CN104319986A - Power supply powering off method and power supply - Google Patents
Power supply powering off method and power supply Download PDFInfo
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- CN104319986A CN104319986A CN201410558203.2A CN201410558203A CN104319986A CN 104319986 A CN104319986 A CN 104319986A CN 201410558203 A CN201410558203 A CN 201410558203A CN 104319986 A CN104319986 A CN 104319986A
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- former limit
- main switch
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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
- H02M1/36—Means for starting or stopping converters
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Abstract
An embodiment of the invention discloses a power supply powering off method which includes receiving a powering off signal, changing the connection time of a primary side main switch of a transformer, or changing the on-off frequency of the primary side main switch; detecting voltage second product of the primary side input voltage in the on-off time or a control value that the voltage second product corresponds to on the secondary side of the transformer, or detecting the on-off frequency of the primary side main switch on the secondary side of the transformer; controlling the on-off state of a synchronous rectifier of the secondary side of the transformer according to the voltage second product, the control value that the voltage second product corresponds to or the on-off frequency of the primary side main switch. The power supply can effectively avoid self oscillation in the powering-off process without additional circuit elements, and is small in circuit area, simple in structure and low in cost.
Description
The application is the divisional application of a patent application, and the applying date of original application is on December 20th, 2012, and application number is that the name of 201210558499.9 original applications is called a kind of power supply closedown method and power supply
Technical field
The present invention relates to field of power supplies, particularly relate to a kind of power supply closedown method and power supply.
Background technology
There is significant odds for effectiveness at low-voltage, high-current field synchronous rectification than the asynchronous rectification of diode, therefore use very extensive in Switching Power Supply.But at former edge-impulse width modulated (Pulse Width Modulation, when PWM) controlling to be applied in isolated DC power supply, the drive singal of secondary synchronous rectification circuit needs to be delivered to secondary from former limit, after the shutdown of former frontier juncture machine control unit, secondary synchronous rectification circuit just loses control.Isolated DC power supply is when using secondary synchronous rectification, and the electric current in outputting inductance can be two-way, and when underloading, outputting inductance electric current can become negative sense.If DC-isolation power supply is when shutting down, the synchronously driven shutoff of secondary is not controlled, then after the machine of former frontier juncture, uncontrollable self-oscillation easily occurs circuit, thus adds circuit element stress.Self-oscillation can continue the long period in some cases, even can be sustained, and impact plays machine next time.Fig. 1 is the oscillogram before and after the shutdown of existing normal shock active clamp DC converter secondary continued flow tube.As shown in Figure 1, when t=550 microsecond, power supply shuts down, and the waveform after shutdown is very intensive, there occurs self-oscillation just because of the circuit of synchronous rectification in power supply.
There is self-oscillatory problem to solve the rear circuit of synchronous rectification of shutdown, on secondary synchronously driven shutoff control loop, usually making to use up occasionally driving transformer in prior art transmit off signal from former limit.Fig. 2 is the existing schematic diagram utilizing optocoupler control circuit to shut down, and as shown in Figure 2, after off signal passes to secondary control circuit by optocoupler or other isolating device, circuit of synchronous rectification turned off by secondary control circuit.But, no matter be transmit off signal with optocoupler or other isolating device, all need extra circuits element in circuit.And the requirement of safety creepage distance to be met due to optocoupler or other isolating device, element area is larger.Each of which increases volume and the cost of circuit.In addition, the shutdown moment of current common former limit PWM shutdown control unit is all random, that is the shutdown moment can occur in any time in a switch periods, so, even if the time of delay of transmitting off signal with optocoupler or other isolating device is short to negligible, electric current during underloading shutdown in secondary outputting inductance may be still reverse, thus secondary synchro switch pipe overvoltage even avalanche breakdown when causing shutdown.
Summary of the invention
Embodiment of the present invention technical problem to be solved is, provides a kind of power supply closedown method and power supply.Effectively self-oscillation can be avoided when shutting down.
First aspect, the embodiment of the present invention provides a kind of power supply closedown method, can comprise: receive off signal, changes the ON time of the former limit main switch of transformer; The voltagesecond product of former limit input voltage in described ON time or controlling value corresponding to described voltagesecond product is detected at the secondary of transformer; The shutoff of the synchronous rectifier of the secondary of described transformer is controlled, to realize power supply shutdown according to described voltagesecond product or controlling value corresponding to described voltagesecond product.
Second aspect, the embodiment of the present invention provides another kind of power supply closedown method, can comprise: receive off signal, changes the switching frequency (or switch periods) of the former limit main switch of transformer; The switching frequency (or switch periods) of described former limit main switch is detected at the secondary of transformer; The shutoff of the synchronous rectifier of the secondary of described transformer is controlled according to the switching frequency (or switch periods) of described former limit main switch.
The third aspect, the embodiment of the present invention provides a kind of power supply, can comprise: shutdown control unit, for receiving off signal, changes the ON time of the former limit main switch of transformer; Controlling value acquiring unit, for detecting the voltagesecond product of former limit input voltage in described ON time or controlling value corresponding to described voltagesecond product at the secondary of transformer; Secondary control unit, for controlling the turn-on and turn-off of the synchronous rectifier of the secondary of described transformer according to described voltagesecond product or controlling value corresponding to described voltagesecond product.
Fourth aspect, the embodiment of the present invention provides another kind of power supply, can comprise: shutdown control unit, for receiving off signal, changes the switching frequency (or switch periods) of the former limit main switch of transformer; Frequency detecting unit (or cycle detection unit), for detecting the switching frequency (or switch periods) of described former limit main switch at the secondary of transformer; Secondary control unit, for controlling the shutoff of the synchronous rectifier of the secondary of described transformer according to the switching frequency (or switch periods) of described former limit main switch.
