阅读说明：本技术 Llc输出大电流的整流控制电路及开关电源 (Rectification control circuit for LLC (logical Link control) output large current and switching power supply ) 是由 梁加开 于 2021-01-29 设计创作，主要内容包括：本发明公开了一种LLC输出大电流的整流控制电路及开关电源,电路包括第一原边开关模块、第二原边开关模块、变压器、第一副边MOS管、第二副边MOS管、第一电感、第二电感和输出电容；第一原边开关模块的输出端接第二原边开关模块的输入端和变压器的初级绕组,第二原边开关模块的输出端和变压器的初级绕组接地；变压器的次级绕组的第一端接第一电感的第一端和第二副边MOS管,变压器的次级绕组的第二端接第二电感的第一端和第一副边MOS管,第一副边MOS管接第一电感的第一端,第二副边MOS管接第二电感,第一副边MOS管和第二副边MOS管输出电容,第一电感和第二电感接输出电容。本方案使流经输出电容的电流始终都是2路电流,改善输出电容的纹波电流问题。(The invention discloses a rectification control circuit and a switching power supply for LLC (logical link control) output large current, wherein the circuit comprises a first primary side switch module, a second primary side switch module, a transformer, a first secondary side MOS (metal oxide semiconductor) transistor, a second secondary side MOS transistor, a first inductor, a second inductor and an output capacitor; the output end of the first primary side switch module is connected with the input end of the second primary side switch module and the primary winding of the transformer, and the output end of the second primary side switch module and the primary winding of the transformer are grounded; the first end of the secondary winding of the transformer is connected with the first end of the first inductor and the second secondary side MOS tube, the second end of the secondary winding of the transformer is connected with the first end of the second inductor and the first secondary side MOS tube, the first secondary side MOS tube is connected with the first end of the first inductor, the second secondary side MOS tube is connected with the second inductor, the first secondary side MOS tube and the second secondary side MOS tube output capacitors, and the first inductor and the second inductor are connected with the output capacitors. The scheme ensures that the current flowing through the output capacitor is 2 paths of current all the time, and improves the problem of ripple current of the output capacitor.)

1. A rectification control circuit of LLC output large current is characterized by comprising a first primary side switch module, a second primary side switch module, a transformer, a first secondary side MOS (metal oxide semiconductor) tube, a second secondary side MOS tube, a first inductor, a second inductor and an output capacitor; the input end of the first primary side switch module is connected with the power input, the output end of the first primary side switch module is connected with the input end of the second primary side switch module and the first end of the primary winding of the transformer, and the output end of the second primary side switch module and the second end of the primary winding of the transformer are grounded;

the first termination of the secondary winding of transformer connects the first end of first inductance with the G utmost point of the vice limit MOS pipe of second, the second termination of the secondary winding of transformer the first end of second inductance with the G utmost point of first vice limit MOS pipe, the D utmost point of first vice limit MOS pipe connects the first end of first inductance, the D utmost point of the vice limit MOS pipe of second connects the first end of second inductance, the S utmost point of first vice limit MOS pipe and the vice limit MOS pipe of second connects output capacitance 'S negative pole, the second termination of first inductance and second inductance output capacitance' S anodal output.

2. The LLC high-current output rectification control circuit according to claim 1, wherein said first primary side switch module comprises a first primary side MOS transistor, a first triode, a first resistor, a second resistor and a third resistor; the power input is connected with the D pole of the first primary side MOS tube, the G pole of the first primary side MOS tube is connected with the first ends of the first resistor and the second resistor, the second end of the first resistor is connected with the e pole of the first triode and the first end of the third resistor, the b pole of the first triode is connected with the second end of the third resistor and the first control end pin, and the c pole of the first triode and the second end of the second resistor are connected with the first end of the primary winding of the transformer.

3. The LLC high-current output rectification control circuit according to claim 2, wherein said second primary side switch module comprises a second primary side MOS transistor, a second triode, a fourth resistor, a fifth resistor and a sixth resistor; the D pole of the second primary side MOS tube is connected with the first end of the primary winding of the transformer, the G pole of the second primary side MOS tube is connected with the first ends of a fourth resistor and a fifth resistor, the second end of the fourth resistor is connected with the e pole of a second triode and the first end of a sixth resistor, the b pole of the second triode is connected with the second end and the second control terminal pin of the sixth resistor, and the c pole of the second triode, the second end of the fifth resistor and the S pole of the second primary side MOS tube are grounded.

