Multi-output flyback power supply

Abstract

This utility model discloses a multi-output flyback power supply. By setting at least one current compensation module, the first end of the current compensation module is connected to the secondary winding, and the second end of the current compensation module is connected to the power output terminal corresponding to the output circuit connected to the secondary winding. The current compensation module can output a corresponding compensation current to the power output terminal according to the current of the output circuit. When the load connected to the output circuit changes, the current compensation module can provide compensation current to the power output terminal connected to the output circuit, reducing the voltage change of the secondary winding connected to the output circuit, thereby reducing the mutual influence of voltage between different secondary windings, optimizing the cross-regulation rate, and improving output stability.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply circuit technology, and in particular to a multi-output flyback power supply. Background Technology

[0002] With the increasing popularity and diversification of electronic devices, the requirements for switching power supplies are also getting higher and higher.

[0003] In multi-output flyback power supplies, the issue of cross-regulation of multi-winding outputs is frequently encountered. The main control circuit of a multi-winding output power supply uses a closed-loop system to regulate the output voltage of one winding, while the other windings operate in an open-loop manner. When the load power of the main winding changes significantly, the output voltage of the other windings will also fluctuate considerably, resulting in poor output voltage stability.

[0004] Therefore, the cross-regulation rate of existing multi-output flyback power supplies needs to be optimized. Utility Model Content

[0005] This invention provides a multi-output flyback power supply to optimize the cross-regulation rate of the multi-output flyback power supply and improve the stability of the output voltage.

[0006] According to one aspect of this utility model, a multi-output flyback power supply is provided, comprising:

[0007] A transformer, comprising a primary winding and at least two secondary windings;

[0008] At least two output circuits, each output circuit including a first rectifier unit connected between the secondary winding and the power output terminal;

[0009] At least one current compensation module is provided, with its first end connected to the secondary winding and its second end connected to the power output terminal of the output circuit connected to the secondary winding, for outputting a corresponding compensation current to the power output terminal according to the current of the output circuit.

[0010] Optionally, the current compensation module includes a compensation winding, a second rectifier unit, and a current amplification unit;

[0011] The compensation winding is connected in series with the secondary winding. The first end of the second rectifier unit is connected to the compensation winding. The second end of the second rectifier unit is connected to the first end of the current amplification unit. The second end of the current amplification unit is connected to the power output terminal.

[0012] The control terminal of the current amplification unit is connected to the output circuit. When the current in the output circuit meets the conduction condition, it connects the first and second terminals of the current compensation module to output the corresponding compensation current to the power output terminal.

[0013] Optionally, the current amplification unit includes a switching amplification subunit and a current detection subunit. The current detection subunit is used to generate a corresponding detection voltage based on the current in the output circuit. The switching amplification subunit is used to turn on or off based on the detection voltage, and when it is on, it connects the first and second terminals of the current compensation module to output the corresponding compensation current to the power output terminal.

[0014] Optionally, the current sensing subunit is connected in series between the first rectifier unit and the power output terminal, the control terminal of the switching amplification subunit is connected to the first terminal of the current sensing subunit, the first terminal of the switching amplification subunit is connected to the second terminal of the second rectifier unit, the second terminal of the switching amplification subunit is connected to the second terminal of the current sensing subunit, and the second terminal of the switching amplification subunit is connected to the power output terminal.

[0015] Optionally, the switching amplification subunit includes a transistor, and the current sensing subunit includes a first resistor;

[0016] The base of the transistor serves as the control terminal of the switching amplifier subunit, the collector of the transistor serves as the first terminal of the switching amplifier subunit, and the emitter of the transistor serves as the second terminal of the switching amplifier subunit.

[0017] The first end of the first resistor serves as the first end of the current detection subunit, and the second end of the first resistor serves as the second end of the current detection subunit.

[0018] Optionally, the number of turns in the compensation winding is less than or equal to the number of turns in the corresponding connected secondary winding.

