Dual-output controllable flyback power supply and driving method thereof

Abstract

The application discloses a double-output controllable flyback power supply and a driving method thereof. The double-output controllable flyback power supply comprises an input module, an electromagnetic isolation module, a primary side switch, a first anti-reverse current module, a second anti-reverse current module, a first output module and a second output module. The electromagnetic isolation module comprises a first primary side winding, a first secondary side winding, a second primary side winding and a second secondary side winding. The first end of the primary side switch is connected with the first end of the input module. The first anti-reverse current module is connected between the second end of the input module and the second end of the primary side switch in series with the first primary side winding. The second anti-reverse current module is connected between the second end of the input module and the second end of the primary side switch in series with the second primary side winding. The application can realize the accurate control of the double-output power supply.

Description

Technical Field

[0001] This invention relates to the field of flyback power supply technology, and more particularly to a dual-output controllable flyback power supply and its driving method. Background Technology

[0002] Flyback converters have a simple topology and are widely used in low-power applications. They provide electrical isolation between the input and output stages, allowing low-power auxiliary power supplies composed of flyback converters to stably provide power to the electrical system.

[0003] However, current flyback power supplies mainly achieve controllable output voltage or current for a single output. Existing multi-output flyback power supplies only have precise control capability for the output voltage or current of a single output, meaning the main output can be precisely adjusted, while other auxiliary outputs rely solely on the isolation transformer windings and the load for linear adjustment. This power supply operation mode essentially results in an uncontrollable output state and a large range of output voltage variations. When the power requirements of the equipment increase or the load variation range is large, it is necessary to add a power regulation unit or pre-estimate the load capacity of the power supply. Otherwise, it will lead to a series of problems such as high power supply cross-regulation rate, poor system flexibility, and low reliability.

[0004] On the other hand, some dual-output controllable power supplies use a weighted voltage control method to time-multiplex two output branches. Both branches operate in discontinuous mode to reduce mutual cross-influence, but this will generate a large output voltage ripple, which will be aggravated as the load is adjusted.

[0005] Therefore, regardless of which of the above solutions is chosen, it undoubtedly increases the complexity of the power supply, reduces the flexibility and reliability of its operation, and further increases the design cost of the power supply. Summary of the Invention

[0006] This invention provides a dual-output controllable flyback power supply and its driving method to achieve precise control of the dual-output power supply, thereby improving the flexibility and controllability of operation.

[0007] In a first aspect, embodiments of the present invention provide a dual-output controllable flyback power supply, comprising: an input module, an electromagnetic isolation module, a primary-side switch, a first anti-reverse current module, a second anti-reverse current module, a first output module, and a second output module;

[0008] The input module is used to provide DC voltage; the electromagnetic isolation module includes a first primary winding, a first secondary winding, a second primary winding, and a second secondary winding.

[0009] The first output module is coupled to the first secondary winding and is used to generate a direct current on the first output module by using the energy released by the first primary winding and the first secondary winding during the primary switch being turned off.

[0010] The second output module is coupled to the second secondary winding and is used to generate a direct current on the second output module by the energy released by the second primary winding and the second secondary winding during the primary switch being turned off.

[0011] The first terminal of the primary-side switch is connected to the first terminal of the input module; the first anti-reverse current module is connected in series with the first primary-side winding and then connected between the second terminal of the input module and the second terminal of the primary-side switch; the second anti-reverse current module is connected in series with the second primary-side winding and then connected between the second terminal of the input module and the second terminal of the primary-side switch.

[0012] Optionally, the first end of the first anti-reverse current module is electrically connected to the second end of the input module, the second end of the first anti-reverse current module is electrically connected to the first end of the first primary winding, and the second end of the first primary winding is electrically connected to the second end of the primary switch; the first end of the second anti-reverse current module is electrically connected to the second end of the input module, the second end of the second anti-reverse current module is electrically connected to the first end of the second primary winding, and the second end of the second primary winding is electrically connected to the second end of the primary switch.

[0013] Alternatively, the first end of the first primary winding is electrically connected to the second end of the input module, the second end of the first primary winding is electrically connected to the first end of the first anti-reverse current module, and the second end of the first anti-reverse current module is electrically connected to the second end of the primary switch; the first end of the second primary winding is electrically connected to the second end of the input module, the second end of the second primary winding is electrically connected to the first end of the second anti-reverse current module, and the second end of the second anti-reverse current module is electrically connected to the second end of the primary switch.

[0014] Optionally, the dual-output controllable flyback power supply further includes a clamping module, which is connected between the second end of the input module and the second end of the primary-side switch, for absorbing and dissipating the energy of the leakage inductance of the first primary-side winding, and also for absorbing and dissipating the energy of the leakage inductance of the second primary-side winding.

[0015] Optionally, the clamping module includes a first clamping capacitor, a first clamping resistor, and a clamping diode; a first terminal of the first clamping capacitor is electrically connected to a second terminal of the input module, a second terminal of the first clamping capacitor is electrically connected to the cathode of the clamping diode, the first clamping resistor is connected in parallel with the first clamping capacitor, and the anode of the clamping diode is electrically connected to a second terminal of the primary-side switch.

[0016] Alternatively, the clamping module includes a second clamping capacitor, a second clamping resistor, and a clamping transistor. The first end of the second clamping capacitor is electrically connected to the second end of the input module, the second end of the second clamping capacitor is electrically connected to the first end of the clamping transistor, the second clamping resistor is connected in parallel with the second clamping capacitor, and the second end of the clamping transistor is electrically connected to the second end of the primary-side switch.

