CN104283409B - Self-powered source electrode drive circuit and switch power source with self-powered source electrode drive circuit - Google Patents
Self-powered source electrode drive circuit and switch power source with self-powered source electrode drive circuit Download PDFInfo
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- CN104283409B CN104283409B CN201410535018.1A CN201410535018A CN104283409B CN 104283409 B CN104283409 B CN 104283409B CN 201410535018 A CN201410535018 A CN 201410535018A CN 104283409 B CN104283409 B CN 104283409B
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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
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
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Abstract
The invention discloses a self-powered source electrode drive circuit and a switch power source with the self-powered source electrode drive circuit. When a first transistor is connected, the source electrode voltage of a main power tube in a power-level circuit is reduced; when the grid source voltage of the main power tube reaches the conduction threshold voltage of the main power tube, the main power tube is connected; after the first transistor is disconnected, a delay circuit controls the main power tube to be disconnected after delay of a period of time so that a power-supplying capacitor can charge till the expected supply voltage of a control circuit is reached. By means of the technical scheme, it can be guaranteed that the power-supplying capacitor has enough charging time and charging energy, and the power-supplying requirement of a chip can be met under the situation that no capacitor is added.
Description
The application is to be 2012 month November 05 applying date, Application No. 201210435979.6, invention entitled " a kind of
The divisional application of self-powered source electrode drive circuit and the Switching Power Supply applying it ".
Technical field
The present invention relates to field of power supplies, more particularly, it relates to a kind of self-powered source electrode drive circuit and apply it
Switching Power Supply.
Background technology
Source pole driving mode is widely used in Switching Power Supply due to its low power consumption high efficiency, and its cardinal principle is by master
The grid voltage of power tube is fixed on certain numerical value, by changing its source voltage thus controlling the switch shape of main power tube
State.
As shown in figure 1, being a kind of circuit diagram of employing source drive in prior art, described source electrode drive circuit includes
One the first transistor, feedback stream diode and power supply capacitor, a power end of described the first transistor and the source of described main power tube
Pole connects, another power end ground connection；Described power supply capacitor one terminates the control end of described main power tube, and the other end is grounded；Described
The anode of feedback stream diode connects described main power tube and the points of common connection of described the first transistor, and its negative electrode connects described power supply electricity
Hold and the control end of described main power tube between.The ultimate principle of its source drive is: by described the first transistor qsOpen
Off status is controlling main power tube qmOn off state, as described the first transistor qsDuring conducting, described main power tube qmSource electrode
Voltage reduces, when its gate source voltage reaches its on state threshold voltage, main power tube qmConducting；As described the first transistor qsClose
When disconnected, described main power tube qmSource voltage raise, when its gate source voltage be less than on state threshold voltage when, main power tube qmClose
Disconnected.A control circuit is also included, it produces a pwm control signal to control described the first transistor q in described Switching Power Supplys's
On off state, described power supply capacitor chThere is provided supply voltage to described control circuit.As shown in fig. 1, as main power tube qmTurn off
Afterwards, the electric current in power stage circuit passes through main power tube qmDrain-source between parasitic capacitance cds, feedback stream diode d ' is to described power supply
Electric capacity chCharge.But this method is disadvantageous in that when input voltage is relatively low, the posting of the drain-source interpolar of main power tube
Raw electric capacity very little, often it is difficult to ensure that power supply capacitor chSufficiently large magnitude of voltage can be charged to, so that it cannot provide described
Supply voltage required for control circuit.Therefore, for ensure control circuit normal power supply, need main power tube drain-source it
Between an additional electric capacity, with the capacitance increasing parasitic capacitance to improve main power tube turn off when main circuit current to power supply capacitor ch
The energy charging, but this mode can increase switching loss.
Content of the invention
In view of this, the invention provides a kind of self-powered source electrode drive circuit, it is controlled by delay circuit
One transistor closes has no progeny, and described main power tube postpones to turn off for a period of time again, so can ensure that power supply capacitor has enough filling
Electric time and the chargeable supply voltage to required for control circuit of rechargeable energy.Solve due to the energy storage in power supply capacitor
Not make chip cannot normal work problem.
