CN206180848U - Switching power supply and control circuit thereof - Google Patents
Switching power supply and control circuit thereof Download PDFInfo
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- CN206180848U CN206180848U CN201621134639.XU CN201621134639U CN206180848U CN 206180848 U CN206180848 U CN 206180848U CN 201621134639 U CN201621134639 U CN 201621134639U CN 206180848 U CN206180848 U CN 206180848U
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Abstract
The utility model discloses a switching power supply and control circuit thereof. Control circuit includes: adjusting module for carry out the comparison in order to produce a control voltage with switching signal's cycle with the reference cycle, current source module is used for the basis a control voltage produces a charging current, pulse signal produces the module, be used for with a charging current converts the switch conduction into or turn -offs time signal, drive module is used for the basis switch conduction or shutoff time signal produce switching signal to what control switch managed switches on and turn -offs, and time measured module, be used for the basis switching signal obtain the time parameter and according to the time parameter produces cycle conditioning signal, wherein, the adjusting module basis cycle conditioning signal adjusts reference cycle, thus adjust switching signal's cycle. This control circuit utilizes the dynamic control compensation in reference cycle to turn -off time change to realize wide input and output voltage range.
Description
Technical field
This utility model belongs to electric and electronic technical field, more particularly, to Switching Power Supply and its control circuit.
Background technology
Switching Power Supply is the turn-on and turn-off using switching signal controlling switch pipe, by the charging to energy-storage travelling wave tube and is put
Electricity maintains the power circuit of stable output.In Switching Power Supply, control circuit produces switching signal, with the conducting of controlling switch pipe
And shut-off.The ON time of switching tube accounts for the ratio of whole switch periods and is referred to as dutycycle.The input voltage of Switching Power Supply, output
Specific relation is there is between voltage and dutycycle.Therefore, in input voltage fluctuation, can be adjusted by the feedback of dutycycle
Section obtains stable output voltage, and the voltage regulation limits of Switching Power Supply are limited by duty cycle range.
The constant time control method of Switching Power Supply include permanent conducting control method (Constant On Time, COT) and
Perseverance shut-off control method (Constant Off Time, COT).Wherein, permanent conducting control method is by the control Switching Power Supply
Switching tube turned on constant time, realization converts input voltage into output voltage with driving load, perseverance shut-off controlling party
Method is turned off by the switching tube of the control Switching Power Supply with the constant time, realization convert input voltage into output voltage with
Driving load.Need the regular hour to examine generally, due to the operational amplifier in control circuit, comparator and drive module etc.
Survey and action, therefore, the turn-off time of switching signal should be more than or equal to the minimum turn-off time, and the ON time of switching signal should
Should be more than or equal to minimum ON time.
Due to the presence of minimum turn-off time, in permanent conducting control method, the maximum of dutycycle is restricted；Due to
The presence of minimum ON time, in permanent shut-off control method, the minima of dutycycle is restricted.Therefore Switching Power Supply is defeated
Enter voltage to be restricted with the scope of output voltage.
Therefore, it is desirable to further realize wide input and output voltage range.
Utility model content
In view of this, the purpose of this utility model is to provide Switching Power Supply and its control circuit, wherein control circuit root
The reference cycle is adjusted according to time parameter.
According to first aspect of the present utility model, there is provided a kind of control circuit for Switching Power Supply, including：Adjust mould
Block, for the cycle of switching signal and reference cycle to be compared to produce the first control voltage；Current source module, for root
The first charging current is produced according to first control voltage；Pulse signal generation module, for first charging current to be turned
It is changed to switch conduction or turn-off time signal；Drive module, for producing institute according to the switch conduction or turn-off time signal
Switching signal is stated, with the conducting of controlling switch pipe and shut-off；And measure of time module, for being obtained according to the switching signal
Time parameter and according to the time parameter produce periodic adjustment signal, wherein, the adjustment module is adjusted according to the cycle
Reference cycle described in section Signal Regulation, so as to adjust the cycle of the switching signal.
Preferably, under the permanent conducting control model of the Switching Power Supply, the measure of time module includes the turn-off time
Measuring circuit, for measuring the turn-off time of the switching signal as the time parameter, and when the turn-off time is little
When first threshold, the periodic adjustment signal increases the reference cycle.
Preferably, under the permanent shut-off control model of the Switching Power Supply, the measure of time module includes ON time
Detection circuit, and when the ON time is less than first threshold, the periodic adjustment signal increases the reference cycle.
Preferably, the adjustment module includes：Timing module, for producing reference cycle letter according to the switching signal
Number, the reference cycle signal is the pulse signal of triggering synchronous with the switching signal；Edge comparison module, for will be described
Reference cycle signal and the switching signal are compared, and to produce the first enable signal and second signal is enabled；Compensating module,
For providing first control voltage, and the first control electricity according to first enables signal and second enables Signal Regulation
The magnitude of voltage of pressure.
Preferably, the timing module includes：First electric capacity, at the two ends of first electric capacity the second control electricity is produced
Pressure；First current source, is connected with first capacitances in series, for providing the first electric current to first electric capacity；First switch,
It is connected in parallel with first electric capacity, for controlling the charging and discharging process of first electric capacity；First comparator, for inciting somebody to action
Second control voltage compared with the first reference voltage, so as to produce the reference cycle signal, wherein, described first opens
Close the turn-on and turn-off under the control of the switching signal, the charging interval that the timing module passes through change first electric capacity
To adjust the reference cycle.
Preferably, the adjustment module also includes：First voltage source, for providing first reference voltage, described
In the case of adjustment module increases the reference cycle, the current value of first current source reduces or/and first reference
Voltage is raised, and so as to extend the charging interval of first electric capacity, in the adjustment module situation in the reference cycle is reduced
Under, the current value of first current source increases or/and first reference voltage reduction, so as to reduce first electric capacity
Charging interval.
According to second aspect of the present utility model, there is provided a kind of Switching Power Supply, including：Main circuit；And above-mentioned control
Circuit, wherein, the main circuit includes switching tube, and the control circuit controls the turn-on and turn-off of the switching tube.
Preferably, the main circuit is in booster type topology, buck topology, buck-boost type topological sum flyback topology
Any one.
According to the switching power source control circuit of this utility model embodiment, using the dynamic control compensating switch in reference cycle
The change of the event argument of signal, so as to realize wide input, output voltage range, and improves system stability.
Under the permanent conducting control model of Switching Power Supply, in corresponding preferred embodiment, if the turn-off time is less than the
One threshold value, then reference cycle prolongation, minimum turn-off time of the first threshold corresponding to system.According to the turn-off time of switching signal
The dynamic regulation reference cycle so that the turn-off time is consistently greater than the minimum turn-off time.Thus, the control method is by ginseng
Examine the cycle dynamic control come compensating switch signal turn-off time change, such that it is able to further improve maximum duty cycle
Dmax, realizes wide input and output voltage range.
Under the permanent conducting control model of Switching Power Supply, in corresponding preferred embodiment, if the turn-off time more than etc.
