CN105807125B - Zero cross detection circuit and Switching Power Supply comprising the circuit - Google Patents
Zero cross detection circuit and Switching Power Supply comprising the circuit Download PDFInfo
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- CN105807125B CN105807125B CN201610341535.4A CN201610341535A CN105807125B CN 105807125 B CN105807125 B CN 105807125B CN 201610341535 A CN201610341535 A CN 201610341535A CN 105807125 B CN105807125 B CN 105807125B
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- G01R19/175—Indicating the instants of passage of current or voltage through a given value, e.g. passage through zero
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Abstract
The present invention relates to a kind of zero cross detection circuits, including sample circuit unit, feedforward path circuit unit and comparison circuit unit.Sample circuit unit receives reference signal and zero cross signal, and the first output signal is exported according to reference signal, and the second output signal is exported according to zero cross signal；Feedforward path circuit unit receives the first output signal and the second output signal, and third output signal is exported according to the first output signal, and the 4th output signal is exported according to the second output signal；Comparison circuit unit exports first voltage signal according to the second output signal and third output signal, exports second voltage signal according to the first output signal and the 4th output signal, and control signal according to first voltage signal and second voltage signal output zero passage detection.First output signal and the second output signal are transmitted to comparison circuit unit with opposite stacked system, increase the input of comparison circuit unit, to improve the mutual conductance of comparison circuit unit, accelerate the transient response of zero cross detection circuit.
Description
Technical field
The present invention relates to electronic fields, and in particular to a kind of zero cross detection circuit and the Switching Power Supply comprising the circuit.
Background technology
Zero cross detection circuit can be because of the influence of response time and input offset voltage so that zero crossing judges lag.It is right
In common zero cross detection circuit, the response time can be even longer in tens nanoseconds, and offset voltage can be at ten millivolts or more.It is logical
Attempt the influence of counteracting response time in normal zero cross detection circuit using the method that lead is added, however it is inclined due to technique
Official post, which obtains the lead, cannot be completely counterbalanced by the influence of response time, therefore quick transient response can accurately just solve this and ask
Topic.
Fig. 1 is the application environment schematic diagram of zero cross detection circuit, i.e. synchronous rectification buck DC-DC circuit, due to zero passage
Point judges the reason of lag, and the inductive current that Switching Power Supply will appear pours in down a chimney phenomenon.2 be that zero passage phenomenon describes schematic diagram.It is this
It is more than to put state that situation, which can so that whole system is in a kind of, to make the efficiency of system drastically decrease.In addition, zero passage is examined
The accurate overturning for surveying signal determines the switching of whole system operating mode, and when not overturning, system works in PWM modulation mould
Formula, system works in PFM PSM modulating modes when a flip occurs, therefore the accurate judgement of zero cross detection circuit is to entire
Switch power supply system has vital effect.
Invention content
The technical problem to be solved in the present invention is, for the drawbacks described above of the prior art, provides a kind of zero passage detection electricity
Road and Switching Power Supply comprising the circuit overcome the influence of the response time of zero cross detection circuit, and zero crossing is judged
The defect of lag, by Optimization Design of Electronic Circuits, reduces the input imbalance of zero cross detection circuit while promoting transient response
Voltage further overcomes the defect that zero crossing judges lag.Solve what inductive current in switching power circuit poured in down a chimney simultaneously
Problem.
The technical solution adopted by the present invention to solve the technical problems is：
A kind of zero cross detection circuit, including sample circuit unit, feedforward path circuit unit and comparison circuit unit are provided,
The sample circuit unit receives reference signal and zero cross signal, and exports the first output signal according to reference signal, according to mistake
Zero-signal exports the second output signal；Feedforward path circuit unit receives first output signal and the second output letter
Number, and third output signal is exported according to first output signal, believed according to the 4th output of second output signal output
Number；Comparison circuit unit exports first voltage signal according to second output signal and the third output signal, according to institute
The first output signal and the 4th output signal output second voltage signal are stated, and according to the first voltage signal and described
Second voltage signal exports zero passage detection and controls signal.
