CN209016930U - A kind of start-up circuit - Google Patents
A kind of start-up circuit Download PDFInfo
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- CN209016930U CN209016930U CN201821842482.5U CN201821842482U CN209016930U CN 209016930 U CN209016930 U CN 209016930U CN 201821842482 U CN201821842482 U CN 201821842482U CN 209016930 U CN209016930 U CN 209016930U
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Abstract
The utility model provides the start-up circuit of a kind of achievable ultra-wide AC or D/C voltage input range, and start-up circuit has and opens and shuts off controllable function.The start-up circuit can realize that low-voltage, high-current starting has the characteristics that high current, big return difference wherein second bootrom IC2 provides control starting and turn-off function there are many embodiment by electric resistance partial pressure.In addition it can also realize that low-voltage, high-current starts by way of zener diode clamper, peripheral circuits reduce PCB cloth plate suqare and volume, reduce cost, and do not limited by technique, can meet the needs of high density small size low cost power-supply system.
Description
Technical field
The utility model relates to Switching Power Supply, in particular to a kind of start-up circuit of switching power converters.
Background technique
In general, Switching Power Supply (hereinafter referred to as " power supply ") circuit all can include start-up circuit, so as in power supply electrifying
Shi Qidong controller, driving transformer convert voltage, realize the normal work of power supply, the power supply of controller at this time can by assist around
Group provides.
The start-up circuit part of major part controller uses traditional linear voltage-stabilizing circuit at present, as shown in Figure 1, for tradition
The simplification figure of linear start-up circuit, including resistance R1 and R2, capacitor C, zener diode Dz and triode T (or metal-oxide-semiconductor).One
The input voltage of a power supply generates an electric current by resistance R1, is input to the base terminal of triode, and driving triode saturation is led
It is logical, it generates electric current and gives start-up capacitance CVDDIt charges to complete the starting of controller.Start-up circuit shown in FIG. 1 is without any control
System, therefore the start-up circuit can continue consumption energy during power initiation on resistance R.In addition, being opened when output pulsation
Circuit is moved by repeated priming, causes to be lost.
As it can be seen that the start-up circuit haves the shortcomings that more, including the relatively lossy on resistance R, peripheral component is more, PCB
Fabric swatch is difficult, and volume is big, and purchase cost and production cost are all very high, is unfavorable for setting for high power density small footprint modular power supply
Meter, and starting voltage periphery are controlled without sluggishness, are be easy to cause start-up circuit to open repeatedly, are led to higher loss.Therefore it saves
The more effective scheme of power consumption for saving start-up circuit should (mean the controllable electricity for turning off and opening using controllable initiating circuit
Road) complete the starting of controller.
In order to solve the above problem, disclosed on October 7th, 2016 in the Chinese patent of Publication No. CN105529914A
Propose a kind of integrated controllable initiating circuit, basic schematic diagram such as Fig. 2.
Under high input voltage, it is shunt capacitance charging by lower bound starting current and high limit starting current, works as output voltage
VOUTAfter foundation, high-voltage starting circuit is closed, and can give VDD pin powered by auxiliary winding Ns2 at this time.Controller shown in Fig. 2
Other pin connection relationships and function it is unrelated with the utility model, do not show that.
To sum up, although appeal patent solves the defect of conventional linear voltage-stablizer, but its application range is still limited.
On the one hand, in the case where ultralow pressure direct current inputs application, there are problems that normally starting；On the other hand, which opens
Streaming current is not big enough, according to capacitor charge and discharge formula:
Wherein CVDDFor the shunt capacitance of controller VDD pin, IchargeFor start-up circuit charging current.
It knows when controller power consumption requirements are higher, then gives capacitance charging current to reduce, such as Multistage Control condition
Under, the starting time will lengthen significantly, and the system application high for starting time requirement will be no longer applicable in, and due to the great Rong of output
Property load requirement, the shunt capacitance C of VDD institute bandVDDIt can not be made small, therefore starting the time can not be by reducing shunt capacitance
Shorten, to will lead to higher application cost and occupy biggish pcb board volume.
Utility model content
In view of the limited of the prior art, the technical problem to be solved by the present invention is to provide a kind of start-up circuits, so that
Meet the starting of super wide range AC or DC input voltage, and big charging current is provided, peripheral circuits reduce PCB cloth plate face
Long-pending and volume, reduces cost, to meet the needs of high density small size low cost power-supply system.
