CN205596008U - Vice limit feedback control circuit - Google Patents
Vice limit feedback control circuit Download PDFInfo
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- CN205596008U CN205596008U CN201620158437.2U CN201620158437U CN205596008U CN 205596008 U CN205596008 U CN 205596008U CN 201620158437 U CN201620158437 U CN 201620158437U CN 205596008 U CN205596008 U CN 205596008U
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Abstract
The utility model discloses an in order to solve the technical problem that current switching power supply meets on feedback control, provides a vice limit feedback control circuit, be applicable to the secondary circuit's of the vice limit winding formation that has the primary circuit that forms by the primary side winding of transformer and transformer isolation converter, include that vice limit modulation, sending module carry out the data signal that the digit sampling obtained the vice limit sampling information of sign to secondary circuit's output voltage, produce the modulated voltage on making output voltage to this data signal in the demagnetization stage again to it sends to act on the vice limit of transformer winding to this modulated voltage, former edge joint is received, demodulation module, through with former limit auxiliary winding detectable to the modulated voltage of vice limit winding voltage proportional, on former limit the data signal who the transmits reduction of decoding.
Description
Technical field
This practicality newly newly relates to switch power controller, particularly to the secondary side feedback control circuit of Magnetic isolation.
Background technology
In order to avoid loading the interference to energization input and destruction, isolation type switch power changer has become various confession
Part indispensable in electricity system.The isolation between output voltage and input voltage should be realized again output voltage stabilization
In setting value, it is necessarily required to use isolating device that the size of output voltage is fed back to input side and is adjusted controlling.Fig. 1 is
Conventional secondary side feedback controls technology, and the isolation that the task of isolation feedback is made up of device TL431, optocoupler and additional device is amplified
Device undertakes.Ultimate principle is: the trsanscondutance amplifier of the element compositions such as TL431 and sampling resistor R1, R2 is output voltage and base
The error voltage signal of quasi-voltage is enlarged into current signal, and the electric current flowing through TL431 when output voltage is higher becomes big, namely
The electric current flowing through optocoupler becomes big, and the voltage of controller FB port diminishes, thus controller output duty cycle diminishes so that transformator
Transmitting less energy to secondary outfan, output voltage starts to reduce；Otherwise, if output voltage is on the low side, by error is believed
Number feed back to the increase of primary-side-control dutycycle to increase the transmission energy of transformator, thus improve output voltage.The most repeatedly
Constantly regulation controls output voltage stabilization in setting value.This feedback technique is because its detection and comparing element are at changer
Secondary, i.e. loads side, so being called secondary side feedback.The mode of this direct detection output voltage has the spy that precision is high
Point, but owing to these detections, amplifier, the existence of isolation feedback device add the space of power-supply system plate, it is clear that becoming
Advantage is not had on this and volume.Particularly optocoupler can not at high temperature work, and is prone to aging so that the high temperature longevity of this power supply
Order short, it is impossible to meet the application of some high temperature.
Primary side feedback (PSR) technology is developed rapidly in recent ten years, because of its there is no above-mentioned secondary side feedback device and
There is cheap feature, applied in large quantities in the field such as LED illumination and charger for mobile phone.Its schematic diagram is as in figure 2 it is shown, close
The work wave of key node is as it is shown on figure 3, GATESignal is drive waveforms (" main limit " the i.e. transformator of main limit power MOSFET tube
" former limit ", two word synonyms), iPIt is transformer primary winding NPCurrent waveform, iSIt is transformer secondary winding NSCurrent wave
Shape, VAIt is that transformator assists winding NAVoltage waveform.Operation principle is: in voltage and the transformation of degaussing phase auxiliary winding NA
Vice-side winding NS is proportional for device, and the voltage of NS becomes the relation determined with output voltage, thus just may be used by the voltage of sampling VA
The size of output voltage detected, carry out duty ratio modulation according to the voltage detected, if output voltage is higher, reduce duty
Ratio, if output voltage is on the low side, increases dutycycle, makes output voltage stabilization in setting value.Therefore plant feedback system detection and compare
Link is on the former limit of changer, i.e. input voltage side, so being called primary side feedback.It is really by main power transformer
Realize the output voltage feedback to former limit, there is no above-mentioned secondary side feedback such detection feedback element, cost and volume advantage
Prominent.But, it can not complete to replace traditional secondary side feedback technology, because it has self intrinsic shortcoming output electricity
Pressure precision is low.As it is shown on figure 3, the voltage of winding NA is when demagnetization just startsIts
Middle nA is the number of turn of winding NA, and nS is the number of turn of winding NS, and VOUT is output voltage, and VBE is the knot pressure drop of diode, and Vr is secondary
Demagnetization peak point current iSP in limit is in the upper pressure drop produced of dead resistance (including diode internal resistance, trace resistances, electric capacity ESR resistor).
