CN209389697U - A kind of pair side control circuit and its isolated power converting circuit - Google Patents
A kind of pair side control circuit and its isolated power converting circuit Download PDFInfo
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- CN209389697U CN209389697U CN201822002658.2U CN201822002658U CN209389697U CN 209389697 U CN209389697 U CN 209389697U CN 201822002658 U CN201822002658 U CN 201822002658U CN 209389697 U CN209389697 U CN 209389697U
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Abstract
The utility model provides a kind of secondary side control circuit for isolated power converting circuit and corresponding isolated power converting circuit.Wherein secondary side control circuit includes overvoltage protective module; overvoltage protective module is used to provide protection to isolated power converting circuit in output voltage over-voltage; overvoltage protective module includes: the first comparison circuit, for comparing the detection signal and first threshold signal of characterization output voltage；State detection circuit determines the transition state of isolated power converting circuit based on the signal of secondary circuit；And pulse-generating circuit, the comparison result based on the first comparison circuit determines whether to occur over-voltage fault, and selectively secondary side rectifying tube is connected in output over-voltage protection signal to the transition state based on isolated power converting circuit.Over-voltage detection is put into secondary circuit and carried out by pair side control circuit and control method provided by the utility model, improves the detection accuracy and reliability of the output voltage overvoltage protection of isolated power converting circuit.
Description
Technical field
The utility model relates to electronic fields, and in particular to a kind of secondary side control electricity for isolated power converting circuit
Road and its isolated power converting circuit.
Background technique
Overvoltage protection (OVP) is one of most important function in switching power circuit, for avoiding being supported on output electricity
Malfunction or damage caused by when pressing through high.In the isolated power converting circuit or nothing using primary side adjustment (PSR) scheme
In line charge electricity power converting circuit, primary controller can not obtain the accurate information of output voltage in time；When output voltage is sent out
When raw over-voltage, primary controller cannot timely and accurately generate error protection.The isolated power converting circuit of PSR, which usually passes through, to be adopted
Feedback signal with an auxiliary winding or is directly obtained by primary side winding, as shown in Figure 1.By will be anti-on auxiliary winding Wa
Feedback signal FB and threshold signal are compared to judge whether output voltage Vo occurs over-voltage.But obtained from auxiliary winding
Feedback signal not can accurately reflect output voltage in some circumstances, such as in feelings such as dummy load (Dummy Load) open circuits
Condition.Therefore the overvoltage protection precision of this mode is poor, is failure to actuate when the generation overvoltage protection, to generate danger to load
Evil.
Utility model content
For one or more problems in the prior art, one of the utility model, which is designed to provide, eliminates above-mentioned mention
The secondary side control circuit of at least partly defect out and its isolated power converting circuit.
One aspect according to the present utility model provides a kind of secondary side control electricity for isolated power converting circuit
Road, which is characterized in that secondary side control circuit includes overvoltage protective module, and overvoltage protective module includes: the first comparison circuit, is had
First input end, the second input terminal and output end, wherein first input end coupling characterizes the output of isolated power converting circuit
The detection signal of voltage, the second input terminal couple first threshold signal；State detection circuit has input terminal and output end, shape
The input terminal of state detection circuit couples the secondary side signal of isolated power converting circuit；And pulse-generating circuit, have first
Input terminal, the second input terminal and output end, wherein the first input end of pulse-generating circuit couples the output of the first comparison circuit
End, the output end of the second input terminal coupling access status detection circuit of pulse-generating circuit, the output end coupling of pulse-generating circuit
The control terminal of secondary side rectifying tube.
In one embodiment, secondary side control circuit has first port and second port, and it is whole that first port couples secondary side
The source terminal or anode tap of flow tube, second port couple the drain electrode end or cathode terminal of secondary side rectifying tube；State detection circuit includes
The first input end of second comparison circuit, the second comparison circuit couples second port, the second input terminal coupling of the second comparison circuit
Connect second threshold signal.
In one embodiment, pulse-generating circuit include with door, wherein compared with the first input end of door coupling first
The output end of circuit couples the output end of the second comparison circuit with the second input terminal of door.
In one embodiment, secondary side control circuit has first port and second port, and it is whole that first port couples secondary side
The first end of flow tube, second port couple the second end of secondary side rectifying tube, and overvoltage protective module further comprises: sampling keeps electricity
Road, including sampling switch and capacitor, wherein the first end of sampling switch couples second port, and the second end of sampling switch couples electricity
Hold the first input end with the first comparison circuit；And sampling control module, the output end coupling sampling of sampling control module are opened
The control terminal of pass.