In first threshold, then reference cycle reduction.According to dynamic regulation reference cycle turn-off time of switching signal, in switching signal
Turn-off time, the control circuit further improved the frequency of switching signal more than on the premise of the minimum turn-off time, such that it is able to
Improve system effectiveness and avoid the generation of audio-frequency noise.
Under the permanent shut-off control model of Switching Power Supply, in corresponding preferred embodiment, if ON time is less than the
Two threshold values, then reference cycle prolongation, minimum ON time of the Second Threshold corresponding to system.According to the ON time of switching signal
The dynamic regulation reference cycle so that the ON time is consistently greater than minimum ON time.Thus, the control method is by ginseng
Examine the cycle dynamic control come compensating switch signal ON time change, such that it is able to further reduce minimum duty cycle
Dmin, realizes wide input and output voltage range.
Under the permanent shut-off control model of Switching Power Supply, in corresponding preferred embodiment, if ON time more than etc.
In Second Threshold, then reference cycle reduction.According to the ON time dynamic regulation reference cycle of switching signal, in switching signal
On the premise of ON time is more than minimum ON time, the control circuit further improves the frequency of switching signal, such that it is able to
Improve system effectiveness and avoid the generation of audio-frequency noise.
Description of the drawings
By referring to the drawings to the description of this utility model embodiment, of the present utility model above-mentioned and other mesh
, feature and advantage will be apparent from.
Fig. 1 illustrates the schematic block diagram of BUCK type Switching Power Supplies.
Fig. 2 illustrates the schematic block diagram of BOOST type Switching Power Supplies.
Fig. 3 illustrates the schematic block diagram of the existing control circuit adopted in Switching Power Supply shown in Fig. 1 and 2.
Fig. 4 to 5 is shown respectively the timing module, adjustment module and the drive module that adopt in control circuit shown in Fig. 2
Schematic block diagram.
Fig. 6 a illustrate the pulse signal adopted in the permanent control circuit turned under control model shown in Fig. 2 of Switching Power Supply
The schematic block diagram of generation module.
Fig. 6 b illustrate the pulse signal adopted in the permanent control circuit turned off under control model shown in Fig. 2 of Switching Power Supply
The schematic block diagram of generation module.
Fig. 7 illustrates the schematic block diagram of the switching power source control circuit according to this utility model first embodiment.
Fig. 8 illustrates a kind of schematic block diagram of the timing module adopted in control circuit shown in Fig. 7.
Fig. 9 illustrates the schematic block diagram of another kind of timing module adopted in control circuit shown in Fig. 7.
Figure 10 illustrates the flow process of the constant turn-on time control method of the Switching Power Supply according to this utility model second embodiment
Figure.
Figure 11 illustrates the flow process of the constant turn-on time control method of the Switching Power Supply according to this utility model 3rd embodiment
Figure.
Figure 12 illustrates the flow process of the constant turn-on time control method of the Switching Power Supply according to this utility model fourth embodiment
Figure.
Figure 13 illustrates the flow process of the permanent turn-off time control method of the Switching Power Supply according to the embodiment of this utility model the 5th
Figure.
Figure 14 illustrates the flow process of the permanent turn-off time control method of the Switching Power Supply according to this utility model sixth embodiment
Figure.
Figure 15 illustrates the flow process of the permanent turn-off time control method of the Switching Power Supply according to the embodiment of this utility model the 7th
Figure.
Specific embodiment
This utility model is more fully described hereinafter with reference to accompanying drawing.In various figures, identical element is using similar
Reference representing.For the sake of clarity, the various pieces in accompanying drawing are not necessarily to scale.Additionally, may in figure
Not shown some known parts.
Describe hereinafter many specific details of the present utility model, the structure of such as device, material, size, place
Science and engineering skill and technology, to be more clearly understood that this utility model.But just as the skilled person will understand,
This utility model can not be realized according to these specific details.
This utility model is more fully described hereinafter with reference to accompanying drawing.In various figures, identical element is using similar
Reference representing.For the sake of clarity, the various pieces in accompanying drawing are not necessarily to scale.Additionally, may in figure
Not shown some known parts.
Describe hereinafter many specific details of the present utility model, the structure of such as device, material, size, place
Science and engineering skill and technology, to be more clearly understood that this utility model.But just as the skilled person will understand,
This utility model can not be realized according to these specific details.
Fig. 1 illustrates the schematic block diagram of voltage-dropping type (BUCK) Switching Power Supply.As shown in figure 1, Switching Power Supply 100 has receiving
The input of DC input voitage Vin and the outfan for providing VD Vout.The main circuit of Switching Power Supply 100
Including electric capacity Cin and Cout, switching tube M1, diode D1 and inductance L1.The control circuit 110 of Switching Power Supply 100 is switching tube
M1 provides switching signal Vg.
In the main circuit of Switching Power Supply 100, electric capacity Cin is connected between input and ground, for direct current input electricity
Pressure Vin is filtered.Electric capacity Cout is connected between outfan and ground, for providing VD Vout.Switching tube M1
And diode D1 is connected in series between input and ground.Switching tube M1 has first end, the second end and control end.Switching tube M1
Control end receive switching signal Vg, and in the on-state electric current flow to the second end from first end.The anode of diode D1
Ground connection, negative electrode is connected to second end of switching tube M1.Inductance L1 is connected to the intermediate node of switching tube M1 and diode D1 and defeated
Go out between end.
Switching tube M1 is, for example, selected from mos field effect transistor (MOSFET) and bipolar transistor
It is a kind of.For example, switching tube M1 is N-type MOSFET, and first end, the second end and control end are respectively drain electrode, source electrode and grid.
The control circuit 110 of Switching Power Supply 100 connects respectively the input and outfan and switching tube for transporting to main circuit
The control end of M1.As mentioned below, control circuit 110 includes the circuit module such as comparator and pulse signal generation module.Control
The VD Vout that the DC input voitage Vin and outfan that circuit 110 is provided using input is provided, produces power supply
Voltage and/or reference voltage, to be supplied to internal circuit blocks to use.Additionally, DC input voitage Vin and VD
Vout further provides for feedback signal, and control circuit 110 produces switching signal according to feedback signal, so as to controlling switch pipe M1 exists
ON time and turn-off time in each switch periods, that is, adjust dutycycle so that VD constant.
During the conducting of switching tube M1, it is defeated that switching tube M1 is substantially equal to direct current with the voltage of the intermediate node of diode D1
Enter voltage Vin, diode D1 reversely ends.DC input voitage Vin charges via switching tube M1 to inductance L1, inductive current IL
Flow through inductance L1 and linearly increasing.Meanwhile, DC input voitage Vin charges to electric capacity Cout, produces at the two ends of electric capacity Cout
VD Vout.
During the shut-off of switching tube M1, due to the electric current retention performance of inductance L1, inductive current IL continues flow through inductance
L1, inductive current IL linearly reduces.The reversing at inductance L1 two ends so that diode D1 forward conductions.Electric capacity Cout discharges,
So as to maintain VD Vout.
In BUCK type Switching Power Supplies, VD Vout and DC input voitage Vin and switching signal Vg are accounted for
It is empty more related than D, that is, meet the relation of Vout=Vin*D.
