CN209913700U - Auxiliary power supply circuit of DCDC converter - Google Patents
Auxiliary power supply circuit of DCDC converter Download PDFInfo
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- CN209913700U CN209913700U CN201920624661.XU CN201920624661U CN209913700U CN 209913700 U CN209913700 U CN 209913700U CN 201920624661 U CN201920624661 U CN 201920624661U CN 209913700 U CN209913700 U CN 209913700U
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Abstract
The utility model provides a DCDC converter auxiliary power supply circuit, DCDC converter auxiliary power supply circuit includes linear supply circuit, auxiliary winding supply circuit, steady voltage forbids the circuit, auxiliary winding supply circuit includes electric capacity C1, the steady voltage forbids the circuit and includes resistance R3 and MOS pipe Q3, when input voltage gets into the circuit, linear supply circuit gives rapidly electric capacity C1 charges, simultaneously linear supply circuit's voltage passes through resistance R3 adds MOS pipe Q3's grid, and will MOS pipe Q3 switches on and gives the PWM chip power supply rapidly, and auxiliary winding produces induced voltage after DCDC converter work, at this moment auxiliary winding supply circuit begins to work, linear supply circuit stop work, the power supply source of PWM chip by linear supply circuit converts auxiliary winding supply circuit into.
Description
Technical Field
The utility model relates to a circuit field especially relates to a DCDC converter auxiliary power supply circuit.
Background
The power supply circuit for the DC/DC converter is generally a linear power supply (including an internal linear power supply carried by a chip), which is used for supplying power to the linear power supply and an auxiliary winding. The linear power supply has the advantages of simple circuit and quick response, but has the defect of large loss. The linear power supply and the auxiliary winding power supply are combined with the advantage of quick response of the linear power supply and the advantage of high power supply efficiency of the auxiliary winding. However, the auxiliary winding voltage varies according to the output voltage variation, and if the DC/DC converter has a TRIM terminal, the auxiliary winding voltage may vary greatly and is not suitable for the supply voltage range of the PWM chip.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problem, the utility model provides a DCDC converter auxiliary power supply circuit.
The utility model discloses a following technical scheme realizes:
the utility model provides a DCDC converter auxiliary power supply circuit, DCDC converter auxiliary power supply circuit includes linear supply circuit, auxiliary winding supply circuit, steady voltage forbids the circuit, auxiliary winding supply circuit includes electric capacity C1, the steady voltage forbids the circuit and includes resistance R3 and MOS pipe Q3, when input voltage gets into the circuit, linear supply circuit gives rapidly electric capacity C1 charges, simultaneously linear supply circuit's voltage passes through resistance R3 adds MOS pipe Q3's grid, and will MOS pipe Q3 switches on and gives the PWM chip power supply rapidly, and auxiliary winding produces induced voltage after DCDC converter work, at this moment auxiliary winding supply circuit begins to work, linear supply circuit stop work, the power supply source of PWM chip by linear supply circuit converts auxiliary winding supply circuit into.
Further, the linear power supply circuit comprises a resistor R1, a voltage regulator tube Z1, a triode Q1 and a triode Q2, an emitter of the triode Q1 is connected with a base of the triode Q2, an emitter of the triode Q2 is connected with the auxiliary winding power supply circuit, collectors of the triode Q2 and the triode Q1 are connected with the resistor R1, one end of the voltage regulator tube Z1 is connected with the resistor R3, the other end of the voltage regulator tube Z1 is grounded, and the voltage of the MOS tube Q3 is obtained from the voltage of the voltage regulator tube Z1.
Further, the auxiliary winding power supply circuit further comprises a diode D1, a coil Ns and a resistor R2, wherein one end of the coil Ns is connected with the resistor R2, the other end of the coil is grounded, one end of the capacitor C1 is connected with the negative electrode of the diode D1, one end of the capacitor C1 is connected with the coil Ns, and the positive electrode of the diode D1 is connected with the resistor R2.
Further, the voltage stabilization prohibiting circuit further comprises a capacitor C2, a diode D2, a voltage regulator tube Z2 and a voltage regulator tube Z3, wherein the anode of the diode D2 is connected with the MOS tube Q3, the voltage regulator tube Z2 and the voltage regulator tube Z3 are connected in series and then connected in parallel with the MOS tube, and the capacitor C2 is grounded.
