CN107508456A - A kind of switching power source control circuit, switching power circuit, start method - Google Patents
A kind of switching power source control circuit, switching power circuit, start method Download PDFInfo
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- CN107508456A CN107508456A CN201710558806.6A CN201710558806A CN107508456A CN 107508456 A CN107508456 A CN 107508456A CN 201710558806 A CN201710558806 A CN 201710558806A CN 107508456 A CN107508456 A CN 107508456A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/36—Means for starting or stopping converters
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
This disclosure relates to a kind of switching power source control circuit, switching power circuit, startup method.The control circuit of the disclosure is flowed through the current maxima in primary side inductance coil by control, it is increased relative to current peak in primary side inductance coil during Switching Power Supply normal work in one section of duration of Switching Power Supply electrifying startup, and then realizes quick start.After one section of duration of Switching Power Supply electrifying startup, by making to flow through the current maxima in primary side inductance coil, the current peak flowed through when returning to Switching Power Supply normal work in primary side inductance coil, make Switching Power Supply normal work.Using the switching power circuit for being integrated with above-mentioned control circuit chip, chip power access terminal voltage can be made to drop to before chip internal restarts voltage and charged again, quick startup is realized, avoid restarting.
Description
Technical field
This disclosure relates to switch power technology field, specifically, is related to a kind of switching power source control circuit, Switching Power Supply
Circuit, start method.
Background technology
The application of Switching Power Supply is increasingly extensive at present, and prior art switch power circuit diagram is as shown in figure 1, bag
Include primary side inductance coil LP, secondary inductance coil LS, auxiliary induction coil Laux, power charging circuit, ON-OFF control circuit, open
Close power supply control chip IC.The primary side inductance coil LP, secondary inductance coil LS, auxiliary induction coil Laux form transformation
Electric energy, is converted into magnetic energy, secondary inductance coil discharge or demagnetization, then magnetic energy is converted into electricity by device, primary side inductance coil charging
Energy.The power charging circuit includes the resistance R1 and electric capacity C2 of series connection, connection end and the auxiliary of the resistance R1 and electric capacity C2
Inductance coil Laux in-phase end is connected by diode D2.The ON-OFF control circuit includes switching tube Q1 and sampling resistor
R4。
As shown in Fig. 2 the t0 moment electric system is firm, the power end VCC of the Switching Power Supply control chip IC starts
Charging, now power consumption is microampere rank inside Switching Power Supply control chip IC.At the t1 moment, Switching Power Supply control chip IC chargings
Reach internal and start voltage.Now, Switching Power Supply control chip IC starts working, its internal power consumption can reach hundreds of microamperes with
On, its power end VCC is begun to decline.Because electric capacity C2 starts to discharge, and output capacitor C5 is started to charge up, secondary inductance coil
LS output end voltages Vout is begun to ramp up.Assuming that ignore diode D2, D4 tube voltage drop, when secondary inductance coil LS output end voltages
Vout is risen to when making formula (1) establishment, and auxiliary induction coil Laux gives electric capacity C2 to charge by D2, now, Switching Power Supply control
The power end Vcc voltage of chip IC rises again.
In formula：Ns, Naux are respectively secondary inductance coil LS, auxiliary induction coil Laux coil turn, and Vcc is switch
Power supply control chip IC power ends VCC voltage, Vout are the voltage of secondary inductance coil LS output ends.
For above-mentioned switching power circuit, when the speed of electric capacity C2 electric discharges, electric capacity C5 chargings can not realize the requirement of formula (1)
When, i.e. secondary inductance coil LS output end voltages Vout meets formula (2), and Switching Power Supply control chip IC power supply terminal voltage
Vcc is had dropped to inside Switching Power Supply control chip IC when restarting voltage uvlo (on), then Switching Power Supply control chip IC meetings
It is into rebooting status, i.e., as shown in Figure 3.
