CN109768711A - A kind of synchronous commutating control circuit and method - Google Patents
A kind of synchronous commutating control circuit and method Download PDFInfo
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- CN109768711A CN109768711A CN201910150381.4A CN201910150381A CN109768711A CN 109768711 A CN109768711 A CN 109768711A CN 201910150381 A CN201910150381 A CN 201910150381A CN 109768711 A CN109768711 A CN 109768711A
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Abstract
A kind of synchronous commutating control circuit of the present invention, including circuit of synchronous rectification, the first driving circuit its output are connect with circuit of synchronous rectification primary side, its output of the second driving circuit is connect with circuit of synchronous rectification pair side, and cpu controller and the first driving circuit input connection.It further include the primary side connection of one end and circuit of synchronous rectification, the synchronous rectifying controller of the input connection of the other end and the second driving circuit, synchronous rectifying controller includes sample circuit, waveform extracting circuit, shaping latch cicuit, Digital Logical Circuits.This programme judges secondary current beginning and end, by detection resonance potential Lr transient state mutation to control the conducting and cut-off of devices.This programme can not be influenced by switching frequency in full switch frequency range application without following primary side to drive in real time, carry out the synchronously control for following output electric current in real time, realize and improve transfer efficiency.
Description
Technical field
The present invention relates to rectification commutation technique field more particularly to a kind of synchronous commutating control circuit and methods.
Background technique
With the raising required power-efficient, synchronous rectification is had been to be concerned by more and more people, especially DC/DC
Low-voltage, high-current occasion, there are the losses of larger conduction voltage drop for secondary side diode rectification in conventional power source system, in the use of secondary side
(i.e. Metal-Oxide-Semiconductor Field-Effect Transistor abbreviation, Chinese are metal to MOSFET
Oxide semiconductor field effect transistor) replace simple diode rectification come reduce loss, improve efficiency, increasingly at
For a kind of trend.
Existing synchronous rectification has the following deficiencies:
(1) one of existing synchronous rectification mode is that secondary side control technology is followed by primary side, i.e., secondary side driving is driven with primary side
Move it is fully synchronized be consistent, theoretically can be with opening with closing i.e. former pair side when switching frequency is greater than or equal to resonance frequency
It is synchronous to realize.But when resonance frequency is higher than switching frequency in LLC resonance circuit, there can be secondary current and be driven compared with primary side
It advances to zero and one section of plateau time situation occurs, be connected, break in advance not in time if secondary side driving is still synchronous with primary side at this time
Open, can exist primary current it is excessive in addition damage switching tube risk.
(2) the two of existing synchronous rectification mode are to be led to using refined up to ORing field-effect tube (being also metal-oxide-semiconductor) control mode
Overcurrent flows through rectifier diode and generates pressure drop signal to draw the mode of logical synchronous rectifier, such as technical information the 2nd phase in 2018
Article number: 1009-2552 (2018) 02-0055-04 " circuit of synchronous rectification of the LLC topology of G2 50A " synchronizes original
It is as shown in Figure 1 to manage circuit.Its working principle and process are as follows: when there is S pole (source electrode) of the main circuit current from devices M1
When flowing through the pole D (drain electrode) by body diode, VF (about 0.7V) pressure drop can be generated, at this moment the D pole tension of M1 is lower than S pole tension,
The then left side triode ON of Q1, the cut-off of the right triode, push-pull circuit export high level, and M1 conducting, electric current is from body diode
Turning to RDS (on) inside M1, [RDS (ON) is when field-effect tube (being also metal-oxide-semiconductor) is connected between drain D and source S between D, S
Resistance]；After main circuit current zero passage is reversed, the D pole tension of M1 is higher than S pole tension, and at this moment the triode on the left side Q1 can end,
The right triode ON, push-pull output low level end M1, this circuit is simple, and component is few, and cost is cheap.
But the circuit is very high to protection triode Q1 and diode D2 internal symmetry module coherence request, especially
Be cause Vd voltage to mislead when temperature change is inconsistent, simultaneously as M1 be connected when SD (source-leakage) interpolar pressure drop it is very small,
Being formed in synchronous rectification drive control circuit is not thoroughly one open-one close to two triodes of pipe, actually whole when synchronizing
The right triode ON when flowing metal-oxide-semiconductor M1 cut-off, the left side is completely switched off, two triodes when devices M1 conducting
Electric current will be conducted through.Electric current is bigger, and devices D pole tension is lower, and the electric current that left side triode flows through is got over
More, the electric current that the right is flowed through is fewer, and the driving signal of control circuit output is higher；Accordingly, there exist driving electricity when electric current rising
Pressure is higher than driving voltage problem when electric current decline.The driving voltage of devices and the electric current of metal-oxide-semiconductor is flowed through at just
Than load is bigger, and driving voltage is higher；Conversely, driving signal is lower.And driving voltage is low, be usually associated with loss it is big,
The problem of low efficiency.
