CN109067163A - Soft starting circuit, control chip, buck converter and boost converter - Google Patents
Soft starting circuit, control chip, buck converter and boost converter Download PDFInfo
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- CN109067163A CN109067163A CN201810973169.3A CN201810973169A CN109067163A CN 109067163 A CN109067163 A CN 109067163A CN 201810973169 A CN201810973169 A CN 201810973169A CN 109067163 A CN109067163 A CN 109067163A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/36—Means for starting or stopping converters
-
- 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
- H02M1/32—Means for protecting converters other than automatic disconnection
- H02M1/34—Snubber circuits
-
- 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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1582—Buck-boost converters
-
- 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
- H02M1/32—Means for protecting converters other than automatic disconnection
- H02M1/34—Snubber circuits
- H02M1/344—Active dissipative snubbers
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention discloses a kind of soft starting circuits, control chip, buck converter and boost converter, soft starting circuit includes: operational amplifier, soft start comparator, clamp circuit, first switch and the second switch, when the branch pressure voltage of Switching Power Supply starting and the acquisition of soft start comparator normal phase input end is lower than the second reference voltage of inverting input terminal, soft start comparator exports low level signal, first switch shutdown, second switch conducting, soft starting circuit enters soft start state, the output voltage of operational amplifier is clamped circuit and is fixed on setting clamp voltage value；When the branch pressure voltage of Switching Power Supply starting and the acquisition of soft start comparator normal phase input end is higher than the second reference voltage, soft start comparator exports high level signal, and first switch is connected, and second switch shutdown, soft starting circuit terminates soft start.The present invention not only realizes soft start, and the dash current of voltage and inductance that soft start controls can be arranged according to different demands.
Description
Technical field
The present invention relates to start-up circuit technical fields, more specifically, being related to a kind of soft starting circuit, control chip, drop
Pressure converter and boost converter.
Background technique
When Switching Power Supply starting, to prevent from bringing biggish punching to inductance because booster circuit is too fast to reference voltage boosting
It hits electric current and damages device, generally control the dash current to inductance using soft starting circuit at present.
Traditional soft starting circuit slowly rises reference voltage by RC circuit, therefore, the time that reference voltage rises
Constant is determined by the size of RC.The speed for increase reference voltage is slower, keeps the dash current of inductance smaller, it is necessary to
Increase the resistance value of resistance in RC circuit, or the capacity or the resistance value of resistance and the capacity of capacitor of increase capacitor increase, from
And it needs to increase in power management chip for placing the area of RC circuit, and then increase the area of power management chip.
Summary of the invention
In view of this, the present invention discloses a kind of soft starting circuit, control chip, buck converter and boost converter, with
It solves in traditional scheme, it is slower in the speed for needing increase reference voltage, make the dash current more hour of inductance, because needing to increase
The resistance value of resistance and/or be to increase the capacity of capacitor, and lead to the problem of increasing the area of power management chip in big RC circuit.
A kind of soft starting circuit, comprising: operational amplifier, soft start comparator, clamp circuit, first switch and second open
It closes；
The normal phase input end of the operational amplifier connects one end of the first switch, the other end of the first switch
For inputting the first reference voltage, the first switch is off shape when the soft starting circuit is in soft start state
State；
The normal phase input end of the operational amplifier is grounded by the second switch, and the second switch soft is opened described
Dynamic circuit is in the conductive state when soft start state；
The inverting input terminal of the operational amplifier is used for the branch pressure voltage of input switch electric power output voltage；
The output end of the operational amplifier connects the clamp circuit；
The normal phase input end of the soft start comparator for inputting the branch pressure voltage, the soft start comparator it is anti-
Phase input terminal connects the control terminal of the first switch for inputting the second reference voltage, the output end of the soft start comparator
With the control terminal of the second switch；
The output end of the soft start comparator is used in Switching Power Supply starting and the branch pressure voltage is lower than described
When the second reference voltage, low level signal is exported, turns off the first switch, the second switch conducting, the soft start
Circuit enters soft start state, and the output voltage of the operational amplifier is fixed on setting clamp voltage by the clamp circuit
Value；It is also used to when the Switching Power Supply starts and the branch pressure voltage is higher than second reference voltage, output high level letter
Number, the first switch is connected, the second switch shutdown, the soft starting circuit terminates soft start.
Preferably, further includes: first resistor；
The first resistor is arranged between the second switch and ground.
Preferably, further includes: sample circuit；
The input terminal of the sample circuit connects sample port, and the sample port is for inputting the Switching Power Supply output
Voltage, the output end of the sample circuit respectively with the inverting input terminal of the operational amplifier and the soft start comparator
Normal phase input end connection, the output end of the sample circuit are used to export the partial pressure electricity of the switch power source output voltage
Pressure.