In view of the above technical problems, the utility model discloses a kind of start-up circuit, for opening in voltage input at super wide range
Big charging current is provided when dynamic to the shunt capacitance of the feeder ear VDD of controller comprising: the first device of two starting IC and periphery
Part.Wherein bootrom IC1 and bootrom IC2 all has the characteristics of saturation high current, and bootrom IC2 band is opened and closed
There are return differences for disconnected control function, starting threshold value and shutdown threshold value.The bootrom IC1 input terminal and power supply of the start-up circuit are defeated
Enter VINConnection, output end are connected with the input terminal of bootrom IC2, and the output end of bootrom IC2 and the VDD of controller are supplied
Electric end connection, control terminal ground connection.
The utility model principle are as follows: when power supply just powers on, controller not yet starts, and the voltage of feeder ear VDD is 0V,
Input provides high current by bootrom IC1 and bootrom IC2 for controller, to give shunt capacitance CVDDCharging；Work as power supply
After the voltage of end VDD reaches controller starting voltage, controller starts to start, and G pulse drive signal is exported, due to controller
The charging rate of power consumption, VDD pin will slow down.Until when vdd terminal mouth voltage reaches the shutdown threshold value of bootrom IC2, starting
Chip IC 2 is closed, then bootrom IC1 is also accordingly turned off, i.e., start-up circuit is closed, and start-up circuit will be no longer from input electricity at this time
Pressure takes electricity, avoids additional power consumption penalty.Voltage Establishment to be output, controller are powered by auxiliary winding, start completion.
When controller is protected and turned off, energy needed for the quiescent operation of controller is supplied to feeder ear by shunt capacitance
VDD, when the voltage of feeder ear VDD drops to the starting point of bootrom IC2, start-up circuit is reopened, for being control
The feeder ear VDD of device provides high current, up to controller restarting, to rise to starting core in VDD to shunt capacitance charging
The shutdown threshold value of piece IC2, turns off start-up circuit, so repeats, and controller replaces open and close with start-up circuit, until
Controller detects that protection is eliminated.
As a kind of a kind of scheme of start-up circuit, including bootrom IC1, bootrom IC2, resistance R1, electricity
The input port 1 for hindering R2, capacitor C1 and capacitor C2, bootrom IC1 terminates power input V as the input of start-up circuitIN、
One end of resistance R1 and one end of filter capacitor C1；The other end and the other end of capacitor C1, one end of resistance R2, the electricity of resistance R1
The control terminal 3 of one end, bootrom IC1 for holding C2 connects, and the other end and the capacitor C2 other end of resistance R2 is connected to ground；Starting
The output end 2 of chip IC 1 is connected to the input terminal 2 of bootrom IC2, and the control terminal 3 of bootrom IC2 is grounded, bootrom
The output end 1 of IC2 terminates to the feeder ear of external controller as the output of start-up circuit, is that the feeder ear of controller supplies
Electricity.
After power supply electrifying, input controls the control terminal 3 of bootrom IC1 by electric resistance partial pressure, in low pressure input condition
Under, partial pressure value is kept above the shutdown threshold value of bootrom IC2, it can be ensured that bootrom IC2 is normally-open and closes；High pressure
Under the conditions of, above-mentioned electric resistance partial pressure ratio is equally applicable to the bootrom IC2 of low technique, can effectively evade pressure-resistant problem.
As another scheme of the start-up circuit, including bootrom IC1, bootrom IC2, resistance RL and pressure stabilizing
The input port 1 of diode Dz, bootrom IC1 terminate power input V as the input of start-up circuitIN；Zener diode Dz
Plus earth, the cathode of zener diode Dz is connected to the control terminal 3 of bootrom IC1 and one end of resistance RL, and resistance RL is another
One end is connected to the output end 2 of bootrom IC1 and the input terminal 2 of bootrom IC2；The control terminal 3 of bootrom IC2 connects
Ground, the output end 1 of bootrom IC2 terminates to the feeder ear of external controller as the output of start-up circuit, to bypass
Capacitor CVDDCharging；Under high input voltage, 3 voltage of control terminal of bootrom IC1 is clamped, while bootrom IC2's is defeated
Enter 2 voltages of end also clamper therewith, therefore the pressure-resistant problem of bootrom IC2 can not have to consider, get rid of it is technologic limited, and
Regulate and control without periphery.
