CN113725819B - Flyback circuit and control method thereof - Google Patents
Flyback circuit and control method thereof Download PDFInfo
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- CN113725819B CN113725819B CN202110599980.1A CN202110599980A CN113725819B CN 113725819 B CN113725819 B CN 113725819B CN 202110599980 A CN202110599980 A CN 202110599980A CN 113725819 B CN113725819 B CN 113725819B
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- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000005070 sampling Methods 0.000 claims abstract description 59
- 230000001276 controlling effect Effects 0.000 claims description 11
- 230000001105 regulatory effect Effects 0.000 claims description 11
- 230000001360 synchronised effect Effects 0.000 claims description 10
- 238000001514 detection method Methods 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 8
- 230000007423 decrease Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
-
- 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
Abstract
The invention provides a flyback circuit and a control method thereof, wherein a first end of a sampling resistor is connected with a main power tube, a second end of the sampling resistor is connected with a system ground end, a reference ground end of a control circuit of the flyback circuit is connected with a common connection end of the sampling resistor and the main power tube, the voltage of the second end of the sampling resistor is a first negative voltage, and bias voltage is superposed on the basis of the first negative voltage to obtain a first voltage; obtaining an output current estimated signal according to the first voltage; and when the output current estimated signal is larger than the first reference voltage, starting the output current overcurrent protection. The invention can flexibly set the overcurrent protection point, is convenient for system parameter design, and can accurately realize overcurrent protection.
Description
Technical Field
The invention relates to the field of power electronics, in particular to a flyback circuit and a control method thereof.
Background
In the prior art, output overcurrent protection methods of an adapter and a charger are generally implemented in a controller of a flyback circuit through an OPP (over power protection). However, the accuracy of the output overcurrent protection is generally poor, especially under different input voltages, the change of the output overcurrent protection point is relatively large, and the output overcurrent protection point under high input voltage is relatively high, and the input voltage is usually required to be added for compensation, but no method is available for achieving good accuracy.
Taking flyback converters as an example in the prior art, the controller adopts a peripheral circuit as shown in fig. 1, samples the peak voltage representing the peak current of the inductor through the CS PIN, and obtains the conducting interval of the secondary diode through the voltage division of the auxiliary winding (as shown in fig. 1VS PIN). And (3) carrying out low-pass filtering on the peak voltage of the secondary side conduction interval in the whole switching period to obtain a signal representing the average output current, and comparing the signal with an internal threshold value to determine whether to respond to OCP protection.
The output overcurrent protection points set by the traditional method are as follows:wherein N is the primary-secondary side turn ratio of the transformer, R CS Is the primary current sampling resistor, vocp is the internal overcurrent protection circuit set threshold. N is determined by the voltage ratio specification of the primary and secondary side power devices under the input voltage and the output voltage, and is not set at will. Vocp is a fixed value set internally by the flyback controller chip. R is R CS =vcs_max/ipk_max, where vcs_max controller internally sets a fixed value, ipk_max is dependent on the power design of the system, also a value determined by relative comparison, so R CS The comparison of the determined values is not preferable. According to the above, the setting of the output overcurrent protection point is relatively inflexible, and none of the devices is flexibleThe live variable may be set, resulting in a limited design in the application.
Disclosure of Invention
The invention aims to provide a flyback circuit capable of flexibly realizing output current overcurrent protection and a control method thereof, and solves the problem that the setting of an output current overcurrent protection point is relatively inflexible in the prior art.
Based on the above object, the present invention provides a flyback circuit, which comprises a control circuit and a primary side main power tube, wherein the control circuit is used for controlling the primary side main power tube, a first end of a sampling resistor is connected with the main power tube, and a second end of the sampling resistor is connected with a system ground end, and the flyback circuit is characterized in that: the reference ground end of the control circuit is connected with the common connection end of the main power tube and the sampling circuit,
the flyback circuit also comprises a first regulating circuit, the first end of the first regulating circuit is connected with the second end of the sampling resistor, the second end of the first regulating circuit is connected with the sampling end of the control circuit, the control circuit flows through the first regulating circuit through bias current, the voltage of the second end of the first regulating circuit is a first voltage,
the control circuit comprises an overcurrent protection circuit, the overcurrent protection circuit receives the first voltage and obtains an output current estimated signal according to the first voltage, and when the output current estimated signal is larger than a first reference voltage, the overcurrent protection circuit outputs an overcurrent protection signal to start output current overcurrent protection.