4. The rectification control circuit of LLC output large current according to claim 1, further comprising a first secondary capacitor, a seventh resistor and an eighth resistor, wherein a first end of said first secondary capacitor is connected to a second end of the secondary winding of said transformer, a second end of said first secondary capacitor is connected to a first end of said seventh resistor, second ends of said seventh resistor and said eighth resistor are connected to a G pole of said first secondary MOS transistor, and a first end of said eighth resistor is connected to an S pole of said first secondary MOS transistor.

5. The rectification control circuit of LLC large current according to claim 1, further comprising a second secondary capacitor, a ninth resistor and a tenth resistor, wherein a first end of said second secondary capacitor is connected to a first end of the secondary winding of said transformer, a second end of said second secondary capacitor is connected to a first end of said ninth resistor, second ends of said ninth resistor and said tenth resistor are connected to a G pole of said second secondary MOS transistor, and a first end of said tenth resistor is connected to an S pole of said second secondary MOS transistor.

6. The LLC high current output rectification control circuit according to claim 1, wherein said first inductor and said second inductor are both energy storage inductors.

7. The LLC high-current-output rectification control circuit of claim 1, further comprising an input capacitor, wherein an anode of said input capacitor is connected to the input terminal of said first primary-side switch module, and a cathode of said input capacitor is connected to ground.

8. The rectification control circuit for LLC high current output according to claim 1, further comprising a filter capacitor, wherein a first end of said filter capacitor is connected to a second end of the primary winding of said transformer, and a second end of said filter capacitor is connected to ground.

9. The LLC high current output rectification control circuit according to claim 1, wherein said output capacitor is an electrolytic capacitor.

10. A switching power supply comprising an LLC current-out rectifier control circuit as claimed in any one of claims 1-9.

Technical Field

The invention relates to the field of rectification circuits, in particular to a rectification control circuit for LLC (logical link control) output large current and a switching power supply.

Background

LLC is a resonant circuit, which contains inductance, capacitance and resistance elements, and can achieve resonance with constant output voltage by controlling the switching frequency (frequency regulation), with the advantage that the switching loss of the power supply can be reduced and the efficiency and power density of the power converter can be improved by soft switching techniques.

The existing LLC topology circuit can be used in large quantity due to the high working efficiency of the soft switch, but the topology has the defect that the ripple current proportion of an output capacitor is very large and is 0.48 times of the output current theoretically. When the output current is larger, the defects of the LLC topology circuit are more obvious, and the volume, the cost and the service life of the output capacitor become the defects of the LLC topology circuit.

Therefore, it is necessary to provide a rectification control circuit for the LLC to output a large current.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a rectification control circuit and a switching power supply for LLC (logical link control) output large current.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the invention provides a rectification control circuit for outputting a large current by an LLC, comprising a first primary side switch module, a second primary side switch module, a transformer, a first secondary side MOS transistor, a second secondary side MOS transistor, a first inductor, a second inductor, and an output capacitor; the input end of the first primary side switch module is connected with the power input, the output end of the first primary side switch module is connected with the input end of the second primary side switch module and the first end of the primary winding of the transformer, and the output end of the second primary side switch module and the second end of the primary winding of the transformer are grounded;

the first termination of the secondary winding of transformer connects the first end of first inductance with the G utmost point of the vice limit MOS pipe of second, the second termination of the secondary winding of transformer the first end of second inductance with the G utmost point of first vice limit MOS pipe, the D utmost point of first vice limit MOS pipe connects the first end of first inductance, the D utmost point of the vice limit MOS pipe of second connects the first end of second inductance, the S utmost point of the vice limit MOS pipe of first vice limit and second meets output capacitance 'S negative pole, the second termination of first inductance and second inductance output capacitance' S positive output.

Further, the first primary side switch module comprises a first primary side MOS transistor, a first triode, a first resistor, a second resistor, and a third resistor; the power input is connected with the D pole of the first primary side MOS tube, the G pole of the first primary side MOS tube is connected with the first ends of the first resistor and the second resistor, the second end of the first resistor is connected with the e pole of the first triode and the first end of the third resistor, the b pole of the first triode is connected with the second end of the third resistor and the first control end pin, and the c pole of the first triode and the second end of the second resistor are connected with the first end of the primary winding of the transformer.

