CN107302306A - A kind of Switching Power Supply - Google Patents
A kind of Switching Power Supply Download PDFInfo
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- CN107302306A CN107302306A CN201710497391.6A CN201710497391A CN107302306A CN 107302306 A CN107302306 A CN 107302306A CN 201710497391 A CN201710497391 A CN 201710497391A CN 107302306 A CN107302306 A CN 107302306A
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- Prior art keywords
- voltage
- power supply
- current
- transistor
- switching power
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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
- H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
Abstract
A kind of Switching Power Supply, the Switching Power Supply include inductance, main switch, the controlled on or off of main switch so that Switching Power Supply output end output have output voltage, the Switching Power Supply also includes：With the tie point of inductance in parallel, tie point includes the first switch of series connection and ring suppresses resistance, and the connecting node of inductance and main switch is designated as switching node；Detection module, is adapted to detect for whether association voltage is less than threshold voltage, and its output end output testing result, association voltage is associated with the voltage of switching node；Logic module, its first input end couples the output end of detection module, its second input couples the control end of main switch, when main switch controlled shutdown and testing result indicate that association voltage is less than threshold voltage, logic module control first switch conducting is until the controlled conducting of main switch, otherwise, logic module control first switch shut-off.The present invention program can suppressed ringing, and cost is low, and stability is high.
Description
Technical field
The present invention relates to Power Management Design field, more particularly to a kind of Switching Power Supply.
Background technology
Switching Power Supply is to utilize modern power electronics technology, the time ratio that controlling switch pipe is turned on and off, and remains steady
Determine a kind of power supply of output voltage.Switching power converters it is general by pulse width modulation (Pulse Width Modulation,
Abbreviation PWM) control circuit, energy-storage travelling wave tube (such as inductance) and switching tube composition.Substantial amounts of switch electricity can be used in mobile terminal
Source converter, modules such as central processing unit (Central Processing Unit, abbreviation CPU), client to its inside
There is provided steady for identification module (Subscriber Identification Module, abbreviation SIM) card, radio-frequency power amplifier etc.
Determine power supply.
Fig. 1 shows a kind of Switching Power Supply 100 of switch DC booster type, and the Switching Power Supply 100 can include inductance
L1, main switch M1, the electric capacity C1 of sustained diode 1 and first.The Switching Power Supply 100 accesses input voltage VIN, and the master opens
The controlled on or off of M1 is closed, so that the output of Switching Power Supply 100 has output voltage VO UT, output voltage VO UT to be supplied for load
Electricity.When the electric current of load is smaller or does not have load current, such as electronic equipment enters standby or dormancy, switch
Power supply 100 typically can all reduce working frequency, into discontinuous conduction mode (Discontinuous Conduction Mode,
Abbreviation DCM).Under DCM, general load current is smaller, and working frequency is lower.Now, the company of the inductance L1 and main switch M1
Serious inductance (Inductor, abbreviation L) electric capacity (Capacity, abbreviation C) vibration may occur at contact SW, produce ring and show
As, and then trigger serious electromagnetic interference (Electromagnetic Interference, abbreviation EMI) problem.
A kind of method of suppressed ringing is to seal in magnetic between the input and inductance L1 of Switching Power Supply 100 in the prior art
Pearl L2, but this can cause system cost to increase；In addition, when the parameter of the magnetic bead L2 is not provided with appropriate, may result in all
Such as system device is uttered long and high-pitched sounds extremely, namely generates the vibration for falling into audiorange (20Hz-20kHz).
The content of the invention
Present invention solves the technical problem that being that reduction system cost is simultaneously how in the ringing in suppressing Switching Power Supply
Avoidance system is abnormal.