[0017] Optionally, the dual-output controllable flyback power supply further includes: a control module, which is used to acquire the output voltage or output current of the first output module and adjust the duty cycle of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the first output module;

[0018] The control module is also used to acquire the output voltage or output current of the second output module, and adjust the frequency of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the second output module.

[0019] Optionally, the control module includes:

[0020] The first sampling unit is electrically connected to the first output module and is used to collect the output voltage or output current of the first output module.

[0021] The second sampling unit is electrically connected to the second output module and is used to collect the output voltage or output current of the second output module.

[0022] A reference unit is used to generate a first reference voltage and a second reference voltage, or to generate a first reference current and a second reference current.

[0023] A first arithmetic unit, wherein a first input terminal of the first arithmetic unit is electrically connected to the first sampling unit, and a second input terminal of the first arithmetic unit is electrically connected to the first reference output terminal of the reference unit, is used to perform a first preset arithmetic operation;

[0024] The second arithmetic unit has a first input terminal electrically connected to the second sampling unit and a second input terminal electrically connected to the second reference output terminal of the reference unit, and is used to perform a second preset arithmetic operation.

[0025] A processing unit, configured to generate control signals based on the calculation results of the first arithmetic unit and the second arithmetic unit;

[0026] A modulation unit, wherein the modulation unit is used to adjust the duty cycle and frequency of the output modulation signal according to the control signal;

[0027] A driving unit is used to control the switching state of the primary-side switch according to the modulation signal.

[0028] Optionally, the control module further includes:

[0029] A drive protection unit is provided, which is used to detect the output voltage and output current of the input module and the modulation signal of the modulation unit, and generate a protection signal to control whether the drive unit outputs.

[0030] Optionally, the input module includes: an AC power supply, an input protection unit, an EMI filter unit, and a rectification filter unit;

[0031] The input protection unit is electrically connected to the AC power supply and is used to provide current and voltage protection for the AC power supply.

[0032] The EMI filtering unit is electrically connected to the input protection unit and is used to filter out electromagnetic interference;

[0033] The rectifier and filter module is electrically connected to the EMI filter unit and is used to rectify AC voltage into DC voltage.

[0034] Optionally, the primary-side switch is any one of a transistor, a metal-oxide-semiconductor field-effect transistor, a silicon carbide transistor, a gallium nitride transistor, a high electron mobility transistor, and an insulated-gate bipolar transistor.

[0035] Optionally, the first primary winding, the first secondary winding, the second primary winding, and the second secondary winding are integrated on the same transformer.

[0036] Secondly, embodiments of the present invention also provide a driving method for a dual-output controllable flyback power supply, wherein the dual-output controllable flyback power supply is the dual-output controllable flyback power supply described in the first aspect, and the driving method includes:

[0037] The duty cycle of the signal at the control terminal of the primary-side switch is adjusted according to the output voltage or output current of the first output module.

[0038] The frequency of the signal at the control terminal of the primary-side switch is adjusted according to the output voltage or output current of the second output module.

[0039] Optionally, the dual-output controllable flyback power supply further includes a control module, which is used to acquire the output voltage or output current of the first output module and the control module is also used to acquire the output voltage or output current of the second output module.

[0040] The driving method further includes:

[0041] The control module adjusts the duty cycle of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the first output module; the control module also adjusts the frequency of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the second output module.

[0042] The technical solution of this invention, by configuring the first primary winding to operate in continuous current mode and the second primary winding to operate in discontinuous current mode, allows for precise control of the output voltage or current of the first output module by adjusting the duty cycle of the primary-side switch signal. Furthermore, precise control of the output voltage or current of the second output module can be achieved by adjusting the switching frequency of the primary-side switch. Through dynamic adjustment of the duty cycle and frequency of the primary-side switch signal, the output voltage / current of both paths can be kept constant during changes in input voltage and / or output load, thus meeting the power requirements of downstream equipment or loads. Functional control enables precise control of both power supplies, reducing the cost and complexity of power supply design. Moreover, only one primary-side switch is needed to achieve precise control of both outputs, resulting in a simple structure and reduced power supply design complexity. Attached Figure Description

[0043] Figure 1 A schematic diagram of the circuit structure of a dual-output controllable flyback power supply provided in an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of the circuit structure of another dual-output controllable flyback power supply provided in an embodiment of the present invention;

[0045] Figure 3 A schematic diagram of the circuit structure of another clamping module provided in an embodiment of the present invention;

[0046] Figure 4 A schematic diagram of the circuit structure of another dual-output controllable flyback power supply provided in an embodiment of the present invention;

[0047] Figure 5 The experimental results of a dual-output controllable flyback power supply provided in an embodiment of the present invention are shown in the figure.

[0048] Figure 6 Experimental results of another dual-output controllable flyback power supply provided in an embodiment of the present invention;

[0049] Figure 7 This is a flowchart illustrating a driving method for a dual-output controllable flyback power supply provided in an embodiment of the present invention. Detailed Implementation

[0050] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention and not the entire structure.

[0051] Figure 1 This is a schematic diagram of the circuit structure of a dual-output controllable flyback power supply provided in an embodiment of the present invention, with reference to... Figure 1 The dual-output controllable flyback power supply includes: an input module 10, an electromagnetic isolation module 100, a primary-side switch S, a first anti-reverse current module D1, a second anti-reverse current module D2, a first output module 11, and a second output module 12. The input module 10 provides DC voltage. The electromagnetic isolation module includes a first primary winding, a first secondary winding, a second primary winding, and a second secondary winding. The first output module 11 is coupled to the first secondary winding and is used to generate energy from the energy released by the first primary winding and the first secondary winding during the primary-side switch S being turned off. A direct current; the second output module 12 is coupled to the second secondary winding to generate a direct current in the second output module 12 from the energy released by the second primary winding and the second secondary winding during the primary switch S being turned off; the first terminal of the primary switch S is electrically connected to the first terminal of the input module; the first anti-reverse current module Da1 is connected in series with the first primary winding and then connected between the second terminal of the input module 10 and the second terminal of the primary switch S; the second anti-reverse current module Da2 is connected in series with the second primary winding and then connected between the second terminal of the input module 10 and the second terminal of the primary switch S.

