CN115589155A - Control circuit, power module and electronic equipment of asymmetric half-bridge flyback circuit - Google Patents
Control circuit, power module and electronic equipment of asymmetric half-bridge flyback circuit Download PDFInfo
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- CN115589155A CN115589155A CN202211216338.1A CN202211216338A CN115589155A CN 115589155 A CN115589155 A CN 115589155A CN 202211216338 A CN202211216338 A CN 202211216338A CN 115589155 A CN115589155 A CN 115589155A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33571—Half-bridge at primary side of an isolation transformer
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The application provides a control circuit, power module and electronic equipment of asymmetric half-bridge flyback circuit. The control circuit is used for outputting a control signal to control the main power tube and the auxiliary power tube. And in response to the input voltage falling to be smaller than the first voltage threshold, the auxiliary power tube is alternately turned off and turned on according to a first preset turn-off duration and a second preset turn-on duration. And responding to the rising of the input voltage to be larger than a second voltage threshold value, and the main power tube and the auxiliary power tube are alternately switched on and off. The resonance capacitor and the resonance inductor of the asymmetric half-bridge flyback circuit form a resonance circuit, and the ratio of the second preset conduction time to the time of the resonance period of the resonance circuit is less than or equal to 0.25. The application can ensure the stable operation of the control circuit, the power module and the electronic equipment of the asymmetric half-bridge flyback circuit, and the service life is prolonged.
Description
Technical Field
The application relates to the technical field of electronic power, in particular to a control circuit of an asymmetric half-bridge flyback circuit, a power module and electronic equipment.
Background
The power supply module generally includes a dc conversion circuit and a control circuit. The control circuit is used for outputting a control signal to control the direct current conversion circuit. Taking the dc conversion circuit as an asymmetric half-bridge flyback circuit as an example, the asymmetric half-bridge flyback circuit includes a half-bridge circuit, a transformer, a resonant capacitor and an output capacitor. The half-bridge circuit comprises a main power tube and an auxiliary power tube. When the input voltage of the asymmetric half-bridge flyback circuit is in a low phase, the control circuit needs to control the asymmetric half-bridge flyback circuit to stop working.
Typically, the voltage of the output capacitor is V before the input voltage enters the low phase o And the voltage of the resonant capacitor is multiplied by V o . The voltage of the resonant capacitor may be maintained at N x V after the input voltage enters the low phase o As the output load continues to pull down the voltage of the output capacitor of the asymmetric half-bridge flyback circuit, the voltage of the output capacitor will become V when exiting the low phase o_ini ,V o_ini Much less than V o Therefore, the voltage of the output capacitor is not matched with the voltage of the resonant capacitor, when the asymmetric half-bridge flyback circuit recovers to work, the control circuit controls the auxiliary power tube to be conducted, the resonant capacitor discharges to generate overshoot current, the auxiliary power tube and the rectifying circuit generate great current impact, and the service life of a device is influenced or even the device can be directly damaged.
Disclosure of Invention
In view of this, the application provides a control circuit, power module and electronic equipment of asymmetric half-bridge flyback circuit, can avoid output capacitor voltage and unmatched and overcurrent problem that leads to of resonance capacitor voltage, guarantees power module and electronic equipment's stability, promotes the competitiveness of product.
A first aspect of the application provides a power module including an asymmetric half-bridge flyback circuit for receiving an input voltage and providing an output voltage, and a control circuit. The asymmetric half-bridge flyback circuit comprises a transformer, a resonant capacitor, a main power tube and an auxiliary power tube, wherein the control circuit is used for outputting a control signal to control the main power tube and the auxiliary power tube. And in response to the input voltage falling to be smaller than the first voltage threshold, the auxiliary power tube is alternately turned off and turned on according to the first preset turn-off duration and the second preset turn-on duration. And in response to the input voltage rising to be larger than a second voltage threshold value, the main power tube and the auxiliary power tube are switched on and off alternately. Wherein the ratio of the second preset conduction time duration to the time duration of the resonant period of the asymmetric half-bridge flyback circuit is less than or equal to 0.25.
This application through control circuit to the main power tube with the control that auxiliary power tube goes on can avoid output capacitor voltage and the unmatched overcurrent problem that leads to of resonance capacitor voltage, the current stress that produces on auxiliary power tube, transformer when having reduced resonance capacitor discharge's electric current discharge, guarantees the steady operation of power module, can improve the life of power module.
As an optional implementation, the main power tube is used for: responsive to the input voltage falling below a first voltage threshold, remain off in accordance with the control signal. Based on such design, can promote the efficiency of power module.
As an alternative implementation manner, the transformer includes a primary winding and a secondary winding, the source of the main power tube is connected to the drain of the auxiliary power tube and a first end of the primary winding, the source of the auxiliary power tube is connected to the reference ground and one end of the resonant capacitor, and the other end of the resonant capacitor is connected to a second end of the primary winding, where: and when the auxiliary power tube is switched on, the resonance capacitor discharges, and when the auxiliary power tube is switched off, the resonance capacitor stops discharging. Therefore, current stress generated on the auxiliary power tube and the transformer during current discharge of the resonant capacitor can be reduced, and the stability of the power module is improved.
As an optional implementation manner, the power supply module includes an auxiliary winding circuit, the auxiliary winding circuit includes an auxiliary winding, the auxiliary winding circuit is used for supplying power to the control circuit, and the auxiliary winding is coupled to the primary winding.
The second aspect of the present application further provides a control circuit of an asymmetric half-bridge flyback circuit, where the asymmetric half-bridge flyback circuit includes a transformer, a resonant capacitor, a main power transistor and an auxiliary power transistor, and the control circuit is configured to: obtaining a comparison result of a voltage value of an input voltage of the asymmetric half-bridge flyback circuit and a first voltage threshold or a second voltage threshold; when the voltage value of the input voltage is reduced to be smaller than a first voltage threshold value, controlling the auxiliary power tube to be alternately turned off and turned on according to a first preset turn-off duration and a second preset turn-on duration; when the voltage value of the input voltage rises to be larger than a second voltage threshold value, controlling the main power tube and the auxiliary power tube to be alternately switched on and off; and the ratio of the second preset time length to the time length of the resonance period of the asymmetric half-bridge flyback circuit is less than or equal to 0.25. This application can be through control circuit to the main power tube with the auxiliary power tube is controlled, can avoid output capacitor voltage to mismatch and the overcurrent problem that leads to with resonance capacitor voltage like this, the current stress that produces on auxiliary power tube, transformer when having reduced resonance capacitor discharge's electric current discharges guarantees the steady operation of power module, can improve the life of power module.
