CN216390803U - Self-driven synchronous rectification circuit - Google Patents
Self-driven synchronous rectification circuit Download PDFInfo
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- CN216390803U CN216390803U CN202022921433.4U CN202022921433U CN216390803U CN 216390803 U CN216390803 U CN 216390803U CN 202022921433 U CN202022921433 U CN 202022921433U CN 216390803 U CN216390803 U CN 216390803U
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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
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- 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 embodiment of the application discloses self-driven synchronous rectification circuit includes: the circuit comprises a transformer, a first switch circuit, a second switch circuit, a first voltage stabilizing circuit, a first direct current isolating circuit, a second voltage stabilizing circuit, a second direct current isolating circuit and a load circuit. By adopting the embodiment of the application, the adjustment precision and the working reliability of the voltage stabilizing circuit to the driving signal can be improved, and the possibility of damage of the switch tube is effectively reduced.
Description
Technical Field
The application relates to the technical field of drive control, in particular to a self-driven synchronous rectification circuit.
Background
In the field of power supply design, as a common design method, an LLC topology is widely applied to various power supplies. The self-driven synchronous rectification circuit based on the LLC topology mainly comprises a primary coil, a secondary coil and a switching tube, and is mainly characterized in that the switching tube is driven by voltage at one end of the secondary coil, which is at a high potential, and one end of the secondary coil, which is at a low potential, is generally used for outputting the voltage to a load.
In practical applications, the voltage of the secondary winding is mainly affected by the primary winding. However, at the moment of power on/off, the voltage may be unstable, which may cause the voltage at the high-potential end of the secondary winding to be too high, and the precision of the voltage regulator circuit is too low, so that the voltage value of the driving voltage output by the voltage regulator circuit is higher than the upper limit of the gate voltage of the switching tube, and finally the switching tube is damaged. In the prior art, the voltage stabilizing circuit has a small adjustment range for the voltage value of the driving voltage, and cannot meet the application scenario that the voltage value of the driving voltage needs to be adjusted.
SUMMERY OF THE UTILITY MODEL
The embodiment of the application provides a self-driven synchronous rectification circuit, which can improve the adjustment precision and the working reliability of a voltage stabilizing circuit to a driving signal and effectively reduce the possibility of damage to a switching tube. The technical scheme is as follows:
the application provides a self-driven synchronous rectification circuit, includes: the transformer, the first switch circuit, the second switch circuit, the first voltage stabilizing circuit, the first DC isolating circuit, the second voltage stabilizing circuit, the second DC isolating circuit and the load circuit;
the transformer includes: the primary side coil, the first secondary side coil and the second secondary side coil; the synonym end of the first secondary side coil is connected with the synonym end of the second secondary side coil;
the first voltage stabilizing circuit comprises a first three-terminal adjustable shunt reference source, and the second voltage stabilizing circuit comprises a second three-terminal adjustable shunt reference source;
the first switch circuit is connected with the homonymous end of the first secondary side coil, and the second switch circuit is connected with the synonym end of the second secondary side coil;
the first direct current isolating circuit is connected with the synonym end of the second secondary side coil, the first voltage stabilizing circuit is connected with the first direct current isolating circuit, and the first voltage stabilizing circuit is connected with the first switch circuit;
the second direct current isolating circuit is connected with the dotted terminal of the first secondary side coil, the second voltage stabilizing circuit is connected with the second direct current isolating circuit, and the second voltage stabilizing circuit is connected with the second switch circuit;
the load circuit is connected with the synonym end of the first secondary side coil;
the first direct current blocking circuit performs direct current blocking processing on a first signal from the second secondary coil to obtain a first processing signal, transmits the first processing signal to the first voltage stabilizing circuit, performs voltage stabilizing processing on the first processing signal by the first voltage stabilizing circuit to obtain a first driving signal, and transmits the first driving signal to the first switching circuit; the first driving signal is used for enabling the first switching circuit to be in a working state, so that the first switching circuit, the first secondary coil and the load circuit form a loop;
the second direct current blocking circuit performs direct current blocking processing on a second signal from the first secondary coil to obtain a second processing signal, transmits the second processing signal to the second voltage stabilizing circuit, performs voltage stabilizing processing on the second processing signal by the second voltage stabilizing circuit to obtain a second driving signal, and transmits the second driving signal to the second switching circuit; the second driving signal is used for enabling the second switching circuit to be in a working state, so that the second switching circuit, the second secondary coil and the load circuit form a loop.