Preferably, the sample circuit includes: second resistance and 3rd resistor, described in one end connection of the second resistance
The other end of sample port, the second resistance is grounded by the 3rd resistor, the second resistance and the 3rd resistor
Output end of the common end as the sample circuit.
A kind of control chip, comprising: soft starting circuit described above, logic circuit, slope compensation circuit, compensation network
Circuit, third switch and the 4th switch；
Output of the common end of the output end of the output end and clamp circuit of operational amplifier as the soft starting circuit
End, connect with the first input end of the logic circuit, the second input terminal and the slope compensation circuit of the logic circuit
Output end connection, the output end of the logic circuit be separately connected third switch control terminal and the 4th switch
Control terminal, one end of the third switch connect the first port of the control chip, and the other end of the third switch passes through
The 4th switch ground connection, the third switch connect the second end of the control chip with the common end of the 4th switch
Mouthful；
The output end of the compensation network circuit is separately connected the logic circuit, the clamp circuit and the operation and puts
The output end of big device, the compensation network circuit are used for the zero pole point of compensation loop；
The setting clamp voltage value and the slope that the output voltage of the operational amplifier is fixed by the clamp circuit
After the ramp voltage value that compensation circuit generates is input to the logic circuit, the switching signal of a fixed duty cycle, institute are generated
Switching signal is stated by driving the third switch and the 4th switch, increases the output voltage of the sample port.
A kind of buck converter, including control chip and the first filter circuit described above；
The first port of the control chip is the input port of the buck converter；
The second port of the control chip is the output port of the buck converter, and the output port passes through described
First filter circuit is connect with the sample port in soft starting circuit.
Preferably, first filter circuit includes: the first inductance, first capacitor and the first load resistance；
One end of first inductance connects the defeated of the buck converter as the input terminal of first filter circuit
Exit port, the other end of first inductance be separately connected the positive plate of the first capacitor, first load resistance one
One end of end and the sample port, the negative plate of the first capacitor and first load resistance is grounded.
A kind of boost converter, including control chip described above, the second inductance and the second filter circuit；
The first port of the control chip is the output port of the boost converter, the output port and soft start
Sample port connection in circuit, and, the output port is grounded by second filter circuit；
The first port of the control chip is connect with one end of second inductance, and the other end of second inductance is made
For the input port of the boost converter.
Preferably, second filter circuit includes: the second capacitor and the second load resistance；
The positive plate of second capacitor connects the output port, the cathode plate earthing of second capacitor；
One end of second load resistance connects the output port, one end ground connection of second load resistance.
From above-mentioned technical solution it is found that the invention discloses a kind of soft starting circuit, control chip, buck converter and
Boost converter, soft starting circuit include: that operational amplifier, soft start comparator, clamp circuit, first switch and second are opened
It closes, when the branch pressure voltage of Switching Power Supply starting and the acquisition of soft start comparator normal phase input end is lower than the second base of inverting input terminal
When quasi- voltage, soft start comparator exports low level signal, first switch shutdown, second switch conducting, soft starting circuit entrance
Soft start state, the output voltage of operational amplifier are clamped circuit and are fixed on setting clamp voltage value；When Switching Power Supply starts
And the branch pressure voltage of soft start comparator normal phase input end acquisition is when being higher than the second reference voltage, the high electricity of soft start comparator output
Ordinary mail number, first switch conducting, second switch shutdown, soft starting circuit terminate soft start.Soft starting circuit disclosed by the invention
It is real by increasing by two switches on the basis of the existing operational amplifier of traditional circuit, soft start comparator and clamp circuit
Existing soft start, and the reference voltage of soft start comparator can be changed according to different demands, soft starting control electric pressure is set；Change
The clamp voltage value for becoming clamp circuit setting removes the dash current of control inductance, is needing to make base accordingly, with respect to traditional scheme
The speed that quasi- voltage rises is slower, makes the dash current more hour of inductance, needs to increase the resistance value and/or increasing of resistance in RC circuit
For the capacity of bulky capacitor, the present invention can effectively reduce circuit area, to can be widely applied in power management chip.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
The embodiment of invention for those of ordinary skill in the art without creative efforts, can also basis
Disclosed attached drawing obtains other attached drawings.
