CN115276415A - Output constant voltage control system of single-ended flyback switching power supply - Google Patents
Output constant voltage control system of single-ended flyback switching power supply Download PDFInfo
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- CN115276415A CN115276415A CN202210868031.3A CN202210868031A CN115276415A CN 115276415 A CN115276415 A CN 115276415A CN 202210868031 A CN202210868031 A CN 202210868031A CN 115276415 A CN115276415 A CN 115276415A
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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
- H02M3/33507—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 with automatic control of the output voltage or current, e.g. flyback converters
- H02M3/33523—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 with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
-
- 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
- H02M3/33507—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 with automatic control of the output voltage or current, e.g. flyback converters
- H02M3/33515—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 with automatic control of the output voltage or current, e.g. flyback converters with digital control
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Abstract
The application relates to the field of single-ended flyback switching power supplies, in particular to a constant voltage control system for single-ended flyback switching power supply output, which comprises: the frequency feedback module is electrically connected with the pulse width modulation module and is used for regulating and controlling the frequency of the pulse width modulation module so as to realize the regulation and control of the voltage; the input end of the control module is connected with the output end of the single-ended flyback switching power supply, compares the received voltage with a threshold voltage and outputs a corresponding control signal; and the input end of the execution module is used for receiving the control signal, and the output end of the execution module is used for outputting the execution signal to the frequency feedback module so as to control whether the frequency feedback module is conducted or not. The single-ended flyback switching power supply has the effect that the output voltage of the single-ended flyback switching power supply is more stable.
Description
Technical Field
The application relates to the field of single-ended flyback switching power supplies, in particular to an output constant voltage control system of a single-ended flyback switching power supply.
Background
Along with the gradual improvement of the utilization rate of an inverter welding machine on a welding site, an inverter welding power supply is more and more important, the transformer used by the traditional power supply is large in size, so that the power consumption of the traditional power supply is large, the carrying is difficult, and the transformer used by the switching power supply is small in size, so that the power consumption of the switching power supply is small, and the carrying is convenient.
The switch power supply controls the on-off time ratio of the switch tube by utilizing the modern electronic power technology. A power supply maintains a stable output voltage. The switching power supply is generally composed of a Pulse Width Modulation (PWM) module, a control IC, and a MOSFET. The single-ended flyback switching power supply is a power supply circuit with the lowest cost, the output power is 20-100W, different voltages can be output simultaneously, and the voltage regulation rate is better.
With respect to the related art among the above, the inventors consider that the following drawbacks exist: when the single-ended flyback switching power supply changes in the power-on transient or suddenly due to a load, the output voltage fluctuates greatly, and once the voltage fluctuation output by the single-ended flyback switching power supply is severe, the quality of a welded workpiece is greatly influenced in the welding process.
Disclosure of Invention
In order to solve the problem that when a single-ended flyback switching power supply is in a power-on transient state or changes suddenly due to a load, the output voltage of the single-ended flyback switching power supply fluctuates greatly, the application provides an output constant voltage control system of the single-ended flyback switching power supply.
The application provides a single-ended flyback switching power supply output constant voltage control system adopts following technical scheme:
a single-ended flyback switching power supply output constant voltage control system comprises:
the frequency feedback module is electrically connected with the pulse width modulation module and is used for regulating and controlling the frequency of the pulse width modulation module so as to realize the regulation and control of voltage;
the input end of the control module is connected with the output end of the single-ended flyback switching power supply, the received voltage is compared with the threshold voltage, and a corresponding control signal is output;
and the input end of the execution module is used for receiving the control signal, and the output end of the execution module is used for outputting the execution signal to the frequency feedback module so as to control whether the frequency feedback module is conducted or not.