Preferably, bootrom IC1 and bootrom IC2 has the characteristics that be saturated high current, and bootrom IC2 band is opened
It opens and turns off control function, there are return differences for the starting threshold value and shutdown threshold value of bootrom IC2.
Preferably, the resistance value of resistance RL is mega-ohms.
Brief analysis has been carried out to the implementation of the utility model and circuit theory, effect etc. above, it now will be originally practical
Novel beneficial effect is summarized as follows:
1, the utility model can solve the starting problem under ultra-wide AC or DC input voltage range, it can be achieved that inputting in low pressure
Lower normal starting, and start-up circuit is closed after controller starting, save power consumption.
2, big charging current is realized under the conditions of gamut voltage input, make that it is suitable for all kinds of controller IC applications.
3, device needed for start-up circuit is few, and peripheral structure is simple, and circuit theory is reliable, small in size, saves cost.
Detailed description of the invention
Fig. 1 is the circuit diagram that conventional linear voltage regulator circuit realizes controller starting；
Fig. 2 is the high-voltage starting circuit that the prior art realizes controller starting；
Fig. 3 is the start-up circuit functional block diagram of the utility model；
Fig. 4 is the functional block diagram of the start-up circuit embodiment one of the utility model；
Fig. 5 is that the start-up circuit embodiment one of the utility model realizes the waveform correlation of controller starting；
Fig. 6 opens machine test waveform for the utility model practical application；
Fig. 7 is that test waveform is restarted in the protection of the utility model practical application；
Fig. 8 is the functional block diagram of the start-up circuit embodiment two of the utility model.
Specific embodiment
In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with attached drawing and implementation
The utility model is further described in example.It should be appreciated that specific embodiment described herein is only used to explain this reality
With novel, it is not used to limit the utility model.
Embodiment one
Fig. 3 is circuit reduction figure of the utility model in the application scenarios of opto-coupled feedback flyback sourse, wherein being omitted
Secondary marginal ray coupling and TL431 and loop compensation part.Start-up circuit described in the utility model is the circuit part in dotted line frame, because outer
Enclosing can be not shown herein, detailed in Example there are many connection type, in addition its controller and other circuits and the utility model without
It closes, details are not described herein again.GT pin is the driving output of controller, for controlling being switched on and off for power tube M1；VDD pin
It is the power input pin of controller, for the power supply of controller, wherein VDD pin connects the output end of start-up circuit, can solve
Super wide range is inputted in VINThe problem of controller can not normally start in the case that voltage is very low.Controller shown in Fig. 3 its
Its pin connection relationship and function are unrelated with the utility model, therefore do not indicate in figure.
As shown in figure 4, being applied to the circuit diagram of Switching Power Supply first embodiment for the utility model start-up circuit.
Start-up circuit includes two starting IC, the resistance of two kilo-ohms of grades and the filter capacitor of two nanofarad ranges.Starting
The input port 1 of chip IC 1 meets power input VIN, and it is connected to one end of resistance R1 and one end of filter capacitor C1, resistance R1's
The other end of the other end and capacitor C1 are connected with one end of one end of resistance R2, capacitor C2, and are connected to the control of bootrom IC1
End 3 processed, the other end and the capacitor C2 other end of resistance R2 are connected to ground.The output end 2 of bootrom IC1 is connected to bootrom
The control terminal 3 of the input terminal 2 of IC2, bootrom IC2 is grounded, and the output end 1 of bootrom IC2 is connected to the feeder ear of controller
VDD。
The basic functional principle of the present embodiment:
After power supply electrifying, the control terminal voltage of IC1 is controlled by electric resistance partial pressure, so that control is flowed through from bootrom IC1
Electric current, bootrom IC2 control terminal is coupled directly to ground, realize that maximum current charges to the VDD shunt capacitance of controller, into
And realize the quick start of controller.
Realize that the implementation method started under high current and low pressure is as follows in this embodiment:
In bootrom IC1, the voltage of control terminal are as follows:
Bootrom IC1 is equivalent to one and exhausts metal-oxide-semiconductor, flows through electric current are as follows:
Wherein, Vs1 is the source voltage (i.e. 2 voltage of port) for exhausting pipe, and Vth is the turn-on threshold voltage for exhausting pipe.
Realize that metal-oxide-semiconductor work while saturation conduction state, can be controlled in starting when low pressure inputs by electric resistance partial pressure
The output voltage of chip IC 2 is more than that it starts voltage and shutdown threshold voltage, on the one hand can normally be started, on the other hand again can
To match the stress for reducing bootrom IC2 by resistance, thus realize that starting high current charges to controller, quick start.
