CN109450259B - Flyback switching power supply - Google Patents
Flyback switching power supply Download PDFInfo
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- CN109450259B CN109450259B CN201811550343.XA CN201811550343A CN109450259B CN 109450259 B CN109450259 B CN 109450259B CN 201811550343 A CN201811550343 A CN 201811550343A CN 109450259 B CN109450259 B CN 109450259B
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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
- H02M3/33576—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 having at least one active switching element at the secondary side of an isolation transformer
- H02M3/33592—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 having at least one active switching element at the secondary side of an isolation transformer having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary 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
- H02M1/0048—Circuits or arrangements for reducing losses
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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
Abstract
The invention provides a flyback switching power supply, which comprises a main circuit, a main circuit and a flyback switching power supply, wherein the main circuit comprises an alternating current input EMC unit, a multi-interleaving flyback switching circuit unit, a switching tube synchronous rectification unit, primary and secondary lossless clamping units, an output voltage holding unit, an output EMC unit, primary and secondary signal acquisition units, a switching signal driving unit and a first primary and secondary signal interface unit; the control circuit comprises a digital power supply controller unit, a standby power supply unit, a signal isolation unit, primary and secondary signal conditioning units, a communication programming interface unit and a second primary and secondary signal interface unit. The existing active flyback clamping method is improved into a primary passive flyback clamping method and a secondary passive flyback clamping method in the main circuit; the control circuit integrates the existing control module circuit with the standby power supply unit and the second primary and secondary signal isolation coupling circuit. The invention not only effectively improves the power supply conversion efficiency of the main circuit, limits the implementation cost and complexity of the circuit, but also simplifies the interface signal of the control circuit.
Description
Technical Field
The invention relates to the technical field of power supplies, in particular to a flyback switching power supply.
Background
The switching power supply is developed from a linear voltage-stabilized power supply, and has been widely popularized as a common article in life along with the high-speed development of the technology.
The switching power supply comprises a main circuit and a control circuit; in the main circuit part, the existing mainstream scheme adopts a single-stage switching power supply scheme, the switching circuit of the scheme adopts a flyback switching power supply topological circuit to obtain the optimal cost performance, but the electric energy conversion efficiency is low, and the fundamental reason is that the clamp circuit part in the switching circuit has fixed electric energy consumption, and the electric energy consumption of the clamp circuit part is multiplied along with the increase of the power supply; meanwhile, in the control circuit part, the existing mainstream scheme is only to integrate the digital switching power supply microprocessor and the related peripheral signal processing circuit, but with the improvement of the requirements of the functions and performance indexes of the switching power supply, the complexity of the control signals, the number of control objects and the total volume of the switching power supply are increased.
Although the clamp circuit part in the switch circuit is improved by adopting an active flyback clamping method in order to overcome the electric energy consumption of the clamp circuit part of the switch circuit in the main circuit part, the complexity and the cost of the circuit are obviously increased, and the practicability of the scheme is weakened; meanwhile, although the signal interface between the switching power supply and the control circuit thereof is simplified in order to overcome the complexity of the control circuit part and the number of control objects, improvement is still needed.
Disclosure of Invention
The technical problem to be solved by the embodiments of the present invention is to provide a flyback switching power supply, which improves both a main circuit and a control circuit in a conventional switching power supply, thereby not only effectively improving the power conversion efficiency of the main circuit, limiting the implementation cost and complexity of the circuit, but also simplifying the interface signal of the control circuit.