By adopting the technical scheme, when the output voltage of the single-ended flyback switching power supply is reduced due to the increase of the load, the control module receives the output voltage and compares the output voltage with the threshold voltage, when the output voltage is smaller than the threshold voltage, the control module outputs a corresponding control signal to the execution module, the execution module receives the control signal and then outputs the execution signal to the frequency feedback module, the frequency feedback module is conducted, the output frequency of the pulse width modulation module is regulated and controlled, the output power is improved, the output voltage is driven to rise, and the voltage stabilizing effect is achieved.
Optionally, the control module includes:
the input end of the first voltage division sub-module is connected with the output end of the single-ended flyback switching power supply, and the first voltage division sub-module is used for dividing the input voltage through a resistor and outputting a corresponding first voltage division signal;
the input end of the second voltage division submodule is connected with the output end of the single-ended flyback switching power supply and is used for dividing the input voltage through the voltage stabilizing diode and outputting a corresponding second voltage division signal;
and the input end of the comparison submodule is used for receiving the first voltage division signal and the second voltage division signal, comparing the first voltage division signal with the second voltage division signal and outputting a corresponding comparison signal.
By adopting the technical scheme, the output voltage is sampled simultaneously through the first voltage division submodule and the second voltage division submodule, the output voltage is divided through the resistor or the voltage stabilizing diode, and then the divided comparison submodules are compared, because the voltage stabilizing diode has conduction voltage, namely when the output voltage is greater than the conduction voltage, the voltage stabilizing diode is conducted (namely, the voltage stabilizing diode can be regarded as a lead, the resistance is greatly reduced), and when the output voltage is less than the conduction voltage, the voltage stabilizing diode can be regarded as an open circuit, the resistance is greatly increased, so that the effect of comparing with the threshold voltage is achieved, and then a corresponding comparison signal is sent to the execution module to control the frequency feedback module.
Optionally, the control module further includes:
and the input end of the amplification submodule is used for receiving the comparison signal, amplifying the comparison signal and outputting a corresponding amplification signal to the execution module, wherein the amplification signal is a control signal.
By adopting the technical scheme, the comparison sub-module amplifies the comparison signal through the amplification sub-module after outputting the comparison signal, and then outputs the amplified signal to the execution module, so that the conversion between digital electricity and analog electricity is realized, the comparison signal forms the amplified signal after amplification and can directly supply power to the execution module, the dual functions of power supply and signal control are realized, the power supply input to the execution module is reduced, and the number of power supply ends in a circuit is reduced.
Optionally, the execution module includes an optocoupler relay U1, the frequency feedback module includes a frequency modulation resistor R1, the frequency modulation resistor R1 is connected in parallel with the pulse width modulation module, a photoresistor end of the optocoupler relay U1 is connected in series to the frequency modulation resistor R1 and is used for controlling whether a circuit of the frequency modulation resistor R1 is switched on, and an output end of the amplifier sub-module is connected to an anode of a light emitting diode of the optocoupler relay U1.
Through adopting above-mentioned technical scheme, receive the corresponding amplified signal of amplifier submodule output when optical coupling relay U1's emitting diode, and the amplified signal is the high level, amplifier submodule will supply power to emitting diode, make emitting diode send light and shine on optical coupling relay U1's photo resistance end, thereby make the resistance of photo resistance end reduce (photo resistance end can be seen as the wire this moment), make the circuit resistance at photo resistance end place reduce, the current increase, make frequency modulation resistance R1 incorporate into the pulse width modulation module (can regard as only frequency modulation resistance R1 to incorporate into this moment), thereby the resistance of pulse width modulation module when pulse width modulation has been reduced, thereby the frequency has been improved, power has been improved, thereby make voltage rise, the effect of stabilizing voltage has been played, and whether control frequency modulation resistance R1 incorporates into through optical coupling relay U1, make circuit structure still realize frequency modulation's effect when simple, greatly reduced the cost of production, still reduced the cost that work maintenance personnel understood the circuit.