Fig. 1 is a kind of circuit diagram of soft starting circuit disclosed by the embodiments of the present invention；
Fig. 2 is the circuit diagram of another soft starting circuit disclosed by the embodiments of the present invention；
Fig. 3 is a kind of circuit diagram for controlling chip disclosed by the embodiments of the present invention；
Fig. 4 is a kind of circuit diagram of buck converter disclosed by the embodiments of the present invention；
Fig. 5 is a kind of circuit diagram of boost converter disclosed by the embodiments of the present invention；
Fig. 6 is a kind of soft start simulation waveform based on boost converter disclosed by the embodiments of the present invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
It is soft to open the embodiment of the invention discloses a kind of soft starting circuit, control chip, buck converter and boost converter
Dynamic circuit includes: operational amplifier, soft start comparator, clamp circuit, first switch and the second switch, when Switching Power Supply starts
And soft start comparator normal phase input end acquisition branch pressure voltage be lower than inverting input terminal the second reference voltage when, soft start ratio
Low level signal, first switch shutdown are exported compared with device, second switch is connected, and soft starting circuit enters soft start state, and operation is put
The output voltage of big device is clamped circuit and is fixed on setting clamp voltage value；When Switching Power Supply starting and soft start comparator positive
When the branch pressure voltage of input terminal acquisition is higher than the second reference voltage, soft start comparator exports high level signal, and first switch is led
Logical, second switch shutdown, soft starting circuit terminates soft start.Soft starting circuit disclosed by the invention is in the existing fortune of traditional circuit
On the basis of calculating amplifier, soft start comparator and clamp circuit, by increasing by two switches, soft start is realized.And it can root
According to different demands, change the reference voltage of soft start comparator, soft starting control electric pressure is set；Change the pincers of clamp circuit setting
Position voltage value removes the dash current of control inductance, is needing to make the speed of reference voltage rising more accordingly, with respect to traditional scheme
Slowly, the dash current more hour for making inductance needs to increase in RC circuit for the capacity of the resistance value of resistance and/or increase capacitor,
The present invention can effectively reduce circuit area, to can be widely applied in power management chip.
Referring to Fig. 1, a kind of circuit diagram of soft starting circuit disclosed in one embodiment of the invention, soft starting circuit includes: fortune
Calculate amplifier EA, soft start comparator COMP, clamp circuit 11, first switch K1 and second switch K2；
Wherein:
One end of the normal phase input end connection first switch K1 of operational amplifier EA, the other end of first switch K1 is for defeated
Enter the first reference voltage Vref1, first switch K1 is in an off state when soft starting circuit is in soft start state.
The normal phase input end connection of operational amplifier EA is grounded by second switch K2, and second switch K2 is in soft starting circuit
It is in the conductive state when in soft start state.
The inverting input terminal of operational amplifier EA is used for the branch pressure voltage VFB of input switch electric power output voltage.
The output end of operational amplifier EA connects clamp circuit 11, and the output voltage EAOUT of operational amplifier EA is clamped
Circuit 11 is fixed on setting clamp voltage value.
For the normal phase input end of soft start comparator COMP for inputting branch pressure voltage VFB, soft start comparator COMP's is anti-
Phase input terminal is for inputting the second reference voltage Vref2, the control of the output end connection first switch K1 of soft start comparator COMP
The control terminal at end processed and second switch K2.
Wherein, the specific value depend on the actual needs of the first reference voltage Vref1 and the second reference voltage Vref2,
The value of first reference voltage Vref1 and the second reference voltage Vref2 can be identical or different, for example, when the first benchmark electricity
When pressing the value difference of Vref1 and the second reference voltage Vref2, the first reference voltage Vref1 and the second reference voltage Vref2's
Value can differ 5% or other values.
The output end of soft start comparator COMP is used in Switching Power Supply starting and branch pressure voltage VFB is lower than the second benchmark electricity
When pressing Vref2, low level signal is exported, turns off first switch K1, second switch K2 conducting, the soft starting circuit enters soft
Starting state, the output voltage of operational amplifier EA are clamped circuit 11 and are fixed on setting clamp voltage value；
The output end of soft start comparator COMP is also used to start in Switching Power Supply and branch pressure voltage VFB is higher than the second benchmark
When voltage Vref2, high level signal is exported, first switch K1 is connected, second switch K2 shutdown, soft starting circuit terminates soft open
It is dynamic.
For convenience of understanding, the working principle of soft starting circuit shown in FIG. 1 is specifically described below as follows:
When Switching Power Supply starting, the switch power source output voltage of the normal phase input end acquisition of soft start comparator COMP
When branch pressure voltage VFB is lower than the second reference voltage Vref2, soft start comparator COMP exports low level signal, indicates soft start
Circuit enters soft start state, and first switch K1 is turned off under the control of low level signal, the positive input of operational amplifier EA
Connection between end and the port for exporting the first reference voltage Vref1 disconnects, and stops the first reference voltage Vref1 of input；
Meanwhile second switch K2 is connected under the control of low level signal, and the normal phase input end of operational amplifier EA is made to pass through the first electricity
R1 ground connection is hindered, at this moment, the output voltage EAOUT of operational amplifier EA can be pulled low, and it is solid that output voltage EAOUT is clamped circuit 11
It is scheduled on setting clamp voltage value.