The utility model has the advantages that:
the utility model provides a DCDC converter auxiliary power supply circuit can also satisfy the requirement that output voltage changes on the basis of keeping the advantage that linear power supply response is fast and auxiliary winding power supply efficiency is high through increasing the linear power supply of one-level on the basis of original linear power supply adds the auxiliary winding power supply, can also realize the forbidden function of auxiliary power supply easily simultaneously and have the advantage of extremely low source current.
Drawings
Fig. 1 is a circuit diagram of the auxiliary power supply circuit of the DCDC converter of the present invention.
Detailed Description
For a more clear and complete description of the technical solution of the present invention, the following description is made with reference to the accompanying drawings.
Referring to fig. 1, the present invention provides an auxiliary power supply circuit for a DCDC converter, which includes a linear power supply circuit 1, an auxiliary winding power supply circuit 2, and a voltage stabilization disable circuit 3, the auxiliary winding power supply circuit 2 comprises a capacitor C1, the voltage stabilizing inhibition circuit 3 comprises a resistor R3 and a MOS transistor Q3, when the input voltage enters the circuit, the linear power supply circuit 1 rapidly charges the capacitor C1, meanwhile, the voltage of the linear power supply circuit 1 is applied to the grid electrode of the MOS transistor Q3 through the resistor R3, and the MOS transistor Q3 is conducted so as to rapidly supply power to the PWM chip, when the DCDC converter is operated, the auxiliary winding generates an induced voltage, at this time, the auxiliary winding power supply circuit 2 starts to operate, the linear power supply circuit 1 stops working, and the power supply source of the PWM chip is converted into the auxiliary winding power supply circuit 2 by the linear power supply circuit 1. The linear power supply circuit 1 comprises a resistor R1, a voltage regulator tube Z1, a triode Q1 and a triode Q2, wherein an emitting electrode of the triode Q1 is connected with a base electrode of the triode Q2, an emitting electrode of the triode Q2 is connected with the auxiliary winding power supply circuit 2, collecting electrodes of the triode Q2 and the triode Q1 are connected with the resistor R1, one end of the voltage regulator tube Z1 is connected with the resistor R3, the other end of the voltage regulator tube Z1 is grounded, and the voltage of the MOS tube Q3 is obtained from the voltage of the voltage regulator tube Z1. The auxiliary winding power supply circuit 2 further comprises a diode D1, a coil Ns and a resistor R2, wherein one end of the coil Ns is connected with the resistor R2, the other end of the coil is grounded, one end of the capacitor C1 is connected with the negative electrode of the diode D1, one end of the capacitor C1 is connected with the coil Ns, and the positive electrode of the diode D1 is connected with the resistor R2. The voltage stabilizing prohibition circuit further comprises a capacitor C2, a diode D2, a voltage stabilizing tube Z2 and a voltage stabilizing tube Z3, wherein the anode of the diode D2 is connected with the MOS tube Q3, the voltage stabilizing tube Z2 and the voltage stabilizing tube Z3 are connected in series and then connected with the MOS tube in parallel, and the capacitor C2 is grounded.