Optionally, the first adjusting circuit is a first resistor.
Optionally, the overcurrent protection circuit includes:
the detection circuit detects the first voltage and outputs the first voltage to obtain an output signal of the first voltage during the on period of the synchronous rectifying tube of the flyback circuit;
the filter circuit receives the output signal of the detection circuit to obtain the output current estimated signal;
the first input end of the first comparator receives the output current estimated signal, the second input end of the first comparator receives the first reference voltage and outputs an overcurrent protection signal; and when the output current estimated signal is larger than the first reference voltage, the overcurrent protection signal controls the overcurrent protection to be started.
Optionally, the peak current of the primary inductor is controlled by adjusting the resistance ratio of the sampling resistor and the first resistor.
Optionally, the first voltage is adjusted by adjusting the resistance value of the sampling resistor, so as to adjust the output current estimated signal.
Optionally, the bias current is increased stepwise as the feedback signal of the flyback circuit output voltage is increased.
Optionally, the controller further includes a second comparator, a first input end of which receives the first voltage, a second input end of which receives a second reference voltage, and an output end of which outputs a first control signal; when the first voltage is smaller than the second reference voltage, the first control signal controls the main power tube to be turned off.
Optionally, the control circuit further includes a logic processing circuit and a driving circuit, the logic processing circuit receives the overcurrent protection signal, and logic control signals are obtained after logic processing, and the logic control signals drive the switching action of the main power tube through the driving circuit.
The invention also provides a control method of the flyback circuit, wherein the flyback circuit comprises a primary side main power tube, a first end of a sampling resistor is connected with the main power tube, a second end of the sampling resistor is connected with a system ground end, a reference ground end of the control circuit of the flyback circuit is connected with a common connection end of the sampling resistor and the main power tube, the voltage of the second end of the sampling resistor is a first negative voltage, and bias voltage is superposed on the basis of the first negative voltage to obtain a first voltage;
and obtaining an output current estimated signal according to the first voltage, and starting output current overcurrent protection when the output current estimated signal is larger than a first reference voltage.
Optionally, during the conduction period of the secondary rectifying tube, the first voltage is sampled to obtain a first sampling signal, and the first sampling signal during the conduction period of the secondary rectifying tube is subjected to average value processing in the whole switching period to obtain the output current estimated signal.
Optionally, a first resistor is connected between the second end of the sampling resistor and the sampling end of the controller of the flyback circuit, the bias current flows through the first resistor, the voltage on the first resistor is the bias voltage, and the voltage received by the sampling end of the controller is the first voltage.
Optionally, the first voltage is adjusted by adjusting the resistance value of the sampling resistor, so as to adjust the output current estimated signal.
Optionally, the peak current of the primary inductor of the flyback circuit is controlled by adjusting the resistance ratio of the sampling resistor and the first resistor.
Optionally, the bias voltage is adjusted according to a feedback signal of the flyback circuit output voltage.
Optionally, the bias voltage is stepped up as the feedback signal is increased.
Optionally, when the first voltage is smaller than the second reference voltage, the main power tube is controlled to be turned off.
Compared with the prior art, the invention has the following advantages: the invention provides the output overcurrent protection based on the current sampling structure based on the negative voltage, which can flexibly set the output overcurrent protection point, is convenient for system parameter design and can accurately realize the output overcurrent protection.
Drawings
FIG. 1 is a schematic diagram of a flyback circuit in the prior art;
FIG. 2 is a schematic diagram of a flyback circuit according to the present invention;
FIG. 3 is a schematic diagram of an over-current protection circuit according to the present invention;
FIG. 4 is a waveform diagram of the over-current protection circuit of the present invention;
FIG. 5 is a graph of bias current versus output voltage waveforms in accordance with the present invention;
FIG. 6 is a graph of the voltage at the sampling end of the controller and a second reference voltage according to the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to these embodiments only. The invention is intended to cover any alternatives, modifications, equivalents, and variations that fall within the spirit and scope of the invention.
In the following description of preferred embodiments of the invention, specific details are set forth in order to provide a thorough understanding of the invention, and the invention will be fully understood to those skilled in the art without such details.
The invention is more particularly described by way of example in the following paragraphs with reference to the drawings. It should be noted that the drawings are in a simplified form and are not to scale in order to facilitate a clear and concise description of embodiments of the present inventions.