[0052] Specifically, such as Figure 1As shown, the first primary winding and the first secondary winding correspond to each other, and the first primary winding and the first secondary winding can be equivalent to a transformer, where Llkp1 is the leakage inductance of the first primary winding, Lm1 is the magnetizing inductance of the first primary winding, Np1 is the number of turns of the first primary winding, and Ns1 is the number of turns of the first secondary winding; the second primary winding and the second secondary winding correspond to each other, and the second primary winding and the second secondary winding can also be equivalent to a transformer, where Llkp2 is the leakage inductance of the second primary winding, Lm2 is the magnetizing inductance of the second primary winding, Np2 is the number of turns of the second primary winding, and Ns2 is the number of turns of the second secondary winding; exemplarily, the first output module 11 may include a first freewheeling diode D1, a first output capacitor Co1, and a first load RL1. The anode of the first freewheeling diode D1 is electrically connected to the first terminal of the first secondary winding, and the cathode of the first freewheeling diode D1 is connected to the first output capacitor Co1. The first terminal of the first primary winding is electrically connected, the second terminal of the first output capacitor Co1 is electrically connected to the second terminal of the first secondary winding, and the first load RL1 is connected in parallel with the first output capacitor Co1. The first primary winding is configured to operate in continuous current mode, where continuous current mode means that the combined ampere-turns of the first primary winding and the first secondary winding are not zero at any point in a switching cycle. When the primary switch S is turned on, a primary current gradually flows through the first primary winding, and energy is stored in the first primary winding. Since the polarities of the first primary winding and the first secondary winding are opposite, the first freewheeling diode D1 is not turned on at this time. The output power of the first output module 11 is provided by the first output capacitor Co1. At this time, for the first output circuit corresponding to the first output module, the first primary winding is equivalent to a series inductor with an inductance value of Llkp1 + Lm1. The current Ip1 of the first primary winding can be expressed as: The terminal voltage of the first secondary winding is the input module 10 minus the voltage drop of the first anti-reverse current module Da1, V p1 (t)=V in -V fanti1 Wherein, Vin is the DC voltage output by input module 10, and V... fanti1 The voltage drop across the first anti-reverse current module Da1; when the primary-side switch S is turned off, the voltage polarity on both the first primary winding and the first secondary winding reverses, causing the first freewheeling diode D1 to conduct. The energy stored in the first primary winding and the first secondary winding is then transferred to the first output capacitor Co1 and the first load RL1 through the first freewheeling diode D1. At this time, the terminal voltage of the first secondary winding is the sum of the first output voltage Vo1 and the voltage drop Vf1 of the first freewheeling diode D1: V s1 (t)=V o1 +V f1 The current in the first secondary winding can be expressed as: Where D is the duty cycle of the primary-side switch S, i.e., the ratio of the on-time of the primary-side switch S to the switching period T; Ls1 is the inductance of the first secondary-side winding, satisfying: n1 = Np1 / Ns1 is the turns ratio of the first primary winding to the first secondary winding; within one cycle of the primary switch S being turned on and off, the first primary winding and the first secondary winding satisfy volt-second balance, then: V p1 (t)×D×T×N s1 =V s1 (t)×(1-D)×T×N p1 Then we have: That is: Therefore, by adjusting the duty cycle D, the first output voltage can be precisely controlled; if the control target is the first output current, the relevant balance relationship can be obtained simply by symmetrically converting the voltage signal into a current signal.

[0053] Additionally, exemplarily, the second output module may include a second freewheeling diode D2, a second output capacitor Co2, and a second load RL2, wherein the anode of the second freewheeling diode D2 is electrically connected to the first terminal of the second secondary winding, the cathode of the second freewheeling diode D2 is electrically connected to the first terminal of the second output capacitor Co2, the second terminal of the second output capacitor Co2 is electrically connected to the second terminal of the second secondary winding, and the second load RL2 is connected in parallel with the second output capacitor Co2; the second primary winding is configured to operate in a discontinuous current operating mode, where the discontinuous current operating mode refers to the second primary winding and the second secondary winding... The synthesized ampere-turns are zero for a period of time during the off-side period of the primary-side switch S; when the primary-side switch S is turned on, a primary current gradually flows through the second primary-side winding, and energy is stored in the second primary-side winding. Since the polarities of the second primary-side winding and the second secondary-side winding are opposite, the second freewheeling diode D2 will not conduct at this time, and the second output power is provided by the second output capacitor Co2. At this time, for the second output circuit corresponding to the second output module, the second primary-side winding is equivalent to a series inductor with an inductance value of Llkp2 + Lm2. The current Ip2 of the second primary-side winding can be expressed as: The terminal voltage of the second secondary winding is the difference between the DC voltage output by input module 10 and the voltage drop Vfanti2 of the second anti-reverse current module Da2: V p2 (t)=V in -V fanti2 Among them, V fanti2This is the voltage drop across the second anti-reverse current module Da2. When the primary-side switch S is turned off, the voltage polarity on both the second primary winding and the second secondary winding reverses, forcing the second freewheeling diode D2 to conduct. The energy stored in the second primary winding and the second secondary winding is then transferred to the second output capacitor Co2 and the second load RL2 through the second freewheeling diode D2. At this time, the terminal voltage of the second secondary winding is the sum of the second output voltage Vo2 and the voltage drop Vf2 of the second freewheeling diode D2: V s2 (t)=V o2 +V f2 The current in the second secondary winding can be expressed as: Ls2 is the inductance of the second secondary winding, which satisfies: n2 = Np2 / Ns2 is the turns ratio of the second primary winding to the second secondary winding. At time DT, the current in the second secondary winding is at its maximum, i.e.: Where Io2 is the load current of the second load RL2, and f is the switching frequency of the primary-side switch S; the above operating state continues until t zero At a certain moment, when the energy stored in the second primary winding is completely released, and the primary switch S has not yet entered the next switching cycle, the current in both the second primary winding and the second secondary winding will drop to zero, and the second freewheeling diode D2 will naturally turn off, that is: Based on the above analysis, we can conclude that: During one cycle of the primary switch S being turned on and off, if the second primary winding and the second secondary winding also satisfy volt-second balance, then: V p2 (t)×D×T×N s2 =V s2 (t)×(t zero -DT)×N p2 Then we have: It can be seen that after the duty cycle stabilizes, the precise control of the second output voltage can be achieved by adjusting the switching frequency f of the primary-side switch S. Since the first output voltage value is independent of the switching frequency f, controlling the second output voltage will not affect the precise control of the first output voltage. Similarly, if the control target is the second output current, the relevant balance equation can be obtained simply by symmetrically converting the voltage signal into a current signal. Therefore, by configuring the first primary winding to operate in continuous current mode and the second primary winding to operate in discontinuous current mode, two output voltages can be precisely controlled by a single primary-side switch S. The output voltage of the first output module can be precisely controlled by the duty cycle of the control signal applied to the primary-side switch S, and the output voltage of the second output module can be precisely controlled by the frequency of the control signal applied to the primary-side switch S.