Further, the second primary side switch module comprises a second primary side MOS transistor, a second triode, a fourth resistor, a fifth resistor, and a sixth resistor; the D pole of the second primary side MOS tube is connected with the first end of the primary winding of the transformer, the G pole of the second primary side MOS tube is connected with the first ends of a fourth resistor and a fifth resistor, the second end of the fourth resistor is connected with the e pole of a second triode and the first end of a sixth resistor, the b pole of the second triode is connected with the second end and the second control terminal pin of the sixth resistor, and the c pole of the second triode, the second end of the fifth resistor and the S pole of the second primary side MOS tube are grounded.

The transformer further comprises a first secondary capacitor, a seventh resistor and an eighth resistor, wherein the first end of the first secondary capacitor is connected with the second end of the secondary winding of the transformer, the second end of the first secondary capacitor is connected with the first end of the seventh resistor, the second ends of the seventh resistor and the eighth resistor are connected with the G pole of the first secondary MOS tube, and the first end of the eighth resistor is connected with the S pole of the first secondary MOS tube.

Further, the transformer further comprises a second secondary side capacitor, a ninth resistor and a tenth resistor, wherein the first end of the second secondary side capacitor is connected with the first end of the secondary winding of the transformer, the second end of the second secondary side capacitor is connected with the first end of the ninth resistor, the second ends of the ninth resistor and the tenth resistor are connected with the G pole of the second secondary side MOS tube, and the first end of the tenth resistor is connected with the S pole of the second secondary side MOS tube.

Further, the first inductor and the second inductor are both energy storage inductors.

The input capacitor is connected with the input end of the first primary side switch module through a positive electrode, and the negative electrode of the input capacitor is grounded.

Furthermore, the transformer further comprises a filter capacitor, wherein the first end of the filter capacitor is connected with the second end of the primary winding of the transformer, and the second end of the filter capacitor is grounded.

Further, the output capacitor is an electrolytic capacitor.

In a second aspect, the present invention further provides a switching power supply, including the LLC high-current-output rectification control circuit as described in any one of the above.

Compared with the prior art, the invention has the beneficial effects that: according to the rectification control circuit and the switching power supply for the LLC to output the large current, the first primary side switch module and the second primary side switch module are alternately conducted, and the first secondary side MOS tube and the second secondary side MOS tube on the secondary side of the transformer are alternately and complementarily conducted, so that the current flowing through the output capacitor is always 2 paths of current, the problem of ripple current of the output capacitor is solved, and the soft switching characteristic of the LLC is ensured.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented according to the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more apparent, the following detailed description will be given of preferred embodiments.

Drawings

FIG. 1 is a circuit diagram of a rectification control circuit of an LLC output large current according to an embodiment of the invention;

fig. 2 is a diagram illustrating an effect of an output current of a rectification control circuit for outputting a large current by an LLC according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and the 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.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be connected or detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above should not be understood to necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.

Referring to fig. 1-2, the present invention provides a rectification control circuit for outputting a large current from an LLC, including a first primary switch module 10, a second primary switch module 20, a transformer T1, a first secondary MOS transistor Q3, a second secondary MOS transistor Q4, a first inductor L1, a second inductor L2, and an output capacitor C4. According to the scheme, the first primary side switch module 10 and the second primary side switch module 20 are alternately conducted, and the first secondary side MOS tube Q3 and the second secondary side MOS tube Q4 which are located on the secondary side are alternately and complementarily conducted, so that the current flowing through the output capacitor C4 is always 2 paths of current, the problem of ripple current of the output capacitor C4 is solved, and the soft switching characteristic of LLC is kept.

In this embodiment, the first inductor L1 and the second inductor L2 are energy storage inductors, and the energy storage inductors use mutual conversion between electromagnetic energy to temporarily store electric energy.

In this embodiment, the output capacitor C4 is an electrolytic capacitor, and the capacitance per unit volume of the electrolytic capacitor is very large to effectively perform energy storage discharge.

Referring to fig. 1, an input terminal of the first primary side switch module 10 is connected to a power input, an output terminal of the first primary side switch module 10 is connected to an input terminal of the second primary side switch module 20 and a first terminal of a primary winding Np of a transformer T1, an output terminal of the second primary side switch module 20 and a second terminal of the primary winding Np of the transformer T1 are grounded, wherein the first primary side switch module 10, the second primary side switch module 20 and the primary winding Np of the transformer T1 form an LCC resonant half bridge.