Further, the sample circuit unit includes inputting to pipe circuit and load circuit, and the input is to pipe circuit
The reference signal and the zero cross signal are received, and the first current signal is exported according to the reference signal, according to the mistake
Zero-signal exports the second current signal；Load circuit is described inputs to pipe circuit supplies load, and according to first electric current
Signal exports the first output signal, and the second output signal is exported according to second current signal.
Further, the input includes current source, current mirror to pipe circuit and inputs to pipe, wherein the current source
Electric current is provided for the current mirror, the current mirror provides bias current for the input to pipe, described to input to pipe wherein
Two input terminals are connected with the current mirror, and in addition two input terminals receive the reference signal and the zero cross signal, and according to institute
It states reference signal and exports first current signal, second current signal is exported according to the zero cross signal.
Further, the current mirror includes two field-effect tube.
Further, two field-effect tube is p-type field-effect tube.
Further, the input includes the first field-effect tube and the second field-effect tube, first field-effect tube to pipe
Source electrode connect the current mirror, grid connects the reference signal, and drain electrode exports first current signal；Described second
The source electrode of effect pipe connects the current mirror, and grid connects the zero cross signal, and drain electrode exports second current signal.
Further, first field-effect tube and second field-effect tube are low-pressure type devices.
Further, first field-effect tube and second field-effect tube are p-type field-effect tube.
Further, the load circuit includes two resistance, and two resistance is respectively connected to first field-effect tube
With the drain electrode of second field-effect tube, the value of the resistance value of the resistance makes first field-effect tube and second described
The input of effect pipe is operated in subthreshold region to pipe.
Further, the load circuit includes first resistor and second resistance, and the first resistor is first electricity
It flows signal and load is provided, to export first output signal, the second resistance provides load for second current signal,
To export second output signal.
Further, the feedforward path circuit unit include the first feed forward circuit and the second feed forward circuit, described first
Feed forward circuit receives first output signal, and exports the third output signal according to first output signal, described
Third output signal is equal to first output signal；The second feed forward circuit reception, second output signal, and according to
Second output signal exports the 4th output signal, and the 4th output signal is equal to second output signal.
Further, first feed forward circuit and second feed forward circuit are source follower circuits.
Further, the comparison circuit unit includes consolidation circuit and comparison circuit.The consolidation circuit is according to
Second output signal and the third output signal export the first voltage signal, according to first output signal and described
4th output signal exports the second voltage signal, and the first voltage signal and the second voltage signal merge, with defeated
Go out voltage and merges signal；Comparison circuit merges signal output zero passage detection according to the voltage and controls signal.
Further, the consolidation circuit includes receiving to pipe and current mirror load.Described receive receives to the first of pipe
End receives second output signal and the third output signal, and output current signal；The reception connects to the second of pipe
Receiving end receives first output signal and the 4th output signal, and exports the second voltage signal；The electric current letter
Number the first voltage signal is exported after the current mirror load and is merged with the second voltage signal, described in output
Voltage merges signal.
Further, described receive includes third field-effect tube and the 4th field-effect tube, the third field-effect tube to pipe
Grid connect the third output signal, source electrode connects second output signal, and drain electrode exports the current signal；It is described
The grid of 4th field-effect tube connects the 4th output signal, and source electrode connects first output signal, drains described in output
Second voltage signal.
Further, when the voltage, which merges signal, is less than the half of supply voltage, the high electricity of comparison circuit output
It is flat；When the voltage, which merges signal, is more than or equal to the half of supply voltage, the comparison circuit exports low level.
Further, the comparison circuit is inverter circuit.
The present invention also provides a kind of Switching Power Supplies, using any one zero passage detection electricity as described in claim 1 to 17
Road is used for the zero passage detection of the Switching Power Supply.
The beneficial effects of the present invention are, by design feedforward path single channel unit, improve comparison circuit unit across
It leads, to accelerate the transient response of zero cross detection circuit.Simultaneously to reduce input offset voltage, using low-voltage device as input
To pipe, and appropriate load value is set so that input is operated in subthreshold region to pipe, improves the output gain of sample circuit unit,
To reduce the equivalent input noise voltage of comparison circuit unit, and then reduce the input imbalance electricity of zero cross detection circuit
Pressure.Accelerate transient state it is corresponding while keep low input offset voltage, solve zero cross detection circuit zero crossing judge it is stagnant
Defect afterwards.Zero cross detection circuit using the present invention solves the problems, such as that inductive current pours in down a chimney in switching power circuit, is promoted
The efficiency of Switching Power Supply.