[0054] The technical solution of this embodiment can achieve precise control of the output voltage or output current of the first output module by adjusting the duty cycle of the primary-side switch signal. In addition, it can achieve precise control of the output voltage or output current of the second output module by adjusting the switching frequency of the primary-side switch. By dynamically adjusting the duty cycle and frequency of the primary-side switch signal, it is possible to flexibly and accurately maintain the constant output voltage / current of both paths during changes in input voltage and / or output load, so as to meet the power demand of downstream equipment or loads. Through functional control, precise controllability of the two power supplies can be achieved, reducing the cost and complexity of power supply design. In addition, only one primary-side switch is needed to achieve precise controllability of the two outputs, which is simple in structure and reduces the complexity of power supply design.

[0055] It should be noted that the second terminal of the input module 10 can be connected to the first ground signal GND1, the second terminal of the first secondary winding can be connected to the second ground signal GND2, and the second terminal of the second secondary winding can be connected to the third ground signal GND3. Any two of the first ground signal GND1, the second ground signal GND2, and the third ground signal GND3 can be the same ground signal or can be mutually isolated ground signals. The first freewheeling diode D1 and the second freewheeling diode D2 can also be rectifier switches. When rectifier switches are used, a specific switching signal needs to be given so that their conduction process is the same as that of the first freewheeling diode D1 and the second freewheeling diode D2.

[0056] Preferably, the primary-side switch S is any one of a transistor, a metal-oxide-semiconductor field-effect transistor, a silicon carbide transistor, a gallium nitride transistor, a high electron mobility transistor, and an insulated-gate bipolar transistor. This configuration saves costs while ensuring that the primary-side switch S can be efficiently turned on and off, guaranteeing the stability of the dual-output controllable flyback power supply.

[0057] Optionally, continue to refer to Figure 1 The first terminal of the first anti-reverse current module Da1 is electrically connected to the second terminal of the input module 10, the second terminal of the first anti-reverse current module Da1 is electrically connected to the first terminal of the first primary winding, and the second terminal of the first primary winding is electrically connected to the second terminal of the primary switch S; the first terminal of the second anti-reverse current module Da2 is electrically connected to the second terminal of the input module 10, the second terminal of the second anti-reverse current module Da2 is electrically connected to the first terminal of the second primary winding, and the second terminal of the second primary winding is electrically connected to the second terminal of the primary switch S;

[0058] Specifically, both the first anti-reverse current module Da1 and the second anti-reverse current module Da2 can be diodes. The first anti-reverse current module Da1 is used to prevent current on the second primary winding from flowing into the input module through the first primary winding, and the second anti-reverse current module Da2 is used to prevent current on the first primary winding from flowing into the input module through the second primary winding. The potential of the first terminal of the output voltage of the input module 10 is lower than the potential of the second terminal. At this time, the first terminal of the first anti-reverse current module Da1 is the anode of the diode, and the first terminal of the second anti-reverse current module Da2 is also the anode of the corresponding diode. The diode can be any one of a fast recovery diode, an ultra-fast recovery diode, a Schottky diode, a silicon carbide diode, and a gallium nitride diode. In this embodiment, the connection method can integrate the first anti-reverse current module Da1 and the second anti-reverse current module Da2 into the anti-reverse current module Danti, thereby improving the integration of the dual-output controllable flyback power supply. Preferably, in this embodiment, all power devices, such as the primary-side switch, can be group III nitride components, which can greatly improve the operating frequency of the power conversion device, reduce system losses, and reduce system size.

[0059] Furthermore, in this embodiment, the first primary winding, the second primary winding, the first secondary winding, and the second secondary winding are all integrated on the same transformer, thereby enabling the dual-output controllable flyback power supply to be divided into different modules and integrated separately, further improving the integration level.

