CN212875658U - Control circuit applied to LLC resonant converter - Google Patents
Control circuit applied to LLC resonant converter Download PDFInfo
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- CN212875658U CN212875658U CN202021468069.4U CN202021468069U CN212875658U CN 212875658 U CN212875658 U CN 212875658U CN 202021468069 U CN202021468069 U CN 202021468069U CN 212875658 U CN212875658 U CN 212875658U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The utility model discloses a be applied to LLC resonant converter's control circuit, include: the microprocessor is used for collecting the output voltage of the switching power supply; the optical coupling module is connected with the microprocessor; the microprocessor controls the electronic switch to be turned on and off through the optical coupling module, and then the PFC voltage is adjusted. The utility model discloses an adjustment PFC voltage realizes that LLC resonant converter also enables switching frequency near resonant frequency when output voltage reduces, guarantees the high efficiency low-power consumption of power to and LLC resonant converter output voltage's wide range, but wide application in switching power supply technical field.
Description
Technical Field
The utility model relates to a switching power supply technical field especially relates to a be applied to LLC resonant converter's control circuit.
Background
The LLC circuit topology is superior to conventional topologies, zero-voltage switching can be achieved within a wide load range, high efficiency is achieved, and the circuit can obtain the highest conversion efficiency when the switching frequency is equal to the resonant frequency. In a wide output voltage range, when the switching frequency is higher than the resonance frequency and deviates from the resonance point, the switching loss and the transformer loss of the main power mosfet tube are increased to generate heat, and even the switching mosfet tube and the transformer are thermally damaged when the heat generation is serious. The switching frequency is the switching frequency of an MOS (metal oxide semiconductor) tube of a primary side main power circuit of the switching power supply, and the resonant frequency is the frequency of an LLC (logical link control) resonant half-bridge resonant circuit.
SUMMERY OF THE UTILITY MODEL
In order to solve the above technical problem, the present invention provides a control circuit for an LLC resonant converter.
The utility model adopts the technical proposal that:
a control circuit for application to an LLC resonant converter, comprising:
the microprocessor is used for collecting the output voltage of the switching power supply;
the optical coupling module is connected with the microprocessor;
the microprocessor controls the electronic switch to be turned on and off through the optical coupling module, and then the PFC voltage is adjusted.
Further, the PFC voltage adjustment module further includes a first resistance unit, a second resistance unit, and a third resistance unit;
one end of the first resistance unit, one end of the second resistance unit and one end of the third resistance unit are connected with the voltage fixing end, the other end of the first resistance unit is used as an output end of PFC voltage, the other end of the second resistance unit is grounded, and the other end of the third resistance unit is grounded through the electronic switch.
Further, the first resistance unit comprises a first resistance, a second resistance, a third resistance and a fourth resistance which are connected in series in sequence.
Further, the second resistance unit includes a fifth resistance and a sixth resistance connected in parallel to each other.
Further, the second resistance unit further comprises a first capacitor, and the first capacitor is connected in parallel with the fifth resistor.
Further, the control circuit further comprises a voltage acquisition module, wherein the voltage acquisition module comprises a fourteenth resistor and a fifteenth resistor;
one end of the fourteenth resistor is used for collecting output voltage of the switching power supply, the other end of the fourteenth resistor is grounded through a fifteenth resistor, and a connection point between the fourteenth resistor and the fifteenth resistor is connected with the microprocessor.
Further, the electronic switch is an NPN type bipolar transistor.
The utility model has the advantages that: the utility model discloses an adjustment PFC voltage realizes that LLC resonant converter also enables switching frequency near resonant frequency when output voltage reduces, guarantees the high efficiency low-power consumption of power to and LLC resonant converter output voltage's wide range.
Drawings
Fig. 1 is an electronic circuit diagram of a control circuit applied to an LLC resonant converter according to an embodiment of the present invention.
Detailed Description
This section will describe in detail the embodiments of the present invention, preferred embodiments of the present invention are shown in the attached drawings, which are used to supplement the description of the text part of the specification with figures, so that one can intuitively and vividly understand each technical feature and the whole technical solution of the present invention, but they cannot be understood as the limitation of the protection scope of the present invention.
