end of the resistor R2 and the capacitor C1 which are connected in parallel is connected with a signal ground.

In this embodiment, referring to fig. 2, the power supply unit 60 includes a transistor Q9 connected to a power supply, a diode D2 is connected between an emitter of the transistor Q9 and the power supply, a resistor R4 is connected between the power supply and a primary input end of the transformer, the power supply is further connected to an electrolytic capacitor EC2, a base of the transistor Q9 is further connected to a voltage stabilizing diode ZD1, an electrolytic capacitor EC1 is connected in parallel between a collector of the transistor Q9 and a signal ground, a resistor R3 is connected between the collector of the transistor Q9 and the base, the collector of the transistor Q9 is connected to a diode D1, and the diode D1 is further connected to an auxiliary winding T1B of the transformer T1. The diode D1 may also be connected to the auxiliary winding T2B of the transformer T2, which may be freely selected according to the convenience of wiring. The power supply unit 60 functions as a start-up and linear regulated power supply.

In an embodiment, referring to fig. 1, the multi-path single-stage PFC parallel circuit driven by the single IC further includes a rectifying and filtering unit 80, the rectifying and filtering unit 80 includes a rectifying bridge stack and a noise filtering element connected in sequence, an input end of the rectifying and filtering unit 80 is connected to an ac power source, and an output end of the rectifying and filtering unit 80 is connected to a bus.

The rectifying and filtering unit 80 may be, but is not limited to, a rectifying filter.

In an embodiment, referring to fig. 2, the control unit 10 includes a main control chip U1, and the model of the main control chip U1 is SY5882A, but is not limited to SY5882A.

There are two key signals for a single stage PFC: the voltage feedback signal reflects the flyback time length except controlling the overvoltage point and controls the output current together with the current feedback signal; the current feedback signal, namely the current signal flowing in the main loop, and the voltage signal control the output current together; the parallel connection of the multi-path single-stage PFC means that a plurality of power loops are provided, and the power loops comprise independent transformers, mos tubes, rectifier diodes and capacitors, wherein the capacitors are actually connected in parallel. Although the control process of a plurality of power loops is adopted, only one control chip is used, and the sampled signals can represent the working states of all the power loops; a plurality of transformers are connected in parallel to form an equivalent transformer, and the equivalent inductance is the parallel connection of primary inductances of the transformers; sources of Mos tubes of all loops are connected together and share the same sampling resistor, so that the effectiveness of current signals is guaranteed; when the flyback operation is completed, the existence of the balancing unit 40 ensures the consistency and effectiveness of the voltage signal, and the same control unit 10 controls the voltage signal to have the same conduction time and conduction time, so that the consistency of the current signal is ensured.

The working principle of the whole circuit is as follows:

when the main control chip U1 sends a driving signal, the current is first expanded through the totem current expansion driving unit 50, and the Mos tubes on the primary side of each independent loop are simultaneously driven, because the loops where each transformer is located are independent, the situation of uneven current distribution does not exist. And similarly, synchronously switching off each Mos tube through the lower tube of the totem pole during switching off. Because the switching time is synchronous, the transformers of each loop are equivalent to an equivalent transformer together, the primary inductance of each equivalent transformer is formed by connecting the primary inductances of the discrete transformers in parallel, and the primary currents of the transformers are collected together and are acquired through the same detection resistor R13, so that the acquisition of the primary currents of the equivalent transformers is equivalent to the acquisition of the primary currents of the equivalent transformers; when the Mos tube is turned off, a loop where each transformer is located starts flyback to transmit energy to a secondary, the flyback maintaining time of each transformer is different due to the difference of elements including the inductance of the transformer, the voltage drop VF of the diode and the influence of temperatures at different positions, if the flyback maintaining time is not controlled, part of loops can release energy in advance to enter the next state, the balancing unit 40 starts to play a role at the moment, and the unit which does not complete energy release can provide part of energy to the finished unit to maintain the state through the interconnection of the balancing unit 40 and wait for all the units to release energy; at the same time, the presence of the balancing unit 40 limits the amount of power supplied, preventing the formation of large circulating currents with unnecessary losses and the generation of possible oscillations. After the energy release of all the units is completed, the units start to enter the next working state in a lockstep manner, so that the consistency of the voltage sampling signals is ensured.

All sub-power circuits have strict synchronicity and several transformers can be magnetically integrated in a specific way, as shown in fig. 3, further reducing the volume and increasing the efficiency.

