Multi-output switching power supply and control method thereof

Abstract

The invention provides a multi-output switching power supply and a control method thereof, and the multi-output switching power supply comprises a power conversion module which carries out the power conversion of an input signal of the multi-output switching power supply according to a driving signal, and obtains a first output signal; the power distribution module responds to the multi-path distribution signal to convert the first output signal into a plurality of output signals; the control circuit is used for generating a driving signal according to feedback of an output signal of a first power distribution unit in the multi-path power distribution unit and generating a multi-path distribution signal according to feedback of output signals of other power distribution units in the multi-path power distribution unit, each path of power distribution unit comprises a first transistor and a second transistor which are connected back to back, and the first transistor and the second transistor are connected back to back. And each path of distribution signal is used for controlling the switching state of the first transistor and the second transistor of the corresponding path. The working efficiency of the multi-output switching power supply can be improved, and the heating condition and the system cost during working are reduced.

Description

Technical Field

[0001] The present application relates to the technical field of chargers, and in particular to a multi-output switching power supply and a control method thereof. Background Art

[0002] A charger is a device that converts alternating current into low-voltage direct current. With the development of fast charging technology and the widespread application of mobile phone peripherals, there are more and more dual-port or multi-port chargers on the market, and there is an increasing demand for one of the output ports on a multi-port charger to have a fast charging function.

[0003] Currently, most of the dual-port or multi-port chargers with fast charging function on the market have two independent circuits or a secondary DC-DC converter to meet the different voltages required for fast charging and normal charging. This will cause the charger to become larger in size. At the same time, adding a DC-DC circuit will increase the number of components, leading to increased costs. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a multi-output switching power supply and a control method thereof, aiming to improve the output efficiency of the multi-output switching power supply and reduce heat generation and system cost during operation.

[0005] According to a first aspect of the present application, a multi-output switching power supply is provided, comprising:

[0006] A power conversion module, performing power conversion on an input signal of the multi-output switching power supply according to a driving signal to obtain a first output signal;

[0007] A multi-way power distribution unit, respectively coupled between the output end of the power conversion module and the multi-way output end of the multi-output switching power supply, responding to a multi-way distribution signal to convert the first output signal into a plurality of output signals, the plurality of output signals are respectively output from the multi-way output end;

[0008] The control circuit generates the driving signal according to the output signal feedback of the first power distribution unit in the multi-way power distribution unit, and generates multiple distribution signals according to the output signal feedback of other power distribution units in the multi-way power distribution unit,

[0009] Each of the power distribution units comprises: a first transistor and a second transistor connected back to back, and each distribution signal is used to control the switching state of the first transistor and the second transistor of the corresponding path.

[0010] Optionally, the first transistor and the second transistor are low voltage transistors.

[0011] Optionally, the first transistor and the second transistor are switch transistors; the cathode of the body diode of the first transistor is coupled to the output end of the power conversion module, and the cathode of the body diode of the second transistor is coupled to a corresponding output end of the multiple output ends;

[0012] The distribution signal of each path includes a first distribution signal and a second distribution signal. The control end of the first transistor receives the first distribution signal of the corresponding path, and the control end of the second transistor receives the second distribution signal of the corresponding path.

[0013] Optionally, the first transistor is a switch tube, and the second transistor is a diode; the cathode of the body diode of the first transistor is coupled to the output end of the power conversion module, the anode of the diode is coupled to the anode of the body diode of the first transistor, and the cathode of the diode is coupled to the corresponding output end of the multiple output ends; the control end of the first transistor receives the distribution signal of the corresponding path.

[0014] Optionally, the multiple distribution signals are configured to: control the first transistor in each power distribution unit to be turned on alternately; control the second transistor in each power distribution unit to be turned on or continuously turned off during the period when the first transistor in the corresponding power distribution unit is turned on.

[0015] Optionally, the multiple distribution signals are further configured to control the first transistor in each power distribution unit to be turned on alternately.

[0016] Optionally, the magnitude of the output signal of each power distribution unit is positively correlated with the conduction time length of the first transistor in the power distribution unit.

[0017] Optionally, there is a dead time between the first transistor in each power distribution unit and the second transistor in the next power distribution unit that is turned on.

[0018] Optionally, there is an overlapping conduction time between two first transistors in two adjacent turned-on power distribution units.

[0019] Optionally, the multi-channel power distribution unit includes: the first power distribution unit and the second power distribution unit; the control circuit includes: a distribution control module and a drive control module;

[0020] The distribution control module generates a first error adjustment signal according to the output signal feedback of the first power distribution unit and transmits the first error adjustment signal to the drive control module. The drive control module generates the drive signal according to the first error adjustment signal to control the switch state of the main power tube in the power conversion module.

[0021] The distribution control module generates a second error adjustment signal according to the output signal feedback of the second power distribution unit, generates the first on-time indication signal according to the second error adjustment signal, and performs a logic operation on the first on-time indication signal, the on-indication signal of the main power tube, and the off-indication signal of the main power tube to generate a plurality of distribution signals to control the switch state of each transistor in the multi-channel power distribution unit.

[0022] The first on-time indication signal is used to indicate that the expected on-time of the first transistor in the second power distribution unit after the main power tube is turned off is the first on-time, and the size of the first on-time is controlled according to the second error adjustment signal.

[0023] Optionally, the distribution control module is configured to: control the first transistor in the second power distribution unit to turn on during the period when the main power tube is turned on;

[0024] After the first transistor in the second power distribution unit is turned on for the overlapping conduction time, controlling the first transistor in the first power distribution unit to be turned off;

[0025] After the main power tube is turned off for a first time, controlling the first transistor in the first power distribution unit to turn on;

[0026] After the main power tube is turned off for a second time, the first transistor in the second power distribution unit is controlled to be turned off, and the second time is greater than the first time.

[0027] Optionally, when the first on-time is greater than a preset first time threshold and less than a preset second time threshold, the allocation control module is further configured to:

[0028] After the main power tube is turned off and before the first transistor in the second power distribution unit is turned off, controlling the second transistor in the second power distribution unit to be turned on for a third time;

[0029] After the first transistor in the second power distribution unit is turned off and before the first transistor in the first power distribution unit is turned off, the second transistor in the first power distribution unit is controlled to be turned on for a fourth time, wherein the first time threshold is equal to the sum of a preset minimum on-time threshold and a dead time, and the second time threshold is a preset maximum on-time threshold.

[0030] Further, the first time is equal to the first on-time minus the overlapping on-time; the second time is equal to the first on-time; the third time is equal to the first on-time minus the overlapping on-time minus the dead time;

[0031] The fourth time is equal to the time length between the turn-off moment of the first transistor in the second power distribution unit and the first moment minus the dead time, and the first moment represents the moment when the drain voltage of the second transistor in the first power distribution unit is greater than the drain voltage of the first transistor in the first power distribution unit.

[0032] Optionally, when the first on-time is greater than or equal to a preset second time threshold, the distribution control module is further configured to: after the main power tube is turned off and before the first transistor in the second power distribution unit is turned off, control the second transistor in the second power distribution unit to be turned on for a third time; and control the second transistor in the first power distribution unit to be continuously turned off, wherein the second time threshold is a preset maximum on-time threshold.

[0033] Further, the first time is equal to the sum of the third time and the dead time;

[0034] The second time is equal to the sum of the third time, the dead time and the overlapping conduction time; the third time is equal to the time length between the shutdown moment of the main power tube and the second moment, and the second moment indicates the moment when the drain voltage of the second transistor in the second power distribution unit is greater than the drain voltage of the first transistor in the second power distribution unit.

