CN218387275U - Auxiliary power supply circuit of switching power supply - Google Patents
Auxiliary power supply circuit of switching power supply Download PDFInfo
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- CN218387275U CN218387275U CN202222307790.0U CN202222307790U CN218387275U CN 218387275 U CN218387275 U CN 218387275U CN 202222307790 U CN202222307790 U CN 202222307790U CN 218387275 U CN218387275 U CN 218387275U
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Abstract
The utility model discloses an auxiliary power supply circuit of a switching power supply, wherein the collector of a first triode is connected with the cathode of a second diode, and the emitter is connected with the anode of a direct current output end; the collector of the first triode is connected with the base of the first triode through a first driving resistor; the anode of the first diode is connected with the first end of the auxiliary winding of the transformer, and the cathode of the first diode is connected with the anode of the second diode; the first end of the output capacitor is connected with the anode of the direct current output end, the second end of the output capacitor is grounded, and the second end of the auxiliary winding is grounded; the collector of the second triode is connected with the high-voltage direct-current power supply, and the emitter of the second triode is connected with the collector of the first triode; the collector of the second triode is connected with the base of the second triode through a second driving resistor; the collector of the third triode is connected with the base of the second triode, the emitter of the third triode is grounded, and the base is connected with the cathode of the first diode. The utility model discloses a switch tube can adopt the paster triode, reduces filter capacitance's quantity, practices thrift the cost, is favorable to the miniaturization of product.
Description
[ technical field ]
The utility model relates to an auxiliary power supply especially relates to a switching power supply's auxiliary power supply circuit.
[ background art ]
A switching power supply is a power conversion device which is high in frequency and functions to convert one form of electric energy (AC/DC) into a required DC power. The structure of the switching power supply is shown in fig. 1.
The auxiliary power supply of the switching power supply mainly relates to the starting power supply and the continuous power supply of the control chip, and finally the effect of efficient and stable work of the control chip is achieved.
The traditional auxiliary power supply circuit supplies power by utilizing high-voltage starting power supply and auxiliary winding power supply together, and the invention with the application number of CN201210254466.5 discloses an auxiliary power supply of a switching power supply, which has two common working modes, namely a starting mode and a normal working mode. The power-on moment works in a starting mode, namely, an input high-voltage direct-current power supply supplies power to the control and drive part to work after certain current limiting; when the control and drive part works normally, the power transformer generates an alternating magnetic field, and the alternating magnetic field is supplied to the control and drive part for use after the coil rectification filtering and the linear voltage stabilization of the auxiliary power supply, at the moment, the control and drive part works in a normal working mode, and simultaneously, the electronic switch of the high-voltage direct-current power supply is automatically switched off and does not provide electric energy for the control and drive part any more.
The starting module of the invention has the advantages of large size of the used N-MOS and the N-MOS, large quantity of required filter capacitors, large product volume and high cost.
[ summary of the invention ]
The to-be-solved technical problem of the utility model is to provide a switching power supply's auxiliary power supply circuit small, with low costs.
In order to solve the technical problem, the utility model adopts the technical scheme that an auxiliary power supply circuit of a switching power supply comprises a starting circuit, a working circuit and a direct current output end, the switching power supply comprises a high voltage direct current power supply and a power transformer of a main circuit, the working circuit comprises a first triode, a first driving resistor, a first diode, a second diode, a first voltage regulator tube, an output capacitor and an auxiliary winding of the power transformer; the starting circuit comprises a second triode, a second driving resistor, a second voltage-regulator tube and a third triode; the collector of the first triode is connected with the cathode of the second diode, and the emitter of the first triode is connected with the anode of the direct current output end; the collector of the first triode is connected with the base of the first triode and the cathode of the first voltage-regulator tube through a first driving resistor, and the anode of the first voltage-regulator tube is grounded; the anode of the first diode is connected with the first end of the auxiliary winding, and the cathode of the first diode is connected with the anode of the second diode; the first end of the output capacitor is connected with the anode of the direct current output end, the second end of the output capacitor is grounded, and the second end of the auxiliary winding is grounded; the collector of the second triode is connected with the high-voltage direct-current power supply, and the emitter of the second triode is connected with the collector of the first triode; the collector of the second triode is connected with the base of the second triode and the cathode of a second voltage-regulator tube through a second driving resistor, and the anode of the second voltage-regulator tube is grounded; the collector of the third triode is connected with the base of the second triode, the emitter of the third triode is grounded, and the base is connected with the cathode of the first diode.