As shown in fig. 1, a first end of a secondary winding Ns of a transformer T1 is connected to a first end of a first inductor L1 and a G pole of a second secondary MOS tube Q4, a second end of the secondary winding Ns of the transformer T1 is connected to a first end of a second inductor L2 and a G pole of a first secondary MOS tube Q3, a D pole of the first secondary MOS tube Q3 is connected to a first end of a first inductor L1, a D pole of the second secondary MOS tube Q4 is connected to a first end of a second inductor L2, S poles of the first secondary MOS tube Q3 and the second secondary MOS tube Q4 are connected to a negative pole of an output capacitor C4, and second ends of the first inductor L1 and the second inductor L2 are connected to a positive output terminal of an output capacitor C4, wherein the secondary winding Ns of the transformer T1, the first secondary MOS tube Q3, the second secondary MOS tube Q4, the first inductor L585, the second inductor L2 and the output capacitor 57324 form a current-doubling rectifying circuit.

Referring to fig. 1, the rectification control circuit for LLC outputting large current further includes a filter capacitor C8, a first end of the filter capacitor C8 is connected to a second end of the primary winding Np of the transformer T1, a second end of the filter capacitor C8 is grounded, and the filter capacitor C8 cooperates with the primary winding Np of the transformer T1 of the first primary side switch module 10 and the second primary side switch module 20 to form an LCC resonant half bridge.

Referring to fig. 1, the first primary side switching module 10 includes a first primary side MOS transistor Q1, a first transistor Q5, a first resistor R1, a second resistor R2, and a third resistor R3; the power input is connected with the D pole of a first primary side MOS tube Q1, the G pole of the first primary side MOS tube Q1 is connected with the first ends of a first resistor R1 and a second resistor R2, the second end of the first resistor R1 is connected with the e pole of a first triode Q5 and the first end of a third resistor R3, the b pole of the first triode Q5 is connected with the second end and a first control terminal pin of the third resistor R3, and the c pole of a first triode Q5 and the second end of a second resistor R2 are connected with the first end of a primary winding Np of a transformer T1.

Referring to fig. 1, the second primary side switching module 20 includes a second primary side MOS transistor Q2, a second transistor Q6, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6; the D pole of the second primary side MOS transistor Q2 is connected to the first end of the primary winding Np of the transformer T1, the G pole of the second primary side MOS transistor Q2 is connected to the first ends of the fourth resistor R4 and the fifth resistor R5, the second end of the fourth resistor R4 is connected to the e pole of the second triode Q6 and the first end of the sixth resistor R6, the b pole of the second triode Q6 is connected to the second end and the second control terminal pin of the sixth resistor R6, and the c pole of the second triode Q6, the second end of the fifth resistor R5 and the S pole of the second primary side MOS transistor Q2 are grounded.

Referring to fig. 1, the rectification control circuit for LLC outputting large current further includes a first secondary capacitor C1, a seventh resistor R7, and an eighth resistor R8, a first end of the first secondary capacitor C1 is connected to the second end of the secondary winding Ns of the transformer T1, a second end of the first secondary capacitor C1 is connected to the first end of the seventh resistor R7, second ends of the seventh resistor R7 and the eighth resistor R8 are connected to the G-pole of the first secondary MOS transistor Q3, and a first end of the eighth resistor R8 is connected to the S-pole of the first secondary MOS transistor Q3.

Referring to fig. 1, the rectification control circuit for LLC outputting large current further includes a second secondary capacitor C2, a ninth resistor R9 and a tenth resistor R10, a first end of the second secondary capacitor C2 is connected to the first end of the secondary winding Ns of the transformer T1, a second end of the second secondary capacitor C2 is connected to the first end of the ninth resistor R9, second ends of the ninth resistor R9 and the tenth resistor R10 are connected to the G-pole of the second secondary MOS transistor Q4, and a first end of the tenth resistor R10 is connected to the S-pole of the second secondary MOS transistor Q4.

Referring to fig. 1, the rectification control circuit for LLC outputting large current further includes an input capacitor C6, the positive electrode of the input capacitor C6 is connected to the input end of the first primary side switch module 10, i.e. the power input, and the negative electrode is grounded.