[0035] Optionally, when the first on-time is less than or equal to a preset first time threshold, the allocation control module is further configured to: control the second transistor in the second power distribution unit to be continuously turned off; after the first transistor in the second power distribution unit is turned off and before the first transistor in the first power distribution unit is turned off, control the second transistor in the first power distribution unit to be turned on for a fourth time, wherein the first time threshold is equal to the sum of the preset minimum on-time threshold and the dead time.

[0036] Further, the first time is equal to zero; the second time is equal to the overlapping conduction time; the fourth time is equal to the time length between the turn-off moment of the first transistor in the second power distribution unit and the first moment minus the dead time, and the first moment represents the moment when the drain voltage of the second transistor in the first power distribution unit is greater than the drain voltage of the first transistor in the first power distribution unit.

[0037] Optionally, the multi-channel power distribution unit includes: the first power distribution unit, the second power distribution unit and the third power distribution unit; the control circuit includes: a distribution control module and a drive control module; the distribution control module generates a first error adjustment signal according to the output signal feedback of the first power distribution unit and transmits it to the drive control module, and the drive control module generates the drive signal according to the first error adjustment signal to control the switch state of the main power tube in the power conversion module;

[0038] The distribution control module generates a second error adjustment signal based on the output signal feedback of the second power distribution unit, generates a third error adjustment signal based on the output signal feedback of the third power distribution unit, and generates three distribution signals based on the second error adjustment signal and the third error adjustment signal to respectively control the switching state of each transistor in the first power distribution unit, the second power distribution unit and the third power distribution unit.

[0039] Optionally, the multi-output switching power supply further includes: a voltage overshoot protection unit, coupled to the output end of the power conversion module, and configured to control the first output signal within a certain range during the startup of the multi-output switching power supply.

[0040] Optionally, the multi-output switching power supply further includes: a switch connection path is provided between the output end of each power distribution unit and the corresponding load connection end, which is turned on when a load device is connected to the corresponding coupled output end, thereby turning on the switch connection path.

[0041] Optionally, the power conversion module includes: a main power tube, a rectifier tube and a transformer;

[0042] The main power tube is connected to the primary winding of the transformer, the rectifier tube is connected to the secondary winding of the transformer, and the voltage on the secondary winding of the transformer is rectified by the rectifier tube to obtain the first output signal; the main power tube and the rectifier tube are high-voltage transistors.

[0043] Optionally, the rectifier tube is connected between the secondary winding and a ground terminal.

[0044] According to a second aspect of the present application, a control method for a multi-output switching power supply is provided, wherein the multi-output switching power supply includes a multi-channel power distribution unit, and the control method includes:

[0045] Generate a driving signal according to the output signal feedback of the first power distribution unit in the multi-way power distribution unit, and generate a multi-way distribution signal according to the output signal feedback of other power distribution units in the multi-way power distribution unit;

[0046] Performing power conversion on an input signal of the multi-output switching power supply according to the driving signal to obtain a first output signal;

[0047] In response to the control of the multi-channel power distribution unit by the multi-channel distribution signal, the first output signal is converted into multiple output signals, and the multiple output signals are respectively output from the multi-channel output ends, wherein each channel of the power distribution unit includes: a first transistor and a second transistor connected back to back, and each channel of the distribution signal is used to control the switching state of the first transistor and the second transistor of the corresponding channel.

[0048] The beneficial effects of this application include at least:

[0049] The embodiment of the present application is arranged in a multi-channel output mode of a multi-channel switching power supply, and the total power of the system is adjusted according to the output signal feedback of the first power distribution unit in the multi-channel power distribution unit, and the power distribution between the multi-channel output ends of the system is controlled according to the output signal feedback of other power distribution units in the multi-channel power distribution unit. Compared with the existing scheme, the multi-output switching power supply provided by the scheme of the present application only requires one set of power conversion modules, and mainly uses two low-voltage tubes (first transistor and second transistor) connected back to back as power distribution units. Therefore, in the power distribution process, there is no need to use multiple sets of inductance elements, which can improve the system working efficiency and reduce the heat generation and system cost during the system operation; at the same time, since the first transistor and the second transistor connected back to back have a higher secondary conversion efficiency for the total power of the system, it is also conducive to achieving greater power output.

[0050] In a further preferred example, since the body diodes of the first transistor and the second transistor are connected in reverse, no circulating current will occur between output ends of different paths, and different outputs can be controlled independently.

[0051] It should be noted that the above general description and the following detailed description are merely exemplary and explanatory and do not limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A structural block diagram of a multi-output switching power supply provided according to an embodiment of the present application is shown;

[0053] Figure 2 A schematic diagram of an implementation of a multi-output switching power supply provided according to a first embodiment of the present application is shown;

[0054] Figure 3 A schematic diagram showing an implementation of a multi-output switching power supply provided according to a second embodiment of the present application is shown;

[0055] Figure 4 A schematic diagram of an implementation of a control circuit provided according to an embodiment of the present application is shown;

[0056] Figure 5 A schematic diagram showing a timing waveform of a control signal of each transistor in a multi-output switching power supply with 2 outputs provided according to an embodiment of the present application;

[0057] Figure 6 A schematic diagram showing timing waveforms of voltages and output currents of some nodes in a multi-output switching power supply with two outputs provided according to an embodiment of the present application;

[0058] Figure 7 A schematic diagram showing a timing waveform of a control signal of each transistor in a multi-output switching power supply with three outputs provided according to an embodiment of the present application;

[0059] Figure 8 A schematic diagram showing timing waveforms of voltages and output currents of some nodes in a multi-output switching power supply with three outputs provided according to an embodiment of the present application;

[0060] Fig. 9 A flow chart of a control method for a multi-output switching power supply provided in accordance with an embodiment of the present application is shown. DETAILED DESCRIPTION

[0061] In order to facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0062] In the description of the present application, the words "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments. "And / or" in this article is a description of the association relationship of associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. "Multiple" refers to two or more than two. In addition, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, the words "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. Those skilled in the art can understand that the words "first" and "second" do not limit the quantity and execution order, and the words "first" and "second" do not limit them to be necessarily different. "Coupled" is a description of the connection relationship between associated objects. For example, A is coupled to B, which can indicate a direct connection between A and B, or an indirect connection between A and B through other devices / units / modules.

[0063] The transistor described in this article refers to all single components based on semiconductor materials, including diodes, triodes, field effect transistors, thyristors, etc. made of various semiconductor materials.

[0064] The “back-to-back connection” described herein refers to a connection method in which the anodes of the body diodes of two transistors are connected to each other so that the cathode terminals of the body diodes serve as signal input and output terminals.

[0065] In addition, the same figure marks in the figures represent the same or similar structures, and thus their repeated description will be omitted. That is, the various parts in this specification are described in a combination of parallel and progressive manners, and each part focuses on the differences from other parts. The same or similar parts between the various parts can be referenced to each other.

[0066] In the related art, the implementation schemes of multi-output switching power supply (taking dual-output switching power supply as an example) include the following:

[0067] Solution 1: Use an AC / DC module to convert input energy, and set up multiple buck circuits at the output stage of the AC / DC module to achieve multi-output output. Each output requires a buck circuit. The disadvantage is that each output requires a buck circuit, and a buck circuit usually includes two switching tubes, an inductor, and a control circuit. The system cost is high, and the buck circuit is inefficient and generates severe heat, which affects the user experience.

[0068] Solution 2: Use an AC / DC module to convert input energy, and its output is directly used as the output of one output terminal. The output of the other output terminal is realized by setting a buck-boost circuit at the output stage of the AC / DC module. The disadvantage is that one of the output terminals needs to be set up with a buck-boost circuit, and a buck-boost circuit usually includes 4 switching tubes, an inductor and a control circuit. The system cost is high, and the charging efficiency of the output terminal with the buck-boost circuit is low, the heat is serious, and it cannot output a large power.