On the other hand, due also to the effect of metal-oxide-semiconductor package parasitic inductance and PCB lead-in inductance, synchronous commutating control circuit
Vsd ' (source-drain electrodes) voltage detected is higher than ideal Vsd (i.e. when electric current increases (from S extremely toward D extremely forward flow)
When not considering parasitic inductance and lead-in inductance) voltage, and it is less than ideal Vsd voltage when electric current reduction.In addition due to leakage inductance etc.
Parasitic inductance influences, and Vsd ' voltage is often associated with ring jitter problem and the risk of false triggering devices conducting occurs.
Therefore, there are the higher problems of component coherence request for the synchronous rectification detection circuit, simultaneously because metal-oxide-semiconductor is parasitic
Inductance and pcb lead-in inductance and while causing high when driving voltage it is low cause metal-oxide-semiconductor conducting degree inconsistent, efficiency is by larger shadow
It rings.
Above-mentioned in order to overcome the shortcomings of, we have invented a kind of synchronous commutating control circuit and methods.
Summary of the invention
Goal of the invention of the invention is to solve in existing synchronous rectification mode when resonance frequency is higher than in LLC resonance circuit
When switching frequency, there are secondary currents to advance to zero compared with primary side driving, if secondary side driving or conducting synchronous with primary side are not at this time
Disconnect in advance in time, can exist primary current it is excessive in addition damage switching tube risk, using it is refined up to ORing field-effect tube control
Requirement of the mode to circuit internal symmetry module and component is very high, causes driving voltage by parasitic inductance and lead-in inductance
When it is high when low cause that metal-oxide-semiconductor conducting degree is inconsistent, the problem of efficiency is a greater impact.Its specific solution is as follows:
A kind of synchronous commutating control circuit, including circuit of synchronous rectification, the first driving circuit its output with it is described synchronous whole
The connection of current circuit primary side, its output of the second driving circuit connect with circuit of synchronous rectification pair side, cpu controller and described the
One drive circuit input connection.It further include that one end is connect with the primary side of the circuit of synchronous rectification, the other end and described second drives
The synchronous rectifying controller of the input connection of dynamic circuit, the synchronous rectifying controller include:
Sample circuit, input terminal are connect with the both ends of the resonant inductance of the circuit of synchronous rectification primary side respectively；
Waveform extracting circuit, input are connected with sample circuit output；
Shaping latch cicuit, input are connect with the waveform extracting circuit output；
Digital Logical Circuits, input are connected with shaping latch cicuit output, output and the second driving electricity
The input on road connects.
Further, the circuit of synchronous rectification includes at least first switch metal-oxide-semiconductor Q1, second switch metal-oxide-semiconductor Q2, resonance
Inductance Lr, the first resonant capacitance Cr1, the second resonant capacitance Cr2, magnetizing inductance Lm, switch positioned at switch transformer Tx primary side
Transformer Tx, the first devices Q3, the second devices Q4, output capacitance Co, output loading RL.
First switch metal-oxide-semiconductor Q1 drain electrode is connect with input voltage source Vin anode and first one end resonant capacitance Cr1 simultaneously,
First switch metal-oxide-semiconductor Q1 source electrode is connect with second switch metal-oxide-semiconductor Q2 drain electrode and the one end resonant inductance Lr simultaneously, and resonant inductance Lr is another
One end is connect with the one end magnetizing inductance Lm and switch transformer Tx primary Same Name of Ends simultaneously, and the magnetizing inductance Lm other end and switch become
The primary different name end depressor Tx is connect with the first resonant capacitance Cr1 other end and second one end resonant capacitance Cr2 simultaneously, the second resonance
The capacitor Cr2 other end and second switch metal-oxide-semiconductor Q2 source electrode and input voltage source Vin cathode are connect with the ground of primary side simultaneously.The
One switch metal-oxide-semiconductor Q1 grid and second switch metal-oxide-semiconductor Q2 grid are connect with the output of first driving circuit respectively.