The beneficial effects brought by the technical scheme provided by some embodiments of the application at least comprise: the three-terminal adjustable shunt reference source is used as a voltage stabilizing tube of the voltage stabilizing circuit, and voltage stabilizing processing is carried out on a driving signal input to the switching circuit, so that the voltage stabilizing precision of the voltage stabilizing circuit is improved, and the risk of damaging the switching tube in the switching circuit is reduced; the voltage value of the voltage-stabilizing signal can be adjusted, so that the practicability of the self-driven synchronous rectification circuit is improved; the leakage current of the voltage stabilizing circuit under the high-temperature condition is avoided, and the reliability and the stability of the voltage stabilizing circuit are improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a self-driven synchronous rectification circuit provided in an embodiment of the present application;
FIG. 2 is a schematic structural diagram of another self-driven synchronous rectification circuit provided in an embodiment of the present application;
fig. 3 is a schematic structural diagram of another self-driven synchronous rectification circuit provided in an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, 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 application.
In the description of the present application, it is to be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In the description of the present application, it is noted that, unless explicitly stated or limited otherwise, "including" and "having" and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art. Further, in the description of the present application, "a plurality" means two or more unless otherwise specified. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
The present application will be described in detail with reference to specific examples.
As shown in fig. 1, a schematic structural diagram of a self-driving synchronous rectification circuit provided in an embodiment of the present application includes: the transformer 101, the first switch circuit 102, the second switch circuit 103, the first dc blocking circuit 105, the second dc blocking circuit 104, the first regulator circuit 107, the second regulator circuit 106, and the load circuit 108. The transformer 101 includes a primary winding 13, a first secondary winding 34, and a second secondary winding 56, wherein a different name end of the first secondary winding 34 is connected to a same name end of the second secondary winding 56.
The first direct current isolation circuit 105 is connected with the different name end of the second secondary side coil 56, the first voltage stabilizing circuit 107 is connected with the first direct current isolation circuit 105, the first voltage stabilizing circuit 107 is connected with the first switch circuit 102, the second direct current isolation circuit 104 is connected with the same name end of the first secondary side coil 34, the second voltage stabilizing circuit 106 is connected with the second direct current isolation circuit 104, the second voltage stabilizing circuit 106 is connected with the second switch circuit 103, and the load circuit 18 is connected with the different name end of the first secondary side coil 34.
The transformer 101 can be understood as a power transformer that transforms and divides the voltage of the alternating current provided by the power supply, and turns on the alternating current in the same period by matching at least two secondary windings with the voltage stabilizing circuit, and outputs the alternating current to the switching circuit for rectification and then provides the direct current to the load, for example: ZSS, ZS series power transformer. In the embodiment of the present application, the primary winding 13, the first secondary winding 34, and the second secondary winding 56 are made of oxygen-free copper wires with high conductivity, and the winding windings are made of cylindrical or double-pancake structures, so that the structure of the transformer 101 is more compact, and the main insulation is improved.
In the embodiment of the present application, the synonym end of the first secondary winding 34 of the transformer 101 is connected to the synonym end of the second secondary winding 56, and when the synonym end of the primary winding 12 of the transformer 101 is a positive pulse ac, the synonym end 3 of the first secondary winding 34 outputs a high level, and the synonym end 6 of the second secondary winding 56 outputs a low level; when the dotted terminal of the primary winding 12 of the transformer 101 is the reverse pulse ac, the dotted terminal 3 of the first secondary winding 34 outputs a low level, and the dotted terminal 6 of the second secondary winding 56 outputs a high level.
In one embodiment of the application, the turn ratio of the primary coil 12 and the first secondary coil 34 is calculated according to the following formula:
N＝V/(Vf+V0)；
where N represents the turn ratio of the primary coil 12 to the first secondary coil 34, V represents the input voltage, V representsfRepresenting the value of the output voltage, V0Representing a preset voltage value.
For example, the input voltage V is 220V, and the output voltage V isf30V, preset voltage V0The turn ratio N of the primary coil 12 and the first secondary coil 34 is equal to 0.4V, which is approximately equal to 7.