In order to solve the above technical problem, an embodiment of the present invention provides a flyback switching power supply, including a main circuit and a control circuit, where the main circuit includes a power conversion circuit and a signal control circuit; the power conversion circuit comprises an alternating current input EMC unit, a multi-interleaving flyback switching circuit unit, a primary lossless clamping unit, a switching tube synchronous rectification unit, a secondary lossless clamping unit, an output voltage holding unit and an output EMC unit; the signal control circuit comprises a primary signal acquisition unit, a secondary signal acquisition unit, a switching signal driving unit, a first primary signal interface unit and a first secondary signal interface unit; wherein the content of the first and second substances,
the alternating current input EMC unit is connected to the multi-interleaving flyback switching circuit unit and the primary signal acquisition unit, the multi-interleaving flyback switching circuit unit is connected to the primary signal acquisition unit, the switching tube synchronous rectification unit and the primary lossless clamping unit, the switching tube synchronous rectification unit is connected to the secondary lossless clamping unit, the secondary lossless clamping unit is connected to the output voltage holding unit, the output voltage holding unit is connected to the output EMC unit and the secondary signal acquisition unit, the secondary signal acquisition unit is connected with the first secondary signal interface unit, the primary signal acquisition unit is connected to the first primary signal interface unit, the first primary signal interface unit is connected to the switching signal driving unit, and the switching signal driving unit is connected to the multi-interleaving flyback switching circuit unit;
the control circuit comprises a standby power supply unit, a digital power supply controller unit, a signal isolation unit, a primary signal conditioning unit, a secondary signal conditioning unit, a communication programming interface unit, a second primary signal interface unit and a second secondary signal interface unit; wherein the content of the first and second substances,
the standby power supply unit is connected with the output voltage maintaining unit in the main circuit and is also connected to the digital power supply controller unit and the second primary signal interface unit, the digital power supply controller unit is mutually connected with the signal isolation unit and the communication programming interface unit and is also connected to the primary signal conditioning unit, the primary signal conditioning unit is connected to the second primary signal interface unit, the signal isolation unit is mutually connected with the secondary signal conditioning unit, and the secondary signal conditioning unit is connected to the second secondary signal interface unit.
The standby power supply unit comprises a step-down switch circuit formed by serially connecting an inductor FL1, a capacitor EC2 and a diode FD3, a flyback integrated switch U1 and a feedback resistor R1; wherein the content of the first and second substances,
a loop is formed by the flyback integrated switch U1 and the feedback resistor R1;
one end of the feedback resistor R1 is connected to the input end of the step-down switch circuit, and the other end is connected to the output voltage holding unit;
the output end of the voltage reduction switch circuit is connected to the digital power supply controller unit to form a working voltage source VCC required by the digital power supply controller unit.
The primary signal conditioning unit comprises a triode T1 and a resistor R12; wherein the content of the first and second substances,
the collector of the triode T1 is connected to the second primary signal interface unit, the emitter is connected to the digital power supply controller unit, and the base is connected to the input end of the resistor R12;
the output of resistor R12 forms the reference input signal source for the analog comparator in the digital power supply controller unit.
The secondary signal conditioning unit comprises an operational amplifier U3B, a photosensitive diode, a triode T2, a resistor R23 and a resistor R24; wherein the content of the first and second substances,
the positive input end of the operational amplifier U3B is connected to the second secondary signal interface unit, the negative input end is connected to the output end, and the output end is connected to the positive electrode of the photodiode and the collector of the triode T2;
the cathode of the photosensitive diode is connected to the base of the triode T2 and the input end of the resistor R23;
the emitter of the triode T2 is connected to the input end of the resistor R24;
the output terminal of the resistor R23 is connected to the output terminal of the resistor R24 and to ground.
The signal isolation unit comprises an optical coupler OC1 corresponding to the photosensitive diode and an adjustable resistor PT 1; wherein the content of the first and second substances,
the input end of the optical coupler OC1 corresponds to the photosensitive diode, and the output end of the optical coupler OC1 is connected to the input end of the adjustable resistor PT 1;
the output terminal of the adjustable resistor PT1 is grounded, and the adjustable terminal is connected to the digital power supply controller unit.
The multiple staggered flyback switch circuit units are formed by connecting multiple flyback switch circuit units in parallel, and the on and off of the switches in each flyback switch circuit unit are staggered in an equal phase mode at the same time.