[0069] Solution 3: Set up two independent AC / DC modules to convert the input energy respectively, and use the outputs of the two AC / DC modules as the outputs of the two output terminals respectively. The disadvantage is that each output terminal corresponds to an AD / DC circuit, and each AC / DC circuit usually includes a transformer, a primary switch, a primary control circuit, an optocoupler, a secondary diode and a secondary control circuit, and the system cost is very high.

[0070] The embodiment of the present application provides a new multi-output switching power supply, which mainly uses two low-voltage tubes (a first transistor and a second transistor) connected back to back as a power distribution unit to achieve multi-channel output, so that there is no need to use inductive elements in the power distribution process, and a larger power output can be achieved. Therefore, the multi-output switching power supply provided by the embodiment of the present application can greatly improve the working efficiency of the multi-output switching power supply, and the heat generation and system cost during operation are very low.

[0071] refer to Figure 1 , Figure 2 and Figure 3 The multi-output switching power supply provided in the embodiment of the present application includes: a power conversion module 100, a multi-way power distribution unit and a control circuit 300. The power conversion module 100 receives an input signal, the multi-way power distribution unit is respectively coupled between the output end of the power conversion module 100 and the multi-way output end of the multi-output switching power supply, and the control circuit 300 is respectively coupled to the power conversion module 100 and the multi-way power distribution unit.

[0072] The power conversion module 100 performs power conversion on the input signal of the multi-output switching power supply according to the driving signal Vgs1 to obtain a first output signal. Optionally, the input signal described herein includes at least one of an input voltage Vin and an input current, and similarly, the output signal includes at least one of an output voltage and an output current. For ease of understanding, the following will only refer to the input signal and the output signal as an example.

[0073] The multi-channel power distribution unit is used to respond to the multi-channel distribution signal to convert the first output signal output by the power conversion module 100 into multiple output signals and distribute them to multiple output terminals. Each power distribution unit includes a first transistor and a second transistor connected back to back, and each distribution signal is used to control the switching state of the first transistor and the second transistor of the corresponding channel.

[0074] Optionally, the multiple output terminals include but are not limited to at least one of common output terminals such as a Type-A interface and a Type-C interface.

[0075] The control circuit 300 is used to generate a drive signal Vgs1 and output it to the power conversion module 100 based on the feedback of the output signal (such as output voltage or output current) of the first power distribution unit in the multi-way power distribution unit, and to generate a multi-way distribution signal and output it to the multi-way power distribution unit based on the feedback of the output signal (such as output voltage or output current) of other power distribution units except the first power distribution unit in the multi-way power distribution unit.

[0076] Optionally, in some examples, the control circuit 300 uses one of the fixed multiple power distribution units as the first power distribution unit; in other examples, the control circuit 300 may also use the power distribution unit with the largest output power as the first power distribution unit by comparing the output power of each power distribution unit.

[0077] In some examples, the control circuit 300 is further configured to generate a driving signal Vgs1 output to the power conversion module 100 according to an output signal feedback from an output terminal connected to a load device in a single-channel output mode.

[0078] The following is a detailed description of the present application scheme by taking a multi-output switching power supply with dual output terminals as an example. However, it should be understood that the present application scheme can also be applied to a multi-output switching power supply with three or more output terminals, as long as it complies with the basic inventive concept of the present application (i.e., using two transistors connected back-to-back to distribute power in the output path corresponding to each output interface).

[0079] In specific implementation, the input signal received by the power conversion module 100 can be a DC signal or an AC signal. And the circuit topology of the power conversion module 100 can be any isolated topology structure (such as forward, flyback, push-pull, etc.) or non-isolated topology structure (such as Buck type, Boost type, Buck-Boost type, etc.) that can realize the power conversion function.

[0080] exist Figure 1 , Figure 2 and Figure 3 In the example shown, the power conversion module 100 includes: a transformer TR having a primary winding Np and a secondary winding Ns, a main power tube Q1 located on the primary side of the transformer TR and coupled to the primary winding Np, and a rectifier tube Q2 and an output capacitor Co located on the secondary side of the transformer TR and coupled to the secondary winding Ns. The control end of the main power tube Q1 receives a drive signal Vgs1, and is used to perform power conversion on an input signal Vin of a multi-output switching power supply according to the drive signal Vgs1. The voltage on the secondary winding Ns of the transformer TR is rectified by the rectifier tube Q2 to obtain a first output signal. In some examples, the rectifier tube Q2 is connected between the secondary winding Ns and the ground terminal.

[0081] The main power tube Q1 and the rectifier tube Q2 are both high-voltage transistors that can withstand high voltage. Optionally, the main power tube Q1 is, for example, an NMOS field effect transistor, and the rectifier tube Q2 can be a diode or a synchronous rectifier switch tube. When the rectifier tube Q2 is selected as a synchronous rectifier switch tube, the power conversion module 100 also includes a synchronous rectifier control circuit (not shown in the figure) that provides a control signal to the rectifier tube Q2.

[0082] It should be noted that, based on the simplicity of the accompanying drawings, Figure 1 , Figure 2 and Figure 3 Only the main part of the power conversion module 100 is shown in the figure, and the specific structure of the power conversion module 100 can be understood by referring to relevant existing solutions.

[0083] Each power distribution unit includes two low-voltage transistors connected back to back, namely, a first transistor and a second transistor. It should be noted that the high-voltage transistor and the low-voltage transistor described in this article are relative concepts. For example, the main power tube Q1 and the rectifier tube Q2 are high-voltage transistors relative to the first transistor and the second transistor in each power distribution unit, and the first transistor and the second transistor are low-voltage transistors relative to the main power tube Q1 and the rectifier tube Q2.

[0084] In some examples, the first transistor and the second transistor are switch transistors, in which case the first transistor and the second transistor are coupled in series between the output end of the power conversion module 100 and the corresponding output end of the multiple output ends of the multi-output switching power supply, the cathode of the body diode of the first transistor is coupled to the output end of the power conversion module 100, and the cathode of the body diode of the second transistor is coupled to the corresponding output end of the multiple output ends. Accordingly, each distribution signal includes a first distribution signal and a second distribution signal, the control end of the first transistor in each power distribution unit receives the first distribution signal in the distribution signal of the corresponding path, and the control end of the second transistor in each power distribution unit receives the second distribution signal in the distribution signal of the corresponding path.

[0085] In other examples, the first transistor is a switch tube, and the second transistor is a diode. In this case, the first transistor and the second transistor are cascade-coupled between the output end of the power conversion module 100 and the corresponding output end of the multi-channel output end of the multi-output switching power supply, the cathode of the body diode of the first transistor is coupled to the output end of the power conversion module 100, the anode of the diode (the second transistor) is coupled to the anode of the body diode of the first transistor, and the cathode of the diode (the second transistor) is coupled to the corresponding output end of the multi-channel output end. Accordingly, the control end of the first transistor receives the distribution signal of the corresponding channel.

[0086] When the first transistor and the second transistor are switching tubes, the multi-way distribution signal output by the control circuit 300 will be used to control the first transistor in each power distribution unit to be alternately turned on; and to control the second transistor in each power distribution unit to be turned on or continuously turned off during the conduction period of the first transistor in the power distribution unit of the corresponding path.

[0087] When the first transistor is a switch tube and the second transistor is a diode, the multi-channel distribution signal output by the control circuit 300 only needs to control the first transistor in each power distribution unit to be alternately turned on.

[0088] Furthermore, the magnitude of the output signal of each power distribution unit is positively correlated with the conduction time of the first transistor in the power distribution unit.

[0089] In some preferred examples, the control circuit 300 further configures a dead time between the first transistor in each power distribution unit and the second transistor in the next power distribution unit that is turned on adjacently, so that a circulating current can be avoided between the first power distribution unit 210 and the second power distribution unit 220 during the voltage stabilization output process.