In order to solve the above technical problems, the embodiment of the present invention provides a kind of Switching Power Supply, the Switching Power Supply include inductance,
Main switch, the controlled on or off of main switch, so that the output end output of the Switching Power Supply has output voltage；It is described to open
Powered-down source also includes：With the tie point of the inductance in parallel, the tie point includes first switch and the ring suppression of series connection
Resistance processed, the connecting node of the inductance and main switch is designated as switching node；Whether small detection module, be adapted to detect for association voltage
In threshold voltage, its output end output testing result, the association voltage is associated with the voltage of the switching node；Logic mould
Block, its first input end couples the output end of the detection module, and its second input couples the control end of the main switch, when
When the main switch controlled shutdown and the testing result indicate that the association voltage is less than the threshold voltage, the logic mould
Block controls the first switch conducting until the controlled conducting of the main switch, otherwise, the logic module control described first are opened
Shut-off.
Alternatively, the threshold voltage is less than 0V.
Alternatively, the detection module includes：First current branch, suitable for producing default first reference current, and is passed through
Exported by its output end；Second current branch, compares electric current, and export via its output end suitable for being produced according to association voltage；
Wherein, first reference current be more than or equal to it is described compare electric current when, the testing result be the first logic level, with refer to
Show it is described association voltage be more than or equal to the threshold voltage, first reference current be less than it is described compare electric current when, it is described
Testing result is the second logic level different from first logic level, to indicate that the association voltage is less than the threshold value
Voltage.
Alternatively, first current branch includes：First current mirror, suitable for carrying out mirror image to the second reference current, with
Obtain the first reference current；Second current branch includes：Second current mirror, suitable for being obtained according to the 3rd reference current mirror image
Described to compare electric current, the current value of the 3rd reference current is equal to the current value of second reference current, second electricity
Flowing mirror includes the first transistor and second transistor, and the first transistor accesses the 3rd reference current, and described second is brilliant
The output end output of body pipe is described to compare electric current, and the input of the second transistor accesses the association voltage；Wherein, it is described
The ratio of second reference current and first reference current is less than the breadth length ratio and second crystal of the first transistor
The ratio of the breadth length ratio of pipe.
Alternatively, the first transistor and second transistor are nmos pass transistor, and first current mirror includes the 3rd
The transistor of transistor AND gate the 4th, the third transistor is PMOS transistor with the 4th transistor.
Alternatively, second current branch also includes：3rd current mirror, suitable for carrying out mirror to second reference current
Picture, to obtain the 3rd reference current, and is exported via its output end.
Alternatively, the 3rd reference current is equal to first reference current.
Alternatively, the detection module also includes：Potential-divider network, its first input end couples the switching node, and it the
Two inputs couple reference edge, and its partial pressure output end exports the association voltage.
Alternatively, the logic module includes：D type flip flop, its reset terminal couples the control end of the main switch, its data
Input accesses the first control voltage, and its data output end couples the control end of the first switch, and the coupling of its clock end is described
The output end of detection module；Wherein, in the controlled conducting of the main switch, the d type flip flop resets, to cause described first to open
Close controlled shutdown；Indicate that the association voltage is less than the threshold voltage in the main switch controlled shutdown and the testing result
When, the data output end of the d type flip flop exports first control voltage, to cause the controlled conducting of the first switch until
The controlled conducting of the main switch.
Alternatively, the first switch is suitable to controlled conducting, first control voltage when its control end is high level
For the input voltage of the Switching Power Supply.
Compared with prior art, the technical scheme of the embodiment of the present invention has the advantages that：
The Switching Power Supply of the embodiment of the present invention is by detecting the association voltage (electricity of the association voltage and the switching node
Pressure is associated) whether it is less than threshold voltage to judge whether to occur ringing, once detecting ringing, then control first
Switch conduction, to cause inductance and ring to suppress resistance formation path, to evade the generation of LC vibrations, suppressed ringing phenomenon changes
It is apt to the EMI of the Switching Power Supply.Relative to prior art, with system cost is low and the high advantage of stability.