The power supply closedown method that the visible embodiment of the present invention provides and power supply, by receiving off signal, changing the ON time of the former limit main switch of transformer, or changing the switching frequency of former limit main switch; The voltagesecond product of former limit input voltage in described ON time or controlling value corresponding to described voltagesecond product is detected at the secondary of transformer, or the switching frequency of former limit main switch; According to described voltagesecond product or controlling value corresponding to described voltagesecond product, or the switching frequency of former limit main switch, control the shutoff of the synchronous rectifier of the secondary of described transformer, switching circuit can be adjusted to the state being conducive to most shutting down, then remove according to predetermined optimum shutdown sequential the circuit of synchronous rectification turning off former limit circuit and secondary, thus reach the object effectively avoiding shutdown vibration and shutdown stress.Without the need to increasing new circuit element, thus save volume and the cost of circuit, structure is simple, and cost is low, also improves the reliability and stability of power supply simultaneously.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is the oscillogram before and after the shutdown of existing normal shock active clamp DC converter secondary continued flow tube;
Fig. 2 is the existing schematic diagram utilizing optocoupler control circuit to shut down;
Fig. 3 is the schematic flow sheet of the power supply closedown method that the embodiment of the present invention provides;
Fig. 4 a is the schematic flow sheet of another power supply closedown method that the embodiment of the present invention provides;
Fig. 4 b is the schematic flow sheet of the power supply closedown method again that the embodiment of the present invention provides;
Fig. 5 is the schematic flow sheet of the power supply closedown method again that the embodiment of the present invention provides;
Fig. 6 is the logical construction schematic diagram of the power supply that the embodiment of the present invention provides;
Fig. 7 is a kind of circuit diagram of control unit of shutting down in embodiment of the present invention power supply;
Fig. 8 is the logical construction schematic diagram of another power supply that the embodiment of the present invention provides;
Fig. 9 is the logical construction schematic diagram of the power supply again that the embodiment of the present invention provides;
Figure 10 is the logical construction schematic diagram of the power supply again that the embodiment of the present invention provides;
Figure 11 is the signal timing diagram that the power supply shown in Figure 10 is described;
Figure 12 is the logical construction schematic diagram of the power supply again that the embodiment of the present invention provides;
Figure 13 is the flow chart of the power supply closedown method again provided of the embodiment of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
At this, also it should be noted is that, in order to avoid the present invention fuzzy because of unnecessary details, illustrate only in the accompanying drawings with according to the closely-related apparatus structure of the solution of the present invention, and eliminate other details little with relation of the present invention.
Refer to Fig. 3, be the method flow schematic diagram of a kind of power supply closedown method that the embodiment of the present invention provides, this power supply closedown method can be applied to self-powered synchronous rectified power.As shown in the figure, the method comprises:
S101, reception off signal, change the ON time of the former limit main switch of transformer.
Alternatively, the switch periods of former limit main switch can change and also can not change.
S102, detect the voltagesecond product of former limit input voltage in described ON time or controlling value corresponding to described voltagesecond product at the secondary of transformer.
Alternatively, the controlling value of the correspondence of described voltagesecond product can be magnitude of voltage, also can be current value.
Particularly, select herein voltagesecond product as detected parameters be because according to the input voltage of secondary and ON time can be very easy obtain voltagesecond product parameter, circuit structure is simple, calculate and judge convenient.Certainly, timer conter also can be set in circuit to detect the frequency of pwm signal, cycle, the isoparametric value of pulsewidth using as the reference conditions judging whether to shut down.
S103, control the shutoff of the synchronous rectifier of the secondary of described transformer according to described voltagesecond product or controlling value corresponding to described voltagesecond product.
Visible, the power supply closedown method that the embodiment of the present invention provides is by changing the ON time of former limit main switch, change the voltagesecond product of the input voltage that secondary detects, thus, switching circuit is adjusted to the state being conducive to most shutting down, then remove according to predetermined optimum shutdown sequential the circuit of synchronous rectification turning off former limit circuit and secondary, thus reach the object eliminating shutdown vibration and shutdown stress.Without the need to increasing new circuit element, save volume and the cost of circuit.
Referring to Fig. 4 a, is the schematic flow sheet of the power supply closedown method that the embodiment of the present invention provides.In the present embodiment, said method comprising the steps of:
S201, receives off signal, shortens the ON time of the former limit main switch of transformer.
Particularly, there is the mode of the ON time of the former limit main switch of following several shortening transformer, but be not limited to following several mode: the former limit main switch that can shorten transformer turns off at least one switch periods front, the ON time shortening the switch after switch periods is less than the ON time of the switch before shortening switch periods.Also can chopped pulse width at least one switch periods before the former limit main switch of transformer turns off.The former limit main switch that can also shorten transformer turns off at least one switch periods front, and selects one or more in the switch periods be shortened, chopped pulse width in described one or more switch periods be shortened.
Preferably, can former limit main switch turn off before last cycle in chopped pulse width.Be implemented as the high level of chopped pulse, to realize last ON time before shortening switch OFF.Here pulse can be pwm pulse.
It should be noted that, moment that can turn off at former limit main switch time of various parameter change complete herein, but measures with switch periods, when being beneficial to subsequent detection in units of the cycle statistic mixed-state value.
S202, detects the voltagesecond product of former limit input voltage in described ON time or controlling value corresponding to described voltagesecond product at the secondary of transformer.
The controlling value of the correspondence of voltagesecond product can be magnitude of voltage, also can be current value.
Particularly, select herein voltagesecond product as detected parameters be because according to the input voltage of secondary and ON time can be very easy obtain voltagesecond product parameter, circuit structure is simple, calculate and judge convenient.Certainly, timer conter also can be set in circuit to detect the frequency of pwm signal, cycle, the isoparametric value of pulsewidth using as the reference conditions judging whether to shut down.
S203, when described voltagesecond product or controlling value corresponding to described voltagesecond product are less than or equal to preset value, turns off the synchronous rectifier of secondary.
Particularly, when preset value herein can not shut down with reference to power supply, stable state voltagesecond product when circuit normally works is arranged, and usually can arrange this preset value according to the change trend of switch periods and/or pulse duration and be less than stable state voltagesecond product.
Referring to Fig. 4 b, is the schematic flow sheet of the power supply closedown method that the embodiment of the present invention provides.In the present embodiment, said method comprising the steps of:
S301, receives off signal, lengthens the ON time of the former limit main switch of transformer;
Concrete, there is the mode of the ON time of the former limit main switch of following several lengthening transformer, but be not limited to following several mode: can lengthen at least one switch periods before the former limit main switch shutoff of transformer, the ON time lengthening the switch after switch periods is greater than the ON time of the switch before lengthening switch periods; Or, at least one switch periods before the former limit main switch of transformer turns off, add long pulse width; Or, lengthen at least one switch periods before the former limit main switch shutoff of transformer, from least one switch periods be lengthened out, select one or more switch periods, in described one or more switch periods be lengthened out, add long pulse width.