Description of the drawings
Present invention will be further explained below with reference to the attached drawings and examples, in attached drawing：
Fig. 1 is the application environment schematic diagram of zero cross detection circuit；
Fig. 2 is that zero passage phenomenon describes schematic diagram；
Fig. 3 is the circuit block diagram of the zero cross detection circuit 300 of one embodiment of the invention；
Fig. 4 is the physical circuit of the zero cross detection circuit 400 of one embodiment of the invention；
Specific implementation mode
In conjunction with attached drawing, elaborate to presently preferred embodiments of the present invention.
Fig. 3 is the circuit block diagram of the zero cross detection circuit 300 of one embodiment of the invention.Zero cross detection circuit 300 can be by adopting
Sample circuit unit 302, feedforward path circuit unit 304 and comparison circuit unit 306 form.Wherein, sample circuit unit 302 connects
Reference signal and zero cross signal are received, and the first output signal is exported according to reference signal, according to the second output of zero cross signal output
Signal, wherein zero cross signal can be the voltage signal of LX points in Fig. 1.Feedforward path circuit unit 304 receives the first output signal
With the second output signal, and third output signal is exported according to the first output signal, it is the 4th defeated according to the output of the second output signal
Go out signal, wherein the first output signal is equal with third output signal, and the second output signal is equal with the 4th output signal.Than
The first output signal and the second output signal are received compared with circuit unit 306, while receiving third output signal and the 4th output letter
Number, and first voltage signal is exported according to the second output signal and third output signal, it is defeated according to the first output signal and the 4th
Go out signal output second voltage signal, signal is controlled according to first voltage signal and second voltage signal output zero passage detection.It needs
It is noted that zero cross detection circuit is alternatively referred to as zero-crossing comparator.In addition, some zero cross detection circuits are in comparison circuit unit
It further include digital circuit after 306.
Second output signal of sample circuit unit 302 is directly transferred to the first receiving terminal of comparison circuit unit 306, together
When, the third output signal of feedforward path circuit unit 304 is transmitted to the first receiving terminal of comparison circuit unit 306.Sampling electricity
First output signal of road unit 302 is directly transferred to the second receiving terminal of comparison circuit unit 306, meanwhile, feedforward path electricity
4th output signal of road unit 304 is transmitted to the second receiving terminal of comparison circuit unit 306.Wherein, feedforward path circuit list
The third output signal of member 304 is equal, feedforward path circuit unit with the first output signal of sample circuit unit 302
304 the 4th output signal is equal with the second output signal of sample circuit unit 302, so sample circuit unit 302
The first output signal and the second output signal the first receiving terminal of comparison circuit unit 306 is transmitted to opposite stacked system
With the second receiving terminal, the input signal of comparison circuit unit is increased, to improve the mutual conductance of comparison circuit unit 306, is carried
The high transient response of zero cross detection circuit.
Fig. 4 is the physical circuit figure of the zero cross detection circuit 400 of one embodiment of the invention.
In one embodiment, sample circuit unit 402 may include input to pipe circuit and load circuit, and input is to pipe electricity
Road receives reference signal and zero cross signal, and exports the first current signal according to reference signal, and second is exported according to zero cross signal
Current signal.Load circuit is input to pipe circuit supplies load, and according to input to the first current signal of pipe circuit output
The first output signal is exported, the second output signal is exported to the second current signal of pipe circuit output according to input.
In one embodiment, input may include current source, current mirror and input to pipe to pipe circuit, and current source is electric current
Mirror provides electric current, and current mirror provides bias current for input to pipe, inputs and connects the defeated of current mirror to wherein two input terminals of pipe
Outlet, in addition two input terminals receive reference signal and zero cross signal, and export the first current signal according to reference signal, according to mistake
Zero-signal exports the second current signal.
In one embodiment, current mirror may include two field-effect tube.In other embodiments, it is possible to use Liang Sanji
Pipe forms current mirror, only the connection type slight changes of circuit, you can realizes the effect of this current mirror in the present invention.