Visible, owing to Vr is to change and big by the Parameters variation of device, before demagnetization terminates, VA can not accurately feed back output
The size of voltage.It is of course also possible to use conventional flex point sample mode, the voltage VA0 of the NA that i.e. samples at the end of demagnetization is fast,
Now secondary erasing current is little to being negligible, and Vr does not takes into account.So,
So far, feedback accuracy improve or can limiting by three aspects: 1., VBE affected, it varies with temperature greatly；2., nA with
The ratio of nS, the precision that can control aborning is also limited；3., sampling precision, not every sample circuit all samples
Voltage at the end of demagnetization just, but in its vicinity.So primary side feedback controls technology in high the answering of output voltage required precision
It is restricted in.Further, the application during the battery of mobile phone got up in latest development fills soon is also restrained, because filling needs soon
Select output voltage according to charge condition at secondary, and the output voltage of primary side feedback be to be determined by the parameter on former limit, it is impossible to
It is changed by control at secondary.
Practical new content
The newest purpose of this practicality is to solve the technical problem that existing Switching Power Supply is run in feedback control, carrying
A kind of method going out brand-new secondary side feedback, it is applicable to have the primary circuit formed by the primary side winding of transformator and transformation
The isolated converter of the secondary circuit that the vice-side winding of device is formed,
Use voltage communication mode, comprise the steps,
Secondary modulation, forwarding step, carry out digital sample to the output voltage of secondary circuit, then this digital signal disappeared
The magnetic stage modulates on output voltage generation modulated voltage, and this modulated voltage is acted on transformer secondary winding carries out sending out
Send；
Former limit receives, demodulation step, can detect that modulated by the former limit auxiliary winding proportional to vice-side winding voltage
Voltage, on former limit the digital signal decoding reduction transmitted.
The carry system code that described digital signal is formed after referring to quantify output voltage, the size of its projection output voltage；
Described modulated voltage refers to that transformator degaussing phase acts on the voltage on vice-side winding, the Changing Pattern of this voltage
Carry the information of described digital signal.
Described modulation refers to the Changing Pattern one_to_one corresponding digital signal Yu modulated voltage, as in digital communication theory
The digital information that the Changing Pattern of carrier wave comprises transmission is the same.
Further, this practicality is new proposes a kind of secondary side feedback Switching Power Supply conversion according to described secondary side feedback method
Device, this Switching Power Supply is according to the size of output voltage, and one size of superposition is prone on former limit the most on the output voltage
The control voltage of auxiliary winding detection, and the voltage after superposition is acted on Switching Power Supply vice-side winding at degaussing phase.Meanwhile,
At the degaussing phase detection former limit auxiliary winding voltage proportional to vice-side winding, just can perception and judge whether superposition this
Control voltage because whether superposition this control voltage be according to the size of output voltage depending on, such that it is able in Switching Power Supply
The size of output voltage is judged on former limit, just output voltage stabilization can set further according to the output of judged result modulation duty cycle
Value.
For realizing above-mentioned functions, the new Switching Power Supply proposed of this practicality includes: three-winding transformer, it is by main limit winding
NP, vice-side winding NS, auxiliary winding NA these three winding composition, they comprise the first port and the second port respectively；Secondary disappears
Magnetic circuit, it comprises the first port and two ports of the second port；Output capacitance, it comprises the first port and the second port two
Port；Feedback switch, it comprises drain electrode port, source electrode port and three ports of gate port；Output voltage coding control module,
It comprises the first port, the second port, three ports of the 3rd port；Detection judge module, it comprises the first port, the second end
Mouth, the 3rd port, the 4th port, five ports of fifth port；The upper resistance of auxiliary winding voltage detection, it comprise the first port and
Second port；The lower resistance of auxiliary winding voltage detection, it comprises the first port and the second port；Feedback switch state-detection mould
Block, it comprises the first port and two ports of the second port；Output voltage decoding feedback module, it comprises the first port and second
Two ports of port；Duty ratio modulation circuit, it comprises the first port, the second port, three ports of the 3rd port.
The annexation of the new Switching Power Supply of this practicality is: first port of described main limit winding NP and input power positive pole
Being connected, the second port is connected with the 3rd port of described duty ratio modulation circuit；First port of described vice-side winding NS, output
First port of electric capacity, the fifth port of detection judge module are connected together, and junction point is just forming switch power source output voltage
Extreme mouth；Second port of described vice-side winding NS, the first port of secondary degaussing circuit, the drain electrode port of feedback switch, inspection
The first port surveying judge module is connected together；Second port of described secondary degaussing circuit, the source electrode port of feedback switch, inspection
Survey the 4th port of judge module, the second port of output capacitance is connected together, and junction point forms switch power source output voltage
Negative pole port；Second port of described output voltage coding control module is connected with the second port of detection judge module；Described
3rd port of output voltage coding control module is connected with the 3rd port of detection judge module；Described auxiliary winding voltage is examined
In survey, the first port of resistance is connected with first port of described auxiliary winding NA；The upper resistance of described auxiliary winding voltage detection
Lower first port of resistance of second port, auxiliary winding voltage detection, feedback switch state detection module the first port together
It is connected；Second port of described feedback switch state detection module and the first port one of described output voltage decoding feedback module
Rise and be connected；Second port of described output voltage decoding feedback module is connected together with the first port of duty ratio modulation circuit；
Second port of the lower resistance of the second port of duty ratio modulation circuit, auxiliary winding voltage detection, second end of auxiliary winding NA
Mouth is connected together, and junction point forms the negative pole end of input power.
