CN111146952A - Flyback converter - Google Patents

Flyback converter Download PDF

Info

Publication number
CN111146952A
CN111146952A CN202010073770.4A CN202010073770A CN111146952A CN 111146952 A CN111146952 A CN 111146952A CN 202010073770 A CN202010073770 A CN 202010073770A CN 111146952 A CN111146952 A CN 111146952A
Authority
CN
China
Prior art keywords
unit
voltage
resistor
voltage division
auxiliary winding
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202010073770.4A
Other languages
Chinese (zh)
Other versions
CN111146952B (en
Inventor
严亮
李鹏
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Msj Systems LLC
Original Assignee
Msj Systems LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Msj Systems LLC filed Critical Msj Systems LLC
Priority to CN202010073770.4A priority Critical patent/CN111146952B/en
Publication of CN111146952A publication Critical patent/CN111146952A/en
Application granted granted Critical
Publication of CN111146952B publication Critical patent/CN111146952B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0016—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters
    • 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

Abstract

The invention relates to a flyback converter, comprising: the device comprises a transformer, a power switch circuit, a voltage input circuit, a voltage output circuit, an auxiliary winding, a controller and a first sampling circuit, wherein the transformer comprises a primary winding and a secondary winding; the second sampling circuit is connected with the second end of the auxiliary winding and used for acquiring a second sampling signal corresponding to the second end of the auxiliary winding; the controller is respectively connected with the first sampling circuit and the second sampling circuit and used for receiving the first sampling signal and the second sampling signal to obtain the output voltage of the voltage output circuit when the power switch circuit is switched off. The invention has wide application range and can be applied to various scenes.