Tx grade different name end of switch transformer and the first devices Q3 drain electrode connect, Tx grade of switch transformer
Same Name of Ends and the second devices Q4 drain electrode connect, Tx grade centre tap of switch transformer at the same with output capacitance Co
It is connected with one end of output loading RL, the first devices Q3 source electrode, the second devices Q4 source electrode, output electricity
The other end for holding Co and output loading RL is connect with the ground on secondary side simultaneously；First devices Q3 grid, second synchronize it is whole
Stream metal-oxide-semiconductor Q4 grid is connect with the output of second driving circuit respectively.
Further, the sample circuit includes at least the resistance R1 and R2 of input terminal, the other end of resistance R1 simultaneously with
3 feet of operational amplifier U1 are connected with the one end resistance R3, the other end of resistance R2 while 4 feet and resistance with operational amplifier U1
The connection of the one end R4, resistance R4 other end ground connection, the resistance R4 other end are connect with 1 foot of output of operational amplifier U1, operation amplifier
5 feet of device U1 meet power supply VCC+, and 2 feet of operational amplifier U1 meet power supply VCC-.
Further, the waveform extracting circuit includes at least the output that input is the one end capacitor Cf and operational amplifier U1
The connection of 1 foot, the one end capacitor Cf are connect with the one end resistance Rf, and the resistance Rf other end is as output；Capacitor Cf and resistance Rf composition is high
Circuit passband.The high pass circuit can be one or more levels composition.
Further, it is same for 3 feet of comparator U2 and 4 feet of comparator U3 to include at least input for the shaping latch cicuit
When connected with resistance Rf output, 4 feet of comparator U2,2 feet ground connection, 1 foot of comparator U2 is output, 3 feet of comparator U3,2
Foot ground connection, 1 foot of comparator U3 are output；Or 1 foot of comparator U2 and U3 are separately connected the input for latching chip, latch core
The input of the output connection Digital Logical Circuits of piece.
Further, the Digital Logical Circuits includes at least two triggers U4, U5, and inputting is the 3 of trigger U4, U5
Foot is connect with 1 foot of comparator U2, U3 respectively, exports 5 feet for trigger U4, U5.The trigger is that d type flip flop or JK are touched
Hair device or exclusive or are combined with d type flip flop or one kind that is same or combining with d type flip flop.
A kind of synchronous rectification control method, including a kind of above-mentioned synchronous commutating control circuit execute according to the following steps:
Step 1, sample circuit real-time detection resonant inductance Lr both end voltage；
Step 2, waveform extracting circuit extraction resonant inductance Lr transient state is mutated surge waveform；
Step 3, the shaping of shaping latch cicuit is latched as rising edge signal；
Step 4, it is synchronization signal that rising edge signal is latched in Digital Logical Circuits triggering；
Step 5, the second driving circuit drive amplification synchronization signal drives corresponding synchronous rectification.
In conclusion being had the advantages that using technical solution of the present invention
This programme solves in existing synchronous rectification mode when resonance frequency is higher than switching frequency in LLC resonance circuit,
There are secondary currents to advance to zero compared with primary side driving, if secondary side driving or conducting synchronous with primary side are broken in advance not in time at this time
Open, can exist primary current it is excessive in addition damage switching tube risk, using it is refined up to ORing field-effect tube control mode to circuit
The requirement of internal symmetry module and component is very high, low when causing high when driving voltage by parasitic inductance and lead-in inductance makes
At the problem of metal-oxide-semiconductor conducting degree is inconsistent, efficiency is a greater impact.
Since in LLC resonance circuit, secondary current is proportional to the difference of resonance current and exciting current, i.e. output electric current is opened
At the time of beginning and terminate, at the time of being that resonance current is equal with exciting current, and at this time it is also resonant inductance both end voltage hair
At the time of raw overturning.Resonant inductance voltage jump is obvious, and detection is reliable, is not easy to cause the influence of other stray parasitics, and the present invention is logical
Extraction resonant inductance voltage transient jump signal is crossed, the opening and closing signal as corresponding synchronous rectifier；So as to avoid
The sampling distortion for sampling the small signal of weak current, also avoids the influence of the parasitic parameters such as metal-oxide-semiconductor foot stray inductance, and this programme
It without following primary side to drive in real time, can not be influenced by switching frequency in full switch frequency range application, carry out following output in real time
The synchronously control of electric current is realized and improves transfer efficiency.Especially advantage becomes apparent under output short-circuit or light-load mode.