As shown in fig. 2, a schematic diagram of a flyback circuit of the present invention is illustrated, as shown in fig. 2, a primary inductor is connected to a main power tube M0, one end of a sampling resistor Rcs is connected to the main power tube, the other end is connected to a system ground, where the system ground refers to a ground corresponding to a switching system of the flyback circuit, and it can be understood that the ground is a relative value. The reference ground end GND of the flyback circuit controller is connected to the common connection end of the main power tube M0 and the sampling resistor Rcs, the sampling end CS of the controller is connected to the ground end of the sampling resistor Rcs through a first adjusting circuit, and the first adjusting circuit is a first resistor Roffset in this embodiment. The controller generates a bias current Ioffset that flows through a first resistor Roffset to generate a first voltage VCS. The overcurrent protection circuit U101 receives the first voltage VCS, obtains an output current estimation signal according to the first voltage VCS, and determines whether to start the output current overcurrent protection according to the output current estimation signal.
With continued reference to fig. 2, the comparator U201 receives the first voltage VCS and the second reference voltage cs_ref respectively, compares the first voltage VCS and the second reference voltage cs_ref, and controls the main power transistor M0 to be turned off when the first voltage VCS is smaller than the second reference voltage cs_ref. According to a calculation formula of the first voltage:
VCS＝Ioffset*Roffset-IL*Rcs
the minimum VCS is generally 0V, where IL is maximum, and il=ioffset×roffset/Rcs, and the ratio of the values of the first resistor Roffset and the sampling resistor Rcs determines the peak inductor current, where IL is the primary inductor current, because Ioffset is generally determined according to the feedback signal.
Referring to fig. 2, a logic processing circuit U301 receives a comparison signal output by a comparator U201 and an overcurrent protection signal output by an overcurrent protection circuit U101, and obtains a logic control signal after logic processing, and the logic control signal drives a main power tube through a driving circuit U401. The processing logic of the logic processing circuit U301 is that the logic control signal is used to control the main power transistor to be turned on only when the output current does not reach the overcurrent protection point and the inductor current does not reach the peak current reference point.
As shown in fig. 3, a schematic diagram of an overcurrent protection circuit of the present invention is illustrated, which includes a sampling circuit U101, a filter circuit U102 and a comparator U103, wherein during the conduction period of a secondary diode or a synchronous rectifier of a flyback circuit, the detection circuit U101 detects a first voltage VCS, and at other moments, the detection circuit U101 outputs a low-level signal; the output end of the filter circuit U102 is connected with the input end of the detection circuit U101, and the first sampling signal obtained in the on period Tons of the synchronous rectifying tube is used for the whole switching period T SW Carrying out mean value processing to obtain an estimated signal vo_e of the output current; the comparator U103 receives the estimated signal vo_e and the first reference voltage Vocp, compares the estimated signal vo_e and the first reference voltage Vocp, and when the estimated signal vo_e is greater than the first reference voltage Vocp, the output comparison result represents that the output current flows through, and the output overcurrent protection is started, wherein the output overcurrent protection can be that the main power tube M0 is controlled to be turned off through the logic processing circuit, if the main power tube M0 is turned off for a period of time, the estimated signal vo_e is detected to be smaller than the first reference signal, the output overcurrent protection is released, and the switching power supply system enters a normal feedback control state. The interval Tons in which the secondary rectifier diode or synchronous rectifier tube is turned on is obtained by the auxiliary winding voltage division (i.e., VS voltage).
As shown in fig. 4, illustrating waveforms of the overcurrent protection circuit, in conjunction with the schematic circuit diagram of fig. 3, the waveform Vds is a drain-source voltage of the main power tube M0, ip represents a primary inductor current, ip represents a secondary inductor current, CS represents a sampling end voltage, i.e., a first voltage waveform, cs_sample represents a detection waveform of the CS end voltage in a synchronous rectifier tube conduction stage, and a peakThe value is Ipk R CS Wherein Ipk is peak current of secondary inductance, and waveform of estimated signal Io_e of output current is obtained after low-pass filtering.