The operation principle of the new Switching Power Supply of this practicality is as follows:
Described detection judge module each cycle completes two tasks.First task is detection output voltage and internal base
Quasi-voltage compares and draws judged result, and result is passed to described output voltage coding-control by its second port
Module；Second task is to judge degaussing phase by detecting the vacuum magnitude between its first port and the 4th port, and
This information is passed to described output voltage coding control module by its 3rd port.
Described output voltage coding control module completes two tasks in each cycle.First task is, according to reception
To about output voltage size judged result according to agreement communication protocol encode；Second task is, according to institute
State the conducting state encoding the designated time control feedback switch at degaussing phase.
The communication protocol of described agreement refers to, compiles the switch power source output voltage sampled according to predetermined rule
Number, during the decoding on former limit, give tacit consent to again this coding rule, it is therefore an objective to may determine that output voltage is the most higher or on the low side.
Concrete coding and decoding process can be understood by the explanation in detail of embodiment.
The designated time of described degaussing phase refers to, secondary side feedback switch is about scheduled on certain moment of degaussing phase or the period is moved
Make, in this predetermined time period, the detection module on former limit senses that this action just thinks effective.
Described conducting state is to show the suitable driving voltage of feedback switch to make it be operated in high resistance area or low-resistance region, high resistant
Be relative with low-resistance rather than set absolute boundary, they differ only in that feedback switch is produced controls voltage energy
No survey and correctly judge the change of its resistance state at former frontier inspection.
Described secondary degaussing circuit is in the conduction state at transformer secondary winding degaussing phase, and the energy storage for transformator is given
Output capacitance charging provides path；It is in high-impedance state at non-degaussing phase, prevents the electric charge of output capacitance from pouring in down a chimney.
The function that described feedback switch state detection module realizes is, passes through auxiliary in the designated time of described degaussing phase
Winding voltage detect upper and lower resistance dividing potential drop sample auxiliary winding voltage, and the voltage of current detection with adopt before
Sample to voltage compare, whether exceeded setting value according to the amplitude of variation of voltage and judged the conducting state of feedback switch
Whether change, judge the change direction of feedback switch conducting state according to the change direction of voltage.That is, the electricity detected
The amplitude that pressure increases exceedes setting value, then it is assumed that feedback switch has jumped to high-impedance state from low resistance state；Otherwise, the voltage detected
The amplitude reduced exceedes setting value, then it is assumed that feedback switch has jumped to low resistance state from high-impedance state.Then, this module is resistance state
Change information passes to described output voltage decoding feedback module by its second port.
Described output voltage decoding feedback module is carried out further according to the communication protocol arranged after receiving resistance state change information
Decoding, it is judged that output voltage is higher or on the low side.If the result of this cycle decoder is that " switch power source output voltage is higher
", then it is gradually reduced this modulation voltage, until " switch power source output voltage is on the low side " occurs；Otherwise, if currently decoding
Result be " switch power source output voltage is on the low side ", then be gradually increased this modulation voltage, until occur " Switching Power Supply output electricity
Press higher " till.
Described duty ratio modulation circuit receives the modulation voltage of output voltage decoding feedback module output, and according to this voltage
The dutycycle of size modulations transformer primary winding NP excitation, modulation voltage increase then increases dutycycle, otherwise then reduces and account for
Empty ratio.
In sum, the feedback control simplification process of the Switching Power Supply that this practicality is the newest is: secondary sampler output voltage →
Coding → control feedback switch resistance state change → former frontier inspection survey resistance state change → decoding → produce voltage modulated dutycycle.It is visible,
It both need not optocoupler also without other extra isolation transmitter part, thus not only avoids these devices itself to be carried
Some inherent shortcomings come, there will not be the device added for assisting the work of these devices, reduce volume and cost, the most also
Do not have the problem that the output voltage precision of primary side feedback technology is low and can not be changed output voltage at secondary by control.
Making volume, cost, performance arrive optimization, the scope of application is wider.
Accompanying drawing explanation
Fig. 1 is the typical application circuit figure of tradition secondary side feedback switch converters；
Fig. 2 is the typical application circuit figure of tradition primary side feedback switch converters；
Fig. 3 is the key node working waveform figure of tradition primary side feedback switch converters；
Fig. 4 is the theory diagram of the secondary side feedback switch converters of the new first embodiment of this practicality；
Fig. 5 is the key signal oscillogram of the secondary side feedback switch converters of the new first embodiment of this practicality；
Fig. 6 is the theory diagram of the secondary side feedback switch converters of the newest second embodiment of this practicality；
Fig. 7 is the theory diagram of the secondary side feedback switch converters of the newest 3rd embodiment of this practicality；
Fig. 8 is the newest 3rd embodiment secondary side feedback switch converters key node work wave of this practicality；
Fig. 9 is the theory diagram of the secondary side feedback switch converters of the newest 4th embodiment of this practicality.
Detailed description of the invention
In order to be more fully understood that the new cenotype of this practicality for the improvement done by prior art, to this practicality the newest three
Before kind detailed description of the invention is described in detail, the prior art being first previously mentioned background section combines accompanying drawing and is said
Bright, and then draw the inventive concept of this case.