In the description of the present invention, it should be understood that the orientation or positional relationship indicated with respect to the orientation description, such as up, down, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, a plurality of means are one or more, a plurality of means are two or more, and the terms greater than, less than, exceeding, etc. are understood as not including the number, and the terms greater than, less than, within, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless there is an explicit limitation, the words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in combination with the specific contents of the technical solution.
A control circuit for application to an LLC resonant converter, comprising:
the microprocessor is used for collecting the output voltage of the switching power supply;
the optical coupling module is connected with the microprocessor;
the PFC voltage adjusting module comprises an electronic switch, and the microprocessor controls the electronic switch to be turned on or turned off through the optocoupler module so as to adjust the PFC voltage.
In this embodiment, this microprocessor is power secondary singlechip for detect switching power supply's output voltage, and according to output voltage control opto-coupler module's operating condition, for example when detecting that output voltage is in first voltage range, output high voltage control opto-coupler module switches on, when detecting that output voltage is in second voltage range, control opto-coupler module does not switch on. The optical coupling module mainly comprises an optical coupling device and related peripheral components. When the optical coupling module is conducted, the electronic switch is controlled to be turned off so that the PFC voltage output by the PFC voltage adjusting module is a first voltage value, and when the optical coupling module is not conducted, the electronic switch is controlled to be conducted so that the PFC voltage output by the PFC voltage adjusting module is a second voltage value. In the LLC resonance half-bridge circuit, when the switching frequency is equal to the resonant frequency, the highest power supply efficiency is realized, when the output voltage is reduced, the switching frequency can be changed and increased and deviates from the resonant frequency, and when the PFC voltage is reduced, the switching frequency is reduced, so that the switching frequency is equal to the resonant frequency, the LLC resonance converter can also enable the switching frequency to be close to the resonant frequency when the output voltage is reduced, and the high efficiency and the low power consumption of the power supply are ensured. The PFC voltage is a boosted voltage of the PFC circuit (i.e., an input voltage of the LLC circuit).
In some embodiments, the PFC voltage adjustment module further includes a first resistance unit, a second resistance unit, and a third resistance unit;
one end of the first resistance unit, one end of the second resistance unit and one end of the third resistance unit are connected with the voltage fixing end, the other end of the first resistance unit is used as an output end of PFC voltage, the other end of the second resistance unit is grounded, and the other end of the third resistance unit is grounded through the electronic switch.
In this embodiment, the voltage fixing end is a pin voltage end of the chip VSENSE, and the pin voltage of the chip VSENSE is fixed, specifically 5V.
In some embodiments, the first resistance unit includes a first resistance, a second resistance, a third resistance, and a fourth resistance connected in series in this order.
In some embodiments, the second resistance unit includes a fifth resistance and a sixth resistance connected in parallel with each other.
In some embodiments, the second resistance unit further comprises a first capacitor connected in parallel with the fifth resistance. And filtering is carried out through the first capacitor, so that noise waves in the circuit are reduced.
In some embodiments, the circuit for realizing the wide range of the output voltage of the LLC resonant converter further comprises a voltage acquisition module, the voltage acquisition module comprising a fourteenth resistor and a fifteenth resistor;
one end of the fourteenth resistor is used for collecting the output voltage of the switching power supply, the other end of the fourteenth resistor is grounded through the fifteenth resistor, and a connecting point between the fourteenth resistor and the fifteenth resistor is connected with the microprocessor.
In some embodiments, the electronic switch is an NPN type bipolar transistor. The electronic switch can be realized by devices such as a triode, a field effect transistor and the like, and is realized by an NPN type bipolar transistor in the embodiment.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
As shown in fig. 1, the present embodiment provides a control circuit applied to an LLC resonant converter, including a voltage acquisition module, a microprocessor U1, an optical coupling module, and a PFC voltage adjustment module;
the voltage acquisition module comprises a fourteenth resistor R14 and a fifteenth resistor R15; one end of the fourteenth resistor R14 is used for collecting the output voltage of the switching power supply, the other end of the fourteenth resistor R14 is grounded through a fifteenth resistor, and a connection point between the fourteenth resistor R14 and the fifteenth resistor R15 is connected with the microprocessor;
the optical coupler module comprises an optical coupler, an eighth resistor R8 and a ninth resistor R9;
the PFC voltage adjusting module comprises a first resistor unit 1, a second resistor unit 2 and a third resistor unit, wherein the first resistor unit 1 comprises a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4 which are sequentially connected in series, the second resistor unit 2 comprises a fifth resistor R5 and a sixth resistor R6 which are mutually connected in parallel, and the third resistor unit comprises a seventh resistor R7.