[0090] In some preferred examples, the control circuit 300 is further configured to have overlapping conduction time between two first transistors in two adjacent power distribution units, so as to avoid voltage overshoot at node A during the process of voltage regulation output.

[0091] refer to Figure 1 , Figure 2 and Figure 3 The working principle of the multi-output switching power supply is described below by taking an example in which a multi-way power distribution unit includes a first power distribution unit 210 and a second power distribution unit 220, and the first transistor and the second transistor in each power distribution unit are switching tubes.

[0092] For the convenience of distinction, the first transistor and the second transistor in the second power distribution unit 220 are respectively recorded as transistor Q11 and transistor Q12, and the first transistor and the second transistor in the first power distribution unit 210 are respectively recorded as transistor Q13 and transistor Q14. In other words, transistor Q11 corresponds to the first transistor in the second power distribution unit 220, transistor Q12 corresponds to the second transistor in the second power distribution unit 220, transistor Q13 corresponds to the first transistor in the first power distribution unit 210, and transistor Q14 corresponds to the second transistor in the first power distribution unit 210. The control end of transistor Q11 receives the distribution signal Vgs11, the control end of transistor Q12 receives the distribution signal Vgs12, the control end of transistor Q13 receives the distribution signal Vgs13, and the control end of transistor Q14 receives the distribution signal Vgs14.

[0093] Exemplarily, taking the case that transistor Q11, transistor Q12, transistor Q13 and transistor Q14 are all NMOS field effect transistors, their respective body diodes can be represented as D11, D12, D13 and D14, respectively. Among them, the cathode of the body diode of the first transistor corresponds to the drain of the NMOS field effect transistor, the anode of the body diode of the first transistor corresponds to the source of the NMOS field effect transistor, the anode of the body diode of the second transistor corresponds to the source of the NMOS field effect transistor, and the cathode of the body diode of the second transistor corresponds to the drain of the NMOS field effect transistor. Of course, in other embodiments of the present application, transistor Q11, transistor Q12, transistor Q13 and transistor Q14 can also be all or partly selected from PMOS field effect transistors or other types of transistors.

[0094] In this embodiment, the control circuit 300 includes: a distribution control module 310 and a driving control module 330 .

[0095] When the multi-output switching power supply has dual output terminals, that is, when the multi-way power distribution unit includes the first power distribution unit 210 and the second power distribution unit 220, the distribution control module 310 is used to generate a first error adjustment signal based on the output signal (such as the output voltage Vo1 or the output current Io1) of the first power distribution unit 210 and transmit it to the drive control module 330, and the drive control module 330 generates a drive signal Vgs1 based on the first error adjustment signal to control the switching state of the main power tube Q1 in the power conversion module 100; at the same time, the distribution control module 310 is also used to generate a second error adjustment signal based on the output signal (such as the output voltage Vo2 or the output current Io2) of the second power distribution unit 220, generate a first conduction time indication signal based on the second error adjustment signal, and generate a multi-way distribution signal after performing a logic operation on the first conduction time indication signal, the conduction indication signal of the main power tube and the shutdown indication signal of the main power tube to control the switching state of each transistor in the multi-way power distribution unit. Among them, the first on-time indication signal is used to indicate that the expected on-time of the first transistor (transistor Q11) in the second power distribution unit 220 in the current control cycle is the first on-time (denoted as ton), that is, the expected on-time of the transistor Q11 after the main power tube Q1 is turned off. The size of the first on-time is controlled according to the second error adjustment signal. The on-time indication signal of the main power tube represents the on-time of the main power tube Q1, and the off-time indication signal of the main power tube represents the off-time of the main power tube Q1.

[0096] In some examples, the distribution control module 310 transmits the first error adjustment signal to the drive control module 330 through the isolation device 320. For example, when the power conversion module 100 is an isolated topology, the distribution control module 310 is located on the secondary side of the power conversion module 100, and the drive control module 330 is located on the primary side of the power conversion module 100, and the two communicate signals through the isolation device 320. The specific structure of the drive control module 330 can be understood by referring to the relevant existing solutions, which will not be described in detail here.

[0097] Further, refer to Figure 4 The allocation control module 310 specifically includes: a first error amplification unit 311 , a second error amplification unit 312 , a modulation unit 313 and an access detection unit 314 .

[0098] Among them, the first error amplification unit 311 is used to perform error amplification on the feedback signal VFB1 of the output voltage of the first power distribution unit 210 and the first reference voltage signal Vo1_ref, or to perform error amplification on the feedback signal IFB1 of the output current of the first power distribution unit 210 and the first reference current signal Io1_ref, to generate a first error adjustment signal, and transmit it to the drive control module 330 through the isolation device 320.

[0099] In some examples, the first error amplifier unit 311 includes, for example, an error amplifier 315 and an error amplifier 316, wherein a first input terminal of the error amplifier 315 receives a feedback signal VFB1, a second input terminal of the error amplifier 315 receives a first reference voltage signal Vo1_ref, a first input terminal of the error amplifier 316 receives a feedback signal IFB1, a second input terminal of the error amplifier 316 receives a first reference current signal Io1_ref, and an output terminal of the error amplifier 315 is coupled to an output terminal of the error amplifier 316. Further, a resistor R31 and a capacitor C31 are coupled in series between the first input terminal and the output terminal of the error amplifier 315, and a resistor R32 and a capacitor C32 are coupled in series between the first input terminal and the output terminal of the error amplifier 316. The first error amplifier unit 311 outputs a first error adjustment signal through the error amplifier 315 and the error amplifier 316.

[0100] Take the isolation device 320 as an optical coupler isolation device as an example. Figure 2 and Figure 3 As shown, the isolation device 320 includes an optocoupler diode D2 and a resistor R3. Figure 2In the example shown, the rectifier tube Q2 is a diode, and the cathode of the optocoupler diode D2 is coupled to the distribution control module 310 to receive the first error adjustment signal, and the anode of the optocoupler diode D2 is coupled to the output node of the first power distribution unit 210 through the resistor R3. Figure 3 In the example shown, the rectifier tube Q2 is a synchronous rectifier switch tube, and at this time, the anode of the optocoupler diode D2 is coupled to the distribution control module 310 to receive the first error adjustment signal, and the cathode of the optocoupler diode D2 is coupled to the reference ground through the resistor R3. In addition, when the rectifier tube Q2 is a synchronous rectifier switch tube, the current zero-crossing point of the first power distribution unit 210 and the second power distribution unit 220 can also be obtained through the control signal Vgs2 of the synchronous rectifier switch tube.

[0101] The second error amplifying unit 312 is used to perform error amplification on the feedback signal VFB2 of the output voltage of the second power distribution unit 220 and the second reference voltage signal Vo2_ref, or to perform error amplification on the feedback signal IFB2 of the output current of the second power distribution unit 220 and the second reference current signal Io2_ref, to generate a second error adjustment signal, and to generate a first conduction time indication signal according to the second error adjustment signal.

[0102] Furthermore, the multi-output switching power supply provided in the embodiment of the present application is also provided with a resistor R1 between the output end of the first power distribution unit 210 and the corresponding first output end 400, and a resistor R2 is also provided between the output end of the second power distribution unit 220 and the corresponding second output end 500. The distribution control module 310 can, for example, obtain the output voltage feedback signal VFB1 and the output current feedback signal IFB1 of the first power distribution unit 210 by sampling the voltage signal across the resistor R1, and can obtain the output voltage feedback signal VFB2 and the output current feedback signal IFB2 of the second power distribution unit 220 by sampling the voltage signal across the resistor R2.

[0103] The modulation unit 313 is coupled to the second error amplification unit 312, and is used to sample the output voltage Vdrain of the power conversion module 100 to detect the turn-on and turn-off times of the main power tube Q1 in the power conversion module 100, and generate a multi-channel distribution signal (including generating a distribution signal Vgs11, a distribution signal Vgs12, a distribution signal Vgs13 and a distribution signal Vgs14) according to the detection result and the first turn-on time indication signal.