[0060] Optionally, such as Figure 2 As shown, Figure 2 This is a schematic diagram of the circuit structure of another dual-output controllable flyback power supply provided in an embodiment of the present invention. In this embodiment, the first end of the first primary winding is electrically connected to the second end of the input module 10, the second end of the first primary winding is electrically connected to the first end of the first anti-reverse current module Da1, the second end of the first anti-reverse current module Da1 is electrically connected to the second end of the primary switch S, the second end of the second primary winding is electrically connected to the first end of the second anti-reverse current module Da2, and the second end of the second anti-reverse current module Da2 is electrically connected to the second end of the primary switch S.

[0061] Specifically, in this embodiment, the first anti-reverse current module Da1 and the second anti-reverse current module Da2 are connected in a common cathode manner, which can also achieve the effect of preventing the current on the second primary winding from flowing into the input module through the first primary winding and preventing the current on the first primary winding from flowing into the input module through the second primary winding.

[0062] Optionally, continue to refer to Figure 1 The dual-output controllable flyback power supply also includes a clamping module 101. The clamping module 101 is connected between the second end of the input module 10 and the second end of the primary-side switch S. It is used to absorb and consume the energy of the leakage inductance of the first primary-side winding and to absorb and consume the energy of the leakage inductance of the second primary-side winding.

[0063] Specifically, since both the first and second primary windings have leakage inductance, there will be a large spike voltage when the primary switch S is turned off. By setting up a clamping module, this part of the energy can be absorbed and consumed, thereby ensuring that the dual-output controllable flyback power supply can work normally.

[0064] For example, continue to refer to Figure 1 The clamping module 101 includes a first clamping capacitor Cclamp, a first clamping resistor Rclamp, and a clamping diode Dclamp. The first terminal of the first clamping capacitor Cclamp is electrically connected to the second terminal of the input module 10, the second terminal of the first clamping capacitor Cclamp is electrically connected to the cathode of the clamping diode Dclamp, the first clamping resistor Rclamp is connected in parallel with the first clamping capacitor Cclamp, and the anode of the clamping diode Dclamp is electrically connected to the second terminal of the primary-side switch S.

[0065] Specifically, when the primary-side switch S is turned off, the anode of the first clamping diode Dclamp is subjected to a high voltage and naturally conducts. The first clamping capacitor Cclamp begins to absorb excess energy from the leakage inductance of the first primary winding and the leakage inductance of the second primary winding, preventing the primary-side switch S from being subjected to a high voltage surge during the turn-off period. When the primary-side switch S is turned on, the anode of the first clamping diode Dclamp receives a low level and is automatically turned off. The first clamping capacitor Cclamp begins to release the previously absorbed energy through the first clamping resistor Rclamp, thereby preparing for the absorption of excess energy in the next switching cycle.

[0066] Exemplary, in some other implementations, such as Figure 3 As shown, Figure 3 This is a schematic diagram of the circuit structure of another clamping module provided in an embodiment of the present invention. The clamping module 101 includes a second clamping capacitor Cclamp1, a second clamping resistor Rclamp1, and a clamping transistor Sclamp. The first end of the second clamping capacitor Cclamp1 is electrically connected to the second end of the input module 10, the second end of the second clamping capacitor Cclamp1 is electrically connected to the first end of the clamping transistor Sclamp1, the second clamping resistor Rclamp is connected in parallel with the second clamping capacitor Cclamp1, and the second end of the clamping transistor Sclamp1 is electrically connected to the second end of the primary-side switch S.

[0067] Specifically, in this embodiment, a clamping transistor Sclamp is used to replace the clamping diode in the above embodiment, and the control signal applied to the control terminal of the clamping transistor Sclamp is opposite in polarity to the switching signal applied to the control terminal of the primary-side switch S. That is, when the primary-side switch S is turned on, the clamping transistor Sclamp is turned off, and when the primary-side switch S is turned off, the clamping transistor Sclamp is turned on. As a result, efficiency can be further improved and power consumption can be reduced.

[0068] Optionally, Figure 4 This is a schematic diagram of the circuit structure of another dual-output controllable flyback power supply provided in an embodiment of the present invention, referred to... Figure 4 The dual-output controllable flyback power supply also includes a control module 102. The control module 102 is used to acquire the output voltage or output current of the first output module and adjust the duty cycle of the signal at the control terminal of the primary-side switch S according to the output voltage or output current of the first output module. The control module 102 is also used to acquire the output voltage or output current of the second output module and adjust the frequency of the signal at the control terminal of the primary-side switch S according to the output voltage or output current of the second output module.

[0069] Specifically, in this embodiment, the control terminal of the primary-side switch S is electrically connected to the control module 102. By setting the control module 102, the dual-output controllable flyback power supply is configured to a closed-loop operating mode. The control module 102 configures the first target output voltage or the first target output current of the first output module, and configures the second target output voltage or the second target output current of the second output module. When it is detected that the actual output voltage of the first output module deviates from the first target output voltage by more than a preset value (e.g., 1%), or the actual output current of the first output module deviates from the first target output current by more than a preset value (e.g., 1%), the duty cycle of the switching signal on the primary-side switch S can be adjusted in a timely manner to stabilize the output voltage or output current of the first output module. When it is detected that the actual output voltage of the second output module deviates from the second target output voltage by more than a preset value (e.g., 1%), or the actual output current of the second output module deviates from the second target output current by more than a preset value (e.g., 1%), the frequency of the switching signal on the primary-side switch S can be adjusted in a timely manner to stabilize the output voltage or output current of the second output module.