In one embodiment, since the input signal of zero cross detection circuit is the voltage signal of zero crossings, and N-type field
Effect pipe compared with p-type field-effect tube, it is required that input voltage it is higher, current mirror can be by two p-type field-effect tube M11 and M12
Current mirror is formed, M11 is connected with the grid of M12, and the source electrode of M11 and M12 connect power supply, and the drain electrode of M11 connects current source, M12's
Drain electrode connection input provides bias current to pipe, for input to pipe.
In one embodiment, input may include the first field-effect tube M1 and the second field-effect tube M2 to pipe.First effect
Should pipe M1 source electrode connect current mirror, grid connect reference signal, according to reference signal drain output the first current signal；Second
The source electrode of field-effect tube M2 connects current mirror, and grid connects zero cross signal, and second electric current is exported according to zero cross signal drain electrode
Signal.In other embodiments, input may include pipe to use two triodes, and the Misalignment Characteristics of triode are than field-effect tube
It is good, so being inputted to pipe using triode, the input offset voltage of zero cross detection circuit can be further decreased.But triode
Cost be higher than metal-oxide-semiconductor.
In one embodiment, low-pressure type device can be used in the first field-effect tube M1 and the second field-effect tube M2.Specific
In embodiment, since the low incoming level of zero cross detection circuit is unfavorable for the first order and uses larger ruler due to the limitation of level
Very little device realizes the effect of low imbalance, and the Misalignment Characteristics of modern CMOS processes mesolow device are far better than high-voltage device
Part using identity unit area, can be dropped so low-voltage device can be used as inputting to pipe using low-voltage device
Low input offset voltage.
In one embodiment, two p-type field-effect tube can be used in the first field-effect tube M1 and the second field-effect tube M2, M1's
Grid receives reference signal, and the grid of M2 receives zero cross signal, and M1 connects the output end of current source with the source electrode of M2, M1 and M2's
Drain electrode connection load circuit.Because the input voltage needed for p-type field-effect tube M1 and M2 is than the input electricity needed for N-type field-effect tube
It forces down, it, can be with so p-type field-effect tube M1 and M2 are particularly suited for the input of the sample circuit unit of zero cross detection circuit to pipe
So that zero passage detection is more acurrate.
In one embodiment, load circuit may include that two resistance, two resistance are respectively connected to the first field-effect tube and
The drain electrode of two field-effect tube may make the first field-effect tube and the second field-effect tube to be operated in Asia by the way that suitable resistance value is arranged
Threshold area, so that the first field-effect tube and the current signal of the second field-effect tube output have larger gain, to reduce
The equivalent input noise voltage of comparison circuit unit 306 further reduces the input offset voltage of zero cross detection circuit.Simultaneously
Due to the influence of load circuit so that the output node parasitic poles of sample circuit unit are very high, and time constant is low, so adopting
Influence of the sample circuit unit to the response time of zero cross detection circuit can be ignored.
In one embodiment, load circuit can be made of first resistor R1 and second resistance R2, wherein input is to pipe
The output end of circuit is connected with first resistor R1 and second resistance R2 respectively, inputs the first current signal export to pipe and passes through the
One resistance R1 inputs the second current signal exported to pipe by second resistance R2 to export second to export the first output signal
Output signal.
In one embodiment, feedforward path circuit unit 404 may include the first feed forward circuit and the second feed forward circuit, the
One feed forward circuit receives the first output signal of sample circuit unit 402, and exports third output letter according to the first output signal
Number；Second feed forward circuit receives the second output signal of sample circuit unit 402, and defeated according to the output the 4th of the second output signal
Go out signal, wherein third output signal is equal with the first output signal, and the 4th output signal is equal with the second output signal.?
In specific implementation mode, it is electric that the first output signal and the second output signal of sample circuit unit 402 are also directly transferred to comparison
Road unit 406, i.e. the first output signal and the second output signal of sample circuit unit 402 are passed with opposite stacked system respectively
Transport to the first receiving terminal and the second receiving terminal of comparison circuit unit 406 so that the output signal of sample circuit unit 402 is with two
Form again is transmitted to comparison circuit unit 406, improves the mutual conductance of comparison circuit unit 406, and then accelerate zero passage detection
The response time of circuit.