[0019] Optionally, the number of turns in the compensation winding is equal to 1.

[0020] Optionally, the compensation winding is connected in series with the same terminal of the secondary winding.

[0021] Optionally, the current compensation module also includes a dummy load unit and a filter unit. The dummy load unit is connected to the second terminal of the first rectifier unit, and the second terminal of the dummy load unit is connected to a reference voltage. The filter unit is connected in parallel with the dummy load unit.

[0022] Optionally, the output circuit may also include a storage unit connected to the power output terminal.

[0023] Optionally, the multi-output flyback power supply also includes an input circuit, which includes a power supply and switching unit connected in series with the primary winding.

[0024] The multi-output flyback power supply of this utility model embodiment includes at least one current compensation module. The first end of the current compensation module is connected to the secondary winding, and the second end of the current compensation module is connected to the power output terminal corresponding to the output circuit connected to the secondary winding. The current compensation module can output a corresponding compensation current to the power output terminal according to the current of the output circuit. When the load connected to the output circuit changes, the current compensation module can provide compensation current to the power output terminal connected to the output circuit, reducing the voltage change of the secondary winding connected to the output circuit, thereby reducing the mutual influence of voltage between different secondary windings, optimizing the cross-regulation rate, and improving output stability.

[0025] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a multi-output flyback power supply provided in an embodiment of this utility model;

[0028] Figure 2 This is a schematic diagram of another multi-output flyback power supply provided in this embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of another multi-output flyback power supply provided in this embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of another multi-output flyback power supply provided in an embodiment of the present invention. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0033] Figure 1 This is a schematic diagram of a multi-output flyback power supply provided in an embodiment of this utility model. (Refer to...) Figure 1 The multi-output flyback power supply includes: a transformer 100, which includes a primary winding N1 and at least two secondary windings N2; at least two output circuits 200, each including a first rectifier unit 210 connected between the secondary windings N2 and the power output terminal Uout; and at least one current compensation module 300, the first end of which is connected to the secondary windings N2, and the second end of which is connected to the power output terminal Uout of the output circuit 200 connected to the secondary windings N2, for outputting a corresponding compensation current to the power output terminal Uout according to the current of the output circuit 200.

[0034] Specifically, the transformer 100 includes a magnetic core and windings, with the windings including a primary winding N1 and a secondary winding N2. In this embodiment of the invention, the transformer 100 includes a primary winding N1 and at least two secondary windings N2 to achieve at least two outputs. Each secondary winding N2 is connected to an output circuit 200; optionally, each secondary winding N2 is connected to one output circuit 200. The output circuit 200 includes a first rectifier unit 210, which is connected in series between the secondary windings N2 and the power output terminal Uout. The first rectifier unit 210 may include rectifier diodes. Figure 1 The diagram schematically illustrates a multi-output flyback power supply comprising two output circuits 210, denoted as the first output circuit 201 and the second output circuit 202. The secondary winding of the first output circuit 201 is connected to the first secondary winding N21, and the secondary winding of the second output circuit 202 is connected to the second secondary winding N22. The first output circuit 201 is connected to the first power supply output terminal Uout1, and the second output circuit 202 is connected to the second power supply output terminal Uout2.

[0035] In related technologies, in multi-output flyback power supplies, one output circuit 200 is typically used as the main output, and the other output circuits 200 are used as auxiliary outputs. The main output operates in a closed-loop manner, while the auxiliary outputs operate in an open-loop manner. That is, the main output can be controlled by collecting the voltage at the power output terminal corresponding to the main output, while the auxiliary outputs have no feedback control. When the load power connected to the main output terminal Uout changes, it causes a change in the current in the output circuit 200, resulting in a change in line voltage drop, especially a large change in the voltage drop of the first rectifier unit 210. Since the voltage on the secondary winding is positively correlated with the sum of the voltage drop of the first rectifier unit 210 and the voltage at the power output terminal, and the output voltage at the power output terminal Uout is kept stable through closed-loop control, the voltage on the secondary winding corresponding to the main output will change with the change in the voltage drop of the first rectifier unit 210. Depending on the turns ratio between different secondary windings, the voltage on the secondary winding of the auxiliary output will also change, resulting in a large cross-regulation and poor output stability of the multi-output flyback power supply.