[0104] The access detection unit 314 is used to detect the access status of load devices at multiple output ends, and indicates that the current mode is multi-channel output when it is detected that at least two output ends have load devices connected, and indicates that the current mode is single-channel output when it is detected that one output end has a load device connected.

[0105] Further, the multi-output switching power supply provided in the embodiment of the present application also includes: a switch connection path is also provided between the output end of each power distribution unit and the corresponding load connection end, and is turned on when a load device is connected to the corresponding coupled output end, thereby connecting the switch connection path. For example, a transistor Q3 is also provided between the output end of the first power distribution unit 210 and the corresponding first output end 400, and a transistor Q4 is also provided between the output end of each second power distribution unit 220 and the corresponding second output end 500, the transistor Q3 is coupled in series between the resistor R1 and the first output end 100, and the transistor Q4 is coupled in series between the resistor R2 and the second output end 500. The control ends of the transistor Q3 and the transistor Q4 are both coupled to the access detection unit 314, and are configured to be turned on when a load device is connected to the corresponding coupled output end, thereby connecting the output path.

[0106] In a further embodiment, the access detection unit 314 is further used to determine the charging protocol applicable to the output end according to the charging information fed back by the load device when a load device is connected to the output end. On this basis, the distribution control module 310 is also used to control the power distribution of the output power of the power conversion module 100 between multiple output ends according to the charging protocol determined by the access detection unit 314, so that the voltage and current distributed to each output path can meet the charging protocol.

[0107] In some preferred embodiments, the multi-output switching power supply further includes a voltage overshoot protection unit 340, such as Figure 2 and Figure 3 As shown, the voltage overshoot protection unit 340 is coupled to the output end (i.e., node A) of the power conversion module 100, and is used to absorb energy at the connection node A during the startup process of the multi-output switching power supply, so as to control the first output signal output by the power conversion module 100 within a certain range, thereby preventing a voltage overshoot from occurring at the connection node A during the startup process.

[0108] exist Figure 2 or Figure 3 In the example shown, the voltage overshoot protection unit 340 specifically includes: a diode D1 and a capacitor C3, wherein the anode of the diode D1 is coupled to the node A, and the cathode is coupled to the reference ground through the first capacitor C3. A supply voltage VCC required for the distribution control module 310 to work is also generated at the connection node between the diode D1 and the capacitor C3.

[0109] Furthermore, the multi-output switching power supply is also provided with an output capacitor for each output path, including a capacitor C1 coupled between the output end of the first power distribution unit 210 and the reference ground, and a capacitor C2 coupled between the output end of the second power distribution unit 220 and the reference ground.

[0110] refer to Figure 2 , Figure 3 and Figure 4 The distribution control module 310 includes: a power supply pin VCC, a voltage sampling pin VD1, a voltage sampling pin VD2, a voltage sampling pin VD3, a voltage sampling pin VD4, a voltage sampling pin Vdrain, a voltage detection pin VIN1, a voltage detection pin VIN2, a current detection pin CSP1, a current detection pin CSN1, a current detection pin CSP2, a current detection pin CSN2, an optocoupler isolation pin OPTO, a control pin Vgs11, a control pin Vgs12, a control pin Vgs13, a control pin Vgs14, a control pin Vgs3 and a control pin Vgs4.

[0111] The power supply pin VCC receives the power supply voltage VCC; the voltage sampling pin VD1 is coupled to the drain of the transistor Q11 to sample the first voltage VD1 of the drain of the transistor Q11; the voltage sampling pin VD2 is coupled to the drain of the transistor Q12 to sample the second voltage VD2 of the drain of the transistor Q12; the voltage sampling pin VD3 is coupled to the drain of the transistor Q13 to sample the third voltage VD3 of the drain of the transistor Q13; the voltage sampling pin VD4 is coupled to the drain of the transistor Q14 to sample the fourth voltage VD4 of the drain of the transistor Q14; the voltage sampling pin VD5 is coupled to the drain of the transistor Q15 to sample the fourth voltage VD5 of the drain of the transistor Q15; the voltage sampling pin VD6 is coupled to the drain of the transistor Q16 to sample the fourth voltage VD6 of the drain of the transistor Q16; the voltage sampling pin VD7 is coupled to the drain of the transistor Q17 to sample the fourth voltage VD7 of the drain of the transistor Q17; the voltage sampling pin VD8 is coupled to the drain of the transistor Q18 to sample the fourth voltage VD8 of the drain of the transistor Q18; the voltage sampling pin VD9 is coupled to the drain of the transistor Q19 to sample the fourth voltage VD9 of the drain of the transistor Q19; the voltage sampling pin VD10 is coupled to the drain of the transistor Q19 to sample the fourth voltage VD10 of the drain of the transistor Q19; the voltage sampling pin VD11 is coupled to the drain of the transistor Q19 to sample the first voltage VD11 of the transistor Q19; the voltage sampling pin VD21 is coupled to the drain of the transistor Q19 to sample the second voltage VD2 of the drain of the transistor Q19; the voltage sampling pin VD31 is coupled to the drain of the transistor Q19 to sample the third voltage VD3 of the drain of the transistor Q19; the voltage sampling pin VD42 is coupled to the drain of the transistor Q19 to sample the fourth voltage VD The pin Vdrain is coupled to the secondary winding Ns to sample the output voltage Vdrain of the power conversion module 100; the voltage detection pin VIN1 is coupled to the output end of the first power distribution unit 210 to sample the output voltage Vo1 of the first power distribution unit 210; the voltage detection pin VIN2 is coupled to the output end of the second power distribution unit 220 to sample the output voltage Vo2 of the second power distribution unit 220; the current detection pin CSP1 is coupled to the first end of the resistor R1, and the current detection pin CSN1 is coupled to the second end of the resistor R1 to sample the output voltage Vo2 of the second power distribution unit 220. The output current Io1 of the first power distribution unit 210; the current detection pin CSP2 is coupled to the first end of the resistor R2, and the current detection pin CSN2 is coupled to the second end of the resistor R2 to sample the output current Io2 of the second power distribution unit 220; the isolation transmission pin OPTO is coupled to the isolation device 320 to transmit the first error adjustment signal to the drive control module 330 through the isolation device 320; the control pin Vgs11 is coupled to the control end of the transistor Q11 to send the distribution signal Vgs11 to the transistor Q11; the control pin Vgs12 is coupled to the transistor The control end of Q12 is coupled to send a distribution signal Vgs12 to transistor Q12; the control pin Vgs13 is coupled to the control end of transistor Q13 to send a distribution signal Vgs13 to transistor Q13; the control pin Vgs14 is coupled to the control end of transistor Q14 to send a distribution signal Vgs14 to transistor Q14; the control pin Vgs3 is coupled to the control end of transistor Q3 to send a control signal Vgs3 to transistor Q3; the control pin Vgs4 is coupled to the control end of transistor Q4 to send a control signal Vgs4 to transistor Q4.

[0112] In this embodiment, the distribution control module 310 is configured to control the first transistor (transistor Q11) in the second power distribution unit 220 to turn on during the conduction period of the main power tube Q1; after the first transistor in the second power distribution unit 220 is turned on and overlaps the conduction time (recorded as Tg1_on_delay), the first transistor (transistor Q13) in the first power distribution unit 210 is controlled to turn on; after the first time when the main power tube Q1 is turned off, the first transistor (transistor Q13) in the first power distribution unit 210 is controlled to turn on; after the second time when the main power tube Q1 is turned off, the first transistor (transistor Q11) in the second power distribution unit 220 is controlled to turn off. The second time is greater than the first time, so as to achieve the alternating conduction control of the transistor Q11 and the transistor Q13.