Fig. 2 illustrates the schematic block diagram of booster type (BOOST) Switching Power Supply.As shown in Fig. 2 Switching Power Supply 200 has connecing
Receive the input and the outfan for providing VD Vout of DC input voitage Vin.The main electricity of Switching Power Supply 200
Road includes electric capacity Cin and Cout, switching tube M1, diode D1 and inductance L1.The control circuit 210 of Switching Power Supply 200 is switch
Pipe M1 provides switching signal Vg.
In the main circuit of Switching Power Supply 200, electric capacity Cin is connected between input and ground, for direct current input electricity
Pressure Vin is filtered.Electric capacity Cout is connected between outfan and ground, for providing VD Vout.Inductance L1 and
Switching tube M1 is connected in series between input and ground.Switching tube M1 has first end, the second end and control end.Switching tube M1's
Control end receives switching signal Vg, and in the on-state electric current flow to the second end from first end.The anode of diode D1 connects
The intermediate node of inductance L1 and switching tube M1 is connected on, the negative electrode of diode D1 is connected to outfan.
The control circuit 210 of Switching Power Supply 200 connects respectively the input and outfan and switching tube for transporting to main circuit
The control end of M1.As mentioned below, control circuit 210 includes the circuit module such as comparator and pulse signal generation module.Control
The VD Vout that the DC input voitage Vin and outfan that circuit 210 is provided using input is provided, produces power supply
Voltage and/or reference voltage, to be supplied to internal circuit blocks to use.Additionally, DC input voitage Vin and VD
Vout further provides for feedback signal, and control circuit 210 produces switching signal according to feedback signal, so as to controlling switch pipe M1 exists
ON time and turn-off time in each switch periods, that is, adjust dutycycle so that VD constant.
During the conducting of switching tube M1, the intermediate node of inductance L1 and switching tube M1 is grounded via switching tube M1, two poles
Pipe D1 reversely ends.DC input voitage Vin charges to inductance L1, and inductive current IL flows through inductance L1 and linearly increasing.Two poles
Pipe D1 prevents electric capacity Cout from discharging via switching tube M1, so as to maintain the VD Vout at electric capacity Cout two ends.
During the shut-off of switching tube M1, due to the electric current retention performance of inductance L1, inductive current IL continues flow through inductance
L1, inductive current IL linearly reduces.The reversing at inductance L1 two ends so that diode D1 forward conductions.Inductive current IL gives
Electric capacity Cout charges, and at the two ends of electric capacity Cout VD Vout is produced.Now, the direct current output at electric capacity Cout two ends
Voltage Vout is higher than DC input voitage Vin.
In BOOST type Switching Power Supplies, VD Vout and DC input voitage Vin and switching signal Vg are accounted for
It is empty more related than D, that is, meet the relation of Vout=Vin/D.
It is described mainly for circuit operation principle under the permanent conducting control model of Switching Power Supply below.
Fig. 3 illustrates the schematic block diagram of the existing control circuit adopted in Switching Power Supply shown in Fig. 1 and 2.
As shown in figure 3, control circuit 110 includes adjustment module 111, current source module 112, pulse signal generation module
113 and drive module 115.Adjustment module 111 produces control voltage Vc according to switching signal Vg.Current source module 112 is according to control
Voltage Vc processed produces charging current Ic.Pulse signal generation module 113 produces switch conduction times signal according to charging current Ic
TON.Drive module produces switching signal Vg according to switch conduction times signal TON.Under permanent shut-off control model, pulse signal
Generation module 113 produces switch OFF time signal TOFF according to charging current Ic.Drive module is believed according to switch OFF time
Number TOFF produces switching signal Vg.
Adjustment module 111 includes timing module 1111, edge comparison module 1112 and compensating module 1113.Timing mould
Block 1111 receives switching signal Vg, and produces reference cycle signal Tref according to switching signal Vg.Edge comparison module 1112
Input IN1 and IN2 receive reference cycle signal Tref and switching signal Vg respectively, the two is compared, with acquisition
Adjust to enable signal u_en and lower and enable signal d_en.Compensating module 1113 is used to produce control voltage Vc, and according to rise
Enable signal u_en and lower and enable the magnitude of voltage that signal d_en adjusts control voltage Vc.
In the course of work of control circuit 110, adjustment module 111 is performed in multiple continuous cycles of switching signal Vg
Hereinafter operate.
In moment t0, switching signal Vg is changed into high level from low level, so as to start the new cycle.Timing module 1111
Start timing from the rising edge of switching signal Vg, produce reference cycle signal Tref.
In moment t2, through a cycle T of switching signal Vg, the second input IN2 of edge comparison module 1112 connects
Receive the rising edge of next switching signal Vg.
The level and switching signal of the switch conduction times signal TON of the first input end IN1 of edge comparison module 1112
The actual cycle T-phase of Vg is closed.When actual cycle T of switching signal Vg is less than the reference cycle, the ginseng of the output of timing module 1111
It is low level that periodic signal Tref is examined in moment t2.When actual cycle T of switching signal Vg is more than the reference cycle, timing module
The reference cycle signal Tref of 1111 outputs is high level in moment t2.
Reference cycle signal Tref and the second input that edge comparison module 1112 detects first input end IN1
Switching signal Vg that IN2 is detected compares.In moment t1, if reference cycle signal Tref is high level, edge compares
The rise that first outfan UP of module 1112 is provided enables signal u_en effectively, and the downward that the second outfan DOWN is provided is enabled
Signal d_en is invalid., whereas if the reference cycle signal Tref that the first input end IN1 of edge comparison module 1112 is detected
For low level, then the rise enable signal u_en of the first outfan UP offers of edge comparison module 1112 is invalid, the second output
It is effective that the downward that end DOWN is provided enables signal d_en.
Compensating module 1113 enables the electricity that signal d_en adjusts control voltage Vc according to enable signal u_en is raised with lowering
Pressure value.If raise enabling signal u_en effectively, the control voltage Vc liter that compensating module 1113 exports current source module 112
High predetermined value.If lower enabling signal d_en effectively, the control voltage that compensating module 1113 exports current source module 112
Vc reduces predetermined value.
Current source module 112 receives control voltage Vc, and according to the current value of Voltage Cortrol charging current Ic.If control
Voltage Vc processed is raised, and charging current Ic raises predetermined value.If control voltage Vc is reduced, charging current Ic reduces predetermined value.
In one embodiment, current source module 112 includes Voltage to current transducer module, will control voltage Vc by certain
Ratio is converted to the output of charging current Ic.In alternate embodiments, current source module 112 includes controlled current source, will control
Voltage Vc processed changes the size of charging current Ic as control signal by control electric current source.
Under permanent conducting control model, pulse signal generation module 113 electric capacity is charged using charging current Ic and
Electric discharge, produces switch conduction times signal TON.Drive module 115 produces switching signal according to switch conduction times signal TON
Vg, the cycle of switching signal Vg is related to the current value of charging current Ic, thus can pass through the electric current of control charging current Ic
Value, realizes the adjustment to switching signal Vg cycle T.Under permanent shut-off control model, pulse signal generation module 113 is using charging
Electric current Ic is charged and discharged to electric capacity, produces switch OFF time signal TOFF.When drive module 115 is according to switch OFF
Between signal TOFF produce switching signal Vg,
In multiple continuous cycles of switching signal Vg, control circuit 110 repeats said process so that switching signal Vg
In the Approach by inchmeal reference cycle in cycle, finally realize stable switch periods T.