In one embodiment, a heat sink plate is disposed below the transformer 101. The heat sink plate may be understood as a heat dissipating element that provides a heat dissipating condition for the transformer 101. In this embodiment, four positioning holes are disposed at four corners of the heat dissipation plate, the transformer 101 is fixed on the heat dissipation plate by means of bolts, and a heat conduction plate is disposed between the heat dissipation plate and the transformer 101 to conduct heat generated by the transformer 101 to the heat dissipation plate. The inner cavity of the heat dissipation plate is filled with heat dissipation liquid, and the heat dissipation liquid is preferably ethanol. The working principle of the heat dissipation plate is that when the transformer 101 continuously works to generate heat, the ethanol quickly absorbs the heat of the transformer 101 to volatilize, and when the ethanol gas touches the inner cavity wall of the heat dissipation plate with lower temperature, the ethanol gas is condensed into ethanol heat dissipation liquid, so that the heat generated when the transformer 101 works is reduced in a circulating and reciprocating manner.
The beneficial effects brought by the technical scheme provided by some embodiments of the application at least comprise: the heat generated by the transformer is guided to the inner cavity of the heat dissipation plate through the heat conduction plate, and heat exchange is carried out between the inner cavity of the heat dissipation plate and the ethanol, so that the transformer can be effectively cooled, the working efficiency of the transformer is guaranteed, and the service life and the reliability of the transformer are improved.
The first switch circuit 102 and the second switch circuit 103 are understood to transmit the direct current obtained by rectifying the alternating current transmitted by the transformer 101 to the load circuit, and the main components are switch tubes.
The first dc blocking circuit 105 and the second dc blocking circuit 104 may be understood as a circuit for filtering the ac power from the transformer 101 to dc pollution, such as an RC circuit. In the embodiment of the present application, the first dc blocking circuit 105 is connected to the synonym terminal 6 of the second secondary winding 56, receives the first signal from the second secondary winding 56, performs dc blocking processing to obtain a first processed signal, and transmits the first processed signal to the first voltage stabilizing circuit 107; the second dc blocking circuit 104 is connected to the dotted terminal 3 of the first secondary coil 34, receives the second signal from the first secondary coil 56, performs dc blocking processing to obtain a second processed signal, and transmits the second processed signal to the second voltage stabilizing circuit 106.
The first voltage stabilizing circuit 107 and the second voltage stabilizing circuit 106 can be understood as circuits for performing voltage stabilizing processing on processed signals from the dc blocking circuit, and the main components are a switching tube and a voltage regulator tube, which includes but is not limited to a voltage regulator diode. The three-end adjustable shunt reference source has good thermal stability, is matched with an adjustable resistor to adjust any voltage value of an output voltage value between 2.5V and 36V, and is provided with a control electrode, an anode and a cathode.
The load circuit 108 may be understood as a circuit that receives a direct current and drives various components to operate, for example: backlight light bar circuits, protection circuits, circuits containing multiple processors, etc. in televisions.
In this embodiment, the working flow of the self-driven synchronous rectification circuit provided by the present application is:
when the dotted terminal of the primary winding 12 of the transformer 101 is reverse pulse alternating current, the dotted terminal 3 of the first secondary winding 34 outputs low level, and the dotted terminal 6 of the second secondary winding 56 outputs high level; the second switching circuit 103 is in a standby state; the first dc blocking circuit 105 performs dc blocking processing on the first signal from the second secondary winding 56 to obtain a first processed signal, transmits the first processed signal to the first voltage stabilizing circuit 107, and the first voltage stabilizing circuit 107 performs voltage stabilizing processing on the first processed signal to obtain a first driving signal, and transmits the first driving signal to the first switching circuit 102; the first driving signal is used to make the first switch circuit 102 in an operating state, so that the first switch circuit 102, the first sub-coil 34 and the load circuit 108 form a loop.
When the dotted terminal of the primary winding 12 of the transformer 101 is the positive pulse alternating current, the dotted terminal 3 of the first secondary winding 34 outputs a high level, and the dotted terminal 6 of the second secondary winding 56 outputs a low level; the first switching circuit 102 is in a standby state; the second dc blocking circuit 104 performs dc blocking processing on the second signal from the first secondary winding 34 to obtain a second processed signal, transmits the second processed signal to the second voltage stabilizing circuit 106, and the second voltage stabilizing circuit 106 performs voltage stabilizing processing on the second processed signal to obtain a second driving signal, and transmits the second driving signal to the second switching circuit 103; the second driving signal is used to make the second switching circuit in a working state, so that the second switching circuit, the second secondary winding, and the load circuit 108 form a loop.