Furthermore, the detection module can include the first current branch for producing default first reference current and
The second current branch for comparing electric current is produced according to association voltage, wherein, it is more than or equal to the ratio in first reference current
During compared with electric current, the testing result is the first logic level, to indicate that the association voltage is more than or equal to the threshold voltage,
First reference current is less than described when comparing electric current, and the testing result is different from the second of first logic level
Logic level, to indicate that the association voltage is less than the threshold voltage.That is, what the present invention program was compared by electric current
Mode occurs ringing to Switching Power Supply and detected, it is easy to implement, cost is low, stability is high.
Brief description of the drawings
Fig. 1 is a kind of circuit diagram of Switching Power Supply of the prior art.
Fig. 2 is a kind of schematic block diagram of Switching Power Supply of the embodiment of the present invention.
Fig. 3 is a kind of circuit diagram of the Switching Power Supply shown in Fig. 2.
Fig. 4 is a kind of working waveform figure of the Switching Power Supply shown in Fig. 2.
Embodiment
As described in the background section, the method for suppressing ringing in Switching Power Supply in the prior art causes system cost
Increase, it is also possible to cause system device to be uttered long and high-pitched sounds wait extremely.
For techniques discussed above problem, the embodiment of the present invention proposes a kind of Switching Power Supply, can be existing with suppressed ringing
As improving the electromagnetic interference (Electromagnetic Interference, abbreviation EMI) of Switching Power Supply.
It is understandable to enable above-mentioned purpose, feature and beneficial effect of the invention to become apparent, below in conjunction with the accompanying drawings to this
The specific embodiment of invention is described in detail.
Referring to Fig. 2, the embodiment of the invention discloses a kind of Switching Power Supply 200.Scheme of the embodiment of the present invention goes for
Polytype Switching Power Supply, with universality.Specifically, the Switching Power Supply 200 can be switch DC booster circuit
(also referred to as Boost circuit), switch DC reduction voltage circuit (also referred to as Buck circuits) or switch DC step-up/step-down circuit (also referred to as Buck-
Boost circuit).
It is understood to one skilled in the art that when the Switching Power Supply 200 is Buck circuits or Buck-Boost circuits
Circuit topology is essentially identical when being Boost circuit with it, and the coupling mode of the part such as inductance, main switch simply in circuit slightly has
Difference, therefore, to put it more simply, the present embodiment is only illustrated by taking Boost circuit as an example.
Switching Power Supply 200 shown in Fig. 2 can include inductance L1, main switch M1, first in parallel with the inductance L1
Road 10, detection module 20 and logic module 30.
Wherein, the controlled on or off of main switch M1, so that the output end output of the Switching Power Supply 200 has output
Voltage VOUT, the output voltage VO UT are for load supplying.The control end incoming control signal PWM of the main switch M1,
The control signal PWM can be pulse-width signal, to cause the Switching Power Supply 200 to have switch periods.Specific real
Shi Zhong, the main switch M1 can be power switch pipe.Specifically, it can be the NMOS tube shown in Fig. 2, but not limited to this, example
Such as, the main switch M1 can also be PMOS, triode etc., only need to suitably adjust the control strategy to the main switch M1
.
When the controlled conductings of the main switch M1, the input voltage VIN of the Switching Power Supply 200 via the inductance L1 and
Main switch M1 extremely formed on electric pathway, the inductance L1 because stream has an electric current and constantly energy storage；Closed when the main switch M1 is controlled
When disconnected, the electric energy stored by the inductance L1 is transmitted to the output end.Furthermore, the Switching Power Supply 200 can be with
Including synchro switch (referring to the sustained diode 1 in Fig. 2) and the first electric capacity C1.Electric energy stored by the inductance L1 is institute
The first electric capacity C1 chargings are stated, to cause the voltage on the output end and the switching node SW to raise, while the inductance
Electric energy stored by L1 is reduced.Under the control of the control signal PWM switching regulators, the Switching Power Supply 200 is again and again
Work.
Nowadays, electronic equipment has the development trend of low-power consumption.When application switch power supply electronic equipment be in it is standby or
During dormant state, the load current reduction of Switching Power Supply, equipment meeting controlling switch power supply enters discontinuous conduction mode
(Discontinuous Conduction Mode, abbreviation DCM), and reduce the switching frequency of Switching Power Supply.