Through the above circuit scheme, the estimated signal vo_e may represent the output current information of the switching power supply, and since the voltage value of the first voltage is related to the resistance value of the first resistor, adjusting the resistance value of the first resistor may adjust the voltage value of the first voltage, thereby adjusting the magnitude of the estimated signal io_e. The magnitude of the estimated signal Io_e is different, and for the system, as the first reference voltage of the characteristic overcurrent threshold is unchanged, the starting of the overcurrent protection points of the system is different, so that the overcurrent flexible protection of the switching power supply in different occasions is realized.
According to the design scheme of the circuit, the output overcurrent current protection point is as follows: io=Vocp+N/(2 x Rcs), where N is the primary-secondary turn ratio of the transformer, rcs is the sampling resistor of the primary side, vocp is the set threshold of the internal overcurrent protection circuit, and by adopting the current sampling method of the present invention, rcs= (Ioffset_max×Roffset)/Ipk_max, where Ioffset_max is the fixed value inside the controller, ipk_max is determined by the system, and is also a value determined by comparison, the resistance of Rcs can be flexibly adjusted by flexibly adjusting the resistance of Roffset, so that the overcurrent protection point of the output current can be flexibly adjusted.
As shown in fig. 5, the waveform diagram showing the relationship between the bias current and the output voltage is that Ioffset is a given bias current waveform, FB is a feedback voltage waveform representing the output voltage, and the bias current Ioffset is adjusted according to the feedback voltage FB. The offset current Ioffset is increased along with the feedback voltage FB in a step-like manner, so that the problem of the reduction of the working efficiency of the flyback circuit under light load can be effectively solved.
As shown in fig. 6, a graph illustrating the relationship between the voltage of the sampling end of the controller and the second reference voltage is shown, when the primary side main power tube is turned off, the voltage of the sampling end CS of the controller is the largest, which is the product of the offset current Ioffset and the first resistor Roffset, when the primary side main power tube is turned on, the voltage of the sampling end CS of the controller starts to decrease, when the voltage of the sampling end CS decreases to the second reference voltage cs_ref, the main power is controlled to be turned off, and cs_ref generally takes 0V or is a tiny voltage signal. In this embodiment, the second reference voltage characterizes the peak reference current, and the sampling end CS voltage reaches the second reference voltage cs_ref, which is equivalent to the main power tube current reaching the preset peak current, and then the main power tube is controlled to be turned off. The conduction of the main power tube can be controlled according to a clock signal or other conduction control signals. The bias current Ioffset may be adjusted with the feedback voltage FB, with particular reference to fig. 5.
Although the embodiments have been described and illustrated separately above, and with respect to a partially common technique, it will be apparent to those skilled in the art that alternate and integration may be made between embodiments, with reference to one embodiment not explicitly described, and reference may be made to another embodiment described.
The above-described embodiments do not limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the above embodiments should be included in the scope of the present invention.
Claims (14)
1. The utility model provides a flyback circuit, includes the main power tube of control circuit and primary, control circuit is used for controlling primary main power tube, and sampling resistor first end is connected main power tube, sampling resistor second end connection system ground, its characterized in that: the reference ground end of the control circuit is connected with the common connection end of the main power tube and the sampling resistor,
the flyback circuit also comprises a first regulating circuit, the first end of the first regulating circuit is connected with the second end of the sampling resistor, the second end of the first regulating circuit is connected with the sampling end of the control circuit, the control circuit flows through the first regulating circuit through bias current, the voltage of the second end of the first regulating circuit is a first voltage,
the control circuit comprises a second comparator, wherein a first input end of the second comparator receives the first voltage, a second input end of the second comparator receives a second reference voltage, and an output end of the second comparator outputs a first control signal; when the first voltage is smaller than the second reference voltage, the first control signal controls the main power tube to be turned off;
the control circuit comprises an overcurrent protection circuit, the overcurrent protection circuit receives the first voltage during the conduction period of a secondary diode or a synchronous rectifying tube of the flyback circuit, an output current estimated signal is obtained according to the first voltage, and when the output current estimated signal is larger than a first reference voltage, the overcurrent protection circuit outputs an overcurrent protection signal to start the overcurrent protection of the output current.
2. The flyback circuit of claim 1, wherein: the first regulating circuit is a first resistor.
3. Flyback circuit according to claim 1 or 2, characterized in that: the overcurrent protection circuit includes:
the detection circuit detects the first voltage and outputs the first voltage to obtain an output signal of the first voltage during the conduction period of the secondary diode or the synchronous rectifying tube of the flyback circuit;
the filter circuit receives the output signal of the detection circuit to obtain the output current estimated signal;
the first input end of the first comparator receives the output current estimated signal, the second input end of the first comparator receives the first reference voltage and outputs an overcurrent protection signal; and when the output current estimated signal is larger than the first reference voltage, the overcurrent protection signal controls the overcurrent protection to be started.