In this embodiment, a first primary side MOS tube Q1, a second primary side MOS tube Q2, a transformer T1, and a filter capacitor C8 on the primary side of the rectification control circuit that outputs a large current from an LLC form an LLC resonant half bridge; the energy storage inductors L1 and L2, the first secondary MOS transistor Q3 and the second secondary MOS transistor Q4 (self-driven rectifier) form a current doubler rectifier circuit. During operation, the MOS transistors Q1 and Q2 with the primary side serving as a switch are complementarily and alternately conducted at a duty ratio of 0.5, and the MOS transistors Q3 and Q4 with the secondary side serving as a rectifier are also complementarily and alternately conducted at a duty ratio of 0.5, so that the rectification control circuit of the present embodiment, which outputs a large current, is in steady-state operation. The specific working process is as follows:

a) when the Q1 of the primary LLC resonant half bridge is switched on, the Q4 of the secondary current-doubling rectifying circuit is switched on simultaneously, and a current path of a current divider 2 flows into the output capacitor C4.

Current path 1: the secondary winding Ns is charged and stored with energy through the first inductor L1, the current of the L1 is increased, and the current of the output inductor IL1 is larger than the current of the output capacitor C4 and the synchronous rectifier Q4.

Current path 2: the second inductor L2 discharges, the L2 current attenuates, and the output inductor current IL2 is larger than the output capacitor C4 is larger than the synchronous rectifier Q4.

2) When the Q2 of the primary LLC resonant half bridge is conducted and the Q3 of the secondary current-doubling rectifying circuit is conducted simultaneously, the current also flows into the output capacitor C4 by 2 current paths.

Current path 1: the secondary winding Ns is charged and stored with energy through the second inductor L2, the current is increased, and the inductor current IL2, the capacitor C4 and the synchronous rectifier Q3 are output.

Current path 2: the first inductor L1 discharges, the L1 current attenuates, and the output inductor current IL1 is larger than the output capacitor C4 is larger than the synchronous rectifier Q3.

Thus, the switching tubes Q1& Q2 of the primary LLC resonant half bridge are alternately turned on, and the secondary rectifiers Q3 and Q4 are also alternately turned on, and the currents flowing through the output capacitors are always 2 currents (IL1 and IL2), so called double current rectification. As shown in fig. 2, 2 paths of inductor currents (IL1 and IL2) flow into the output capacitor C4, and the output current Iout of the output capacitor C4 is IL1+ IL2, so that the ripple current of the output capacitor is greatly reduced, the requirements on the capacity and the volume of the output capacitor are further reduced, the production cost is reduced, and the service life of the switching power supply is prolonged.

It should be understood that the rectification control circuit for outputting large current by LLC in the present invention can be applied to power supply products requiring large current output, such as switching power supplies, adapters, LED display screen power supplies, LED centralized power supply driving power supplies, etc., to reduce the capacity and volume of the output capacitor C4 applied to the power supply products, correspondingly reduce the production cost, and prolong the service life of the power supply products.

According to the rectification control circuit for the LLC to output the large current, the rectification control circuit comprises the first primary side switch module 10 and the second primary side switch module 20 which are alternately conducted, and the first secondary side MOS tube Q3 and the second secondary side MOS tube Q4 on the secondary side of the transformer T1 are alternately conducted in a complementary mode, so that the current flowing through the output capacitor C4 is always 2 paths of current, the problem of ripple current flowing through the output capacitor C4 is solved, and meanwhile the soft switching characteristic of the LLC is kept.

The invention further provides a switching power supply, which comprises the rectification control circuit for outputting the large current by the LLC in the embodiment so as to improve the problem of ripple current of the output current of the switching power supply and simultaneously keep the soft switching characteristic of the LLC.

It should be understood that the switching power supply described in this embodiment can be applied to power supply products that need to output a large current, such as LED display screen products or LED centralized power supply products.

The switching power supply comprises a rectification control circuit of LLC output large current, a first primary side switch module and a second primary side switch module are alternately conducted, and a first secondary side MOS tube and a second secondary side MOS tube on a secondary side of a transformer are alternately and complementarily conducted, so that current flowing through an output capacitor is 2 paths of current all the time, the problem of ripple current of the output capacitor is solved, and meanwhile, the soft switching characteristic of LLC is ensured.

The technical contents of the present invention are further illustrated by the examples only for the convenience of the reader, but the embodiments of the present invention are not limited thereto, and any technical extension or re-creation based on the present invention is protected by the present invention. The protection scope of the invention is subject to the claims.