As an optional implementation, the control circuit is further configured to: and controlling the main power tube to be kept off in response to the input voltage being smaller than the first voltage threshold value, so that the efficiency of the power module can be improved.
As an optional implementation manner, the control circuit is configured to obtain the second preset on-duration according to a resonance period of the resonance circuit, or the control circuit is configured to obtain the second preset on-duration according to the resonance capacitor and the resonance inductor.
As an alternative implementation, the control circuit is further configured to: in response to the situation that the input voltage drops to be smaller than the first voltage threshold and the input voltage rises to be larger than the second voltage threshold, obtaining a difference value of the voltage of the resonant capacitor before the auxiliary power tube is turned on in two consecutive first periods, wherein the duration of the first period is the sum of a first preset turn-off duration and a second preset turn-on duration; in response to the fact that the difference value of the voltages of the resonance capacitors before the auxiliary power tube is conducted in two consecutive first periods does not increase and the input voltage rises to be larger than the second voltage threshold value, controlling the main power tube to be conducted for a first time length in each second period; in response to the difference value of the voltages of the resonance capacitors before the auxiliary power tube is conducted in two consecutive first periods being increased and the input voltage rising to be larger than the second voltage threshold, controlling the main power tube to be conducted for a second time length in each second period; wherein the second duration is greater than the first duration. By adopting the design, after the power supply module exits the intermittent mode and enters the normal working mode, the current peak value of the main power tube can be increased by increasing the conduction time of the main power tube in a plurality of periods.
As an alternative implementation, the control circuit is further configured to: responding to the situation that the input voltage is decreased to be smaller than the first voltage threshold and the situation that the input voltage is increased to be larger than the second voltage threshold, and acquiring a difference value of the voltage of the resonant capacitor before the auxiliary power tube is conducted in two continuous first periods, wherein the duration of the first period is the sum of a first preset turn-off duration and a second preset turn-on duration; in response to that the difference value of the voltages of the resonance capacitors before the auxiliary power tube is conducted in two consecutive first periods is smaller than a third voltage threshold and the input voltage rises to be larger than the second voltage threshold, controlling the main power tube to be conducted for a first time length in each second period; in response to that the difference value of the voltages of the resonance capacitors before the auxiliary power tube is conducted in two consecutive first periods is larger than a third voltage threshold and the input voltage rises to be larger than the second voltage threshold, controlling the main power tube to be conducted for a second time length in each second period; wherein the second duration is greater than the first duration. Such a design helps the control circuit to determine whether the power module is heavily loaded during the intermittent state. By adopting the design, after the power supply module exits the intermittent mode and enters the normal working mode, the current peak value of the main power tube can be increased by increasing the conduction time of the main power tube in a plurality of periods.
The third aspect of the present application further provides an electronic device including the power module as described above, or a control circuit including the asymmetric half-bridge flyback circuit as described above.
The application discloses control circuit, power module and electronic equipment of asymmetric half-bridge flyback circuit when input voltage gets into the low phase place, through the state of auxiliary power pipe in the asymmetric half-bridge flyback circuit of control circuit control, can avoid output capacitor voltage and the unmatched overcurrent problem that leads to of resonance capacitor voltage, promote power module's safety and stability, promote the competitiveness of product.
Drawings
Fig. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present disclosure.
Fig. 2 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Fig. 3 is a schematic structural diagram of a power module according to an embodiment of the present disclosure.
Fig. 4 is a schematic circuit diagram of a power module according to an embodiment of the present disclosure.
Fig. 5 is a simplified circuit diagram of the power module.
Fig. 6 is a schematic diagram of an equivalent circuit after the auxiliary power transistor in the power module is turned on.
Fig. 7 is a schematic diagram of a control logic of the control circuit provided in the present application.
Fig. 8 is a schematic flowchart of a control circuit provided in the present application for controlling an asymmetric half-bridge flyback circuit.
Fig. 9 is another schematic flow chart of the control circuit provided in the present application for controlling the asymmetric half-bridge flyback circuit.
Detailed Description
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. When an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an electronic device 100 according to an embodiment of the present disclosure.
As shown in fig. 1, the electronic device 100 may include a power module 10 and a load 20. The power module 10 is used for receiving an input voltage V in And providing an output voltage V out To supply the load 20. In one embodiment, the input voltage V in May be provided by an external power source or may also be provided by an internal power source of the electronic device 100. It is to be understood that the electronic device 100 provided in the embodiment shown in fig. 1 may be an electric device such as a mobile phone, a notebook computer, a computer case, an electric vehicle, a smart speaker, a smart watch, or a wearable device. The power module 10 can be applied to the electronic device 100 shown in fig. 1.
Referring to fig. 2, fig. 2 is a schematic view illustrating another structure of an electronic device 100 according to an embodiment of the present disclosure. As shown in fig. 2, the electronic device 100 may include a power module 10. The power module 10 may be configured to receive an input voltage V in And providing an output voltage V out And supplying power to a load subsequently connected to the electronic device 100. In one embodiment, the input voltage V in May be provided by an external power source or may also be provided by an internal power source of the electronic device 100.
As shown in fig. 2, the electronic device 100 provided in this embodiment may be a power supply device such as a power adapter, a charger, and a mobile power supply. The power module 10 provided in the embodiment of the present application can be applied to the electronic device 100 shown in fig. 2.
In an embodiment of the present application, the electronic device 100 may further include a plurality of power modules 10, and the plurality of power modules 10 provide the output voltage V out To power the load 20. In an embodiment of the present application, the electronic device 100 may include a plurality of loads 20, and the power module 10 may provide a plurality of output voltages V out A plurality of loads 20 are supplied with power, respectively. In an embodiment of the present application, the electronic device 100 may include a plurality of power modules 10 and a plurality of loads 20, and the plurality of power modules 10 may respectively provide a plurality of output voltages V out To power a plurality of loads 20.
In one embodiment of the present application, the input voltage V in May be an alternating current, and the power module 10 may include an ac-dc conversion circuit. In the embodiment of the present application, the input voltage V in Which may be a dc power, the internal power source may include an energy storage device, and the power module 10 may include a dc conversion circuit. Accordingly, when the electronic device 100 operates independently, the energy storage device of the internal power supply can supply power to the power module 10.