As it is shown in figure 1, be existing traditional secondary side feedback switch converters, for transformer isolation changer, including transformation
Primary side winding NP of device, vice-side winding NS and auxiliary winding NA, formed the former of switch converters by primary side winding NP of transformator
Limit circuit, the vice-side winding NS of transformator forms the secondary circuit of switch converters, and the task of this secondary side feedback is by optocoupler and auxiliary
The isolated amplifier helping device to form undertakes.The mode of this direct detection output voltage has the advantages that precision is high, but
Owing to these detections, amplifier, the existence of isolation feedback device add the space of power-supply system plate, it is clear that at cost and volume
On there is no advantage.Particularly optocoupler can not at high temperature work, and is prone to aging so that the high temperature service life of this power supply is short, nothing
Method meets the application of some high temperature.
The detailed description of the invention that this practicality is the newest, it is simply that for light-coupled isolation of the prior art feedback existing for many
Improvement done by problem.What this practicality was the newest substantially improves thinking is to remove optocoupler, by former and deputy polygonal voltage communication technology,
Carry out isolated feedback transmission.
The newest initial scheme of this practicality is, a kind of secondary side feedback control method, it is adaptable to have by the former limit of transformator
The isolated converter of the secondary circuit that the primary circuit of winding formation and the vice-side winding of transformator are formed,
Use voltage communication mode, comprise the steps,
Secondary modulation, forwarding step, carry out digital sample and obtain characterizing secondary voltage letter the output voltage of secondary circuit
The digital signal of breath, then this digital signal is modulated generation modulated voltage on output voltage at degaussing phase, and this is modulated
Voltage acts on transformer secondary winding and is transmitted；
Former limit receives, demodulation step, can detect that modulated by the former limit auxiliary winding proportional to vice-side winding voltage
Voltage, on former limit the digital signal decoding reduction transmitted.
Thus conceiving, the modulation of refinement secondary, sending method, comprise the steps further,
Secondary sampler step, carries out digital sample to the output voltage of secondary circuit, obtain represent secondary output voltage with
Two digital signals of the multilevel iudge result of internal reference voltage, and by digital data transmission to coding control module；
Re-encoding control step, receives digital signal, and according to pre-arranged code rule, two digital signal correspondences is compiled as
High and low two kinds of level signals, output is to compression module；
Pressurization steps, accepts level signal, and works in two states according to two kinds of level signals control prelum correspondences, with
Secondary sampler signal is added on output voltage with voltage signal form.
In described pressurization steps, two kinds of level signals control two kinds of resistance states of prelum correspondence work, are
When prelum works in the first resistance state, produce the first voltage signal, with by the first numeral of secondary sampler signal
Signal, with the first voltage signal form of prelum, is added on output voltage, produces modulated voltage, and this modulated voltage effect
It is transmitted in transformer secondary winding；
When prelum works in the second resistance state, produce the second voltage signal, with by the second numeral of secondary sampler signal
Signal, with the second voltage signal form, is added on output voltage, produces modulated voltage, and this modulated voltage is acted on transformator
Vice-side winding is transmitted；Make the second judging result signal of output voltage with output voltage synchronous transfer.
Conceived by aforementioned techniques, refine the reception of former limit, demodulation method further, comprise the steps,
Former limit detecting step, within the scheduled time of degaussing phase, samples to the terminal voltage of former limit auxiliary winding,
To the induced voltage of relation proportional to modulated voltage as former limit sampled signal, and from induced voltage, extract secondary adjust
The secondary sampler information make, sent is as comparative result signal, and exports comparative result to decoding control block；
Decoding rate-determining steps, receives the comparative result signal of former limit sampling, according to pre-arranged code rule, by comparative result signal
Being reduced to level signal, output is to duty ratio modulation circuit.
Optimize the reception of former limit further, demodulation method scheme is, in the detecting step of described former limit, extracts from induced voltage
The secondary sampler information go out secondary modulation, sending, is by current former limit sampled voltage signal and former limit sampled voltage letter before
Number compare, whether exceed setting value according to the amplitude of variation of voltage and judge whether the conducting state of prelum changes
Become, and judge the change direction of prelum conducting state according to the change direction of voltage.
Each step in above method, the modularized circuit that all can be exchanged into corresponding function realizes.
I.e. a kind of secondary side feedback control circuit, it is adaptable to there is the primary circuit and change formed by the primary side winding of transformator
The isolated converter of the secondary circuit that the vice-side winding of depressor is formed, including,
Secondary modulation, sending module, carry out digital sample and obtain characterizing secondary voltage letter the output voltage of secondary circuit
The digital signal of breath, then this digital signal is modulated generation modulated voltage on output voltage at degaussing phase, and this is modulated
Voltage acts on transformer secondary winding and is transmitted；
Former limit receives, demodulation module, can detect that modulated by the former limit auxiliary winding proportional to vice-side winding voltage
Voltage, on former limit the digital signal decoding reduction transmitted.
Wherein, secondary modulation, sending module, including,
Secondary detection judge module, carries out digital sample to the output voltage of secondary circuit, obtains representing secondary output electricity
Two digital signals of the multilevel iudge result of pressure and internal reference voltage, and by digital data transmission to coding control module；
Coding control module, receives digital signal, and according to pre-arranged code rule, two digital signal correspondences is compiled as
High and low two kinds of level signals, output is to compression module；
Compression module, accepts level signal, and works in two states according to two kinds of level signals control prelum correspondences, with
Secondary sampler signal is added on output voltage with voltage signal form.