When Switching Power Supply starts, the switch power source output voltage of the normal phase input end acquisition of soft start comparator COMP divides
When piezoelectricity presses VFB to be higher than the second reference voltage Vref2, soft start comparator COMP exports high level signal, indicates soft start electricity
Road soft start terminates, at this point, first switch K1 is connected under the control of high level signal, second switch K2 is in high level signal
The lower shutdown of control, disconnects the connection between the normal phase input end of operational amplifier EA and first resistor R1, operational amplifier EA
Normal phase input end input the first reference voltage Vref1 again.
In summary, soft starting circuit disclosed by the invention, when Switching Power Supply starting and soft start comparator positive inputs
When the branch pressure voltage VFB of end acquisition is lower than the second reference voltage Vref2 of inverting input terminal, soft start comparator COMP output is low
Level signal, first switch K1 shutdown, second switch K2 conducting, soft starting circuit enter soft start state, operational amplifier EA
Output voltage be clamped circuit 11 and be fixed on setting clamp voltage value；When Switching Power Supply starting and soft start comparator COMP is just
When the branch pressure voltage VFB of phase input terminal acquisition is higher than the second reference voltage Vref2, soft start comparator COMP exports high level letter
Number, first switch K1 conducting, second switch K2 is turned off, and soft starting circuit terminates soft start.Soft starting circuit disclosed by the invention
On the basis of the existing operational amplifier EA of traditional circuit, soft start comparator COMP and clamp circuit 11, by increasing by two
A switch realizes soft start, and can change the reference voltage of soft start comparator COMP according to different demands, and soft open is arranged
Dynamic control voltage；Change the dash current that the clamp voltage value that clamp circuit 11 is set removes control inductance, accordingly, with respect to tradition
Scheme is slower in the speed for needing increase reference voltage, makes the dash current more hour of inductance, needs to increase electric in RC circuit
For the resistance value of resistance and/or the capacity of increase capacitor, the present invention can effectively reduce circuit area, to can be widely applied to electricity
In source control chip.
Preferably, first switch K1 and second switch K2 is metal-oxide-semiconductor.
In order to further optimize the above embodiments, referring to fig. 2, a kind of soft starting circuit disclosed in another embodiment of the present invention
Circuit diagram, on the basis of embodiment shown in Fig. 1, soft starting circuit can also include: first resistor R1, first resistor R1 setting
Between second switch K2 and ground, it to be used for current limliting.
In order to further optimize the above embodiments, soft starting circuit can also include: sample circuit；
The input terminal of the sample circuit connects sample port VOUT, and the sample port is exported for input switch power supply
Voltage, the output end of sample circuit are defeated with the positive of the inverting input terminal of operational amplifier EA and soft start comparator COMP respectively
Enter end connection, the output end of sample circuit is used for the branch pressure voltage VFB of output switch power source output voltage.
Specifically, sample circuit may include: second resistance R2 and 3rd resistor R3, one end connection of second resistance R2 is adopted
The other end of sample port VOUT, second resistance R2 are grounded by 3rd resistor R3, and second resistance R2 and 3rd resistor R3's is public
Hold the output end as the sample circuit, the branch pressure voltage VFB for output switch power source output voltage.
From figure 2 it can be seen that the practical voltage for being 3rd resistor R3 of the branch pressure voltage VFB of switch power source output voltage,
Therefore, the normal phase input end actual acquisition of the reverse input end of operational amplifier EA and soft start comparator COMP is third electricity
Hinder the voltage of R3.
Referring to Fig. 3, a kind of circuit diagram controlling chip disclosed in one embodiment of the invention, controlling chip includes:
Soft starting circuit, logic circuit 12, slope compensation circuit 13, compensation network circuit 14 in embodiment illustrated in fig. 2,
Third switch S1 and the 4th switch S2；
Wherein: the common end of the output end of the output end and clamp circuit 11 of operational amplifier EA is as the soft start electricity
The output end on road is connect with the first input end of the logic circuit 12, the second input terminal of the logic circuit 12 with it is described
The output end of slope compensation circuit 13 connects, and the output end of the logic circuit 12 is separately connected the control of the third switch S1
The control terminal at end and the 4th switch S4, one end of the third switch S1 connect the first port A for controlling chip, and described the
The other end of three switch S1 is grounded by the 4th switch S2, the common end of the third switch S1 and the 4th switch S2
The second port B of connection control chip；
The output end of compensation network circuit 14 is separately connected the logic circuit 12, the clamp circuit 11 and the operation
The output end of amplifier EA, compensation network circuit 14 are used for the zero pole point of compensation loop, guarantee the steady operation of circuit.