After the ac power from the power supply is rectified by the self-driven synchronous rectification circuit, dc power is supplied to the load circuit 108 to keep the load circuit 108 in an operating state.
The beneficial effects brought by the technical scheme provided by some embodiments of the application at least comprise: the three-terminal adjustable shunt reference source is used as a voltage stabilizing tube of the voltage stabilizing circuit, and voltage stabilizing processing is carried out on a driving signal input to the switching circuit, so that the voltage stabilizing precision of the voltage stabilizing circuit is improved, and the risk of damaging the switching tube in the switching circuit is reduced; the voltage value of the voltage-stabilizing signal can be adjusted, so that the practicability of the self-driven synchronous rectification circuit is improved; the leakage current of the voltage stabilizing circuit under the high-temperature condition is avoided, and the reliability and the stability of the voltage stabilizing circuit are improved.
As shown in fig. 2, a schematic structural diagram of another self-driven rectifier circuit provided in the embodiment of the present application includes: the circuit comprises a transformer 101, a first switch circuit 102, a second switch circuit 103, a first DC blocking circuit 105, a second DC blocking circuit 104, a first voltage stabilizing circuit 107, a second voltage stabilizing circuit 106, a load circuit 108, a first current limiting circuit 110 and a second current limiting circuit 109. The transformer 101 includes a primary winding 13, a first secondary winding 34, and a second secondary winding 56, wherein a different name end of the first secondary winding 34 is connected to a same name end of the second secondary winding 56.
The first direct current isolation circuit 105 is connected with the different name end of the second secondary side coil 56, the first voltage stabilizing circuit 107 is connected with the first direct current isolation circuit 105, the first voltage stabilizing circuit 107 is connected with the first current limiting circuit 110, the first current limiting circuit 110 is connected with the first switch circuit 102, the second direct current isolation circuit 104 is connected with the same name end of the first secondary side coil 34, the second voltage stabilizing circuit 106 is connected with the second direct current isolation circuit 104, the second voltage stabilizing circuit 106 is connected with the second current limiting circuit 109, the second current limiting circuit 109 is connected with the second switch circuit 103, and the load circuit 18 is connected with the different name end of the first secondary side coil 34.
The working principle of the transformer 101, the first switch circuit 102, the second switch circuit 103, the first dc blocking circuit 105, the second dc blocking circuit 104, the first voltage stabilizing circuit 107, the second voltage stabilizing circuit 106 and the load circuit 108 is described in detail in fig. 1.
The first current limiting circuit 110 is used to limit the current value of the second voltage stabilizing circuit 106, and the main component is a current limiting resistor, and the voltage drop of the current limiting resistor is ignored. The second current limiting circuit 109 is configured to limit a current value of the first voltage stabilizing circuit 107, and the main component is a current limiting resistor, and a voltage drop of the second current limiting circuit is negligible.
The beneficial effects brought by the technical scheme provided by some embodiments of the application at least comprise: the first voltage stabilizing circuit and the second voltage stabilizing circuit are subjected to current limiting protection by utilizing the first current limiting circuit and the second current limiting circuit, so that the phenomenon that the current in the first voltage stabilizing circuit and the second voltage stabilizing circuit is too large and damages a switch tube and a three-terminal adjustable shunt reference source in the voltage stabilizing circuit are caused is avoided, and the reliability of the voltage stabilizing circuit is improved.
As shown in fig. 3, a schematic structural diagram of another self-driven synchronous rectification circuit provided in the embodiment of the present application includes: the circuit comprises a transformer 101, a first switch circuit 102, a second switch circuit 103, a first DC blocking circuit 105, a second DC blocking circuit 104, a first voltage stabilizing circuit 107, a second voltage stabilizing circuit 106, a load circuit 108, a first current limiting circuit 110 and a second current limiting circuit 109. The transformer 101 includes a primary winding 13, a first secondary winding 34, and a second secondary winding 56, wherein a different name end of the first secondary winding 34 is connected to a same name end of the second secondary winding 56.