The embodiment of the invention has the following beneficial effects:
the invention improves the prior active flyback clamping method into the primary and secondary passive flyback clamping methods in the main circuit, and integrates the prior control module circuit with the standby power supply unit and the primary and secondary signal isolation coupling circuits in the control circuit, thereby not only effectively improving the power supply conversion efficiency of the main circuit, limiting the implementation cost and complexity of the circuit, but also simplifying the interface signal of the control circuit.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.
Fig. 1 is a schematic block diagram of a flyback switching power supply according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of the main circuit of FIG. 1;
fig. 3 is a circuit connection diagram of the control circuit in fig. 1.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1, a flyback switching power supply provided in the embodiment of the present invention includes a main circuit and a control circuit.
The main circuit comprises a power conversion circuit and a signal control circuit; the power conversion circuit comprises an alternating current input EMC unit, a multi-interleaving flyback switching circuit unit, a primary lossless clamping unit, a switching tube synchronous rectification unit, a secondary lossless clamping unit, an output voltage holding unit and an output EMC unit; the signal control circuit comprises a primary signal acquisition unit, a secondary signal acquisition unit, a switching signal driving unit, a first primary signal interface unit and a first secondary signal interface unit; wherein the content of the first and second substances,
the alternating current input EMC unit is connected to the multi-interleaving flyback switching circuit unit and the primary signal acquisition unit, the multi-interleaving flyback switching circuit unit is connected to the primary signal acquisition unit, the switching tube synchronous rectification unit and the primary lossless clamping unit, the switching tube synchronous rectification unit is connected to the secondary lossless clamping unit, the secondary lossless clamping unit is connected to the output voltage holding unit, the output voltage holding unit is connected to the output EMC unit and the secondary signal acquisition unit, the secondary signal acquisition unit is connected with the first secondary signal interface unit, the primary signal acquisition unit is connected to the first primary signal interface unit, the first primary signal interface unit is connected to the switching signal driving unit, and the switching signal driving unit is connected to the multi-interleaving flyback switching circuit unit;
the control circuit comprises a standby power supply unit, a digital power supply controller unit, a signal isolation unit, a primary signal conditioning unit, a secondary signal conditioning unit, a communication programming interface unit, a second primary signal interface unit and a second secondary signal interface unit; wherein the content of the first and second substances,
the standby power supply unit is connected with the output voltage maintaining unit in the main circuit and is also connected to the digital power supply controller unit and the second primary signal interface unit, the digital power supply controller unit is mutually connected with the signal isolation unit and the communication programming interface unit and is also connected to the primary signal conditioning unit, the primary signal conditioning unit is connected to the second primary signal interface unit, the signal isolation unit is mutually connected with the secondary signal conditioning unit, and the secondary signal conditioning unit is connected to the second secondary signal interface unit.
In the embodiment of the invention, as shown in fig. 2, an alternating input voltage is converted into a high-voltage direct current HVDC1 through an alternating input EMC unit and a rectifier BR1, the high-voltage direct current HVDC1 is isolated and converted into a switching tube synchronous rectification unit through a multi-interleaved flyback switching circuit unit and a primary lossless clamping unit, an output voltage is maintained by a capacitor EC1 of an output voltage maintaining unit after passing through a secondary lossless clamping unit, and the voltage is finally supplied to a load after passing through an output EMC unit.
Three capacitors CY4, CY5 and CX1 in the alternating current input EMC unit are connected in parallel, so that the effect of interference suppression is better; common-mode inductors LC1, CY4 and CY5 are used for eliminating common-mode interference, and CX1, CY2 and CY3 are used for eliminating series-mode interference; GDT1 is a discharge tube, which can discharge the charge accumulated on CX1 to prevent the filter characteristics from being affected by the accumulation of charge; the inlet lines LN1, NU1 of the power supply can also be de-energized after the power supply is disconnected, which can greatly improve the safety of the power supply.