In one embodiment, overvoltage protective module further comprises: trigger circuit, the set input coupling of trigger circuit
The output end of the first comparison circuit is connect, the output end of trigger circuit couples pulse-generating circuit.
In one embodiment, secondary side control circuit further comprises: synchronous commutating control circuit, output synchronous rectification letter
Number；And door or door first input end coupling synchronous rectification signal or door the second input terminal coupling overvoltage protection letter
Number or the output end of door couple the control terminal of secondary side rectifying tube.
In one embodiment, the secondary rectifying tube when control circuit further comprises described secondary, secondary side rectifying tube include opening
Close transistor npn npn.
In one embodiment, secondary side control circuit further comprises second switch, wherein secondary side rectifying tube includes two poles
Pipe, second switch are connected across the both ends of rectifier diode.
Other side according to the present utility model provides a kind of secondary side control for isolated power converting circuit
Circuit, which is characterized in that isolated power converting circuit includes primary circuit and secondary circuit, primary circuit coupling input electricity
Pressure, primary circuit includes primary side winding and primary side switch；Secondary circuit includes vice-side winding and secondary side control circuit, vice-side winding
Composition transformer is coupled with primary side winding, secondary circuit provides the output voltage of isolated power converting circuit, wherein secondary side control
Circuit processed includes overvoltage protective module, and overvoltage protective module is detecting that it is predetermined that isolated power converting circuit output voltage is greater than
After threshold value and when primary side switch conducting, one pulse signal of output controls secondary side rectifying tube conducting；Primary circuit includes that overcurrent is protected
Protection circuit.
Another aspect according to the present utility model provides a kind of isolated power converting circuit, including above-mentioned pair
Side control circuit.
Over-voltage detection is put into secondary side electricity by pair side control circuit provided by the utility model and isolated power converting circuit
Road carries out, and triggers primary circuit guard mode by the way that secondary side rectifying tube is connected in a particular state, improves isolated power supply
The detection accuracy and reliability of the output voltage overvoltage protection of translation circuit.Other specific advantages of the utility model will be below
Specific embodiment in embodied.
Detailed description of the invention
Fig. 1 shows the isolated supply convertor overvoltage protection topology schematic diagram of correlation technique；
Fig. 2 shows the isolated power converting circuit block diagram representations according to an embodiment of the present invention；
Fig. 3 shows the isolated power converting circuit schematic diagram according to an embodiment of the present invention；
Fig. 4 shows a kind of secondary side rectifying tube control mode schematic diagram according to an embodiment of the present invention；
Fig. 5 shows the waveform diagram of signal in 3 circuit of corresponding diagram according to an embodiment of the present invention；
Fig. 6 shows the secondary side control circuit schematic diagram according to an embodiment of the present invention；
Fig. 7 shows the waveform diagram of signal in 6 circuit of corresponding diagram according to an embodiment of the present invention；
Identical label represents the same or similar component or composition in different schematic diagrames.
Specific embodiment
For a further understanding of the utility model, the utility model preferred embodiment is retouched below with reference to embodiment
It states, but it is to be understood that these descriptions are only the feature and advantage for further illustrating the utility model, rather than practical to this
The limitation of novel claim.
Just for several typical embodiments, the utility model is not limited merely to embodiment description for the description of the part
Range.Some technical characteristics in the combination of different embodiments, different embodiments are replaced mutually, and same or similar is existing
Some technical characteristics in technological means and embodiment are replaced mutually also in the range of the utility model describe and claim.
" coupling " in specification includes to be directly connected to, also comprising being indirectly connected with, as by electrically-conducting medi such as conductor
Connection, wherein the electrically-conducting medi can contain parasitic inductance or parasitic capacitance.May also include well known to a person skilled in the art
The connection on the basis of same or similar function purpose by other active devices or passive device can be achieved, such as by switch, with
With the connection of the circuits such as circuit or component.