In one embodiment of the present application, the input voltage V in May be a direct current. The load 20 of the electronic device 100 may include one or more of a power consumption device, an energy storage device, or an external device. In one embodiment, the load 20 may be a power consuming device of the electronic apparatus 100, such as a processor, a display, and the like. In one embodiment, the load 20 may be an energy storage device of the electronic apparatus 100, such as a battery. In one embodiment, the load 20 may be an external device of the electronic device 100, such as a display, a keyboard, and other electronic devices.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a power module according to an embodiment of the present disclosure. As shown in fig. 3, the power module 10 includes a control circuit 11, a dc converter circuit 12, an auxiliary winding circuit 13, and a rectifier circuit 14. The power module 10 is used for receiving an input voltage V provided by an input power source in And providing an output voltage V out To power the load 20.
The control circuit 11 is connected to the dc conversion circuit 12. The control circuit 11 may be used to control the operation of the dc conversion circuit 12. In one embodiment, the control circuit 11 may be configured to output a control signal, and the control signal may be configured to control the dc conversion circuit 12. For example, the input terminal of the DC conversion circuit 12 is used for receiving an input voltage V in The control circuit 11 controls the dc conversion circuit 12 to input voltage V in Processed to provide an output voltage V 1 . In the embodiment of the present application, the input voltage V in Is direct current.
The rectifying circuit 14 may be used for providing an output voltage V to the dc conversion circuit 12 1 After rectification and the like, an output voltage V is provided out 。
The auxiliary winding circuit 13 may be configured to receive power from the transformer in the dc conversion circuit 12 and supply power to the control circuit 11. In the embodiment of the present application, the auxiliary winding circuit 13 may include a voltage stabilizing circuit or the like.
Referring to fig. 4, fig. 4 is a schematic circuit structure diagram of a power module according to an embodiment of the present disclosure. As shown in fig. 4, the power module 10 includes a dc conversion circuit 12, a rectifier circuit 14, an auxiliary winding circuit 13, and a control circuit 11.
The dc conversion circuit 12 in the power module 10 is an asymmetric Half-Bridge (AHB) flyback circuit 12a as an example. The asymmetric half-bridge flyback circuit 12a may include a half-bridge circuit 121, a transformer 122, and a resonant capacitor Cr.
Wherein the half-bridge circuit 121 may include a main power transistor Q L And an auxiliary power tube Q H . The main power tube Q L And the auxiliary power tube Q H An asymmetric half-bridge topology can be formed. In one embodiment, the control circuit 11 may provide the main power transistor Q with power signals L And an auxiliary power tube Q H Sending a control signal to make the main power tube Q L And the auxiliary power tube Q H May be turned on in response to a received control signal. The masterPower tube Q L Receives an input voltage V at the drain in The main power tube Q L Source electrode of and the auxiliary power tube Q H Is connected with the drain electrode of the auxiliary power tube Q H Is connected to a reference ground. The main power tube Q L May be configured to receive a first control signal sent by the control circuit 11, and may be turned on according to the first control signal. The auxiliary power tube Q H May be configured to receive a second control signal of the control circuit 11 and may be turned on in accordance with the second control signal.
In the embodiment of the present application, the main power Transistor and the auxiliary power Transistor may be Metal-Oxide-Semiconductor Field-Effect transistors (MOSFETs), insulated Gate Bipolar Transistors (IGBTs), bipolar power transistors (Bipolar power transistors), wide bandgap MOSFETs, or the like.
In the embodiment of the present application, the main power transistor and the auxiliary power transistor may be different types of transistors respectively. Illustratively, the main power tube is a MOSFET and the auxiliary power tube is an IGBT. Alternatively, the main power transistor and the auxiliary power transistor may be the same type of transistor. Illustratively, the main power tube and the auxiliary power tube are both MOSFETs. It should be understood that, in the embodiment of the present application, only the main power transistor and the auxiliary power transistor are taken as MOSFETs for example, but the embodiment of the present application does not limit the types of transistors of the main power transistor and the auxiliary power transistor.
In the embodiment of the application, the driving modes of the main power tube and the auxiliary power tube are high-level conduction and low-level shutdown. Illustratively, the main power transistor receives a high level driving signal, and the main power transistor is turned on. The main power tube receives the low level driving signal, and the main power tube is switched off. It can be understood that other driving manners may also be adopted for the main power tube and the auxiliary power tube in the embodiment of the present application, and the driving manners of the main power tube and the auxiliary power tube are not limited in the embodiment of the present application.
The control circuit 11 provided in the embodiment of the present application may include a Pulse-width modulation (PWM) controller, a Central Processing Unit (CPU), other general processors, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic devices, a discrete gate or a transistor logic device, and the like.
The half-bridge circuit 121 may be configured to receive the input voltage V in And provides an output voltage to the primary winding 1221 of the transformer 122 through the resonant capacitor Cr according to the control signal provided by the control circuit 11. The transformer 122 includes a primary winding 1221, a secondary winding 1222, and a magnetic core 1223. The secondary winding 1222 of the transformer 122 is coupled to the primary winding 1221 via a magnetic core 1223, and the auxiliary winding 131 is coupled to the primary winding 1221 of the transformer 122 via a magnetic core 1223. The primary winding 1221 of the transformer 122 is used for receiving the output voltage of the half-bridge circuit 121 and generating a primary winding voltage. The secondary winding 1222 of the transformer 122 is coupled to the primary winding 1221, and a secondary winding voltage can be generated on the secondary winding 1222. The rectifying circuit 14 can be used to receive the secondary winding voltage on the secondary winding 1222 and convert the secondary winding voltage into an output voltage V out 。
It is understood that the primary winding can be referred to as being placed on the primary side of the transformer, corresponding to the input voltage V in Of the current of (2). The secondary winding can be placed on the secondary side of the transformer and corresponds to the output voltage V 1 Of the current of (2). The auxiliary winding circuit 13 may include an auxiliary winding coupled with the transformer.
As shown in fig. 4, one end of the resonant capacitor Cr may be connected to the auxiliary power transistor Q H The other end of the resonant capacitor Cr is connected to the first end of the primary winding 1221 and the resonant inductor L m A second end of the primary winding 1221 is connected to the main power tube Q via a resonant inductor Lr L Source electrode of and the auxiliary power tube Q H Of the substrate. The resonance inductor L m Second end of the primary winding is connected with the primary winding1221, and a second end of the same. An output voltage V provided by a secondary winding 1222 of the transformer 122 1 And provides an output voltage V after being processed by the rectifying circuit 14 out 。
In one embodiment, the rectifying circuit 14 may include a diode D 1 And an output capacitor C 1 . The diode D 1 Is connected to a first end of the secondary winding 1222. The output capacitor C 1 Are respectively connected with the diode D 1 And a second end of the secondary winding 1222.