[0036] Unlike related technologies, in this embodiment of the invention, the multi-output flyback power supply includes at least one current compensation module 300. In some embodiments, the secondary winding N2 connected to the main output circuit 200 (i.e., the closed-loop output circuit 200) is connected to the current compensation module 300. In other embodiments, the secondary winding N2 connected to the auxiliary output circuit 200 (i.e., the open-loop output circuit 200) is connected to the current compensation module 300. In still other embodiments, the secondary windings N2 connected to the main output circuit 200 and the auxiliary output circuit 200 are respectively connected to the current compensation module 300, wherein the secondary windings connected to different output circuits 200 correspond to different current compensation modules 300. The current compensation module 300 is connected to the secondary winding N2, the output circuit 200 connected to the secondary winding N2, and the power output terminal Uout corresponding to the secondary winding N2. The current compensation module 300 can detect the current in the connected output circuit 200 and compensate the power output terminal Uout according to the current in the output circuit 200. Figure 1 The diagram illustrates the connection between the primary winding N21 of the first output circuit 201 and the current compensation module 300.

[0037] When the secondary winding N2 of the main output circuit 200 is connected to the current compensation module 300, and the load power connected to the main output circuit 200 changes, the current compensation module 300 outputs a compensation current to the power output terminal Uout, thereby reducing the current change of the main output circuit 200. Consequently, the line voltage drop change of the main output circuit 200 can be reduced, for example, the voltage drop change of the first rectifier unit 210 is reduced. As a result, the voltage change on the secondary winding connected to the main output circuit 200 is reduced, and the voltage impact on other secondary windings connected to the auxiliary output circuit 200 is smaller, thereby reducing the cross-regulation rate and improving output stability.

[0038] When the secondary winding N2 of the output circuit 200, which serves as the auxiliary output, is connected to the current compensation module 300, if the load power connected to the output circuit 200 changes, or if the load power connected to the output circuit 200, which serves as the main output, causes the load current of the output circuit 200 to be too large, the current compensation module 300 can output compensation current to the power output terminal Uout of the output circuit 200, thereby reducing the current change in the output circuit 200, thus reducing the voltage change on the first rectifier unit 210 in the output circuit 200, and further reducing the voltage change on the secondary winding connected to the output circuit 200, thereby reducing the cross-regulation rate and improving output stability.

[0039] The multi-output flyback power supply in this embodiment includes at least one current compensation module. The first end of the current compensation module is connected to the secondary winding, and the second end is connected to the power output terminal corresponding to the output circuit connected to the secondary winding. The current compensation module can output a corresponding compensation current to the power output terminal according to the current of the output circuit. When the load connected to the output circuit changes, the current compensation module can provide compensation current to the power output terminal connected to the output circuit, reducing the voltage change of the secondary winding connected to the output circuit. This reduces the mutual influence of voltages between different secondary windings, optimizes the cross-regulation rate, and improves output stability.

[0040] Figure 2 This is a schematic diagram of another multi-output flyback power supply provided in an embodiment of this utility model, for reference. Figure 2Optionally, the current compensation module 300 includes a compensation winding 310, a second rectifier unit 320, and a current amplification unit 330. The compensation winding 310 is connected in series with the secondary winding N2. The first end of the second rectifier unit 320 is connected to the compensation winding 310, and the second end of the second rectifier unit 320 is connected to the first end of the current amplification unit 330. The second end of the current amplification unit 330 is connected to the power output terminal Uout. The control terminal of the current amplification unit 330 is connected to the output circuit 200 and is used to conduct the current between the first and second ends of the current compensation module 300 when the current in the output circuit 200 meets the conduction condition, and output the corresponding compensation current to the power output terminal Uout.