In one embodiment, the first feed forward circuit of feedforward path circuit unit 404 and the second feed forward circuit can be
Source follower circuit.In other embodiments, can use with circuit of the source follower circuit with phase same-action come replace source with
Device circuit, only the connection type of circuit make a little effects for changing and source follower circuit in the present invention can be realized.
In a specific embodiment, source follower circuit can be made of two field-effect tube, i.e. M3 in Fig. 4 and M5 compositions first
Source follower circuit, M4 and M6 form the second source follower circuit.The source electrode of wherein field-effect tube M5 connects power supply, the grid connection of M5
The drain electrode of current source, M5 is connected with the source electrode of field-effect tube M3 (source follower), and the of the grid of M3 connection sample circuit unit 302
The source electrode of one output signal, the grounded drain of M3, M3 exports third output signal, third output signal and the first output signal phase
Deng.The source electrode of field-effect tube M6 connects power supply, and M6 grids connect current source, the source electrode of M6 drain electrode and field-effect tube M4 (source follower)
It is connected, the second output signal of the grid connection sample circuit unit 302 of M4, the grounded drain of M4, the source electrode output the 4th of M4
Output signal, the 4th output signal are equal with the second output signal.In other embodiments, it can be formed using triode
Source follower circuit, only the connection type of circuit make a little effects for changing and source follower circuit in the present invention can be realized.
In one embodiment, comparison circuit unit 406 can be made of consolidation circuit and comparison circuit, and consolidation circuit receives
The first output signal and the second output signal of sample circuit unit 402, while receiving the third of feedforward path circuit unit 404
Output signal and the 4th output signal, and first voltage signal is exported according to the second output signal and third output signal, according to
First output signal and the 4th output signal export second voltage signal, and first voltage signal and second voltage signal merge, with
Output voltage merges signal.Comparison circuit merges signal output zero passage detection according to voltage and controls signal.Wherein, third output letter
Number equal with the first output signal, the 4th output signal is equal with the second output signal, so that sample circuit unit 402
First output signal and the second output signal are transmitted to comparison circuit unit 406 with opposite stacked system, and it is electric to increase comparison
The mutual conductance of road unit 406, to improve the transient response of zero cross detection circuit.
In one embodiment, consolidation circuit may include receiving to pipe and current mirror load, receives and is received to the first of pipe
According to the first output signal and the second output signal output current signal, current signal exports first after current mirror load at end
Voltage signal；It receives and second voltage signal is exported according to third output signal and the 4th output signal to the second receiving terminal of pipe；
First voltage signal merges with second voltage signal, and output voltage merges signal.
In one embodiment, it receives and third field-effect tube M7 and the 4th field-effect tube M8 may include to pipe.It imitates third field
Should pipe M7 grid connection source follower M3 source electrode, i.e. third output signal, source electrode connects the drain electrode of field-effect tube M2, i.e., second
Output signal, drain output current signal；The grid of 4th field-effect tube M8 connects source follower M4 source electrodes, i.e., the 4th output letter
Number, source electrode connects the drain electrode of field-effect tube M1, i.e. the first output signal, drain electrode output second voltage signal.
In other embodiments, triode can be used as receiving to pipe, only the connection type of circuit is not
Together, the effect of third field-effect tube and the 4th field-effect tube in the present invention can be also realized.
In one embodiment, current mirror load may include two field-effect tube M9 and M10, and load is provided to pipe to receive.
In a specific embodiment, the source electrode of M9 and M10 connects power supply, and M9 is connected with the grid of M10, the drain electrode of the drain electrode connection M7 of M9,
The drain electrode of M10 is connected with the drain electrode of M8.Under the action of current mirror load, the current signal of M7 drain electrode outputs is negative by current mirror
First voltage signal, the second voltage signal merging of first voltage signal and M8 outputs, with output voltage are exported after carrying M9 and M10
Merge signal.In other embodiments, triode composition current mirror load may be used, only the connection type of circuit is not
Together, the effect of current mirror load in the present invention equally may be implemented.