Preferably, long pulse width can be added in last cycle before former limit main switch turns off.Be implemented as the high level adding long pulse, to realize last ON time before extending switch OFF.Here pulse can be pwm pulse.
It should be noted that, moment that can turn off at former limit main switch time of various parameter change complete herein, but measures with switch periods, when being beneficial to subsequent detection in units of the cycle statistic mixed-state value.
S302, detects the voltagesecond product of former limit input voltage in described ON time or controlling value corresponding to described voltagesecond product at the secondary of transformer;
S303, when described voltagesecond product or controlling value corresponding to described voltagesecond product are more than or equal to preset value, turns off the synchronous rectifier of secondary.
Particularly, preset value herein correspondingly can be set to be greater than stable state voltagesecond product.
Visible, the power supply closedown method that the embodiment of the present invention provides is by utilizing the transmission path of the original pwm signal of circuit or other signal, before being powered off, send one group from former limit and be different from shutdown pulse normal operating condition to secondary, so that secondary circuit detection and Identification, simultaneously, utilize the shutdown pulse that this group is special, switching circuit can be adjusted to the state being conducive to most shutting down, then remove according to predetermined optimum shutdown sequential the circuit of synchronous rectification turning off former limit circuit and secondary, thus reach the object eliminating shutdown vibration and shutdown stress.Without the need to increasing new circuit element, thus save volume and the cost of circuit.And change switch periods and/or change pulse duration and comprehensively constitute diversified pattern, a certain parameter can be changed separately and also can change two parameters simultaneously, only need to guarantee shutdown pulse that former limit sends be different from normal operating condition under pulse.
Refer to Fig. 5, the embodiment of the present invention also provides a kind of power supply closedown method, and the method comprises:
S401, reception off signal, change the switching frequency of the former limit main switch of transformer.
The ON time of switch can extend, and also can remain unchanged, and also can shorten, and is not construed as limiting this embodiment of the present invention.
S402, detect the switching frequency of described former limit main switch at the secondary of transformer;
S403, control the shutoff of the synchronous rectifier of the secondary of described transformer according to the switching frequency of described former limit main switch.
Under a kind of implementation, after receiving off signal, improve the switching frequency of the former limit main switch of transformer.Secondary preserves the preset value of a switching frequency, and this preset value can be set to slightly higher than power supply switching frequency in normal state.Secondary sense switch frequency, compares this switching frequency with described preset value, when the switching frequency that this detects is greater than or equal to this preset value, turns off the synchronous rectifier of secondary.
Under another kind of implementation, after receiving off signal, reduce the switching frequency of the former limit main switch of transformer.Secondary preserves the preset value of a switching frequency, and this preset value can be set to slightly lower than power supply switching frequency in normal state.After secondary sense switch frequency, this switching frequency is compared with described preset value, when the switching frequency that this detects is less than or equal to preset value, turn off the synchronous rectifier of secondary.
Certainly, it will be appreciated by persons skilled in the art that changing switching frequency is equal to change switch periods in fact.The implementation in sense switch frequency or sense switch cycle is all the general knowledge of those skilled in the art, does not repeat them here.In addition, the technical scheme of the change ON time that the embodiment of the present invention provides can realize with the technical scheme changing switching frequency simultaneously, as long as arrange corresponding detection mode and preset value at secondary, just can reach identical object.
Referring to Fig. 6, is a kind of circuit diagram of embodiment of the present invention power supply.Shown in Fig. 6 is semibridge system rectification circuit.It will be appreciated by those skilled in the art that this is only exemplary, and unrestricted the present invention, the present invention also can apply full-bridge type rectification circuit or doubly streaming rectification circuit.In the present embodiment circuit, power supply comprises:
Shutdown control unit 101, for receiving off signal, changes the ON time of the former limit main switch of transformer TX1;
Under a kind of implementation, shutdown control unit 101 is for shortening the ON time of the former limit main switch of transformer.
Particularly, following several implementation is had: the former limit main switch shortening transformer turns off at least one switch periods front; Or, chopped pulse width at least one switch periods before the former limit main switch of transformer turns off; Or the former limit main switch shortening transformer turns off at least one switch periods front, and selects one or more in the switch periods be shortened, chopped pulse width in described one or more switch periods be shortened.
Under another kind of implementation, shutdown control unit 101 is for lengthening the ON time of the former limit main switch of transformer.
Particularly, following several implementation is had: lengthen at least one switch periods before the former limit main switch shutoff of transformer; Or, at least one switch periods before the former limit main switch of transformer turns off, add long pulse width; Or, lengthen at least one switch periods before the former limit main switch shutoff of transformer, from least one switch periods be lengthened out, select one or more switch periods, in described one or more switch periods be lengthened out, add long pulse width.
Controlling value acquiring unit 102, described controlling value acquiring unit is configured to obtain voltagesecond product with the former limit input voltage of described transformer in described ON time or the corresponding controlling value of voltagesecond product;
Under a kind of implementation, controlling value acquiring unit 102 detects the corresponding controlling value of the voltagesecond product of former limit input voltage vin s in described ON time at transformer TX1 secondary; Under other implementation, timer conter can be set in circuit to detect the frequency of pwm signal, cycle, the isoparametric value of pulsewidth using as the reference conditions judging whether to shut down.
Secondary control unit 103, for the turn-on and turn-off of the synchronous rectifier of the secondary according to described voltagesecond product or controlling value control transformer TX1 corresponding to described voltagesecond product.
Under a kind of implementation, when described voltagesecond product or controlling value corresponding to described voltagesecond product are less than or equal to preset value, turn off the synchronous rectifier of secondary, to realize power supply shutdown.
Such as, shutdown control unit 101 shortens at least one switch periods before the former limit main switch Q1 shutoff of transformer TX1, the described voltagesecond product that controlling value acquiring unit 102 detects or controlling value corresponding to described voltagesecond product are less than or equal to preset value, now secondary control unit 103 closes the circuit of synchronous rectification of secondary, completes shutdown.