[0041] Optionally, the compensation winding 310 is connected in series with the same terminal of the secondary winding N2, and the compensation winding 310 has at least one turn. By including the compensation winding 310 in the current compensation module 300, an additional winding output can be provided to compensate the load connected to the power output terminal Uout. The current compensation module 300 also includes a second rectifier unit 320 and a current amplification unit 330, which are connected in series between the compensation winding 310 and the power output terminal Uout. The second rectifier unit 320 may include a rectifier diode. The control terminal of the current amplification unit 330 is connected to the output circuit 200. When the current in the output circuit 200 meets the conduction condition of the current amplification unit 330, the current amplification unit 330 is turned on, amplifying the current at the control terminal of the current amplification unit 330 and outputting the amplified current to the power output terminal Uout, which in turn is output to the load. Thus, when the load power increases, a compensation current is provided to the load. Due to the current amplification effect of the current amplification unit 330, the compensation current is greater than the current in the output circuit 200. Therefore, when the load power increases, the current in the output circuit 200 remains almost unchanged, and the compensation current of the current amplification unit 330 can meet the load power requirements. This makes the voltage drop change on the first rectifier unit 210 in the output circuit 200 smaller. Correspondingly, the voltage change on the secondary winding connected to the output circuit 200 is small, and the impact on the voltage of other secondary windings is also reduced, optimizing the cross-regulation rate and improving output stability.

[0042] Figure 2 In the circuit, the first output circuit 201 is connected to the power output terminal Uout, that is, the first power output terminal Uout1 is connected to the first load R3; the second output circuit 202 is connected to the power output terminal Uout, that is, the second power output terminal Uout2 is connected to the second load R4. Figure 2The example shows that in the first output circuit 201, the first rectifier unit 210 includes a first diode D1; in the second output circuit 202, the first rectifier unit 210 includes a second diode D2; and in the current compensation module 300, the second rectifier unit 320 includes a third diode D3.

[0043] In some embodiments, the conduction condition of the current amplification unit 330 includes the current in the output circuit 200 being greater than or equal to a set current threshold.

[0044] Optionally, the number of turns of the compensation winding 310 is less than or equal to the number of turns of the corresponding connected secondary winding N2.

[0045] Specifically, the more turns the compensation winding 310 has, the greater the increase in losses in the multi-output flyback power supply. By setting the number of turns of the compensation sleeve to be less than or equal to the number of turns of the corresponding connected secondary winding N2, the losses of the multi-output flyback power supply can be reduced, optimizing the cross-regulation rate while also considering efficiency.

[0046] In some embodiments, the number of turns in the compensation winding 310 is equal to 1. This further reduces losses in the multi-output flyback power supply.

[0047] Continue to refer to Figure 2 Optionally, the current amplification unit 330 includes a switching amplification subunit 331 and a current detection subunit 332. Optionally, the current detection subunit 332 is connected in series between the first rectifier unit 210 and the power output terminal Uout. The control terminal of the switching amplification subunit 331 is connected to the first terminal of the current detection subunit 332, the first terminal of the switching amplification subunit 331 is connected to the second terminal of the second rectifier unit 320, the second terminal of the switching amplification subunit 331 is connected to the second terminal of the current detection subunit 332, and the second terminal of the switching amplification subunit 331 is connected to the power output terminal Uout. The current detection subunit 332 is used to generate a corresponding detection voltage based on the current in the output circuit 200, for example, generating a corresponding detection voltage between the control terminal and the second terminal of the switching amplification subunit 331. The switching amplification subunit 331 is used to turn on or off according to the detection voltage, and when on, it turns on the current compensation module 300 between the first and second terminals, outputting a corresponding compensation current to the power output terminal Uout.