The multiple staggered flyback switch circuit units are formed by connecting the multiple flyback switch circuit units in parallel, and the on and off of the switches in each flyback switch circuit unit are staggered in an equal phase at the same time, so that the overall working performance is improved.
The primary lossless clamping unit comprises a primary passive clamping circuit consisting of an inductor and a capacitor which are connected in series. The inductor is a primary coil of a transformer XFERM 1, one end of the inductor is connected to pin 1 of a transformer XFERM 1 and is also connected with a switching tube Q1; the other side is connected to the 9-pin of the transformer and to one end of a capacitor CL2, the other end of the capacitor CL2 is connected to ground, and the coil forming the inductor shares the same magnetic circuit with the transformer XFRM 1. When the switching tube Q1 is turned on, the current passing through the switching tube Q1 includes the discharge current of the capacitor CL2 to the inductor in the primary passive clamp circuit in addition to the energy storage inductor current of the primary coil of the transformer XFRM1, and at this time, the electric energy absorbed by the capacitor CL2 is converted into the magnetic energy of the inductor without loss, and contributes to the energy storage process together with the energy storage inductor current of the primary coil of the transformer XFRM 1. When the switching tube Q2 is turned off, the electric energy of the instantaneous rebound potential on the primary coil of the transformer XFRM1 is stored on the capacitor CL2 in the primary clamping circuit through the inductor in the primary passive clamping circuit, so that the electric energy of the instantaneous rebound potential is nondestructively inhibited, and the instantaneous rebound voltage loaded on the switching tube Q1 is inhibited; in addition, since the inductor in the primary clamping circuit is in the same magnet as the primary coil of the transformer XFRM1, but the induced potential is opposite in polarity, the inductor potential at this moment is favorable for further suppressing the electric energy of the instantaneous bounce potential, so that the instantaneous bounce voltage carried on the switching tube Q1 is further suppressed, and the clamping effect can be adjusted by the magnitude of the capacitance.
The secondary lossless clamping unit comprises a secondary clamping circuit consisting of an inductor FL1 and a capacitor CL1 which are connected in series. When the switching tube Q2 is turned on, the primary side of the transformer XFRM1 is at the energy storage time, and there is no current in the secondary side, and at this time, the electric energy stored in the energy storage capacitor CL1 in the secondary clamping circuit is released to the inductor, and the electric energy absorbed by the capacitor can be converted into the current in the inductor without loss, and contributes to the output load together with the current of the magnetic energy in the inductor. When the switching tube Q2 is turned off, the electric energy of the instantaneous bounce potential of the primary side of the transformer XFRM1 is coupled to the energy storage capacitor CL1 in the secondary clamping circuit through the secondary coil, the electric energy of the bounce potential is quickly absorbed by the capacitor CL1 in an energy storage manner, the electric energy of the instantaneous bounce potential on the switch Q2 is nondestructively suppressed, the inductor is used for recovering the transient voltage energy absorbed by the capacitor to the output voltage holding unit during the non-output period of the transformer, and the clamping effect of the electric energy can also be adjusted by the capacitance of the CL 1. Because no energy consumption element or active element participates in energy storage and recovery in the two clamping networks, the two clamping networks are lossless clamping networks.
In the primary signal acquisition unit, a switching current flowing through a switching tube 2 extracts a signal on a current sampling resistor RS1 to be Icsm; the zero-crossing signal of the switching voltage and the capacitor CC1 become ZCM; the over-voltage monitoring signal of the switch voltage and the over-resistance R2 become a sampling signal Vsw; the input voltage monitoring signal and the over-resistance R1 become the sampling signal Vac; the AC input signal becomes a sampling signal Vacc through D1, D2 and R4; the five signals are all connected into the first primary signal interface unit for power supply control and analysis.