Description

Flyback converter
Technical Field
The invention relates to the technical field of power supplies, in particular to a flyback converter.
Background
The loop control of a conventional flyback converter directly detects an output voltage, generates a feedback and compensation signal, and determines a duty ratio of a main power switch according to the compensation signal, thereby controlling an output quantity, such as the output voltage. When electrical isolation is required between the input and output of a switching power supply, such as in an off-line converter, the feedback compensation circuit and the control circuit are often on both sides of the electrical isolation device, i.e., on one side, the input side (referred to herein as the "primary side") and on the other side, the output side (referred to herein as the "secondary side"). There is no direct common electrical connection between the primary and secondary sides, and isolation devices such as optocouplers are typically used to transmit signals. The isolation device and its accompanying circuitry add cost and size to the system and the primary side detection method is often used in many low cost applications. According to the method, according to the transformer coupling principle, when a primary side main switch is turned off and an output rectifier tube is turned on, a secondary side winding of a transformer bears output voltage, and the voltage on the secondary winding is proportional to the voltage of the output winding through the coupling of the secondary winding and the output winding. Thus, the control circuit on the primary side can indirectly detect the value of the output voltage by detecting the voltage across the auxiliary winding.
In addition to providing output voltage detection, the auxiliary winding often also provides power for the primary control circuit. Fig. 1 is a schematic diagram of a conventional primary side feedback circuit, in which an input voltage Vin, S1 is a primary side main switching tube. The transformer Tx1 has a primary winding Np, a secondary winding Ns, and an auxiliary winding Na. The control circuit output signal DRV drives S1 on and off. When S1 is turned on, the transformer accepts and stores energy from the input Vin. When S1 turns off, the transformer releases energy to the output. One end of the auxiliary winding is grounded, and the other end of the auxiliary winding supplies power to the control circuit through the rectifier tube. The control circuit power is supplied by the auxiliary winding through a rectifier D2. The positive end of D2 is connected to the flyback positive end of the auxiliary winding, and the negative end of D2 is connected to the control circuit. After the auxiliary winding voltage is divided by the resistors R1 and R2, a sampling signal is taken from the connection point of R1 and R2. The feedback signal in the feedback sampling method is common to the control circuit of the primary side circuit, so that a detection signal can be obtained by using one control line actually.
However, the technical scheme is only suitable for the rectifier tube for supplying power to the auxiliary circuit to be connected with the positive end of the auxiliary winding during flyback. If in application, the rectifier tube of the auxiliary circuit is connected to the negative terminal of the auxiliary winding during flyback, the sampling signal cannot be obtained by the method described above. In practical applications, when the rectifier is required to be placed at the negative terminal of the flyback winding for various reasons, such as for convenience of layout, or for changing electromagnetic interference characteristics, etc., the conventional single detection path cannot obtain a correct detection result of the output voltage.
Disclosure of Invention
The present invention is directed to a flyback converter, which overcomes some of the above-mentioned drawbacks of the prior art.
The technical scheme adopted by the invention for solving the technical problems is as follows: constructing a flyback converter comprising: a transformer including a primary winding and a secondary winding, a power switch circuit and a voltage input circuit connected to the primary winding, a voltage output circuit connected to the secondary winding, an auxiliary winding coupled to the secondary winding, a controller connected to the power switch circuit, and
the first sampling circuit is connected with the first end of the auxiliary winding and used for acquiring a first sampling signal corresponding to the first end of the auxiliary winding; and
the second sampling circuit is connected with the second end of the auxiliary winding and used for acquiring a second sampling signal corresponding to the second end of the auxiliary winding;
the controller is respectively connected with the first sampling circuit and the second sampling circuit and used for receiving the first sampling signal and the second sampling signal to obtain the output voltage of the voltage output circuit when the power switch circuit is switched off.
Preferably, the flyback converter of the present invention further includes a first rectifying unit connected to the auxiliary winding;
the first end of the first rectifying unit is connected with the second end of the auxiliary winding, and the second end of the first rectifying unit is grounded.
Preferably, in a flyback converter of the present invention, the first rectifying unit includes a rectifying tube D2, the positive electrode of the rectifying tube D2 is grounded, and the negative electrode of the rectifying tube D2 is connected to the second end of the auxiliary winding.
Preferably, in a flyback converter of the present invention, the first sampling unit includes a first voltage dividing unit and a second voltage dividing unit;