[0048] Specifically, the current detection subunit 332 can detect the current in the output circuit 200 connected to it, and generate a corresponding detection voltage between the control terminal and the second terminal of the switching amplifier subunit 331 according to the current in the output circuit 200. When the detection voltage meets the conduction condition for the switching amplifier subunit 331 to conduct, the switching amplifier subunit 331 conducts and outputs a corresponding compensation current to the power output terminal Uout.

[0049] Continue to refer to Figure 2 In some embodiments, the switching amplification subunit 331 includes a transistor Q1, and the current detection subunit 332 includes a first resistor R1; the base of the transistor Q1 serves as the control terminal of the switching amplification subunit 331, the collector of the transistor Q1 serves as the first terminal of the switching amplification subunit 331, and the emitter of the transistor Q1 serves as the second terminal of the switching amplification subunit 331; the first terminal of the first resistor R1 serves as the first terminal of the current detection subunit 332, and the second terminal of the first resistor R1 serves as the second terminal of the current detection subunit 332.

[0050] Specifically, when the first resistor R1 carries a current I R1 At that time, the voltage U across the first resistor R1 R1 =I R1 *R1, when the current increases, U R1 When the voltage increases to the amplification region of transistor Q1, current flows from Q1 to the load. As the load power connected to the power output terminal Uout continues to increase, due to the current amplification effect of transistor Q1 (typically 50 to 200 times), even when the current increase in the output circuit is small, the compensation current output by transistor Q1 will change significantly. Therefore, it can be approximated by the increase in load power at the power output terminal Uout, causing the voltage U across the first resistor R1 to increase. R1 After reaching the base amplification region of transistor Q1, the output current in output circuit 200 remains almost unchanged. The increased current required by the increased load power is basically output by transistor Q1, that is, by the second rectifier unit 320. In this way, the current of the first rectifier unit 210 remains unchanged, the voltage drop of the first rectifier unit 210 remains unchanged, and the positive voltage output by the secondary winding remains unchanged.

[0051] According to U N21 =U out1 +U R1 +U D1 U N21 U represents the voltage across the primary winding N21. out1 This represents the voltage at the first power supply output terminal Uout1, U D1 This represents the voltage drop across the first diode D1. When the compensated output is the main closed-loop output of the flyback power supply, U... out1 Constant, the load power satisfies the condition that U R1 =I R1 *After R1 reaches the transistor amplification region, U N21 The relationship remains essentially unchanged. This ensures that the outputs of other windings are also stably clamped to this voltage turns ratio, improving the cross-regulation.

[0052] When the compensated output is applied to the open-loop output of a flyback power supply. Similarly, when the load power satisfies U R1 =IR1 *R1 reaches the voltage of the transistor amplification region. When the output load increases, the line voltage drop changes only slightly. The increased load current is provided by the compensation winding 310, and the output voltage will not be affected by the increase in its own load.

[0053] Figure 3 This is a schematic diagram of another multi-output flyback power supply provided in an embodiment of this utility model, for reference. Figure 3 Optionally, in the multi-output flyback power supply, the current compensation module 300 also includes a dummy load unit 340 and a filter unit 350. The dummy load unit 340 is connected to the second terminal of the first rectifier unit 210, and the second terminal of the dummy load unit 340 is connected to a reference voltage. The filter unit 350 is connected in parallel with the dummy load unit 340.

[0054] By setting up a dummy load unit 340, the fluctuation of the output voltage of the first rectifier unit 210 can be reduced, thus improving stability. The dummy load unit 340 may include a second resistor R2, and the filter unit 350 may include a first capacitor C1. Optionally, the reference voltage can be ground, and the second terminal of the dummy load unit 340 can be grounded (GND).

[0055] Continue to refer to Figures 2-3 Optionally, in this multi-output flyback power supply, the output circuit 200 further includes a storage unit 220, which is connected to the power output terminal Uout. By storing energy in the storage unit 220, power can be supplied to the load at the power output terminal Uout. Optionally, the storage unit 220 includes a second capacitor. Figure 2 and Figure 3 The diagram schematically shows that in the first output circuit 201, the second capacitor included in the storage unit 200 is the second capacitor A C21; in the second output circuit 202, the second capacitor included in the storage unit 200 is the second capacitor B C22.