It is above-mentioned it is this restart in Switching Power Supply be do not allow occur.Due on the premise of requiring that stand-by power consumption is low,
Starting resistance R1, to be unable to value too small, thus in the case where guaranteeing starting with full load and will not restart, reduces Switching Power Supply control
The power supply terminal voltage VCC ends electric capacity C2 values of chip IC processed, reduce and start the time, start quickly, make Switching Power Supply control chip
IC power end voltage vcc charges before voltage uvlo (on) dropping to inside Switching Power Supply control chip IC to restart again,
Realize that secondary inductance coil LS output end voltages meet that formula (1) is that to solve the problems, such as at present.
The content of the invention
In view of the above-mentioned problems, the disclosure proposes a kind of switching power source control circuit, switching power circuit.Wherein, the control
Circuit processed obtains sampling resistor input terminal voltage as sampled voltage, when the sampled voltage reaches threshold voltage, the control
Circuit control power tube cut-off processed.For convenience of use, the control circuit can be integrated on chip.Using the control circuit
Switching Power Supply, in one section of duration of electrifying startup, due to improving the current peak flowed through in primary side inductance coil, quite
In the conducting duration for extending primary side inductance coil, dutycycle is improved, so as to ensure that Switching Power Supply control chip opens fully loaded
Without restarting when dynamic.After this section of duration, the current maxima flowed through in primary side inductance coil returns to power supply normal work
The maximum of state, power supply enter normal operating conditions.Finally, the disclosure gives one kind on Switching Power Supply in background technology
Startup method.
The present invention includes any order and/or any combination of following aspect/embodiment/feature.
A kind of switching power source control circuit, the control circuit obtain the voltage of power tube output end, using the voltage as
Sampled voltage；Each cycle in the first duration, when the sampled voltage reaches first threshold voltage, the control circuit
Output driving control signal；Each cycle after the first duration, when the sampled voltage reaches second threshold voltage, institute
State control circuit output driving control signal；First duration, first threshold voltage, second threshold voltage can set tune
It is whole.
Control circuit in foregoing or embodiments below/feature/aspect, wherein, the control circuit includes timing electricity
Road, peak current control circuitry, logic circuit, drive circuit；Wherein：The timing circuit on the control circuitry electricity after counted
When, in the first duration, the first timing signal is exported, after the first duration, exports the second timing signal；According to the first timing
Signal, when sampled voltage reaches first threshold voltage, the peak current control circuitry exports peak control signal；According to
Two timing signals, when sampled voltage reaches second threshold voltage, the peak current control circuitry exports peak control signal；
According to the peak control signal, the logic circuit output accounts for logical signal；According to the logical signal, the drive circuit
Output driving control signal.
Control circuit in foregoing or embodiments below/feature/aspect, wherein, the peak current control circuitry
Input is connected with one end of timing circuit；The output end of the peak current control circuitry is connected with one end of logic circuit；
The other end of the logic circuit is connected with one end of drive circuit；Control of the other end of the drive circuit as control circuit
End processed；Sampling end of the sampling input of the peak current control circuitry as control circuit.
Control circuit in foregoing or embodiments below/feature/aspect, the peak current control circuitry include selection
Circuit and comparison circuit；The selection circuit selects first threshold voltage according to the first timing signal, according to the second timing signal
Select second threshold voltage；The comparison circuit is used to be compared according to the threshold voltage and sampled voltage of selection, and according to
Comparative result exports peak control signal.
Control circuit in foregoing or embodiments below/feature/aspect, the first threshold of the selection circuit connection setting
Threshold voltage and second threshold voltage, output end connect an input of comparison circuit；Another input of the comparison circuit
Hold as the sampling end of the peak current control circuitry；One end of the output end connection logic circuit of the comparison circuit.
Control circuit in foregoing or embodiments below/feature/aspect, the control circuit also include start-up circuit,
For setting the startup of control circuit and shut-off parameter, and when upper electric, give timing circuit one beginning timing signal.
Control circuit in foregoing or embodiments below/feature/aspect, the control circuit are integrated in the chips；Institute
State the power end of start-up circuit connection chip；The sampling end of the peak current control circuitry connection chip；The drive circuit
Connect the drive end of chip.