The half-bridge circuit 121 may include a diode D 2 Diode D 3 Capacitor C 2 And a capacitor C 3 . The diode D 2 Cathode of (2) is connected to the capacitor C 2 And the main power tube Q L The diode D 2 Anode of (2) is connected to the capacitor C 2 And the main power tube Q L Of the substrate. The diode D 3 Cathode of (2) is connected to the capacitor C 3 And the auxiliary power tube Q H The diode D 3 Anode of (2) is connected with the capacitor C 3 And the auxiliary power tube Q H Of the semiconductor device.
The auxiliary winding circuit 13 may include an auxiliary winding 131. The auxiliary winding 131 can be coupled to the primary winding 1221 through the magnetic core 1223. The primary winding voltage on the primary winding 1221 is coupled to generate an auxiliary winding voltage on the auxiliary winding 131. The auxiliary winding circuit 13 may supply power to the control circuit 11 according to an auxiliary winding voltage. The auxiliary winding circuit 13 may include a BOOST (BOOST) circuit, a BUCK (BUCK) circuit, a BUCK-BOOST (BUCK-BOOST) circuit, and the like. In an embodiment, the auxiliary winding circuit 13 may also be a low dropout regulator (LDO) or other regulator.
In one embodiment, the control circuit 11 may send a control signal to control the main power transistor Q in the half-bridge circuit 121 of the asymmetric half-bridge flyback circuit 12a L And an auxiliary power tube Q H Thereby controlling the operation state of the asymmetric half-bridge flyback circuit 12 a. For example, the control circuit 11 adjusts the frequency or duty ratio of the control signal to control the main power transistor Q in the half-bridge circuit 121 L And an auxiliary power tube Q H So as to adjust the voltage value of the output voltage of the half-bridge circuit 121 accordingly, and further adjust the output voltage V of the asymmetric half-bridge flyback circuit 12a 1 And controls the output voltage V of the power module 10 out The voltage value of (2). In one embodiment, the control circuit 11 can send a control signal to control the main power transistor Q in the half-bridge circuit 121 L And an auxiliary power tube Q H On and off.
For example, the control circuit 11 may control the main power transistor Q by supplying power to the main power transistor Q L Controlling the main power tube Q in a manner of sending a first control signal L On or off, and by applying voltage to said auxiliary power transistor Q H Controlling auxiliary power tube Q by sending second control signal H On or off. In the embodiment of the present application, the first control signal and the second control signal may include a high level signal or a low level signal. In one embodiment, the main power tube Q L Can be conducted according to a first control signal, and the auxiliary power tube Q H May be turned on according to the second control signal. In one embodiment, the main power tube Q L Can be switched off according to a first control signal, and the auxiliary power tube Q H May be turned off in accordance with the second control signal, etc.
Fig. 5 is a simplified circuit diagram of a power module. According to the power module 10 shown in fig. 4, a simplified circuit as shown in fig. 5 can be obtained. The primary winding 1221 of the transformer 122 in the asymmetric half-bridge flyback circuit 12a may provide the resonant inductance Lr. For example, the resonant inductance Lr may be parasitic on the primary winding 1221 of the transformer 122. The main power tube Q of the asymmetric half-bridge flyback circuit 12a L And an auxiliary power tube Q H Alternately switched on and off. The output voltage V of the power module 10 out Stabilized at a rated output voltageThe voltage value of the constant output voltage is recorded as V o . Meanwhile, according to the simplified circuit, about equation V can be obtained cr ≈N*V out Wherein V is cr N is the turn ratio of the primary winding 1221 and the secondary winding 1222 of the transformer 122, which is the voltage across the resonant capacitor Cr.
Although in the main power tube Q of the asymmetric half-bridge flyback circuit 12a L And an auxiliary power tube Q H When alternately conducting, the voltage at the two sides of the resonant capacitor Cr and the output voltage V of the power module 11 out There is a relationship expressed by the above approximate expression. However, in some cases, the voltage across the resonant capacitor Cr may be much higher than N × V out The above approximate equation cannot be satisfied. For example, when the control circuit 11 periodically switches the main power transistor Q to the asymmetric half-bridge flyback circuit 12a L And an auxiliary power tube Q H Main power tube Q for transmitting control signal and controlling L And an auxiliary power tube Q H Alternately switched on and off. At this time, the output voltage V of the power module 10 out And stabilizing at the rated voltage. Then, if the input voltage V is in When the phase is low, the control circuit 11 needs to control the asymmetric half-bridge flyback circuit 12a to stop working, i.e. the main power tube Q of the asymmetric half-bridge flyback circuit 12a is obtained L And an auxiliary power tube Q H An off operating state. At this time, the voltage across the resonant capacitor Cr may be maintained at N × V out As the output load continuously pulls down the voltage of the output capacitor of the asymmetric half-bridge flyback circuit, the voltage across the capacitor C1 will become V o_ini In which V is o_ini Will be much less than V out 。
At the input voltage V in When entering the high phase, the control circuit 11 may then control the asymmetric half-bridge flyback circuit 12a to switch from the main power transistor Q L And an auxiliary power tube Q H The working state of all the switches is switched off to be the working state again. The control circuit 11 is connected to the main power tube Q in the asymmetric half-bridge flyback circuit 12a L And an auxiliary power tube Q H Sending a control signal to make the main power tube Q L And the auxiliary power tube Q H Alternately turned on and off according to the control signal.
Fig. 6 is a schematic diagram of an equivalent circuit after the auxiliary power tube in the power module is turned on. It can be seen that the auxiliary power transistor Q in the power module 10 H After the conduction, the voltage V at the two sides of the resonance capacitor Cr cr May be much larger than the output voltage V of the output terminal of the power module 10 out * And N is added. Therefore, the current generated by the resonant capacitor Cr will be directly transmitted to the secondary rectifier circuit 14 through the transformer 122. Therefore, when the auxiliary power tube Q H After the power supply is switched on, the resonant capacitor Cr generates an overshoot current, and the overshoot current is generated in the auxiliary power tube Q H The transformer 122 and the rectifier circuit 14 generate a great current stress.
The application provides a control circuit, power module and electronic equipment of asymmetric half-bridge flyback circuit, can be used to overcome above-mentioned problem. The technical solution of the present application will be described in detail below with specific examples. These several specific embodiments may be combined with each other below, and details of the same or similar concepts or processes may not be repeated in some embodiments.