Fig. 2 shows the isolated power converting circuit block diagram representations according to an embodiment of the present invention.It is isolated
Power converting circuit can also claim isolated switching circuit, isolated supply convertor etc..Isolated power converting circuit includes original
Side circuit 21 and secondary circuit 22.Primary circuit 21 receives input voltage vin.Primary circuit 21 includes primary side winding Wp and original
Side switch S1.Secondary circuit 22 includes vice-side winding Ws and secondary side control circuit 221.In the illustrated embodiment, secondary side control
Circuit 221 includes pair side rectifying tube S2.In another embodiment, the secondary control circuit 221 when rectifying tube S2 is not belonging to secondary
A part.Vice-side winding Ws and primary side winding Wp coupling composition transformer.By carrying out turn-on and turn-off to primary side switch S1
Input voltage vin by converting, is provided isolated power supply in secondary circuit 22 and become by switch motion, isolated power converting circuit
The output voltage Vo of circuit is changed, for driving load.
Secondary side control circuit 221 includes overvoltage protective module 222, and overvoltage protective module 222 is used in output voltage Vo mistake
Protection is provided to isolated power converting circuit when pressure.Overvoltage protective module 222 includes: the first comparison circuit 224, for comparing
The detection signal Vs and first threshold signal Vth1 of output voltage are characterized, the first comparison circuit 224 has first input end, second
Input terminal and output end, wherein first input end coupling characterizes the detection signal of the output voltage of isolated power converting circuit
Vs, the second input terminal couple first threshold signal Vth1；State detection circuit 225, based on secondary circuit 22 signal determine every
Transition state from formula power converting circuit, state detection circuit 225 have input terminal and output end, state detection circuit 225
Input terminal couple the secondary side signal of isolated power converting circuit, the output end of state detection circuit 225 provides state-detection
Signal；And pulse-generating circuit 226, comparison result and isolated power converting circuit based on the first comparison circuit 224
Selectively secondary side rectifying tube S2 is connected in output over-voltage protection signal to transition state, and pulse-generating circuit 226 is defeated with first
Enter end, the second input terminal and output end, wherein the first input end of pulse-generating circuit 226 couples the first comparison circuit 224
Output end, the output end of the second input terminal coupling access status detection circuit 225 of pulse-generating circuit 226, pulse-generating circuit 226
Output end coupling pair side rectifying tube S2 control terminal.Selectively output over-voltage protection signal includes the mistake for exporting effective status
Secondary side rectifying tube is connected in pressure protection signal.When overvoltage protection signal is invalid state, secondary side rectifying tube can be by synchronous rectification
Signal control.
In one embodiment, when the detection signal Vs for characterizing output voltage is greater than threshold signal Vth1, and it is isolated
When power converting circuit is in specific state, the overvoltage protection signal pulse that pulse-generating circuit 226 exports effective status will
Secondary side rectifying tube S2 conducting, for generating the signal that primary side can be identified significantly in primary circuit 21 and being protected in primary side triggering overcurrent
Shield.
Preferably, isolated power converting circuit includes inverse-excitation type voltage changer.Certainly, isolated power converting circuit
There can also be other topologys.
In a specific embodiment, output voltage of the overvoltage protective module 222 in isolated power converting circuit
Vo is greater than after first threshold and when detecting primary side switch S1 conducting, and output one pulse signal control pair side rectifying tube S2 is led
It is logical, so that primary circuit generates electric current point punching to trigger the overcurrent protection of primary circuit 21, and then realize overvoltage protection.
In this way, by secondary frontier inspection survey output voltage whether over-voltage, and when detecting over-voltage using every
Secondary side rectifying tube is connected in particular moment from formula power converting circuit, to generate the signal that can significantly identify in primary side to trigger
The error protection of primary circuit is avoided and is caused by auxiliary winding or primary side winding detection output voltage to realize overvoltage protection
Measurement inaccuracy problem.