The output voltage of operational amplifier EA is by the fixed setting clamp voltage value of the clamp circuit 11 and the slope
After the ramp voltage value that compensation circuit 13 generates is input to the logic circuit 12, the switch letter an of fixed duty cycle is generated
Number, the switching signal is made at the sample port VOUT by driving the third switch S1 and the 4th switch S2
Output voltage increases.
For convenience of understanding, the working principle of control chip shown in Fig. 3 is specifically described below as follows:
When Switching Power Supply starting, the switch power source output voltage of the normal phase input end acquisition of soft start comparator COMP
When branch pressure voltage VFB is lower than the second reference voltage Vref2, soft start comparator COMP exports low level signal, indicates soft start
Circuit enters soft start state, and first switch K1 is turned off under the control of low level signal, the positive input of operational amplifier EA
Connection between end and the port for exporting the first reference voltage Vref1 disconnects, and stops the first reference voltage Vref1 of input；
Meanwhile second switch K2 is connected under the control of low level signal, and the normal phase input end of operational amplifier EA is made to pass through the first electricity
R1 ground connection is hindered, at this moment, the output voltage EAOUT of operational amplifier EA can be pulled low, and it is solid that output voltage EAOUT is clamped circuit 11
It is scheduled on setting clamp voltage value, the ramp voltage value that setting clamp voltage value and slope compensation circuit 13 generate is input to logic
Circuit 12, logic circuit 12 generate a fixation and account for by carrying out logical process to setting clamp voltage value and ramp voltage value
The switching signal of empty ratio, the switching signal drive third switch S1 and the 4th switch S2.
When Switching Power Supply starts, the switch power source output voltage of the normal phase input end acquisition of soft start comparator COMP divides
When piezoelectricity presses VFB to be higher than the second reference voltage Vref2, soft start comparator COMP exports high level signal, indicates soft start electricity
Road soft start terminates, at this point, first switch K1 is connected under the control of high level signal, second switch K2 is in high level signal
The lower shutdown of control, disconnects the connection between the normal phase input end of operational amplifier EA and first resistor R1, operational amplifier EA
Normal phase input end input the first reference voltage Vref1 again.
In summary, control chip disclosed by the invention compares in the existing operational amplifier EA of traditional circuit, soft start
On the basis of device COMP and clamp circuit 11, pass through and increase by two switches and a resistance, realizes soft start.And it can be according to not
Same demand changes the reference voltage of soft start comparator COMP, and soft starting control electric pressure is arranged；Change what clamp circuit 11 was set
Clamp voltage value removes the dash current of control inductance, accordingly, with respect to traditional scheme in the speed for needing increase reference voltage
It is slower, make the dash current more hour of inductance, need to increase the resistance value of resistance in RC circuit and/or increase capacitor capacity and
Speech, the present invention can effectively reduce circuit area, to can be widely applied in power management chip.
Referring to fig. 4, a kind of circuit diagram of buck converter, buck converter disclosed in one embodiment of the invention include: Fig. 3
Shown in control chip and the first filter circuit；
The first port A that chip is controlled in embodiment illustrated in fig. 3 is the input port of buck converter in the present embodiment
VIN；
The second port B that chip is controlled in embodiment illustrated in fig. 3 is the output port of buck converter in the present embodiment
SW, output port SW are connect by the first filter circuit with the sample port VOUT in soft starting circuit.
Specifically, filter circuit includes: the first inductance L1, first capacitor C1 and the first load resistance R4；
One end of first inductance L1 connects the output port of the buck converter as the input terminal of the first filter circuit
SW, the other end of the first inductance L1 are separately connected the positive plate of first capacitor C1, one end of the first load resistance R4 and described
One end of sample port VOUT, the negative plate of first capacitor C1 and the first load resistance R4 are grounded.