In one embodiment, when voltage, which merges signal, is less than the half of supply voltage, comparison circuit exports high level,
I.e. zero passage detection controls signal；When voltage, which merges signal, is more than or equal to the half of supply voltage, comparison circuit exports low level.
In other embodiments, can the parameter of element in different comparison circuits be designed according to actual needs, it is electric to obtain comparison
The different roll over condition on road.
In one embodiment, comparison circuit can be inverter circuit M13 and M14.The source electrode of M13 connects power supply, grid
Pole connects voltage and merges signal, the source electrode ground connection of M14, and grid connects voltage and merges signal, and M13 is connected with the drain electrode of M14, as
Output end.When voltage, which merges signal, is less than the half of supply voltage, M13 conductings, M14 cut-offs, phase inverter output high level, i.e.,
Zero passage detection controls signal；When voltage, which merges signal, is more than or equal to the half of supply voltage, M13 cut-offs, M14 conductings, reverse phase
Device exports low level.In other embodiments, triode can also be selected to form phase inverter.In yet another embodiment, may be used
To use Schmidt trigger as comparison circuit, it only need to simply change the connection type of circuit.
The present invention also provides a kind of Switching Power Supply, Switching Power Supply contains any of present invention zero cross detection circuit.
Since zero cross detection circuit improves transient response speed, while also reducing input offset voltage so that switching power circuit
Afterflow power tube can be closed in the course of work in time, the phenomenon that pouring in down a chimney so as to avoid inductive current in Switching Power Supply, in turn
Improve the efficiency of Switching Power Supply.
The concrete operating principle of zero cross detection circuit 400 shown in Fig. 4 is as follows：
Sample circuit unit 402 includes current source, current mirror (M11 and M12 compositions), input to pipe M1 and M2 and resistance
R1, R2, wherein M1, M2, M11, M12 are p-type field-effect tube.Current source, current mirror and input constitute input pair to pipe M1 and M2
Pipe circuit, resistance R1 and R2 form load circuit.Feedforward path circuit unit 404 include two source follower circuits, wherein M3 and
M5 forms the first source follower circuit, and M4 and M6 form the second source follower circuit, and wherein M3, M5, M4, M6 is p-type field-effect tube.
Comparison circuit unit 406 includes the field-effect tube M7 and M8 for receiving signal, current mirror load (M9 and M10 compositions), phase inverter
(M13 and M14 compositions), wherein M7, M8, M14 are N-type field-effect tube, and M9, M10, M13 are p-type field-effect tube, N-type field-effect tube
M7 and M8 constitutes consolidation circuit with current mirror load.
The grid of M1 in sample circuit unit 402 connects reference signal, and source electrode is connected with the output end of current mirror, and drain electrode is defeated
Go out the first current signal；The grid of M2 in sample circuit unit 402 takes over zero-signal, i.e. the voltage of LX points in Fig. 2, source electrode with
The output end of current mirror is connected, drain electrode the second current signal of output.Wherein, M1 and M2 uses low-pressure type device, can reduce sampling
The input offset voltage of circuit unit 402.In addition, by the way that suitable resistance value is arranged to resistance R1 and R2 so that M1 and M2 work
In subthreshold region, so that first output signal of the M1 outputs with more large gain in sample circuit unit 402, M2 output tools
The second output signal for having more large gain, reduces the equivalent input noise voltage of comparison circuit unit 406, to reduce
The input offset voltage of zero detection circuit.
The first source follower circuit in feedforward path single channel unit 404 receives the first output signal, and exports third output
Signal, wherein third output signal is equal with the first output signal.The second source follower electricity in feedforward path single channel unit 404
Road receives the second output signal, and exports the 4th output signal, wherein the 4th output signal is equal with the second output signal.