Design compression module further, be to control prelum correspondence by two kinds of level signals to be operated in two kinds of resistance states, i.e.
When prelum works in the first resistance state, produce the first voltage signal, with by the first numeral of secondary sampler signal
Signal, with the first voltage signal form of prelum, is added on output voltage, produces modulated voltage, and this modulated voltage effect
It is transmitted in transformer secondary winding；
When prelum works in the second resistance state, produce the second voltage signal, with by the second numeral of secondary sampler signal
Signal, with the second voltage signal form, is added on output voltage, produces modulated voltage, and this modulated voltage is acted on transformator
Vice-side winding is transmitted；Make the second judging result signal of output voltage with output voltage synchronous transfer.
The former limit of another design receives, demodulation module, including,
Former limit detection module, within the scheduled time of degaussing phase, samples to the terminal voltage of former limit auxiliary winding,
To the induced voltage of relation proportional to modulated voltage as former limit sampled signal, and from induced voltage, extract secondary adjust
The secondary sampler information make, sent is as comparative result signal, and exports comparative result to decoding control block；
Decoding control block, receives the comparative result signal of former limit sampling, according to pre-arranged code rule, by comparative result signal
Being reduced to level signal, output is to duty ratio modulation circuit.
Design former limit detection module further, the secondary sampler information extract secondary modulation from induced voltage, sending,
It is that current former limit sampled voltage signal is compared with former limit sampled voltage signal before, according to the amplitude of variation of voltage is
No exceed whether setting value changes to the conducting state judging prelum, and judge pressurization according to the change direction of voltage
The change direction of device conducting state.
In order to make this practicality new clearer, below in conjunction with drawings and Examples, new further to this practicality
Describe in detail.Should be appreciated that specific embodiment described herein, only in order to explain that this practicality is new, is not used to limit this
Practical new.Especially, for the operation principle allowing people be easier to understand in this practicality newly, cataloged procedure in an embodiment
Middle logical relation employs specific form and represents, such as " output voltage is higher " this information is with " feedback switch is in height
Resistance state " represent, in actual product realizes, " output voltage is higher " this information also can be with " feedback switch is in low-resistance
State " carry, merely to preferably illustrate that this practicality is new rather than new for limiting this practicality.
Embodiment one
According to the isolation feedback method design that this practicality is the newest, the present embodiment provides a kind of transformer secondary Voltage Feedback
To the device on former limit, as shown in Figure 4, for a kind of secondary side feedback switch converters, it comprises the new secondary side feedback of this practicality and controls
Four control devices of circuit: sampler, manipulator, receptor and demodulator.
Sampler carries out digital sample to output voltage, and analog output voltage is converted into digital signal to be passed；
Manipulator is producing modulated voltage on the digital signal modulated received to output voltage, i.e. at numeral letter to be passed
Make vice-side winding be in the first duty when number being in " 0 " state, and make secondary when digital signal to be passed is in one state
Winding is in the second duty, and the duty that both is different causes the voltage difference at vice-side winding two ends, this change
The voltage changed is delivered to primary side winding by the coupling of transformator from vice-side winding；
Receptor, by the detection to primary side winding voltage, perceives two kinds of different operating states that transformator transmits；
Demodulator goes out to solve digital signal according to the different operating state decoded back of receptor perception.
For clearly illustrating work process, as it is shown in figure 5, list the new secondary side feedback switch converters of this practicality
At the signal waveform of key node, each signal name and the one_to_one corresponding in Fig. 4.
Bsend is digital signal to be passed, and it is to output voltage V by samplerOUTCarry out sampling to obtain；Vsend be through
Modulated voltage after the modulation of ovennodulation device, i.e. in the voltage difference at degaussing phase vice-side winding two ends, it is by numeral waiting for transmission
Signal is modulated on the output voltage and is formed, i.e. modulated voltage Vsend=output voltage+Δ Vsend, and wherein, Δ Vsend is numeral
The modulation voltage of signal, is i.e. the voltage added by compression module, so that modulated voltage contains the full detail of digital signal；
VA is the voltage signal that receptor receives on the auxiliary winding of former limit；Vrecv is the former frontier inspection that VA sampling is obtained by receptor
Survey signal, its size relation proportional to modulated voltage Vsend；Brecv is the decoded back digital signal of solution out, it
To be demodulator survey signal decoding according to former frontier inspection obtains, and the digital information expressed by Brecv Yu Bsend is the same, be by
In transmission delay interval the most in time.
As it is shown in figure 5, t1～t2, t3～t4, t5～t6 are degaussing phase, digital signal was transmitted in this stage.
In t1～the t2 time period, digital signal to be passed is " 0 ", and vice-side winding is in the first duty, i.e. above it
Voltage Vsend not superposition Δ Vsend, the voltage that receptor receives also is not superposition Δ Vrecv；
In t3～the t4 time period, digital signal to be passed is " 1 ", and vice-side winding is in the second duty, i.e. above it
Voltage Vsend be superposition Δ Vsend, the voltage that receptor receives also is superposition Δ Vrecv；
In t5～the t6 time period, digital signal to be passed is " 0 ", and vice-side winding is in the first duty, i.e. above it
Voltage Vsend be not superposition Δ Vsend, the voltage that receptor receives also is not superposition Δ Vrecv；
Decoder is demodulated according to the Vrecv signal received: do not find change thus Brecv at t2 moment Vrecv
Keep original " 0 " digit order number；At t4 moment Vrecv voltage from low height and the amplitude of changing to beyond setting value, it is believed that state occurs
Change, thus change to " 1 " digit order number from " 0 " digit order number；Change from high to low and amplitude is beyond setting at t6 moment Vrecv voltage
Definite value, it is believed that state there occurs change, thus changes to " 0 " digit order number from " 1 " digit order number.