For convenience of understanding, the working principle of buck converter shown in Fig. 4 is specifically described below as follows:
When Switching Power Supply starting, the switch power source output voltage of the normal phase input end acquisition of soft start comparator COMP
When branch pressure voltage VFB is lower than the second reference voltage Vref2, soft start comparator COMP exports low level signal, indicates soft start
Circuit enters soft start state, and first switch K1 is turned off under the control of low level signal, the positive input of operational amplifier EA
Connection between end and the port for exporting the first reference voltage Vref1 disconnects, and stops the first reference voltage Vref1 of input；
Meanwhile second switch K2 is connected under the control of low level signal, and the normal phase input end of operational amplifier EA is made to pass through the first electricity
R1 ground connection is hindered, at this moment, the output voltage EAOUT of operational amplifier EA can be pulled low, and it is solid that output voltage EAOUT is clamped circuit 11
It is scheduled on setting clamp voltage value, the ramp voltage value that setting clamp voltage value and slope compensation circuit 13 generate is input to logic
Circuit 12, logic circuit 12 generate a fixation and account for by carrying out logical process to setting clamp voltage value and ramp voltage value
The switching signal of empty ratio, which drives third switch S1 and the 4th switch S2, to make defeated at sample port VOUT
Voltage increases out, and second resistance R2 and 3rd resistor R3 divide the output voltage at sample port VOUT, obtained point
Piezoelectricity presses VFB, and branch pressure voltage VFB is fed back to the normal phase input end of soft start comparator COMP.
When Switching Power Supply starts, the switch power source output voltage of the normal phase input end acquisition of soft start comparator COMP divides
When piezoelectricity presses VFB to be higher than the second reference voltage Vref2, soft start comparator COMP exports high level signal, indicates soft start electricity
Road soft start terminates, at this point, first switch K1 is connected under the control of high level signal, second switch K2 is in high level signal
The lower shutdown of control, disconnects the connection between the normal phase input end of operational amplifier EA and first resistor R1, operational amplifier EA
Normal phase input end input the first reference voltage Vref1 again.
In summary, in buck converter disclosed by the invention, soft starting circuit is in the existing operation of conventional buck circuit
On the basis of amplifier EA, soft start comparator COMP and clamp circuit 11, by increasing by two switches and a resistance, realize
It is depressured soft start.And the reference voltage of soft start comparator COMP can be changed according to different demands, soft starting control electric is set
Pressure；Change the dash current that the clamp voltage value that clamp circuit 11 is set removes control inductance, is being needed accordingly, with respect to traditional scheme
The speed for increase reference voltage is slower, makes the dash current more hour of inductance, needs to increase the resistance value of resistance in RC circuit
And/or for increasing the capacity of capacitor, the present invention can effectively reduce circuit area, to can be widely applied to power management core
In piece.
Referring to Fig. 5, a kind of circuit diagram of boost converter, boost converter include: Fig. 3 disclosed in one embodiment of the invention
Shown in control chip, the second inductance L2 and the second filter circuit；
The first port A that chip is controlled in embodiment illustrated in fig. 3 is the output port of boost converter in the present embodiment
VOUT1, the output port VOUT1 are connect with the sample port VOUT2 in soft starting circuit, and, the output port VOUT1
It is grounded by second filter circuit；
The second port B that chip is controlled in embodiment illustrated in fig. 3 is the port SW of boost converter, end in the present embodiment
Mouth SW is connect with one end of the second inductance L2, input port VIN of the other end of the second inductance L2 as boost converter.
Specifically, the second filter circuit includes: the second capacitor C2 and the second load resistance R5；
The positive plate of the second capacitor C2 connects the output port VOUT1, and the negative plate of the second capacitor C2 connects
Ground；
One end of the second load resistance R5 connects the output port VOUT1, and the one of the second load resistance R5
End ground connection.
For convenience of understanding, the working principle of boost converter shown in fig. 5 is specifically described below as follows:
When Switching Power Supply starting, the switch power source output voltage of the normal phase input end acquisition of soft start comparator COMP
When branch pressure voltage VFB is lower than the second reference voltage Vref2, soft start comparator COMP exports low level signal, indicates soft start
Circuit enters soft start state, and first switch K1 is turned off under the control of low level signal, the positive input of operational amplifier EA
Connection between end and the port for exporting the first reference voltage Vref1 disconnects, and stops the first reference voltage Vref1 of input；
Meanwhile second switch K2 is connected under the control of low level signal, and the normal phase input end of operational amplifier EA is made to pass through the first electricity
R1 ground connection is hindered, at this moment, the output voltage EAOUT of operational amplifier EA can be pulled low, and it is solid that output voltage EAOUT is clamped circuit 11
It is scheduled on setting clamp voltage value, the ramp voltage value that setting clamp voltage value and slope compensation circuit 13 generate is input to logic
Circuit 12, logic circuit 12 generate a fixation and account for by carrying out logical process to setting clamp voltage value and ramp voltage value
The switching signal of empty ratio, which drives third switch S1 and the 4th switch S2, to make defeated at sample port VOUT
Voltage increases out, and second resistance R2 and 3rd resistor R3 divide the output voltage at sample port VOUT, obtained point
Piezoelectricity presses VFB, and branch pressure voltage VFB is fed back to the normal phase input end of soft start comparator COMP.