[0070] Optionally, continue to refer to Figure 4The control module 101 includes a first sampling unit 1021, electrically connected to the first output module, for acquiring the output voltage Vo1 or output current of the first output module; a second sampling unit 1022, electrically connected to the second output module, for acquiring the output voltage Vo2 or output current of the second output module; a reference unit 1023, for generating a first reference voltage and a second reference voltage, or for generating a first reference current and a second reference current; and a first arithmetic unit 1024, the first input terminal of which is electrically connected to the first sampling unit 1021, and the second input terminal of which is electrically connected to the first reference output terminal of the reference unit 1023, for executing... The system performs a first preset operation; a second operation unit 1025, whose first input terminal is electrically connected to a second sampling unit 1022 and whose second input terminal is electrically connected to a second reference output terminal of a reference unit 1023, is used to perform a second preset operation; a processing unit 1026, which generates a control signal based on the operation results of the first operation unit 1024 and the second operation unit 1025; a modulation unit 1027, which adjusts the duty cycle and frequency of the output modulation signal according to the control signal; and a driving unit 1028, which controls the switching state of the primary-side switch S according to the modulation signal.

[0071] Specifically, the first preset operation and the second preset operation can both be, for example, difference operations. The first reference voltage and the second reference voltage output by the reference unit 1023 can be configured as needed, and this embodiment does not limit this. The first sampling unit 1021 samples the output voltage of the first output module and calculates the difference with the first reference voltage. After processing by the processing module 1026, the duty cycle value of the switching signal of the primary-side switch S is obtained. The modulation unit generates a modulation signal of the duty cycle value, and the driving unit 1028 generates a switching signal that can drive the primary-side switch S to switch state. The second sampling unit 1022 samples the output voltage of the second output module and calculates the difference with the second reference voltage. After processing by the processing module 1026, the frequency value of the switching signal of the primary-side switch S is obtained. The modulation unit 1027 modulates and generates a modulation signal of the frequency value, and the driving unit 1028 generates a switching signal that can drive the primary-side switch S to switch state. When the first sampling unit 1021 is used to collect the output current of the first output module and the second sampling unit is used to collect the output current of the second output module, the reference unit 1023 outputs a first reference current and a second reference current. The first reference current and the second reference current output by the reference unit 1023 can be configured as needed, and this embodiment does not limit this. The first sampling unit 1021 samples the output current of the first output module and calculates the difference with the first reference current. After processing by the processing module 1026, the duty cycle value of the switching signal of the primary-side switch S is obtained. The modulation unit generates a modulation signal of the duty cycle value, and the driving unit 1028 generates a switching signal that can drive the primary-side switch S to switch state. The second sampling unit 1022 samples the output current of the second output module and calculates the difference with the second reference current. After processing by the processing module 1026, the frequency value of the switching signal of the primary-side switch S is obtained. The modulation unit 1027 modulates the frequency value to generate a modulation signal, and the driving unit 1028 generates a switching signal that can drive the primary-side switch S to switch state. It should be noted that the primary-side switch S has only one switching signal. The processing unit 1026 constantly adjusts the frequency and duty cycle of this switching signal. That is, in this embodiment, the modulation method of the dual-output controllable flyback power supply is a hybrid modulation strategy (PWM-PFM). PWM (Pulse Width Modulation) is used to control the duty cycle of the switching signal, precisely adjusting the output voltage or current of the first output module. PFM (Pulse Frequency Modulation) is used to control the frequency of the switching signal, precisely adjusting the output voltage or current of the second output module. It should also be noted that when the dual-output controllable flyback power supply is used to adjust the output current of the first and second output modules, the first sampling unit can be set to collect the output current of the first output module, and the second sampling unit can be set to collect the output current of the second output module. The corresponding reference unit is used to generate the first and second reference currents. The functions of other modules are the same as in the above embodiment.

[0072] Optionally, continue to refer to Figure 4 The control module 102 also includes a drive protection unit 1029, which is used to detect the output voltage and output current of the input module and the modulation signal of the modulation unit, and generate a protection signal to control whether the drive unit 1028 outputs.

[0073] Specifically, in this embodiment, the drive protection unit 1029 can detect the DC voltage and DC current output by the input module in real time, which can be measured by the sensing resistor Rsense. It can also detect whether the modulation unit 1027 outputs a modulation signal in real time. When an abnormal signal is detected, the output signal of the drive unit 1028 can be directly shut down, thereby turning off the primary-side switch S. The criteria for judging abnormal signals can be set according to specific application scenarios, and this embodiment does not impose specific limitations. It should be noted that the control module 102 can be implemented by a digital integrated control IC or by a combination of separate modules.

[0074] Optionally, continue to refer to Figure 4 The input module includes: an AC power supply, such as an AC power supply of 85V to 265Vac; an input protection unit 103; an EMI filter unit 104; and a rectifier filter unit 105. The input protection unit 103 is electrically connected to the AC power supply and is used to protect the AC power supply from current and voltage. The EMI filter unit 104 is electrically connected to the input protection unit 103 and is used to filter out electromagnetic interference. The rectifier filter unit 105 is electrically connected to the EMI filter unit and is used to rectify the AC voltage into a DC voltage.