the first end of the first voltage division unit is connected with the first end of the auxiliary winding, the second end of the first voltage division unit is respectively connected with the controller and the first end of the second voltage division unit, and the second end of the second voltage division unit is connected with the second end of the auxiliary winding; or
The second sampling unit comprises a third partial pressure unit and a fourth partial pressure unit;
the first end of the third voltage division unit is connected with the first end of the auxiliary winding, the second end of the third voltage division unit is respectively connected with the controller and the first end of the fourth voltage division unit, and the second end of the fourth voltage division unit is connected with the second end of the auxiliary winding.
Preferably, in a flyback converter of the present invention, the first voltage dividing unit includes a voltage dividing resistor R1, a first end of the voltage dividing resistor R1 is connected to a first end of the auxiliary winding, and a second end of the voltage dividing resistor R1 is connected to the controller;
the second voltage division unit comprises a voltage division resistor R2, a first end of the voltage division resistor R2 is connected with a second end of the voltage division resistor R1, and a second end of the voltage division resistor R2 is connected with a second end of the auxiliary winding; or
The third voltage division unit comprises a voltage division resistor R11, a first end of the voltage division resistor R11 is connected with a first end of the auxiliary winding, and a second end of the voltage division resistor R11 is connected with the controller;
the fourth voltage division unit comprises a voltage division resistor R21, a first end of the voltage division resistor R21 is connected with a second end of the voltage division resistor R11, and a second end of the voltage division resistor R21 is connected with a second end of the auxiliary winding.
Preferably, the flyback converter of the present invention further includes a first current limiting unit and/or a second current limiting unit;
the first end of the first current limiting unit is connected with the controller, and the second end of the first current limiting unit is connected with the first sampling unit;
and the first end of the second current limiting unit is connected with the controller, and the second end of the second current limiting unit is connected with the second sampling unit.
Preferably, in a flyback converter of the present invention, the first current limiting unit includes a current limiting resistor R5, a first end of the current limiting resistor R5 is connected to the controller, and a second end of the current limiting resistor R5 is connected to the first sampling unit; and/or
The second current limiting unit comprises a current limiting resistor R6, a first end of the current limiting resistor R6 is connected with the controller, and a second end of the current limiting resistor R6 is connected with the second sampling unit.
Preferably, in the flyback converter of the present invention, the power switch circuit includes a MOS transistor S1, a gate of the MOS transistor S1 is connected to the controller, a source of the MOS transistor S1 is connected to the second end of the primary winding, and a drain of the MOS transistor S1 is grounded.
Preferably, in a flyback converter of the present invention, the voltage input circuit includes a second rectifying unit, a first end of the second rectifying unit is connected to a first end of the primary winding, and a second end of the second rectifying unit is connected to a second end of the primary winding; and/or
The voltage output circuit comprises a third rectifying unit, wherein the first end of the third rectifying unit is connected with the first end of the secondary winding, and the second end of the third rectifying unit is used for outputting the output voltage.
The third rectifying unit comprises a rectifying tube D1, the positive electrode of the rectifying tube D1 is connected with the first end of the secondary winding, and the negative electrode of the rectifying tube D1 is used for outputting the output voltage.
The flyback converter has the following beneficial effects: the method has wide application range and can be suitable for various scenes.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
fig. 1 is a circuit schematic diagram of a prior art flyback converter;
fig. 2 is a schematic structural diagram of a flyback converter of the present invention;
FIG. 3 is a schematic circuit diagram of an embodiment of a flyback converter of the present invention;
fig. 4 is a circuit schematic of another embodiment of a flyback converter of the present invention;
fig. 5 is a circuit schematic diagram of another embodiment of a flyback converter of the present invention.
Detailed Description
For a more clear understanding of the technical features, objects and effects of the present invention, embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
As shown in fig. 2, in a first embodiment of a flyback converter of the present invention, the flyback converter includes: the power supply comprises a transformer comprising a primary winding 210 and a secondary winding 220, a power switch circuit 40 and a voltage input circuit 10 which are connected with the primary winding 210, a voltage output circuit 30 which is connected with the secondary winding 220, an auxiliary winding 70 which is coupled with the secondary winding 220, a controller 50 which is connected with the power switch circuit 40, and a first sampling circuit 61 which is connected with a first end of the auxiliary winding 70 and is used for acquiring a first sampling signal corresponding to the first end of the auxiliary winding 70; and a second sampling circuit 62 connected to a second end of the auxiliary winding 70 for obtaining a second sampling signal corresponding to