CN204304789U - Flyback power supply - Google Patents

Flyback power supply Download PDF

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Publication number
CN204304789U
CN204304789U CN201420839565.4U CN201420839565U CN204304789U CN 204304789 U CN204304789 U CN 204304789U CN 201420839565 U CN201420839565 U CN 201420839565U CN 204304789 U CN204304789 U CN 204304789U
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CN
China
Prior art keywords
circuit
transformer
power supply
switching tube
driver
Prior art date
Application number
CN201420839565.4U
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Chinese (zh)
Inventor
张东卫
Original Assignee
东莞市奥源电子科技有限公司
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Application filed by 东莞市奥源电子科技有限公司 filed Critical 东莞市奥源电子科技有限公司
Priority to CN201420839565.4U priority Critical patent/CN204304789U/en
Application granted granted Critical
Publication of CN204304789U publication Critical patent/CN204304789U/en

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Abstract

Flyback power supply, relate to power technique fields, comprise start-up circuit, transformer T1, the driver U1 of switching tube Q1 and the break-make for control switch pipe Q1, the armature winding of transformer T1 is connected between input power and ground after connecting with switching tube Q1, the secondary winding of transformer T1 externally provides power supply to export, start-up circuit is from described input power power taking and provide starting resistor to driver U1, transformer T1 is also provided with auxiliary winding, this auxiliary winding obtains electric backward driver U1 and powers, also comprise energy-saving circuit, the auxiliary winding of transformer T1 obtain electric after, energy-saving circuit is triggered thus cuts off the circuit that start-up circuit powers to driver U1.

Description

Flyback power supply

Technical field

The invention relates to power technique fields, is specifically related to a kind of flyback power supply.

Background technology

The principle of flyback power supply as shown in Figure 2, IN holds input DC power, side a and b is output, when switching tube Q1 conducting, the induced voltage of transformer T1 armature winding is upper just lower negative, rectifier diode D4 is in cut-off state, storage power in transformer T1 armature winding, when switching tube Q1 ends, the energy stored in transformer T1 armature winding is by exporting to load after secondary winding and rectifier diode D4 rectification and electric capacity C9 filtering, electric capacity C9 completes charging simultaneously, with switch Q1 again conducting time maintained to the output of load by electric discharge.Controller U1 sends the pwm signal with certain duty ratio to the control end of switch Q1, controls the output to load by this.

In practical application, transformer T1 is also provided with auxiliary winding usually, powers to maintain controller U1 work by this auxiliary winding to controller U1; but; time controller U1 does not start, flyback power supply does not enter operating state, and the auxiliary winding of transformer T1 does not also just export.In order to start-up connector U1, a start-up circuit can only be set up again, start-up circuit usually from the input power taking of flyback power supply, like this input of flyback power supply obtain electric after, start-up circuit just can provide a starting resistor with start-up connector U1 to controller U1.After controller U1 starts, its control switch pipe Q1 break-make, flyback power supply also just enters operating state, the auxiliary winding of transformer T1 thereupon electric and power to controller U1.Existing flyback power supply, after entering operating state, the auxiliary winding of transformer T1 is taken over after start-up circuit powers to controller U1, and start-up circuit still keeps conducting and continuous firing, thus causes unnecessary loss.

Summary of the invention

For the above-mentioned technical problem that prior art exists, the invention provides a kind of flyback power supply, and it can reduce the wastage, energy savings.

For achieving the above object, the invention provides following technical scheme.

Flyback power supply, comprise start-up circuit, transformer T1, the driver U1 of switching tube Q1 and the break-make for control switch pipe Q1, the armature winding of transformer T1 is connected between input power and ground after connecting with switching tube Q1, the secondary winding of transformer T1 externally provides power supply to export, start-up circuit is from described input power power taking and provide starting resistor to driver U1, transformer T1 is also provided with auxiliary winding, this auxiliary winding obtains electric backward driver U1 and powers, also comprise energy-saving circuit, the auxiliary winding of transformer T1 obtain electric after, energy-saving circuit is triggered thus cuts off the circuit that start-up circuit powers to driver U1.

Wherein, start-up circuit comprises divider resistance R8, divider resistance R9 and switching tube Q2, divider resistance R8 and divider resistance R9 is connected between described input power and ground after connecting, switching tube Q2 control end connects the contact of divider resistance R8 and divider resistance R9, and two controlled conduction terminal connect described input power and driver U1 respectively.

Wherein, switching tube Q2 is NPN type triode, energy-saving circuit is provided with switching tube Q3, the control end of two controlled conduction terminal difference connecting valve pipe Q2 of switching tube Q3 and ground, the auxiliary winding of transformer T1 obtain electric after, switching tube Q3 is triggered and conducting, thus makes the control end ground connection of switching tube Q2, and switching tube Q2 ends thus.