A kind of switching power circuit, the switching power circuit include control circuit, power tube；The control circuit is upper
Any described control circuit is stated, the voltage that it is used to obtain power tube output end is as sampled voltage；In the first duration, when
When the sampled voltage is higher than first threshold voltage, or after the first duration, when the sampled voltage is higher than Second Threshold
During voltage, the control circuit control power tube cut-off；The first threshold voltage is more than second threshold voltage.
A kind of startup method of Switching Power Supply, methods described comprise the steps：
S1, each cycle in the first duration, the voltage of power tube output end is obtained as sampled voltage, is adopted when described
When sample voltage is higher than first threshold voltage, control power tube cut-off；
S2, each cycle after the first duration, the voltage of power tube output end are obtained as sampled voltage, when described
When being higher than second threshold voltage using voltage, control power tube cut-off；
The first threshold voltage is more than second threshold voltage；
Wherein, first duration, first threshold voltage, second threshold voltage can set adjustment.
In the above-mentioned methods, wherein first duration is more than or equal to 5ms.
Compared with prior art, the disclosure has following advantageous effects：
The control circuit of the disclosure can select the threshold voltage compared with sampled voltage stage by stage, and the sampled voltage is just
Than the electric current flowed through in primary side inductance coil.When being higher than threshold voltage by sampled voltage, the cut-off of power tube is controlled, and then
The size of current flowed through in control primary side inductance coil.Using control circuit or the Switching Power Supply for the chip for being integrated with control circuit
Circuit, the sampling electricity of electric current in primary side inductance coil in upper one section of electric duration, can be proportional to by control circuit detection
Pressure is higher than first threshold voltage, control power tube cut-off.Because first threshold voltage is larger, the electricity that is flowed through in primary side inductance coil
Stream peak value increases relative to current peak during normal work, and it is maximum accordingly to improve the electric current flowed through in secondary inductance coil
Value, that is, increase the charging current of switched power output, thus can reduce the electricity being connected with control circuit power access end VCC
Hold C2 values, reduce and start the time.Similarly, after one section of duration electric in Switching Power Supply, it is higher than the second threshold in sampled voltage
During threshold voltage, control power tube cut-off.It is normal that power supply is returned to by current value in second threshold voltage control primary side inductance coil
The maximum of working condition, power supply enter normal operating conditions.Using the Switching Power Supply for being integrated with above-mentioned control circuit chip
Circuit, chip power access terminal voltage can be made to drop to before chip internal restarts voltage and charged again, reach background technology portion
Divide the requirement of Chinese style (1), realize quick startup, avoid restarting.
Brief description of the drawings
Fig. 1 is prior art switching power circuit figure；
Fig. 2 is prior art Switching Power Supply start-up circuit timing diagram；
Fig. 3 is that prior art Switching Power Supply start-up circuit IC restarts timing diagram；
Fig. 4 is a kind of control circuit structural representation in one embodiment of the invention；
Fig. 5 is the peak current control circuitry structural representation in one embodiment of the invention；
Fig. 6 is another control circuit structural representation in one embodiment of the invention；
Fig. 7 is the Switching Power Supply fast circuit schematic diagram in one embodiment of the invention；
Fig. 8 is the Switching Power Supply fast start circuit timing diagram in one embodiment of the invention.
Embodiment
Present disclosure is described in detail 1- Fig. 8 below in conjunction with the accompanying drawings.
In one embodiment, there is provided a kind of switching power source control circuit, the control circuit obtain power tube output
The voltage at end, using the voltage as sampled voltage；Each cycle in the first duration, when the sampled voltage is higher than the first threshold
During threshold voltage, the control circuit output driving control signal；Each cycle after the first duration, when the sampled voltage
During higher than second threshold voltage, the control circuit output driving control signal；First duration, first threshold voltage,
Two threshold voltages can set adjustment.