[0113] The distribution control module 310 is also configured to use different control strategies to control the on and off of each transistor in the multi-way power distribution unit within different ranges of the first on time ton indicated by the on time indication signal, so as to ensure that the optimal distribution strategy can be implemented for the output power of the power conversion module 100.

[0114] Combination Figure 5 and Figure 6 Taking the multi-way power distribution unit including the first power distribution unit 210 and the second power distribution unit 220 as an example, the control strategy of the distribution control module 310 in different ranges of the first on-time ton includes:

[0115] When the first conduction time \(t_{on}\) is greater than a preset first time threshold (for example, equal to the sum of the preset minimum conduction time threshold (denoted as \(T_{on\_min}\)) and the preset dead time \(T_{death}\)) and less than a preset second time threshold (for example, equal to the preset maximum conduction time threshold (denoted as \(T_{on\_max}\))), that is, when \(T_{on\_min}+T_{death}<t_{on}<T_{on\_max}\), after the main power transistor \(Q1\) is turned off and before the transistor \(Q11\) is turned off, control the transistor \(Q12\) to conduct for a third time, and after the transistor \(Q11\) is turned off and before the transistor \(Q13\) is turned off, control the transistor \(Q14\) to conduct for a fourth time. At this time, the aforementioned first time is equal to the first conduction time \(t_{on}\) minus the overlapping conduction time \(T_{g3\_on\_delay}\), that is, the first time is equal to \(t_{on}-T_{g3\_on\_delay}\); the second time is equal to the first conduction time \(t_{on}\); the third time is equal to the first conduction time \(t_{on}\) minus the overlapping conduction time \(T_{g3\_on\_delay}\) and then minus the dead time \(T_{death}\), that is, the third time is equal to \(t_{on}-T_{g3\_on\_delay}-T_{death}\); the fourth time is equal to the time length between the turn-off moment of the transistor \(Q11\) and the first moment, and this first moment represents the moment when the drain voltage of the transistor \(Q14\) is greater than the drain voltage of the transistor \(Q13\), that is, the first moment represents the moment when the third voltage \(V_{D3}\) is less than the fourth voltage \(V_{D4}\).

[0116] When the first conduction time \(t_{on}\) is greater than or equal to the preset second time threshold, that is, \(t_{on}\geq T_{on\_max}\), after the main power transistor \(Q1\) is turned off and before the transistor \(Q11\) is turned off, control the transistor \(Q12\) to conduct for a third time, and control the transistor \(Q14\) to remain off. At this time, the aforementioned first time is equal to the sum of the third time and the dead time \(T_{death}\); the second time is equal to the sum of the third time, the dead time \(T_{death}\), and the overlapping conduction time \(T_{g3\_on\_delay}\); the third time is equal to the time length between the turn-off moment of the main power transistor \(Q1\) and the second moment, and this second moment represents the moment when the drain voltage of the transistor \(Q12\) is greater than the drain voltage of the transistor \(Q11\), that is, the second moment represents the moment when the first voltage \(V_{D1}\) is less than the second voltage \(V_{D2}\).

[0117] When the first on - time \(t_{on}\) characterized by the on - time indication signal is less than or equal to the preset first time threshold, that is, when \(t_{on}\leq T_{on - min}+T_{death}\), control the transistor \(Q12\) to remain off. And after the transistor \(Q11\) turns off and before the transistor \(Q13\) turns off, control the transistor \(Q14\) to conduct for a fourth time. At this time, the aforementioned first time is equal to zero; the second time is equal to the overlap on - time \(T_{g3 - on - delay}\); the fourth time is equal to the time length between the turn - off moment of the transistor \(Q11\) and the first moment, and the first moment represents the moment when the drain - terminal voltage of the transistor \(Q14\) is greater than the drain - terminal voltage of the transistor \(Q13\), that is, the first moment represents the moment when the third voltage \(V_{D3}\) is less than the fourth voltage \(V_{D4}\).

[0118] It should be noted that the overlap on - time \(T_{g1 - on - delay}\) and the overlap on - time \(T_{g3 - on - delay}\) can be the same time value or different time values. The so - called alternate conduction in this article means that their conduction actions and / or turn - off actions are alternated, rather than one conducting after the other turns off.

[0119] In some specific embodiments, in combination with Figure 2-Figure 6 , when \(T_{on - min}+T_{death}<t_{on}<T_{on - max}\), the allocation control module 310 is configured as follows:

[0120] During the period (i.e., \(t0 - t2\)) when the turn - on moment of the main power transistor \(Q1\) is detected and the turn - off moment of the main power transistor \(Q1\) has not been detected, output a valid (such as having a high level) allocation signal \(V_{gs11}\) to the second power allocation unit 220 to control the transistor \(Q11\) to conduct. Preferably, to ensure the accuracy and simplicity of control, the transistor \(Q11\) can be controlled to conduct when the turn - on moment of the main power transistor \(Q1\) (i.e., at the moment \(t0\)) is detected;

[0121] After the overlap on - time \(T_{g1 - on - delay}\) when the transistor \(Q11\) conducts, such as at the moment \(t1\), output an invalid (such as having a low level) allocation signal \(V_{gs13}\) to the first power allocation unit 210 to control the transistor \(Q13\) to turn off;

[0122] Start timing after detecting the turn - off moment of the main power transistor \(Q1\) (i.e., at the moment \(t2\)), and at the same time output a valid allocation signal \(V_{gs12}\) to the second power allocation unit 220 to control the transistor \(Q12\) to conduct;

[0123] After the timing value reaches the difference between the first on-time ton and the dead time Tdeath and the first overlapped on-time Tg3_on_delay (i.e., ton-Tdeath-Tg3_on_delay), at time t3, an invalid distribution signal Vgs12 is output to the second power distribution unit 220 to control the transistor Q12 to turn off;

[0124] After the timing value reaches the difference between the first on-time ton and the first overlapping on-time Tg3_on_delay (ie, ton-Tg3_on_delay), such as at time t4, a valid distribution signal Vgs13 is output to the first power distribution unit 210 to control the transistor Q13 to be turned on;

[0125] After the timing value reaches the first on-time ton, such as at time t5, an invalid distribution signal Vgs11 is output to the second power distribution unit 220 to control the transistor Q11 to turn off;

[0126] After the dead time Tdeath when the transistor Q11 is turned off, such as at time t6, a valid distribution signal Vgs14 is output to the first power distribution unit 210 to control the transistor Q14 to be turned on;

[0127] After detecting that the difference between the third voltage VD3 and the fourth voltage VD4 is less than zero, such as at time t7, an invalid distribution signal Vgs14 is output to the first power distribution unit 210 to control the transistor Q14 to turn off.

[0128] In some specific implementations, when ton≥Ton_max, the modulation unit 313 is configured as follows:

[0129] When the turn-on moment of the main power tube Q1 is detected and the turn-off moment of the main power tube Q1 has not been detected, in this time period (i.e., t0-t2), a valid (such as a high level) distribution signal Vgs11 is output to the second power distribution unit 220 to control the transistor Q11 to be turned on. Preferably, in order to ensure the accuracy and simplicity of control, the transistor Q11 can be controlled to be turned on when the turn-on moment of the main power tube Q1 (i.e., moment t0) is detected;

[0130] After the overlapping on-time Tg1_on_delay of the transistor Q11 being turned on, such as at time t1, an invalid distribution signal Vgs13 (such as having a low level) is output to the first power distribution unit 210 to control the transistor Q13 to be turned off;

[0131] After detecting the turn-off time of the main power tube (i.e., time t2), the timing starts, and at the same time, a valid distribution signal Vgs12 is output to the second power distribution unit 220 to control the transistor Q12 to turn on;

[0132] After detecting that the difference between the first voltage VD1 and the second voltage VD2 is less than zero, outputting an invalid distribution signal Vgs12 to the second power distribution unit 220 to control the transistor Q12 to turn off;

[0133] After the dead time Tdeath when the transistor Q12 is turned off, a valid distribution signal Vgs13 is output to the first power distribution unit 210 to control the transistor Q13 to be turned on;

[0134] After the first overlapping on-time Tg3_on_delay during which the transistor Q13 is turned on, the inactive distribution signal Vgs11 is output to the second power distribution unit 220 to control the transistor Q11 to be turned off.