Optionally, the first voltage division submodule includes a first resistor R2 and a second resistor R3, one end of the first resistor R2 is connected to one end of the second resistor R3, the other end of the first resistor R2 is connected to the output end of the single-ended flyback switching power supply, the other end of the second resistor R3 is connected to the ground GND1, and the first resistor R2 and the second resistor R3 output a corresponding first voltage division signal as an output end.
Through adopting above-mentioned technical scheme, come the back of taking a sample to output voltage at first partial pressure submodule, the output voltage that the sample came will be divided the part away by second resistance R3, the voltage of first partial pressure signal is decided according to the resistance ratio of first resistance R2 and second resistance R3, and the resistance of first resistance R2 and second resistance R3 is fixed and is made the resistance ratio fixed, thereby it is fixed to make output voltage be divided the voltage percentage of going away, make the voltage that the partial pressure goes out fixed with output voltage's ratio, make the ratio of partial pressure more stable, thereby make the comparison result of both voltages after first partial pressure submodule and the partial pressure of second partial pressure submodule more stable.
Optionally, the second voltage division sub-module includes a third resistor R4 and a first zener diode ZD1, one end of the third resistor R4 is connected to the output end of the single-ended flyback switching power supply, the other end of the third resistor R4 is connected to the anode of the first zener diode ZD1, the cathode of the first zener diode ZD1 is connected to the ground GND1, and a corresponding second voltage division signal is output as an output end between the third resistor R4 and the anode of the first zener diode ZD 1.
By adopting the technical scheme, after the second voltage division submodule samples the output voltage, the sampled output voltage is divided by the first voltage stabilizing diode ZD1, the first voltage stabilizing diode ZD1 has a conduction voltage, and the conduction voltage is a compared threshold voltage, when the output voltage is greater than the threshold voltage, the first voltage stabilizing diode ZD1 is conducted, at the moment, the first voltage stabilizing diode ZD1 can be regarded as a conducting wire, when the output voltage is less than the threshold voltage, the first voltage stabilizing diode ZD1 is not conducted, at the moment, the first voltage stabilizing diode ZD1 can be regarded as an open circuit, so that when the output voltage fluctuates near the threshold voltage, the obtained second voltage division signal is changed remarkably, the comparison result between the first voltage division signal and the second voltage division signal is more accurate, the probability that the comparison result between the first voltage division signal and the second voltage division signal is wrong due to errors when the output voltage fluctuates in a small amplitude is reduced, and the comparison accuracy is improved.
Optionally, the comparison sub-module includes an operation comparator U2, an inverting input terminal of the operation comparator U2 is configured to receive the first voltage division signal, a homodromous input terminal of the operation comparator U2 is configured to receive the second voltage division signal, and an output terminal of the operation comparator U2 is configured to output a corresponding comparison signal.
By adopting the technical scheme, when the output voltage is reduced to be less than the threshold voltage, the first voltage stabilizing diode ZD1 is difficult to conduct, at the moment, the output voltage can be directly input to the in-phase input end of the operation comparator U2, and the output voltage input to the reverse input end still needs to be divided by the second resistor R3, so that the voltage of the in-phase input end is greater than the voltage of the reverse input end, at the moment, the operation comparator U2 outputs a high-level comparison signal, finally, the frequency feedback module works to improve the frequency and improve the voltage, and the voltage is pulled back to realize the stability of the voltage.
Optionally, the amplifying submodule includes a triode Q1, a base of the triode Q1 is used for receiving a comparison signal, a collector of the triode Q1 is used for being connected with an output end of the single-ended flyback switching power supply, an emitter of the triode Q1 is connected with an anode of a light emitting diode of the optocoupler relay U1, and a cathode of the light emitting diode of the optocoupler relay U1 is connected with a ground terminal GND 1.
By adopting the technical scheme, when the operation comparator U2 outputs a high-level comparison signal to the base electrode of the triode Q1, the collector electrode and the emitter electrode of the triode Q1 are conducted, so that the comparison signal of the operation comparator U2 is amplified and an amplified signal is output to the anode of the light emitting diode of the optocoupler relay U1, and the power supply control of the light emitting diode is realized to realize the control of a channel of the frequency feedback module.