In the above auxiliary power supply circuit, the starting circuit includes a third diode, an anode of the third diode is connected to the high voltage dc power supply, and a cathode of the third diode is connected to a collector of the second triode.
In the auxiliary power supply circuit, the starting circuit comprises a current-limiting resistor and a pull-down resistor, and the current-limiting resistor is connected with the base of the third triode and the cathode of the first diode; the base electrode of the third triode is grounded through a pull-down resistor.
In the above auxiliary power supply circuit, the operating circuit includes two energy storage capacitors, the first energy storage capacitor is connected between the cathode of the first diode and the ground, and the second energy storage capacitor is connected between the cathode of the second diode and the ground.
In the auxiliary power supply circuit, the first triode, the second triode and the third triode are patch triodes.
The utility model discloses switch tube among the auxiliary power supply circuit can adopt the paster triode, needs filter capacitance's small in quantity, can practice thrift the cost to be favorable to the product miniaturization.
[ description of the drawings ]
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
FIG. 1 is a circuit block diagram of a prior art switching power supply auxiliary power supply
Fig. 2 is a circuit diagram of the switching power supply auxiliary power supply according to the embodiment of the present invention.
[ detailed description of the invention ]
The embodiment of the utility model provides a switching power supply's auxiliary power supply circuit's structure and principle are shown as figure 2, including starting circuit, working circuit and DC output end. The switching power supply comprises a high-voltage direct-current power supply and a power transformer of a main circuit,
the working circuit comprises a first triode Q9, a first driving resistor R43, a first diode D26, a second diode D6, a first voltage-regulator tube Z3, an output capacitor CE8, an energy-storage capacitor C158, an energy-storage capacitor C40 and an auxiliary winding T3-B of the power transformer. The starting circuit comprises a third diode D5, a second triode Q19, a second driving resistor R80, a FG voltage regulator Z8 and a third triode Q20.
The collector of the first triode Q9 is connected with the cathode of the second diode D6, and the emitter is connected with the anode VDD of the direct current output end. The collector of the first triode Q9 is connected with the base of the first triode Q9 and the cathode of the first voltage-regulator tube Z3 through the first driving resistor R43, and the anode of the first voltage-regulator tube Z3 is grounded. The anode of the first diode D26 is connected to the first end of the auxiliary winding T3-B, and the cathode of the first diode D26 is connected to the anode of the second diode D6. The first end of the output capacitor CE8 is connected with the anode VDD of the DC output end, the second end is grounded, and the second end of the auxiliary winding T3-B is grounded. The first energy storage capacitor C158 is connected between the cathode of the first diode D26 and ground, and the second energy storage capacitor C40 is connected between the cathode of the second diode D6 and ground.
The anode of the third diode D5 is connected to the high voltage dc source +28VOUT, and the cathode is connected to the collector of the second transistor Q19. The emitter of the second triode Q19 is connected to the collector of the first triode Q9. The collector of the second triode Q19 is connected with the base of the second triode Q19 and the cathode of the second voltage-regulator tube Z8 through a second driving resistor R80, and the anode of the second voltage-regulator tube Z8 is grounded. The collector of the third triode Q20 is connected with the base of the second triode Q19, the emitter of the third triode Q20 is grounded, and the base of the third triode Q20 is connected with the cathode of the first diode D26 through the current limiting resistor R119 and is grounded through the pull-down resistor.
The first transistor Q9, the second transistor Q19, and the third transistor Q20 are patch transistors.
The embodiment of the utility model provides a switching power supply's auxiliary power supply circuit's working process as follows:
the high level of the high-voltage direct-current power supply +28VOUT is rectified by a third diode D5, a 18V high level stabilized by a 18V voltage stabilizing tube Z8 is supplied to a second triode Q19 through a driving resistor R80, the second triode Q19 is opened, a 12V high level stabilized by a 12V voltage stabilizing tube Z3 is supplied to the base electrode of a first triode Q9 through a driving resistor R43, the triode Q9 is opened, and 12V starting voltage is supplied to a switching power supply control chip through the positive electrode VDD of a direct-current output end. After the control chip is started, the auxiliary winding T3-B of the main circuit power transformer starts to work, and alternating current output by the auxiliary winding T3-B is rectified by the first diode D26 to obtain high voltage of 16V. The high voltage of 16V gives a high level to the base of the third transistor Q20 through the current limiting resistor R119, turning on the third transistor Q20, so that the base level of the second transistor Q19 is changed to a low level, and the second transistor Q19 is turned off. The 16V high level provided by the auxiliary winding is rectified by a second diode D6, a 12V high level stabilized by a 12V voltage stabilizing tube is provided for the base electrode of the first triode Q9 through a driving resistor R43, and the triode Q9 is kept to be continuously opened, so that the auxiliary winding T3-B independently supplies power for the VDD of the control chip, the electrolytic capacitors C158, C40 and CE8 play a role in energy storage, and the stability of the VDD power supply level can be improved.
The utility model discloses above embodiment switching power supply's switch tube adopts the paster triode, needs filter capacitance's small in quantity, can practice thrift the cost to be favorable to the miniaturization of product.
Claims (5)
1. An auxiliary power supply circuit of a switching power supply comprises a starting circuit, a working circuit and a direct current output end, wherein the switching power supply comprises a high-voltage direct current power supply and a power transformer of a main circuit; the starting circuit comprises a second triode, a second driving resistor, a second voltage-regulator tube and a third triode; the collector of the first triode is connected with the cathode of the second diode, and the emitter of the first triode is connected with the anode of the direct current output end; the collector of the first triode is connected with the base of the first triode and the cathode of the first voltage-regulator tube through a first driving resistor, and the anode of the first voltage-regulator tube is grounded; the anode of the first diode is connected with the first end of the auxiliary winding, and the cathode of the first diode is connected with the anode of the second diode; the first end of the output capacitor is connected with the anode of the direct current output end, the second end of the output capacitor is grounded, and the second end of the auxiliary winding is grounded; the collector of the second triode is connected with the high-voltage direct-current power supply, and the emitter of the second triode is connected with the collector of the first triode; the collector of the second triode is connected with the base of the second triode and the cathode of a second voltage-regulator tube through a second driving resistor, and the anode of the second voltage-regulator tube is grounded; the collector of the third triode is connected with the base of the second triode, the emitter of the third triode is grounded, and the base is connected with the cathode of the first diode.
2. The auxiliary power supply circuit as claimed in claim 1, wherein the start-up circuit comprises a third diode, an anode of the third diode is connected to the high voltage dc power supply, and a cathode of the third diode is connected to the collector of the second transistor.
3. The auxiliary power supply circuit according to claim 1, wherein the start-up circuit includes a current-limiting resistor and a pull-down resistor, the current-limiting resistor being connected to a base of the third transistor and a cathode of the first diode; the base electrode of the third triode is grounded through a pull-down resistor.
4. The auxiliary power supply circuit according to claim 1, wherein the operating circuit includes two energy storage capacitors, a first energy storage capacitor is connected between the cathode of the first diode and ground, and a second energy storage capacitor is connected between the cathode of the second diode and ground.
5. The auxiliary power supply circuit as claimed in claim 2, wherein the first transistor, the second transistor and the third transistor are patch transistors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222307790.0U CN218387275U (en) | 2022-08-31 | 2022-08-31 | Auxiliary power supply circuit of switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222307790.0U CN218387275U (en) | 2022-08-31 | 2022-08-31 | Auxiliary power supply circuit of switching power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218387275U true CN218387275U (en) | 2023-01-24 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222307790.0U Active CN218387275U (en) | 2022-08-31 | 2022-08-31 | Auxiliary power supply circuit of switching power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218387275U (en) |
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2022
- 2022-08-31 CN CN202222307790.0U patent/CN218387275U/en active Active
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