In this embodiment, the control circuit includes two threshold voltages, for being compared with sampled voltage.This
The output of two threshold voltages is relevant with the first duration, and size can adjust, and the time span of the first duration can also adjust.
In one embodiment, the control circuit includes timing circuit, peak current control circuitry, logic circuit, drive
Dynamic circuit；Wherein：The timing circuit on the control circuitry electricity after carry out timing, in the first duration, output the first timing letter
Number, after the first duration, export the second timing signal；According to the first timing signal, when sampled voltage is higher than first threshold electricity
During pressure, the peak current control circuitry exports peak control signal；According to the second timing signal, when sampled voltage is higher than second
During threshold voltage, the peak current control circuitry exports peak control signal；According to the peak control signal, the logic
The different logical signal of circuit output dutycycle；According to the logical signal, the drive circuit output driving control signal.
Fig. 4 provides a kind of preferred circuit connected mode of above-mentioned control circuit.Wherein, the peak current control circuitry
(20) input is connected with the one end of timing circuit (30)；The output end of the peak current control circuitry (20) and logic electricity
The one end on road (50) is connected；The other end of the logic circuit (50) is connected with one end of drive circuit (60)；The driving electricity
Control terminal of the other end on road (60) as control circuit；The sampling end of the peak current control circuitry (20) is as control electricity
The sampling end on road.
In one embodiment, the peak current control circuitry includes selection circuit and comparison circuit；The selection electricity
Road selects first threshold voltage according to the first timing signal, and second threshold voltage is selected according to the second timing signal；The comparison
Circuit is used to be compared according to the threshold voltage and sampled voltage of selection, and exports peak control signal after the comparison.
Fig. 5 gives a kind of circuit structure of preferably peak current control circuitry.Wherein, the selection circuit (P2) connects
An input of comparison circuit (P1) is connect, the sampling end of another input connection control circuit of comparison circuit (P1) is used for
Receive sampled voltage (Vcs), the input of its output end connection logic circuit (50).The selection circuit (P2) is believed according to timing
Number (A2) determines the threshold value for comparing.Threshold value for comparing includes the first threshold voltage (Vth1) and Second Threshold of setting
Voltage (Vth2).The comparison circuit (P1) be used for be compared according to the threshold value and sampled voltage (Vcs) of determination, and according to than
Relatively result output peak control signal (A3).
In one embodiment, the control circuit also includes start-up circuit, for setting startup and the pass of control circuit
Disconnected parameter, and when upper electric, give timing circuit one beginning timing signal.
Wherein, the other end of the timing circuit (30) is connected with one end of start-up circuit (40)；The start-up circuit
(40) power access end of the other end as control circuit.
In one embodiment, the control circuit is integrated in the chips；The power end of the start-up circuit connection chip；
The sampling end of the peak current control circuitry connection chip；The drive end of the drive circuit connection chip.
Fig. 6 illustrates a kind of preferable control circuit attachment structure.Wherein, the electricity of start-up circuit (40) one end connection chip
Source (VCC), the other end connect one end (30) of timing circuit.The other end connection peak value comparison method electricity of timing circuit (30)
The input (20) on road, the sampling end (CS) of another input connection control chip of peak current control circuitry, output end
One end of logic circuit (50) is connected, the other end of logic circuit (50) connects one end of drive circuit (60), drive circuit
The other end connects the drive end (DRIVER) of chip.
On start-up circuit (40) after electricity, an enabling signal (A1) is exported, timing circuit (30) starts timing, output meter
When signal (A2).Peak current control circuitry (20) receives timing signal (A2), and according to timing signal (A2) and sampling electricity
Press (Vcs) output peak control signal (A3).Logic circuit (50) is according to peak control signal (A3) output logic signal (A4).
Drive circuit (60) is according to logical signal (A4) output driving control signal (DRIVER).
Control circuit in Fig. 6 can integrate in the chips.