[0135] In some specific implementations, when ton≤Ton_min+Tdeath, the modulation unit 313 is configured as follows:

[0136] When the turn-on moment of the main power tube Q1 is detected and the turn-off moment of the main power tube Q1 has not been detected, in this time period (i.e., t0-t2), a valid (such as a high level) distribution signal Vgs11 is output to the second power distribution unit 220 to control the transistor Q11 to be turned on. Preferably, in order to ensure the accuracy and simplicity of control, the transistor Q11 can be controlled to be turned on when the turn-on moment of the main power tube Q1 (i.e., moment t0) is detected;

[0137] After the overlapping on-time Tg1_on_delay of the transistor Q11 being turned on, such as at time t1, an invalid distribution signal Vgs13 (such as having a low level) is output to the first power distribution unit 210 to control the transistor Q13 to be turned off;

[0138] After detecting the turn-off time of the main power tube (i.e. time t2), the timing starts, and at the same time, a valid distribution signal Vgs13 is output to the first power distribution unit 210 to control the transistor Q13 to turn on;

[0139] After the first overlapping on-time Tg3_on_delay of the transistor Q13 being turned on, an invalid distribution signal Vgs11 is output to the second power distribution unit 220 to control the transistor Q11 to be turned off;

[0140] After the dead time Tdeath when the transistor Q11 is turned off, a valid distribution signal Vgs14 is output to the first power distribution unit 210 to control the transistor Q14 to be turned on;

[0141] After detecting that the difference between the third voltage VD3 and the fourth voltage VD4 is less than zero, such as at time t6, an invalid distribution signal Vgs14 is output to the first power distribution unit 210 to control the transistor Q14 to turn off.

[0142] Further, when the multi-output switching power supply has three output ends, that is, the multi-way power distribution unit in the multi-output switching power supply includes a first power distribution unit, a second power distribution unit and a third power distribution unit corresponding to the three output ends respectively. Also, taking the first transistor and the second transistor in each power distribution unit as a switch tube as an example, at this time, the distribution control module 310 in the control circuit 300 will be configured to generate a first error adjustment signal according to the output signal feedback of the first power distribution unit and transmit it to the drive control module 330. The drive control module 330 generates a drive signal according to the first error adjustment signal to control the switch state of the main power tube Q1 in the power conversion module 100; and the distribution control module 310 is also used to generate a second error adjustment signal according to the output signal feedback of the second power distribution unit, generate a third error adjustment signal according to the output signal feedback of the third power distribution unit, and generate three distribution signals according to the second error adjustment signal and the third error adjustment signal to respectively control the switch state of each transistor in the first power distribution unit, the second power distribution unit and the third power distribution unit. Among them, the first on-time indication signal is used to indicate the expected on-time of the first transistor in the second power distribution unit after the main power tube Q1 is turned off, the second on-time indication signal represents the expected on-time of the first transistor in the third power distribution unit in the current control cycle, the on-time indication signal of the main power tube represents the on-time of the main power tube Q1, and the off-time indication signal of the main power tube represents the off-time of the main power tube Q1.

[0143] For a multi-output switching power supply with 3 outputs, refer to Figure 7 and Figure 8 , wherein the distribution signal Vgs15 and the distribution signal Vgs16 correspond to the control signals of the first transistor and the second transistor in the third power distribution unit (not shown), respectively, and the current I3 corresponds to the output current waveform of the third power distribution unit (not shown). The working principle of the multi-output switching power supply with 3 outputs can be obtained by simply expanding the multi-output switching power supply with 2 outputs.

[0144] Those skilled in the art will appreciate that, inspired by the embodiments of the present application, the multi-channel output power supply may also be 4-channel, 5-channel or other multi-channel situations, and its control concept is the same as that of the present invention or is analogous to that of the present invention and is within the protection scope of the present invention.

[0145] It can be understood that, on the one hand, the solution of the present application optimizes the structure of a multi-output switching power supply, including in a multi-channel output mode of the multi-output switching power supply, a power distribution unit including a first transistor and a second transistor connected back to back (such as a transistor Q1 and a transistor Q2 connected back to back, a transistor Q3 and a transistor Q4 connected back to back) is provided on each output path to perform power distribution between multiple output terminals;

[0146] On the other hand, the present application scheme also optimizes the control scheme of the multi-output switching power supply, by feeding back the voltage and / or current of the first power distribution unit 210, and outputting the driving optocoupler after error operation amplification, so as to control the total power outputted by the primary side, and by feeding back the voltage and / or current of the second power distribution unit 220, and obtaining the first on-time ton of the first transistor in the second power distribution unit 220, namely the transistor Q1 after error operation amplification, thereby controlling the on and off of each transistor (such as Q1-Q4) in each power distribution unit according to the first on-time ton, the preset overlapping on-time Tg_on_delay and the dead time Tdeath, and the detection of the drain voltage of each transistor, and executing the control strategy within different ranges of the first on-time ton, so as to control the distribution of energy among multiple output ends;

[0147] Compared with the existing solutions, the solution of the present application does not need to use inductive elements or multiple sets of AC / DC circuits during the power distribution process. During the power distribution process, the turn-off loss of each transistor is smaller, the efficiency is higher, the heat is less, and the cost is lower. At the same time, power distribution is performed by using two transistors connected back to back, so that the output end can achieve a greater power output, thereby greatly improving the charging efficiency during multi-port charging and having stronger adaptability.

[0148] Furthermore, an embodiment of the present application also provides a charger, which includes the multi-output switching power supply disclosed in any of the aforementioned embodiments and can achieve the same technical effect.

[0149] Furthermore, the present application also provides a charging control method for a multi-output switching power supply, which can be applied to the multi-output switching power supply disclosed in any of the above embodiments. Fig. 9 , the charging control method comprises executing the following steps:

[0150] In step 910, a driving signal is generated according to the output signal feedback of the first power distribution unit in the multi-way power distribution unit, and a multi-way distribution signal is generated according to the output signal feedback of other power distribution units in the multi-way power distribution unit.

[0151] In step 920, power conversion is performed on an input signal of the multi-output switching power supply according to the driving signal to obtain a first output signal.

[0152] In step 930, in response to the control of the multi-way distribution signal on the multi-way power distribution unit, the first output signal is converted into multiple output signals, and the multiple output signals are respectively output from the multi-way output ends, wherein each power distribution unit includes a first transistor and a second transistor connected back to back, and each distribution signal is used to control the switching state of the first transistor and the second transistor of the corresponding path.

[0153] In specific implementation, the specific implementation of each step in the charging control method of the multi-output switching power supply described above and the corresponding technical effects that can be brought about can refer to the aforementioned embodiments of the multi-output switching power supply, which will not be repeated here.

[0154] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present application, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present application.

Claims

1. A multi-output switching power supply, comprising: A power conversion module, performing power conversion on an input signal of the multi-output switching power supply according to a driving signal to obtain a first output signal; A multi-way power distribution unit, respectively coupled between the output end of the power conversion module and the multi-way output end of the multi-output switching power supply, responding to a multi-way distribution signal to convert the first output signal into a plurality of output signals, the plurality of output signals are respectively output from the multi-way output end; The control circuit generates the driving signal according to the output signal feedback of the first power distribution unit in the multi-way power distribution unit, and generates multiple distribution signals according to the output signal feedback of other power distribution units in the multi-way power distribution unit, Each of the power distribution units comprises: a first transistor and a second transistor connected back to back, and each distribution signal is used to control the switching state of the first transistor and the second transistor of the corresponding path.