According to a kind of self-powered source electrode drive circuit of the present invention, it is applied in Switching Power Supply, described Switching Power Supply bag
Include a power stage circuit, described source electrode drive circuit includes a first transistor, feedback stream diode and power supply capacitor, described
Source electrode drive circuit also includes a delay circuit, and described the first transistor controls its on off state by a pwm control signal:
When described the first transistor turns on, the source voltage of the main power tube in described power stage circuit declines, when it
When gate source voltage reaches its on state threshold voltage, described main power tube conducting；
When described the first transistor turns off, described delay circuit controls described main power tube to be delayed to turn off, so that described
The power supply capacitor charging interval, its both end voltage can rise to a reference voltage level enough.
Further, described delay circuit includes one first Zener diode and the first diode, described first Zener two
The negative electrode of pole pipe is connected to the control end of described main power tube, its plus earth；
The negative electrode of described first diode is connected on the negative electrode of described first Zener diode and the control of described main power tube
The points of common connection at end, its anode is connected to described power supply capacitor and the points of common connection of described feedback stream diode.
Preferably, the breakdown voltage of described first Zener diode is described reference voltage level and the leading of described main power tube
Logical threshold voltage sum.
Further, described delay circuit also includes first switch pipe and first resistor, and described first resistor is serially connected in institute
State between the negative electrode of the first Zener diode and the control end of described main power tube；
The control end of first resistor and described main power tube described in first power terminations of described first switch pipe public
Junction point, its second power end is grounded, and it controls and terminates the commonly connected of described first resistor and described first Zener diode
Point；Wherein, described first switch pipe is p-type transistor.
Further, described delay circuit also includes second switch pipe, and the breakdown voltage of described first Zener diode is
Described reference voltage level, the anode of the first Zener diode described in the first power terminations of described second switch pipe, its second work(
Rate end is grounded, and any one moment before described the first transistor turns off for the described second switch pipe turns off, in described power supply electricity
Capacity charge to described control circuit expectation supply voltage when conducting.
Further, described delay circuit also includes the 3rd switching tube and second resistance, and described second resistance is serially connected in institute
State between the negative electrode of the first Zener diode and the control end of described main power tube；
The control end of second resistance and described main power tube described in first power terminations of described 3rd switching tube public
Junction point, its second power terminations is in the points of common connection of described power supply capacitor and described feedback stream diode；It controls termination institute
State second resistance and the points of common connection of described first Zener diode；Wherein, described 3rd switching tube is p-type transistor.
Further, described delay circuit includes the second diode and 3rd resistor, and the negative electrode of described second diode connects
The control end of described main power tube, its anode is connected on described power supply capacitor and the points of common connection of described feedback stream diode；Described
3rd resistor is connected with described second diodes in parallel.
According to a kind of Switching Power Supply of the present invention, including power stage circuit, control circuit and described source electrode drive circuit,
Described source electrode drive circuit receives the pwm control signal of described control circuit output with to the main power in described power stage circuit
Pipe is driven；Wherein, the power supply capacitor in described source electrode drive circuit provides supply voltage for described control circuit, and described
Power supply capacitor both end voltage charges to reference voltage level, and described reference voltage level is the expectation supply voltage of described control circuit.
Via above-mentioned technical scheme understand, according to embodiments of the invention self-powered source electrode drive circuit have with
Lower advantage, it passes through delay circuit so that having no progeny in the first transistor pass, and described main power tube postpones to turn off for a period of time again,
Can ensure that power supply capacitor has enough charging intervals and rechargeable energy, in the case of not needing to increase electric capacity, control can be met
The power reguirements of coremaking piece.
Brief description
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
Have technology description in required use accompanying drawing be briefly described it should be apparent that, drawings in the following description be only this
Inventive embodiment, for those of ordinary skill in the art, on the premise of not paying creative work, can also basis
The accompanying drawing providing obtains other accompanying drawings.