Fig. 3 shows the isolated power converting circuit schematic diagram according to an embodiment of the present invention.Isolated power supply
The primary circuit of translation circuit includes primary side winding Wp, primary side switch S1 and primary-side-control circuit.Isolated power converting circuit
Secondary circuit include vice-side winding Ws, it is secondary in rectifying tube S2 and it is secondary while control circuit 221.The wherein first end of primary side winding Wp
Couple input power Vin, the first end of the second end coupling primary side switch S1 of primary side winding Wp, the second end coupling of primary side switch S1
It meets primary side reference ground PGND or primary side reference ground PGND is coupled by a sampling resistor.The first end of vice-side winding Ws is (as schemed institute
The different name end shown) coupling secondary side reference SGND (upper tube rectifying tube) or pair side rectifying tube S2 second end (down tube rectifying tube),
Vice-side winding Ws second end (Same Name of Ends as shown in the figure) coupling pair side rectifying tube S2 first end (upper tube rectifying tube) or every
Output end vo (down tube rectifying tube) from formula power converting circuit.The secondary first end in rectifying tube S2 rectifying tube S2 while secondary is
The source terminal of synchronous rectifier Shi Kewei pipe S2 is the anode tap that asynchronous rectified Guan Shike is pipe S2 in secondary side rectifying tube S2.It is secondary
The drain electrode end or cathode terminal of rectifying tube S2 when the second end of rectifying tube S2 can be secondary.In the first case, when secondary side rectifies
When pipe S2 is upper tube, the second end coupling of first end coupling secondary side reference the ground SGND, secondary side rectifying tube S2 of vice-side winding Ws every
Output end vo from formula power converting circuit.In second situation, when secondary side rectifying tube S2 is down tube, vice-side winding Ws's
Second end couples the output end vo of isolated power converting circuit, and the first end of secondary side rectifying tube S2 is with coupling secondary side reference
SGND.By carrying out the switch motion of turn-on and turn-off to primary side switch S1, isolated power converting circuit connects primary circuit
The input voltage vin of receipts provides the output voltage Vo of isolated power converting circuit in secondary circuit by transformation.Secondary side control
Circuit 221 includes overvoltage protective module 222, for providing guarantor to isolated power converting circuit in output voltage Vo over-voltage
Shield.Isolated power converting circuit can also further comprise rectification circuit, be used for alternating current such as commercial power rectification into direct current, and pass through
Input capacitance filtering provides DC bus-bar voltage.
In the embodiment shown in fig. 3, overvoltage protective module 222 includes the first comparison circuit 224, trigger circuit T1, shape
State detection circuit 225 and pulse-generating circuit 226.First comparison circuit 224 includes that comparator COM1 is used for output voltage Vo
Or the detection signal Vs of characterization output voltage Vo is compared with first threshold signal Vth1, and in output voltage Vo or output
The detection signal Vs of voltage makes the signal CP of trigger circuit T1 output effective status when being greater than threshold value Vth1.In the implementation of diagram
In example, trigger circuit T1 includes rest-set flip-flop, has set input S, the RESET input R and output end Q, wherein rest-set flip-flop
The output end of the set input S coupling comparison circuit COM1 of T1, the output end Q of rest-set flip-flop T1 provide signal CP.RS triggering
The RESET input R of device T1 can couple the source terminal of secondary synchronous rectifier S2.Trigger circuit T1 also can be considered that the first comparison is electric
The a part on road 224.State detection circuit 225 is used to determine the change of isolated power converting circuit based on the signal of secondary circuit
Change state.In the illustrated embodiment, state detection circuit 225 includes the second comparison circuit COM2, the second comparison circuit COM2
First input end receive rectifying tube both ends pressure difference signal Vds, specifically can be secondary synchronous rectifier drain source voltage,
The second input terminal of second comparison circuit COM2 couples second threshold signal Vth2.When pressure difference signal Vds is greater than second threshold
When Vth2, determine that primary side switch S1 is connected, so that the output end in state detection circuit 225 exports effective status signal Sta.
Any suitable method can be used in the both ends pressure difference signal Vds of detection pair side rectifying tube S2.Certainly, state detection circuit may also
With other detection methods and structure.Pulse-generating circuit 226 further comprise with door AND, with the first of door AND the input
The output end of end the first comparison circuit of coupling or trigger circuit T1 are coupled for receiving signal CP with the second input terminal of door AND
The output end of second comparison circuit COM2 is used for reception state signal Sta, is used for the output end coupling subsequent conditioning circuit of door AND
Generate overvoltage protection signal OVP.When the output signal CP of trigger circuit T1 and the output signal Sta of state detection circuit 225 are equal
When for effective status being such as high level, the signal of effective status is exported with door AND, pulse-generating circuit 226 exports effective shape
Secondary side rectifying tube S2 is connected in the overvoltage protection signal OVP of state.In one embodiment, the effective status of signal is high level shape
State, the invalid state of signal are low level state.In another embodiment, pulse-generating circuit includes and door AND.In this way,
Secondary side rectifying tube S2 and primary side switch S1 are simultaneously turned on, and the electric current IL on primary side winding Wp is by abnormal raising, to trigger primary side
The overcurrent protection of circuit stops the work of primary-side-control circuit or primary side switch S1, makes system stalls, realizes that over-voltage is protected
Shield.In the illustrated embodiment, primary circuit further comprises current foldback circuit, current foldback circuit when flow through primary side around
Output overcurrent protection signal OCPFault makes primary side switch S1 shutdown switch act or make when the electric current of group is more than third threshold value
Primary-side-control circuit stops working, and system is protected in the overcurrent protection by triggering primary side.In the illustrated embodiment, mistake
Current detection circuit includes third comparison circuit COM3, for that will characterize the detection signal Vcs and third threshold of primary side winding electric current IL
Value signal Vth3 is compared, and when current detection signal Vcs is greater than third threshold signal Vth3, comparison circuit COM3 output has
The overcurrent protection signal OCPFault of effect, for turning off primary side switch S1 or primary-side-control circuit being made to stop working.System can be
It is restarted after predetermined time.