Fig. 4 illustrates the schematic block diagram of the timing module adopted in control circuit shown in Fig. 2.As shown in figure 4, timing mould
Block 1111 includes comparator U11, voltage source VS11, current source CS11, electric capacity C11 and switch K11.
Current source CS11 and electric capacity C11 are connected in series between feeder ear and ground, and the intermediate node of the two produces control electricity
Pressure Vc1.Switch K11 and electric capacity C11 is connected in parallel, and the turn-on and turn-off under the control of switching signal Vg.
The in-phase input end of comparator U11 is connected to the intermediate node of current source CS11 and electric capacity C11 to receive control electricity
Pressure Vc1, inverting input is connected to voltage source VS11 to receive reference voltage Vref 1.The outfan of comparator U11 is connected to side
Along comparison module 1112, so as to latter provides reference cycle signal Tref.
In the course of work of control circuit 110, timing module 1111 is held in multiple continuous cycles of switching signal Vg
The following operation of row.
In moment t0, switching signal Vg is changed into high level from low level, so as to start the new cycle.Switch K11 is being opened
Turn under the control of OFF signal Vg, electric capacity C11 starts electric discharge.The control that the intermediate node of current source CS11 and electric capacity C11 is produced
Voltage Vc1 is no-voltage.The ON time of switch K11, is shorter than MOS ON times, such as 30ns.Now, voltage is answered on electric capacity C11
Position is to 0.Switch K11 disconnects, and current source CS11 is charged to electric capacity C11.The intermediate node of current source CS11 and electric capacity C11 is produced
Raw control voltage Vc1 gradually rises.
In moment t1, switching signal Vg is changed into low level from high level, and in moment t2, switching signal Vg turns from low level
It is changed into high level.
In the time period of above-mentioned moment t1 to t2, switching signal Vg is the low level stage, and the switching tube M1 of main circuit is being opened
Turn off under the control of OFF signal Vg.The low level stage corresponds to the off-phases of switching tube M1, so as to the corresponding time period pair
Should be in the turn-off time Tf of switching tube M1.In moment t2, switching signal Vg starts next cycle, and switch K11 is in switching signal
Turn on again under the control of Vg, electric capacity C11 restarts electric discharge.
In multiple continuous cycles of switching signal Vg, timing module 1111 repeats said process.
Voltage source VS11 in timing module 1111 provides reference voltage Vref 1, for characterizing the reference of switching signal Vg
Cycle.Comparator U11 is compared control voltage Vc1 and reference voltage Vref 1, so as to provide reference cycle letter in outfan
Number Tref.
If the ceiling voltage of control voltage Vc1 is increased to reference voltage Vref 1, show the cycle T of switching signal Vg
It is identical with the reference cycle that the inside of timing module 1111 is arranged.Between when off at the end of Tf (i.e. above-mentioned moment t2), reference
Periodic signal Tref substantially overturns simultaneously with switching signal Vg, i.e., be changed into high level from low level.
If the ceiling voltage of control voltage Vc1 fails to reach reference voltage Vref 1, show the cycle of switching signal Vg
T is less than the reference cycle that the inside of timing module 1111 is arranged.Between when off at the end of Tf (i.e. above-mentioned moment t2), switch letter
Number Vg upset and reference cycle signal Tref does not overturn, i.e., switching signal Vg is changed into high level, reference cycle letter from low level
Number Tref is still maintained low level.
If control voltage Vc1 when off between Tf terminate to have risen to reference voltage Vref 1 in the past, show switch
The cycle T of signal Vg is more than the reference cycle that the inside of timing module 1111 is arranged.Between when off at the end of Tf (when i.e. above-mentioned
Carve t2), the upset of switching signal Vg, i.e., switching signal Vg is changed into high level from low level.Before Tf terminates between when off, ginseng
Examine periodic signal Tref and be changed into high level from low level, and when off between at the end of Tf (i.e. above-mentioned moment t2)
Still it is maintained high level.
Varying level state representation switching signal Vg of the reference cycle signal Tref that timing module 1111 is produced and reference
The comparative result in cycle.As described above, reference cycle signal Tref upsets synchronous with switching signal Vg represent switching signal Vg
Cycle be equal to the reference cycle, reference cycle signal Tref relative to switching signal Vg overturn in advance represent switching signal Vg week
Phase is more than the reference cycle, and reference cycle signal Tref does not overturn and represents that the cycle of switching signal Vg is less than the reference cycle.
Fig. 5 illustrates the schematic block diagram of the compensating module adopted in control circuit shown in Fig. 2.Compensating module 1113 includes
Current source CS21, current source CS22, switch K21, switch K22 and electric capacity C21.Current source CS21, switch K21, switch K22
And current source CS22 is sequentially connected in series between feeder ear and ground.Switch K21 leads in the case where the control for enabling signal u_en is raised
Logical and shut-off, switchs K22 turn-on and turn-off in the case where the control for enabling signal d_en is lowered.Electric capacity C21 is connected to switch K21 and opens
Close between the intermediate node and ground of K22.Control voltage Vc is produced at the two ends of electric capacity C21.
In the course of work of control circuit 110, compensating module 1113 is held in multiple continuous cycles of switching signal Vg
The following operation of row.
If the rise that compensating module 1113 is received enables signal u_en and downward enable signal d_en is invalid, open
Close K21 and switch K22 to be turned off, the top crown voltage of electric capacity C21 keeps constant, i.e., control voltage Vc is constant.
If the rise that compensating module 1113 is received enables signal u_en effectively and downward enable signal d_en is invalid,
Switch K21 conductings, switch K22 shut-offs.Now, current source CS21 is charged to electric capacity C21, raises control voltage Vc.
If it is invalid and lower and enable signal d_en effectively that rise that compensating module 1113 is received enables signal u_en,
Switch K21 shut-offs, switch K22 conductings.Now, the two ends of electric capacity C21 are connected to each other via switch K22 and current source CS22.Electricity
Stream source CS22 provides discharge current for electric capacity C21, reduces control voltage Vc.
Thus, compensating module 1113 produces control voltage Vc by the charging and discharging to electric capacity C21, and according to rise
Enable signal u_en and lower and enable the magnitude of voltage that signal d_en adjusts control voltage Vc.
Fig. 6 a and 6b is shown respectively to be controlled under the permanent conducting control model and permanent shut-off control model of Switching Power Supply shown in Fig. 2
The schematic block diagram of the pulse signal generation module adopted in circuit processed.
As shown in Fig. 6 a and Fig. 6 b, pulse signal generation module 113 includes comparator U10, voltage source VS10, current source
CS10, electric capacity C10, switch K10.