[0056] Figure 4 This is a schematic diagram of another multi-output flyback power supply provided in an embodiment of this utility model, for reference. Figure 4 In some embodiments, the multi-output flyback power supply also includes an input circuit 400, which includes a power supply 410 and a switching unit 420 connected in series with the primary winding N1.

[0057] The control terminal of the switching unit 420 can be connected to a controller. The controller controls the switching state of the switching unit 420 by providing a pulse width modulation signal to the control terminal of the switching unit 420. When the switching unit 420 is turned on, the DC input voltage of the power supply 410 is applied to the primary winding N1 of the transformer 100. At this time, the primary winding N1 is equivalent to an inductor, and energy is stored in the inductor in the form of magnetic energy. The primary winding N1 is positive at the top and negative at the bottom, the secondary winding N2 is negative at the top and positive at the bottom, and the compensation winding 310 is negative at the top and positive at the bottom. The first rectifier unit 210 in the output circuit 200 and the second rectifier unit 320 in the current compensation module 300 are turned off, and the storage unit 220 supplies power to the load. When the switching unit 420 is turned off, magnetic energy is transferred from the primary winding N1 to the secondary winding N2 and the compensation winding 310. The primary winding N1 is negative at the top and positive at the bottom, the secondary winding N2 is positive at the top and negative at the bottom, and the compensation winding 310 is positive at the top and negative at the bottom. The first rectifier unit 210 in the output circuit 200 is turned on, and the second rectifier unit 320 in the current compensation module charges the storage unit 220 to supply power to the load.

[0058] The following provides a specific illustrative description of the multi-output flyback power supply according to an embodiment of the present invention.

[0059] Assuming the first output circuit 201 outputs a closed loop and the second output circuit 202 outputs an open loop, because U N21 =U out1 +U R1 +U D1 The system can be designed so that the current Iso of the commonly used load or minimum load is at the compensation start point. Then, when the load power increases, causing the current in the first output circuit 201 to exceed the minimum load current Iso, due to the current compensation effect of the current compensation module 300, U... R1 +U D1 If it remains essentially unchanged, then U N21 Basically unchanged. Assuming the turns ratio of the second-stage winding N22 to the first-stage winding N21 is N22 / N21 = k, then the voltage U of the second-stage winding N22... N22 =U N21 *kU D2 , among which, U D2 This indicates the voltage across the second diode D2; therefore, the voltage across the open winding (i.e., the second secondary winding N22) is basically unaffected by the load changes of its closed winding.

[0060] The increase in loss is approximately: U N3 *I D3 ;U N3 To compensate for the voltage of winding 310 (usually the voltage of one turn), I D3 The average current output for the third diode D3 is...

[0061] Assume that: the first power supply output terminal Uout1 maintains a stable closed-loop output of 12V; the first stage winding N21 has 6 turns, the second stage winding N22 has 11 turns, and the compensation winding 310 has 1 turn. Assume the following device parameters: the turn-on voltage U of transistor Q1 entering the amplification region... BE =0.5V, based on the design of the commonly used load or minimum load as the compensation starting point Iso=1A, etc., R1=U BE / Iso=0.5 / 1=0.5Ω. The average voltage U of the first diode D1. D1 =0.6V; then the average voltage of the primary winding N21 at this time is U N21 =U out1 +U R1 +U D1 =12 + 0.5 + 0.6 = 13.1V, then the voltage per turn U N21 =13.1 / 6=2.18V.

[0062] The combined output voltage of the primary winding N21 and the compensating winding 310 is U = 15.28V. When the load increases, the current is primarily supplied by the output of the third diode D3. This increases the loss by 2.18V multiplied by the average output current of the third diode D3. However, with optimized cross-regulation, the voltages of other multi-channel open-circuit windings remain stable, such as the secondary winding N22, which maintains a voltage of U. N22 =13.1*(11 / 6)=24V.

