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WO2018161748A1 - Alimentation à découpage de type à accumulation - Google Patents

Alimentation à découpage de type à accumulation Download PDF

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Publication number
WO2018161748A1
WO2018161748A1 PCT/CN2018/074968 CN2018074968W WO2018161748A1 WO 2018161748 A1 WO2018161748 A1 WO 2018161748A1 CN 2018074968 W CN2018074968 W CN 2018074968W WO 2018161748 A1 WO2018161748 A1 WO 2018161748A1
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Prior art keywords
primary winding
capacitor
diode
winding
power supply
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PCT/CN2018/074968
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English (en)
Chinese (zh)
Inventor
王保均
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Mornsun Guangzhou Science and Technology Ltd
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Mornsun Guangzhou Science and Technology Ltd
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    • 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

Definitions

  • the invention relates to the field of switching power supplies, and in particular to a flyback switching power supply.
  • the switching power supply is widely used.
  • the fly-back switching power supply has a beautiful advantage: the circuit
  • the topology is simple and the input voltage range is wide. Since the number of components is small, the reliability of the circuit is relatively high, so the application is wide.
  • many documents are also known as flyback switching power supplies, flyback power supplies, and flyback converters. In Japan and Taiwan, they are also called flyback converters, flyback switching power supplies, and flyback power supplies.
  • a common topology for an AC/DC converter is shown in Figure 1. The prototype is from the "Switching Power Supply Converter Topology and Design" by Dr. Zhang Xingzhu, ISBN 978-7-5083-9015-4.
  • the rectifier bridge 101, the filter circuit 200, and the basic flyback topology unit circuit 300 are also referred to as the main power stage.
  • the practical circuit is also provided with a varistor, an NTC thermistor, and an EMI (Electromagnetic Interference) in front of the rectifier bridge. ) Protect the circuit to ensure that the electromagnetic compatibility of the flyback power supply meets the requirements for use.
  • the flyback switching power supply requires that the leakage inductance between the primary and secondary windings is as small as possible, so that the conversion efficiency is high, and the withstand voltage of the primary side main power switch tube is also lowered, and the RCD network is used as the demagnetization and absorption counter.
  • RCD absorption refers to the absorption circuit composed of resistors, capacitors and diodes.
  • the literature in China is the same as the international one.
  • the letter R is used to give the resistance number and represents the resistance.
  • the letter C is used to number the capacitor and represent the capacitor.
  • the letter D is used to give the diode. Numbered and represents the diode, the resistor and capacitor are connected in parallel, and then connected in series with the diode to form an RCD network.
  • the rectifier bridge 101 is generally composed of four rectifier diodes. When there is no rectifier bridge 101, 200, 300 can constitute a DC/DC switching power supply or converter. Because it is DC power supply, there is no power factor requirement, and the power can be 75W. the above. In fact, the use of a flyback topology in a low-voltage DC/DC switching power supply is not mainstream. This is because at low voltage, the input current of the flyback switching power supply is discontinuous and the ripple is large, which requires more power supply equipment.
  • the output current is not continuous, the ripple is large, and the capacity of the subsequent filter capacitor is high; especially when the input voltage is low, since the excitation current becomes larger, the primary winding has to be wound with multiple strands;
  • the inductance of the side winding is also low. It is often found that the calculated number of turns cannot be tiled to the left to the right of the slot of the full frame. Especially when the working voltage is high, the sandwich series winding method can be used. Next, it is forced to adopt the sandwich parallel winding method. Since the two primary windings are not in the same layer, there is a leakage inductance between the two primary windings, and the leakage inductance will cause loss, thereby making the switching power supply less efficient. The problem caused by the leakage inductance between two parallel primary windings:
  • the advantage is non-destructive demagnetization, the efficiency is higher, but the choice of the wire diameter of the third winding is also a problem: the selection is relatively thin, and the winding of the primary winding is more troublesome, easy to put The thin wire is broken; if the same wire diameter is selected as the primary winding, the cost is high.