The first end of electric capacity C10 receives charging current Ic, the second end ground connection.Control voltage is produced at the two ends of electric capacity C10
Vc2.Switch K10 and electric capacity C10 is connected in parallel, and the turn-on and turn-off under the control of switching signal Vg.
In permanent conducting control model, the outfan output switch ON time signal TON of comparator U10；In permanent shut-off
In control model, the outfan output switch turn-off time signal TOFF of comparator U10；The switch conduction times signal TON
Or switch OFF time signal TOFF is input into drive module 115, the output switching signal Vg of drive module 115.
The inverting input of comparator U10 is connected to the first end of electric capacity C10 to receive control voltage Vc2, homophase input
End is connected to voltage source VS10 to receive reference voltage Vref 2.
It is described as a example by the control circuit by Switching Power Supply under permanent conducting control model below.
In the course of work of control circuit 110, pulse signal generation module 113 is with drive module 115 in switching signal
Following operation is performed in multiple continuous cycles of Vg.
In moment t1, switching signal Vg that drive module 115 is produced is high level.
Switch K10 is turned off under the control of switching signal Vg, and electric capacity C10 is charged using charging current Ic.Current source
Control voltage Vc2 that the intermediate node of CS10 and electric capacity C10 is produced gradually rises.
Comparator U10 is compared control voltage Vc2 and reference voltage Vref 2, and produces switch conduction times letter
Number TON.In the case of control voltage Vc2 is less than reference voltage Vref 2, switch conduction times signal TON maintains high level.
In moment t2, control voltage Vc2 is increased to reference voltage Vref 2, the switch conduction times letter that comparator U10 is produced
Number TON is changed into low level from high level.
The time period of moment t1 to t2 is the ON time Tn of switching signal Vg.The drive module 115 detects switch
The trailing edge of ON time signal TON so that switching signal Vg is changed into low level from high level.
In multiple continuous cycles of switching signal Vg, pulse signal generation module 113 repeats above-mentioned with drive module 115
Process.In the turn-off time Tf of switching signal Vg, electric capacity C10 is discharged to no-voltage.In the ON time Tn of switching signal Vg
In, current source CS10 is charged to electric capacity C10.
Thus, switching signal Vg that drive module 115 is produced is rendered as pwm signal.The high level stage of switching signal Vg
Corresponding to the ON time Tn of the switching tube M1 of main circuit, turn-off time of the low level stage corresponding to the switching tube M1 of main circuit
Tf.The cycle T of switching signal Vg is equal to ON time Tn and turn-off time Tf sum.
In the ideal case, the cycle T constant of switching signal Vg.However, due in pulse signal generation module 113
The factor such as comparator U10 time delays impact, therefore the cycle potentially unstable of switching signal Vg.Existing control as shown in Figure 3
Circuit processed 110 adopts adjustment module 111, and according to switching signal Vg reference cycle signal Tref, the reference cycle signal are produced
Tref is the pulse signal with the reference cycle of triggering synchronous with the switching signal, for compared with switching signal Vg with
The difference in the two cycle is indicated, further control voltage Vc is produced according to reference cycle signal Tref.Control voltage Vc is used for
Charging current Ic that correcting current source module 112 is provided, so that the cycle T constant of switching signal Vg.
Above-mentioned existing control circuit can be realized determining frequency on-off control, so as to solve to cause because of the original such as time delay, error
Working cycle unstable problem.However, under the permanent conducting control model of Switching Power Supply, the modules of control circuit are held
The row time determines the minimum turn-off time Tf_min of control circuit with detection time.In the feelings of the constant period of switching signal Vg
Under shape, the maximum duty cycle Dmax=1- minimum turn-off time Tf_min/T of switching signal Vg, so as to maximum duty cycle is subject to most
The restriction of little turn-off time Tf_min.Under the permanent shut-off control model of Switching Power Supply, the execution of the modules of control circuit
Time determines the minimum ON time Tn_min of control circuit with detection time.In the situation of the constant period of switching signal Vg
Under, the minimum duty cycle Dmin=minimum ON time Tn_min/T of switching signal Vg leads so as to minimum duty cycle receives minimum
The restriction of logical time Tn_min.
Further, because the input voltage vin and output voltage Vout of dutycycle D and Switching Power Supply have certain pass
System, therefore maximum duty cycle Dmax limits the input and output voltage scope of Switching Power Supply with minimum duty cycle Dmin.For example exist
In BUCK circuits, Vout=Vin*D, when the output voltage Vout of system requirements is more than maximum duty cycle Dmax and maximum input electricity
During the product of pressure Vin_max, because Dmax is fixed, therefore the output voltage required by system will be unable to by above-mentioned existing control
Circuit realiration.Again for example in BOOST circuits, Vout=Vin/D, when the output voltage Vout of system requirements is less than minimum input
During the ratio of voltage Vin_min and maximum duty cycle Dmax, because Dmax is fixed, will be unable to by above-mentioned existing control circuit reality
Now obtain the output voltage Vout required by system.
Fig. 7 illustrates the schematic block diagram of the switching power source control circuit according to this utility model first embodiment.Such as Fig. 7 institutes
Show, control circuit 210 includes adjustment module 211, current source module 212, pulse signal generation module 213, measure of time module
214 and drive module 215.Adjustment module 211 produces control voltage Vc according to switching signal Vg.Current source module 212 is according to control
Voltage Vc processed produces charging current Ic.In permanent conducting control model, pulse signal generation module 213 is produced according to charging current Ic
Raw switch conduction times signal TON.Drive module 215 produces switching signal Vg according to switch conduction times signal TON.
Current source module 212, pulse signal generation module in the switching power source control circuit 210 of the embodiment
213 and drive module 215 and Fig. 3 shown in existing switching power source control circuit 110 in corresponding module circuit structure and work(
Can be identical, will not be described in detail herein.The difference of the two is below only described.
Adjustment module 211 includes timing module 2111, edge comparison module 2112 and compensating module 2113.Timing mould
Block 2111 receives switching signal Vg, and produces reference cycle signal Tref according to switching signal Vg.Edge comparison module 2112
Input IN1 and IN2 receive reference cycle signal Tref and switching signal Vg respectively, the two is compared, with acquisition
Adjust to enable signal u_en and lower and enable signal d_en.Compensating module 2113 is used to produce control voltage Vc, and according to rise
Enable signal u_en and lower and enable the magnitude of voltage that signal d_en adjusts control voltage Vc.
Under the constant turn-on time control model of on-off circuit, measure of time module 214 is used for detection switch signal Vg's
Turn-off time Tf, and periodic adjustment signal l_en is produced according to testing result, for controlling to adjust the reference week of module 211
Phase.
For example, measure of time module 214 includes pulse width measurement circuit and comparator.The pulse width measurement circuit is used
In the low duration of measurement switching signal Vg, so as to obtain the turn-off time Tf of switching signal Vg.The comparator will be closed
Disconnected time Tf is compared with first threshold Tth1, and produces periodic adjustment signal l_en.For example, first threshold Tth1 is more than
Equal to minimum turn-off time Tf_min.