the second end of the auxiliary winding 70; the controller 50 is respectively connected to the first sampling circuit 61 and the second sampling circuit 62, and is configured to receive the first sampling signal and the second sampling signal to obtain the output voltage of the voltage output circuit 30 when the power switch circuit 40 is turned off. Specifically, the primary winding 210 provides a voltage through the voltage input circuit 10 and controls the voltage output of the voltage output circuit 30 through the power switch circuit 40, and the output of the voltage output circuit 30 supplies power to the controller 50 through the auxiliary winding 70 coupled to the secondary winding 220, so that the controller 50 starts to operate. When the controller 50 starts to operate, that is, when the auxiliary winding 70 couples with the primary winding 210 to generate a voltage, the first sampling circuit 61 obtains a first sampling signal corresponding to a first end of the auxiliary winding 70, the second sampling circuit 62 obtains a second sampling signal corresponding to a second end of the auxiliary winding 70, the voltage of the auxiliary winding 70 can be obtained by comparing the two sampling signals, and further, an output voltage corresponding to the voltage output circuit 30 connected with the secondary winding 220 can be obtained. It can be understood that the voltage parameter corresponding to the first end of the auxiliary winding 70 can be obtained according to the first sampling signal, the voltage parameter corresponding to the second end of the auxiliary winding 70 can be obtained according to the second sampling signal, and the voltage difference between the two ends of the auxiliary winding 70 can be obtained by comparing the two voltage parameters, that is, the output voltage corresponding to the corresponding voltage output circuit 30 is obtained. The circuit has wide application range and can be suitable for various scenes. The control effect of the voltage output is ensured especially when the auxiliary winding 70 and the control circuit are not commonly grounded.
As shown in fig. 3, in an embodiment, the flyback converter of the present invention further includes a first rectifying unit 80 connected to the auxiliary winding 70; a first terminal of the first rectifying unit 80 is connected to the second terminal of the auxiliary winding 70, and a second terminal of the first rectifying unit 80 is grounded. Specifically, the auxiliary winding 70 is rectified by the first rectifying unit 80 to provide the power supply voltage for the controller 50, wherein the first rectifying unit 80 is connected between the second end of the auxiliary winding 70 and the ground, i.e., the second sampling unit may be connected between the first rectifying unit 80 and the auxiliary winding 70.
As shown in fig. 4, in an embodiment, the first sampling unit includes a first voltage dividing unit 612 and a second voltage dividing unit 613; a first end of the first voltage dividing unit 612 is connected to a first end of the auxiliary winding 70, a second end of the first voltage dividing unit 612 is connected to first ends of the controller 50 and the second voltage dividing unit 613, respectively, and a second end of the second voltage dividing unit 613 is connected to a second end of the auxiliary winding 70. Specifically, the first sampling signal corresponding to the first end of the auxiliary winding 70 may be implemented by a voltage dividing circuit. That is, the first voltage dividing unit 612 and the second voltage dividing unit 613 form a voltage dividing circuit, the second end of the second voltage dividing unit 613 in the voltage dividing circuit is sampled to obtain a first sampling signal, and according to the first sampling signal and the voltage dividing circuit, the voltage parameter of the first end of the auxiliary winding 70 can be obtained through corresponding calculation.
Further, the first voltage dividing unit 612 includes a voltage dividing resistor R1, a first end of the voltage dividing resistor R1 is connected to a first end of the auxiliary winding 70, and a second end of the voltage dividing resistor R1 is connected to the controller 50; the second voltage dividing unit 613 includes a voltage dividing resistor R2, a first terminal of the voltage dividing resistor R2 is connected to the second terminal of the voltage dividing resistor R1, and a second terminal of the voltage dividing resistor R2 is connected to the second terminal of the auxiliary winding 70. Specifically, a voltage dividing circuit is formed by the voltage dividing resistor R1 and the voltage dividing resistor R2, and the first sampling unit can acquire the voltage parameter of the first end of the auxiliary winding 70 according to the acquired voltage dividing parameter of the voltage dividing resistor R2, that is, the acquired first sampling signal corresponds to the acquired first sampling signal, and the relationship between the voltage dividing resistor R1 and the voltage dividing resistor R2.
As shown in fig. 4, in an embodiment, the second sampling unit includes a third partial pressure unit 622 and a fourth partial pressure unit 623; a first end of the third voltage dividing unit 622 is connected to a first end of the auxiliary winding 70, a second end of the third voltage dividing unit 622 is connected to first ends of the controller 50 and the fourth voltage dividing unit 623, respectively, and a second end of the fourth voltage dividing unit 623 is connected to a second end of the auxiliary winding 70. Specifically, the second sampling signal corresponding to the second end of the auxiliary winding 70 may be implemented by a voltage dividing circuit. That is, the third voltage dividing unit 622 and the fourth voltage dividing unit 623 constitute a voltage dividing circuit, the second end of the fourth voltage dividing unit 623 in the voltage dividing circuit is sampled to obtain a second sampling signal, and according to the second sampling signal and the voltage dividing circuit, the voltage parameter of the second end of the auxiliary winding 70 can be correspondingly calculated and obtained.