Herein, the resistance selection magnitude suggestion of resistance pressure-dividing network is kilo-ohm grade, can guarantee the resistance in low pressure in this way
Partial pressure is accurate, while its dividing ratios should meet the starting and closedown condition of bootrom IC2.
VDD and GT pin voltage waveform when Fig. 5 is the controller starting of embodiment one, it can be seen that, it is powered in input
Afterwards, start-up circuit provides high current and quickly charges to VDD shunt capacitance, and by time T1, vdd voltage charges to controller starting
Point VVDD_ON, controller is started to work, and output pulse waveform, drives external power pipe, and transmit energy to secondary side by transformer
Amount, due to controller power consumption, VDD charging rate slows down, but charging current is greater than power consumption electric current, continues to charge, when passing through
Between T2, vdd voltage charges to the shutdown threshold value V of bootrom IC2IC2_OFF, bootrom IC2 shutdown, start-up circuit closing, section
Power consumption is saved, controller vdd terminal mouth voltage starts power down due to controller power consumption at this time, and by time T3, output voltage rises
To VOUT_min, and auxiliary winding voltage is transformed by transformer, loop begins setting up and tends towards stability, at this time controller VDD
Pin is powered by auxiliary winding.
As shown in fig. 6, actual test opens machine waveform diagram when for the utility model application, wherein GT pin is impulse wave
Shape needs in actual measurement to lengthen the testing time to observe the variation of start-up course VDD pin voltage and output establishment process, therefore GT
Pin waveform generates shade because intensive, and in addition GATE pin amplitude follows VDD to change, and keeps stablizing after output is established.By
It is close with the shutdown threshold value of bootrom IC2 in the starting voltage of controller design, it can be seen that rise to pass in vdd voltage
When breakpoint, start-up circuit is closed, and saves loss, while controller output pulse signal, controller vdd terminal mouth voltage is due to control
Device power consumption and start power down, when output is gradually built up, controller turns to be powered by auxiliary winding.As seen from Figure 6, starting
When, shunt capacitance (10uF) charging current are as follows:
It can be seen that charging current is very big, it can greatly reduce and open the machine time.
As shown in fig. 7, test waveform figure is restarted in the protection of actual test when applying for the utility model, wherein GT pin is
There is shade due to will lengthen the testing time in impulse waveform.When controller is protected and turned off, needed for the quiescent operation of controller
Energy is supplied to feeder ear VDD by shunt capacitance, when the voltage of feeder ear VDD drops to the starting point of bootrom IC2, opens
Dynamic circuit is reworked, and provides high current for the feeder ear VDD of controller, to charge to shunt capacitance until controller opens again
It is dynamic, in the closing threshold value that VDD rises to bootrom IC2, it is again switched off start-up circuit, is so repeated, controller and starting electricity
Road alternately opens and closes, until controller detects that protection is eliminated.
Embodiment two
As shown in figure 8, compared with embodiment one, difference is that not needing resistance realizes partial pressure, using voltage-stabiliser tube clamper,
Periphery is saved, and reduces the voltage stress of bootrom IC2, to directly use low pressure process IC.Such as Fig. 8, bootrom IC1
Input port 1 meet power input VIN, zener diode Dz plus earth, cathode is connected to the control terminal 3 of bootrom IC1, and
It is connected to one end of resistance RL, the resistance RL other end is connected to the output end 2 of bootrom IC1, and defeated with bootrom IC2
Enter end 2 to be connected.The control terminal 3 of bootrom IC2 is grounded, and output end 1 meets the feeder ear VDD of controller.
The basic functional principle of the present embodiment:
After power supply electrifying, bootrom IC1 and bootrom IC2 are opened, and start-up circuit generates high current to controller
The shunt capacitance of feeder ear VDD charges, and when vdd voltage reaches the shutdown threshold value of bootrom IC2, start-up circuit is closed, and is saved
Power consumption.After output voltage is gradually built up, controller starts to be powered by auxiliary winding.
Bootrom IC1 is equivalent to a NMOS tube, under low pressure input condition, 3 electricity of control terminal of bootrom IC1
Pressure will be charged to due to the parasitic capacitance between grid and drain electrode close to initial input voltage VIN, work as VINVoltage is higher than pincers
When the pipe breakdown voltage of position, 3 voltage of control terminal of bootrom IC1 will be clamped the clamp value in zener diode, to start
The input of chip IC 2 is then not necessarily to consider the pressure resistance of bootrom IC2, bootrom IC2 can make in this case also by clamper
With low pressure process, therefore bootrom IC2 can be limited with flexible choice and not by technique, even if technique change is still in application
It is old unaffected, can meet the needs of low cost, multi-scheme selection.