In an embodiment as illustrated in figure 3, secondary side control circuit 221 further comprise synchronous commutating control circuit 32 and/or
Door OR.Synchronous commutating control circuit 32 is for exporting synchronous rectification signal SR.In one embodiment, when detecting that secondary side is whole
When flow tube flows through electric current, synchronous rectification signal SR is transformed to high level state.Or the first input end of door OR couples synchronous rectification
The control of the output end coupling pair side rectifying tube S2 of the second input terminal coupling overvoltage protection signal OVP or door of signal SR or door OR
End processed.When any one signal in synchronous rectification signal SR or overvoltage protection signal OVP be high level state when or door OR
The signal PWM of output is high level state, and secondary side rectifying tube S2 is connected.
The secondary rectifying tube S2 when control circuit 221 can further comprise described secondary.In one embodiment, secondary side rectifying tube
S2 includes switch type transistor, as metal oxide semiconductor field effect tube (MOSFET) or technotron (JFET) are managed.
Fig. 4 shows the secondary side rectifying tube D control mode of another kind according to an embodiment of the present invention.In the embodiment
In, the secondary rectifying tube when control circuit 221 does not include secondary, and further comprise a second switch S3, wherein secondary side rectifying tube packet
Include asynchronous rectifying tube such as diode D, the both ends that second switch S3 is connected across rectifier diode D are used for second switch S3 and whole
Stream diode D is connected in parallel.In this control, secondary side control circuit 221 can not include synchronous commutating control circuit and described
Or door.
Fig. 5 shows the signal waveforms in 3 circuit of corresponding diagram according to an embodiment of the present invention.Divide from top to bottom
Not Wei voltage sense signal Vs, signal CP, primary side switch driving signal DRV, synchronous rectification signal SR, rectifying tube pressure difference letter
Number Vds, state detection signal Sta, overvoltage protection signal OVP, secondary side rectifying tube driving signal PWM, primary side winding current detecting
Signal Vcs and primary side overcurrent protection signal OCPFault.Before time t 1, output voltage Vo is lower than threshold voltage, that is, exports
Voltage detection signal Vs is handed over lower than first threshold signal Vth1, primary side switch driving signal DRV and pair side synchronous rectification signal SR
For there is effective status, isolated power converting circuit is worked normally.It is higher than in time t1, output voltage Vo detection signal Vs
First threshold signal Vth1, the first comparison circuit COM1 export high level signal, and triggering trigger circuit T1 exports high level signal
CP.Become high level in time t2, primary side driving signal DRV, primary side switch S1 conducting, rectifying tube pressure difference signal Vds is greater than the
Two threshold value Vth2, status signal Sta are transformed to high level.Therefore overvoltage protection signal OVP exports high level pulse, secondary side driving
There is high level pulse in signal PWM.So that primary side switch S1 and pair side rectifying tube S2 are simultaneously turned on, the inspection of primary side winding electric current IL
It surveys signal Vcs and rises appearance point punching.It is higher than threshold signal Vth3 in time t3, primary side winding current signal Vcs, triggering overcurrent is protected
Shield signal OCPFault becomes effective status, to turn off primary side switch and/or primary-side-control circuit.
In this fashion, secondary circuit is when detecting output voltage over-voltage, by detecting the signal on secondary side as rectified
Pipe pressure difference signal Vds further detects the turn-on instant of primary side switch pipe, secondary side rectifying tube S2 is connected, to realize over-voltage
Protection control.And in this fashion, when secondary side rectifying tube S2 is switched on, the Over Current Protection System of automatic trigger primary side from
And realize overvoltage protection, without increasing additional detection circuit or control circuit in primary side, do not increase additional function in primary side
Energy and circuit, can be with existing various primary-side-control circuit compatibilities.