Again such as, when shutdown control unit 101 lengthens at least one switch periods before the former limit main switch Q1 shutoff of transformer TX1, the described voltagesecond product that controlling value acquiring unit 102 detects or controlling value corresponding to described voltagesecond product are more than or equal to preset value, now secondary control unit 103 closes the circuit of synchronous rectification of secondary, completes shutdown.
As shown in Figure 6, this power circuit also comprises: modulation signal generator 104, transformer TX1, former limit main switch Q1, the first secondary-side switch Q2, the second secondary-side switch Q3 and LC filter; Switch Q1, Q2 and Q3 can be metal-oxide-semiconductor or other active switch.
Described modulation signal generator 104 is electrically connected with described shutdown control unit 101, for modulating former limit input voltage vin; Wherein, modulation signal generator 104 can be pulse width modulating signal generator, also can be pulse frequency modulated signal generator.
Described shutdown control unit 101 is electrically connected with described former limit main switch Q1; Described former limit main switch Q1 is for controlling the closed circuit and open circuit of former limit circuit loop.
Main switch Q1 one end, described former limit meets former limit Input voltage terminal Vin by the primary coil P1 of described transformer TX1, other end ground connection;
Described controlling value acquiring unit 102 is connected between secondary voltage input Vins and described secondary control unit;
Described secondary control unit 103 is connected with described first secondary-side switch Q2 and the second secondary-side switch Q3;
Described first secondary-side switch Q2 and the second secondary-side switch Q3 is connected with described LC filter;
Wherein, described former limit main switch Q1, the first secondary-side switch Q2 and the second secondary-side switch Q3 are isolated gate FET.Certainly, also can be other suitable switching devices.
In the present embodiment, preferably, isolated gate FET is adopted to be described as switch.
As shown in Figure 6, LC filter circuit comprises an an outputting inductance L1 and filter capacitor C1.The one termination secondary voltage input Vins of outputting inductance L1, another termination output voltage terminal Vo, output voltage terminal Vo are by filter capacitor C1 ground connection.The source ground of former limit main switch Q1, grid connects shutdown control unit 101, and draining meets original edge voltage input Vin by primary coil P1.The source ground of the first secondary-side switch Q2, grid connects secondary control unit 103, drains to meet secondary Input voltage terminal Vins by secondary coil S1.The source ground of the second secondary-side switch Q3, grid connects secondary control unit 103, drains to meet output voltage terminal Vo by outputting inductance L1.
When needs shut down, shutdown control unit 101 receives off signal, and changes switch periods and/or change pulse duration at least one cycle as required before the former limit main switch Q1 of transformer TX1 turns off.Here, we select chopped pulse width to be described.Because shorten pulse duration, therefore the ON time Ton of former limit main switch Q1 will shorten.In the ON time Ton shortened, former limit input voltage vin continues to induce secondary input voltage vin s at secondary, controlling value acquiring unit 102 receives secondary input voltage vin s, and calculate and the voltagesecond product of secondary input voltage vin s in ON time Ton, namely calculate the former limit input voltage vin voltagesecond product among this ON time Tons proportional with secondary input voltage vin s.Controlling value acquiring unit 102 can directly judge according to voltagesecond product, also can carry out corresponding calculating and voltagesecond product controlling value one to one according to voltagesecond product.In the present embodiment, controlling value acquiring unit 102 exports the controlling value Vvs corresponding with the former limit voltagesecond product of input voltage vin in ON time Ton., it should be noted that, this controlling value Vvs can be magnitude of voltage as shown in Figure 6 herein, and certainly, according to the design needs of circuit, this controlling value also can be current value.In the present embodiment, because shutdown control unit 101 shortens pulse duration, therefore the ON time Ton of former limit main switch Q1 reduces, and therefore the voltagesecond product of secondary input voltage vin s in ON time Ton reduces, and then the controlling value Vvs of correspondence reduces.Secondary control unit 103 detection control value Vvs, when voltagesecond product is less than or equal to preset value, the controlling value of its correspondence is also less than or equal to certain preset value, triggering secondary control unit 103 sends control command and is turned off by the first secondary-side switch Q2 and the second secondary-side switch Q3, thus making the loop open circuit of circuit of synchronous rectification, power supply thoroughly shuts down.
It should be noted that, when power supply is when normally working, the voltagesecond product of former limit input voltage vin in ON time Ton keeps a fixed value substantially, this fixed value and output voltage Vo proportional.In the present embodiment, voltagesecond product when normally being worked by power supply becomes stable state voltagesecond product.When arranging described preset value, can arrange according to stable state voltagesecond product.In the present embodiment, it is less than the corresponding controlling value of stable state voltagesecond product that preset value can be set.When power supply normally works, former limit does not send off signal, the shutdown loop of control unit 101 to former limit circuit is inoperative, the ON time of former limit main switch Q1 keeps normal condition, at this moment, the voltagesecond product of former limit input voltage vin in ON time Ton is stable state voltagesecond product, and secondary control unit 103 detects that controlling value is at this moment larger than preset value, the closed circuit or open circuit in normal control synchronization rectification circuit loop.When shutting down to power supply, former limit sends off signal, shutdown control unit receives off signal, chopped pulse width, the ON time Ton of former limit main switch Q1 reduces, thus the former limit voltagesecond product of input voltage vin in this ON time Ton is reduced to less than preset value, so secondary control unit 103 no longer carries out normal control operation to circuit of synchronous rectification, but directly send instruction and control the first secondary-side switch Q2 and the second secondary-side switch Q3 and turn off, make circuit of synchronous rectification open circuit, power supply thoroughly shuts down.
Accordingly, when shortening switch periods (namely increasing switching frequency) or shorten switch periods and pulse duration simultaneously, situation is described above;
When extending switch periods or extend switch periods and pulse duration simultaneously, the ON time Ton of former limit main switch Q1 will extend, the voltagesecond product of secondary input voltage vin s in ON time Ton increases, controlling value Vvs increases, when voltagesecond product is more than or equal to preset value, secondary control unit 103 sends instruction and controls the first secondary-side switch Q2 and the second secondary-side switch Q3 and turn off, make circuit of synchronous rectification open circuit, power supply thoroughly shuts down.Now, preset value is larger than the controlling value corresponding with stable state voltagesecond product.When power supply normally works, former limit does not send off signal, shutdown control unit 101 is inoperative to former limit circuit loop, the ON time Ton of main switch Q1 keeps normal condition, at this moment the voltagesecond product of former limit input voltage vin in ON time Ton is stable state voltagesecond product, secondary control unit 103 detects that controlling value is at this moment less than predetermined value, the closed circuit or open circuit in normal control synchronization rectification circuit loop.As mentioned above, when shutting down to power supply, former limit sends off signal, the ON time of main switch, in response to off signal, deliberately increases by shutdown control unit, thus the voltagesecond product of former limit input voltage in this ON time increases, controlling value Vvs increases to larger than predetermined value, so secondary control unit no longer carries out normal control operation to circuit of synchronous rectification, but give an order circuit of synchronous rectification open circuit, power supply thoroughly shuts down.