Fig. 1 show a kind of circuit diagram of employing source drive in prior art；
Fig. 2 show the circuit diagram of the first embodiment of a kind of self-powered source electrode drive circuit according to the present invention；
Fig. 3 show the circuit diagram of the second embodiment of a kind of self-powered source electrode drive circuit according to the present invention；
Fig. 4 a show the circuit diagram of the 3rd embodiment of a kind of self-powered source electrode drive circuit according to the present invention；
Fig. 4 b show the physical circuit figure of first control circuit shown in Fig. 4 a；
Fig. 4 c show the working waveform figure of circuit diagram shown in Fig. 4 a；
Fig. 5 show the circuit diagram of the fourth embodiment of a kind of self-powered source electrode drive circuit according to the present invention；
Fig. 6 show the circuit diagram of the 5th embodiment of a kind of self-powered source electrode drive circuit according to the present invention；
Fig. 7 show the circuit diagram of the sixth embodiment of a kind of self-powered source electrode drive circuit according to the present invention；
Specific embodiment
Below in conjunction with accompanying drawing, several preferred embodiments of the present invention are described in detail, but the present invention is not restricted to
These embodiments.The present invention covers any replacement made in the spirit and scope of the present invention, modification, equivalent method and side
Case.In order that the public has to the present invention thoroughly understanding, it is described in detail specifically thin in present invention below preferred embodiment
Section, and description without these details can also understand the present invention completely for a person skilled in the art.
With reference to Fig. 2, it show the circuit of the first embodiment of a kind of self-powered source electrode drive circuit according to the present invention
Figure, described source electrode drive circuit is applied in a Switching Power Supply, includes a power stage circuit and control in described Switching Power Supply
Circuit, power stage circuit is buck topology structure as shown in Figure 2, includes a main power tube in described power stage circuit
qm, the pwm control signal of the described source electrode drive circuit described control circuit output of reception is with to described main power tube qmDriven
Dynamic.Wherein, include a first transistor q in described source electrode drive circuits, feedback stream diode d ' and power supply capacitor ch, wherein,
Described pwm control signal is in order to control described the first transistor qsOn off state, described power supply capacitor chFor described control circuit
Supply voltage is provided.Further, described source electrode drive circuit also includes a delay circuit, and described delay circuit is in order to control
Described the first transistor qsHaving no progeny in pass, controls described main power tube qmPostpone to turn off again, to ensure described power supply capacitor for a period of time
Charging interval enough, allows it to charge to a reference voltage level, here, described reference voltage level is described control circuit
Expect supply voltage.A kind of specific implementation with reference to the delay circuit shown in Fig. 2 illustrates source described in the present embodiment
The work process of pole drive circuit.
As shown in Fig. 2 described delay circuit includes one first Zener diode dz1With the first diode d1, described first is neat
Receive diode dz1Negative electrode be connected to described main power tube qmControl end, its plus earth；The moon of described first diode d1
Pole is connected on the negative electrode of described first Zener diode and the points of common connection of the control end of described main power tube, and its anode is connected to
Described power supply capacitor chWith the points of common connection of described feedback stream diode d ', wherein, described first Zener diode dz1Puncture
Voltage is the on state threshold voltage sum with described main power tube for the expectation supply voltage of described control circuit.
The work process of the source electrode drive circuit of the present embodiment is described below according to the circuit diagram shown in Fig. 2, according to Fig. 2,
Before described the first transistor qs turns on, described power supply capacitor chConnect the grid of described main power tube by the first diode d1
Pole, thus its grid voltage is approximately vcc.When described control circuit controls described the first transistor qsDuring conducting, described main power
Pipe qmSource voltage decline, when described main power tube gate source voltage be more than its on state threshold voltage, described main power tube qmLead
Logical, described input voltage vin charges to inductance l.Afterwards, when described pwm control signal controls described the first transistor qsTurn off,
Described main power tube qmSource voltage begin to ramp up, now, due to described first Zener diode dz1Do not have breakdown, because
This, parasitic capacitance c between the grid source of described main power tubegsDischarge loop can not be produced, the gate source voltage of described main power tube is big
In its on state threshold voltage, described main power tube remains on, and described inductive current passes through main power tube qm, feedback stream diode
D ' is to described power supply capacitor chContinue to charge.Source voltage with main power tube is gradually increasing, and its grid voltage is also gradually gone up
Rise, when the grid voltage of described main power tube reaches described first Zener diode dz1Breakdown voltage when, described first Zener
Diode dz1Breakdown, between the grid source of described main power tube parasitic capacitance cgsBy described first Zener diode dz1Formed
Discharge loop, the grid voltage of described main power tube starts to reduce, and the gate source voltage of described main power tube is also gradually reduced, and works as institute
When stating the gate source voltage of main power tube and decreasing below its on state threshold voltage, described main power tube qmTurn off.Wherein, described
One diode d1 is in order to prevent parasitic capacitance c between the grid source of described main power tubegsBy described power supply capacitor chElectric discharge.