In the secondary signal acquisition unit, the output current flowing through the LED load extracts a signal on a current sampling resistor RS2 to be Idco; the output voltage VDC loaded on the LED load becomes a sampling signal Vdco through a resistor R7; the output voltage VDC extracts a signal Vs in a voltage stabilizing circuit formed by the output voltage VDC and is used as power supply of a secondary signal circuit; the three signals are all connected into a first secondary signal interface unit for power supply control and analysis.
The power controllers in the first primary signal interface unit and the first secondary signal interface unit generate a switching signal MSR after analyzing an input signal, and interleaving switching signals SLV1, SLV2 and SLV3 which become DM, … and DS3 after passing through a driver DR3, namely DR4, and access switching tubes Q2, … and Q4 to control the switching working state of the circuit.
In the embodiment of the present invention, as shown in fig. 3, the standby power supply unit includes a buck switch circuit formed by serially connecting an inductor FL1, a capacitor EC2, and a diode FD3, a flyback integrated switch U1, and a feedback resistor R1; the flyback integrated switch U1 and the feedback resistor R1 form a loop; one end of the feedback resistor R1 is connected to the input end of the step-down switch circuit, and the other end is connected to the output voltage holding unit; the output end of the voltage reduction switch circuit is connected to the digital power supply controller unit to form a working voltage source VCC required by the digital power supply controller unit.
At this time, the output voltage Vp of the buck switch circuit is transmitted to the input end VDD of the flyback integrated switch U1 through the diodes FD2 and FD1, so that the buck switch circuit can work in a closed loop; resistor R1 is provided for activation of flyback integrated switch U1. The input voltage is input from the HV end, and after passing through the unit, the driving voltage source Vp required by the switch power supply circuit is generated, and meanwhile, the working voltage source VCC required by the digital power supply controller unit is generated.
In the embodiment of the present invention, as shown in fig. 3, the primary signal conditioning unit includes a transistor T1 and a resistor R12; wherein, the collector of the triode T1 is connected to the second primary signal interface unit, the emitter is connected to the digital power controller unit, and the base is connected to the input end of the resistor R12; the output of resistor R12 forms the reference input signal source for the analog comparator in the digital power supply controller unit.
The primary signal conditioning unit is a single-phase digital-to-analog multiplier and is used for generating a reference input signal of a comparator. The digital pwm signal Pcp3 is derived from the digital power controller unit, and it acts on the analog signal Vacc from the second primary signal interface unit through the resistor R12 and the transistor T1 to generate the signal Icp3, which is provided to the reference input of the analog comparator inside the digital power controller unit MCU1, in the relationship Icp 3: Vacc Pcp 3.
In the embodiment of the present invention, as shown in fig. 3, the secondary signal conditioning unit includes an operational amplifier U3B, a photodiode, a transistor T2, a resistor R23, and a resistor R24; the positive input end of the operational amplifier U3B is connected to the second secondary signal interface unit, the negative input end is connected to the output end, and the output end is connected to the positive electrode of the photodiode and the collector of the triode T2; the cathode of the photosensitive diode is connected to the base of the triode T2 and the input end of the resistor R23; the emitter of the triode T2 is connected to the input end of the resistor R24; the output terminal of the resistor R23 is connected to the output terminal of the resistor R24 and to ground.
The secondary signal conditioning unit is a nonlinear correction circuit and is used for proportionally transmitting a sampling signal to the signal isolation unit; the sampling signal Idco from the second secondary signal interface unit flows into a common nonlinear photosensitive diode after passing through an operational amplifier U3B; the current passing through the photosensitive diode is sampled by the resistor R23 and transmitted to the triode T2 to play a role of shunting the current of the photosensitive diode, at the moment, the nonlinearity of the current and the nonlinearity of the triode become a complementary relation, and the magnitude of the complementary effect is determined by the resistors R23 and R24.
In the embodiment of the present invention, as shown in fig. 3, the signal isolation unit includes an optical coupler OC1 corresponding to the photodiode and an adjustable resistor PT 1; the input end of the optical coupler OC1 corresponds to the photosensitive diode, and the output end of the optical coupler OC1 is connected to the input end of the adjustable resistor PT 1; the output terminal of the adjustable resistor PT1 is grounded, and the adjustable terminal is connected to the digital power supply controller unit.