2. The multi-output switching power supply according to claim 1, wherein: The first transistor and the second transistor are low voltage transistors.

3. The multi-output switching power supply according to claim 2, wherein: The first transistor and the second transistor are switch tubes; A cathode of the body diode of the first transistor is coupled to the output terminal of the power conversion module, and a cathode of the body diode of the second transistor is coupled to a corresponding output terminal of the multiple output terminals; Each distribution signal includes a first distribution signal and a second distribution signal. The control end of the first transistor receives the first distribution signal of the corresponding distribution signal, and the control end of the second transistor receives the second distribution signal of the corresponding distribution signal.

4. The multi-output switching power supply according to claim 2, wherein: The first transistor is a switch tube, and the second transistor is a diode; The cathode of the body diode of the first transistor is coupled to the output terminal of the power conversion module, the anode of the diode is coupled to the anode of the body diode of the first transistor, and the cathode of the diode is coupled to a corresponding output terminal of the multiple output terminals; The control terminal of the first transistor receives the distribution signal of the corresponding path.

5. The multi-output switching power supply according to claim 3, wherein: The multiplexed distribution signals are configured as follows: Controlling the first transistor in each power distribution unit to be turned on alternately; The second transistor in each power distribution unit is controlled to be turned on or continuously turned off during the period when the first transistor in the power distribution unit of the corresponding path is turned on.

6. The multi-output switching power supply according to claim 4, wherein: The multiplexed distribution signals are further configured as: The first transistor in each power distribution unit is controlled to be turned on alternately.

7. The multi-output switching power supply according to claim 5 or 6, wherein: The magnitude of the output signal of each power distribution unit is positively correlated with the conduction time of the first transistor in the power distribution unit.

8. The multi-output switching power supply according to claim 5, wherein: There is a dead time between the first transistor in each power distribution unit and the second transistor in the next power distribution unit that is turned on.

9. The multi-output switching power supply according to claim 5 or 8, wherein: There is an overlapping conduction time between two first transistors in two adjacently turned-on power distribution units.

10. The multi-output switching power supply according to claim 9, wherein: The multi-channel power distribution unit comprises: the first power distribution unit and the second power distribution unit; The control circuit includes: a distribution control module and a drive control module; The distribution control module generates a first error adjustment signal according to the output signal feedback of the first power distribution unit and transmits the first error adjustment signal to the drive control module. The drive control module generates the drive signal according to the first error adjustment signal to control the switch state of the main power tube in the power conversion module. The distribution control module generates a second error adjustment signal according to the output signal feedback of the second power distribution unit, generates the first on-time indication signal according to the second error adjustment signal, and performs a logic operation on the first on-time indication signal, the on-indication signal of the main power tube and the off-indication signal of the main power tube to generate a plurality of distribution signals to control the switch state of each transistor in the multi-channel power distribution unit; The first on-time indication signal is used to indicate that the expected on-time of the first transistor in the second power distribution unit after the main power tube is turned off is the first on-time, and the size of the first on-time is controlled according to the second error adjustment signal.

11. The multi-output switching power supply according to claim 10, wherein: The distribution control module is configured to: Controlling the first transistor in the second power distribution unit to turn on during the conduction period of the main power tube; After the first transistor in the second power distribution unit is turned on for the overlapping conduction time, controlling the first transistor in the first power distribution unit to be turned off; After the main power tube is turned off for a first time, controlling the first transistor in the first power distribution unit to turn on; After the second time when the main power tube is turned off, the first transistor in the second power distribution unit is controlled to be turned off, The second time is greater than the first time.

12. The multi-output switching power supply according to claim 11, wherein: In a case where the first on-time is greater than a preset first time threshold and less than a preset second time threshold, the allocation control module is further configured to: After the main power tube is turned off and before the first transistor in the second power distribution unit is turned off, controlling the second transistor in the second power distribution unit to be turned on for a third time; After the first transistor in the second power distribution unit is turned off and before the first transistor in the first power distribution unit is turned off, controlling the second transistor in the first power distribution unit to be turned on for a fourth time; The first time threshold is equal to the sum of a preset minimum on-time threshold and a dead time, and the second time threshold is a preset maximum on-time threshold.

13. The multi-output switching power supply according to claim 11, wherein: In the case where the first on-time is greater than or equal to a preset second time threshold, the allocation control module is further configured to: After the main power tube is turned off and before the first transistor in the second power distribution unit is turned off, controlling the second transistor in the second power distribution unit to be turned on for a third time; controlling the second transistor in the first power distribution unit to be continuously turned off, The second time threshold is a preset maximum on-time threshold.

14. The multi-output switching power supply according to claim 11, wherein: When the first on-time is less than or equal to a preset first time threshold, the allocation control module is further configured to: Controlling the second transistor in the second power distribution unit to be continuously turned off; After the first transistor in the second power distribution unit is turned off and before the first transistor in the first power distribution unit is turned off, controlling the second transistor in the first power distribution unit to be turned on for a fourth time, The first time threshold is equal to the sum of a preset minimum on-time threshold and a dead time.

15. The multi-output switching power supply according to claim 9, wherein: The multi-channel power distribution unit comprises: the first power distribution unit, the second power distribution unit and the third power distribution unit; The control circuit includes: a distribution control module and a drive control module; The distribution control module generates a first error adjustment signal according to the output signal feedback of the first power distribution unit and transmits the first error adjustment signal to the drive control module. The drive control module generates the drive signal according to the first error adjustment signal to control the switch state of the main power tube in the power conversion module. The distribution control module generates a second error adjustment signal according to the output signal feedback of the second power distribution unit, generates a third error adjustment signal according to the output signal feedback of the third power distribution unit, and generates three distribution signals according to the second error adjustment signal and the third error adjustment signal to respectively control the switching state of each transistor in the first power distribution unit, the second power distribution unit and the third power distribution unit.

16. The multi-output switching power supply according to claim 1, wherein: The multi-output switching power supply further comprises: A voltage overshoot protection unit is coupled to the output end of the power conversion module and is used to control the first output signal within a certain range during the startup process of the multi-output switching power supply.

17. The multi-output switching power supply according to claim 1, wherein: The multi-output switching power supply further comprises: A switch connection path is also provided between the output end of each power distribution unit and the corresponding load connection end, and is turned on when a load device is connected to the corresponding coupled output end, thereby turning on the switch connection path.

18. The multi-output switching power supply according to claim 1, wherein: The power conversion module includes: a main power tube, a rectifier tube and a transformer; The main power tube is connected to the primary winding of the transformer, the rectifier tube is connected to the secondary winding of the transformer, and the voltage on the secondary winding of the transformer is rectified by the rectifier tube to obtain the first output signal; The main power tube and the rectifier tube are high-voltage transistors.

19. The multi-output switching power supply according to claim 18, wherein: The rectifier tube is connected between the secondary winding and the ground terminal.

20. A control method for a multi-output switching power supply, the multi-output switching power supply comprising a multi-way power distribution unit, the control method comprising: Generate a driving signal according to the output signal feedback of the first power distribution unit in the multi-way power distribution unit, and generate a multi-way distribution signal according to the output signal feedback of other power distribution units in the multi-way power distribution unit; Performing power conversion on an input signal of the multi-output switching power supply according to the driving signal to obtain a first output signal; In response to the control of the multi-channel power distribution unit by the multi-channel distribution signals, converting the first output signal into a plurality of output signals; Each of the power distribution units comprises: a first transistor and a second transistor connected back to back, and each distribution signal is used to control the switching state of the first transistor and the second transistor of the corresponding path.

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