Fig. 6 shows the secondary side control circuit schematic diagram according to an embodiment of the present invention.Wherein secondary side control circuit
There is SRIC first port RGND and second port HV, first port RGND to couple the first end of pair side rectifying tube S2.First end
RGND can be the anode tap of the asynchronous rectifier diode of source terminal or secondary side of secondary synchronous rectifier S2.Second port HV coupling
The second end of secondary side rectifying tube S2.Second port HV can be the asynchronous rectification two of drain electrode end or secondary side of secondary synchronous rectifier S2
The cathode terminal of pole pipe.First port RGND can be used as the benchmark port of secondary side control circuit SRIC, in this way, second port HV electricity
Pressure and the signal inside pair side control circuit SRIC using the voltage of benchmark port RGND as ground level is referred to, are substantially
The difference signal of each signal and first port RGND voltage, wherein the value of second port HV signal is the secondary side both ends rectifying tube S2
Voltage difference, or the drain source voltage for synchronous rectifier S2.In one embodiment, secondary side rectifying tube is as upper tube, first port
RGND couples vice-side winding Ws, and second port HV couples the output end vo of secondary circuit.In another embodiment, secondary side rectification
Pipe is as down tube, and SGND, second port HV couple vice-side winding to first port RGND with coupling secondary side reference.
Secondary side control circuit SRIC includes overvoltage protective module 222.Secondary side control circuit SRIC can also further comprise same
Walk rectifier control circuit 32 and/or door OR.Wherein overvoltage protective module 222 includes the first comparison circuit COM1, state detection circuit
225 and pulse-generating circuit 226.Overvoltage protective module 222 can also further comprise trigger circuit T1 and with door AND, wherein touching
The input terminal of Power Generation Road T1 couples the output end of the first comparison circuit COM1, is respectively coupled to trigger circuit T1 with the input terminal of door
Output end and state detection circuit 225 output end.
Wherein state detection circuit 225 includes the second comparison circuit COM2, the first input end of the second comparison circuit COM2
Second port HV is coupled, the second input terminal of the second comparison circuit couples second threshold signal Vth2, when second port HV voltage
When greater than second threshold signal Vth2, state detection circuit exports effective value signal for allowing overvoltage protection signal that secondary side is connected
Rectifying tube S2.Here " permission " is only one of the condition for needing to meet, but does not represent and secondary side rectifying tube is connected immediately.Whether lead
Logical pair side rectifying tube will also see whether signal CP is effective status simultaneously.
Overvoltage protective module 222 can also further comprise that sampling hold circuit 61 is used to carry out the voltage of second port HV
Sampling and holding, make its output end signal reflect system output voltage Vo.Sampling hold circuit 61 includes sampling switch S3 and electricity
Hold C1, wherein the first end of sampling switch S3 couples second port HV, and the second end coupling capacitance C1 of sampling switch S3 is for mentioning
For characterizing the detection signal of output voltage and further coupling the first input end of the first comparison circuit COM1；First comparison circuit
The second input terminal of COM1 couples threshold signal Vth1.
The sampling hold circuit 61 of overvoltage protective module 222 can further comprise sampling control module 611, output end coupling
Connect the control terminal of sampling switch S3.In one embodiment, sampling control module 611 receives synchronous commutating control circuit 32 and exports
Synchronous rectification signal SR, for detect secondary side rectifying tube S2 terminate rectification predetermined time after be connected sampling switch S3.
In one embodiment, sampling control module 611 is connected after detecting that secondary side rectifying tube S2 terminates rectification 50-400 microsecond and adopts
Sample switch S3.Since after pair side rectifying tube S2 terminates the predetermined time of rectification, the second end of pair side control circuit SRIC at this time
Mouth HV voltage (the first port RGND voltage relative to secondary side control circuit SRIC) can correctly reflect isolated power conversion electricity
The actual output voltage Vo on road.