The working principle of the circuit is as follows: output voltage is detected through a pin 28 of a power supply secondary singlechip (namely a microprocessor) U1, when the detected voltage is 40-50V, a pin 8 of the singlechip U1 is at a high level, an optocoupler OT1 is conducted, a Q1 is not conducted, PFC voltage is 391.6V, when the detected voltage is 50-60V, a pin 8 of the singlechip U1 is at a low level, an optocoupler OT1 is not conducted, a Q1 is conducted, and PFC voltage is 411V. The PFC voltage is adjusted by detecting the output voltage, so that the switching frequency of the LLC resonant converter can be kept near the resonant frequency when the output voltage is reduced, and the high efficiency and low power consumption of a power supply are ensured.
In this embodiment, the circuit parameters are specifically as follows:
rated output voltage: 40 Vdc-60 Vdc
First resistance R1: 200K, second resistance R2: 200K, third resistor R3: 200K, fourth resistor R4: 200K, fifth resistor R5: 12K, sixth resistor R6: 75K, seventh resistor R7: 200K
When the output voltage is 40-50V, the PFC voltage:
when the output voltage is 50-60V, the PFC voltage:
as is apparent from the above description, the present circuit is added to adjust the feedback of the PFC by detecting the output voltage, thereby changing the PFC voltage.
While the preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and such equivalent modifications or substitutions are intended to be included within the scope of the present invention as defined by the appended claims.
Claims (7)
1. A control circuit for use in an LLC resonant converter, comprising:
the microprocessor is used for collecting the output voltage of the switching power supply;
the optical coupling module is connected with the microprocessor;
the microprocessor controls the electronic switch to be turned on and off through the optical coupling module, and then the PFC voltage is adjusted.
2. The control circuit applied to the LLC resonant converter according to claim 1, wherein said PFC voltage adjustment module further comprises a first resistance unit, a second resistance unit and a third resistance unit;
one end of the first resistance unit, one end of the second resistance unit and one end of the third resistance unit are connected with the voltage fixing end, the other end of the first resistance unit is used as an output end of PFC voltage, the other end of the second resistance unit is grounded, and the other end of the third resistance unit is grounded through the electronic switch.
3. The control circuit applied to the LLC resonant converter according to claim 2, wherein said first resistance unit comprises a first resistor, a second resistor, a third resistor and a fourth resistor connected in series in sequence.
4. The control circuit applied to the LLC resonant converter as claimed in claim 2, wherein said second resistance unit comprises a fifth resistance and a sixth resistance connected in parallel with each other.
5. The control circuit applied to the LLC resonant converter as claimed in claim 4, wherein said second resistance unit further comprises a first capacitor, said first capacitor being connected in parallel with said fifth resistor.
6. The control circuit applied to the LLC resonant converter according to claim 1, wherein said control circuit further comprises a voltage acquisition module, said voltage acquisition module comprising a fourteenth resistor and a fifteenth resistor;
one end of the fourteenth resistor is used for collecting output voltage of the switching power supply, the other end of the fourteenth resistor is grounded through a fifteenth resistor, and a connection point between the fourteenth resistor and the fifteenth resistor is connected with the microprocessor.
7. A control circuit for an LLC resonant converter according to any one of claims 1-6, wherein said electronic switch is an NPN bipolar transistor.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202021468069.4U CN212875658U (en) | 2020-07-22 | 2020-07-22 | Control circuit applied to LLC resonant converter |
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| CN202021468069.4U CN212875658U (en) | 2020-07-22 | 2020-07-22 | Control circuit applied to LLC resonant converter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115021582A (en) * | 2022-08-04 | 2022-09-06 | 深圳市高斯宝电气技术有限公司 | Closed-loop control method of LLC switching power supply |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115021582A (en) * | 2022-08-04 | 2022-09-06 | 深圳市高斯宝电气技术有限公司 | Closed-loop control method of LLC switching power supply |
| CN115021582B (en) * | 2022-08-04 | 2023-01-10 | 深圳市高斯宝电气技术有限公司 | Closed-loop control method of LLC switching power supply |
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