Certainly, also may there is the situation that switch periods is contrary with pulse duration two Parameters variation, at this time only need to determine which parameter dominate, concrete control procedure is shown in foregoing description, repeats no more.
By power supply provided by the invention, effectively can avoid the self-oscillation produced during power cutoff, and without the need to adding new circuit element, therefore circuit area is little, structure is simple, and cost is low, also improves the reliability and stability of power supply simultaneously.
Referring to Fig. 7, is a kind of circuit diagram of the control unit that shuts down in embodiment of the present invention power supply.
The transmission method of this shutdown information provided by the invention is in the realization of PWM controller, and digital P WM controls to control to have more simple advantage than analog PWM.In digital P WM controls, because the pwm pulse width before shutdown and cycle information are all known, and can be stored in controller, so the shutdown pulse train of more complicated optimization can be developed easily.In analog PWM controls, realize the shutdown pulse train of more complicated optimization with analog circuit, then difficulty is relatively large, so will simplify and optimize shutdown pulse train as far as possible.
In the present embodiment, described shutdown control unit comprises RC series circuit, weber clamper comparator Volt-Second Clam and shutdown pulse comparator Shutdown Pulse PWM.
Described RC series circuit is connected between former limit Input voltage terminal Vin and ground;
Between the resistance Rvsc that the in-phase input end of described weber clamper comparator Volt-Second Clam and shutdown pulse comparator Shutdown Pulse PWM is connected to described RC circuit jointly by weber clamper pin VSCLAMP and electric capacity Cvsc, and the threshold value of described weber clamper comparator Volt-Second Clam and shutdown pulse comparator Shutdown Pulse PWM is different.
Shut down on control unit at former limit PWM, an external RC circuit can be adopted to receive in the input voltage VIN of former limit, the weber clamper pin VSCLAMP of shutdown control unit produces the ramp voltage that a slope is proportional to former limit input voltage VIN.When circuit normally works, the peak value of this ramp voltage is fed control loop or weber clamper comparator Volt-Second Clam and controls on a lower level, needing this ramp voltage of last cycle of shutdown to be allowed to rise to a higher level, producing by shutdown pulse comparator Shutdown Pulse PWM the shutdown broad pulse that a voltagesecond product strengthens.
As shown in Figure 7, the threshold value of the pulse comparator Shutdown Pulse PWM that now shuts down is 3V, and the threshold value of weber clamper comparator Volt-Second Clam is 2.5V.Ramp voltage when normal work on VSCLAMP pin is limited by weber clamper comparator Volt-Second Clam, and general crest voltage is operated in about 1.5V-2V.Last lengthens shutdown pulse and is produced by the pulse comparator Shutdown Pulse PWM that shuts down, then the shutdown pulse duration produced is 1.5-2 times of normal working pulse.Shutdown pulse duration is likely long than a normal switch cycles.The length of shutdown broad pulse that last voltagesecond product strengthens can't help control loop and weber clamp circuit determine, but by weber clamper pin VSCLAMP voltage through shutdown pulse comparator Shutdown Pulse PWM and 3V threshold level relatively after determine.
Certainly, the detection of secondary controlling value acquiring unit also can be based on voltagesecond product Cleaning Principle equally, just can realize with a simple RC circuit and a voltage comparator.
It should be noted that, principle of the present invention is applicable to the shutdown information transmission across isolating interface in all isolation class power supplys, comprises DC/DC, the class isolated converters such as AC/DC, DC/AC, AC/AC.
Certainly, principle of the present invention is applicable to PWM too and shuts down control unit at secondary, transmits the application of shutdown information to former limit from secondary; And principle of the present invention is applicable to analog control and digital control.It is more convenient for realizing optimum shutdown pwm pulse sequence with digital control in essence.
Refer to Fig. 8, for the present invention executes the circuit diagram of another power supply that example provides.
In the present embodiment, another form of implementation of shutdown control unit 101 is particularly illustrated.Shutdown control unit 101 comprises control switch 1011, driver element 1012, charge/discharge unit 1013, comparator 1014 and logical block 1015.Control switch 1011 is connected between the output of modulation signal generator 104 and the input of driver element 1012, and closes in response to the control signal coming from logical block 1015 or disconnect.Driver element 1012 is configured to the modulation signal receiving modulation signal generator 104 via control switch 1011, and exports the control terminal of modulation signal to former limit main switch Q1.Between the control terminal that charge/discharge unit 1013 is connected former limit main switch Q1 and ground, for charging according to the ON time of former limit main switch Q1, and the output valve corresponding with charging effect is flowed to comparator 1014.Comparator 1014 is configured to the output valve receiving charge/discharge unit 1013, output valve and reference value are compared, and on the one hand comparative result is exported to modulation signal generator 104 to control the work of modulation signal generator 104, make when the output valve of charge/discharge unit 1013 is greater than reference value, turn off modulation signal generator 104, on the other hand comparative result is exported to logical block 1015.Logical block 1015 is configured to according to off signal, the output of comparator 1014, and the signal of the input of driver element 1012 exports control signal, make when off signal shows to want power cutoff, disconnect control switch 1011, and when making to disconnect control switch 1011, the input of driver element 1012 has high level, to charge to charge/discharge unit 1013, and when the output valve of charge/discharge unit 1013 is greater than reference value, connect control switch 1011, make that the input of driver element 1012 has low level, to turn off former limit main switch.It can thus be appreciated that, when shutting down to power supply, former limit sends off signal, shutdown control unit 101 is in response to off signal, control switch 1011 is disconnected, charge/discharge unit 1013 is charged, and make the charging interval at this moment longer than the charging interval under power supply normal condition, when the output valve corresponding with charging effect is greater than reference value, control switch 1011 is connected, at this moment the modulation signal that the input of driver element 1012 is turned off pulls into low level, and former limit main switch Q1 is turned off, thus the ON time Ton of main switch Q1 increases.According to an example of the present invention, reference value Vref can be set according to the design parameter of circuit, make the output valve that charge-discharge circuit 1013 exports when power supply normally works be less than reference value Vref, and the output valve that charge-discharge circuit 1013 exports when power supply will shut down can be greater than reference value Vref.As mentioned above, when shutting down to power supply, former limit sends off signal, the ON time of main switch, in response to off signal, is deliberately increased by charge/discharge unit 1013 by shutdown control unit 101, thus the voltagesecond product of former limit input voltage in this ON time increases, controlling value Vvs increases to larger than predetermined value, so secondary control unit no longer carries out normal control operation to circuit of synchronous rectification, but give an order circuit of synchronous rectification open circuit, power supply thoroughly shuts down.