  • the third winding demagnetization flyback converter is also referred to as a "three-winding absorption flyback converter".
  • Low-voltage DC/DC switching power supplies generally refer to input voltages below 48V. Some low-voltage DC/DC switching power supplies can operate up to 160V DC, such as railway power supplies.
  • the present invention solves the shortcomings of the existing low-voltage flyback switching power supply, and provides a flyback switching power supply.
  • the primary winding can be used without the need of two separate parallel connections, that is, the primary secondary winding can be allowed.
  • the leakage inductance between the two is large, and the third winding is not used for demagnetization, and the conversion efficiency is not lowered, and the loss during excitation and demagnetization is reduced.
  • a flyback switching power supply including a transformer, an N-channel FET, a second capacitor, a first diode, a second diode, and a transformer including a first primary side
  • the winding, the second primary winding and the secondary winding, the secondary winding opposite end is connected to the second diode anode
  • the second diode cathode is connected to one end of the second capacitor, and forms an output positive
  • the secondary winding has the same name end Connected to the other end of the second capacitor and formed an output negative
  • the positive terminal of the input DC power supply is simultaneously connected with the same name end of the first primary winding, the cathode of the first diode, the first primary winding different name end and the N channel field
  • the drain of the effect transistor is connected;
  • the anode of the first diode is connected to the opposite end of the second primary winding, the source of the N-channel FET is connected to the same end of the second primary winding, and the connection point is simultaneously connected to the input
  • first primary winding and the second primary winding are two-wire winding, and further comprising a first capacitor, one end of the first capacitor and the first The primary winding is connected to the different name, the first electric The other end of the capacitor is connected to the opposite end of the second primary winding.
  • a flyback switching power supply includes a transformer, an N-channel FET, a second capacitor, and a first diode. a tube, a second diode, the transformer comprises a first primary winding, a second primary winding and a secondary winding, the secondary winding opposite end is connected to the second diode anode, the second diode cathode and the second One end of the capacitor is connected and forms an output positive, the same-side end of the secondary winding is connected to the other end of the second capacitor, and the output is negative; the positive terminal of the input DC power supply is different from the drain of the N-channel FET and the second primary winding.
  • the terminals are connected, the source of the N-channel FET is connected to the same name end of the first primary winding; the second-side winding has the same name end connected to the cathode of the first diode, and the first primary winding has a different name and the first end
  • the anode of the diode is connected, the connection point is simultaneously connected to the negative terminal of the input DC power supply; the gate of the N-channel FET is connected with the control signal; and the first primary winding and the second primary winding are double-wired and wound
  • the invention also provides a technical scheme using a P-channel field effect tube.
  • the polarity of the power source, the diode and the same name end are reversed (the output rectification part does not need to be reversed), then the scheme 3: an inverse is obtained.
  • the excitation switching power supply comprises a transformer, a P-channel FET, a second capacitor, a first diode, a second diode, and the transformer comprises a first primary winding, a second primary winding and a secondary winding,
  • the second side of the secondary winding is connected to the anode of the second diode
  • the cathode of the second diode is connected to one end of the second capacitor, and the output is positive
  • the end of the secondary winding is connected with the other end of the second capacitor, and the output is negative.
  • the negative terminal of the input DC power source is simultaneously connected to the opposite end of the first primary winding and the anode of the first diode, and the first primary winding has the same name end connected to the drain of the P channel FET; the first diode The cathode is connected to the same end of the second primary winding, the source of the P-channel FET is connected to the second end of the second primary winding, and the connection point is simultaneously connected to the positive terminal of the input DC power supply; the gate connection of the P-channel FET control signal;
  • the first primary winding and the second primary winding are two-wire winding, and further comprise a first capacitor, one end of the first capacitor is connected to the same end of the first primary winding, and the other end of the first capacitor is The two primary windings are connected to the same name end.
  • a flyback switching power supply includes a transformer, a P-channel FET, a second capacitor, a first diode, and a second diode.