Herein, the resistance value of resistance RL selects mega-ohms, and ohmically pressure drop is that clamper tube voltage and bootrom IC2 are inputted
Difference in voltage, value very little, therefore working loss can be effectively reduced.
It should be understood that the utility model relates to the applications of start-up circuit, wherein use to two bootroms,
The function of this two bootroms is achieved in that known to person of ordinary skill in the field, the person skilled in the art
The implementation of technical solution can be realized according to the embodiment of the utility model, even if for two bootroms in specification
Inside is not described in detail, can not think that the operation instruction in specification for bootrom is insufficient.It closes
It, then can be by person of ordinary skill in the field according to demand and concrete technology in the selection of second bootrom IC2
It provides to make decision, the specific implementation method of this part should be known to a person skilled in the art.
The embodiments of the present invention is without being limited thereto, according to the above content of the utility model, utilizes the general of this field
Logical technological know-how and customary means, under the premise of not departing from the utility model above-mentioned basic fundamental thought, the utility model may be used also
To make the modification, replacement or change of other diversified forms, all fall within the utility model rights protection scope.
Claims (6)
1. a kind of start-up circuit, it is characterised in that: including bootrom IC1, bootrom IC2, resistance R1, resistance R2, capacitor
The input port 1 of C1 and capacitor C2, bootrom IC1 as start-up circuit input termination power input VIN, resistance R1 one
The one end at end and filter capacitor C1；The other end and the other end of capacitor C1 of resistance R1, one end of resistance R2, capacitor C2 one
The connection of control terminal 3 at end, bootrom IC1, the other end and the capacitor C2 other end of resistance R2 are connected to ground；Bootrom IC1
Output end 2 be connected to the input terminal 2 of bootrom IC2, the control terminal 3 of bootrom IC2 is grounded, and bootrom IC2's is defeated
Outlet 1 terminates to the feeder ear of external controller as the output of start-up circuit, is that the feeder ear of controller is powered.
2. start-up circuit according to claim 1, it is characterised in that: the bootrom IC1 and bootrom IC2 tool
Have the characteristics of saturation high current, and bootrom IC2 band opens and shuts off control function, the starting threshold value of bootrom IC2 with
Turning off threshold value, there are return differences.
3. start-up circuit according to claim 1, it is characterised in that: the resistance R1 and resistance R2 is the electricity of kilo-ohm grade
Resistance；The capacitor C1 and capacitor C2 is the filter capacitor of nanofarad range.
4. a kind of start-up circuit, it is characterised in that: including bootrom IC1, bootrom IC2, resistance RL and zener diode
The input port 1 of Dz, bootrom IC1 terminate power input VIN as the input of start-up circuit；The anode of zener diode Dz
Ground connection, the cathode of zener diode Dz are connected to the control terminal 3 of bootrom IC1 and one end of resistance RL, and the resistance RL other end connects
It is connected to the output end 2 of bootrom IC1 and the input terminal 2 of bootrom IC2；The control terminal 3 of bootrom IC2 is grounded, starting
The output end 1 of chip IC 2 terminates to the feeder ear of external controller as the output of start-up circuit, is the feeder ear of controller
Power supply.
5. start-up circuit according to claim 4, it is characterised in that: the bootrom IC1 and bootrom IC2 tool
Have the characteristics of saturation high current, and bootrom IC2 band opens and shuts off control function, the starting threshold value of bootrom IC2 with
Turning off threshold value, there are return differences.
6. start-up circuit according to claim 4, it is characterised in that: the resistance value of the resistance RL is mega-ohms.
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| CN201821842482.5U CN209016930U (en) | 2018-11-09 | 2018-11-09 | A kind of start-up circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109245513A (en) * | 2018-11-09 | 2019-01-18 | 深圳南云微电子有限公司 | A kind of start-up circuit |
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2018
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109245513A (en) * | 2018-11-09 | 2019-01-18 | 深圳南云微电子有限公司 | A kind of start-up circuit |
| CN109245513B (en) * | 2018-11-09 | 2024-04-09 | 深圳南云微电子有限公司 | Starting circuit |
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