From above-mentioned work process can be seen that the delay circuit of the present embodiment by the setting of the first Zener diode Lai
Controlling makes main power tube close in the first transistor to have no progeny and do not turn off immediately, and is to continue with being held on a period of time so that power supply
Electric capacity continues to charge, and it can be made to be charged to the supply voltage required for control circuit, compared with prior art, the present invention does not need
It is ensured that power supply capacitor can the fully charged energy enough with storage in the case of an additional electric capacity between the drain-source of main power tube
Meet the demand of control circuit.
With reference to Fig. 3, it show the circuit of the second embodiment of a kind of self-powered source electrode drive circuit according to the present invention
Figure；On the basis of embodiment one, described delay circuit further includes first switch pipe q1 and first resistor r1 to the present embodiment,
Described first resistor r1 is serially connected in described first Zener diode dz1Negative electrode and described main power tube qmControl end between；Institute
State the first resistor described in the first power terminations of first switch pipe q1 and described main power tube qmControl end points of common connection,
Its second power end is grounded, and it controls described first resistor r1 of termination and described first Zener diode dz1Points of common connection.
In the present embodiment, described first Zener diode dz1Breakdown voltage be described reference voltage level and described main power tube conducting
Threshold voltage sum, is the on state threshold voltage sum with described main power tube for the expectation supply voltage of described control circuit.
It should be noted that described first switch pipe is p-type transistor, for example, can be p-type bipolar transistor or p-type field effect crystalline substance
Body pipe, illustrates in the present embodiment taking p-type field-effect transistor as a example.
Delay circuit shown in the present embodiment is essentially identical with the operation principle of embodiment one, and it mainly passes through described the
Zener diode dz1Make main power tube q to controlmIn described the first transistor qsHave no progeny and postpone to turn off again for a period of time in pass, with
Make power supply capacitor chObtain enough charging intervals.In described first Zener diode dz1Before breakdown, described delay circuit
Work process identical with embodiment one, here do not repeat illustrate, except that, in described first Zener diode dz1Hit
After wearing, described main power tube qmGrid source between parasitic capacitance cgsBy described first resistor r1 and described first Zener diode
dz1Form discharge loop, due to there being electric current to pass through in first resistor r1, between the source grid of described first switch pipe q1, form pressure reduction, when
When between the source grid of described first switch pipe q1, pressure reduction reaches its on state threshold voltage, described first switch pipe q1 conducting, at this moment, institute
State parasitic capacitance c between the grid source of main power tubegsDischarged by described first switch pipe q1.Described main power tube qmGrid source electricity
Pressure is gradually reduced, as described main power tube qmGate source voltage when decreasing below its on state threshold voltage, described main power tube qm
Turn off.
Therefore, compared with embodiment one, the present embodiment is equally achieved to be controlled by described first Zener diode and makes
Main power tube postpones to turn off for a period of time so that power supply capacitor continues to charge in the first transistor again；Additionally, the present embodiment passes through
First switch pipe directly discharges over the ground, it is to avoid first Zener diode bears high current.
With reference to Fig. 4 a, it show the circuit of the 3rd embodiment of a kind of self-powered source electrode drive circuit according to the present invention
Figure；The source electrode drive circuit of the present embodiment is similarly applied in the Switching Power Supply that power stage circuit is buck topology structure,
The delay circuit of the present embodiment further includes second switch pipe q2 on the basis of embodiment one, first described in the present embodiment
Breakdown voltage d of Zener diodez1For described reference voltage level, that is to say the expectation supply voltage of described control circuit, described
First Zener diode d described in first power terminations of second switch pipe q2z1Anode, its second power end is grounded, described the
Two switching tube q2 any one moment before described the first transistor qs turns off turns off, and it is in described power supply capacitor chCharge to institute
Turn on during the expectation supply voltage stating control circuit.