According to the single IC driving circuit of the multi-path single-stage PFC, the control unit 10, the main power loop unit 20, the current detection unit 30 and the balance unit 40 are arranged, the power range and the application field of a single-stage flyback PFC topology are expanded, the circuit design is simplified, the manufacturing cost is saved, the same current detection unit 30 is adopted in the main power loop unit 20 for current detection, all the Mos tubes have the same conduction time and conduction time under the control of the same control unit 10, the consistency and the effectiveness of current signals are ensured, the balance unit 40 is adopted to coordinate the states of the sub-loops, the balance unit 40 is adopted to balance the flyback capability, the consistency and the effectiveness of voltage signals are ensured, the multi-path design can allow no large transformer and large power Mos tubes, only relatively small transformers allowed by the process and common Mos tubes which are easy to obtain are needed, the shunt balance problem of the Mos tubes is not needed to be considered, and the single IC driving circuit has a wide application prospect; the unique strict synchronism of the circuit allows the use of a magnetically integrated transformer, effectively improving efficiency and reducing volume.

It should be noted that, as can be clearly understood by those skilled in the art, the specific implementation process of the working method of the single IC driving circuit of the multi-path single-stage PFC described above may refer to the corresponding description in the embodiment of the single IC driving circuit of the multi-path single-stage PFC, and for convenience and brevity of description, details are not repeated herein.

While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (7)

1. The single-IC-driven multi-path single-stage PFC parallel circuit is characterized by comprising a control unit, a main power loop unit, a current detection unit and a balance unit, wherein the main power loop unit comprises a plurality of transformers, each transformer is provided with a secondary output end and a primary input end, the secondary output ends of the plurality of transformers are connected with rectifier diodes, one ends of the primary input ends of the plurality of transformers are connected with a bus, the other ends of the primary input ends of the plurality of transformers are respectively connected with Mos tubes, grid electrodes of the plurality of Mos tubes are respectively connected with the control unit, and source electrodes of the plurality of Mos tubes are respectively connected with the current detection unit; the drain electrodes of the Mos tubes are respectively connected with the balancing unit; the main power loop unit is used for switching on and switching off the Mos tube under the driving of the control unit and realizing energy conversion through the transformer; the current detection unit is used for detecting a current signal of the source electrode of the Mos tube and providing the current signal to the control unit; the balancing unit is used for coordinating the consistency of the sub-power loop signals where the transformers are located; the voltage detection unit is connected with the control unit; the voltage detection unit is used for detecting an output voltage signal and providing the output voltage signal to the control unit; the voltage detection unit comprises auxiliary windings and a resistance voltage divider of one of the plurality of transformers; the balancing unit comprises a balancing resistor; the current detection unit comprises a detection resistor R13;

each loop in the main power loop unit is relatively independent, each loop is provided with an independent transformer, a Mos tube, a rectifier diode and a flat wave electrolytic capacitor, the circuits are only converged and connected in parallel at the output of the secondary, the primary side is connected through a balancing unit and a resistor R7, all currents flow through a common detection resistor R13, all the units share one voltage detection unit, one power supply unit and a rectification filtering unit, and when the main power loop unit is composed of more than 2 sub-units, only the resistance of the balancing unit needs to be increased.

2. The single-IC-driven multi-path single-stage PFC parallel circuit as claimed in claim 1, further comprising the rectifying and filtering unit, wherein the rectifying and filtering unit comprises a rectifying bridge stack and a noise filtering element which are sequentially connected, an input end of the rectifying and filtering unit is connected with an alternating current power supply, and an output end of the rectifying and filtering unit is connected with a bus.

3. The single-IC-driven multi-path single-stage PFC parallel circuit as claimed in claim 1, further comprising a totem-pole driver unit, wherein the totem-pole driver unit is respectively connected with the control unit and a gate of the Mos tube.

4. The single-IC driven multi-way single-stage PFC parallel circuit of claim 3, wherein the totem-pole current-spreading driving unit comprises a first switching element.

5. The single-IC driven multi-stage single-stage PFC parallel circuit according to claim 4, wherein the first switching element comprises a transistor Q3, a base of the transistor Q3 is connected with the control unit, and an emitter of the transistor Q3 is connected with a gate of the Mos transistor; and a driving resistor is also connected between the emitting electrode of the triode Q3 and the grid electrode of the Mos tube.

6. The single-IC driven multi-path single-stage PFC parallel circuit of claim 1, further comprising a power supply unit; the power supply unit is connected with the bus through a starting resistor; the power supply unit is connected with an auxiliary winding of one of the transformers.

7. An operating method of a single-IC-driven multi-single-stage PFC parallel circuit, wherein the operating method uses the single-IC-driven multi-single-stage PFC parallel circuit of any one of claims 1 to 6, and comprises the following steps:

when the control unit drives the Mos tube in the main power loop unit to be turned off, the plurality of transformers form an equivalent transformer, current at the primary input ends of the plurality of transformers is collected by the current detection unit and input to the control unit, when the Mos tube is turned off, the transformers are reversely excited to transmit energy to the secondary output end, the balancing unit is connected with the transformers to maintain energy flow to coordinate and balance each path of the transformers to maintain an approximately synchronous quasi-resonance state, and the transformers enter the next state after the energy is released.

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