Detailed description of the invention
In order to illustrate the technical solution of the embodiments of the present invention more clearly, below by institute in the description to the embodiment of the present invention
Attached drawing to be used is needed to be briefly described.It should be evident that the accompanying drawings in the following description is only that a part of the invention is real
Example is applied, for those of ordinary skill in the art, without any creative labor, additionally it is possible to attached according to these
Figure obtains other attached drawings.
Fig. 1 is synchronization principles circuit diagram in background technique；
Fig. 2 is a kind of circuit diagram of synchronous commutating control circuit of the present invention；
Fig. 3 is the circuit diagram of synchronous rectifying controller of the invention；
The step of Fig. 4 is a kind of synchronous rectification control method of the invention is schemed；
Fig. 5 is a kind of waveform diagram of synchronous commutating control circuit of the present invention；
Fig. 6 is circuit diagram of the present invention for the synchronous commutating control circuit of full bridge structure；
Fig. 7 is the circuit diagram of JK flip-flop；
Fig. 8 is the circuit diagram that exclusive or is combined with d type flip flop；
Fig. 9 is the circuit diagram of d type flip flop；
Figure 10 is circuit diagram that is same or combining with d type flip flop.
Description of symbols:
Vgs1- switchs metal-oxide-semiconductor Q1 driving signal；
Vgs2- switchs metal-oxide-semiconductor Q2 driving signal；
ILr- resonant inductance Lr electric current；
ILm- magnetizing inductance Lm electric current；
VLr_Samp- resonant inductance Lr sampled voltage；
VLr_Pluse- resonant inductance Lr transient impact voltage；
VLr_CP3- devices Q3 transient impact rising edge；
VLr_CP4- devices Q4 transient impact rising edge；
Vgs3- devices Q3 driving signal；
Vgs4- devices Q4 driving signal；
IQ3- devices Q3 electric current；
IQ4- devices Q4 electric current.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description.Obviously, described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
As shown in Figure 2,3, a kind of synchronous commutating control circuit, including circuit of synchronous rectification, the first driving circuit its output
It is connect with circuit of synchronous rectification primary side, its output of the second driving circuit is connect with circuit of synchronous rectification pair side, cpu controller and
One drive circuit input connection.It further include that the primary side of one end and circuit of synchronous rectification connects, the other end and the second driving circuit
The synchronous rectifying controller of connection is inputted, synchronous rectifying controller includes:
Sample circuit, input terminal are connect with the both ends of the resonant inductance of circuit of synchronous rectification primary side respectively；
Waveform extracting circuit, input are connected with sample circuit output；
Shaping latch cicuit, input are connect with waveform extracting circuit output；
Digital Logical Circuits, input are connected with the output of shaping latch cicuit, the input of output and the second driving circuit
Connection.
Further, circuit of synchronous rectification includes at least first switch metal-oxide-semiconductor Q1, second switch metal-oxide-semiconductor Q2, resonant inductance
Lr, the first resonant capacitance Cr1, the second resonant capacitance Cr2, magnetizing inductance Lm, switch transformation positioned at switch transformer Tx primary side
Device Tx, the first devices Q3, the second devices Q4, output capacitance Co, output loading RL.
First switch metal-oxide-semiconductor Q1 drain electrode is connect with input voltage source Vin anode and first one end resonant capacitance Cr1 simultaneously,
First switch metal-oxide-semiconductor Q1 source electrode is connect with second switch metal-oxide-semiconductor Q2 drain electrode and the one end resonant inductance Lr simultaneously, and resonant inductance Lr is another
One end is connect with the one end magnetizing inductance Lm and switch transformer Tx primary Same Name of Ends simultaneously, and the magnetizing inductance Lm other end and switch become
The primary different name end depressor Tx is connect with the first resonant capacitance Cr1 other end and second one end resonant capacitance Cr2 simultaneously, the second resonance
The capacitor Cr2 other end and second switch metal-oxide-semiconductor Q2 source electrode and input voltage source Vin cathode are connect with the ground of primary side simultaneously.The
One switch metal-oxide-semiconductor Q1 grid and second switch metal-oxide-semiconductor Q2 grid are connect with the output of first driving circuit respectively.