In summary, the present application includes at least one of the following beneficial technical effects:
1. when the output voltage is smaller than the threshold voltage, the resistance of the pulse width modulation module is reduced, the output frequency of the pulse width modulation module is increased and regulated, so that the output power is increased, the output voltage is driven to rise, and the voltage stabilization effect is achieved; meanwhile, a control mode that the single-ended flyback switching power supply has pulse width modulation and frequency modulation (namely PWM + PFM) closed-loop control is created originally, and the purpose of accurately controlling the constant voltage output of the single-ended flyback switching power supply in the inverter welding power supply is achieved.
2. The power supply input to the execution module is reduced, the number of power supply ends in the circuit is reduced, the frequency modulation effect is achieved while the circuit structure is simple, the production cost is greatly reduced, the cost for workers to understand the circuit is reduced, the comparison result of the voltage of the first voltage division submodule and the voltage of the second voltage division submodule is more stable, and the comparison accuracy is improved.
Drawings
Fig. 1 is a block diagram of an output constant voltage control system of a single-ended flyback switching power supply in an embodiment of the present application.
Fig. 2 is an overall circuit diagram of an output constant voltage control system of a single-ended flyback switching power supply in an embodiment of the present application.
Description of the reference numerals: 1. a frequency feedback module; 2. a control module; 21. a first voltage divider sub-module; 22. a second voltage-dividing sub-module; 23. a comparison submodule; 24. an amplification submodule; 3. and executing the module.
Detailed Description
The present application is described in further detail below with reference to figures 1-2.
The embodiment of the application discloses a single-ended flyback switching power supply output constant voltage control system. Referring to fig. 1, the output constant voltage control system of the single-ended flyback switching power supply includes the single-ended flyback switching power supply, and the single-ended flyback switching power supply includes a first power supply CN1 (e.g., a socket), a high-frequency transformer T1 and a pulse width modulation module, in this embodiment, the high-frequency transformer T1 is a switching power supply transformer with a model specification of EE25+ turn ratio. A first pin of the first power supply terminal CN1 is connected to a primary winding 98 of the high-frequency transformer T1, a third pin of the first power supply terminal CN1 is connected to a ground terminal GND, electric energy on the primary winding 98 is coupled to the secondary winding 7, the secondary winding 8 and the secondary winding 13 through a magnetic core of the high-frequency transformer T1, the secondary winding 13 outputs +24V, the secondary winding 8 outputs +15V, output terminals of the secondary winding 13 and the secondary winding 8 are output terminals of the single-ended flyback switching power supply, and phase sequences of the primary winding 98, the secondary winding 7, the secondary winding 8 and the secondary winding 13 are in the same direction.
The pulse width modulation module includes a pulse width modulation chip U3, in this embodiment, the pulse width modulation chip U3 adopts an SD6835 switching power supply pulse width modulation chip, a seventh pin VCC of the pulse width modulation chip U3 is connected between the first pin of the first power supply terminal CN1 and the primary winding 98 of the high-frequency transformer T1, and the secondary winding 7 is connected to the seventh pin VCC of the pulse width modulation chip U3, so as to implement voltage compensation for the seventh pin VCC of the pulse width modulation chip U3. An oscillation resistor R5 is connected between a fourth pin RT/CT and an eighth pin VREF of the pulse width modulation chip U3, a frequency feedback module 1 is connected to the oscillation resistor R5 in parallel, and the frequency feedback module 1 is used for adjusting the resistance value of the oscillation resistor R5 connected between the fourth pin RT/CT and the eighth pin VREF of the pulse width modulation chip U3 so as to regulate and control voltage.