Visible, digital signal to be passed " 010 ", the digital signal of solution obtained on former limit by transmission is also " 010 ".
Embodiment two
As shown in Figure 6, being the circuit diagram of the present embodiment Switching Power Supply, a kind of secondary side feedback switch converters, it includes: three
Winding transformer, it by main limit winding NP, vice-side winding NS, auxiliary winding NA these three winding form, wherein winding NP comprises
First port 102 and the second port 103, winding NS comprises the first port 104 and the second port 105, and winding NA comprises the first end
Mouth 106 and the second port 107.Secondary manipulator is made up of compression module and coding control module, wherein, and compression module, including
Secondary degaussing circuit and feedback switch, feedback switch is i.e. prelum, secondary degaussing circuit, and it comprises the first port 110 and
111 two ports of Two-port netwerk；Output capacitance, it comprises the first port 131 and 132 two ports of the second port；Feedback switch, it
Comprise drain electrode port, source electrode port and three ports of gate port.Output voltage coding control module, it comprises the first port
112, second port the 113, the 3rd 114 3 ports of port；Secondary sampler device, uses detection judge module, and it comprises the first end
Mouth the 115, second port the 116, the 3rd port the 117, the 4th port 118,119 5 ports of fifth port；Auxiliary winding voltage is examined
Resistance in survey, it comprises the first port 120 and the second port 121；The lower resistance of auxiliary winding voltage detection, it comprises the first port
122 and second port 123；Feedback switch state detection module, it comprises the first port 124 and 125 two ports of the second port；
Output voltage decoding feedback module, it comprises the first port 126 and 127 two ports of the second port；Duty ratio modulation circuit, it
Comprise first port the 128, second port the 129, the 3rd 130 3 ports of port.
Their annexation is: port 102 is connected with the positive terminal 101 of input power, port 103 and port 130 phase
Even；Port 104, port 131, port 119 are connected together, and junction point forms the positive pole port 108 of switch power source output voltage；End
Mouth 105, port 110, the drain electrode port of feedback switch, port 115 are connected together；Port 111, port 118, the source of feedback switch
Extreme mouth, port 132 are connected together, and junction point forms the negative pole port 109 of switch power source output voltage；Port 113 and port
116 are connected；Port 114 is connected with port 117；Port 120 is connected with port 106；Port 121, port 122, port 124 are together
It is connected；Port 125 is connected together with port 126；Port 127 is connected together with port 128；Port 129, port 123, port
107 are connected together, and junction point forms the negative pole end of input power.
The excitation process of this flyback sourse changer is the same with tradition anti exciting converter, it differs in that such as
Where degaussing phase feeds back to former limit from secondary the change information of output voltage.Concrete operation principle is:
Detection two detection effects of judge module.First, it detects the output voltage of Switching Power Supply by port 119, and
This voltage is compared with internal reference voltage, and result of the comparison can determine to feed back MOS switch at transformator degaussing phase
The most open-minded.Second, it detects what the conduction voltage drop of demagnetization path realized by 110 ports and 111 ports, on demagnetization rank
Pressure drop ratio port 111 less of section port 110.
Two effects of output voltage coding control module: Coding Effects, agreement coding rule output voltage is from partially
When high state changes to Lower state, feedback switch need to change to low resistive state from high-impedance state, otherwise, output voltage is from the low side
When state changes to higher state, feedback switch need to change to high-impedance state from low resistive state.So, when output voltage is higher anti-
Feedback switch should be at high-impedance state, and feedback switch drive level is encoded as low level；When output voltage is on the low side, feedback switch should be located
In low resistance state, feedback switch drive level is encoded as high level.Control action, controls at feedback switch grid at degaussing phase
In corresponding code level, port 112 output low level when i.e. output voltage is higher, when output voltage is on the low side, port 112 exports
High level.
The transmitting procedure of transformator: because there being output capacitance COUTThe existence of energy storage effect, changer is the most several at one
In cycle, output voltage is that bigger sudden change will not occur, so can ignore electric capacity C at short noticeOUTVoltage VOUTChange
Change.According to the new content of this practicality, it is now desired at VOUTUpper superposition one controls voltage, and for this, we use rectification two
Level pipe is as secondary demagnetization path, and as shown in Figure 6, this is the most also to be the most frequently used mode.Because the knot pressure drop of diode
VBEExistence, feedback MOS switch when degaussing phase is not opened, winding NSPort 104 with the pressure reduction minima of port 105 is
(VOUT+VBE)；Feedback MOS switch when degaussing phase is opened, winding NSPort 104 is (V with the pressure difference of port 105OUT+
Vsdon), wherein VsdonBe feedback MOS switch conducting time source electrode and drain electrode between pressure reduction because feedback MOS switch pipe internal resistance
Little, VsdonLess than VBE.Visible, degaussing phase feeds back the conducting of MOS switch and is not turned on there occurs so that the pressure reduction at winding two ends
Bigger sudden change, by conversion, at the port 124 of feedback switch state detection module, change in voltage size is: WhereinIt it is the ratio of winding NA and the winding NS number of turn.