Preferably, described second switch pipe q2 is controlled to turn off in described the first transistor qs turn-on instant in the present embodiment,
According to the control program of the present embodiment, the present embodiment specifically describes the first of the switch motion controlling described second switch pipe q2
Control circuit 401, show the physical circuit figure of first control circuit shown in Fig. 4 a with reference to Fig. 4 b.Described first control circuit
Including the first one-shot circuit 4011, first comparator 4012, the second one-shot circuit 4013 and triggers circuit 4014.Described
One one-shot circuit 4011 receives described pwm control signal, produces the first pulse after processing through the first one-shot circuit 4011
Signal transmission gives described triggers circuit 4014；Two inputs of described first comparator 4012 receive described power supply capacitor respectively
Both end voltage vccWith a reference voltage level vref, export a comparison signal after being compared, described comparison signal is through described second
One-shot circuit 4013 forms the second single pulse signal and is transferred to described triggers circuit after being processed；Wherein, described reference electricity
Pressure value vrefIt is set to the expectation supply voltage of described control circuit；Described triggers circuit 4014 is specially a rs trigger, and it connects
Receive described first single pulse signal as reset signal, receive described second single pulse signal as set signal, and produce institute
State the first control signal v1 to control the switch motion of described second switch pipe q2.It should be noted that described first controls electricity
Road 401 is a kind of specific implementation controlling described second switch pipe q2, skilled person will appreciate that, described second switch
The control of the switch motion of pipe q2 can also have the circuit equivalent of identical function by other.
It show the source drive electricity to the present embodiment for the working waveform figure of circuit diagram shown in Fig. 4 a with reference to Fig. 4 c
The work process on road is further elaborated: in the t0 moment, described pwm control signal is changed into high level state and controls described the
One transistor qs conducting, described main power tube qmSource voltage vs be pulled low, when the gate source voltage of described main power tube is more than
Its on state threshold voltage, described main power tube qmConducting, described input voltage vin charges to inductance l.Meanwhile, described
One control circuit receives after described pwm control signal is processed through the first one-shot circuit and forms the first single pulse signal, and passes through
Described triggers circuit controls described second switch pipe q2 to turn off.In the t1 moment, when described pwm control signal is changed into low level control
Described the first transistor qs turns off, and now the source voltage vs of described main power tube is increased to the both end voltage of described power supply capacitor
vcc.During t0 to t1, described power supply capacitor due to powering power consumption to control circuit, its both end voltage vccCan slightly decline,
As voltage v in Fig. 4 cccShown, therefore, in t1 moment, both end voltage v of described power supply capacitorccLess than described reference voltage level
vref, described first control circuit still controls makes described second switch pipe q2 be held off, so, the grid of described main power tube
Parasitic capacitance c between sourcegsDischarge loop can not be produced, and because the source voltage vs of described main power tube is upgraded to vcc, thus grid
Pole tension vg is upgraded to 2vcc, described main power tube remains on state.Because main power tube is held on, described inductive current
By main power tube qm, feedback stream diode d ' continues to charge to described power supply capacitor, until described both end voltage vccReach reference
Magnitude of voltage vref, in t1 to the t2 time in such as Fig. 4 c, when power supply capacitor both end voltage vccReach described reference voltage level vrefWhen, institute
The comparison signal stating first comparator output is changed into high level, controls described second switch pipe q2 to lead by described triggers circuit
Logical, because the grid voltage of described main power tube is higher than described first Zener diode dz1Breakdown voltage, described first Zener
Diode dz1Breakdown, between the grid source of described main power tube parasitic capacitance cgsBy the first Zener diode dz1With described
Two switching tube q2 electric discharges, when it is discharged to the gate-source voltage of described main power tube and is less than its on state threshold voltage, described master
Power tube qmTurn off.Until next cycle, in the t3 moment, described pwm control signal is changed into high level state and controls described first
Transistor qs turns on, and described source electrode drive circuit is according to said process circulation work.