Fig. 7 shows the waveform diagram of 6 circuit of corresponding diagram according to an embodiment of the present invention.In time t1, letter
Number SR decline, synchronous rectifier stop rectification, and the time point t2 after predetermined time Δ t is sampled and protected to HV signal
It holds.Due to the rising of output voltage Vo, HV signal also rises in the time, therefore samples and keep signal VC in sampling time point t2
Also it increases, so that the detection signal VC of output voltage is more than first threshold signal Vth1, so that trigger circuit T1 output is high
The signal CP of level.In time point t3, DRV signal is increased, and primary side switch conducting, signal HV also rises to over second threshold letter
Number Vth2, so that the effective status for the status signal Sta output high level that state detection circuit 225 exports.So that over-voltage
Signal OVP is protected to export high level, the control signal PWM of secondary side rectifying tube is also high level, so that secondary side rectifying tube be connected
S2.So that primary side switch S1 and pair side rectifying tube S2 are simultaneously turned on, cause primary current IL overcurrent to trigger primary side overcurrent guarantor
Shield signal OCPFault is in effective status, to realize the protection to system.
In another embodiment, secondary side control circuit SRIC can further have third port, for coupling isolation
The output end vo of formula power circuit.Wherein the first port RGND of pair side control circuit SRIC can be used for coupling the pair of secondary circuit
Side is with reference to ground, and the second port HV of secondary side control circuit SRIC is for coupling vice-side winding, and secondary side rectifying tube is as down tube.This
When, the output voltage Vo of the direct sampled output of overvoltage protective module 222 is used for and first threshold signal Vth1 is compared, and
It does not need to include sampling hold circuit.
In one embodiment, whether the state of monitoring switch circuit includes monitoring the pressure difference at secondary side rectifying tube both ends to be greater than
Second threshold.When secondary side rectifying tube both ends pressure difference be greater than second threshold, illustrate primary side switch be connected.When monitoring output voltage
When greater than first threshold and monitoring that switching circuit state meets predetermined condition, such as when the pressure difference at secondary side rectifying tube both ends is greater than the
Secondary side rectifying tube is then connected in two threshold values, for generating fault-signal in primary side.When primary circuit senses fault-signal, make
Primary circuit stops working.In one embodiment, when secondary side rectifying tube and primary side switch simultaneously turn on, primary side winding electric current
There is point punching, it is by sensing primary side winding electric current greater than third threshold value, to trigger that primary circuit, which senses fault-signal,
The overcurrent protection mechanism of primary circuit realizes, thus realize by the overcurrent protection that triggers primary circuit come it is indirect realize every
Overvoltage protection from formula switching circuitry output.In this way, primary circuit without increase it is additional detect and control circuit, reduce
The complexity of primary circuit, and there is accurate over-voltage detection and over-voltage control simultaneously.In one embodiment, secondary side control electricity
The independent IC chip of Lu Weiyi.Primary-side-control circuit can also be an independent IC chip.In this way, it is only necessary to pair
Side control circuit chip, which is modified or replaced, can be realized the utility model without mating modification primary-side-control circuit chip
High accuracy high reliability secondary side output voltage overvoltage protection.
Here the description and application of the utility model are illustrative, are not wishing to for the scope of the utility model being limited in
It states in embodiment.The deformation and change of embodiments disclosed herein be it is possible, for the ordinary skill people of those this fields
The replacement of embodiment and equivalent various parts are well known for member.It should be appreciated by the person skilled in the art that not taking off
In the case where spirit or essential characteristics from the utility model, the utility model can in other forms, structure, arrangement, ratio,
And it is realized with other components, material and component.It, can be to this in the case where not departing from the scope of the utility model and spirit
In disclosed embodiment carry out other deformations and change.
Claims (10)
1. a kind of secondary side control circuit for isolated power converting circuit, which is characterized in that secondary side control circuit included
Protective module is pressed, overvoltage protective module includes:
First comparison circuit has first input end, the second input terminal and output end, wherein the isolation of first input end coupling characterization
The detection signal of the output voltage of formula power converting circuit, the second input terminal couple first threshold signal；
State detection circuit, has input terminal and output end, and the input terminal of state detection circuit couples isolated power conversion electricity
The secondary side signal on road；And
Pulse-generating circuit has first input end, the second input terminal and output end, wherein the first input of pulse-generating circuit
The output end of the first comparison circuit of end coupling, the output end of the second input terminal coupling access status detection circuit of pulse-generating circuit,
The output end of pulse-generating circuit couples the control terminal of secondary side rectifying tube.
2. pair side as described in claim 1 control circuit, it is characterised in that:
Secondary side control circuit has first port and second port, and first port couples the source terminal or anode of secondary side rectifying tube
End, second port couple the drain electrode end or cathode terminal of secondary side rectifying tube；
State detection circuit includes the second comparison circuit, and the first input end of the second comparison circuit couples second port, the second ratio
The second input terminal compared with circuit couples second threshold signal.