When Switching Power Supply starts, the switch power source output voltage of the normal phase input end acquisition of soft start comparator COMP divides
When piezoelectricity presses VFB to be higher than the second reference voltage Vref2, soft start comparator COMP exports high level signal, indicates soft start electricity
Road soft start terminates, at this point, first switch K1 is connected under the control of high level signal, second switch K2 is in high level signal
The lower shutdown of control, disconnects the connection between the normal phase input end of operational amplifier EA and first resistor R1, operational amplifier EA
Normal phase input end input the first reference voltage Vref1 again.
In summary, in boost converter disclosed by the invention, soft starting circuit is in the existing operation of conventional buck circuit
On the basis of amplifier EA, soft start comparator COMP and clamp circuit 11, by increasing by two switches and a resistance, realize
It is depressured soft start.And the reference voltage of soft start comparator COMP can be changed according to different demands, soft starting control electric is set
Pressure；Change the dash current that the clamp voltage value that clamp circuit 11 is set removes control inductance, is being needed accordingly, with respect to traditional scheme
The speed for increase reference voltage is slower, makes the dash current more hour of inductance, needs to increase the resistance value of resistance in RC circuit
And/or for increasing the capacity of capacitor, the present invention can effectively reduce circuit area, to can be widely applied to power management core
In piece.
To prove that soft starting circuit provided by the invention may be implemented boosting soft start, the present invention also to boost converter into
Soft start simulation waveform of having gone experiment, simulation waveform shown in Figure 5, the simulation waveform are the clamper electricity that clamp circuit 11 is set
Pressure value is 700mV, and the switch power source output voltage of sample port VOUT acquisition is 5.05V.Thus illustrate, in the clamper electricity of setting
Under pressure value, soft starting circuit provided by the invention can effectively control the dash current of inductance, to guarantee that booster is opened soft
The stability of inductive current during dynamic.
Finally, it is to be noted that, herein, relational terms such as first and second and the like be used merely to by
One entity or operation are distinguished with another entity or operation, without necessarily requiring or implying these entities or operation
Between there are any actual relationship or orders.Moreover, the terms "include", "comprise" or its any other variant meaning
Covering non-exclusive inclusion, so that the process, method, article or equipment for including a series of elements not only includes that
A little elements, but also including other elements that are not explicitly listed, or further include for this process, method, article or
The intrinsic element of equipment.In the absence of more restrictions, the element limited by sentence "including a ...", is not arranged
Except there is also other identical elements in the process, method, article or apparatus that includes the element.
Each embodiment in this specification is described in a progressive manner, the highlights of each of the examples are with other
The difference of embodiment, the same or similar parts in each embodiment may refer to each other.
The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention.
Various modifications to these embodiments will be readily apparent to those skilled in the art, as defined herein
General Principle can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, of the invention
It is not intended to be limited to the embodiments shown herein, and is to fit to and the principles and novel features disclosed herein phase one
The widest scope of cause.
Claims (9)
1. a kind of soft starting circuit characterized by comprising operational amplifier, soft start comparator, clamp circuit, first open
Pass and second switch；
The normal phase input end of the operational amplifier connects one end of the first switch, and the other end of the first switch is used for
The first reference voltage is inputted, the first switch is in an off state when the soft starting circuit is in soft start state；
The normal phase input end of the operational amplifier is grounded by the second switch, and the second switch is in the soft start electricity
Road is in the conductive state when soft start state；
The inverting input terminal of the operational amplifier is used for the branch pressure voltage of input switch electric power output voltage；
The output end of the operational amplifier connects the clamp circuit；
For the normal phase input end of the soft start comparator for inputting the branch pressure voltage, the reverse phase of the soft start comparator is defeated
Enter end and connects control terminal and the institute of the first switch for inputting the second reference voltage, the output end of the soft start comparator
State the control terminal of second switch；
The output end of the soft start comparator is used in Switching Power Supply starting and the branch pressure voltage is lower than described second
When reference voltage, low level signal is exported, turns off the first switch, the second switch conducting, the soft starting circuit
Into soft start state, the output voltage of the operational amplifier is fixed on setting clamp voltage value by the clamp circuit；Also
For exporting high level signal, making when the Switching Power Supply starts and the branch pressure voltage is higher than second reference voltage
The first switch conducting, the second switch shutdown, the soft starting circuit terminate soft start.