From said process as can be seen that the described delay circuit of the present embodiment, it is by the delay of described second switch pipe
Conducting is so that in described the first transistor qsHave no progeny in pass, described main power tube qmDo not turn off immediately, and be to continue with holding and lead
Logical a period of time, to maintain power supply capacitor to continue to charge, is charged to the supply voltage required for control circuit up to it.
With reference to Fig. 5, it show the circuit of the fourth embodiment of a kind of self-powered source electrode drive circuit according to the present invention
Figure；Delay circuit in the present embodiment includes the first Zener diode dz1, second switch pipe q2 and first control circuit 501, with
Embodiment three connection all same, here not repeated description, except that, in the present embodiment, delay circuit also includes the 3rd switch
Pipe q3 and second resistance r2, described second resistance r2 is serially connected in described main power tube qmControl end and described first Zener two pole
Pipe dz1Negative electrode between；Second resistance r2 described in first power terminations of described 3rd switching tube q3 and described main power tube qm's
The points of common connection of control end, its second power terminations is in described power supply capacitor chFlow the commonly connected of diode d ' with described feedback
Point, it controls described second resistance r2 of termination and described first Zener diode dz1Points of common connection, wherein, the described 3rd opens
Closing pipe is p-type transistor, illustrates in the present embodiment taking p-type field-effect transistor as a example.Here, described 3rd switching tube
Parasitic diode d2-1 is same with the first diode d1 function phase in embodiment three, can equivalent substitute.
Work process below against the source electrode drive circuit to the present embodiment for the physical circuit figure shown in Fig. 5 is made further
Illustrate: the principle same with embodiment three, described delay circuit passes through to control the turn on delay of second switch pipe q2 to control institute
State main power tube and close to have no progeny in described the first transistor and postpone to turn off again for a period of time, so that described power supply capacitor chDuring charging
Between and rechargeable energy enough to reach the supply voltage of described control circuit, its identical work process here is not repeated.Institute
Except for the difference that, when described power supply capacitor chCharging reaches reference voltage level vref, described first control circuit 501 controls second to open
Close pipe q2 conducting, parasitic capacitance c between the grid source of described main power tubegsBy described second resistance r2, the first Zener diode
Dz1 and described second switch pipe q2 forms discharge loop, because second resistance r2 has electric current to pass through, described 3rd switching tube q3's
There is pressure reduction in source grid, when its source grid voltage difference reaches its on state threshold voltage, described 3rd switching tube q3 conducting, this
When, described main power tube qmGrid source between parasitic capacitance cgsMainly pass through the 3rd switching tube q3, power supply capacitor chElectric discharge, until
When the gate-source voltage of described main power tube is less than its on state threshold voltage, described main power tube qmTurn off.
The delay circuit of the present embodiment is again by controlling in the first transistor qsHave no progeny described main power tube of pass postpones
A period of time turns off to ensure that power supply capacitor charges fully again, and will not produce electricity shortage makes the control circuit cannot normal work
Situation.In the present embodiment, parasitic capacitance c between the grid source of described main power tubegsBy the 3rd switching tube q2, power supply capacitor ch
On the one hand carry out electric discharge can avoid the first Zener diode to flow through high current, on the other hand can be by parasitic capacitance cgsDischarge into
Power supply capacitor chIn, increased the electricity of power supply.
With reference to Fig. 6, it show the circuit of the 5th embodiment of a kind of self-powered source electrode drive circuit according to the present invention
Figure；The present embodiment is that embodiment two and embodiment three combine to be optimized configuration, to reach best-of-breed technology effect, such as schemes
Shown in 6, described delay circuit includes the first Zener diode dz1, second switch pipe q2, the first diode d1 and first control electricity
Road 601, foregoing circuit and embodiment three connect identical, additionally, the present embodiment also includes the first switch pipe q1 in embodiment two
With first resistor r1, its connection is identical with embodiment two, does not all repeat to illustrate.