The signal isolation unit receives the signal corrected by the secondary signal conditioning unit, and the signal is transmitted to the adjustable resistor PT1 through the photoelectric coupler OC1 and then is transmitted to the Icso end of the digital power supply controller unit.
In the embodiment of the present invention, as shown in fig. 3, the communication programming interface unit is a communication and programming two-in-one interface unit. When the digital power controller unit MCU1 needs to be configured or programmed, four signal pins Nrst, Swim, Vp and GND are used; when the digital power controller unit MCU1 needs to communicate during operation, four signal pins RX, TX, Vp and GND are used.
In an embodiment of the invention, as shown in fig. 3, in the second primary signal interface unit, 1, HV working input voltage source (600 Vpk-max); 2. vac input voltage sampling signal (1V2max,3k to GND); 3. GND primary ground; 4. vp primary output voltage (12V,300 mA); 5. vsw switch voltage sampling signal (1V2max,1k5to GND); 6. a vacc switch current comparator reference input signal; 7. URXI/O port; 8. a UTX I/O port; 9. the Icsm switching current comparator samples the input signal (1V2 max); 10. PWM1 pulse signal, master (10k to GND); 11. PWM2 pulse signal, from 1(10k to GND); 12. PWM5 pulse signal, from 2(10k to GND); 13. PWM4 pulse signal, from 3(10k to GND); 14. ZCm zero crossing detection signal (10k to MCU); 15. a DIN logic input; 16. GND primary ground
In the second secondary signal interface unit, 1, Vdco outputs a voltage sampling signal (4.7Vovp,3k toGNDS)2, Idco outputs a current sampling signal (100mVocp)3, GNDS secondary ground 4, Vs secondary input voltage (12V,20 mA).
The embodiment of the invention has the following beneficial effects:
the invention improves the prior active flyback clamping method into the primary and secondary passive flyback clamping methods in the main circuit, and integrates the prior control module circuit with the standby power supply unit and the primary and secondary signal isolation coupling circuits in the control circuit, thereby not only effectively improving the power supply conversion efficiency of the main circuit, limiting the implementation cost and complexity of the circuit, but also simplifying the interface signal of the control circuit.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (1)
1. A flyback switching power supply comprises a main circuit and a control circuit, and is characterized in that the main circuit comprises a power conversion circuit and a signal control circuit; the power conversion circuit comprises an alternating current input EMC unit, a multi-interleaving flyback switching circuit unit, a primary lossless clamping unit, a switching tube synchronous rectification unit, a secondary lossless clamping unit, an output voltage holding unit and an output EMC unit; the signal control circuit comprises a primary signal acquisition unit, a secondary signal acquisition unit, a switching signal driving unit, a first primary signal interface unit and a first secondary signal interface unit; wherein the content of the first and second substances,
the alternating current input EMC unit is connected to the multi-interleaving flyback switching circuit unit and the primary signal acquisition unit, the multi-interleaving flyback switching circuit unit is connected to the primary signal acquisition unit, the switching tube synchronous rectification unit and the primary lossless clamping unit, the switching tube synchronous rectification unit is connected to the secondary lossless clamping unit, the secondary lossless clamping unit is connected to the output voltage holding unit, the output voltage holding unit is connected to the output EMC unit and the secondary signal acquisition unit, the secondary signal acquisition unit is connected with the first secondary signal interface unit, the primary signal acquisition unit is connected to the first primary signal interface unit, the first primary signal interface unit is connected to the switching signal driving unit, and the switching signal driving unit is connected to the multi-interleaving flyback switching circuit unit;
the control circuit comprises a standby power supply unit, a digital power supply controller unit, a signal isolation unit, a primary signal conditioning unit, a secondary signal conditioning unit, a communication programming interface unit, a second primary signal interface unit and a second secondary signal interface unit; wherein the content of the first and second substances,