The first stabilizing circuit 107 includes: the circuit comprises a first adjustable resistor RL1, a second adjustable resistor RL2, a first capacitor C1, a first switch tube Q1, a first resistor R1 and a first three-terminal adjustable shunt reference source U1. The first three-terminal adjustable shunt reference source U1 includes a first pin, a second pin, and a third pin.
An emitter of the first switch tube Q1 is connected to a first end of a second adjustable resistor RL2, a second end of the second adjustable resistor RL2 is connected to a first capacitor C1, a second end of the first capacitor C1 is connected to a base of the first switch tube Q1, a first pin of a first three-terminal adjustable shunt reference source U1 is connected to a first end of the first adjustable resistor RL1, a second pin of the first three-terminal adjustable shunt reference source U1 is connected to a base of the first switch tube Q1, a third pin of the first three-terminal adjustable shunt reference source U1 is connected to a second end of the first adjustable resistor RL1, a second end of the first adjustable resistor RL2 is grounded, a first end of the first resistor R1 is connected to a base of the first switch tube Q1, and a second end of the first resistor R1 is connected to a collector of the first switch tube Q1.
The second stabilizing circuit 106 further includes: the three-terminal adjustable shunt reference source comprises a third adjustable resistor RL3, a fourth adjustable resistor RL4, a second capacitor C2, a second switch tube Q2, a second resistor R2 and a second three-terminal adjustable shunt reference source U2. The second three-terminal adjustable shunt reference source U2 includes a first pin, a second pin, and a third pin.
An emitter of the second switching tube Q2 is connected to a first end of a fourth adjustable resistor RL4, a second end of the fourth adjustable resistor RL4 is connected to a second capacitor C2, a second end of the second capacitor C2 is connected to a base of the second switching tube Q2, a first pin of a second three-terminal adjustable shunt reference source U2 is connected to a first end of the third adjustable resistor RL3, a second pin of the second three-terminal adjustable shunt reference source U2 is connected to a base of the second switching tube Q2, a third pin of the second three-terminal adjustable shunt reference source U2 is connected to a second end of the third adjustable resistor RL3, a second end of the third adjustable resistor RL3 is grounded, a first end of the second resistor R2 is connected to a base of the second switching tube Q2, and a second end of the second resistor R2 is connected to a collector of the second switching tube Q2.
The first dc blocking circuit 105 includes: a third capacitor C3 and a third resistor R3.
A first end of the third capacitor C3 is connected to the synonym terminal 6 of the second secondary winding 56, a first end of the third resistor R3 is connected to a first end of the third capacitor C3, a second end of the third resistor R3 is connected to a second end of the third capacitor C3, and a second end of the third capacitor C3 is connected to a collector of the first switching tube Q1.
The second dc blocking circuit 104 includes: a fourth capacitor C4 and a fourth resistor R4.
A first end of the fourth capacitor C4 is connected to the dotted terminal 3 of the first sub-coil 34, a first end of the fourth resistor R4 is connected to a first end of the fourth capacitor C4, a second end of the fourth resistor R4 is connected to a second end of the fourth capacitor C4, and a second end of the fourth capacitor C4 is connected to a collector of the second switch Q2.
The first current limiting circuit 110 includes: and a fifth resistor R5. A first terminal of the fifth resistor R5 is connected to the emitter of the first switch Q1, and a second terminal of the fifth resistor R5 is connected to the gate of the third switch Q3.
The second current limit current 109 includes: a sixth resistor R6. A first terminal of the sixth resistor R6 is connected to the emitter of the second switch transistor Q2, and a second terminal of the sixth resistor R6 is connected to the gate of the fourth switch transistor Q4. The first switching circuit 102 includes: a third switch tube Q3 and a seventh resistor R7.
The drain of the third switching tube Q3 is connected to the dotted terminal 3 of the first secondary winding 34, the source of the third switching tube Q3 is grounded, the gate of the third switching tube Q3 is connected to the second terminal of the fifth resistor R5, the first terminal of the seventh resistor R7 is connected to the gate of the third switching tube Q3, and the second terminal of the seventh resistor R7 is grounded.