Wherein, start-up circuit is also provided with current-limiting resistance, and switching tube Q2 connects described input power via this current-limiting resistance.

Wherein, also comprise auxiliary power supply circuit, the auxiliary winding of transformer T1 is powered to driver U1 via auxiliary power supply circuit, auxiliary power supply circuit is provided with rectifier diode D2 and storage capacitor C4, one end of the auxiliary winding of rectifier diode D2 positive pole connection transformer T1, negative pole connects driver U1, and storage capacitor C4 one end connects the negative pole of rectifier diode D2, other end ground connection.

Wherein, also comprise mains rectifier, mains rectifier will export described input power behind commercial power rectification.

Wherein, also comprise leadage circuit, leadage circuit comprises diode D1, resistance R5, resistance R7 and electric capacity C2, diode D1 and resistance R5 is connected to the two ends of the armature winding of transformer T1 after connecting, resistance R7 and electric capacity C2 is connected between the contact of diode D1 and resistance R5 and described input power after connecting.

Wherein, also comprise electric capacity CY1, electric capacity CY1 is connected across between the secondary winding of transformer T1 and auxiliary winding.

The beneficial effect of the invention is: set up an energy-saving circuit, it is controlled by the auxiliary winding of transformer T1, after the flyback power supply of the invention enters operating state, the auxiliary winding of transformer T1 obtains electric, namely energy-saving circuit is triggered, and cuts off the circuit that start-up circuit is powered to driver U1 thus, start-up circuit is quit work after power supply enters operating state, thus reduce the wastage, energy savings.

Accompanying drawing explanation

Fig. 1 is the circuit theory diagrams of the flyback power supply of the invention.

Fig. 2 is the circuit theory diagrams of classical flyback power supply.

Reference numeral comprises: start-up circuit 1, energy-saving circuit 2, auxiliary power supply circuit 3, leadage circuit 4.

Embodiment

Below in conjunction with specific embodiment, the invention is elaborated.

Figure 1 shows that the flyback power supply of the present embodiment, comprise mains rectifier BD1, transformer T1, switching tube Q1, driver U1, rectifier diode D4, electric capacity C9, start-up circuit 1, energy-saving circuit 2, auxiliary power supply circuit 3 and leadage circuit 4, mains rectifier BD1 carries out rectification to civil power, and its DC power supply exported is as the input power of the flyback power supply of the present embodiment.

After civil power energising, current-limiting resistance R1, R2 and divider resistance R8, R9 form loop, R1, R2, R8 and R9 tetra-resistance carry out dividing potential drop to the voltage of described input power, the base stage of NPN type triode Q2 is high level, triode Q2 conducting, described input power provides starting resistor via current-limiting resistance R1, R2 and triode Q2 to the power vd D pin of driver U1, driver U1 is activated thus and to the grid output pwm signal of switching tube Q1 to control its break-make, the flyback power supply of the present embodiment enters operating state thus.Since then, the secondary winding of transformer T1 and auxiliary winding all electric, transformer T1 secondary winding exports load via rectifier diode D4 and electric capacity C9 to from A, B end, and auxiliary winding is then powered to maintain driver U1 via auxiliary power supply circuit 3 to the power vd D pin of driver U1 and worked.Auxiliary power supply circuit 3 comprises rectifier diode D2 and storage capacitor C4, driver U1 is supplied after rectification is carried out in the output of rectifier diode D2 to the auxiliary winding of transformer T1, storage capacitor C4 has energy storage and filtering two effect, when the auxiliary winding of transformer T1 exports reverse, rectifier diode D2 ends, and is now powered to driver U1 by storage capacitor C4.

The auxiliary winding of transformer T1 obtain electric after, the base stage of NPN type triode Q3 just saltus step is high level, triode Q3 conducting, thus makes the base earth of triode Q2, and triode Q2 ends thus, the circuit that start-up circuit 1 is powered to driver U1 thus cut-off.

Leadage circuit 4 plays the effect of the leakage inductance of the transformer T1 that releases, and in addition, after civil power power down, leadage circuit 4 also can discharge to the armature winding of transformer T1.Electric capacity CY1 is connected across between the secondary winding of transformer T1 and auxiliary winding, is intended to the signal eliminated between secondary winding and auxiliary winding and scurries into interference mutually, avoid auxiliary winding to affect the output of secondary winding to load.

Finally should be noted that; above embodiment is only in order to illustrate the technical scheme of the invention; but not the restriction to the invention protection range; although done to explain to the invention with reference to preferred embodiment; those of ordinary skill in the art is to be understood that; can modify to the technical scheme of the invention or equivalent replacement, and not depart from essence and the scope of the invention technical scheme.

Claims (8)

1. flyback power supply, comprise start-up circuit, transformer T1, the driver U1 of switching tube Q1 and the break-make for control switch pipe Q1, the armature winding of transformer T1 is connected between input power and ground after connecting with switching tube Q1, the secondary winding of transformer T1 externally provides power supply to export, start-up circuit is from described input power power taking and provide starting resistor to driver U1, transformer T1 is also provided with auxiliary winding, this auxiliary winding obtains electric backward driver U1 and powers, it is characterized in that, also comprise energy-saving circuit, the auxiliary winding of transformer T1 obtain electric after, energy-saving circuit is triggered thus cuts off the circuit that start-up circuit powers to driver U1.
2. flyback power supply according to claim 1, it is characterized in that, start-up circuit comprises divider resistance R8, divider resistance R9 and switching tube Q2, divider resistance R8 and divider resistance R9 is connected between described input power and ground after connecting, switching tube Q2 control end connects the contact of divider resistance R8 and divider resistance R9, and two controlled conduction terminal connect described input power and driver U1 respectively.
3. flyback power supply according to claim 2, it is characterized in that, switching tube Q2 is NPN type triode, energy-saving circuit is provided with switching tube Q3, the controlled conduction terminal of two of switching tube Q3 are the control end of connecting valve pipe Q2 and ground respectively, the auxiliary winding of transformer T1 obtain electric after, switching tube Q3 is triggered and conducting, thus making the control end ground connection of switching tube Q2, switching tube Q2 ends thus.
4. flyback power supply according to claim 2, is characterized in that, start-up circuit is also provided with current-limiting resistance, and switching tube Q2 connects described input power via this current-limiting resistance.
5. flyback power supply according to claim 1, it is characterized in that, also comprise auxiliary power supply circuit, the auxiliary winding of transformer T1 is powered to driver U1 via auxiliary power supply circuit, auxiliary power supply circuit is provided with rectifier diode D2 and storage capacitor C4, one end of the auxiliary winding of rectifier diode D2 positive pole connection transformer T1, and negative pole connects driver U1, storage capacitor C4 one end connects the negative pole of rectifier diode D2, other end ground connection.
6. flyback power supply according to claim 1, is characterized in that, also comprises mains rectifier, and mains rectifier will export described input power behind commercial power rectification.
7. flyback power supply according to claim 1, it is characterized in that, also comprise leadage circuit, leadage circuit comprises diode D1, resistance R5, resistance R7 and electric capacity C2, diode D1 and resistance R5 is connected to the two ends of the armature winding of transformer T1 after connecting, resistance R7 and electric capacity C2 is connected between the contact of diode D1 and resistance R5 and described input power after connecting.
8. flyback power supply according to claim 1, is characterized in that, also comprises electric capacity CY1, and electric capacity CY1 is connected across between the secondary winding of transformer T1 and auxiliary winding.
CN201420839565.4U 2014-12-26 2014-12-26 Flyback power supply CN204304789U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201420839565.4U CN204304789U (en) 2014-12-26 2014-12-26 Flyback power supply

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201420839565.4U CN204304789U (en) 2014-12-26 2014-12-26 Flyback power supply

Publications (1)

Publication Number Publication Date
CN204304789U true CN204304789U (en) 2015-04-29

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN201420839565.4U CN204304789U (en) 2014-12-26 2014-12-26 Flyback power supply

Country Status (1)

Country Link
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105680678A (en) * 2016-03-30 2016-06-15 合肥惠科金扬科技有限公司 Discharge circuit and AC power supply device
CN107124104A (en) * 2016-02-25 2017-09-01 株式会社村田制作所 DC/DC conversion equipments
CN107947556A (en) * 2017-12-04 2018-04-20 广州金升阳科技有限公司 A kind of Switching Power Supply start-up circuit

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107124104A (en) * 2016-02-25 2017-09-01 株式会社村田制作所 DC/DC conversion equipments
CN107124104B (en) * 2016-02-25 2020-04-21 株式会社村田制作所 DC/DC converter
CN105680678A (en) * 2016-03-30 2016-06-15 合肥惠科金扬科技有限公司 Discharge circuit and AC power supply device
CN105680678B (en) * 2016-03-30 2019-01-18 合肥惠科金扬科技有限公司 A kind of discharge circuit and AC power supply device
CN107947556A (en) * 2017-12-04 2018-04-20 广州金升阳科技有限公司 A kind of Switching Power Supply start-up circuit

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