  • the transformer comprises a first primary winding, a second primary winding and a secondary winding, the secondary winding opposite end is connected to the second diode anode, and the second diode cathode is connected to one end of the second capacitor and forms an output positive
  • the secondary winding has the same name end connected to the other end of the second capacitor, and forms an output negative; the negative terminal of the input DC power supply is simultaneously connected with the drain of the P channel field effect transistor and the same end of the second primary winding, and the P channel field effect transistor
  • the source is connected to the first name of the first primary winding; the second end of the second winding is connected to the anode of the first diode, and the first end of the first winding is connected to the cathode of the first diode, and is connected Point simultaneously Connected to the positive terminal of the input DC power supply; the gate of the P-channel FET is connected to the control signal; the first primary winding and the second primary winding are wound in a double line, and further includes a
  • the first primary winding and the second primary winding have the same wire diameter.
  • the second primary winding participates in the excitation by the first capacitance.
  • the physical path of the excitation current of the first primary winding and the second primary winding is reversed in the PCB layout.
  • the beneficial effects of the invention are as follows: the leakage inductance between the primary and secondary windings is allowed to be large, and the primary side is still wound by two wires, the conversion efficiency is high, and the EMI performance is very good.
  • FIG. 1 is a schematic diagram of a conventional flyback switching power supply for alternating current to direct current
  • FIG. 2 is a schematic diagram of a first embodiment of a flyback switching power supply scheme according to the present invention
  • 2-1 is a schematic diagram of charging the capacitor C1 at the time of power-on in the first embodiment
  • FIG. 2-2 is a schematic diagram showing voltage polarities of charging of capacitor C1 after power-on in the first embodiment
  • 2-3 is a schematic diagram of generating two excitation currents 41, 42 when Q1 is saturated in the first embodiment
  • 2-4 is a schematic diagram of the Q1 cutoff in the first embodiment, generating a freewheeling current 43 and a demagnetizing current 44;
  • FIG. 3 is a schematic diagram of a second embodiment of a flyback switching power supply scheme according to the present invention.
  • FIG. 4 is a schematic diagram of a third embodiment of a flyback switching power supply scheme according to the present invention.
  • FIG. 5 is a schematic diagram of a fourth embodiment of a flyback switching power supply scheme according to the present invention.
  • FIG. 2 is a schematic diagram of a flyback switching power supply according to a first embodiment of the present invention, including a transformer B, an N-channel FET Q1, a second capacitor C2, a first diode D1, and a second diode Tube D2, transformer B includes a first primary winding N P1 , a second primary winding N P2 and a secondary winding N S , the secondary winding N S different end is connected to the second diode D2 anode, the second diode the cathode end of diode D2 is connected to a second capacitor C2, and outputs the positive form, as in FIG Vout + terminal of the secondary winding N S dotted terminal connected to the other terminal of the second capacitor C2, and the formation of negative output as Vout in FIG.
  • DC input voltage U DC (hereinafter, also referred to as a direct current power source U DC, power source U DC, or U DC) while the positive terminal +, and the cathode terminal of the first primary winding N P1 of the same name of the first diode D1 Connected, the first primary winding N P1 is connected to the drain D of the N-channel field effect transistor Q1; the anode of the first diode D1 is connected to the second primary winding N P2 , N-channel field effect
  • the source S of the tube Q1 is connected to the same end of the second primary winding N P2 , and the connection point is simultaneously connected to the negative terminal of the input DC power supply U DC - the gate G of the N-channel FET Q1 Connecting the control signal; the first primary winding N P1 and the second primary winding N P2 are wound in a double line, and further includes a first capacitor C1, one end of the first capacitor C1 and the first primary winding N P1 The different ends are connected, and the other end
  • Heterogeneous end one end of the winding in the figure where there is no black mark
  • Control signal including various pulse waves such as PWM pulse width modulation signal and PFM pulse frequency modulation;
  • Transformer B the first primary winding N P1 and the second primary winding N P2 are in the figure, the cores are connected by a broken line, indicating that they are wound around a transformer and share the same core, not a separate transformer, just for The graphics are clear and the connection relationship is simple, and the drawing method in the figure is used.