Tx grade different name end of switch transformer and the first devices Q3 drain electrode connect, Tx grade of switch transformer
Same Name of Ends and the second devices Q4 drain electrode connect, Tx grade centre tap of switch transformer at the same with output capacitance Co
It is connected with one end of output loading RL, the first devices Q3 source electrode, the second devices Q4 source electrode, output electricity
The other end for holding Co and output loading RL is connect with the ground on secondary side simultaneously；First devices Q3 grid, second synchronize it is whole
Stream metal-oxide-semiconductor Q4 grid is connect with the output of the second driving circuit respectively.
Further, sample circuit includes at least the resistance R1 and R2 of input terminal, the other end of resistance R1 while and operation
3 feet of amplifier U1 are connected with the one end resistance R3, the other end of resistance R2 while 4 feet and resistance R4 mono- with operational amplifier U1
End connection, resistance R4 other end ground connection, the resistance R4 other end are connect with 1 foot of output of operational amplifier U1, operational amplifier U1
5 feet connect power supply VCC+, 2 feet of operational amplifier U1 connect power supply VCC-.Operational amplifier model can choose TLV271IDBVR
Deng.
Further, waveform extracting circuit includes at least 1 foot of output that input is the one end capacitor Cf and operational amplifier U1
Connection, the one end capacitor Cf are connect with the one end resistance Rf, and the resistance Rf other end is as output；Capacitor Cf and resistance Rf composition is high to be powered
Road.High pass circuit can be one or more levels composition.
Further, shaping latch cicuit include at least input be comparator U2 3 feet and comparator U3 4 feet simultaneously with
Resistance Rf output connection, 4 feet of comparator U2,2 feet ground connection, 1 foot of comparator U2 is output, and 3 feet, 2 feet of comparator U3 connect
Ground, 1 foot of comparator U3 are output.Alternatively, 1 foot of comparator U2 and U3, which is separately connected, latches chip (figure
In be not drawn into) input, latch chip output connection Digital Logical Circuits input.Comparator model can choose
LMV7239M5/NOPB etc..
Further, Digital Logical Circuits includes at least two triggers U4, U5, inputs 3 feet point for trigger U4, U5
It is not connect with 1 foot of comparator U2, U3, exports 5 feet for trigger U4, U5.Trigger is d type flip flop or JK flip-flop or different
Combined with d type flip flop or with or one kind for being combined with d type flip flop.
As shown in figure 4, a kind of synchronous rectification control method, including a kind of above-mentioned synchronous commutating control circuit, according to following
Step executes:
Step 1, sample circuit real-time detection resonant inductance Lr both end voltage；
Step 2, waveform extracting circuit extraction resonant inductance Lr transient state is mutated surge waveform；
Step 3, the shaping of shaping latch cicuit is latched as rising edge signal；
Step 4, it is synchronization signal that rising edge signal is latched in Digital Logical Circuits triggering；
Step 5, the second driving circuit drive amplification synchronization signal drives corresponding synchronous rectification.
A kind of waveform diagram of synchronous commutating control circuit of the present invention is as shown in figure 5, it can be seen from the figure that synchronous rectification
In metal-oxide-semiconductor Q3 waveform VLr_CP3, first transient impact rising edge t0 moment, corresponding devices Q3 driving signal
Vgs3 conducting, second transient impact rising edge t1 moment, the Vgs3 cut-off of corresponding devices Q3 driving signal, the
Three transient impact rising edge t4 moment, the Vgs3 conducting of corresponding devices Q3 driving signal, the 4th transient impact
The rising edge t5 moment, Vgs3 cut-off ... ... so circulation of corresponding devices Q3 driving signal, similarly, synchronous rectification
In metal-oxide-semiconductor Q4 waveform VLr_CP4, first transient impact rising edge t2 moment, corresponding devices Q4 driving signal
Vgs4 conducting, second transient impact rising edge t3 moment, the Vgs4 cut-off of corresponding devices Q4 driving signal, the
Three transient impact rising edge t6 moment, the Vgs4 conducting of corresponding devices Q4 driving signal, the 4th transient impact
Rising edge t7 moment, Vgs4 cut-off ... ... so circulation of corresponding devices Q4 driving signal.
It should be strongly noted that this programme by detection resonance potential Lr transient state mutation, judge secondary current start and
Terminate, to control the conducting and cut-off of devices.Sampling attenuator circuit can also be replaced with transformer, linear optical coupling etc.