When the Switching Power Supply 200 enters DCM patterns, during the main switch M1 controlled shutdowns, the inductance L1
Electric energy release when finishing, it may produce resonance with the parasitic capacitance of the main switch M1, and the phenomenon can be referred to as ring
(Ringing) phenomenon, produced inductance (Inductor, abbreviation L) electric capacity (Capacity, abbreviation C), which vibrates, causes described open
The EMI problems in powered-down source 200 are serious.
When occurring due to vibration, acute variation can occur for the voltage of the switching node SW, therefore, and the present embodiment is for upper
State LC vibrations detect, and be provided with corresponding energy release path, to evade the generation of above-mentioned LC vibrations, suppression
Ringing processed.
The tie point 10 forms above-mentioned energy release path.Specifically, the tie point 10 can include string
The first switch S1 of connection and ring suppress resistance Ring, and the connecting node of the inductance L1 and main switch M1 are designated as switching node
SW.As long as the first switch S1 and ring suppress resistance Ring series connection, the present embodiment does not limit its specifically connection side
Formula.
In specific implementation, the first switch S1 can be the semiconductor switch devices such as metal-oxide-semiconductor, triode, can also
For any other switching device or switch chip, the present embodiment is without specifically limited.Preferably, the first switch S1 is
NMOS tube so that the Switching Power Supply 200 has more preferable integrated level, and is easy to control.
The generation being provided for ringing of the detection module 20 is detected.Specifically, the detection module
20 are adapted to detect for whether association voltage SWT is less than threshold voltage, its output end output testing result Vcmp, the association voltage
SWT (be represented by dashed line in Fig. 2 the two be associated) associated with the voltage of the switching node SW, for example, the two can with equal,
Or the association voltage SWT can be obtained through the voltage of the switching node SW, then or, the association voltage SWT
It can be obtained through the voltage bias of the switching node SW.
In general, during the normal work of Switching Power Supply 200, the voltage of the switching node SW is typically
More than zero, when occurring ringing, violent vibration, in oscillatory process, institute can occur for the voltage of the switching node SW
Below 0V can be dropped to by stating switching node SW voltage.Because the association voltage SWT is opened described in below 0V based on dropping to
Artis SW voltage is changed, and when occurring ringing, the association voltage SWT is largely also less than 0V
, therefore, in specific implementation, the threshold voltage can be set to be less than 0V, for example, -1.5V or -2V etc., can be according to reality
The design requirement on border is configured.
By the identification to testing result Vcmp the first switch S1 in the tie point 10 can be controlled to turn on, with
So that the inductance L1 and the ring suppress resistance Ring formation paths, to evade the generation of LC vibrations；In addition, according to switch
The operation principle of power supply is understood, during the LC vibrations occur only at main switch M1 controlled shutdowns, therefore, when its controlled conducting
When, the first switch S1 is to disconnect.
Specifically, the first input end of the logic module 30 couples the output end of the detection module 20, namely access
The testing result Vcmp, the second input of the logic module 30 couples the control end of the main switch M1.As the master
It is described to patrol when switching M1 controlled shutdowns and the testing result Vcmp and indicating that the association voltage SWT is less than the threshold voltage
Collect module 30 and control the first switch S1 conductings until the controlled conductings of the main switch M1, otherwise, the logic module 30 is controlled
Make the first switch S1 shut-offs.
The Switching Power Supply 200 of the embodiment of the present invention is by detecting that (the association voltage SWT is opened association voltage SWT with described
Artis SW voltage is associated) whether it is less than threshold voltage to judge whether to occur ringing, show once detecting ring
As then controlling the first switch S1 to turn on, to cause the inductance L1 and ring to suppress resistance Ring formation paths, to evade
The generation of LC vibrations, suppressed ringing phenomenon improves the EMI of the Switching Power Supply 200.Relative to prior art, with being
Uniting, cost is low and the high advantage of stability.
The embodiment and operation principle of the Switching Power Supply are situated between in detail below with reference to Fig. 2 and Fig. 3
Continue.