Fig. 7 is a schematic control logic diagram of a control circuit according to an embodiment of the present disclosure.
The control circuit 11 can be applied to the power module 10 shown in fig. 4. The control circuit 11 provided by the present application can be used to control an asymmetric half-bridge flyback circuit 12a as shown in fig. 4. In the example shown in fig. 7, the dc converter circuit 12 is an asymmetric half-bridge flyback circuit 12a in fig. 4 as an example. It is understood that the control logic provided by the control circuit 11 in the present application can also be applied to the control of the control circuit 11 for controlling the other types of dc conversion circuits 12.
When the auxiliary power transistor Q is combined with the circuit structure diagram shown in FIG. 4 H When the capacitor is conducted, the resonant capacitor Cr can pass through the primary winding 1221, the resonant inductor Lr and the auxiliary power tube Q H And (4) discharging. When the auxiliary power tube Q H When the switch is turned off, the resonance capacitor Cr stops discharging.
It will be appreciated that the control circuit 11An input voltage V to the asymmetric half-bridge flyback circuit 12a in And (6) detecting. If the control circuit 11 obtains the input voltage V in Falls to less than or equal to a first voltage value V in1 I.e. the asymmetric half-bridge flyback circuit 12a has entered into the discontinuous mode, the control circuit 11 will execute the control logic shown in fig. 7. For example, the control circuit 11 may control the auxiliary power transistor Q H Periodically alternating off and on. Wherein the auxiliary power tube Q H And setting the time length of each turn-off of the first control signal of the control circuit 11 as a first preset turn-off time length T1. The auxiliary power tube Q H And setting the time length of each conduction of the second control signal of the control circuit 11 as a second preset conduction time length T2. In other words, at said input voltage V in Falls below a first voltage threshold V in1 While the auxiliary power tube Q H The switching-off and the switching-on can be alternately performed according to a first preset switching-off duration T1 and a second preset switching-on duration T2.
As shown in fig. 7, when the control circuit 11 acquires the input voltage V in Falls to less than or equal to a first voltage value V in1 Then, the control circuit 11 outputs a first control signal to the auxiliary power transistor Q H To control the auxiliary power tube Q H The first preset time period T1 is turned off.
As shown in fig. 7, the auxiliary power tube Q H After the first preset turn-off duration T1 is turned off according to the first control signal, at this time, the voltage V at two sides of the resonant capacitor Cr cr Has been greater than the reflected voltage N x V of the output capacitor C1 out . The control circuit 11 outputs a second control signal to the auxiliary power transistor Q H To control the auxiliary power tube Q H And conducting for a second preset conducting time period T2.
It is understood that the second preset on-time T2 is less than a predetermined value. The predetermined value may be 25% of the resonance period of the resonant circuit in the half bridge circuit 121. For example, the second preset on-time T2 may be 10% -15% of the resonance period, etc. The resonance time when the resonance circuit generates zero input corresponding resonance is lowVoltage V on both sides of the resonance capacitor Cr at 25% of the resonance period cr Is not greater than the reflection voltage N x V of the output capacitor C1 out And a voltage variation quantity DeltaV of the resonance capacitor Cr Cr Is proportional to the auxiliary power tube Q H Before the conduction, the voltage V at two sides of the resonance capacitor Cr cr And N x V out This effectively limits the resonance duration and reduces the overshoot current of the resonant circuit.
In the auxiliary power tube Q H In the process of periodically and alternately turning off and turning on, the resonance capacitor Cr periodically and alternately stops discharging and discharges, so that the charge in the resonance capacitor Cr can be gradually released. The voltage value V of the resonance capacitor Cr shown in FIG. 7 cr On the waveform diagram, the voltage on the two sides of the resonance capacitor Cr shows a step-like descending rule.
It can be understood that, in this embodiment, the first preset turn-off duration T1 and the second preset turn-on duration T2 may be preset fixed values, or may be calculated by a control circuit. For example, the first preset off-period T1 and the second preset on-period T2 may be fixed values set in advance.
In an embodiment, the control circuit 11 may obtain the circuit parameters of the asymmetric half-bridge flyback converter 12a through a Universal Asynchronous Receiver/Transmitter (UART) interface or the like. The circuit parameters may include a capacitance value of the resonant capacitor Cr, an inductance value of the resonant inductor Lr, a frequency fpre of the control circuit 11 sending the control signal, and a preset number of times 20 that the auxiliary power tube QH is turned on. The circuit parameters acquired by the control circuit 11 may be configured by an engineer. The control circuit 11 may calculate a first preset turn-off duration T1 and a second preset turn-on duration T2 according to these circuit parameters. In some embodiments, the second preset on-time T2 may be 10% to 15% of a length of a resonant period formed by the resonant capacitor Cr and the resonant inductor Lr, for example, the second preset on-time T2 is 300ns. It is understood that, in order to balance the voltage difference before each discharge with the number of discharges, the first preset turn-off time period T1 may be set to 250us.
At the time 0-t1, the control circuit 11 controls the auxiliary power tube Q H And turning off to stop discharging the resonant capacitor Cr. The voltage V at two sides of the resonance capacitor Cr cr May remain unchanged from time 0-t 1. At time t1 to time t2, the control circuit 11 controls the auxiliary power tube Q H Conducting to discharge the resonance capacitor Cr, and the voltage V at two sides of the resonance capacitor Cr cr The decrease is started. At the moment t2, the voltage V on the two sides of the resonance capacitor Cr cr And N x V out The difference is smaller than the predetermined value. Wherein, the preset value can be set to be smaller. At the moment t2, the voltage V on the two sides of the resonance capacitor Cr cr Close to and slightly greater than N x V out So that about the equation Vcr ≈ N × V out This is true.
At time t2 to time t3, the control circuit 11 controls the auxiliary power tube Q H And turning off to stop discharging the resonant capacitor Cr. At time t3 to time t4, the control circuit 11 controls the auxiliary power tube Q H Conducting to discharge the resonance capacitor Cr, and the voltage V at two sides of the resonance capacitor Cr cr And (4) reducing. At the moment t4, the voltage V on the two sides of the resonant capacitor Cr cr And N x V out The difference is smaller than the predetermined value. At the moment t4, the voltage V on the two sides of the resonant capacitor Cr cr Close to and slightly greater than N x V out So that about the equation Vcr ≈ N × V out This is true.