The detection judge process of feedback switch state detection module: in order to allow people understand this transmitting procedure more intuitively,
One supply convertor of design illustrates specifically below.Select VBE=0.4V, feeds back MOS switch pipe conduction voltage drop Vsdon=
0.06V, So feedback MOS switch pipe turns on and is not turned on, and detects at port 124
Voltage change is Δ V124=(0.4V-0.06V) × 3 × 0.2=0.2V.The voltage of each cycle detection port 124, if this
The voltage in the voltage ratio previous cycle that the cycle obtains exceeds setting value Δ Vref=0.1V, then may determine that feedback switch from
Low resistance state LRChange to high-impedance state HR；Otherwise, then may determine that feedback switch is from high-impedance state HRChange to low resistance state LR。
In order to make this correct judgment errorless, requiring to ensure by following two, first is exactly Δ Vref < Δ V124, namely
Detection module can interpolate that out this voltage jump；Second be the voltage compared be separated by periodicity can not be excessive, because only that
Time is short just can ignore VOUTThe change of voltage, it is to avoid because of VOUTLarge change and produce erroneous judgement.
Decoding and duty ratio modulation process: according to the coding rule of agreement in cataloged procedure, it should about definite decoding rule is,
Correspondingly decode when receiving the judged result of " feedback switch changes to low resistive state from high-impedance state " " output voltage from
Higher state changes to Lower state ", otherwise, when the judgement receiving " feedback switch changes to high-impedance state from low resistive state "
" output voltage changes to higher state from Lower state " is correspondingly decoded during result.If decoded result be " output voltage from
Higher state changes to Lower state ", before showing to change, output voltage is higher, and current output voltage is on the low side, directly
To again receiving the most reverse state change；Otherwise, it is appreciated that current output voltage is higher.Visible, as long as pressing
The communication protocol constituted according to the two agreement is controlled and transmits, just can be the size of isolating transformer secondary output voltage
Feed back its former limit.Modulation voltage V it is gradually reduced when output voltage is highercrl, it controls dutycycle and is gradually reduced, thus causes
Output voltage is made to reduce；Otherwise, it is gradually increased dutycycle when output voltage is on the low side and makes it again raise.The most repeatedly, output
Voltage stabilization is in setting value.
Embodiment three
As it is shown in fig. 7, be the circuit diagram of the present embodiment three, with being a difference in that of embodiment two, there is no secondary demagnetization electricity
Road and feedback switch, the substitute is rectified feedback switch, be i.e. the rectifier tube in traditional switch changer secondary circuit.Whole
Stream feedback switch comprises three ports, and the first port 233 is connected with the second port 105 of vice-side winding, and the second port 234 is with defeated
Going out voltage code control module the 3rd port 112 to connect, the 3rd port 235 is connected with Switching Power Supply output negative pole end 109.
The working method of the rectified feedback switch in the present embodiment is, time period rectified feedback switch outside degaussing phase
It is off, prevents the electric charge in output capacitance from pouring in down a chimney；It is change in its duty of degaussing phase, is as shown in Figure 8
The voltage waveform of auxiliary winding NA, opens at T1 period rectified feedback and provides demagnetization path into transformator, play rectification
Effect.But the conducting state switched at T2 period rectified feedback is determined by the size of output voltage, plays output voltage feedback
Effect, i.e. use as prelum.If opening, auxiliary winding NA voltage waveform as shown in curve 1 in Fig. 8, if the most open-minded
Electric current can pass through from the body diode of feedback MOS switch pipe, then assist the waveform of winding as shown by curve 2, both difference works
Make state and just defined two kinds of configurations, be used for carrying the information of output voltage size.
According to the summary of the invention that this practicality is the newest, the change of feedback switch resistance state can be transmitted by the designated time
Change.Now agreement feedback switch state detection module detects winding voltage at the end of fast demagnetization, then detect at voltage curve 1
To voltage swing be V1, the waveform detected at voltage curve 2 is V2.Actually voltage V2 is whole with the difference of voltage V1
The body diode pressure drop of stream feedback switch, as long as the control voltage of this sudden change of state detection module just can perceive feedback switch
State, thus learn the size of output voltage.
The coding of output voltage, decoding, this whole process of Duty ratio control are above illustrating, at this not
Repeat again.
Embodiment four
The newest core of the most easy to understand practicality is, the resistance by feedback switch of the size information of output voltage
State change carries, and the produced voltage that controls of the change of feedback switch resistance state is coupled to former limit from isolating transformer vice-side winding
Auxiliary winding, perceive respective change on former limit and judge the size of output voltage, from what control dutycycle make output electricity
Pressure is stable.I.e. feedback switch is as prelum.So, how to produce that to control voltage in this as the mode of information carrier be multiple
Various, the circuit of the present embodiment is the most also good selection, as shown in Figure 9.