In the lump referring to Fig. 2 and Fig. 3, in embodiments of the present invention, the detection module 20 can include the first current branch
(not indicated in figure) and the second current branch (not indicated in figure).
Wherein, first current branch is suitable to produce default first reference current Ir1, and defeated via its output end
Go out；Second current branch, which is suitable to be produced according to association voltage SWT, compares electric current Ic, and is exported via its output end；Assuming that
The first reference current Ir1 charges to the output end of the detection module 20, and the electric current Ic that compares is to the detection module
20 output end electric discharge, the first reference current Ir1 be more than or equal to it is described compare electric current Ic when, the testing result Vcmp
For the first logic level (logically high/low level), to indicate that the association voltage SWT is more than or equal to the threshold voltage, in institute
State the first reference current Ir1 and be less than described when comparing electric current Ic, the testing result is different from first logic level
Second logic level (logic low/high level), to indicate that the association voltage SWT is less than the threshold voltage, namely there occurs
Ringing.
That is, by way of electric current compares to Switching Power Supply 200 ringing can occur for the embodiment of the present invention
Detected, it is easy to implement, cost is low, stability is high.
In specific implementation, first current branch can include the first current mirror (not indicated in figure), described first
Current mirror is suitable to carry out mirror image to the second reference current Ir2, to obtain the first reference current Ir1.Second current branch can
(not indicated in figure) including the second current mirror, second current mirror is suitable to obtain institute according to the 3rd reference current Ir3 mirror images
State and compare current value of electric current Ic, the 3rd reference current Ir3 current value equal to the second reference current Ir2, namely
The first reference current Ir1 and the 3rd reference current Ir3 can be obtained according to same current mirror.In specific implementation
In, the second reference current Ir2 can be produced by the appropriate current source 201 of output current value, or can be by other electricity
Stream mirror (not shown) mirror image is obtained, and the present embodiment is to the source of the second reference current Ir2 without particular determination.
It is understood to one skilled in the art that current mirror can (can be MOS transistor or three poles by a pair of transistor
Pipe) constitute, the present embodiment is illustrated by taking the current mirror that MOS transistor is constituted as an example.The grid of a pair of transistor in current mirror
Extremely it is connected, source electrode is connected；When the breadth length ratio of the two is equal, the electric current of the drain electrode of one of transistor is equal to another crystal
The electric current of the drain electrode of pipe；When the breadth length ratio of the two is unequal, the electric current of the drain electrode of one of transistor and another crystal
The ratio between electric current of drain electrode of pipe is equal to the ratio between breadth length ratio of the two.
In the present embodiment, second current mirror can include the first transistor NM1 and second transistor NM2, described
The first transistor NM1 accesses the 3rd reference current Ir3, output end (namely drain electrode) output of the second transistor NM2
Input (namely source electrode) the access association voltage SWT for comparing electric current Ic, the second transistor NM2.Wherein, institute
The ratio for stating the second reference current Ir2 and the first reference current Ir1 is less than breadth length ratio and the institute of the first transistor NM1
State the ratio of second transistor NM2 breadth length ratio.That is, as the first transistor NM1 in second current mirror and
When two-transistor NM2 source voltage is equal, the second reference current Ir2 and the first reference current Ir1 ratio are small
In the 3rd reference current Ir3 (current value is equal with the second reference current Ir2) and the ratio for being compared electric current Ic.
Namely when the first transistor NM1 and second transistor NM2 source voltage in second current mirror it is equal (for example the two
Source grounding) when, the first reference current Ir1 be more than or equal to it is described compare electric current Ic, and when the association voltage SWT because
When dropping to such as below 0V to occur ringing, between grid and source electrode that the second transistor NM2 can be caused
Voltage rises (grid voltage keeps constant), when the second transistor NM2 is nmos pass transistor, its described of output that drain
Compare electric current Ic to steeply rise, when it is increased over the first reference current Ir1, the inspection that the detection module 20 is exported
Result Vcmp logic level upset is surveyed, to realize the detection to ringing.