Similarly, by the power supply according to the embodiment of the present invention, effectively can avoid self-oscillation by power cutoff, and due to without the need to using optocoupler device, therefore area is little, cost-saving, structure is simple, easy for installation.
In embodiment shown in Fig. 9, particularly illustrate controlling value acquiring unit 102 and can comprise charging circuit 1021 and discharge circuit 1022.Discharge circuit 1022 discharges to charging circuit 1021 when the ON time of main switching control starts, charging circuit 1021 charges in ON time Ton afterwards, and at the end of ON time Ton using the magnitude of voltage corresponding with charging effect as described controlling value Vvs.Therefore, controlling value acquiring unit 102 obtains the controlling value Vvs corresponding with the integrated value of input voltage vin s to the time, and exports controlling value Vvs to secondary control unit 103.The power supply shutdown principle of the present embodiment is substantially identical with the power supply of embodiment noted earlier principle of shutting down, and does not repeat them here.
In embodiment shown in Figure 10, particularly illustrate a form of implementation of shutdown control unit and controlling value acquiring unit.In the present embodiment, modulation signal generator 104 is PWM modulation signal generators, but it will be appreciated by those skilled in the art that, according to different application demands, also PFM (Pulse frequency modulation can be used in the present embodiment,, pulse frequency modulated) and modulation signal generator.Shutdown control unit 101 comprise be made up of resistance R3 and capacitor C4 and diode charge-discharge circuit, comparator U2, with door U1, control switch k1 and driver element U4, wherein between R3 and the C4 control terminal that is connected on former limit main switch Q1 and ground, and D1 is connected across R3 two ends, for discharging to C4.When power supply normally works, off signal is low level, then with door U1 output low level, control switch k1 closes, and pwm signal is transferred into driver element to drive former limit main switch Q1 by switch k1.When off signal is high level, and PWM modulation signal and U2 are when being also high level, then export high level with door U1, control switch k1 disconnects, and the input of driver element U4 keeps high level, exports and also keeps high level, until the voltage of C4 is charged to higher than Vref, comparator U2 is inverted to low level, then with door again output low level, switch k1 close.Meanwhile, because comparator U2 is inverted to low level, quit work by this change notification PWM modulation signal generator, thus PWM modulation signal becomes low level, the input of driver element U4 is pulled into low level by PWM modulation signal, and former limit main switch Q1 is turned off.Extend from the off signal ON time Ton. be namely extended during this period of time that to be high level turn off to former limit main switch Q1 and how long determined by the time constant of charge-discharge circuit R3C4.Diode D1 is used for discharging to capacitor C4.Capacitor C4 is ceaselessly charged or discharged, and can form the sawtooth waveforms of one-period.During normal work, the amplitude of sawtooth waveforms is not high, and during shutdown, amplitude just can significantly increase.
In the present embodiment, charging circuit 1021 in controlling value acquiring unit 102 comprises the first capacitor C2 and the first resistance R1 of series connection, and discharge circuit 1022 comprises the second capacitor C3 and the second resistance R2 of series connection, the branch road at C3 and R2 place and the branch circuit parallel connection at R1 and C2 place, and C3 and R2 is connected on the control end of switch Q4, switch Q4 is connected across C2 two ends, discharges to C2 for during conducting.
In the present embodiment, during the ON time Ton of PWM modulation signal, secondary winding S1 induces a secondary input voltage vin s proportional with former limit input voltage vin, when voltage Vins is in rising edge, the differential circuit formed by electric capacity C3 and resistance R2 is to the very narrow pulsed drive of switch Q4 mono-, make Q4 open in a flash, the electric charge of the first capacitor C2 is bled off, and voltage moves 0V to.During ON time Ton, charge to the first capacitor C2 by the first resistance R1, do not recharge at the end of Ton, now namely the size of the voltage Vvs of the first capacitor C2 represents the integration to time of Vin in the Ton period, is called for short voltagesecond product.By the time next ON time Ton, controlling value acquiring unit 402 again discharges and again charges, and so goes round and begins again.When power supply normally works, Vin keeps a fixed value substantially at the integration to the time of Ton period and voltagesecond product, and when shutting down, because ON time Ton is deliberately enlarged markedly, then voltagesecond product also enlarges markedly, and controlling value Vvs enlarges markedly.After secondary control unit 103 detects the Vvs enlarged markedly, give an order switch Q2 and Q3 turned off on circuit of synchronous rectification, and power supply thoroughly shuts down, and prevents electric current to pour in down a chimney, inhibits self-oscillation.In the present embodiment, the input of two drive singal (be used for driving switch Q2 and Q3) of secondary control unit 103 is from secondary winding S2 and S3 of transformer.
Figure 11 is the signal timing diagram that the self-powered synchronous rectified power shown in Figure 10 is described.