In generation, is realized.Resonant inductance transient impact voltage is converted to rising edge signal by shaping latch cicuit, can be kept away by latching chip
Exempt from noise shake and causes false triggering.The circuit includes 2 threshold voltage comparators, and output generates rising edge or failing edge level.
Digital Logical Circuits can be combined realization by NAND gate, it is also possible to which d type flip flop such as SN74AHC74 or T ' trigger or CPLD can
Program logic circuit, which is built, realizes same function and effect.It as is seen in figs 7-10, is optional trigger application circuit.Tool
Body principle belongs to the prior art, repeats no more.
This programme can also be applied to other forms LLC resonance circuit, such as primary side full bridge structure, or secondary side full bridge structure, such as
Shown in Fig. 6.
In conclusion being had the advantages that using technical solution of the present invention
This programme solves in existing synchronous rectification mode when resonance frequency is higher than switching frequency in LLC resonance circuit,
There are secondary currents to advance to zero compared with primary side driving, if secondary side driving or conducting synchronous with primary side are broken in advance not in time at this time
Open, can exist primary current it is excessive in addition damage switching tube risk, using it is refined up to ORing field-effect tube control mode to circuit
The requirement of internal symmetry module and component is very high, low when causing high when driving voltage by parasitic inductance and lead-in inductance makes
At the problem of metal-oxide-semiconductor conducting degree is inconsistent, efficiency is a greater impact.
Since in LLC resonance circuit, secondary current is proportional to the difference of resonance current and exciting current, i.e. output electric current is opened
At the time of beginning and terminate, at the time of being that resonance current is equal with exciting current, and at this time it is also resonant inductance both end voltage hair
At the time of raw overturning.Resonant inductance voltage jump is obvious, and detection is reliable, is not easy to cause the influence of other stray parasitics, and the present invention is logical
Extraction resonant inductance voltage transient jump signal is crossed, the opening and closing signal as corresponding synchronous rectifier；So as to avoid
The sampling distortion for sampling the small signal of weak current, also avoids the influence of the parasitic parameters such as metal-oxide-semiconductor foot stray inductance, and this programme
It without following primary side to drive in real time, can not be influenced by switching frequency in full switch frequency range application, carry out following output in real time
The synchronously control of electric current is realized and improves transfer efficiency.Especially advantage becomes apparent under output short-circuit or light-load mode.
Embodiments described above does not constitute the restriction to the technical solution protection scope.It is any in above-mentioned implementation
Made modifications, equivalent substitutions and improvements etc., should be included in the protection model of the technical solution within the spirit and principle of mode
Within enclosing.
Claims (9)
1. a kind of synchronous commutating control circuit, including its output of circuit of synchronous rectification, the first driving circuit and the synchronous rectification
The connection of circuit primary side, its output of the second driving circuit are connect with circuit of synchronous rectification pair side, cpu controller and described first
Driving circuit input connection；It further include that one end is connect with the primary side of the circuit of synchronous rectification, the other end and second driving
The synchronous rectifying controller of the input connection of circuit, which is characterized in that the synchronous rectifying controller includes:
Sample circuit, input terminal are connect with the both ends of the resonant inductance of the circuit of synchronous rectification primary side respectively；
Waveform extracting circuit, input are connected with sample circuit output；
Shaping latch cicuit, input are connect with the waveform extracting circuit output；
Digital Logical Circuits, input are connected with shaping latch cicuit output, output and second driving circuit
Input connection.
2. a kind of synchronous commutating control circuit according to claim 1, it is characterised in that: the circuit of synchronous rectification at least wraps
First switch metal-oxide-semiconductor Q1, second switch metal-oxide-semiconductor Q2, resonant inductance Lr, the first resonant capacitance Cr1, the second resonant capacitance Cr2 are included,
It is synchronized positioned at the magnetizing inductance Lm of switch transformer Tx primary side, switch transformer Tx, the first devices Q3, second whole
Flow metal-oxide-semiconductor Q4, output capacitance Co, output loading RL；
First switch metal-oxide-semiconductor Q1 drain electrode is connect with input voltage source Vin anode and first one end resonant capacitance Cr1 simultaneously, and first
Switch metal-oxide-semiconductor Q1 source electrode is connect with second switch metal-oxide-semiconductor Q2 drain electrode and the one end resonant inductance Lr simultaneously, the resonant inductance Lr other end
It is connect simultaneously with the one end magnetizing inductance Lm and switch transformer Tx primary Same Name of Ends, the magnetizing inductance Lm other end and switch transformer
The primary different name end Tx is connect with the first resonant capacitance Cr1 other end and second one end resonant capacitance Cr2 simultaneously, the second resonant capacitance
The Cr2 other end and second switch metal-oxide-semiconductor Q2 source electrode and input voltage source Vin cathode are connect with the ground of primary side simultaneously；First opens
It closes metal-oxide-semiconductor Q1 grid and second switch metal-oxide-semiconductor Q2 grid is connect with the output of first driving circuit respectively；
Tx grade different name end of switch transformer and the first devices Q3 drain electrode connect, and Tx grade of switch transformer is of the same name
End is connected with the second devices Q4 drain electrode, Tx grade centre tap of switch transformer and meanwhile with output capacitance Co and defeated
One end connection of RL, the first devices Q3 source electrode, the second devices Q4 source electrode, output capacitance Co are loaded out
It is connect simultaneously with the ground on secondary side with the other end of output loading RL；First devices Q3 grid, the second synchronous rectification
Metal-oxide-semiconductor Q4 grid is connect with the output of second driving circuit respectively.