The control circuit 11 controls the auxiliary power tube Q H Periodically alternately switching off and on until the input voltage V is detected in Rises to a second voltage value V or higher in2 When the voltage is over, the control circuit 11 will control the main power tube Q L And an auxiliary power tube Q H Alternately switched on and off. At this time, the asymmetric half-bridge flyback circuit 12a exits the burst mode, and the asymmetric half-bridge flyback circuit 12a may operate in a normal operating state and may output a rated voltage according to the input voltage. In the main power tube Q L And the auxiliary power tube Q H When the switch-on and the switch-off are alternately conducted,the voltage V at the two sides of the resonance capacitor Cr cr Close to and slightly greater than N x V out So that the current discharged by the resonant capacitor Cr will not flow in the auxiliary power tube Q H The transformer 122 and the rectifier circuit 14 generate a great current stress.
To sum up, the control circuit 11 provided in the embodiment of the present application controls the asymmetric half-bridge flyback circuit 12a, so as to reduce the current discharged by the resonant capacitor Cr and discharge at the auxiliary power transistor Q H The current stress generated by the transformer 122 and the rectifying circuit 14 ensures the stable operation of the asymmetric half-bridge flyback circuit 12a, the power module 10 and the electronic device 100 in which the power module 10 is located, and prolongs the service life of the asymmetric half-bridge flyback circuit 12a, the power module 10 and the electronic device 100.
Fig. 8 is a schematic flowchart illustrating a control circuit controlling an asymmetric half-bridge flyback circuit according to an embodiment of the present application.
In S81, the asymmetric half-bridge flyback circuit 12a is controlled to operate in a normal operation state.
Taking the power module 10 shown in fig. 4 as an example for illustration, the control circuit 11 can control the asymmetric half-bridge flyback circuit 12a to operate in a normal operating state, i.e. the control circuit 11 controls the main power transistor Q L And the auxiliary power tube Q H Alternately switched on and off.
In S82, it is acquired whether the input voltage falls to less than or equal to the first voltage value. If the input voltage drops to less than or equal to the first voltage value, S83 is executed, otherwise S82 is returned to.
It will be appreciated that the control circuit 11 may obtain the input voltage V in The size of (2). When the control circuit 11 obtains the input voltage V in Falls to less than or equal to a first voltage value V in1 And controlling the asymmetric half-bridge flyback circuit 12a to enter an intermittent state.
In S83, the auxiliary power tube is controlled to be turned off for a first preset turn-off time period T1.
When the input voltage V in Falls to less than or equal to a first voltage value V in1 When it is notAfter the symmetric half-bridge flyback circuit 12a enters the intermittent mode, the control circuit 11 controls the auxiliary power tube Q in the asymmetric half-bridge flyback circuit 12a H The first preset time period T1 is turned off.
In S84, the auxiliary power tube is controlled to be turned on for a second preset turning-on duration T2.
The control circuit 11 is used for controlling the auxiliary power tube Q H After the first preset turn-off duration T1 is turned off, the auxiliary power tube Q is controlled H And conducting for a second preset conducting time period T2. The second preset on-time T2 may be less than a predetermined value. The predetermined value may be 25% of the resonance period of the resonant circuit in the half-bridge circuit 121. For example, the second preset on-time T2 may be 10% -15% of the resonant period, etc. Wherein the resonance time at which zero input corresponding resonance occurs in the resonant circuit is less than 25% of the resonance period.
The first preset turn-off duration T1 and the second preset turn-on duration T2 may be preset fixed values, or may be calculated by the control circuit 11. For example, the first preset off-period T1 and the second preset on-period T2 may be fixed values set in advance.
In S85, it is acquired whether the input voltage rises to be greater than or equal to the second voltage value. If the input voltage rises to be greater than or equal to the second voltage value, S86 is executed, otherwise, S83 is returned to.
The control circuit 11 detects the input voltage V in If said input voltage V is lower than said reference voltage in Rises to a second voltage value V or higher in2 It means that the asymmetric half-bridge flyback circuit 12a can exit the burst mode. If the input voltage V is in Rises to a voltage value greater than a second voltage value V in2 It means that the control circuit 111 needs to repeatedly execute S83-S84 until the input voltage V in Rises to or above the second voltage value V in2 。
In S86, the asymmetric half-bridge flyback circuit 12a is controlled to operate in a normal operating state.
The control circuit 11 responds to the voltage value of the input voltage Vin rising to be larger than or equal toIs equal to the second voltage value V in2 When the control circuit 11 is in the normal working state, the asymmetric half-bridge flyback circuit 12a is controlled to operate, that is, the control circuit 11 controls the main power tube Q L And the auxiliary power tube Q H Alternately switched on and off.
By adopting the control circuit of the asymmetric half-bridge flyback circuit provided by the embodiment of the application, when the input voltage is reduced to be smaller than the first voltage value, the asymmetric half-bridge flyback circuit stops working according to the conventional mode and enters the intermittent state control until the input voltage is increased to be larger than the second voltage value, and the asymmetric half-bridge flyback circuit starts working according to the conventional mode again. For example, in the intermittent state control of the asymmetric half-bridge flyback circuit, the control circuit controls the auxiliary power tube in the asymmetric half-bridge flyback circuit to be turned off by a first preset turn-off duration T1, and then controls the auxiliary power tube to be turned on by a second preset turn-on duration T2, where the second preset turn-on duration T2 is less than 25% of a resonant period of a resonant cavity formed by a resonant inductor and a resonant capacitor in the asymmetric half-bridge flyback circuit. Therefore, the current stress generated by the discharged current of the resonant capacitor on the auxiliary power tube, the transformer and the rectifier circuit can be reduced, the stable operation of the asymmetric half-bridge flyback circuit, the power supply module and the electronic equipment where the power supply module is arranged is ensured, and the service lives of the asymmetric half-bridge flyback circuit, the power supply module and the electronic equipment are prolonged.
Fig. 9 is a schematic flowchart of a control circuit for controlling an asymmetric half-bridge flyback circuit according to another embodiment of the present application.
In S91, the asymmetric half-bridge flyback circuit 12a is controlled to operate in a normal operating state.
Taking the power module 10 shown in fig. 4 as an example for explanation, the control circuit 11 can control the main power transistor Q L And the auxiliary power tube Q H Alternately switched on and off.
In S92, it is acquired whether the input voltage falls to less than or equal to the first voltage value. If the input voltage drops to be less than or equal to the first voltage value, S93 is executed, otherwise, S92 is returned to.