Figure 11 shows the sequential chart of the controlling value Vvs that the voltage Vg1 of the control terminal of main switching control Q1, voltage Vg2 and Vg3 of control terminal of switch Q2 and Q3 of the circuit of synchronous rectification of secondary and controlling value acquiring unit 102 export.See Figure 11, last ON time Ton (Vg1 is last period of high level) of former limit main switch Q1 is longer than ON time above, this is because shutdown control unit 101 increases ON time Ton in response to off signal during shutdown.As can be seen from Figure 11, in the ON time Ton increased, the controlling value Vvs that controlling value acquiring unit 102 exports is increased to larger than the controlling value Vvs under normal condition, exceedes predetermined value.At the ON time Ton increased (namely, Vg1 is last period of high level) after, Vg1 becomes 0, thus main switch Q1 turns off, and controlling value Vvs exceedes predetermined value, so secondary control unit 103 detects the Vvs enlarged markedly, control of giving an order turns off the level of the control terminal of switch Q2 and Q3 on circuit of synchronous rectification, turned off by switch Q2 and Q3, power supply thoroughly shuts down, and does not occur self-oscillation phenomenon.
In the scheme of the embodiment of the present invention, off signal can comprise when being not limited to the off signal because the action triggers such as remote power-off, overcurrent protection, overvoltage protection, overheat protector, under-voltage protection produce.
Refer to Figure 12, for the embodiment of the present invention also provides another kind of power supply, this power supply comprises:
Shutdown control unit 11, for receiving off signal, changes the switching frequency of the former limit main switch of transformer;
The ON time of switch can extend, and also can remain unchanged, and also can shorten, and is not construed as limiting this embodiment of the present invention.
Frequency detecting unit 12, for detecting the switching frequency of described former limit main switch at the secondary of transformer;
Secondary control unit 13, for controlling the shutoff of the synchronous rectifier of the secondary of described transformer according to the switching frequency of described former limit main switch.
Under a kind of implementation, shutdown control unit 11 is specifically for improving the switching frequency of the former limit main switch of transformer; Secondary control unit 13 specifically for: when the switching frequency of described former limit main switch is greater than or equal to preset value, turn off the synchronous rectifier of secondary.
Under another kind of implementation, shutdown control unit 11 is specifically for the switching frequency of former limit main switch reducing transformer; Secondary control unit 13 specifically for: when the switching frequency of described former limit main switch is less than or equal to preset value, turn off the synchronous rectifier of secondary.
Specific implementation can with reference to the embodiment of the method for correspondence.It will be appreciated by persons skilled in the art that changing switching frequency is equal to change switch periods in fact.The implementation in sense switch frequency or sense switch cycle is all the general knowledge of those skilled in the art, and namely frequency detecting unit 12 also can do cycle detection as being used for, and correspondingly, preset value is set to the value of the switch periods under corresponding power normal condition.The means of frequency detecting and cycle detection are varied, and those skilled in the art can select according to demand voluntarily.
Figure 13 is the flow chart to the method that self-device synchronous rectification power supply shuts down according to an embodiment of the invention.
See Figure 13, when shutting down to self-device synchronous rectification power supply, perform shutdown according to following steps.
In step S11, former limit sends off signal, increases last ON time of former limit main switch on former limit; In step S12, detect the voltagesecond product of former limit input voltage in described ON time at secondary; In step S13, when described voltagesecond product is more than or equal to predetermined value, then close the circuit of synchronous rectification of secondary, to shut down to described power supply.
By the description of above-described embodiment, the present invention has the following advantages:
Utilize the transmission path of the original pwm signal of circuit or other signal, before being powered off, send one group from former limit and be different from shutdown pulse normal operating condition to secondary, or change the frequency of former limit switching tube, so that secondary circuit detection and Identification, thus realize switching circuit to adjust to the state being conducive to most shutting down, then remove according to predetermined optimum shutdown sequential the circuit of synchronous rectification turning off former limit circuit and secondary, thus reach the object eliminating shutdown vibration and shutdown stress.Without the need to increasing new circuit element, thus save volume and the cost of circuit, structure is simple, cost is low, also improves the reliability and stability of power supply simultaneously.And change switching frequency and change pulse duration comprehensively constitute diversified pattern, a certain parameter can be changed separately and also can change two parameters simultaneously, only need to guarantee relevant parameter (such as voltagesecond product or switch periods etc.) that secondary detects be different from normal operating condition under this parameter.
One of ordinary skill in the art will appreciate that all or part of flow process realized in above-described embodiment method, that the hardware that can carry out instruction relevant by computer program has come, described program can be stored in a computer read/write memory medium, this program, when performing, can comprise the flow process of the embodiment as above-mentioned each side method.Wherein, described storage medium can be magnetic disc, CD, read-only store-memory body (Read-Only Memory, ROM) or random store-memory body (Random Access Memory, RAM) etc.
Above disclosedly be only present pre-ferred embodiments, certainly can not limit the interest field of the present invention with this, therefore according to the equivalent variations that the claims in the present invention are done, still belong to the scope that the present invention is contained.
Claims (6)
1. a power supply closedown method, is characterized in that, described method comprises:
Receive off signal, change the switching frequency of the former limit main switch of transformer;
The switching frequency of described former limit main switch is detected at the secondary of transformer;
The shutoff of the synchronous rectifier of the secondary of described transformer is controlled according to the switching frequency of described former limit main switch.
2. method according to claim 1, is characterized in that, the switching frequency of the former limit main switch of described change transformer, specifically comprises:
Improve the switching frequency of the former limit main switch of transformer;
The described switching frequency according to described former limit main switch controls the shutoff of the synchronous rectifier of the secondary of described transformer, specifically comprises:
When the switching frequency of described former limit main switch is greater than or equal to preset value, turn off the synchronous rectifier of secondary.
3. method according to claim 1, is characterized in that, the switching frequency of the former limit main switch of described change transformer, specifically comprises:
Reduce the switching frequency of the former limit main switch of transformer;
The described switching frequency according to described former limit main switch controls the shutoff of the synchronous rectifier of the secondary of described transformer, specifically comprises:
When the switching frequency of described former limit main switch is less than or equal to preset value, turn off the synchronous rectifier of secondary.
4. a power supply, is characterized in that, described power supply comprises:
Shutdown control unit, for receiving off signal, changes the switching frequency of the former limit main switch of transformer;
Frequency detecting unit, for detecting the switching frequency of described former limit main switch at the secondary of transformer;
Secondary control unit, for controlling the shutoff of the synchronous rectifier of the secondary of described transformer according to the switching frequency of described former limit main switch.