The present embodiment is with the difference of embodiment two, the feedback switch in compression module and demagnetization paths connected in series,
The conducting state controlling feedback switch also can produce required control voltage.Because degaussing circuit can cut voluntarily after demagnetization terminates
The electric charge only preventing output capacitance pours in down a chimney, thus the control to feedback switch need not sample degaussing phase and reduces Switching Power Supply
Realize difficulty, this is its outstanding advantages.
Claims (5)
1. a secondary side feedback control circuit, it is adaptable to there is the primary circuit and transformator formed by the primary side winding of transformator
The isolated converter of secondary circuit that formed of vice-side winding, including,
Secondary modulation, sending module, carry out digital sample and obtain characterizing secondary voltage information the output voltage of secondary circuit
Digital signal, then this digital signal is modulated generation modulated voltage on output voltage at degaussing phase, and this modulated voltage
Act on transformer secondary winding to be transmitted；
Former limit receives, demodulation module, can detect that modulated voltage by the former limit auxiliary winding proportional to vice-side winding voltage,
On former limit the digital signal decoding reduction transmitted.
Secondary side feedback control circuit the most according to claim 1, it is characterised in that: the modulation of described secondary, sending module, bag
Include,
Secondary detection judge module, the output voltage of secondary circuit is carried out digital sample, obtain represent secondary output voltage with
Two digital signals of the multilevel iudge result of internal reference voltage, and by digital data transmission to coding control module；
Coding control module, receives digital signal, and according to pre-arranged code rule, is compiled as high and low by two digital signal correspondences
Two kinds of level signals, output is to compression module；
Compression module, accepts level signal, and works in two states, with by pair according to two kinds of level signals control prelum correspondences
Limit sampled signal is added on output voltage with voltage signal form.
Secondary side feedback control circuit the most according to claim 2, it is characterised in that: described compression module, by rectification two pole
Pipe and feedback switch form, and feedback switch is a N-type metal-oxide-semiconductor, and its concrete annexation is, the negative electrode of commutation diode and secondary
The different name end of winding connects, and the anode of commutation diode is connected with output negative terminal；The grid of N-type metal-oxide-semiconductor and coding control module
Connecting, the drain electrode of N-type metal-oxide-semiconductor connects with the negative electrode of commutation diode, and the source electrode of N-type metal-oxide-semiconductor is connected with the anode of commutation diode,
In order at degaussing phase, by the first digital signal of secondary sampler signal, to produce when working in the first resistance state with N-type metal-oxide-semiconductor
First voltage signal form, is added on output voltage；And by the second digital signal of secondary sampler signal, work with N-type metal-oxide-semiconductor
The the second voltage signal form produced when the second resistance state, is added on output voltage.
Secondary side feedback control circuit the most according to claim 2, it is characterised in that: described compression module, by rectifier tube group
Becoming, be a N-type metal-oxide-semiconductor, its concrete annexation is that the grid of N-type metal-oxide-semiconductor is connected with coding control module, N-type metal-oxide-semiconductor
Drain electrode is connected with the different name end of vice-side winding, and the source electrode of N-type metal-oxide-semiconductor is connected, in order at degaussing phase, by secondary with output negative terminal
First digital signal of sampled signal, the first voltage signal form produced when turning on N-type metal-oxide-semiconductor body diode, it is added to defeated
Go out on voltage；And by the second digital signal of secondary sampler signal, second produced when being not turned on N-type metal-oxide-semiconductor body diode
Voltage signal form, is added on output voltage.
Secondary side feedback control circuit the most according to claim 2, it is characterised in that: described compression module, by diode and P
Type metal-oxide-semiconductor forms, and its concrete annexation is, the negative electrode of commutation diode is connected with the different name end of vice-side winding, rectification two pole
The anode of pipe is connected with the drain electrode of p-type metal-oxide-semiconductor, and the source electrode of p-type metal-oxide-semiconductor is connected with output negative terminal, the grid of p-type metal-oxide-semiconductor and volume
Code control module connects,
In order at degaussing phase, by the first digital signal of secondary sampler signal, produce when turning on N-type metal-oxide-semiconductor body diode
The first voltage signal form, be added on output voltage；And by the second digital signal of secondary sampler signal, with N-type metal-oxide-semiconductor body
The the second voltage signal form produced when diode is not turned on, is added on output voltage.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620158437.2U CN205596008U (en) | 2016-03-01 | 2016-03-01 | Vice limit feedback control circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620158437.2U CN205596008U (en) | 2016-03-01 | 2016-03-01 | Vice limit feedback control circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105610306A (en) * | 2016-03-01 | 2016-05-25 | 深圳南云微电子有限公司 | Secondary feedback control method and secondary feedback control circuit |
| CN111220930A (en) * | 2018-11-23 | 2020-06-02 | 上海海拉电子有限公司 | Electric automobile contactor, and detection device and method for on-off state of fuse |
-
2016
- 2016-03-01 CN CN201620158437.2U patent/CN205596008U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105610306A (en) * | 2016-03-01 | 2016-05-25 | 深圳南云微电子有限公司 | Secondary feedback control method and secondary feedback control circuit |
| CN105610306B (en) * | 2016-03-01 | 2018-12-11 | 深圳南云微电子有限公司 | Secondary side feedback control method and its control circuit |
| CN111220930A (en) * | 2018-11-23 | 2020-06-02 | 上海海拉电子有限公司 | Electric automobile contactor, and detection device and method for on-off state of fuse |
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