When the turn-off time Tf of switching signal Vg is less than first threshold Tth1, the cycle that measure of time module 214 is produced
Regulate signal l_en causes the reference cycle of timing module 2111 to increase.Thus, control circuit 210 utilizes the dynamic in reference cycle
The change of the turn-off time of control and compensation switching signal, such that it is able to further improve maximum duty cycle Dmax, realizes wide input
And output voltage range.
Further, when the turn-off time Tf of switching signal Vg is more than or equal to first threshold Tth1, the control circuit can
Further to improve the frequency of switching signal Vg.The periodic adjustment signal l_en that measure of time module 214 is produced causes timing mould
The reference cycle of block 2111 reduces.Thus, it is more than or equal to minimum turn-off time Tf_min in the turn-off time Tf of switching signal Vg
On the premise of, control circuit 210 further improves the frequency of switching signal, such that it is able to improving system effectiveness and avoiding audio frequency
The generation of noise.
Under the permanent turn-off time control model of on-off circuit, measure of time module 214 is used for detection switch signal Vg's
ON time Tn, and periodic adjustment signal l_en is produced according to testing result, for controlling to adjust the reference week of module 211
Phase.
For example, measure of time module 214 includes pulse width measurement circuit and comparator.The pulse width measurement circuit is used
In the high level lasting time of measurement switching signal Vg, so as to obtain the ON time Tn of switching signal Vg.The comparator will lead
Logical time Tn and Second Threshold Tth2 is compared, and produces periodic adjustment signal l_en.For example, Second Threshold Tth2 is more than
Equal to minimum ON time Tn_min.
When the ON time Tn of switching signal Vg is less than Second Threshold Tth2, the cycle that measure of time module 214 is produced
Regulate signal l_en causes the reference cycle of timing module 2111 to increase.Thus, control circuit 210 utilizes the dynamic in reference cycle
The change of the ON time of control and compensation switching signal, such that it is able to further reduce minimum duty cycle Dmin, realizes wide input
And output voltage range.
Further, when the ON time Tn of switching signal Vg is more than or equal to Second Threshold Tth2, the control circuit can
Further to improve the frequency of switching signal Vg.The periodic adjustment signal l_en that measure of time module 214 is produced causes timing mould
The reference cycle of block 2111 reduces.Thus, it is more than or equal to minimum ON time Tn_min in the ON time Tn of switching signal Vg
On the premise of, control circuit 210 further improves the frequency of switching signal, such that it is able to improving system effectiveness and avoiding audio frequency
The generation of noise.
Fig. 8 illustrates a kind of schematic block diagram of the timing module adopted in control circuit shown in Fig. 7.As shown in figure 8, timing
Module 2111 includes comparator U11, voltage source VS11, current source CS11, electric capacity C11 and switch K11.
Current source CS11 and electric capacity C11 are connected in series between feeder ear and ground, and the intermediate node of the two produces control electricity
Pressure Vc1.Switch K11 and electric capacity C11 is connected in parallel, and the turn-on and turn-off under the control of switching signal Vg.
The in-phase input end of comparator U11 is connected to the intermediate node of current source CS11 and electric capacity C11 to receive control electricity
Pressure Vc1, inverting input is connected to voltage source VS11 to receive reference voltage Vref 1.The outfan of comparator U11 is connected to side
Along comparison module 2112, so as to latter provides reference cycle signal Tref.
Timing module 2111 in the switching power source control circuit 210 of the embodiment and the existing switch shown in Fig. 4
It is to be believed according to periodic adjustment that the difference of the circuit structure of the corresponding module in power control circuit 110 is current source CS11
Number l_en changes the controlled current source of current value.
Further, current source CS11 changes current value according to periodic adjustment signal l_en.
When periodic adjustment signal l_en is effective, the current value of current source CS11 reduces.The electric capacity C11 charging intervals are elongated,
So as to increase the reference cycle.Correspondingly, adjustment module 111 raises control voltage Vc, makes the charging electricity that current source module 112 is produced
Stream Ic reduces, so as to reach the purpose of increase switch periods T.
When periodic adjustment signal l_en is invalid, the current value of current source CS11 remains unchanged, and frequency on-off control is determined in realization,
Or current value increases.In the case of current value increases, the electric capacity C11 charging intervals shorten, so as to reduce the reference cycle.Accordingly
Ground, adjustment module 111 lowers control voltage Vc, the charging current Ic increase that current source module 112 is produced is made, so as to reach reduction
The purpose of increase switch periods T.
Fig. 9 illustrates the schematic block diagram of another kind of timing module adopted in control circuit shown in Fig. 7.As shown in figure 9, meter
When module 3111 include comparator U11, voltage source VS11, current source CS11, electric capacity C11 and switch K11.
Current source CS11 and electric capacity C11 are connected in series between feeder ear and ground, and the intermediate node of the two produces control electricity
Pressure Vc1.Switch K11 and electric capacity C11 is connected in parallel, and the turn-on and turn-off under the control of switching signal Vg.
The in-phase input end of comparator U11 is connected to the intermediate node of current source CS11 and electric capacity C11 to receive control electricity
Pressure Vc1, inverting input is connected to voltage source VS11 to receive reference voltage Vref 1.The outfan of comparator U11 is connected to side
Along comparison module 2112, so as to latter provides reference cycle signal Tref.
Timing module 3111 in the switching power source control circuit 210 of the embodiment and the existing switch shown in Fig. 4
It is to be believed according to periodic adjustment that the difference of the circuit structure of the corresponding module in power control circuit 110 is voltage source VS11
Number l_en changes the controlled voltage source of magnitude of voltage.
Further, current source CS11 changes current value according to periodic adjustment signal l_en.
When periodic adjustment signal l_en is effective, the current value of current source CS11 reduces.The electric capacity C11 charging intervals are elongated,
So as to increase the reference cycle.Correspondingly, adjustment module 111 raises control voltage Vc, makes the charging electricity that current source module 112 is produced
Stream Ic reduces, so as to reach the purpose of increase switch periods T.
When periodic adjustment signal l_en is invalid, the current value of current source CS11 remains unchanged, and frequency on-off control is determined in realization,
Or current value increases.In the case of current value increases, the electric capacity C11 charging intervals shorten, so as to reduce the reference cycle.Accordingly
Ground, adjustment module 111 lowers control voltage Vc, the charging current Ic increase that current source module 112 is produced is made, so as to reach reduction
The purpose of increase switch periods T.
Further, voltage source VS11 changes magnitude of voltage according to periodic adjustment signal l_en.
When periodic adjustment signal l_en is effective, the magnitude of voltage increase of voltage source VS11.The electric capacity C11 charging intervals are elongated,
So as to increase the reference cycle.Correspondingly, adjustment module 111 raises control voltage Vc, makes the charging electricity that current source module 112 is produced
Stream Ic reduces, so as to reach the purpose of increase switch periods T.
When periodic adjustment signal l_en is invalid, the magnitude of voltage of voltage source VS11 remains unchanged, and frequency on-off control is determined in realization,
Or magnitude of voltage reduces.In the case of magnitude of voltage reduces, the electric capacity C11 charging intervals shorten, so as to reduce the reference cycle.Accordingly
Ground, adjustment module 111 lowers control voltage Vc, the charging current Ic increase that current source module 112 is produced is made, so as to reach reduction
The purpose of increase switch periods T.