It is understood to one skilled in the art that current mirror can be divided into p-type current mirror and N-type current mirror, namely corresponding to by
Two PMOS transistors are constituted and are made up of two nmos pass transistors.
Preferably, the first transistor NM1 and second transistor NM2 in the present embodiment are nmos pass transistor, described
Third transistor PM1 and the 4th transistor PM2, the third transistor PM1 and the 4th crystal can be included in first current mirror
Pipe PM2 is PMOS transistor.Wherein, the source electrode of the third transistor PM1 and the 4th transistor PM2 can access the switch
The input voltage VIN of power supply 200, the source electrode of the first transistor NM1 can be grounded.
It should be noted that first current mirror and the second current mirror are not limited to such scheme, for example, described
One transistor and second transistor can be PMOS transistor, and the third transistor and the 4th transistor can be NMOS crystal
Pipe.
It should also be noted that, how the embodiment of the present invention obtains institute according to the second reference current Ir2 if not being limited
State the 3rd reference current Ir3.
Preferably, second current branch can also include the 3rd current mirror (not indicated in figure), the 3rd electric current
Mirror is suitable to carry out mirror image to the second reference current Ir2, to obtain the 3rd reference current Ir3, and via its output end
(namely drain electrode of the 5th transistor PM3 in figure) is exported.Preferably, in the present embodiment, the 3rd current mirror can be with
First current mirror shares the third transistor PM3.
In a change case, the 3rd reference current Ir3 can be equal to the second reference current Ir2.
Alternatively, the 3rd reference current Ir3 is equal to the first reference current Ir1, the first transistor NM1's
The ratio of breadth length ratio and the breadth length ratio of the second transistor NM2 is more than 1.
It should be noted that the breadth length ratio referred in the embodiment of the present invention is equivalent breadth length ratio.For example, the first crystal
The ratio of pipe NM1 breadth length ratio and the breadth length ratio of the second transistor NM2 is more than 1, and 1 breadth length ratio can be more than using quantity
Equal NMOS tube is in parallel, and the breadth length ratio of the NMOS tube is equal with the breadth length ratio of the second transistor NM2.
Preferably, in specific implementation, the detection module 20 can also include potential-divider network (not indicated in figure), and it the
One input couples the switching node SW, its second input coupling reference edge, its partial pressure output end output association electricity
Press SWT.The reference edge can be ground, namely the port that voltage is zero, but not limited to this, the reference edge can also for ground with
Outer port.The potential-divider network can include first resistor R1 and second resistance R2.The resistance and two of the first resistor R1
The ratio of person's resistance is the intrinsic standoff ratio of the potential-divider network.The circuit knot being known to the skilled person due to the potential-divider network
Structure, to put it more simply, no longer expansion description one by one herein.
In embodiments of the present invention, the logic module 30 can include d type flip flop 301.Its reset terminal R couples the master
M1 control end is switched, namely accesses the control signal PWM, alternatively, the control signal PWM can be via buffer B2
Access the reset terminal R；Its data input pin D accesses the first control voltage V1；Its data output end Q couples the first switch
S1 control end, its clock end CLK couples the output end of the detection module 20, it is preferable that the testing result Vcmp via
Buffer B1 accesses the clock end CLK.
Wherein, in the controlled conductings of the main switch M1, the d type flip flop 301 resets, to cause the first switch S1
Controlled shutdown；Indicate that the association voltage SWT is less than in the main switch M1 controlled shutdowns and the testing result Vcmp described
During threshold voltage, the data output end Q of the d type flip flop 301 exports the first control voltage V1, to cause described first to open
The controlled conductings of S1 are closed until the controlled conductings of the main switch M1.In specific implementation, the d type flip flop 301 can be rising edge
Triggering can also be trailing edge triggering, can carry out the regulation of electrical circuit according to the logic level of the testing result Vcmp.