A field effect transistor Q2 is connected to a sixth pin OUT of the pulse width modulation chip U3, a gate of the field effect transistor Q2 is connected to the sixth pin OUT of the pulse width modulation chip U3, one end of the primary winding 98 is connected to a first pin of the first power supply terminal CN1, the other end of the primary winding 98 is connected to a drain of the field effect transistor Q2, and a source of the field effect transistor Q2 is connected to a third pin ISEN of the pulse width modulation chip U3.
The control module 2 is also included, and the input end of the control module is connected with the secondary winding 13 and the output end of the secondary winding 8, compares the received voltage with the threshold voltage, and outputs a corresponding control signal. The control module 2 includes a first voltage dividing sub-module 21, a second voltage dividing sub-module 22, a comparison sub-module 23, and an amplification sub-module 24.
The inputs of the first voltage-dividing submodule 21 and the second voltage-dividing submodule 22 are each connected to the output of the secondary winding 13. The first voltage dividing sub-module 21 includes a first resistor R2 and a second resistor R3, one end of the first resistor R2 is connected to one end of the second resistor R3, the other end of the first resistor R2 is connected to the output end (i.e., + 24V) of the secondary winding 13, the other end of the second resistor R3 is connected to the ground GND1, the voltage between the first resistor R2 and the second resistor R3 is controlled by the resistance ratio between the second resistor R3 and the first resistor R2, and the first resistor R2 and the second resistor R3 serve as output ends to output corresponding first voltage dividing signals.
The second voltage division submodule 22 includes a third resistor R4 and a first zener diode ZD1, one end of the third resistor R4 is connected to the output end (i.e., + 24V) of the secondary winding 13, the other end of the third resistor R4 is connected to the anode of the first zener diode ZD1, the cathode of the first zener diode ZD1 is connected to the ground GND1, the regulation and control of the voltage between the third resistor R4 and the first zener diode ZD1 are realized through the cooperation between the resistance value of the third resistor R4 and the conduction voltage of the first zener diode ZD1, and a corresponding second voltage division signal is output as an output end between the third resistor R4 and the anode of the first zener diode ZD 1.
The comparison submodule 23 includes an operation comparator U2, and in this embodiment, the operation comparator U2 is of an lm121 model. The power supply of the operation comparator U2 is +15V to-15V, a fourth resistor R6 is connected to the reverse input end of the operation comparator U2, and the other end of the fourth resistor R6 is used for receiving a first voltage division signal, namely is connected between the first resistor R2 and the second resistor R3. The equidirectional input end of the operational comparator U2 is connected with a fifth resistor R7, the fifth resistor R7 is used for receiving the second voltage division signal, that is, is connected between the third resistor R4 and the anode of the first zener diode ZD1, and the output end of the operational comparator U2 is used for outputting a corresponding comparison signal. A first filter capacitor C1 is connected between the fifth resistor R7 and the third resistor R4, the positive end of the first filter capacitor C1 is connected between the fifth resistor R7 and the third resistor R4, the negative end of the first filter capacitor C1 is connected with the grounding terminal GND1, and the positive end of the first filter capacitor C1 and the positive end of the first voltage stabilizing diode ZD1 are sequentially connected between the fifth resistor R7 and the third resistor R4.
The amplifier sub-module 24 includes a transistor Q1, and in this embodiment, the transistor Q1 is of an s8050 type. The base of the triode Q1 is used for receiving the comparison signal, namely the base of the triode Q1 is connected with the output end of the operation comparator U2, and a sixth resistor R8 for protection is connected in series between the triode Q1 and the operation comparator U2. A seventh resistor R9 is connected to the collector of the triode Q1, and the other end of the seventh resistor R9 is used for connecting to the output end (i.e., + 24V) of the secondary winding 13. The emitter of the transistor Q1 is used for outputting a corresponding amplified signal, and the emitter of the transistor Q1 is the output end of the amplifying submodule 24.