  • the source of the N-channel FET Q1 is connected to the same end of the second primary winding N P2 , and the connection point is simultaneously connected to the negative terminal of the input DC power supply U DC - that is, the source of the FET Q1 is connected to the input DC.
  • the negative terminal of the power supply U DC - this does not exist directly in the actual application, because in the field of switching power supply, the analysis of the working principle of the basic topology will omit unnecessary factors.
  • the source of the FET is connected to a current sense resistor or a current transformer to detect the average current or peak current to implement various control strategies.
  • the current sense resistor or current transformer is connected to the source.
  • the current transformer can appear anywhere in the excitation circuit, such as the drain of a FET, such as the same or different end of the first primary winding, and the current transformer has a conventional primary side. It is also a Hall sensor that is a "wire" and a magnetic core transformer whose secondary side is a multi-turn coil.
  • the first primary winding N P1 The charging current is: flowing from the same name end to the different name end; the charging current of the second primary winding N P2 is: flowing from the different name end to the same name end; N P1 and N P2 are two lines and winding, the two currents are equal in magnitude The generated magnetic flux is reversed and completely canceled. That is, at the time of power-on, the power supply U DC charges C1 through the two windings of the transformer B. These two windings cancel out due to mutual inductance, and do not work, and C1 is equivalent to passing N P1 and The DC internal resistance of N P2 is connected in parallel with the power supply U DC , and C1 still functions as power supply filtering and decoupling;
  • the terminal voltage of C1 is equal to the voltage of U DC , and the left is right and the right is negative, as shown in Figure 2-2.
  • Q1 When Q1 receives the control signal normally, taking one cycle as an example, when the gate of Q1 is high, Q1 is saturated and its internal resistance is equal to the on-state internal resistance R ds(ON) . For the convenience of analysis, this is the case. It is regarded as straight through, which is a wire. As shown in Figure 2-3, D1 is in a reverse bias state and does not participate in the work; at this time, two excitation currents are generated, as shown by 41 and 42 in Figure 2-3;
  • the current 41 is: the positive end of the power supply U DC passes through the same name end of the first primary winding N P1 , the different name of N P1 is output, the drain of Q1 enters, the source of Q1 is out, and returns to the negative end of the power supply U DC ;
  • the current 42 is: the left positive end of the capacitor C1 enters through the drain of Q1, the source of Q1 is out, and then enters through the same name of the second primary winding N P2 , the different name of N P2 is terminated, and the capacitor C1 is right negative. end;
  • the negative terminal of the power supply U DC is assumed to be grounded here, called ground. Because the left positive end of C1 is connected to the negative terminal of the power supply U DC through saturation, that is, the ground is negative, then the voltage at the right negative end of C1 is about -U.
  • DC in this excitation process, if the terminal voltage of C1 is insufficient due to insufficient capacity, that is, the voltage at the right negative end of C1 tends to rise, and its absolute value is smaller than U DC , then in the process of excitation, Q1 When the saturation conduction is excited to the first primary winding N P1 , a positive voltage is induced at the same end, and a negative voltage is induced at the opposite end.
  • N P1 and N P2 are double wound and wound, N P2 is also induced at both ends: the same name end induces a positive voltage, the different name end induces a negative voltage, the size is equal to U DC , this voltage will directly charge C1, this is a positive
  • the process is such that the terminal voltage of C1 does not drop anyly due to insufficient capacity; as mentioned above: the power supply U DC charges C1 through the two windings of the transformer B. These two windings cancel out due to the mutual inductance, which does not work, and C1 is equivalent.