The source electrode of M7 in comparison circuit unit 406 receives the second output signal of sample circuit unit 402, the grid of M7
The third output signal of feedforward path circuit unit 404 is received, the drain electrode output current signal of M7, the current signal is through overcurrent
Mirror exports first voltage signal after loading M9 and M10；The source electrode of M8 in comparison circuit unit 406 receives sample circuit unit
402 the first output signal, the grid of M8 receive the 4th output signal of feedforward path circuit unit 404, the drain electrode output of M8
Second voltage signal, first voltage signal merge with the second voltage signal that M8 is exported, to generate voltage merging signal and pass
It is defeated by phase inverter M13 and M14, when voltage, which merges signal, is less than the half of supply voltage, M13 conductings, M14 cut-offs, phase inverter
High level is exported, i.e. zero passage detection controls signal.Wherein, third output signal is equal with the first output signal, the 4th output letter
It is number equal with the second output signal, so the first output signal and the second output signal of sample circuit unit 402 are respectively with phase
Anti- stacked system is transmitted to two receiving terminals of comparison circuit unit 406, increases the input letter of comparison circuit unit 406
Number, the mutual conductance of comparison circuit unit 406 is improved, to which the transient state for accelerating zero cross detection circuit is corresponding,
It should be understood that the above embodiments are merely illustrative of the technical solutions of the present invention, rather than its limitations, to ability
It for field technique personnel, can modify to technical solution described in the above embodiment, or special to which part technology
Sign carries out equivalent replacement；And all such modifications and replacement, it should all belong to the protection domain of appended claims of the present invention.
Claims (18)
1. a kind of zero cross detection circuit, which is characterized in that including：
Sample circuit unit exports the first output signal for receiving reference signal and zero cross signal according to the reference signal,
The second output signal is exported according to the zero cross signal；
Feedforward path circuit unit receives first output signal and second output signal, and defeated according to described first
Go out signal output third output signal, the 4th output signal is exported according to second output signal；
Comparison circuit unit exports first voltage signal according to second output signal and the third output signal, according to
First output signal and the 4th output signal export second voltage signal, and according to the first voltage signal and institute
State second voltage signal output zero passage detection control signal.
2. zero cross detection circuit as described in claim 1, which is characterized in that the sample circuit unit includes：
Input is to pipe circuit, for receiving the reference signal and the zero cross signal, and according to reference signal output the
One current signal exports the second current signal according to the zero cross signal；And load circuit, for being inputted to pipe circuit to be described
Load is provided, and first output signal is exported according to first current signal, is exported according to second current signal
Second output signal.
3. zero cross detection circuit as claimed in claim 2, which is characterized in that the input includes to pipe circuit：Current source, electricity
Mirror and input are flowed to pipe；
Wherein, the current source provides electric current for the current mirror；The current mirror provides bias current for the input to pipe；
The input is connected to wherein two input terminals of pipe with the current mirror, and in addition two input terminals receive the reference signal and described
Zero cross signal, and first current signal is exported according to the reference signal, export described second according to the zero cross signal
Current signal.
4. zero cross detection circuit as claimed in claim 3, which is characterized in that the current mirror includes two field-effect tube.
5. zero cross detection circuit as claimed in claim 4, which is characterized in that two field-effect tube is p-type field-effect tube.
6. zero cross detection circuit as claimed in claim 3, which is characterized in that the input includes to pipe：First field-effect tube
With the second field-effect tube；
Wherein, the source electrode of first field-effect tube connects the current mirror, and grid connects the reference signal, drain electrode output institute
State the first current signal；The source electrode of second field-effect tube connects the current mirror, and grid connects the zero cross signal, drain electrode
Export second current signal.
7. zero cross detection circuit as claimed in claim 6, which is characterized in that first field-effect tube and second effect
Should pipe be low-pressure type device.
8. zero cross detection circuit as claimed in claim 6, which is characterized in that first field-effect tube and second effect
Should pipe be p-type field-effect tube.
9. zero cross detection circuit as claimed in claim 6, which is characterized in that the load circuit include two resistance, described two
Resistance is respectively connected to the drain electrode of first field-effect tube and second field-effect tube, and the value of the resistance value of the resistance makes
It obtains first field-effect tube and second field-effect tube is operated in subthreshold region.
10. zero cross detection circuit as claimed in claim 2, which is characterized in that the load circuit includes：First resistor and
Two resistance；
Wherein, the first resistor provides load for first current signal, to export first output signal, described
Two resistance provide load for second current signal, to export second output signal.