The frequency feedback device also comprises an execution module 3, which is used for receiving the control signal and outputting the execution signal to the frequency feedback module 1 so as to control whether the frequency feedback module 1 is conducted or not. The execution module 3 comprises an optocoupler relay U1, and in the embodiment, the optocoupler relay U1 is in a pc817 model. The frequency feedback module 1 comprises a frequency modulation resistor R1, the frequency modulation resistor R1 is connected with an oscillation resistor R5 in parallel, and the photosensitive resistor end of the optocoupler relay U2 is connected on the frequency modulation resistor R1 in series, so that the frequency modulation resistor R1 and the photosensitive resistor end of the optocoupler relay U2 are connected on the oscillation resistor R5 in parallel. The emitting electrode of the triode Q1 is connected to the anode of the light emitting diode of the optocoupler relay U1, and the cathode of the light emitting diode of the optocoupler relay U1 is connected with the grounding end GND 1.
The implementation principle of the output constant voltage control system of the single-ended flyback switching power supply in the embodiment of the application is as follows: when the output voltage of the secondary winding 13 or the secondary winding 8 expands to the maximum due to the larger inductive load of the single-ended flyback switching power supply, the output voltage suddenly decreases, at this time, the output voltage of the secondary winding 13 flows into the reverse input end of the operational comparator U2 after being divided by the first resistor R2, the second resistor R3 and the fourth resistor R6, the output voltage of the secondary winding 13 flows into the same-direction input end of the operational comparator U2 after being divided by the third resistor R4, the first voltage-stabilizing diode ZD1 and the fifth resistor R7, and the output voltage of the secondary winding 13 decreases, so that the first voltage-stabilizing diode ZD1 is difficult to conduct, at this time, the output voltage of the secondary winding 13 directly flows into the same-direction input end of the operational amplifier U2, and the output voltage of the secondary winding 13 flowing into the reverse input end of the operational amplifier U2 also flows through the second resistor R3, so that the voltage of the same-direction input end of the operational amplifier U2 is greater than the voltage of the reverse input end of the operational amplifier U2, and at this time, the operational amplifier U2 outputs a high level.
The operational amplifier U2 outputs a high level to the base of the triode Q2, so that the collector and the emitter of the triode Q2 are conducted to output the high level to the light emitting diode of the optocoupler relay U1, at the moment, the light emitting diode is conducted to emit light to reduce the resistance of the photosensitive resistor end of the optocoupler relay U1, so that the resistance of the photosensitive resistor end and the frequency modulation resistor R1 which are connected on the oscillating resistor R5 in parallel is reduced, the resistance between the fourth pin RT/CT and the eighth pin VREF of the pulse width modulation chip U3 is reduced, the output frequency of the single-ended flyback switching power supply is improved, namely, the output power is increased, the output voltage of the secondary winding 13 is improved, and the purpose of enabling the single-ended flyback switching power supply to output constant voltage is achieved.
The control mode of pulse width modulation of the pulse width modulation module of the single-ended flyback switching power supply and the control mode of modulation of the frequency feedback module are added, so that the control mode that the single-ended flyback switching power supply has the pulse width modulation and frequency modulation (namely PWM + PFM) closed-loop control at the same time is created, and the purpose of accurately controlling the constant voltage output of the single-ended flyback switching power supply in the inverter welding power supply is achieved.
The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.
Claims (8)
1. The utility model provides a single-ended flyback switching power supply output constant voltage control system which characterized in that, including:
the frequency feedback module (1) is electrically connected with the pulse width modulation module and is used for regulating and controlling the frequency of the pulse width modulation module so as to realize the regulation and control of voltage;
the input end of the control module (2) is connected with the output end of the single-ended flyback switching power supply, compares the received voltage with a threshold voltage and outputs a corresponding control signal;
and the input end of the execution module (3) is used for receiving the control signal, and the output end of the execution module is used for outputting the execution signal to the frequency feedback module (1) so as to control whether the frequency feedback module (1) is conducted or not.