Figure 10 illustrates the flow process of the constant turn-on time control method of the Switching Power Supply according to this utility model second embodiment
Figure.In this embodiment, after Switching Power Supply works on power, using the timing mould shown in the control circuit and Fig. 8 shown in Fig. 7
Block realizes the control method.However, this utility model not limited to this.
In step S101, the turn-off time Tf of detection switch signal.
In step s 102, judge the turn-off time Tf of switching signal whether less than first threshold Tth1.For example, the first threshold
Minimum turn-off time Tf_min of value Tth1 corresponding to system.If turn-off time Tf is less than first threshold Tth1, step is performed
Rapid S105, if turn-off time Tf is more than or equal to first threshold Tth1, execution step S104.
In step S104, the current value of current source CS11 in timing module 2111 is set to into predetermined value.Timing module
The charging interval constant of the electric capacity C11 in 2111 so that the reference cycle constant of timing module 2111.The control electricity
Road carries out determining frequency on-off control.
In step S105, whether the current value for judging current source has reached minima.If it is, abandoning timing mould
The regulation of current source CS11 in block 2111, returns execution step S101.If it is not, then execution step S106.The minimum of current source
Current value determines the reference cycle maximum of timing module 2111.
In step s 106, the current value of current source CS11 in timing module 2111 is reduced, so as to extend timing module
The charging interval of the electric capacity C11 in 2111 so that the reference cycle of timing module 2111 extends.The control circuit carries out determining frequency opening
Close control.Then, execution step S101 is returned.
Figure 11 illustrates the flow process of the constant turn-on time control method of the Switching Power Supply according to this utility model 3rd embodiment
Figure.In this embodiment, after Switching Power Supply works on power, using the timing mould shown in the control circuit and Fig. 8 shown in Fig. 7
Block realizes the control method.However, this utility model not limited to this.
Controlled shown in S201, S202, S205 and S206 and Figure 10 according to the step of the Switching Power Supply control method of the embodiment
The step of method processed, S101, S102, S105 were identical with S106 difference.The difference of the two is below only described.
In step S202, judge the turn-off time Tf of switching signal whether less than first threshold Tth1.For example, the first threshold
Minimum turn-off time Tf_min of value Tth1 corresponding to system.If turn-off time Tf is less than first threshold Tth1, step is performed
Rapid S205, if turn-off time Tf is more than or equal to first threshold Tth1, execution step S207.
In step S207, whether the current value for judging current source CS11 in timing module 2111 has been maxed out value.
If it is, execution step S201 is returned, if it is not, then execution step S208.The maximum current value of current source determines timing mould
The reference cycle minima of block 2111.
In step S208, by the current value increase of current source CS11 in timing module 2111.In timing module 2111
The charging interval of electric capacity C11 reduces so that the reference cycle of timing module 2111 reduces.Then, execution step S201 is returned.
Figure 12 illustrates the flow process of the constant turn-on time control method of the Switching Power Supply according to this utility model fourth embodiment
Figure.In this embodiment, after Switching Power Supply works on power, using the timing mould shown in the control circuit and Fig. 9 shown in Fig. 7
Block realizes the control method.However, this utility model not limited to this.
In step S301, the turn-off time Tf of detection switch signal.
In step s 302, judge the turn-off time Tf of switching signal whether less than first threshold Tth1.For example, the first threshold
Minimum turn-off time Tf_min of value Tth1 corresponding to system.If turn-off time Tf is less than first threshold Tth1, step is performed
Rapid S305, if turn-off time Tf is more than or equal to first threshold Tth1, execution step S307.
In step S305, whether the magnitude of voltage for judging current source has been maxed out value.If it is, abandoning timing mould
The regulation of voltage source VS11 in block 2111, returns execution step S301.If it is not, then execution step S306.The maximum of current source
Magnitude of voltage determines the reference cycle maximum of timing module 2111.
In step S306, by the magnitude of voltage increase of voltage source VS11 in timing module 2111, so as to extend timing module
The charging interval of the electric capacity C11 in 2111 so that the reference cycle of timing module 2111 extends.The control circuit carries out determining frequency opening
Close control.Then, execution step S301 is returned.
In step S307, whether the magnitude of voltage for judging voltage source VS11 in timing module 2111 has reached minima.
If it is, execution step S301 is returned, if it is not, then execution step S308.The minimum amount of voltage that of current source determines timing mould
The reference cycle minima of block 2111.
In step S308, the magnitude of voltage of voltage source VS11 in timing module 2111 is reduced.In timing module 2111
The charging interval of electric capacity C11 reduces so that the reference cycle of timing module 2111 reduces.Then, execution step S301 is returned.
Figure 13 illustrates the flow process of the permanent turn-off time control method of the Switching Power Supply according to the embodiment of this utility model the 5th
Figure.In this embodiment, after Switching Power Supply works on power, using the timing mould shown in the control circuit and Fig. 8 shown in Fig. 7
Block realizes the control method.However, this utility model not limited to this.
In step S401, the ON time Tn of detection switch signal.
In step S402, judge the ON time Tn of switching signal whether less than Second Threshold Tth2.For example, the second threshold
Minimum ON time Tn_min of value Tth2 corresponding to system.If ON time Tn is less than Second Threshold Tth2, step is performed
Rapid S405, if ON time Tn is more than or equal to Second Threshold Tth2, execution step S404.
It is identical to step S106 with step S104 to step S406 in step S404.
Figure 14 illustrates the flow process of the permanent turn-off time control method of the Switching Power Supply according to this utility model sixth embodiment
Figure.In this embodiment, after Switching Power Supply works on power, using the timing mould shown in the control circuit and Fig. 8 shown in Fig. 7
Block realizes the control method.However, this utility model not limited to this.
Controlled shown in S501, S502, S505 and S506 and Figure 13 according to the step of the Switching Power Supply control method of the embodiment
The step of method processed, S401, S402, S405 were identical with S406 difference.The difference of the two is below only described.
In step S502, judge the ON time Tn of switching signal whether less than Second Threshold Tth2.For example, the second threshold
Minimum ON time Tn_min of value Tth2 corresponding to system.If ON time Tn is less than Second Threshold Tth2, step is performed
Rapid S505, if ON time Tn is more than or equal to Second Threshold Tth2, execution step S507.
In step s 507, whether the current value for judging current source CS11 in timing module 2111 has been maxed out value.
If it is, execution step S501 is returned, if it is not, then execution step S508.The maximum current value of current source determines timing mould
The reference cycle minima of block 2111.
In step S508, by the current value increase of current source CS11 in timing module 2111.In timing module 2111
The charging interval of electric capacity C11 reduces so that the reference cycle of timing module 2111 reduces.Then, execution step S501 is returned.
Figure 15 illustrates the flow process of the permanent turn-off time control method of the Switching Power Supply according to the embodiment of this utility model the 7th
Figure.In this embodiment, after Switching Power Supply works on power, using the timing mould shown in the control circuit and Fig. 9 shown in Fig. 7
Block realizes the control method.However, this utility model not limited to this.