With embodiment three in the same manner, the described delay circuit in the present embodiment passes through to control the turn on delay of second switch pipe q2
Turned off again for a period of time with controlling described main power tube to close, in described the first transistor, delay of having no progeny, so that described power supply capacitor
ch, enough to reach the supply voltage of described control circuit, its identical work process here is no longer for charging interval and rechargeable energy
Repeat.Except that, parasitic capacitance c after described second switch pipe q2 conducting, between the grid source of described main power tubegsPass through
Described first resistor r1, the first Zener diode dz1Form discharge loop with described second switch pipe q2, due to first resistor r1
Electric current is had to pass through, the source grid of described first switch pipe q1 has pressure reduction, when its source grid voltage difference reaches its conduction threshold electricity
During pressure, described first switch pipe q1 conducting, at this moment, parasitic capacitance c between the grid source of described main power tubegsBy first switch pipe
Q1 discharges, until when the gate-source voltage of described main power tube is less than its on state threshold voltage, described main power tube qmTurn off.
It can be seen that, distributing rationally by the present embodiment, the present embodiment delay circuit passes through the main power of second switch management and control system
Pipe postpones a period of time shutoff, to meet the charging requirement of power supply capacitor, and parasitic capacitance c between the grid source of main power tubegsCan
Directly discharged by first switch pipe q1, the first Zener diode can be avoided to flow through high current.
With reference to Fig. 7, it show the circuit of the sixth embodiment of a kind of self-powered source electrode drive circuit according to the present invention
Figure；Delay circuit described in the present embodiment includes the second diode d2 and 3rd resistor r3, the negative electrode of described second diode d2
Meet described main power tube qmControl end, its anode is connected on described power supply capacitor chFlow the commonly connected of diode d ' with described feedback
Point；Described 3rd resistor r3 is connected in parallel with described second diode d2.
Illustrate the work process of the source electrode drive circuit of the present embodiment below against Fig. 7: when described pwm control signal controls
Described the first transistor qsConducting, described main power tube qmSource voltage decline, and its grid voltage be vcc, when described main work(
The gate source voltage of rate pipe is more than its on state threshold voltage, described main power tube qmConducting.Afterwards, when described pwm control signal control
Make described the first transistor qsTurn off, the source voltage of described main power tube begins to ramp up, now, the grid source of described main power tube
Between parasitic capacitance cgsDischarged by 3rd resistor r3, but because the parasitic capacitance between 3rd resistor and grid source constitutes a deferred telegram
Road, can postpone parasitic capacitance c between the grid source of described main power tubegsDischarge rate, so, the grid voltage of main power tube declines
Ground is relatively slow, and main power tube can't immediately turn off, until the parasitic capacitance discharge between its grid source is to the grid source of described main power tube
When voltage is less than its on state threshold voltage, described main power tube turns off.
From said process as can be seen that the delay circuit of the present embodiment can arrange the 3rd according to the charging interval of power supply capacitor
The size of resistance, can be charged to voltage value required for control circuit, the present embodiment control program to realize power supply capacitor
Simply, low cost.
In sum, controlling according to source electrode drive circuit disclosed in this invention makes main power tube turn in the first transistor
When conducting, and the first transistor turn off a period of time after turn off again so that power supply capacitor can fully charged so that control can be met
The requirement that circuit is powered.The source electrode drive circuit of the present invention need not increase extra electric capacity, solves control circuit electricity shortage
Problem.
Finally, present invention also offers a kind of Switching Power Supply, drive including power stage circuit, control circuit and above-mentioned source electrode
Galvanic electricity road, described source electrode drive circuit receives the pwm control signal of described control circuit output with described power stage circuit
Main power tube be driven；Wherein, the power supply capacitor in described source electrode drive circuit provides power supply electricity for described control circuit
Pressure, and described power supply capacitor both end voltage charges to a reference voltage level, described reference voltage level is the phase of described control circuit
Hope supply voltage.
It should be noted that the source electrode drive circuit that the present invention provides disclosure satisfy that the power reguirements to control circuit, and
And the beneficial effect such as control circuit is simple, efficiency is high, accordingly, a kind of Switching Power Supply that the present invention provides equally has above-mentioned effect
Really.