Further, the third voltage dividing unit 622 includes a voltage dividing resistor R11, a first end of the voltage dividing resistor R11 is connected to the first end of the auxiliary winding 70, and a second end of the voltage dividing resistor R11 is connected to the controller 50; the fourth voltage dividing unit 623 comprises a voltage dividing resistor R21, wherein a first end of the voltage dividing resistor R21 is connected to a second end of the voltage dividing resistor R11, and a second end of the voltage dividing resistor R21 is connected to a second end of the auxiliary winding 70. Specifically, a voltage dividing circuit is formed by the voltage dividing resistor R11 and the voltage dividing resistor R21, and the second sampling unit can acquire the voltage parameter of the second end of the auxiliary winding 70 according to the acquired voltage dividing parameter of the voltage dividing resistor R21, that is, the acquired voltage dividing parameter corresponds to the second sampling signal, and the relationship between the voltage dividing resistor R11 and the voltage dividing resistor R21.
In an embodiment, the flyback converter of the present invention further includes a first current limiting unit 611 and/or a second current limiting unit 621; a first end of the first current limiting unit 611 is connected to the controller 50, and a second end of the first current limiting unit 611 is connected to the first sampling unit; a first end of the second current limiting unit 621 is connected to the controller 50, and a second end of the second current limiting unit 621 is connected to the second sampling unit. Specifically, since the sampling voltages Va and Vb may have sampling voltages higher than Vcc or lower than GND, in order to avoid a large current caused by an excessive voltage difference, the first sampling signal obtained by the first sampling unit may be current-limited by the first current-limiting unit 611 and then input to the controller 50 for processing. The second sampling signal obtained by the second sampling unit may be current-limited by the second current-limiting power supply and then input to the controller 50 for processing.
In an example, the first current limiting unit 611 includes a current limiting resistor R5, a first end of the current limiting resistor R5 is connected to the controller 50, and a second end of the current limiting resistor R5 is connected to the first sampling unit; in another embodiment, the second current limiting unit 621 includes a current limiting resistor R6, a first end of the current limiting resistor R6 is connected to the controller 50, and a second end of the current limiting resistor R6 is connected to the second sampling unit. Specifically, on the above basis, both the first current limiting unit 611 and the second current limiting unit 621 may be current limiting resistors, the first current limiting unit 611 is a current limiting resistor R5, the first sampling signal of the first sampling unit, i.e., the sampling voltage Va, is limited by a current limiting resistor R5, and the second current limiting unit 621 is a current limiting resistor R6, and the second sampling signal of the second sampling unit is limited by a current limiting resistor R6.
In one embodiment, the power switch circuit 40 includes a MOS transistor S1, a gate of the MOS transistor S1 is connected to the controller 50, a source of the MOS transistor S1 is connected to the second end of the primary winding 210, and a drain of the MOS transistor S1 is grounded. Specifically, the voltage output of the primary winding 210 is controlled by turning on and off the MOS transistor S1, that is, when the controller 50 outputs a low level, the MOS transistor S1 is turned off, and at this time, the primary winding 210 outputs energy to the secondary winding 220, and the secondary winding 220 outputs a normal voltage. When the controller 50 outputs a high level, the MOS transistor S1 is turned on, the primary winding 210 does not output energy to the secondary winding 220, and the secondary winding 220 does not generate a voltage output.
In one embodiment, the voltage input circuit 10 includes a second rectifying unit 110, a first end of the second rectifying unit 110 is connected to a first end of the primary winding 210, and a second end of the second rectifying unit 110 is connected to a second end of the primary winding 210; in another embodiment, the voltage output circuit 30 includes a third rectifying unit 310, a first end of the third rectifying unit 310 is connected to a first end of the secondary winding 220, and a second end of the third rectifying unit 310 is used for outputting the output voltage. Specifically, the external input voltage connected to the voltage input circuit 10 is rectified by the second rectifying unit 110 to provide the input voltage for the primary winding 210, and the voltage output circuit 30 connected to the secondary winding 220 is rectified by the third rectifying unit 310 to obtain the preset voltage output, wherein the preset voltage output is obtained by rectifying the output of the secondary winding 220.
It is to be understood that the foregoing examples, while indicating the preferred embodiments of the invention, are given by way of illustration and description, and are not to be construed as limiting the scope of the invention; it should be noted that, for those skilled in the art, the above technical features can be freely combined, and several changes and modifications can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention; therefore, all equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims (10)