  • DC internal resistance through N P1 and N P2 In parallel with the power supply U DC , the power supply U DC directly supplies power to C1 through a very low DC internal resistance, and its terminal voltage remains stable;
  • the excitation currents of 41 and 42 are in parallel. Since the inductances of N P1 and N P2 are the same, the excitation voltages are the same, and they are equal to U DC , 41 and 42 are completely equal.
  • the secondary winding N S is pressed. than the same induced voltage, the induced voltage is: n dot end induced voltage, induced-phase terminal of a negative voltage equal to U DC magnitude multiplied by the turns ratio n, i.e., N S induced positive voltage on the negative, this voltage
  • n dot end induced voltage
  • induced-phase terminal of a negative voltage equal to U DC magnitude multiplied by the turns ratio n, i.e., N S induced positive voltage on the negative
  • the currents of 41 and 42 increase linearly upward; the current direction flows from the same name end to the different name end in the inductance;
  • the gate of Q1 changes from high level to low level, Q1 also turns from saturation conduction to off. Since the current in the inductor cannot be abrupt, even though Q1 is off at this time, the currents of 41 and 42 still flow from the same name end. At the opposite end, since the current loop of the primary side has been cut, the energy in the core flows from the same name to the opposite end on the secondary side. Referring to Figure 2-4, the secondary winding N S appears to flow from the same name end to the different name end.
  • the initial magnitude of the current (the sum of 41 and 42 at the instant of Q1 turn-off) / ⁇ ratio n, which causes D2 to conduct a forward conduction, and through the D2 of the forward conduction, Capacitor C2 is charged and Vout establishes voltage or continuously outputs energy. This process is also the process of demagnetization.
  • the output of the flyback switching power supply is named after the primary winding is disconnected from the power supply.
  • the output voltage depends on the loop control circuit and the flyback transformer (as shown in Figure 1, Figure 2, Series B).
  • the primary side has nothing to do with the turns ratio of the secondary side; in the energy transfer process, the transformer B is not a function of transforming the voltage, but is an isolated version of the Buck-Boost converter through the function of the core freewheeling; therefore, the transformer B is usually Called a flyback transformer;
  • the circuit for demagnetizing the leakage inductance of the present invention is composed of D1 and a second primary winding N P2 , and the working principle is:
  • N P1 of the first primary winding and a second primary winding of bifilar N P2 leakage inductance between the two windings is zero, after Q1 is turned off and the moment, the leakage inductance energy is not transferred to the secondary edge of electrical energy, a second primary winding leakage inductance N P2 in which the direction of current in the same direction when energized, to flow from the dotted end dot end, i.e., in FIG. 2-4, by the upward flow, the opening of D1, and This electrical energy is absorbed by the DC power source U DC to form a leakage inductance demagnetizing current as indicated by 44;
  • the leakage energy of the first primary winding N P1 is coupled to the second primary winding N P2 without leakage inductance, and demagnetization is realized by D1, and the leakage inductance demagnetization current shown by 44 is also formed;
  • the output voltage Vout is divided by the turns ratio n, which is the "reflected voltage" formed on the primary side when the secondary winding N S is turned on at D2.
  • n the "reflected voltage" formed on the primary side when the secondary winding N S is turned on at D2.
  • the reflected voltage cannot be greater than the value of the DC power source U DC .
  • This circuit works well. Since the currents of 41 and 42 are the same, the wire diameters of the first primary winding and the second primary winding are the same, so that the winding is convenient, the wire diameters described herein are the same, and they are all of the same size Litz wire, the color can be Different, that is, multi-strand stranding, for the convenience of identification, the same specification wire including the Litz wire can have different colors.
  • the Litz wire can solve this problem.
  • two different colors of enameled wire are used to make the Litz wire first, and the first primary winding and the second primary winding are separated by color, or the wire diameter and the number of strands of the two windings are different. , both achieve the purpose of the invention.
  • the invention has many differences, mainly: the "third winding" of the conventional three-winding absorption flyback converter does not participate in the excitation, and only participates in demagnetization; In the invention, there is no third winding, and both primary windings participate in the excitation, and in the demagnetization, the second primary winding N P2 participates in the demagnetization of the leakage inductance, thereby achieving the lossless absorption of the leakage energy.