5. power supply according to claim 4, is characterized in that, described shutdown control unit is specifically for the switching frequency of former limit main switch that improves transformer;
Described secondary control unit specifically for: when the switching frequency of described former limit main switch is greater than or equal to preset value, turn off the synchronous rectifier of secondary.
6. power supply according to claim 1, is characterized in that, described shutdown control unit is specifically for the switching frequency of former limit main switch that reduces transformer;
Described secondary control unit specifically for: when the switching frequency of described former limit main switch is less than or equal to preset value, turn off the synchronous rectifier of secondary.
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| CN2011104323713A CN102437725A (en) | 2011-12-21 | 2011-12-21 | Self-driven synchronous rectification power supply and switching-off method thereof |
| CN201410558203.2A CN104319986A (en) | 2011-12-21 | 2012-12-20 | Power supply powering off method and power supply |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113472203A (en) * | 2020-03-31 | 2021-10-01 | 广州汽车集团股份有限公司 | Synchronous rectification protection method and circuit for DC/DC converter of electric vehicle |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102437725A (en) * | 2011-12-21 | 2012-05-02 | 华为技术有限公司 | Self-driven synchronous rectification power supply and switching-off method thereof |
| CN104716845A (en) * | 2013-12-13 | 2015-06-17 | 上海普锐马电子有限公司 | Cyclic wave falling generator with over-current protection function |
| CN105490548B (en) * | 2014-09-15 | 2018-07-03 | Tdk株式会社 | Switching power unit |
| CN104502677A (en) * | 2014-11-17 | 2015-04-08 | 华为技术有限公司 | Method and device used for detecting voltage change |
| EP3068022B1 (en) | 2015-03-13 | 2019-03-06 | Nxp B.V. | Discharging an input capacitor of a switch mode power supply |
| CN105703642A (en) * | 2016-03-11 | 2016-06-22 | 广州金升阳科技有限公司 | Synchronous rectifier control circuit, method and switching power supply provided with same |
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| WO2019057203A1 (en) | 2017-09-25 | 2019-03-28 | Huawei Technologies Co., Ltd. | Power supply system with reduced bulk capacitance |
| CN109193599A (en) * | 2018-11-02 | 2019-01-11 | 李振奎 | A kind of ladder cuts unrestrained arc-suppressing method and extinguisher |
| US11075585B2 (en) | 2019-01-24 | 2021-07-27 | Hisense Visual Technology Co., Ltd. | Synchronous rectification circuit and display device |
| CN111478566B (en) * | 2019-01-24 | 2022-12-13 | 海信视像科技股份有限公司 | Synchronous rectification circuit and display device |
| TWI701895B (en) * | 2020-04-22 | 2020-08-11 | 產晶積體電路股份有限公司 | Time parameter control method |
| CN111865095B (en) * | 2020-08-27 | 2024-06-18 | 上海新进芯微电子有限公司 | Synchronous rectification control circuit and flyback switching power supply |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1521929A (en) * | 2003-01-20 | 2004-08-18 | 达方电子股份有限公司 | Flyback type conversion device having synchronous rectifier |
| US20080192517A1 (en) * | 2007-02-12 | 2008-08-14 | Spi Electronic Co., Ltd. | Self-excitation synchronous rectification driver |
| CN201238265Y (en) * | 2008-07-24 | 2009-05-13 | 全汉企业股份有限公司 | Flyback type circuit with synchronous control function |
| CN101651426A (en) * | 2009-09-10 | 2010-02-17 | 广州金升阳科技有限公司 | Self-starting control power converter of output terminal |
| US20110305043A1 (en) * | 2010-06-11 | 2011-12-15 | Murata Manufacturing Co., Ltd. | Isolated switching power supply apparatus |
| CN102437725A (en) * | 2011-12-21 | 2012-05-02 | 华为技术有限公司 | Self-driven synchronous rectification power supply and switching-off method thereof |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7459804B2 (en) * | 2004-02-10 | 2008-12-02 | Liebert Corporation | Static transfer switch device and method |
| CN101141096B (en) * | 2007-08-30 | 2011-12-28 | 艾默生网络能源有限公司 | Bridge type closedown detection circuit |
| CN201336631Y (en) * | 2008-12-31 | 2009-10-28 | 瑞谷科技(深圳)有限公司 | Time-delay shutdown circuit of power supply |
| CN101615902B (en) * | 2009-07-16 | 2011-12-28 | 艾默生网络能源有限公司 | Soft-off circuit and method |
| CN202068329U (en) * | 2011-04-22 | 2011-12-07 | 威海东兴电子有限公司 | Multipath output normal-shock power module with fixed voltage second product and no feedback |
-
2011
- 2011-12-21 CN CN2011104323713A patent/CN102437725A/en active Pending
-
2012
- 2012-12-20 CN CN201410558203.2A patent/CN104319986A/en active Pending
- 2012-12-20 CN CN201210558499.9A patent/CN103066825B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1521929A (en) * | 2003-01-20 | 2004-08-18 | 达方电子股份有限公司 | Flyback type conversion device having synchronous rectifier |
| US20080192517A1 (en) * | 2007-02-12 | 2008-08-14 | Spi Electronic Co., Ltd. | Self-excitation synchronous rectification driver |
| CN201238265Y (en) * | 2008-07-24 | 2009-05-13 | 全汉企业股份有限公司 | Flyback type circuit with synchronous control function |
| CN101651426A (en) * | 2009-09-10 | 2010-02-17 | 广州金升阳科技有限公司 | Self-starting control power converter of output terminal |
| US20110305043A1 (en) * | 2010-06-11 | 2011-12-15 | Murata Manufacturing Co., Ltd. | Isolated switching power supply apparatus |
| CN102437725A (en) * | 2011-12-21 | 2012-05-02 | 华为技术有限公司 | Self-driven synchronous rectification power supply and switching-off method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113472203A (en) * | 2020-03-31 | 2021-10-01 | 广州汽车集团股份有限公司 | Synchronous rectification protection method and circuit for DC/DC converter of electric vehicle |
| CN113472203B (en) * | 2020-03-31 | 2023-01-06 | 广汽埃安新能源汽车有限公司 | Synchronous rectification protection method and circuit for DC/DC converter of electric vehicle |
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|---|---|
| CN103066825B (en) | 2016-03-09 |
| CN102437725A (en) | 2012-05-02 |
| CN103066825A (en) | 2013-04-24 |
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