In step s 601, the ON time Tn of detection switch signal.
In step S602, judge the turn-off time Tn of switching signal whether less than Second Threshold Tth2.For example, the second threshold
Minimum ON time Tn_min of value Tth2 corresponding to system.If ON time Tn is less than Second Threshold Tth2, step is performed
Rapid S605, if ON time Tn is more than or equal to Second Threshold Tth2, execution step S607.
In step s 605, whether the magnitude of voltage for judging current source has been maxed out value.If it is, abandoning timing mould
The regulation of voltage source VS11 in block 2111, returns execution step S601.If it is not, then execution step S606.The maximum of current source
Magnitude of voltage determines the reference cycle maximum of timing module 2111.
In step S606, by the magnitude of voltage increase of voltage source VS11 in timing module 2111, so as to extend timing module
The charging interval of the electric capacity C11 in 2111 so that the reference cycle of timing module 2111 extends.The control circuit carries out determining frequency opening
Close control.Then, execution step S601 is returned.
In step S607, whether the magnitude of voltage for judging voltage source VS11 in timing module 2111 has reached minima.
If it is, execution step S601 is returned, if it is not, then execution step S608.The minimum amount of voltage that of current source determines timing mould
The reference cycle minima of block 2111.
In step S608, the magnitude of voltage of voltage source VS11 in timing module 2111 is reduced.In timing module 2111
The charging interval of electric capacity C11 reduces so that the reference cycle of timing module 2111 reduces.Then, execution step S601 is returned.
Turn-off time or ON time dynamic regulation timing mould of the control method of above-described embodiment according to switching signal
The reference cycle of block so that the turn-off time is consistently greater than minimum turn-off under the constant turn-on time control model of Switching Power Supply
Time Tf_min, the ON time is consistently greater than minimum ON time under the permanent turn-off time control model of Switching Power Supply
Tn_min.Thus, the control method utilizes the change of the time parameter of the dynamic control compensating switch signal in reference cycle, so as to
Maximum duty cycle Dmax can further be improved or further reduce minimum duty cycle Dmin, realize wide input and output voltage model
Enclose.Preferably, the control circuit further improves the frequency of switching signal, such that it is able to improving system effectiveness and avoiding audio frequency
The generation of noise.
It should be noted that herein, such as first and second or the like relational terms are used merely to a reality
Body or operation make a distinction with another entity or operation, and not necessarily require or imply these entities or deposit between operating
In any this actual relation or order.And, term " including ", "comprising" or its any other variant are intended to
Nonexcludability is included, so that a series of process, method, article or equipment including key elements not only will including those
Element, but also including other key elements being not expressly set out, or also include for this process, method, article or equipment
Intrinsic key element.In the absence of more restrictions, the key element for being limited by sentence "including a ...", it is not excluded that
Also there is other identical element in process, method, article or equipment including the key element.
According to embodiment of the present utility model as described above, these embodiments do not have all of details of detailed descriptionthe,
Also it is only described specific embodiment not limit the utility model.Obviously, as described above, many modifications and change can be made
Change.These embodiments are chosen and specifically described to this specification, is to preferably explain that principle of the present utility model and reality should
With so that skilled artisan can repairing using this utility model and on the basis of this utility model well
Change and use.This utility model is only limited by claims and its four corner and equivalent.
Claims (8)
1. a kind of control circuit for Switching Power Supply, including：
Adjustment module, for the cycle of switching signal and reference cycle to be compared to produce the first control voltage；
Current source module, for producing the first charging current according to first control voltage；
Pulse signal generation module, for first charging current to be converted to into switch conduction or turn-off time signal；
Drive module, for producing the switching signal according to the switch conduction or turn-off time signal, with controlling switch pipe
Conducting with shut-off；And
Measure of time module, for obtaining time parameter according to the switching signal and producing the cycle according to the time parameter
Regulate signal,
Wherein, adjustment module reference cycle according to the periodic adjustment Signal Regulation, so as to adjust the switch letter
Number cycle.
2. control circuit according to claim 1, wherein, the measure of time module includes turn-off time measuring circuit,
For measuring the turn-off time of the switching signal as the time parameter, and when the turn-off time is less than first threshold
When, the periodic adjustment signal increases the reference cycle.
3. control circuit according to claim 1, wherein, the measure of time module includes that ON time detects circuit,
And when the ON time is less than Second Threshold, the periodic adjustment signal increases the reference cycle.
4. control circuit according to claim 1, wherein, the adjustment module includes：
Timing module, for producing reference cycle signal according to the switching signal, the reference cycle signal is opened with described
The pulse signal that OFF signal is synchronously triggered；
Edge comparison module, for the reference cycle signal and the switching signal to be compared, to produce the first enable
Signal and second enables signal；
Compensating module, for providing first control voltage, and enables signal and the second enable Signal Regulation according to first
The magnitude of voltage of first control voltage.
5. control circuit according to claim 4, wherein, the timing module includes：
First electric capacity, at the two ends of first electric capacity the second control voltage is produced；
First current source, is connected with first capacitances in series, for providing the first electric current to first electric capacity；
First switch, is connected in parallel with first electric capacity, for controlling the charging and discharging process of first electric capacity；
First comparator, it is described with reference to week so as to produce for second control voltage to be compared with the first reference voltage
Phase signal,
Wherein, first switch turn-on and turn-off under the control of the switching signal, the timing module is by changing institute
State charging interval of the first electric capacity to adjust the reference cycle.
6. control circuit according to claim 5, wherein, the adjustment module also includes：
First voltage source, for providing first reference voltage, in the adjustment module situation in the reference cycle is increased
Under, the current value of first current source reduces or/and first reference voltage rising, so as to extend first electric capacity
Charging interval, in the case of the adjustment module reduces the reference cycle, the current value of first current source increase or/
Reduce with first reference voltage, so as to reduce the charging interval of first electric capacity.
7. a kind of Switching Power Supply, including：
Main circuit；And
Control circuit according to any one of claim 1-6,
Wherein, the main circuit includes switching tube, and the control circuit controls the turn-on and turn-off of the switching tube.
8. Switching Power Supply according to claim 7, wherein, the main circuit is booster type topology, buck topology, lifting
Any one in die mould topological sum flyback topology.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201621134639.XU CN206180848U (en) | 2016-10-19 | 2016-10-19 | Switching power supply and control circuit thereof |
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|---|---|---|---|
| CN201621134639.XU CN206180848U (en) | 2016-10-19 | 2016-10-19 | Switching power supply and control circuit thereof |
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| CN106385176A (en) * | 2016-10-19 | 2017-02-08 | 杰华特微电子（杭州）有限公司 | Switching power supply, control circuit thereof, and control method thereof |
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| CN109194118A (en) * | 2018-09-12 | 2019-01-11 | 杰华特微电子（杭州）有限公司 | Switching Power Supply and its control circuit and control method |
| CN109462398A (en) * | 2018-10-31 | 2019-03-12 | 北京大学（天津滨海）新代信息技术研究院 | A kind of low-power consumption reference voltage circuit system based on dynamic compensation |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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