  • the demagnetization winding is the second.
  • primary winding N P2 it is also involved in the excitation to improve the current density of the primary winding, increases the power density converters.
  • the source of the DC power source U DC can be obtained by rectifying the AC power and filtering it by electrolytic capacitor filtering or valley filling circuit.
  • the present invention has the following beneficial effects: the leakage inductance between the primary and secondary windings is allowed to be large, the primary side is still wound by two wires, and the conversion efficiency is high; and the current density of the primary winding is improved. , to improve the power density of the converter; and suitable for lower operating voltage applications.
  • a flyback switching power supply includes a transformer B, an N-channel FET Q1, and a second capacitor C2.
  • the pole tube D1, the second diode D2, and the transformer B include a first primary winding N P1 , a second primary winding N P2 and a secondary winding N S , and a secondary winding N S different name end and a second diode D2 anode connection, the cathode of the second diode D2 is connected with one end of the second capacitor C2, and forms an output positive, which is the + end of Vout in the figure, and the opposite end of the secondary winding N S is connected with the other end of the second capacitor C2, and is formed.
  • the output is negative, which is the end of Vout in the figure; the positive terminal of the input DC power supply U DC is simultaneously connected to the drain of the N-channel FET Q1 and the second-side winding N P2 , and the N-channel FET Q1
  • the source is connected to the first end of the first primary winding N P1 ; the second primary winding N P2 is connected to the cathode of the first diode D1 at the same end, and the first primary winding N P1 is different from the first and second poles the anode of diode D1 is connected to the connection point while connected to the negative terminal of the DC power source input U DC; a gate connected to a control signal N-channel MOSFET Q1
  • a first primary winding N P1 and the second primary winding N P2 is bifilar, further comprising a first capacitor C1, a first capacitor C1 is connected to one end of the primary winding with a first terminal of the same name N P1, The other end of the first capacitor C1 is connected to the
  • the second embodiment is a modification of the first embodiment: on the basis of FIG. 2 of the first embodiment, the series devices of the two excitation circuits are interchanged, that is, N P1 and Q1 are interchanged, and at the same time D1 and N P2 exchange position, C1 is still connected between the connection points of two series devices, and the circuit of Fig. 3 of the second embodiment is obtained. Since the source voltage of Q1 is fluctuating, this circuit is floating. The driver should be costly and should not be used.
  • the terminal voltage of C1 is equal to the voltage of U DC , right and left negative;
  • the first way is: the positive end of the power supply U DC enters through the drain of Q1, the source of Q1 is out, and then enters through the same name of the first primary winding N P1 , and the different name of N P1 is output, returning to the power supply U DC Negative end
  • the second way is: the right positive end of the capacitor C1 passes through the same name of the second primary winding N P2 , the different name of N P2 is output, the drain of Q1 enters, the source of Q1 is out, and the left negative end of capacitor C1 is returned. ;
  • the negative terminal of the power supply U DC is assumed to be grounded here, called ground. Since the left negative end of C1 is connected to the positive terminal of the power supply U DC through the saturated conduction Q1, then the voltage at the right positive end of C1 is about 2U DC to ground.
  • the terminal voltage of C1 is insufficient due to insufficient capacity, that is, the voltage at the right positive end of C1 decreases, and the absolute value of C1 is less than U DC , then in the process of excitation, Q1 saturates to conduct the first When the primary winding N P1 is excited, a positive voltage is induced at the same name, and a negative voltage is induced at the opposite end.
  • the magnitude is equal to the voltage applied across N P1 , equal to U DC .
  • N P1 and N P2 are double wound and Around, N P2 ends are also induced: the same name end induces a positive voltage, the different name end induces a negative voltage, the size is U DC , this voltage will directly charge C1, this is a positive process, making the end of C1 The voltage will not drop any due to insufficient capacity; as mentioned above: the power supply U DC charges C1 through the two windings of the transformer B. These two windings cancel out due to mutual inductance and do not work.