In one embodiment, there is provided a kind of switching power circuit, the switching power circuit include control circuit, work(
Rate pipe；The control circuit is any of the above-described control circuit, and the voltage that it is used to obtain power tube output end is as sampling
Voltage；In the first duration, when the sampled voltage is higher than first threshold voltage, or after the first duration, when described
When sampled voltage is higher than second threshold voltage, the control circuit control power tube cut-off；The first threshold voltage is more than the
Two threshold voltages.
In Switching Power Supply, power tube output end is connected with sampling resistor one end, the other end ground connection of sampling resistor.Obtain
The voltage of power tube output end, that is, obtaining the voltage at sampling resistor both ends, with reference to the resistance of sampling resistor, it can obtain
Flow through the electric current of sampling resistor.When power tube turns on, electricity of the size of current with flowing through sampling resistor in primary side inductance coil
Stream size is identical, thus can detect the size of current in primary side inductance coil.
Fig. 7 illustrates the connection of the power tube of control circuit and Switching Power Supply in Fig. 6, sampling resistor, control electricity
Road is integrated into chip.Wherein, the input of the sampling end (CS) of chip, the output end of power tube (Q1) and sampling resistor (R4)
End is connected；The output end of the power tube (Q1) is connected with one end of sampling resistor (R4), the sampling resistor (R4) it is another
End ground connection；The control terminal of the power tube (Q1) is connected with the drive end (DRIVER) of control circuit chip；The power tube
(Q1) input is connected with the one end of primary side inductance coil (Lp).
Fig. 8 illustrates as shown using the Switching Power Supply fast start circuit timing diagram of above-mentioned control circuit.Assuming that first
Threshold voltage (Vth1) is more than second threshold voltage (Vth2).Start timing on startup, when timing duration is less than the first duration
When, in a cycle, by the sampled voltage (Vcs) on sampling resistor (R4) compared with first threshold voltage (Vth1),
Power tube (Q1) shut-off is controlled when sampled voltage (Vcs) is more than or equal to first threshold voltage (Vth1)；When timing duration is more than
During equal to setting duration, in a cycle, the sampled voltage (Vcs) on sampling resistor is entered with second threshold voltage (Vth2)
Row compares, and power tube (Q1) shut-off is controlled when sampled voltage (Vcs) is more than or equal to second threshold voltage (Vth2).
Because first threshold voltage is more than second threshold voltage, the maximum current flowed through on primary side inductance coil (Lp)
(Ipk) in setting duration, current peak during with respect to Switching Power Supply normal work increases, equivalent to extending primary side inductor wire
The ON time of (Lp) is enclosed, improves dutycycle.
After sampling resistor (R4) determination, sampled voltage (Vcs) is proportional to the electric current flowed through on primary side inductance coil (Lp)
(Ip), when maximum current (Ipk) increase flowed through on primary side inductance coil (Lp), flow through on secondary inductance coil (Ls) most
High current (Isk) also increases；The increase of the maximum current (Isk) flowed through on secondary inductance coil (Ls), exports Switching Power Supply
Hold the charging current increase of electric capacity (C5), overload protection point electric current (Iolp) increase of system, so that secondary inductance coil is defeated
Go out terminal voltage (Vout) and be rapidly achieved following formula condition, realize quick startup, and avoid Switching Power Supply from restarting：
In formula：Ns, Naux are respectively secondary inductance coil LS, auxiliary induction coil Laux coil turn, and Vcc is control
Circuit power incoming end VCC voltage, Vout are the voltage of secondary inductance coil LS output ends.