The second switch circuit 103 includes: a fourth switching tube Q4 and an eighth resistor R8;
the drain of the fourth switching tube Q4 is connected to the synonym terminal 6 of the second secondary winding 56, the source of the fourth switching tube Q4 is grounded, the gate of the fourth switching tube Q4 is connected to the second terminal of the sixth resistor R6, the first terminal of the eighth resistor R8 is connected to the gate of the fourth switching tube Q4, and the second terminal of the eighth resistor R8 is grounded.
In one embodiment, the first switching transistor Q1 and the second switching transistor Q2 are NPN transistors, and the third switching transistor Q3 and the fourth switching transistor Q4 are MOS transistors.
The working principle of the self-driven synchronous rectification circuit provided by the embodiment of the application is illustrated as follows:
when the dotted terminal of the primary winding 12 of the transformer 101 is reverse pulse alternating current, the dotted terminal 3 of the first secondary winding 34 outputs low level, and the dotted terminal 6 of the second secondary winding 56 outputs high level; the collector of the second switch tube Q2 connected to the end 3 with the same name is at low level, the second switch tube Q2 is in standby state, and the second drive signal is stopped being sent; the fourth switching tube Q4 connected with the second switching tube Q2 is in a standby state; a third capacitor C3 connected with the different name terminal 6 is used for carrying out DC blocking treatment on the power voltage input by the transformer, and a third resistor R3 protects a third capacitor C3; the first resistor R1 divides voltage, and the second pin of the first three-terminal adjustable shunt reference source U1 always outputs working voltage VU1When the collector of the first switching tube Q1 is at a high level, the standby state is switched to a working state, the emitter outputs a first driving voltage, the fifth resistor R5 is used for current limiting protection, the resistance value is 1-4.7 Ω, and the voltage drop of the first driving voltage is ignored; the voltage value V1 of the first driving voltage refers to the following formula:
V1＝(RL2/RL1+1)×VU1；
wherein R isL2Is the resistance value, R, of the second adjustable resistor RL2L1Is the resistance value of the first adjustable resistor RL 1;
the first driving voltage is loaded on the grid electrode of the third switching tube Q3, and after the voltage is divided by the seventh resistor R7, the third switching tube Q3 is conducted; the third switching tube Q3, the first secondary winding 34 and the load circuit 108 form a loop, and the load circuit 108 is in a working state;
when the same-name terminal of the primary winding 12 of the transformer 101 is a positive-direction pulse alternating current, the first secondary winding 34The homonymous terminal 3 outputs a high level, and the heteronymous terminal 6 of the second secondary coil 56 outputs a low level; the collector of the first switch tube Q1 connected with the different name terminal 6 is low level, the first switch tube Q1 is in standby state, and stops sending the first driving signal; the third switching tube Q3 connected with the first switching tube Q1 is in a standby state; a fourth capacitor C4 connected with the same-name terminal 3 is used for carrying out DC blocking treatment on the power voltage input by the transformer, and a fourth resistor R4 protects a fourth capacitor C4; the second resistor R2 divides voltage, and the second pin of the second three-terminal adjustable shunt reference source U2 always outputs working voltage VU2When the collector of the second switching tube Q2 is at a high level, the standby state is switched to a working state, the emitter outputs a first driving voltage, the sixth resistor R6 is used for current limiting protection, the resistance value is 1-4.7 Ω, and the voltage drop of the first driving voltage is ignored; the voltage value V2 of the second driving voltage refers to the following equation:
V2＝(RL4/RL3+1)×VU2；
wherein RL4 is the resistance of the fourth adjustable resistor RL4, and RL3 is the resistance of the third adjustable resistor RL 3;
the second driving voltage is loaded on the grid electrode of the fourth switching tube Q4, and after the voltage is divided by the eighth resistor R8, the fourth switching tube Q4 is switched on; the fourth switching tube Q4, the second secondary winding 56, and the load circuit 108 form a loop, and the load circuit 108 is in an operating state.
From the above analysis, the output voltage of the driving voltage signals of the third switching tube and the fourth switching tube is determined by the adjustable resistors RL1, RL2, RL3 and RL4 and the three-terminal adjustable shunt reference source under any output voltage condition, so that the voltage value of the driving voltage does not exceed the gate voltage range of the third switching tube and the fourth switching tube, and the voltage value range of the driving voltage can be adjusted by changing the resistance values of the adjustable resistors RL1, RL2, RL3 and RL 4.