[0075] Specifically, in this embodiment, the AC power supply is converted into DC power through the input protection module 103, EMI filter module 104, and rectifier filter module 105, thereby providing a stable DC signal for the subsequent circuits. The input protection module 103 includes a fuse F1, which is used to cut off the circuit when an overcurrent occurs due to a line fault, protecting the circuit components from damage. The input protection module 103 also includes a thermistor RT, which is used to absorb the surge current at startup, preventing excessive instantaneous current from impacting the rectifier diodes and fuse, thus effectively improving the safety factor of the power supply design. The input protection module 103 also includes a varistor RV, which is used to provide a discharge path when the AC input is disconnected, preventing large current surges and also providing good clamping effect on surge voltage. The first end of the fuse F1 is electrically connected to the first end of the AC power supply, and the second end of the fuse F1 is electrically connected to the first end of the varistor RV. The first end of the thermistor RT is electrically connected to the second end of the AC power supply, and the second end of the thermistor RT is electrically connected to the second end of the varistor RV. The EMI filter module 104 can be a type of π-type filter, and may include a first capacitor CX1, an inductor L1, a second capacitor CX2, a third capacitor CY1, and a fourth capacitor CY2. The first capacitor CX1 is connected in parallel with a varistor RV. The inductor L1 includes two coils, a first coil and a second coil. The first end of the first coil is electrically connected to the first end of the first capacitor CX1, and the second end of the first coil is electrically connected to the first end of the second capacitor CX2. The first end of the second coil is electrically connected to the second end of the first capacitor CX1, and the second end of the second coil is electrically connected to the second end of the second capacitor CX2. The third capacitor CY1 and the fourth capacitor CY2 are connected in series and then connected across the two ends of the second capacitor CX2, wherein one end of the connection between the third capacitor CY1 and the fourth capacitor CY2 is grounded. The rectifier filter module 105 consists of an uncontrolled full-wave rectifier bridge (including a first diode Drec1, a second diode Drec2, a third diode Drec3, and a fourth diode Drec4) and a DC filter capacitor Cin.

[0076] This embodiment is verified through experiments. Figure 5 This is an experimental result diagram of a dual-output controllable flyback power supply provided in an embodiment of the present invention. Figure 6 The experimental results diagram for another dual-output controllable flyback power supply provided in this embodiment of the invention is shown in the figure. Figure 5 and Figure 6 In this diagram, curve L1 represents the waveform of the DC input voltage Vin, curve L2 represents the waveform of the DC output voltage Vo1 output by the first output module, curve L4 represents the waveform of the DC output voltage Vo2 output by the second output module, curve L3 represents the waveform of the DC output current Io1 output by the first output module, and curve L5 represents the waveform of the DC output current Io2 output by the second output module. Figure 5It can be seen that during DC input voltage switching, both output voltages can be maintained well at the set values ​​(Vo1 = 5V and Vo2 = 15V). Figure 6 It can be seen that the two output voltages can be maintained at the set value during load switching, which meets the set requirements. The dual-output controllable flyback power supply provided in this embodiment of the invention has the function of accurately controlling the two output voltages / currents, and the output voltage waveform is good.

[0077] This invention also provides a driving method for a dual-output controllable flyback power supply, such as... Figure 7 As shown, Figure 7 A flowchart illustrating a driving method for a dual-output controllable flyback power supply provided in an embodiment of the present invention, the driving method comprising:

[0078] Step S101: Adjust the duty cycle of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the first output module.

[0079] Step S102: Adjust the frequency of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the second output module.

[0080] Specifically, the specific operating method of the dual-output controllable flyback power supply in this embodiment can be referred to the description of the dual-output controllable flyback power supply section of this invention, and will not be repeated here. Precise control of the output voltage or output current of the first output module is achieved by adjusting the duty cycle of the primary-side switch's switching signal. Furthermore, precise control of the output voltage or output current of the second output module is achieved by adjusting the switching frequency of the primary-side switch. Through dynamic adjustment of the duty cycle and frequency of the primary-side switch's switching signal, it is possible to flexibly and precisely maintain the constant output voltage / current of both paths during changes in input voltage and / or output load, thus meeting the power requirements of downstream equipment or loads. Through functional control, precise controllability of the two power supplies can be achieved, reducing the cost and complexity of power supply design. In addition, only one primary-side switch is needed to achieve precise controllability of the two outputs, resulting in a simple structure and reduced power supply design complexity. It should be noted that the order of steps S101 and S102 is not limited; they can be executed simultaneously, with step S101 or step S102 being executed first.

[0081] Optionally, the dual-output controllable flyback power supply also includes a control module, which is used to acquire the output voltage or output current of the first output module and the second output module. The driving method further includes: the control module adjusting the duty cycle of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the first output module; and the control module adjusting the frequency of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the second output module.

[0082] Specifically, by setting a control module, the dual-output controllable flyback power supply is configured to operate in a closed-loop mode. The control module configures the first target output voltage or first target output current of the first output module and the second target output voltage or second target output current of the second output module. When the actual output voltage of the first output module deviates from the first target output voltage by more than a preset value (e.g., 1%), or the actual output current of the first output module deviates from the first target output current by more than a preset value (e.g., 1%), the duty cycle of the switching signal on the primary-side switch S can be adjusted in a timely manner to stabilize the output voltage or output current of the first output module. Similarly, when the actual output voltage of the second output module deviates from the second target output voltage by more than a preset value (e.g., 1%), or the actual output current of the second output module deviates from the second target output current by more than a preset value (e.g., 1%), the frequency of the switching signal on the primary-side switch S can be adjusted in a timely manner to stabilize the output voltage or output current of the second output module.