[0063] Assume that the first output circuit 201 is an open-loop output and the second output circuit 202 is a closed-loop output. Because U N21 =U out1 +U R1 +U D1 ; then U out1 =U N21 -U R1 -U D1 When the load power of the first output circuit 201 increases, U R1 =U BE Afterwards, it remains basically unchanged and is not affected by the increase in its own load. The voltage at the first power supply output terminal Uout1 is basically only affected by U N21 Influence.

[0064] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0065] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A multi-output flyback power supply, characterized by, include: A transformer, the transformer comprising a primary winding and at least two secondary windings; At least two output circuits, each output circuit including a first rectifier unit connected between the secondary winding and the power output terminal; At least one current compensation module, wherein a first end of the current compensation module is connected to the secondary winding, and a second end of the current compensation module is connected to the power output terminal corresponding to the output circuit connected to the secondary winding, for outputting a corresponding compensation current to the power output terminal according to the current of the output circuit.

2. The multi-output flyback power supply of claim 1, wherein, The current compensation module includes a compensation winding, a second rectifier unit, and a current amplification unit. The compensation winding is connected in series with the secondary winding, the first end of the second rectifier unit is connected to the compensation winding, the second end of the second rectifier unit is connected to the first end of the current amplification unit, and the second end of the current amplification unit is connected to the power output terminal. The control terminal of the current amplification unit is connected to the output circuit, and is used to conduct between the first terminal and the second terminal of the current compensation module when the current in the output circuit meets the conduction condition, so as to output the corresponding compensation current to the power output terminal.

3. The multi-output flyback power supply of claim 2, wherein, The current amplification unit includes a switching amplification subunit and a current detection subunit. The current detection subunit is used to generate a corresponding detection voltage based on the current in the output circuit. The switching amplification subunit is used to turn on or off based on the detection voltage, and when it is turned on, it connects the first terminal and the second terminal of the current compensation module to output a corresponding compensation current to the power output terminal.

4. The multi-output flyback power supply of claim 3, wherein, The current sensing subunit is connected in series between the first rectifier unit and the power output terminal. The control terminal of the switching amplification subunit is connected to the first terminal of the current sensing subunit. The first terminal of the switching amplification subunit is connected to the second terminal of the second rectifier unit. The second terminal of the switching amplification subunit is connected to the second terminal of the current sensing subunit and the second terminal of the switching amplification subunit is connected to the power output terminal.

5. The multi-output flyback power supply of claim 4, wherein, The switching amplification subunit includes a transistor, and the current detection subunit includes a first resistor; The base of the transistor serves as the control terminal of the switching amplifier subunit, the collector of the transistor serves as the first terminal of the switching amplifier subunit, and the emitter of the transistor serves as the second terminal of the switching amplifier subunit. The first end of the first resistor serves as the first end of the current detection subunit, and the second end of the first resistor serves as the second end of the current detection subunit.

6. The multi-output flyback power supply of claim 2, wherein, The number of turns of the compensation winding is less than or equal to the number of turns of the corresponding connected secondary winding.

7. The multi-output flyback power supply of claim 2, wherein, The number of turns in the compensation winding is equal to 1.

8. The multi-output flyback power supply of claim 2, wherein, The compensation winding is connected in series at the same end of the secondary winding.

9. The multi-output flyback power supply of claim 2, wherein, The current compensation module further includes a dummy load unit and a filter unit. The dummy load unit is connected to the second terminal of the first rectifier unit, and the second terminal of the dummy load unit is connected to a reference voltage. The filter unit is connected in parallel with the dummy load unit.

10. The multi-output flyback power supply according to any one of claims 1-9, characterized in that, The output circuit also includes a storage unit, which is connected to the power output terminal.

11. The multi-output flyback power supply according to any one of claims 1-9, characterized in that, The multi-output flyback power supply also includes an input circuit, which includes a power supply and a switching unit connected in series with the primary winding.

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