It is DCM patterns in the mode of operation of Switching Power Supply according to the operation principle of Switching Power Supply, dutycycle 50%, i.e.,
Tons=T/2, wherein Tons are that transformer secondary demagnetizes the time, and T is cycle time.If Toffs is in transformer a cycle
Time of the secondary in addition to the time of demagnetizing, then Toffs=T-Tons, so that following formula is set up：
Wherein, Iolp is the overload protection point electric current of system, and Ipk represents primary side induction coil current maximum, and Np is represented
The primary side inductance coil number of turn, Isk represent secondary inductance coil current maximum, and Ns represents secondary inductance coil turn.Work as primary side
During the current maxima Ipk increases of inductance coil (Lp), the current maxima Isk in secondary inductance coil (Ls) also increases, and is
The overload protection point electric current Iolp of system also increases, when switched power output connects Constant Current Load, it is assumed that load, which is fully loaded with, is
Iload, then if to output capacitance (C5) charging current be Ich, Ich=Iolp-Iload when starting, so startup when it is defeated
Go out the increase of electric capacity (C5) charging current, the voltage (Vout) of secondary inductance coil (Ls) output end rises soon.If Switching Power Supply is adopted
With the chip for integrating above-mentioned control circuit, then it can ensure in fully loaded lower startup and will not restart, and chip power can be reduced
The value of the electric capacity (C2) of incoming end (VCC) connection, reduces starting duration (t1-t0), start quickly, in chip power incoming end
Voltage drops to before (uvlo (on)), realizesAfter this period, reducing threshold voltage makes inductance
The current maxima flowed through in coil (Lp) returns to the maximum of power supply normal operating conditions, and power supply enters normal operating conditions.
When Switching Power Supply output connects constant pressure load, the load current of Startup time is equivalent to zero, then output capacitance
(C5) charging current (Ich) is equal to overload protection point electric current (Iolp), and output capacitance (C5) charging interval is very short.If Switching Power Supply
Switching Power Supply control chip is integrated with above-mentioned control circuit, does not have to worry that Switching Power Supply control chip is restarted when connecing constant pressure load
With the mutual restricting relation before the startup time.
The first duration being related in foregoing embodiments/feature/aspect, preferably greater than or equal to 5ms.
A kind of startup method of Switching Power Supply, methods described comprise the steps：
S1, each cycle in the first duration, the voltage of power tube output end is obtained as sampled voltage, is adopted when described
When sample voltage is higher than first threshold voltage, control power tube cut-off；
S2, each cycle after the first duration, the voltage of power tube output end are obtained as sampled voltage, when described
When being higher than second threshold voltage using voltage, control power tube cut-off；
The first threshold voltage is more than second threshold voltage；
Wherein, first duration, first threshold voltage, second threshold voltage can set adjustment.
In the above-mentioned methods, wherein first duration is more than or equal to 5ms.
In this embodiment, specific circuit structure is not concerned with, the Switching Power Supply includes primary side inductance coil, secondary
Inductance, power tube.The Switching Power Supply is turned on and ended come controlling switch pipe by control circuit, when power tube turns on
When, the charging of primary side inductance coil；When power tube ends, secondary inductance coil discharge.It is preferred that use foregoing embodiments/spy
Power circuit in sign/aspect.
Embodiment described above is only the preferred embodiments of the present invention, therefore can not be interpreted as to the scope of the invention
Limitation, it is noted that to those skilled in the art, without departing from the inventive concept of the premise, can be with
Several modifications and improvements are made, these belong to protection scope of the present invention.
Claims (10)
- A kind of 1. switching power source control circuit, it is characterised in that：The control circuit obtains the voltage of power tube output end, using the voltage as sampled voltage；Each cycle in the first duration, when the sampled voltage is higher than first threshold voltage, the control circuit output Driving control signal；In each cycle after the first duration, when the sampled voltage is higher than second threshold voltage, the control circuit is defeated Go out driving control signal；First duration, first threshold voltage, second threshold voltage can set adjustment.
- 2. control circuit according to claim 1, it is characterised in that：Preferably,The control circuit includes timing circuit, peak current control circuitry, logic circuit, drive circuit；Wherein：The timing circuit on the control circuitry electricity after carry out timing, in the first duration, export the first timing signal, first After duration, the second timing signal is exported；According to the first timing signal, when sampled voltage is higher than first threshold voltage, the peak current control circuitry exports peak It is worth control signal；According to the second timing signal, when sampled voltage is higher than second threshold voltage, the peak current control circuitry exports peak It is worth control signal；According to the peak control signal, the logic circuit output logic signal；According to the logical signal, the drive circuit output driving control signal.