  • C1 is equivalent to passing N P1 and N.
  • the DC internal resistance of P2 is connected in parallel with the power supply U DC , and the power supply U DC The electric energy is directly supplied to C1 through a very low DC internal resistance, and the terminal voltage thereof is maintained stable;
  • the first and second excitation currents are in parallel relationship. Since the inductances of N P1 and N P2 are the same and the excitation voltages are the same, they are equal to U DC , and the two paths are completely equal.
  • the secondary winding N S The induced voltage is also generated according to the ⁇ ratio, the positive voltage is induced by the same name end, and the negative voltage is induced by the different name.
  • the size is equal to U DC multiplied by the ⁇ ratio n, that is, N S induces a positive and negative voltage, this voltage and C2
  • the terminal voltage is connected in series, and is applied to both ends of D2, and D2 is reverse biased and not turned on. At this time, the secondary side is equivalent to no load, and no output;
  • the first and second excitation currents increase linearly upward; the current direction flows from the same name end to the different name end in the inductance;
  • the leakage energy of the first primary winding N P1 is coupled to the second primary winding N P2 without leakage inductance, and demagnetization is realized by D1, and a leakage inductance demagnetization current loop is also formed;
  • the second embodiment is a modification of the first embodiment, and the working principle is equivalent, and the object of the invention is also achieved.
  • an N-channel FET it can also be realized by a P-channel field effect transistor.
  • the P-channel FET has a low cost at a low operating voltage, and at this time, the basis of the first embodiment described above.
  • the polarity of the power supply, the diode, and the end of the same name are reversed, and the output rectification portion is not reversed, so the third embodiment is obtained, as described below.
  • a flyback switching power supply includes a transformer B, a P-channel FET Q1, a second capacitor C2, a first diode D1, and a second diode D2.
  • the transformer B includes a first primary winding N P1 , a second primary winding N P2 and a secondary winding N S , the secondary winding N S different end is connected to the second diode D2 anode, and the second diode D2 is cathode Connected to one end of the second capacitor C2, and form an output positive, which is the + end of Vout in the figure, the second end of the secondary winding N S is connected with the other end of the second capacitor C2, and forms an output negative, which is the end of Vout in the figure; Input the negative terminal of the DC power supply U DC - simultaneously connected to the first primary winding N P1 different name end, the anode of the first diode D1, the first primary winding N P1 the same name end and the P channel
  • the third embodiment reverses the polarity of the same name terminal of the power source U DC , the diode D1, the first primary winding N P1 and the second primary winding N P2 of the first embodiment.
  • N tube is replaced by P tube.
  • the positive terminal of the input power source U DC in FIG. 4 is ground, and belongs to the switching power supply of the negative power supply.
  • the P-channel FET itself is also driven by a negative level, which is just right.
  • a flyback switching power supply includes a transformer B, a P-channel FET Q1, a second capacitor C2, and a first diode D1.
  • the second diode D2 the transformer B includes a first primary winding N P1 , a second primary winding N P2 and a secondary winding N S , and the secondary winding N S different end is connected to the second diode D2 anode,
  • the cathode of the second diode D2 is connected to one end of the second capacitor C2, and forms an output positive, which is the + end of Vout in the figure, and the secondary winding N S is connected with the other end of the second capacitor C2, and forms an output negative.
  • the end of Vout is input; the negative terminal of the input DC power supply is simultaneously connected with the drain of the P-channel FET Q1 and the second-side winding N P2 , and the source and the first source of the P-channel FET Q1
  • the side winding N P1 is connected to the opposite end; the second primary winding N P2 is connected to the anode of the first diode D1, and the first primary winding N P1 is connected to the cathode of the first diode D1 at the same end.
  • the second primary winding is bifilar N P2, further comprising a first capacitor C1, one end of the first capacitor C1 is connected to the first primary winding N P1 dotted end, the other end of the first capacitor C1 and the second primary
  • the side windings N P2 are connected at different ends.