4. The flyback circuit of claim 2, wherein: and controlling the peak current of the primary inductor by adjusting the resistance ratio of the sampling resistor to the first resistor.
5. The flyback circuit of claim 1, wherein: and adjusting the first voltage by adjusting the resistance value of the sampling resistor, so as to adjust the output current estimated signal.
6. The flyback circuit of claim 1, wherein: the bias current increases stepwise as the feedback signal of the flyback circuit output voltage increases.
7. A flyback circuit according to claim 3, wherein: the control circuit also comprises a logic processing circuit and a driving circuit, wherein the logic processing circuit receives the overcurrent protection signal and obtains a logic control signal after logic processing, and the logic control signal drives the switching action of the main power tube through the driving circuit.
8. The control method of the flyback circuit comprises a primary side main power tube and is characterized in that: the first end of the sampling resistor is connected with the main power tube, the second end of the sampling resistor is connected with the system ground end, the reference ground end of the control circuit of the flyback circuit is connected with the common connection end of the sampling resistor and the main power tube, the voltage of the second end of the sampling resistor is a first negative voltage, and the bias voltage is superposed on the basis of the first negative voltage to obtain a first voltage;
comparing the first voltage with a second reference voltage, and controlling the main power tube to be turned off when the first voltage is smaller than the second reference voltage;
and receiving the first voltage during the conduction period of the secondary diode or the synchronous rectifying tube of the flyback circuit, obtaining an output current estimated signal according to the first voltage, and starting the output current overcurrent protection when the output current estimated signal is larger than a first reference voltage.
9. The method for controlling a flyback circuit according to claim 8, wherein: and during the conduction period of the secondary diode or the synchronous rectifying tube, sampling the first voltage to obtain a first sampling signal, and carrying out average value processing on the first sampling signal during the conduction period of the secondary diode or the synchronous rectifying tube in the whole switching period to obtain the output current estimated signal.
10. The method for controlling a flyback circuit according to claim 8, wherein: and a first resistor is connected between the second end of the sampling resistor and the sampling end of the controller of the flyback circuit, bias current flows through the first resistor, the voltage on the first resistor is the bias voltage, and the voltage received by the sampling end of the controller is the first voltage.
11. The method for controlling a flyback circuit according to claim 8, wherein: and adjusting the first voltage by adjusting the resistance value of the sampling resistor, so as to adjust the output current estimated signal.
12. The method for controlling a flyback circuit according to claim 10, wherein: and controlling the peak current of the primary inductance of the flyback circuit by adjusting the resistance ratio of the sampling resistor and the first resistor.
13. The method for controlling a flyback circuit according to claim 8, wherein: and adjusting the bias voltage according to a feedback signal of the flyback circuit output voltage.
14. The method for controlling a flyback circuit according to claim 8, wherein: the bias voltage is increased stepwise as the feedback signal is increased.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204030996U (en) * | 2014-05-26 | 2014-12-17 | 昂宝电子（上海）有限公司 | A kind of reverse exciting switching voltage regulator circuit |
| CN109067191A (en) * | 2017-12-15 | 2018-12-21 | 杰华特微电子（杭州）有限公司 | Flyback power supply converter and its control method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8488342B2 (en) * | 2008-10-21 | 2013-07-16 | On-Bright Electronics (Shanghai) Co., Ltd. | Systems and methods for constant voltage mode and constant current mode in flyback power converters with primary-side sensing and regulation |
| JP5341627B2 (en) * | 2009-06-11 | 2013-11-13 | パナソニック株式会社 | Semiconductor device and switching power supply device |
| US9793815B2 (en) * | 2015-07-24 | 2017-10-17 | Dell Products L.P. | Over current protection in a variable output power supply |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204030996U (en) * | 2014-05-26 | 2014-12-17 | 昂宝电子（上海）有限公司 | A kind of reverse exciting switching voltage regulator circuit |
| CN109067191A (en) * | 2017-12-15 | 2018-12-21 | 杰华特微电子（杭州）有限公司 | Flyback power supply converter and its control method |
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