3. a kind of synchronous commutating control circuit according to claim 1, it is characterised in that: the sample circuit includes at least defeated
Enter the resistance R1 and R2 at end, the other end of resistance R1 is connect with 3 feet of operational amplifier U1 and the one end resistance R3 simultaneously, resistance R2
The other end simultaneously connect with 4 feet of operational amplifier U1 and the one end resistance R4, the resistance R4 other end be grounded, the resistance R4 other end
It is connect with 1 foot of output of operational amplifier U1,5 feet of operational amplifier U1 meet power supply VCC+, and 2 feet of operational amplifier U1 connect confession
Electric VCC-.
4. a kind of synchronous commutating control circuit according to claim 3, it is characterised in that: the waveform extracting circuit at least wraps
Including input is that the one end capacitor Cf is connect with 1 foot of output of operational amplifier U1, and the one end capacitor Cf is connect with the one end resistance Rf, resistance
The Rf other end is as output；Capacitor Cf and resistance Rf forms high pass circuit.
5. a kind of synchronous commutating control circuit according to claim 4, it is characterised in that: the high pass circuit can for level-one or
Multistage composition.
6. a kind of synchronous commutating control circuit according to claim 5, it is characterised in that: the shaping latch cicuit at least wraps
4 feet for including 3 feet and comparator U3 that input is comparator U2 are exported with resistance Rf simultaneously to be connected, and 4 feet, 2 feet of comparator U2 connect
Ground, 1 foot of comparator U2 are output, and 3 feet of comparator U3,2 feet ground connection, 1 foot of comparator U3 is output；Or comparator U2
It is separately connected the input for latching chip with 1 foot of U3, latches the input of the output connection Digital Logical Circuits of chip.
7. a kind of synchronous commutating control circuit according to claim 6, it is characterised in that: the Digital Logical Circuits is at least wrapped
Two triggers U4, U5 are included, inputs and is connect respectively with 1 foot of comparator U2, U3 for 3 feet of trigger U4, U5, are exported as triggering
5 feet of device U4, U5.
8. a kind of synchronous commutating control circuit according to claim 7, it is characterised in that: the trigger be d type flip flop or
JK flip-flop or exclusive or are combined with d type flip flop or one kind that is same or combining with d type flip flop.
9. a kind of synchronous rectification control method, including a kind of synchronous commutating control circuit described in claim 1-8, feature exist
In execution according to the following steps:
Step 1, sample circuit real-time detection resonant inductance Lr both end voltage；
Step 2, waveform extracting circuit extraction resonant inductance Lr transient state is mutated surge waveform；
Step 3, the shaping of shaping latch cicuit is latched as rising edge signal；
Step 4, it is synchronization signal that rising edge signal is latched in Digital Logical Circuits triggering；
Step 5, the second driving circuit drive amplification synchronization signal drives corresponding synchronous rectification.
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| CN113179034A (en) * | 2021-04-26 | 2021-07-27 | 长城电源技术有限公司 | Synchronous rectification control circuit |
| CN114337310A (en) * | 2022-03-10 | 2022-04-12 | 浙江日风电气股份有限公司 | Control method, device and medium for reducing voltage stress |
| WO2022094928A1 (en) * | 2020-11-06 | 2022-05-12 | Telefonaktiebolaget Lm Ericsson (Publ) | Circuit and method for controlling rectifier, and circuit including the rectifier |
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