1. A flyback converter, comprising: a transformer including a primary winding and a secondary winding, a power switch circuit and a voltage input circuit connected to the primary winding, a voltage output circuit connected to the secondary winding, an auxiliary winding coupled to the secondary winding, a controller connected to the power switch circuit, and
the first sampling circuit is connected with the first end of the auxiliary winding and used for acquiring a first sampling signal corresponding to the first end of the auxiliary winding; and
the second sampling circuit is connected with the second end of the auxiliary winding and used for acquiring a second sampling signal corresponding to the second end of the auxiliary winding;
the controller is respectively connected with the first sampling circuit and the second sampling circuit and used for receiving the first sampling signal and the second sampling signal to obtain the output voltage of the voltage output circuit when the power switch circuit is switched off.
2. The flyback converter of claim 1 further comprising a first rectification unit connected to the auxiliary winding;
the first end of the first rectifying unit is connected with the second end of the auxiliary winding, and the second end of the first rectifying unit is grounded.
3. The flyback converter of claim 2 wherein the first rectifying unit includes a rectifier D2, the anode of the rectifier D2 is grounded, and the cathode of the rectifier D2 is connected to the second end of the auxiliary winding.
4. The flyback converter of claim 1 wherein the first sampling unit comprises a first voltage divider unit and a second voltage divider unit;
the first end of the first voltage division unit is connected with the first end of the auxiliary winding, the second end of the first voltage division unit is respectively connected with the controller and the first end of the second voltage division unit, and the second end of the second voltage division unit is connected with the second end of the auxiliary winding; or
The second sampling unit comprises a third partial pressure unit and a fourth partial pressure unit;
the first end of the third voltage division unit is connected with the first end of the auxiliary winding, the second end of the third voltage division unit is respectively connected with the controller and the first end of the fourth voltage division unit, and the second end of the fourth voltage division unit is connected with the second end of the auxiliary winding.
5. The flyback converter of claim 4,
the first voltage division unit comprises a voltage division resistor R1, a first end of the voltage division resistor R1 is connected with a first end of the auxiliary winding, and a second end of the voltage division resistor R1 is connected with the controller;
the second voltage division unit comprises a voltage division resistor R2, a first end of the voltage division resistor R2 is connected with a second end of the voltage division resistor R1, and a second end of the voltage division resistor R2 is connected with a second end of the auxiliary winding; or
The third voltage division unit comprises a voltage division resistor R11, a first end of the voltage division resistor R11 is connected with a first end of the auxiliary winding, and a second end of the voltage division resistor R11 is connected with the controller;
the fourth voltage division unit comprises a voltage division resistor R21, a first end of the voltage division resistor R21 is connected with a second end of the voltage division resistor R11, and a second end of the voltage division resistor R21 is connected with a second end of the auxiliary winding.
6. The flyback converter of claim 4 further comprising a first current limiting unit and/or a second current limiting unit;
the first end of the first current limiting unit is connected with the controller, and the second end of the first current limiting unit is connected with the first sampling unit;
and the first end of the second current limiting unit is connected with the controller, and the second end of the second current limiting unit is connected with the second sampling unit.
7. The flyback converter of claim 6,
the first current limiting unit comprises a current limiting resistor R5, a first end of the current limiting resistor R5 is connected with the controller, and a second end of the current limiting resistor R5 is connected with the first sampling unit; and/or
The second current limiting unit comprises a current limiting resistor R6, a first end of the current limiting resistor R6 is connected with the controller, and a second end of the current limiting resistor R6 is connected with the second sampling unit.
8. The flyback converter of claim 1 wherein the power switching circuit comprises a MOS transistor S1, the gate of the MOS transistor S1 is connected to the controller, the source of the MOS transistor S1 is connected to the second end of the primary winding, and the drain of the MOS transistor S1 is connected to ground.
9. The flyback converter of claim 1,
the voltage input circuit comprises a second rectifying unit, the first end of the second rectifying unit is connected with the first end of the primary winding, and the second end of the second rectifying unit is connected with the second end of the primary winding; and/or
The voltage output circuit comprises a third rectifying unit, wherein the first end of the third rectifying unit is connected with the first end of the secondary winding, and the second end of the third rectifying unit is used for outputting the output voltage.
10. The flyback converter of claim 9,
the second rectifying unit comprises a resistor Rs, a capacitor Cs and a rectifying tube Ds; after the resistor Rs and the capacitor Cs are connected in parallel, one end of the resistor Rs is connected with the first end of the primary winding, the other end of the resistor Rs is connected with the negative electrode of the rectifier tube Ds, and the positive electrode of the rectifier tube Ds is connected with the second end of the primary winding; and/or
The third rectifying unit comprises a rectifying tube D1, the positive electrode of the rectifying tube D1 is connected with the first end of the secondary winding, and the negative electrode of the rectifying tube D1 is used for outputting the output voltage.
CN202010073770.4A 2020-01-22 2020-01-22 Flyback converter Active CN111146952B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010073770.4A CN111146952B (en) 2020-01-22 2020-01-22 Flyback converter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010073770.4A CN111146952B (en) 2020-01-22 2020-01-22 Flyback converter