When the first switch S1 is suitable to the controlled conducting when its control end is high level, it is preferable that first control
Voltage V1 processed is the input voltage VIN of the Switching Power Supply 200, and the input voltage VIN can be identified as logic high.
It is understood to one skilled in the art that the logic realization in digital circuit can have various configurations scheme, Ke Yigen
Configured according to the truth table of input and output, therefore, the logic module 30 can be used beyond the d type flip flop 301
Other logic modules are realized.
Fig. 4 shows the working waveform figure of the Switching Power Supply 200.
In the lump referring to Fig. 3 and Fig. 4, the voltage of the control end of the low tension switch S1 is represented with Q, and divided with " 1 " and " 0 "
Biao Shi not logic high and logic low.Assuming that the first switch M1 is turned in logic high, the d type flip flop
301 are triggered by trailing edge, and are resetted in logic high.
The control signal PWM is periodic signal, and its cycle is T, namely the switch periods of the Switching Power Supply 200 are T.
T is made up of T1 and T2, wherein, T1 corresponds to PWM=" 1 ", and the switching tube M1 conductings, T2 is described to open corresponding to PWM=" 0 "
Close pipe M1 shut-offs.
It is that in T, during PWM=" 1 ", the d type flip flop 301 resets so that Q=" 0 ", described first in switch periods
Switch S1 shut-offs；At PWM=" 0 ", the d type flip flop 301 departs from reset state, because the voltage of the switching node SW is
" 1 ", therefore, the association voltage are " 1 ", and the source electrode of the second transistor NM2 is positive voltage, first reference current
Ir1 compares electric current Ic, Vcmp=" 1 " more than or equal to described, and the d type flip flop 301 is not updated the data to its data output end, because
This, the first switch S1 shut-offs；At the 1. moment, because the inductance L1 electric energy stored discharges completely, namely occurs ring
Phenomenon, the association voltage SWT declines rapidly, when its deteriorate to less than zero it is even lower when so that first reference current
Ir1 is changed into " 0 " less than the electric current Ic, Vcmp of comparing from " 1 ", and the d type flip flop 301 updates number in the presence of the trailing edge
According to entering, and Q is set to " 1 ", the first switch S1 conductings, the electric charge of the inductance L1 storages passes through ring and suppresses resistance Ring
Quickly release, so as to avoid LC vibrations；At the 2. moment, PWM is changed into " 1 ", and Q is set to " 0 ", the first switch S1 shut-offs,
So that the Switching Power Supply 200 works again and again.
It should be noted that " logic high " herein refers to that the level model of data signal " 1 " can be identified as
Enclose, " logic low " refers to that the level range of data signal " 0 " can be identified as, and the two is relative concept, and its is specific
Level range is simultaneously not particularly limited.
Although present disclosure is as above, the present invention is not limited to this.Any those skilled in the art, are not departing from this
In the spirit and scope of invention, it can make various changes or modifications, therefore protection scope of the present invention should be with claim institute
The scope of restriction is defined.
Claims (10)
1. a kind of Switching Power Supply, including inductance, main switch, the controlled on or off of main switch, so that the Switching Power Supply
Output end output have output voltage, it is characterised in that also include：
With the tie point of the inductance in parallel, the tie point includes the first switch of series connection and ring suppresses resistance, institute
The connecting node for stating inductance and main switch is designated as switching node；
Detection module, is adapted to detect for whether association voltage is less than threshold voltage, its output end output testing result, the association electricity
Pressure is associated with the voltage of the switching node；
Logic module, its first input end couples the output end of the detection module, and its second input couples the main switch
Control end, when the main switch controlled shutdown and the testing result indicate that the association voltage is less than the threshold voltage
When, the logic module controls the first switch conducting up to the controlled conducting of the main switch, otherwise, the logic module control
Make the first switch shut-off.