- 3. control circuit according to claim 2, it is characterised in that：The input of the peak current control circuitry is connected with one end of timing circuit；The output end of the peak current control circuitry is connected with one end of logic circuit；The other end of the logic circuit is connected with one end of drive circuit；Control terminal of the other end of the drive circuit as control circuit；Sampling end of the sampling input of the peak current control circuitry as control circuit.
- 4. control circuit according to claim 2, it is characterised in that：The peak current control circuitry includes selection circuit and comparison circuit；The selection circuit selects first threshold voltage according to the first timing signal, and Second Threshold is selected according to the second timing signal Voltage；The comparison circuit is used to be compared according to the threshold voltage and sampled voltage of selection, and exports peak according to comparative result It is worth control signal.
- 5. control circuit according to claim 4, it is characterised in that：The first threshold voltage and second threshold voltage of the selection circuit connection setting, one of output end connection comparison circuit Input；Another input of the comparison circuit is the sampling end of the peak current control circuitry；One end of the output end connection logic circuit of the comparison circuit.
- 6. according to any described control circuits of claim 2-5, it is characterised in that：The control circuit also includes start-up circuit, for setting the startup of control circuit and shut-off parameter, and when upper electric, gives One beginning timing signal of timing circuit.
- 7. control circuit according to claim 6, it is characterised in that：The control circuit is integrated in the chips；The power end of the start-up circuit connection chip；The sampling end of the peak current control circuitry connection chip；The drive end of the drive circuit connection chip.
- A kind of 8. switching power circuit, it is characterised in that：The switching power circuit includes control circuit, power tube；The control circuit is any described control circuits of claim 1-7, and it is used for the voltage for obtaining power tube output end As sampled voltage；In the first duration, when the sampled voltage is higher than first threshold voltage, or after the first duration, adopted when described When sample voltage is higher than second threshold voltage, the control circuit control power tube cut-off；The first threshold voltage is more than second threshold voltage.
- 9. a kind of startup method of Switching Power Supply, it is characterised in that methods described comprises the steps：S1, each cycle in the first duration, the voltage of power tube output end are obtained as sampled voltage, when the sampling electricity When pressure is higher than first threshold voltage, control power tube cut-off；S2, each cycle after the first duration, the voltage of power tube output end are obtained as sampled voltage, when the use When voltage is higher than second threshold voltage, control power tube cut-off；The first threshold voltage is more than second threshold voltage；Wherein, first duration, first threshold voltage, second threshold voltage can set adjustment.
- 10. according to the method for claim 9, it is characterised in that：First duration is more than or equal to 5ms.
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| CN201710558806.6A CN107508456B (en) | 2017-07-10 | 2017-07-10 | Switching power supply control circuit, switching power supply circuit and starting method |
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| CN201710558806.6A CN107508456B (en) | 2017-07-10 | 2017-07-10 | Switching power supply control circuit, switching power supply circuit and starting method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108429446A (en) * | 2018-04-02 | 2018-08-21 | 陕西亚成微电子股份有限公司 | A kind of power supply method for restarting and circuit |
| CN109408293A (en) * | 2018-11-02 | 2019-03-01 | 郑州云海信息技术有限公司 | A kind of method of real-time monitoring RACK cabinet power supply |
| CN109669061A (en) * | 2019-01-31 | 2019-04-23 | 广州金升阳科技有限公司 | A kind of current sample compensation circuit |
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| CN108429446B (en) * | 2018-04-02 | 2024-05-03 | 陕西亚成微电子股份有限公司 | Power restarting method and circuit |
| CN109408293A (en) * | 2018-11-02 | 2019-03-01 | 郑州云海信息技术有限公司 | A kind of method of real-time monitoring RACK cabinet power supply |
| CN109669061A (en) * | 2019-01-31 | 2019-04-23 | 广州金升阳科技有限公司 | A kind of current sample compensation circuit |
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