2. soft starting circuit according to claim 1, which is characterized in that further include: first resistor；
The first resistor is arranged between the second switch and ground.
3. soft starting circuit according to claim 1, which is characterized in that further include: sample circuit；
The input terminal of the sample circuit connects sample port, and the sample port is for inputting the Switching Power Supply output electricity
Pressure, the output end of the sample circuit respectively with the inverting input terminal of the operational amplifier and the soft start comparator just
The connection of phase input terminal, the output end of the sample circuit are used to export the branch pressure voltage of the switch power source output voltage.
4. soft starting circuit according to claim 3, which is characterized in that the sample circuit includes: second resistance and
Three resistance, one end of the second resistance connect the sample port, and the other end of the second resistance passes through the third electricity
Output end of the common end of resistance ground connection, the second resistance and the 3rd resistor as the sample circuit.
5. a kind of control chip characterized by comprising soft starting circuit described in claim 1-4 any one, logic electricity
Road, slope compensation circuit, compensation network circuit, third switch and the 4th switch；
Output end of the common end of the output end of the output end and clamp circuit of operational amplifier as the soft starting circuit, with
The first input end of the logic circuit connects, the output of the second input terminal and the slope compensation circuit of the logic circuit
End connection, the output end of the logic circuit are separately connected the control terminal of the third switch and the control of the 4th switch
End, one end of the third switch connect the first port of the control chip, and the other end of the third switch passes through described
4th switch ground connection, the third switch connect the second port of the control chip with the common end of the 4th switch；
The output end of the compensation network circuit is separately connected the logic circuit, the clamp circuit and the operational amplifier
Output end, the compensation network circuit be used for compensation loop zero pole point；
The setting clamp voltage value and the slope compensation that the output voltage of the operational amplifier is fixed by the clamp circuit
After the ramp voltage value that circuit generates is input to the logic circuit, the switching signal of a fixed duty cycle is generated, it is described to open
OFF signal increases the output voltage of the sample port by driving the third switch and the 4th switch.
6. a kind of buck converter, which is characterized in that including the control chip and the first filter circuit described in claim 5；
The first port of the control chip is the input port of the buck converter；
The second port of the control chip is the output port of the buck converter, and the output port passes through described first
Filter circuit is electrically connected with the sample port in soft starting circuit.
7. buck converter according to claim 6, which is characterized in that first filter circuit include: the first inductance,
First capacitor and the first load resistance；
One end of first inductance connects the output end of the buck converter as the input terminal of first filter circuit
Mouthful, the other end of first inductance be separately connected the positive plate of the first capacitor, first load resistance one end and
One end of the sample port, the negative plate of the first capacitor and first load resistance is grounded.
8. a kind of boost converter, which is characterized in that including control chip, the second inductance and second described in claim 5
Filter circuit；
The first port of the control chip is the output port of the boost converter, the output port and soft starting circuit
In sample port electrical connection, and, the output port by second filter circuit ground connection；
The first port of the control chip is connect with one end of second inductance, and the other end of second inductance is as institute
State the input port of boost converter.
9. boost converter according to claim 8, which is characterized in that second filter circuit includes: the second capacitor
With the second load resistance；
The positive plate of second capacitor connects the output port, the cathode plate earthing of second capacitor；
One end of second load resistance connects the output port, one end ground connection of second load resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810973169.3A CN109067163A (en) | 2018-08-24 | 2018-08-24 | Soft starting circuit, control chip, buck converter and boost converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810973169.3A CN109067163A (en) | 2018-08-24 | 2018-08-24 | Soft starting circuit, control chip, buck converter and boost converter |
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| Publication Number | Publication Date |
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| CN109067163A true CN109067163A (en) | 2018-12-21 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810973169.3A Pending CN109067163A (en) | 2018-08-24 | 2018-08-24 | Soft starting circuit, control chip, buck converter and boost converter |
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| CN (1) | CN109067163A (en) |
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| CN112332665A (en) * | 2019-08-05 | 2021-02-05 | 成都锐成芯微科技股份有限公司 | Switching power supply control device |
| CN114531026A (en) * | 2022-04-21 | 2022-05-24 | 深圳英集芯科技股份有限公司 | Multiphase step-down conversion circuit, device and equipment |
| CN114661081A (en) * | 2020-12-22 | 2022-06-24 | 深圳英集芯科技股份有限公司 | Power supply soft start control circuit, control chip and control device |
| CN117040263A (en) * | 2023-08-03 | 2023-11-10 | 北京伽略电子股份有限公司 | Soft start circuit |
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