2. Switching Power Supply according to claim 1, it is characterised in that the threshold voltage is less than 0V.
3. Switching Power Supply according to claim 1, it is characterised in that the detection module includes：
First current branch, is exported suitable for producing default first reference current, and via its output end；
Second current branch, compares electric current, and export via its output end suitable for being produced according to association voltage；
Wherein, first reference current be more than or equal to it is described compare electric current when, the testing result be the first logic level,
With indicate it is described association voltage be more than or equal to the threshold voltage, first reference current be less than it is described compare electric current when,
The testing result is the second logic level different from first logic level, to indicate that it is described that the association voltage is less than
Threshold voltage.
4. Switching Power Supply according to claim 3, it is characterised in that first current branch includes：First current mirror,
Suitable for carrying out mirror image to the second reference current, to obtain the first reference current；
Second current branch includes：Second current mirror, suitable for according to the 3rd reference current mirror image obtain it is described compare electric current,
The current value of 3rd reference current is equal to the current value of second reference current, and it is brilliant that second current mirror includes first
Body pipe and second transistor, the first transistor access the 3rd reference current, and the output end of the second transistor is defeated
Go out it is described compare electric current, the input of the second transistor accesses the association voltage；
Wherein, the ratio of second reference current and first reference current be less than the breadth length ratio of the first transistor with
The ratio of the breadth length ratio of the second transistor.
5. Switching Power Supply according to claim 4, it is characterised in that the first transistor and second transistor are NMOS
Transistor, first current mirror includes third transistor and the 4th transistor, and the third transistor is with the 4th transistor
PMOS transistor.
6. Switching Power Supply according to claim 4, it is characterised in that second current branch also includes：3rd electric current
Mirror, suitable for carrying out mirror image to second reference current, to obtain the 3rd reference current, and is exported via its output end.
7. Switching Power Supply according to claim 6, it is characterised in that the 3rd reference current is equal to the described first reference
Electric current.
8. the Switching Power Supply according to any one of claim 3 to 7, it is characterised in that the detection module also includes：Point
Pressure network network, its first input end couples the switching node, its second input coupling reference edge, its partial pressure output end output institute
State association voltage.
9. Switching Power Supply according to any one of claim 1 to 7, it is characterised in that the logic module includes：
D type flip flop, its reset terminal couples the control end of the main switch, and its data input pin accesses the first control voltage, and it is counted
The control end of the first switch is coupled according to output end, its clock end couples the output end of the detection module；
Wherein, in the controlled conducting of the main switch, the d type flip flop resets, to cause the first switch controlled shutdown；
When the main switch controlled shutdown and the testing result indicate that the association voltage is less than the threshold voltage, the D triggerings
The data output end of device exports first control voltage, to cause the controlled conducting of the first switch until the main switch by
Conduct is led to.
10. Switching Power Supply according to claim 9, it is characterised in that it is height that the first switch, which is suitable in its control end,
Controlled conducting during level, first control voltage is the input voltage of the Switching Power Supply.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710497391.6A CN107302306B (en) | 2017-06-26 | 2017-06-26 | A kind of Switching Power Supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710497391.6A CN107302306B (en) | 2017-06-26 | 2017-06-26 | A kind of Switching Power Supply |
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| CN107302306A true CN107302306A (en) | 2017-10-27 |
| CN107302306B CN107302306B (en) | 2019-05-24 |
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| CN112311227A (en) * | 2019-08-01 | 2021-02-02 | 圣邦微电子（北京）股份有限公司 | Switch power supply and ringing elimination circuit and ringing elimination method thereof |
| CN113541220A (en) * | 2020-04-21 | 2021-10-22 | 圣邦微电子（北京）股份有限公司 | Load detection circuit and charging system |
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| Publication number | Publication date |
|---|---|
| CN107302306B (en) | 2019-05-24 |
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Address after: 201199 Room 1201, Lane 908, Xiuwen Road, Minhang District, Shanghai Patentee after: SHANGHAI AWINIC ELECTRONIC TECHNOLOGY CO., LTD. Address before: Room 303-39, 33 Block 680 Guiping Road, Xuhui District, Shanghai, 2003 Patentee before: SHANGHAI AWINIC ELECTRONIC TECHNOLOGY CO., LTD. |