Publications (2)

Publication Number Publication Date
CN111146952A true CN111146952A (en) 2020-05-12
CN111146952B CN111146952B (en) 2023-06-30

Family

ID=70526887

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010073770.4A Active CN111146952B (en) 2020-01-22 2020-01-22 Flyback converter

Country Status (1)

Country Link
CN (1) CN111146952B (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102013808A (en) * 2010-12-10 2011-04-13 广东美的电器股份有限公司 Output voltage isolation sampling circuit for DC-DC conversion and control method of output voltage isolation sampling circuit
CN110611431A (en) * 2019-09-30 2019-12-24 东南大学 Primary side regulation control system and control method of active clamp flyback converter
CN211670787U (en) * 2020-01-22 2020-10-13 Msj系统有限责任公司 Flyback converter

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102013808A (en) * 2010-12-10 2011-04-13 广东美的电器股份有限公司 Output voltage isolation sampling circuit for DC-DC conversion and control method of output voltage isolation sampling circuit
CN110611431A (en) * 2019-09-30 2019-12-24 东南大学 Primary side regulation control system and control method of active clamp flyback converter
CN211670787U (en) * 2020-01-22 2020-10-13 Msj系统有限责任公司 Flyback converter

Also Published As

Publication number Publication date
CN111146952B (en) 2023-06-30

Similar Documents

Publication Publication Date Title
US7339359B2 (en) Terminal for multiple functions in a power supply
US9209621B2 (en) Power supply system
US8358517B2 (en) Switching power conversion circuit and power supply using same
EP2026453A2 (en) Switching mode power supply apparatus having passive clamp circuit
US20110199796A1 (en) Structure of a power supply
US20150117070A1 (en) Ac-dc converting apparatus and operating method thereof
TW201725839A (en) Power supply apparatus
US9660541B2 (en) Switching power supply device
JP4850212B2 (en) Coil voltage sampling control power converter
CN211670787U (en) Flyback converter
CN111146952B (en) Flyback converter
JP3826804B2 (en) Dual power supply system
CN214315044U (en) Control circuit and power supply conversion system thereof
CN209994279U (en) Switch power supply
JP7051666B2 (en) Switching power supply
EP1099294A1 (en) Switched-mode power supply
CN220570463U (en) Load adjustable circuit, power supply circuit, circuit board and electronic equipment
JP3656911B2 (en) Power circuit
EP3079244B1 (en) Power supply system
JP2000134924A (en) Power circuit
CN111917298B (en) Flyback power supply circuit and control method thereof
KR102624071B1 (en) Determination of input voltage to galvanic isolation point
JP2009213261A (en) Switching power supply apparatus
KR101734572B1 (en) Circuit for detecting ac for power supply
CN116418228A (en) Power supply device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant