CN207069897U - Start-up circuit and inverse-excitation type switch power-supply - Google Patents
Start-up circuit and inverse-excitation type switch power-supply Download PDFInfo
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- CN207069897U CN207069897U CN201720805835.3U CN201720805835U CN207069897U CN 207069897 U CN207069897 U CN 207069897U CN 201720805835 U CN201720805835 U CN 201720805835U CN 207069897 U CN207069897 U CN 207069897U
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- 230000005611 electricity Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 230000005669 field effect Effects 0.000 description 4
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000000087 stabilizing Effects 0.000 description 1
Abstract
The utility model provides a kind of start-up circuit and inverse-excitation type switch power-supply, and the start-up circuit includes the first start unit, the second start unit and starts reset unit；Wherein：The input of first start unit and the second start unit is connected respectively to power supply；The output end for starting reset unit and being connected to the second start unit, and the startup reset unit turns on when it is the second predeterminated voltage to control terminal voltage；The output end of second start unit is connected to the control terminal of first start unit and the first predeterminated voltage is exported in the startup reset unit cut-off, exports the 3rd predeterminated voltage in the startup reset unit conducting, and the 3rd predeterminated voltage is less than the first predeterminated voltage；First start unit is exported when control terminal reaches the first predeterminated voltage by output end starts voltage.The utility model can not only realize quick startup, and can reduce the power consumption of whole start-up circuit.
Description
Technical field
Field of switch power is the utility model is related to, more specifically to a kind of start-up circuit and flyback switching electricity
Source.
Background technology
Inverse-excitation type switch power-supply is widely used in the power supply of electronic product with the advantages that its cost is low, small volume.Such as
It is typical inverse-excitation type switch power-supply schematic diagram shown in Fig. 1, is electric capacity C1 first by starting resistance R1 after power supply energization
Charging, and control chip is started working when electric capacity C1 voltage reaches predetermined value；Control chip passes through V afterwardsGPin is defeated
Go out predetermined level, turn on switching tube Q1, so as to by being control chip around the auxiliary power supply winding being located on transformer T1
Work.
In the inverse-excitation type switch power-supply system that high pressure, wide scope input, in order to improve a machine time for system, it is necessary to subtract
The small resistance value for starting resistance R1, but as the resistance value for starting resistance R1 reduces, the power consumption started on resistance R1 can increase,
So as to reduce the efficiency of system.Also, the temperature rise for starting resistance R1 itself also can be very high.And start resistance R1's to reduce
Damage, the resistance value for starting resistance R1 need to be increased as far as possible, but this has caused the machine time very long again.
Utility model content
The technical problems to be solved in the utility model is, can not meet simultaneously efficiently for above-mentioned inverse-excitation type switch power-supply
Rate, the problem of quickly starting, there is provided a kind of start-up circuit and inverse-excitation type switch power-supply.
The technical scheme that the utility model solves above-mentioned technical problem is to provide a kind of start-up circuit, including first starts
Unit, the second start unit and startup reset unit, and the equivalent resistance of first start unit is less than second and started
The equivalent resistance of unit；Wherein：The input of first start unit and the second start unit is connected respectively to power supply electricity
Source；The output end for starting reset unit and being connected to the second start unit, and the startup reset unit is in control terminal voltage
To be turned on during the second predeterminated voltage；The output end of second start unit is connected to the control terminal of first start unit simultaneously
The first predeterminated voltage is exported in the startup reset unit cut-off, output the 3rd is default in the startup reset unit conducting
Voltage, the 3rd predeterminated voltage are less than the first predeterminated voltage；First start unit reaches the first default electricity in control terminal
Exported during pressure by output end and start voltage.
In start-up circuit described in the utility model, first start unit includes first resistor, first switch pipe
And first electric capacity, one end of the first resistor is connected to power supply, the other end is connected to via the first switch pipe
First electric capacity；The control terminal of the first switch pipe forms the control terminal of first start unit；First electric capacity and
The tie point of one switching tube forms the output end of first start unit.
In start-up circuit described in the utility model, second start unit include the second resistance that is connected in series and
Voltage-regulator diode, and the tie point of the second resistance and the voltage-regulator diode forms the output of second start unit
End, the other end of the second resistance form the input of second start unit；The resistance value of the second resistance is more than
The resistance value of first resistor.
In start-up circuit described in the utility model, the startup reset unit includes second switch pipe, 3rd resistor
And second electric capacity, one end connection control terminal for starting reset unit of the 3rd resistor, the other end are connected respectively to
The control terminal of second electric capacity and second switch pipe, one end of the second switch pipe be connected to the control terminal of the first start unit,
The other end connects the 3rd predeterminated voltage.
In start-up circuit described in the utility model, the startup reset unit includes diode, and the diode
Anode connection it is described start the control terminal of reset unit, negative electrode connects the 3rd resistor.
In start-up circuit described in the utility model, the startup reset unit includes the 3rd electric capacity, the 3rd electricity
One end of appearance connects the anode of the diode, the other end connects the 3rd predeterminated voltage.
In start-up circuit described in the utility model, the conducting that first predeterminated voltage is more than first switch pipe is high
Pressure, the 3rd predeterminated voltage are less than the conducting voltage of the first switch pipe.
The utility model also provides a kind of inverse-excitation type switch power-supply, including control chip and transformer, it is characterised in that：Institute
Stating inverse-excitation type switch power-supply also includes start-up circuit as described above, and the output end of second start unit be connected to it is described
The power pins of control chip；The reference signal output pin of the control chip is connected to the control terminal for starting reset unit.
In inverse-excitation type switch power-supply described in the utility model, the transformer includes accessory power supply winding, and described
The output end of accessory power supply winding is connected to the power pins of the control chip.
Start-up circuit and inverse-excitation type switch power-supply of the present utility model have the advantages that：By with compared with low resistance
The first start unit output of value starts voltage, and by the second start unit and starts reset unit by the after start completion
One start unit bypasses, and can not only realize quick startup, and can reduce the power consumption of whole start-up circuit.
Brief description of the drawings
Fig. 1 is the circuit diagram of existing inverse-excitation type switch power-supply；
Fig. 2 is the schematic diagram of the utility model start-up circuit；
Fig. 3 is the schematic diagram of the utility model inverse-excitation type switch power-supply embodiment.
Embodiment
In order that the purpose of this utility model, technical scheme and advantage are more clearly understood, below in conjunction with accompanying drawing and implementation
Example, the utility model is further elaborated.It should be appreciated that specific embodiment described herein is only explaining
The utility model, it is not used to limit the utility model.
As shown in Fig. 2 being the schematic diagram of the utility model start-up circuit embodiment, the start-up circuit can be applied to inverse-excitation type
Switching Power Supply, and the control chip into inverse-excitation type switch power-supply provides and starts voltage.Start-up circuit in the present embodiment includes
First start unit 21, the second start unit 22 and startup reset unit 23, and the equivalent resistance of the first start unit 21
More than the equivalent resistance of the second start unit 22；Wherein：The input of first start unit 21 and the second start unit 22 point
Power supply (such as positive electrode of dc source) is not connected to.Start reset unit 23 and be connected to the defeated of the second start unit 22
Go out end, and (control terminal of the startup reset unit 23 is connected to inverse-excitation type switch power-supply to the startup reset unit 23 in control terminal
In control chip) voltage turned on when being the second predeterminated voltage (such as high level)；The output end connection of second start unit 22
To the first start unit 21 control terminal and start reset unit 23 end when export the first predeterminated voltage (i.e. according to input
Power supply voltage produce the first predeterminated voltage, and exported by output end), export the when starting reset unit 23 and turning on
Three predeterminated voltages, wherein the 3rd predeterminated voltage is less than the first predeterminated voltage.It is pre- that first start unit 21 in control terminal reaches first
If exported during voltage by output end and start voltage (the startup voltage is more than the first predeterminated voltage), i.e., according to the power supply of input
Supply voltage, which produces, starts voltage, and is exported by output end.First start unit 21 is when control terminal is three predeterminated voltage
No current, startup voltage is not exported.
Because the first predeterminated voltage of the second start unit 22 output is less than the startup voltage of the first start unit 21 output,
Therefore the quick output for starting voltage can be realized；Simultaneously because the equivalent resistance of the first start unit 21, which is less than second, starts list
The equivalent resistance of member 22, therefore after starting reset unit 23 and turning on (i.e. during control chip normal work), power supply stream
Through the second start unit 22, and the first start unit 21 is no longer flow through, electric current is smaller in whole start-up circuit, is opened so as to reduce
The overall power of dynamic circuit.
With reference to such as Fig. 3, above-mentioned first start unit 21 includes first resistor R1, first switch pipe Q1 and the first electric capacity
C1, first resistor R1 one end are connected to power supply (i.e. Vin positive pole), the other end is connected to via first switch pipe Q1
One electric capacity C1；First switch pipe Q1 control terminal forms the control terminal of the first start unit 21；First electric capacity C1 and first switch
Pipe Q1 tie point forms the output end of the first start unit 21.When first switch pipe Q1 is turned on, first resistor R1 is first
Electric capacity C1 charges, and when the first electric capacity C1 voltage reaches and starts voltage, is connected to the control of the output end of the first start unit 21
Coremaking piece can start.Above-mentioned first switch pipe Q1 can use MOSFET (Metal-Oxide-Semiconductor Field-
Effect Transistor, metal-oxide half field effect transistor), it can also use triode, IGBT (Insulated Gate
Bipolar Transistor, insulated gate bipolar transistor) etc..
Above-mentioned second start unit 22 includes the second resistance R2 and voltage-regulator diode D1 being connected in series, and second resistance R2
The output end of the second start unit 22 is formed with voltage-regulator diode D1 tie point, the second resistance R2 other end forms second and opened
Moving cell R1 input；Second resistance R2 resistance value is more than first resistor R1 resistance value.Second resistance R2 and voltage stabilizing two
Pole pipe D1 can provide conducting voltage for the first switch pipe Q1 of the first start unit 21, be opened so as to which the first start unit 21 is exportable
Voltage is moved to control chip.
Starting reset unit 23 includes second switch pipe Q2,3rd resistor R3 and the second electric capacity C2,3rd resistor R3's
(control terminal of the startup reset unit 23 may be connected to the reference of control chip to the control terminal of one end connection startup reset unit 23
Voltage output pin), the other end be connected respectively to the second electric capacity C2 and second switch pipe Q2 control terminal, second switch pipe Q2's
One end is connected to the control terminal of the first start unit 21, the other end be connected to the 3rd predeterminated voltage terminals (such as
Power supply Vin negative pole).Above-mentioned second switch pipe Q2 can use MOSFET (Metal-Oxide-Semiconductor
Field-Effect Transistor, metal-oxide half field effect transistor), it can also use triode, IGBT (Insulated Gate
Bipolar Transistor, insulated gate bipolar transistor) etc..
In above-mentioned start-up circuit, (now control chip is not actuated, and second switch pipe Q2 is because of control after electricity on power supply
Terminal voltage processed is not up to conducting voltage and ended), voltage-regulator diode D1 keeps certain voltage, and (i.e. the first predeterminated voltage, this first
Predeterminated voltage be more than or equal to first switch pipe Q1 conducting voltage) so that first switch pipe Q1 turn on, first resistor R1 via
First switch pipe Q1 charges rapidly for the first electric capacity C1；After the first electric capacity C1 voltage reaches certain value (starting voltage),
Control chip is started working, its reference voltage output pin (i.e. VREFPin) output high level, second switch pipe Q2 conductings, and will
To the 3rd predeterminated voltage, (the 3rd predeterminated voltage is less than first switch pipe Q1 conducting to first switch Q1 control terminal voltage pull-down
Voltage) so that first switch pipe Q1 ends；Second resistance R2, second switch pipe Q2 bypass first resistor R1 afterwards, the first electricity
Resistance R1 no longer produces loss.Because second resistance R2 resistance value is more than first resistor R1 resistance value, therefore whole startup electricity
The loss on road substantially reduces.
In addition, to prevent from flowing backwards, above-mentioned startup reset unit 23 may also include diode D2, and diode D2 anode connects
Meet the control terminal for starting reset unit 23, negative electrode connection 3rd resistor R3.
Above-mentioned startup reset unit 23 may also include the 3rd electric capacity C3, the sun of the 3rd electric capacity C3 one end connection diode
Pole, the other end are connected to the terminals (or connection reference ground) with the 3rd predeterminated voltage.By the 3rd electric capacity C3, electricity can be filtered out
Interference signal in road, improve the stability of circuit.
As shown in figure 3, the utility model also provides a kind of inverse-excitation type switch power-supply, including control chip, transformer and
Above-mentioned start-up circuit, and the output end of the first start unit 21 is connected to the power pins V of control chipCC；Control chip
Reference signal output pin VREFIt is connected to the control terminal for starting reset unit 23.
Above-mentioned transformer T1 includes accessory power supply winding, and the output end of the accessory power supply winding is connected to control chip
Power pins VCC.After control chip startup, pin VG outputs high pressure turns on the 3rd switching tube Q3, so as to be produced in transformer T1
Raw flux change, pin V of the accessory power supply winding to control chip power supplyCCExport supply voltage.
It is described above, the only preferable embodiment of the utility model, but the scope of protection of the utility model is not
This is confined to, any one skilled in the art can readily occur in the technical scope that the utility model discloses
Change or replacement, should all cover within the scope of protection of the utility model.Therefore, the scope of protection of the utility model should
It is defined by scope of the claims.