The beneficial effects brought by the technical scheme provided by some embodiments of the application at least comprise: the three-terminal adjustable shunt reference source is used as a voltage stabilizing tube of the voltage stabilizing circuit, and voltage stabilizing processing is carried out on a driving signal input to the switching circuit, so that the voltage stabilizing precision of the voltage stabilizing circuit is improved, and the risk of damaging the switching tube in the switching circuit is reduced; the voltage value of the voltage-stabilizing signal can be adjusted, so that the practicability of the self-driven synchronous rectification circuit is improved; the leakage current of the voltage stabilizing circuit under the high-temperature condition is avoided, and the reliability and the stability of the voltage stabilizing circuit are improved.
The above disclosure is only for the purpose of illustrating the preferred embodiments of the present application and is not to be construed as limiting the scope of the present application, so that the present application is not limited thereto, and all equivalent variations and modifications can be made to the present application.
Claims (9)
1. A self-driven synchronous rectifier circuit, comprising: the transformer, the first switch circuit, the second switch circuit, the first voltage stabilizing circuit, the first DC isolating circuit, the second voltage stabilizing circuit, the second DC isolating circuit and the load circuit;
the transformer includes: the primary side coil, the first secondary side coil and the second secondary side coil; the synonym end of the first secondary side coil is connected with the synonym end of the second secondary side coil;
the first voltage stabilizing circuit comprises a first three-terminal adjustable shunt reference source, and the second voltage stabilizing circuit comprises a second three-terminal adjustable shunt reference source;
the first switch circuit is connected with the homonymous end of the first secondary side coil, and the second switch circuit is connected with the synonym end of the second secondary side coil;
the first direct current isolating circuit is connected with the synonym end of the second secondary side coil, the first voltage stabilizing circuit is connected with the first direct current isolating circuit, and the first voltage stabilizing circuit is connected with the first switch circuit;
the second direct current isolating circuit is connected with the dotted terminal of the first secondary side coil, the second voltage stabilizing circuit is connected with the second direct current isolating circuit, and the second voltage stabilizing circuit is connected with the second switch circuit;
the load circuit is connected with the synonym end of the first secondary side coil;
the first direct current blocking circuit performs direct current blocking processing on a first signal from the second secondary coil to obtain a first processing signal, transmits the first processing signal to the first voltage stabilizing circuit, performs voltage stabilizing processing on the first processing signal by the first voltage stabilizing circuit to obtain a first driving signal, and transmits the first driving signal to the first switching circuit; the first driving signal is used for enabling the first switching circuit to be in a working state, so that the first switching circuit, the first secondary coil and the load circuit form a loop;
the second direct current blocking circuit performs direct current blocking processing on a second signal from the first secondary coil to obtain a second processing signal, transmits the second processing signal to the second voltage stabilizing circuit, performs voltage stabilizing processing on the second processing signal by the second voltage stabilizing circuit to obtain a second driving signal, and transmits the second driving signal to the second switching circuit; the second driving signal is used for enabling the second switching circuit to be in a working state, so that the second switching circuit, the second secondary coil and the load circuit form a loop.
2. The self-driven synchronous rectification circuit of claim 1, wherein the first voltage regulation circuit further comprises: the circuit comprises a first adjustable resistor, a second adjustable resistor, a first capacitor, a first switch tube and a first resistor;
the first three-end adjustable shunt reference source comprises a first pin, a second pin and a third pin;
an emitting electrode of the first switch tube is connected with a first end of the second adjustable resistor, a second end of the second adjustable resistor is connected with the first capacitor, and a second end of the first capacitor is connected with a base electrode of the first switch tube;
a first pin of the first three-terminal adjustable shunt reference source is connected with a first end of the first adjustable resistor, a second pin of the first three-terminal adjustable shunt reference source is connected with a base electrode of the first switching tube, a third pin of the first three-terminal adjustable shunt reference source is connected with a second end of the first adjustable resistor, and the second end of the first adjustable resistor is grounded;
the first end of the first resistor is connected with the base electrode of the first switching tube, and the second end of the first resistor is connected with the collector electrode of the first switching tube;
the second voltage stabilizing circuit further comprises: the first adjustable resistor, the second adjustable resistor, the third capacitor, the fourth capacitor, the second switch tube and the second resistor are connected in series;
an emitting electrode of the second switching tube is connected with a first end of the fourth adjustable resistor, a second end of the fourth adjustable resistor is connected with the second capacitor, and a second end of the second capacitor is connected with a base electrode of the second switching tube;
a first pin of the second three-terminal adjustable shunt reference source is connected with a first end of the third adjustable resistor, a second pin of the second three-terminal adjustable shunt reference source is connected with a base electrode of the second switching tube, a third pin of the second three-terminal adjustable shunt reference source is connected with a second end of the third adjustable resistor, and the second end of the third adjustable resistor is grounded;
the first end of the second resistor is connected with the base electrode of the second switch tube, and the second end of the second resistor is connected with the collector electrode of the second switch tube.