11. zero cross detection circuit as described in claim 1, which is characterized in that the feedforward path circuit unit includes：
First feed forward circuit exports the third for receiving first output signal, and according to first output signal
Output signal, the third output signal are equal to first output signal；
Second feed forward circuit exports the described 4th for receiving second output signal, and according to second output signal
Output signal, the 4th output signal are equal to second output signal.
12. zero cross detection circuit as claimed in claim 11, which is characterized in that before first feed forward circuit and described second
Current feed circuit is source follower circuit.
13. zero cross detection circuit as described in claim 1, which is characterized in that the comparison circuit unit includes：
Consolidation circuit, for exporting the first voltage signal according to second output signal and the third output signal,
Export the second voltage signal according to first output signal and the 4th output signal, the first voltage signal with
The second voltage signal merges, and merges signal with output voltage；And
Comparison circuit controls signal for merging signal output zero passage detection according to the voltage.
14. zero cross detection circuit as claimed in claim 13, which is characterized in that the consolidation circuit includes receiving to pipe and electricity
Flow mirror load：
Described receive receives second output signal and the third output signal, and output current to the first receiving terminal of pipe
Signal, the current signal export the first voltage signal after the current mirror load；
Described receive receives first output signal and the 4th output signal to the second receiving terminal of pipe, and described in output
Second voltage signal；
The first voltage signal merges with the second voltage signal, merges signal to export the voltage.
15. zero cross detection circuit as claimed in claim 14, which is characterized in that the reception includes to pipe：Third field-effect
Pipe and the 4th field-effect tube；
The grid of the third field-effect tube connects the third output signal, and source electrode connects second output signal, drain electrode
The current signal is exported, the current signal exports the first voltage signal after the current mirror load；
The grid of 4th field-effect tube connects the 4th output signal, and source electrode connects first output signal, drain electrode
Export the second voltage signal.
16. zero cross detection circuit as claimed in claim 13, which is characterized in that be less than power supply electricity when the voltage merges signal
When the half of pressure, the comparison circuit exports high level；When the voltage, which merges signal, is more than or equal to the half of supply voltage,
The comparison circuit exports low level.
17. zero cross detection circuit as claimed in claim 13, which is characterized in that the comparison circuit is inverter circuit.
18. a kind of Switching Power Supply, which is characterized in that using any one zero cross detection circuit as described in claim 1 to 17, use
In the zero passage detection of the Switching Power Supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610341535.4A CN105807125B (en) | 2016-05-20 | 2016-05-20 | Zero cross detection circuit and Switching Power Supply comprising the circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610341535.4A CN105807125B (en) | 2016-05-20 | 2016-05-20 | Zero cross detection circuit and Switching Power Supply comprising the circuit |
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| CN105807125A CN105807125A (en) | 2016-07-27 |
| CN105807125B true CN105807125B (en) | 2018-10-30 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201610341535.4A Active CN105807125B (en) | 2016-05-20 | 2016-05-20 | Zero cross detection circuit and Switching Power Supply comprising the circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111987971A (en) * | 2020-08-17 | 2020-11-24 | 李雁鸣 | Automatic control system and control method for improving load stability |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4959558A (en) * | 1988-03-31 | 1990-09-25 | U.S. Philips Corporation | Circuit arrangement for detecting cross-over by an alternating voltage of a fixed reference voltage level |
| CN201846243U (en) * | 2010-11-18 | 2011-05-25 | Bcd半导体制造有限公司 | Zero-crossing detection circuit of switching power supply |
| CN103760408B (en) * | 2014-01-26 | 2017-02-15 | 矽力杰半导体技术(杭州)有限公司 | Zero cross detection circuit |
| CN103929048B (en) * | 2014-04-29 | 2016-04-20 | 中国科学院上海微系统与信息技术研究所 | A kind of zero cross detection circuit of Switching Power Supply |
| CN104467364B (en) * | 2014-12-15 | 2017-03-01 | 矽力杰半导体技术(杭州)有限公司 | A kind of zero cross detection circuit and Switching Power Supply |
| CN204595077U (en) * | 2015-05-06 | 2015-08-26 | 胡爽禄 | A kind of zero cross detection circuit with phase compensation |
| CN105406444A (en) * | 2015-11-20 | 2016-03-16 | 芜湖锐芯电子科技有限公司 | Zero-cross detection circuit |
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