If soThe control circuit 11 detects the input voltage V in Falls to less than or equal to a first voltage value V in1 The control circuit controls the asymmetric half-bridge flyback circuit 12a to enter an intermittent state.
In S93, the auxiliary power transistor is controlled to be turned off.
In S94, collecting voltages at both sides of the resonant capacitor, and recording the voltage at both sides of the resonant capacitor as V cr_pre 。
In the auxiliary power tube Q H After the shutdown, the control circuit 11 may start to collect the voltages at the two sides of the resonant capacitor Cr, and record the collected voltages as V cr_pre 。
It will be appreciated that in some embodiments, the control circuit 11 may measure the voltage V across the resonant capacitor via a resistive divider network cr And may be converted to digital values by an analog-to-digital converter.
In S95, it is determined whether the turn-off time of the auxiliary power tube reaches a first preset turn-off duration. And executing S96 if the turn-off time of the auxiliary power tube reaches a first preset turn-off duration, otherwise, returning to S95.
In S96, the auxiliary power tube is controlled to be turned on for a second preset on duration.
The control circuit 11 is controlling the auxiliary power tube Q H After the first preset turn-off time T1 is turned off, the auxiliary power tube Q is controlled H And conducting for a second preset conducting time period T2. The second preset on-time T2 may be less than a predetermined value. The predetermined value may be 25% of the resonance period of the resonant circuit in the half-bridge circuit 121. For example, the second preset on-time T2 may be 10% -15% of the resonant period, etc. Wherein the resonance time at which zero input corresponding resonance occurs in the resonant circuit is less than 25% of the resonance period.
In S97, the auxiliary power transistor is controlled to be turned off.
In S98, the voltages at both sides of the resonant capacitor are collected, and the voltage at both sides of the resonant capacitor at this time is recorded as V cr 。
In the auxiliary power tube Q H After being shut down, theThe control circuit 11 may start to collect the voltages at both sides of the resonant capacitor Cr, and record the collected voltages as V cr . At this time, V cr Can be an auxiliary power tube Q H The resonant capacitor voltage before the next cycle is turned on. V cr_pre Can be an auxiliary power tube Q H The resonant capacitor voltage before the last cycle is turned on. In other words, the control circuit 11 may be responsive to the input voltage V in Falls to less than a first voltage value V in1 And the input voltage V in Rises to a value greater than the second voltage value V in2 In two consecutive first periods, the auxiliary power tube Q is obtained H The difference in the voltage of the resonant capacitor Cr before switching on. The duration of the first period is the sum of a first preset turn-off duration T1 and a second preset turn-on duration T2.
It can be understood that if the auxiliary power tube Q is in two consecutive first periods H The difference of the voltages of the resonant capacitors before the turn-on is not increased and the input voltage V in Rises to a value greater than the second voltage value V in2 The control circuit 11 can control the main power tube Q L And is turned on for a first duration in each second period. If the auxiliary power tube Q continues for two first periods H The difference of the voltages of the resonant capacitor Cr before turn-on increases and the input voltage V in Rises to a value greater than the second voltage value V in2 The control circuit 11 can control the main power tube Q L And conducting for a second duration during each second period. Wherein the second duration is greater than the first duration.
In S99, it is confirmed whether the override flag is 1. If yes, the process proceeds to S100, otherwise, the process proceeds to S101.
In S100, it is acquired whether the input voltage rises to be greater than or equal to a third voltage value. If the input voltage rises to be greater than or equal to the third voltage value, the process proceeds to S107. Otherwise, the process proceeds to S102.
The control circuit 11 can detect the input voltage V in And judging the input voltage V in Whether it rises to a value greater than or equal to the third voltage value V in3 。
In S101, it is detected whether the input voltage rises to be greater than or equal to a second voltage value. If the input voltage rises to be greater than or equal to the second voltage value, the process proceeds to S107. Otherwise, the process proceeds to S102.
It is understood that the control circuit 11 can also determine the input voltage V in Whether it rises to a value greater than or equal to a second voltage value V in2 。
In S102, V is confirmed cr And V cr_pre Pressure difference Δ V therebetween cr Whether it is less than a preset threshold. If Δ V cr And if the value is smaller than the preset threshold value, the step S103 is entered, otherwise, the step S104 is entered.
The control circuit 11 can be arranged at the auxiliary power tube Q H Collecting voltage V on two sides of resonant capacitor Cr before conducting cr And the voltage V cr And the last auxiliary power tube Q H V collected before conduction cr_pre And (4) subtracting.
In S103, it is determined that the power module is not overloaded.
In this embodiment, when the pressure difference Δ V cr Less than a predetermined threshold V th In this case, the control circuit 11 may determine that the power module 10 is not connected to the heavy load.
In S104, the power module is confirmed to be overloaded.
In this embodiment, when the pressure difference Δ V cr Greater than a predetermined threshold value V th The control circuit may then confirm that the power module 10 has been switched into a heavy load in the intermittent state.
It can be understood that if the auxiliary power tube Q is in two consecutive first periods H The difference of the voltages of the resonant capacitors before the conduction is less than a preset threshold value V th And the input voltage V in Rises to a value greater than the second voltage value V in2 The control circuit 11 can control the main power tube Q L And is turned on for a first duration in each second period. If the auxiliary power tube Q is in two consecutive first periods H Before the conduction, the difference value of the voltages of the resonance capacitor Cr is larger than a preset threshold value V th And the input voltage V in Rises to a value greater than the second voltage value V in2 The control circuit 11 can control the main power tube Q L And conducting for a second duration during each second period.
In S105, V is set cr Is given to V cr_pre 。
Subsequently, the control circuit 11 may also convert V cr Is given to V cr_pre 。
In S106, it is determined whether the turn-off time of the auxiliary power tube reaches a first preset turn-off duration. And if the turn-off time of the auxiliary power tube reaches the first preset turn-off duration, the step S96 is entered, otherwise, the step S106 is returned.
In S107, the asymmetric half-bridge flyback circuit 12a is controlled to operate in a normal operation state.
The present application further provides an electronic device including the control circuit 11 as provided in any embodiment of the present application, or including the power module 10 as provided in any embodiment of the present application.