3. The self-driven synchronous rectification circuit of claim 2, wherein the first dc removal circuit comprises: a third capacitor and a third resistor;
the first end of the third capacitor is connected with the synonym end of the second secondary side coil, the first end of the third resistor is connected with the first end of the third capacitor, the second end of the third resistor is connected with the second end of the third capacitor, and the second end of the third capacitor is connected with the collector electrode of the first switching tube;
the second dc removal circuit includes: a fourth capacitor and a fourth resistor;
the first end of the fourth capacitor is connected with the dotted end of the first secondary coil, the first end of the fourth resistor is connected with the first end of the fourth capacitor, the second end of the fourth resistor is connected with the second end of the fourth capacitor, and the second end of the fourth capacitor is connected with the collector electrode of the second switch tube.
4. The self-driven synchronous rectification circuit according to claim 2, wherein the first switching circuit comprises: a third switching tube and a seventh resistor;
the drain electrode of the third switching tube is connected with the dotted terminal of the first secondary coil, the source electrode of the third switching tube is grounded, the grid electrode of the third switching tube is connected with the first voltage stabilizing circuit, the first end of the seventh resistor is connected with the grid electrode of the third switching tube, and the second end of the seventh resistor is grounded;
the second switching circuit includes: a fourth switching tube and an eighth resistor;
the drain of the fourth switch tube is connected with the synonym end of the second secondary coil, the source of the fourth switch tube is grounded, the grid of the fourth switch tube is connected with the second voltage stabilizing circuit, the first end of the eighth resistor is connected with the grid of the fourth switch tube, and the second end of the eighth resistor is grounded.
5. The self-driven synchronous rectification circuit according to claim 4, further comprising: a first current limiting circuit and a second current limiting circuit;
the first current limiting circuit is connected with the first voltage stabilizing circuit, and the second current limiting circuit is connected with the second voltage stabilizing circuit.
6. The self-driven synchronous rectification circuit of claim 5, wherein the first current limiting circuit comprises: a fifth resistor;
the first end of the fifth resistor is connected with the emitter of the first switching tube, and the second end of the fifth resistor is connected with the grid of the third switching tube;
the second current limiting current includes: a sixth resistor;
and the first end of the sixth resistor is connected with the emitter of the second switching tube, and the second end of the sixth resistor is connected with the grid of the fourth switching tube.
7. The self-driven synchronous rectification circuit according to any one of claims 2 to 6, wherein the first switching tube comprises a first NPN transistor, and the second switching tube comprises a second NPN transistor.
8. The self-driven synchronous rectification circuit according to claim 1, wherein a turn ratio of the primary coil and the first secondary coil is expressed as:
N＝V/(Vf+V0)；
wherein N represents a turn ratio of the primary coil and the first secondary coil, V represents an input voltage value, and V representsfRepresenting the value of the output voltage, V0Representing a preset voltage value.
9. The self-driven synchronous rectification circuit according to claim 1, further comprising: a heat dissipation plate; the inner cavity of the heat dissipation plate is filled with heat dissipation liquid;
four positioning holes are formed in four corners of the heat dissipation plate and used for fixing the transformer, and a heat conduction plate is arranged between the heat dissipation plate and the transformer.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022921433.4U CN216390803U (en) | 2020-12-08 | 2020-12-08 | Self-driven synchronous rectification circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022921433.4U CN216390803U (en) | 2020-12-08 | 2020-12-08 | Self-driven synchronous rectification circuit |
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| CN216390803U true CN216390803U (en) | 2022-04-26 |
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