Above detailed description is carried out to the delay circuit of the preferred embodiment in the source electrode drive circuit according to the present invention,
Those of ordinary skill in the art can deduce that other technologies or structure and circuit layout, element etc. all can be applicable to institute accordingly
State embodiment.
According to embodiments of the invention as described above, these embodiments do not have all of details of detailed descriptionthe, not yet
Limit the specific embodiment that this invention is only described.Obviously, as described above, can make many modifications and variations.This explanation
Book is chosen and is specifically described these embodiments, is to preferably explain the principle of the present invention and practical application, so that affiliated
Technical field technical staff can utilize the present invention and modification on the basis of the present invention to use well.The present invention is only subject to right
Claim and its restriction of four corner and equivalent.
Claims (3)
1. a kind of self-powered source electrode drive circuit, is applied in Switching Power Supply, and described Switching Power Supply includes a power stage electricity
Road, described source electrode drive circuit includes a first transistor, feedback stream diode and power supply capacitor it is characterised in that described source
Pole drive circuit also includes a delay circuit,
Described the first transistor controls its on off state by a pwm control signal:
When described the first transistor turns on, the source voltage of the main power tube in described power stage circuit declines, when its grid source
When voltage reaches its on state threshold voltage, described main power tube conducting；
Described delay circuit includes the 3rd resistor being connected between the grid of described main power tube and described power supply capacitor；
When described the first transistor turns off, described delay circuit controls described main power tube to be delayed to turn off, and arranges the described 3rd
The size of resistance is changing the charging interval of described power supply capacitor, so that the described power supply capacitor charging interval is enough, its two ends electricity
Pressure energy enough rises to a reference voltage level.
2. source electrode drive circuit according to claim 1 is it is characterised in that described delay circuit also includes the two or two pole
Pipe, the negative electrode of described second diode connects the control end of described main power tube, and its anode is connected on described power supply capacitor and described feedback
The points of common connection of stream diode.
3. a kind of Switching Power Supply is it is characterised in that include described in power stage circuit, control circuit and any one of claim 1-2
Source electrode drive circuit,
Described source electrode drive circuit receives the pwm control signal of described control circuit output with to the master in described power stage circuit
Power tube is driven；
Wherein, the power supply capacitor in described source electrode drive circuit provides supply voltage for described control circuit, and described power supply electricity
Hold both end voltage and charge to a reference voltage level, described reference voltage level is the expectation supply voltage of described control circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410535018.1A CN104283409B (en) | 2012-11-05 | 2012-11-05 | Self-powered source electrode drive circuit and switch power source with self-powered source electrode drive circuit |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210435979.6A CN102969889B (en) | 2012-11-05 | 2012-11-05 | A kind of self-powered source electrode drive circuit and apply its Switching Power Supply |
| CN201410535018.1A CN104283409B (en) | 2012-11-05 | 2012-11-05 | Self-powered source electrode drive circuit and switch power source with self-powered source electrode drive circuit |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210435979.6A Division CN102969889B (en) | 2012-11-05 | 2012-11-05 | A kind of self-powered source electrode drive circuit and apply its Switching Power Supply |
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| Publication Number | Publication Date |
|---|---|
| CN104283409A CN104283409A (en) | 2015-01-14 |
| CN104283409B true CN104283409B (en) | 2017-01-25 |
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| CN201410535018.1A Active CN104283409B (en) | 2012-11-05 | 2012-11-05 | Self-powered source electrode drive circuit and switch power source with self-powered source electrode drive circuit |
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| CN112803794A (en) * | 2021-02-25 | 2021-05-14 | Oppo广东移动通信有限公司 | Power adapter, power supply system and power supply method |
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Address after: 310051 No. 6 Lianhui Street, Xixing Street, Binjiang District, Hangzhou City, Zhejiang Province Patentee after: Silergy Semiconductor Technology (Hangzhou ) Co., Ltd. Address before: 310012 Xihu District, Hangzhou, Wensanlu Road, No. 90, East Software Park, science and technology building, A1501 Patentee before: Silergy Semiconductor Technology (Hangzhou ) Co., Ltd. |