[0083] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A dual-output controllable flyback power supply, characterized in that, include: Input module, electromagnetic isolation module, primary-side switch, first anti-reverse current module, second anti-reverse current module, first output module, and second output module; The input module is used to provide DC voltage; the electromagnetic isolation module includes a first primary winding, a first secondary winding, a second primary winding, and a second secondary winding; the first primary winding is configured to operate in continuous current mode, and the second primary winding is configured to operate in discontinuous current mode. The first output module is coupled to the first secondary winding and is used to generate a direct current on the first output module by using the energy released by the first primary winding and the first secondary winding during the primary switch being turned off. The second output module is coupled to the second secondary winding and is used to generate a direct current on the second output module by the energy released by the second primary winding and the second secondary winding during the primary switch being turned off. The first end of the primary-side switch is connected to the first end of the input module, and the first anti-reverse current module is connected in series with the first primary-side winding and then connected between the second end of the input module and the second end of the primary-side switch; The second anti-reverse current module is connected in series with the second primary winding and then connected between the second end of the input module and the second end of the primary switch; It also includes: a control module, which is used to acquire the output voltage or output current of the first output module and adjust the duty cycle of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the first output module; The control module is also used to acquire the output voltage or output current of the second output module, and adjust the frequency of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the second output module. The first end of the first anti-reverse current module is electrically connected to the second end of the input module, the second end of the first anti-reverse current module is electrically connected to the first end of the first primary winding, and the second end of the first primary winding is electrically connected to the second end of the primary switch; the first end of the second anti-reverse current module is electrically connected to the second end of the input module, the second end of the second anti-reverse current module is electrically connected to the first end of the second primary winding, and the second end of the second primary winding is electrically connected to the second end of the primary switch; Alternatively, the first end of the first primary winding is electrically connected to the second end of the input module, the second end of the first primary winding is electrically connected to the first end of the first anti-reverse current module, and the second end of the first anti-reverse current module is electrically connected to the second end of the primary switch; the first end of the second primary winding is electrically connected to the second end of the input module, the second end of the second primary winding is electrically connected to the first end of the second anti-reverse current module, and the second end of the second anti-reverse current module is electrically connected to the second end of the primary switch.

2. The dual-output controllable flyback power supply according to claim 1, characterized in that, Also includes: A clamping module is connected between the second end of the input module and the second end of the primary-side switch. It is used to absorb and dissipate the energy of the leakage inductance of the first primary-side winding and the energy of the leakage inductance of the second primary-side winding.

3. The dual-output controllable flyback power supply according to claim 2, characterized in that, The clamping module includes a first clamping capacitor, a first clamping resistor, and a clamping diode; a first terminal of the first clamping capacitor is electrically connected to a second terminal of the input module, a second terminal of the first clamping capacitor is electrically connected to the cathode of the clamping diode, the first clamping resistor is connected in parallel with the first clamping capacitor, and the anode of the clamping diode is electrically connected to a second terminal of the primary-side switch. Alternatively, the clamping module includes a second clamping capacitor, a second clamping resistor, and a clamping transistor. The first terminal of the second clamping capacitor is electrically connected to the second terminal of the input module, the second terminal of the second clamping capacitor is electrically connected to the first terminal of the clamping transistor, the second clamping resistor is connected in parallel with the second clamping capacitor, and the second terminal of the clamping transistor is electrically connected to the second terminal of the primary-side switch.

4. The dual-output controllable flyback power supply according to claim 1, characterized in that, The control module includes: The first sampling unit is electrically connected to the first output module and is used to collect the output voltage or output current of the first output module. The second sampling unit is electrically connected to the second output module and is used to collect the output voltage or output current of the second output module. A reference unit is used to generate a first reference voltage and a second reference voltage, or to generate a first reference current and a second reference current. A first arithmetic unit, wherein a first input terminal of the first arithmetic unit is electrically connected to the first sampling unit, and a second input terminal of the first arithmetic unit is electrically connected to the first reference output terminal of the reference unit, is used to perform a first preset arithmetic operation; The second arithmetic unit has a first input terminal electrically connected to the second sampling unit and a second input terminal electrically connected to the second voltage output terminal of the reference unit, and is used to perform a second preset arithmetic operation. A processing unit, configured to generate control signals based on the calculation results of the first arithmetic unit and the second arithmetic unit; A modulation unit, wherein the modulation unit is used to adjust the duty cycle and frequency of the output modulation signal according to the control signal; A driving unit is used to control the switching state of the primary-side switch according to the modulation signal.

5. The dual-output controllable flyback power supply according to claim 4, characterized in that, The control module also includes: A drive protection unit is provided, which is used to detect the output voltage and output current of the input module and the modulation signal of the modulation unit, and generate a protection signal to control whether the drive unit outputs.

6. The dual-output controllable flyback power supply according to claim 1, characterized in that, The input module includes: an AC power supply, an input protection unit, an EMI filter unit, and a rectifier filter unit; The input protection unit is electrically connected to the AC power supply and is used to provide current and voltage protection for the AC power supply. The EMI filtering unit is electrically connected to the input protection unit and is used to filter out electromagnetic interference; The rectifier filter unit is electrically connected to the EMI filter unit and is used to rectify AC voltage into DC voltage.

7. The dual-output controllable flyback power supply according to claim 1, characterized in that, The primary-side switch is any one of a transistor, a metal-oxide-semiconductor field-effect transistor, a silicon carbide transistor, a gallium nitride transistor, a high electron mobility transistor, and an insulated-gate bipolar transistor.

8. The dual-output controllable flyback power supply according to claim 1, characterized in that, The first primary winding, the first secondary winding, the second primary winding, and the second secondary winding are integrated on the same transformer.

9. A driving method for a dual-output controllable flyback power supply, characterized in that, The dual-output controllable flyback power supply is the dual-output controllable flyback power supply according to any one of claims 1-7, and the driving method includes: The duty cycle of the signal at the control terminal of the primary-side switch is adjusted according to the output voltage or output current of the first output module. The frequency of the signal at the control terminal of the primary-side switch is adjusted according to the output voltage or output current of the second output module.

10. The driving method for a dual-output controllable flyback power supply according to claim 9, characterized in that, The dual-output controllable flyback power supply also includes a control module, which is used to acquire the output voltage or output current of the first output module and the second output module. The driving method further includes: The control module adjusts the duty cycle of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the first output module. The control module also adjusts the frequency of the signal at the control terminal of the primary-side switch according to the output voltage or output current of the second output module.

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