the standby power supply unit is connected with the output voltage holding unit in the main circuit and is also connected to the digital power supply controller unit and the second primary signal interface unit, the digital power supply controller unit is connected with the signal isolation unit and the communication programming interface unit and is also connected to the primary signal conditioning unit, the primary signal conditioning unit is connected to the second primary signal interface unit, the signal isolation unit is connected with the secondary signal conditioning unit, and the secondary signal conditioning unit is connected to the second secondary signal interface unit;
the alternating current input voltage is converted into high-voltage direct current HVDC1 through an alternating current input EMC unit and a rectifier BR1, the high-voltage direct current HVDC1 is isolated and converted into a switching tube synchronous rectification unit through a multi-interleaving flyback switching circuit unit and a primary lossless clamping unit, the output voltage is kept by a capacitor EC1 of an output voltage keeping unit after passing through a secondary lossless clamping unit, and the voltage is finally supplied to a load after passing through an output EMC unit; the primary lossless clamping unit comprises a primary passive clamping circuit consisting of an inductor and a capacitor which are connected in series; the inductor is a primary coil of a transformer XFERM 1, one end of the inductor is connected to pin 1 of a transformer XFERM 1 and is also connected with a switching tube Q1; the other side is connected to a pin 9 of the transformer and is connected with one end of a capacitor CL2, the other end of the capacitor CL2 is grounded, and a coil forming the inductor shares the same magnetic circuit with the transformer XFERM 1;
the standby power supply unit comprises a step-down switch circuit formed by serially connecting an inductor FL1, a capacitor EC2 and a diode FD3, a flyback integrated switch U1 and a feedback resistor R1; wherein the content of the first and second substances,
a loop is formed by the flyback integrated switch U1 and the feedback resistor R1;
one end of the feedback resistor R1 is connected to the input end of the step-down switch circuit, and the other end is connected to the output voltage holding unit;
the output end of the voltage reduction switch circuit is connected to the digital power supply controller unit to form a working voltage source VCC required by the digital power supply controller unit;
the primary signal conditioning unit comprises a triode T1 and a resistor R12; wherein the content of the first and second substances,
the collector of the triode T1 is connected to the second primary signal interface unit, the emitter is connected to the digital power supply controller unit, and the base is connected to the input end of the resistor R12;
the output end of the resistor R12 is formed as a reference input signal source of an analog comparator in the digital power supply controller unit;
the secondary signal conditioning unit comprises an operational amplifier U3B, a photosensitive diode, a triode T2, a resistor R23 and a resistor R24; wherein the content of the first and second substances,
the positive input end of the operational amplifier U3B is connected to the second secondary signal interface unit, the negative input end is connected to the output end, and the output end is connected to the positive electrode of the photodiode and the collector of the triode T2;
the cathode of the photosensitive diode is connected to the base of the triode T2 and the input end of the resistor R23;
the emitter of the triode T2 is connected to the input end of the resistor R24;
the output end of the resistor R23 is connected to the output end of the resistor R24 and grounded;
the signal isolation unit comprises an optical coupler OC1 corresponding to the photosensitive diode and an adjustable resistor PT 1; wherein the content of the first and second substances,
the input end of the optical coupler OC1 corresponds to the photosensitive diode, and the output end of the optical coupler OC1 is connected to the input end of the adjustable resistor PT 1;
the output end of the adjustable resistor PT1 is grounded, and the adjustable end is connected to the digital power supply controller unit;
the multiple staggered flyback switch circuit units are formed by connecting multiple flyback switch circuit units in parallel, and the on and off of the switches in each flyback switch circuit unit are staggered in an equal phase at the same time.
Priority Applications (1)
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| CN107666248A (en) * | 2017-08-23 | 2018-02-06 | 广路智能科技有限公司 | A kind of isolated LED switch power supply of monopole |
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