In this embodiment, the linear power supply circuit 1 is connected to the VIN terminal, the negative electrode of the diode D2 of the voltage regulation prohibiting circuit 3 is connected to the INH terminal, when the input voltage is powered on, the linear power supply circuit 1 quickly charges the capacitor C1, and simultaneously the voltage of the voltage regulator tube Z1 is applied to the gate of the MOS tube Q3 through the resistor R3, and turns on the MOS tube Q3, so as to quickly supply power to the PWM chip. When the DC/DC converter works, the auxiliary winding power supply circuit 2 generates induction voltage, the auxiliary winding power supply circuit 2 starts to work at the moment, the linear power supply circuit 1 does not work at the moment due to the fact that the voltage of the auxiliary winding power supply circuit 2 is high, the power supply of a PWM chip comes from the auxiliary winding circuit 2, and therefore loss is reduced. When the TRIM end of the DC/DC converter is adjusted so as to make the output voltage change greatly, the voltage of the coil Ns is taken from the output inductor or from the transformer, so the voltage of the auxiliary winding power supply circuit 2 changes greatly, and the voltage of the gate of the MOS transistor Q3 is taken from the voltage regulator tube Z1, so the voltage of the gate is the voltage of the voltage regulator tube Z1, so the MOS transistor Q3 forms a two-stage linear voltage regulator circuit, so that the output voltage is stabilized at the regulated voltage of the voltage regulator tube Z1 minus the threshold voltage of the turn-on voltage of the MOS transistor Q3, thereby preventing the PWM chip from damaging the chip due to the large voltage change of the auxiliary winding power supply circuit 2. On the other hand, since Q3 is a MOS transistor and no current maintenance is required after gate driving, the resistance of the resistor R3 can be made large, so that a very small source current can be realized by disabling the gate of the MOS transistor Q3, thereby reducing the load of the enable disable circuit.
Of course, the present invention can also have other various embodiments, and based on the embodiments, those skilled in the art can obtain other embodiments without any creative work, and all of them belong to the protection scope of the present invention.
Claims (4)
1. The auxiliary power supply circuit of the DCDC converter is characterized by comprising a linear power supply circuit, an auxiliary winding power supply circuit and a voltage stabilization inhibiting circuit, wherein the auxiliary winding power supply circuit comprises a capacitor C1, the voltage stabilization inhibiting circuit comprises a resistor R3 and a MOS tube Q3, when an input voltage enters the circuit, the linear power supply circuit rapidly charges the capacitor C1, meanwhile, the voltage of the linear power supply circuit is applied to the grid electrode of the MOS tube Q3 through the resistor R3, the MOS tube Q3 is conducted so as to rapidly supply power to a PWM chip, when the auxiliary winding generates an induced voltage after the DCDC converter works, the auxiliary winding power supply circuit starts to work, the linear power supply circuit stops working, and the power supply source of the PWM chip is converted into the auxiliary winding power supply circuit by the linear power supply circuit.
2. The auxiliary power supply circuit of the DCDC converter as claimed in claim 1, wherein said linear power supply circuit comprises a resistor R1, a regulator tube Z1, a transistor Q1 and a transistor Q2, wherein the emitter of said transistor Q1 is connected to the base of said transistor Q2, the emitter of said transistor Q2 is connected to said auxiliary winding power supply circuit, the collectors of said transistor Q2 and said transistor Q1 are both connected to said resistor R1, one end of said regulator tube Z1 is connected to said resistor R3, the other end of said regulator tube Z1 is grounded, and the voltage of said MOS tube Q3 is derived from the voltage of said regulator tube Z1.
3. The auxiliary power supply circuit of the DCDC converter of claim 1, wherein said auxiliary winding power supply circuit further comprises a diode D1, a coil Ns, a resistor R2, one end of said coil Ns is connected to said resistor R2, the other end of said coil is grounded, one end of said capacitor C1 is connected to the cathode of said diode D1, one end of said capacitor C1 is connected to said coil NS, and the anode of said diode D1 is connected to said R2.
4. The auxiliary power supply circuit of the DCDC converter as claimed in claim 1, wherein said voltage regulation prohibiting circuit further comprises a capacitor C2, a diode D2, a voltage regulator tube Z2 and a voltage regulator tube Z3, the anode of said diode D2 is connected with said MOS tube Q3, said voltage regulator tube Z2 and said voltage regulator tube Z3 are connected in series and then connected in parallel with said MOS tube, and said capacitor C2 is grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920624661.XU CN209913700U (en) | 2019-04-30 | 2019-04-30 | Auxiliary power supply circuit of DCDC converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920624661.XU CN209913700U (en) | 2019-04-30 | 2019-04-30 | Auxiliary power supply circuit of DCDC converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209913700U true CN209913700U (en) | 2020-01-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920624661.XU Active CN209913700U (en) | 2019-04-30 | 2019-04-30 | Auxiliary power supply circuit of DCDC converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN209913700U (en) |
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2019
- 2019-04-30 CN CN201920624661.XU patent/CN209913700U/en active Active
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