2. The output constant voltage control system of the single-ended flyback switching power supply according to claim 1, wherein the control module (2) comprises:
the input end of the first voltage division submodule (21) is connected with the output end of the single-ended flyback switching power supply, and the first voltage division submodule is used for dividing the input voltage through a resistor and outputting a corresponding first voltage division signal;
the input end of the second voltage division submodule (22) is connected with the output end of the single-ended flyback switching power supply, and is used for dividing the input voltage through a voltage stabilizing diode and outputting a corresponding second voltage division signal;
and the input end of the comparison submodule (23) is used for receiving the first voltage division signal and the second voltage division signal, comparing the first voltage division signal with the second voltage division signal and outputting a corresponding comparison signal.
3. The output constant voltage control system of the single-ended flyback switching power supply according to claim 2, wherein the control module (2) further comprises:
and the input end of the amplification submodule (24) is used for receiving the comparison signal, amplifying the comparison signal and outputting a corresponding amplification signal to the execution module (3), wherein the amplification signal is a control signal.
4. The output constant voltage control system of the single-ended flyback switching power supply of claim 3, wherein: the implementation module (3) is including opto-coupler relay U1, frequency feedback module (1) is including frequency modulation resistance R1, frequency modulation resistance R1 is parallelly connected with the pulse width modulation module, opto-coupler relay U1's photosensitive resistance end is established ties on frequency modulation resistance R1 and is used for controlling whether circuit of frequency modulation resistance R1 switches on, the output of amplifier submodule piece (24) is connected on opto-coupler relay U1 emitting diode's positive pole.
5. The output constant voltage control system of the single-ended flyback switching power supply of claim 2, wherein: the first voltage division submodule (21) comprises a first resistor R2 and a second resistor R3, one end of the first resistor R2 is connected with one end of the second resistor R3, the other end of the first resistor R2 is connected with the output end of the single-ended flyback switching power supply, the other end of the second resistor R3 is connected with the ground end GND1, and a corresponding first voltage division signal is output between the first resistor R2 and the second resistor R3 as the output end.
6. The output constant voltage control system of the single-ended flyback switching power supply of claim 2, wherein: the second voltage division submodule (22) comprises a third resistor R4 and a first voltage stabilizing diode ZD1, one end of the third resistor R4 is connected with the output end of the single-ended flyback switching power supply, the other end of the third resistor R4 is connected with the anode of the first voltage stabilizing diode ZD1, the cathode of the first voltage stabilizing diode ZD1 is connected with a grounding end GND1, and a corresponding second voltage division signal is output as the output end between the third resistor R4 and the anode of the first voltage stabilizing diode ZD 1.
7. The output constant voltage control system of the single-ended flyback switching power supply of claim 2, wherein: the comparison submodule (23) comprises an operation comparator U2, the reverse input end of the operation comparator U2 is used for receiving a first voltage division signal, the homodromous input end of the operation comparator U2 is used for receiving a second voltage division signal, and the output end of the operation comparator U2 is used for outputting a corresponding comparison signal.
8. The output constant voltage control system of the single-ended flyback switching power supply of claim 3, wherein: the amplifying submodule (24) comprises a triode Q1, the base of the triode Q1 is used for receiving comparison signals, the collector of the triode Q1 is used for being connected with the output end of the single-ended flyback switching power supply, the emitter of the triode Q1 is connected with the anode of the light-emitting diode of the optocoupler relay U1, and the cathode of the light-emitting diode of the optocoupler relay U1 is connected with the grounding end GND 1.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116113106A (en) * | 2023-04-04 | 2023-05-12 | 广东东菱电源科技有限公司 | Multipath output auxiliary source standby low-power consumption circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116113106A (en) * | 2023-04-04 | 2023-05-12 | 广东东菱电源科技有限公司 | Multipath output auxiliary source standby low-power consumption circuit |
| CN116113106B (en) * | 2023-04-04 | 2023-06-20 | 广东东菱电源科技有限公司 | Multipath output auxiliary source standby low-power consumption circuit |
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