In the foregoing embodiment, a method executed by the control circuit 11 provided in the embodiment of the present application is described, but in order to implement each function in the method provided in the embodiment of the present application, the control circuit 11 serving as an execution subject may include a hardware structure and/or a software module, and implement each function in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether any of the above functions is implemented as a hardware structure, a software module, or a combination of a hardware structure and a software module depends upon the particular application and design constraints imposed on the technical solution. It should be noted that the division of the modules of the above apparatus is only a logical division, and the actual implementation may be wholly or partially integrated into one physical entity, or may be physically separated. And these modules can be realized in the form of software called by processing element; or can be implemented in the form of hardware; and part of the modules can be realized in the form of calling software by the processing element, and part of the modules can be realized in the form of hardware. The processing element may be a separate processing element, or may be integrated into a chip of the apparatus, or may be stored in the memory of the apparatus in the form of program code, and a processing element of the apparatus may call and execute the functions of the above determination module. Other modules are implemented similarly. In addition, all or part of the modules can be integrated together or can be independently realized. The processing element described herein may be an integrated circuit having signal processing capabilities. In implementation, each step of the above method or each module above may be implemented by an integrated logic circuit of hardware in a processor element or an instruction in the form of software. For example, the above modules may be one or more integrated circuits configured to implement the above methods, such as: one or more Application Specific Integrated Circuits (ASICs), or one or more Digital Signal Processors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs), etc. For another example, when some of the above modules are implemented in the form of a processing element scheduler code, the processing element may be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor that can call program code. As another example, these modules may be integrated together, implemented in the form of a system-on-a-chip (SOC).
Although the present invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present invention.
Claims (10)
1. A power module is characterized by comprising an asymmetric half-bridge flyback circuit and a control circuit, wherein the asymmetric half-bridge flyback circuit is used for receiving an input voltage and providing an output voltage, the asymmetric half-bridge flyback circuit comprises a transformer, a resonant capacitor, a main power tube and an auxiliary power tube, and the control circuit is used for outputting a control signal to control the main power tube and the auxiliary power tube;
in response to the input voltage falling below a first voltage threshold, the auxiliary power tube is alternately turned off and turned on according to a first preset turn-off duration and a second preset turn-on duration;
in response to the input voltage rising to be greater than a second voltage threshold, the main power tube and the auxiliary power tube are alternately switched on and off;
and the ratio of the second preset conduction time length to the time length of the resonance period of the asymmetric half-bridge flyback circuit is less than or equal to 0.25.
2. The power module of claim 1, wherein the main power transistor is configured to:
responsive to the input voltage falling below the first voltage threshold, remain off in accordance with the control signal.
3. The power module as claimed in claim 1 or 2,
the transformer comprises a primary winding and a secondary winding, a source electrode of the main power tube is connected with a drain electrode of the auxiliary power tube and a first end of the primary winding, a source electrode of the auxiliary power tube is connected with a reference ground and one end of the resonant capacitor, the other end of the resonant capacitor is connected with a second end of the primary winding, the resonant capacitor discharges when the auxiliary power tube is switched on, and the resonant capacitor stops discharging when the auxiliary power tube is switched off.
4. The power module of any of claims 1-3, wherein the power module includes an auxiliary winding circuit for providing power to the control circuit, the auxiliary winding circuit including an auxiliary winding, the auxiliary winding being coupled to the primary winding.
5. A control circuit of an asymmetric half-bridge flyback circuit, the asymmetric half-bridge flyback circuit comprises a transformer, a resonant capacitor, a main power tube and an auxiliary power tube, and the control circuit is used for:
obtaining a comparison result of a voltage value of an input voltage of the asymmetric half-bridge flyback circuit and a first voltage threshold or a second voltage threshold;
in response to the voltage value of the input voltage falling to be smaller than a first voltage threshold, controlling the auxiliary power tube to be alternately turned off and turned on according to a first preset turn-off duration and a second preset turn-on duration;
controlling the main power tube and the auxiliary power tube to be alternately switched on and off in response to the voltage value of the input voltage rising to be larger than a second voltage threshold;
and the ratio of the second preset time length to the time length of the resonance period of the asymmetric half-bridge flyback circuit is less than or equal to 0.25.
6. The control circuit of claim 5, wherein the control circuit is configured to:
controlling the main power tube to remain off in response to the input voltage falling below the first voltage threshold.
7. The control circuit of claim 5 or 6, wherein the control circuit is configured to obtain the second preset on-duration according to a resonant period of the asymmetric half-bridge flyback circuit, or the control circuit is configured to obtain the second preset on-duration according to a resonant capacitance value and a resonant inductance value of the asymmetric half-bridge flyback circuit.
8. The control circuit of any of claims 5-7, wherein the control circuit is configured to:
responding to the situation that the input voltage is decreased to be smaller than the first voltage threshold and the situation that the input voltage is increased to be larger than the second voltage threshold, and acquiring a difference value of the voltage of the resonant capacitor before the auxiliary power tube is conducted in two continuous first periods, wherein the duration of the first period is the sum of a first preset turn-off duration and a second preset turn-on duration;
in response to the fact that the difference value of the voltages of the resonance capacitors before the auxiliary power tube is conducted in two consecutive first periods does not increase and the input voltage rises to be larger than the second voltage threshold value, controlling the main power tube to be conducted for a first time length in each second period;
in response to the difference value of the voltages of the resonance capacitors before the auxiliary power tube is conducted in two consecutive first periods being increased and the input voltage rising to be larger than the second voltage threshold, controlling the main power tube to be conducted for a second time length in each second period; wherein the second duration is greater than the first duration.
9. The control circuit of any of claims 5-7, wherein the control circuit is configured to:
responding to the situation that the input voltage is decreased to be smaller than the first voltage threshold and the situation that the input voltage is increased to be larger than the second voltage threshold, and acquiring a voltage difference value of the resonant capacitor before the auxiliary power tube is conducted in two continuous first periods, wherein the duration of the first period is the sum of a first preset turn-off duration and a second preset turn-on duration;
in response to that the difference value of the voltages of the resonance capacitors before the auxiliary power tube is conducted in two consecutive first periods is smaller than a third voltage threshold and the input voltage rises to be larger than the second voltage threshold, controlling the main power tube to be conducted for a first time length in each second period;
in response to the difference value of the voltages of the resonance capacitors before the auxiliary power tube is conducted in two consecutive first periods being larger than a third voltage threshold and the input voltage rising to be larger than the second voltage threshold, controlling the main power tube to be conducted for a second time period in each second period; wherein the second duration is greater than the first duration.
10. An electronic device comprising a power supply module as claimed in any one of claims 1 to 4, or a control circuit comprising an asymmetric half-bridge flyback circuit as claimed in any one of claims 5 to 9.
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