Claims (9)
- A kind of 1. start-up circuit, it is characterised in that：Including the first start unit, the second start unit and start reset unit, And the equivalent resistance of first start unit is less than the equivalent resistance of the second start unit；Wherein：Described first starts The input of unit and the second start unit is connected respectively to power supply；The startup reset unit is connected to the second startup list The output end of member, and the startup reset unit turns on when it is the second predeterminated voltage to control terminal voltage；Described second starts list The output end of member be connected to the control terminal of first start unit and in the startup reset unit cut-off output it is first pre- If voltage, exporting the 3rd predeterminated voltage in the startup reset unit conducting, it is default that the 3rd predeterminated voltage is less than first Voltage；First start unit is exported when control terminal reaches the first predeterminated voltage by output end starts voltage.
- 2. start-up circuit according to claim 1, it is characterised in that：First start unit includes first resistor, the One switching tube and the first electric capacity, one end of the first resistor are connected to the power supply, the other end via described first Switching tube is connected to the first electric capacity；The control terminal of the first switch pipe forms the control terminal of first start unit；It is described The tie point of first electric capacity and first switch pipe forms the output end of first start unit.
- 3. start-up circuit according to claim 2, it is characterised in that：Second start unit includes the be connected in series Two resistance and voltage-regulator diode, and the second resistance and the tie point of the voltage-regulator diode form second start unit Output end, the other end of the second resistance form the input of second start unit；The resistance of the second resistance Resistance value of the value more than first resistor.
- 4. start-up circuit according to claim 1, it is characterised in that：It is described startup reset unit include second switch pipe, 3rd resistor and the second electric capacity, one end connection control terminal for starting reset unit of the 3rd resistor, the other end point The control terminal of the second electric capacity and second switch pipe is not connected to, and one end of the second switch pipe is connected to the first start unit Control terminal, the other end are connected to the terminals with the 3rd predeterminated voltage.
- 5. start-up circuit according to claim 4, it is characterised in that：The startup reset unit includes diode, and institute State the anode connection control terminal for starting reset unit of diode, negative electrode connects the 3rd resistor.
- 6. start-up circuit according to claim 5, it is characterised in that：The startup reset unit includes the 3rd electric capacity, institute Anode, the other end for stating one end connection diode of the 3rd electric capacity are connected to the terminals with the 3rd predeterminated voltage.
- 7. start-up circuit according to claim 2, it is characterised in that：First predeterminated voltage is more than first switch pipe Turn on high pressure, the 3rd predeterminated voltage is less than the conducting voltage of the first switch pipe.
- 8. a kind of inverse-excitation type switch power-supply, including control chip and transformer, it is characterised in that：The inverse-excitation type switch power-supply is also Output end including the start-up circuit as any one of claim 1-7, and first start unit is connected to described The power pins of control chip；The reference signal output pin of the control chip is connected to the control terminal for starting reset unit.
- 9. inverse-excitation type switch power-supply according to claim 8, it is characterised in that：The transformer include accessory power supply around Group, and the output end of the accessory power supply winding is connected to the power pins of the control chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720805835.3U CN207069897U (en) | 2017-07-05 | 2017-07-05 | Start-up circuit and inverse-excitation type switch power-supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720805835.3U CN207069897U (en) | 2017-07-05 | 2017-07-05 | Start-up circuit and inverse-excitation type switch power-supply |
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| Publication Number | Publication Date |
|---|---|
| CN207069897U true CN207069897U (en) | 2018-03-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720805835.3U Active CN207069897U (en) | 2017-07-05 | 2017-07-05 | Start-up circuit and inverse-excitation type switch power-supply |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111697809A (en) * | 2020-07-20 | 2020-09-22 | 阳光电源股份有限公司 | Switching power supply and control method thereof |
| CN111697807A (en) * | 2020-06-29 | 2020-09-22 | 科华恒盛股份有限公司 | Switching power supply circuit and converter |
-
2017
- 2017-07-05 CN CN201720805835.3U patent/CN207069897U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111697807A (en) * | 2020-06-29 | 2020-09-22 | 科华恒盛股份有限公司 | Switching power supply circuit and converter |
| CN111697807B (en) * | 2020-06-29 | 2022-03-11 | 科华恒盛股份有限公司 | Switching power supply circuit and converter |
| CN111697809A (en) * | 2020-07-20 | 2020-09-22 | 阳光电源股份有限公司 | Switching power supply and control method thereof |
| CN111697809B (en) * | 2020-07-20 | 2022-04-08 | 阳光电源股份有限公司 | Switching power supply and control method thereof |
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