  • the fourth embodiment of FIG. 5 is a modification of the third embodiment: on the basis of FIG. 4 of the third embodiment, the series devices of the two excitation circuits are interchanged, that is, the positions of N P1 and Q1 are interchanged, and D1 and N P2 are interchanged, and C1 is still connected between the two series primary windings N P1 and N P2 , and the circuit of FIG. 5 of the fourth embodiment is obtained. Since the source voltage of Q1 is fluctuating, This circuit is floating drive and should be costly and should not be used.
  • the fourth embodiment is the pole of the same name of the power source U DC , the diode D1, the first primary winding N P1 and the second primary winding N P2 of the second embodiment of FIG. 3 .
  • the N tube is replaced by a P tube.
  • the positive terminal of the input power source U DC in FIG. 5 is ground, and also belongs to the switching power supply of the negative power supply.
  • the P-channel FET itself is also driven by a negative level, which is just right.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

Cette invention concerne une alimentation à découpage de type à accumulation (flyback), qui est basée sur un convertisseur commun flyback à absorption à trois enroulements. Un procédé de montage selon l'invention comprend les étapes consistant à : connecter une extrémité de polarité commune d'un premier enroulement primaire (NP1) dans un transformateur (B) à une alimentation électrique, et connecter une extrémité de polarité commune d'un second enroulement primaire (NP2) à la masse, en s'assurant que le premier enroulement primaire (NP1) et le second enroulement primaire (NP2) sont des enroulements à deux fils ; ajouter un condensateur (C1), une extrémité du condensateur(C1) étant connectée à une extrémité de polarité opposée du premier enroulement primaire (NP1) tandis qu'une autre extrémité est connectée à une extrémité de polarité opposée du second enroulement primaire (NP2). Ceci permet d'obtenir le fonctionnement suivant : lorsqu'un transistor à effet de champ (Q1) est saturé et mis sous tension, à la fois le premier enroulement primaire (NP1) et le second enroulement primaire (NP2) sont excités ; lorsque le transistor à effet de champ (Q1) est mis hors tension, un enroulement secondaire (nS) délivre de l'énergie, et l'énergie provenant de l'inductance de fuite est absorbée de manière non destructive par le second enroulement primaire (NP2) au moyen d'une diode (D1). L'invention est appropriée pour fonctionner à basse tension, et elle permet d'améliorer le taux d'utilisation et la densité de courant des enroulements primaires, et ainsi la densité de puissance est élevée, de sorte à permettre une grande inductance de fuite entre les côtés primaire et secondaire, tandis que l'efficacité de conversion est élevée.
PCT/CN2018/074968 2017-03-10 2018-02-01 Alimentation à découpage de type à accumulation Ceased WO2018161748A1 (fr)

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CN106655791B (zh) * 2017-03-10 2019-11-26 广州金升阳科技有限公司 一种反激式开关电源
CN107276414B (zh) * 2017-06-30 2020-02-14 广州金升阳科技有限公司 一种有源钳位反激式开关电源电路
CN107294388B (zh) * 2017-06-30 2020-02-14 广州金升阳科技有限公司 一种反激式开关电源
CN107786094B (zh) * 2017-06-30 2020-11-06 广州金升阳科技有限公司 一种正激开关电源
CN107196515A (zh) * 2017-06-30 2017-09-22 广州金升阳科技有限公司 一种有源钳位正激式开关电源电路
CN107196516B (zh) * 2017-06-30 2020-02-14 广州金升阳科技有限公司 一种反激式开关电源电路
CN107994762A (zh) * 2017-11-21 2018-05-04 浙江万胜智能科技股份有限公司 一种开关电源的无损吸收电路及开关电源
CN116345919B (zh) * 2023-05-29 2023-08-04 江苏大秦新能源科技有限公司 一种低交叉调整率和无损吸收的双路反激dcdc辅助电源

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