3. pair side as claimed in claim 2 control circuit, which is characterized in that pulse-generating circuit include with door, wherein with door
First input end couple the output end of the first comparison circuit, the output of the second comparison circuit is coupled with the second input terminal of door
End.
4. pair side as described in claim 1 control circuit, which is characterized in that secondary side control circuit has first port and second
Port, first port couple the first end of secondary side rectifying tube, and second port couples the second end of secondary side rectifying tube, overvoltage protection mould
Block further comprises:
Sampling hold circuit, including sampling switch and capacitor, wherein the first end of sampling switch couples second port, sampling switch
Second end coupling capacitance and the first comparison circuit first input end；And
Sampling control module, the control terminal of the output end coupling sampling switch of sampling control module.
5. pair side as described in claim 1 control circuit, which is characterized in that overvoltage protective module further comprises: triggering electricity
Road, the set input of trigger circuit couple the output end of the first comparison circuit, and the output end coupling pulse of trigger circuit generates
Circuit.
6. pair side as described in claim 1 control circuit, which is characterized in that secondary side control circuit further comprises:
Synchronous commutating control circuit exports synchronous rectification signal；And
Or the second input terminal of the first input end coupling synchronous rectification signal or door of door or door couples overvoltage protection signal, or
The output end of door couples the control terminal of secondary side rectifying tube.
7. pair side as described in claim 1 control circuit, which is characterized in that secondary when control circuit further comprises described secondary
Rectifying tube, secondary side rectifying tube includes switch type transistor.
8. pair side as described in claim 1 control circuit, which is characterized in that secondary side control circuit further comprises second opening
It closes, wherein secondary side rectifying tube includes diode, second switch is connected across the both ends of rectifier diode.
9. a kind of secondary side control circuit for isolated power converting circuit, which is characterized in that isolated power converting circuit
Including primary circuit and secondary circuit, primary circuit couples input voltage, and primary circuit includes primary side winding and primary side switch；It is secondary
The control circuit when circuit includes vice-side winding and is secondary, vice-side winding and primary side winding coupling composition transformer, secondary circuit mention
For the output voltage of isolated power converting circuit, wherein secondary side control circuit includes overvoltage protective module, overvoltage protective module
After detecting that isolated power converting circuit output voltage is greater than predetermined threshold and when primary side switch conducting, a pulse is exported
Signal controls secondary side rectifying tube conducting；Primary circuit includes current foldback circuit.
10. a kind of isolated power converting circuit, which is characterized in that including the described in any item secondary side controls of claim 1-9
Circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822002658.2U CN209389697U (en) | 2018-11-30 | 2018-11-30 | A kind of pair side control circuit and its isolated power converting circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822002658.2U CN209389697U (en) | 2018-11-30 | 2018-11-30 | A kind of pair side control circuit and its isolated power converting circuit |
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| CN209389697U true CN209389697U (en) | 2019-09-13 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109347066A (en) * | 2018-11-30 | 2019-02-15 | 深圳市必易微电子有限公司 | A kind of pair side control circuit and its isolated power converting circuit and over-voltage protection method |
| CN113162441A (en) * | 2020-01-22 | 2021-07-23 | 杭州必易微电子有限公司 | Isolated power supply circuit, primary and secondary side communication control circuit and control method |
-
2018
- 2018-11-30 CN CN201822002658.2U patent/CN209389697U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109347066A (en) * | 2018-11-30 | 2019-02-15 | 深圳市必易微电子有限公司 | A kind of pair side control circuit and its isolated power converting circuit and over-voltage protection method |
| CN113162441A (en) * | 2020-01-22 | 2021-07-23 | 杭州必易微电子有限公司 | Isolated power supply circuit, primary and secondary side communication control circuit and control method |
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Address after: Room 3303, block a, block 8, block C, Wanke Yuncheng phase III, Liuxin 4th Street, Xili community, Nanshan District, Shenzhen City, Guangdong Province Patentee after: Shenzhen Biyi Microelectronics Co., Ltd Address before: 518055 2 302, nine Xiang Ling new industrial zone, 4227 Xili Hu Road, Nanshan District, Shenzhen, Guangdong. Patentee before: SHENZHEN KIWI MICROELECTRONIC Co.,Ltd. |