CN215072141U - Auxiliary power supply circuit of DC input switching power supply - Google Patents
Auxiliary power supply circuit of DC input switching power supply Download PDFInfo
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- CN215072141U CN215072141U CN202122457669.1U CN202122457669U CN215072141U CN 215072141 U CN215072141 U CN 215072141U CN 202122457669 U CN202122457669 U CN 202122457669U CN 215072141 U CN215072141 U CN 215072141U
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Abstract
The utility model discloses an auxiliary power supply circuit of a DC input switch power supply, which comprises a DC input end, a DC output end, a starting power supply circuit, an auxiliary winding power supply circuit and a switching circuit, wherein the input end of the starting power supply circuit is connected with the DC input end, and the output end is connected with the DC output end; the input end of the auxiliary winding power supply circuit is connected with the auxiliary winding of the DC input switching power supply transformer, and the output end of the auxiliary winding power supply circuit is connected with the DC output end; the switching circuit comprises a control switch, the control end of the switching circuit is connected with the auxiliary winding power supply circuit, and the control switch of the switching circuit is connected in series in the starting power supply circuit. The utility model discloses start when switching power supply and accomplish, auxiliary winding supply circuit's output voltage stabilizes the back, can close and start supply circuit, by the independent power supply of auxiliary winding supply circuit, auxiliary power supply source's consumption is less.
Description
Technical Field
The utility model relates to a switching power supply of DC input especially relates to a DC input switching power supply's supplementary power supply circuit.
Background
The normal operation of the switching power supply requires a power supply to power the control chip or other active devices. The control chip of the traditional switching power supply generally has a high-voltage starting pin, and after the starting of the switching power supply, an auxiliary winding of the switching power supply can replace a high-voltage source to supply power to the control chip; or providing an auxiliary source converter alone; if the two modes can not meet the actual requirements, the auxiliary power supply can be obtained by reducing the voltage of the linear voltage stabilizing circuit for the switching power supply with the wide range of DC input, but the auxiliary power supply obtained by reducing the voltage of the linear voltage stabilizing circuit can increase a large amount of power consumption.
SUMMERY OF THE UTILITY MODEL
The to-be-solved technical problem of the utility model is to provide a less DC input switching power supply's of loss auxiliary power supply circuit.
In order to solve the technical problem, the utility model adopts the technical scheme that an auxiliary power supply circuit of a DC input switching power supply comprises a DC input end, a DC output end, a starting power supply circuit, an auxiliary winding power supply circuit and a switching circuit, wherein the input end of the starting power supply circuit is connected with the DC input end, and the output end of the starting power supply circuit is connected with the DC output end; the input end of the auxiliary winding power supply circuit is connected with the auxiliary winding of the DC input switching power supply transformer, and the output end of the auxiliary winding power supply circuit is connected with the DC output end; the switching circuit comprises a control switch, the control end of the switching circuit is connected with the auxiliary winding power supply circuit, and the control switch of the switching circuit is connected in series in the starting power supply circuit.
In the auxiliary power supply circuit, the starting power supply circuit comprises a current-limiting resistor, a first triode, a first pull-up resistor and a first voltage-regulator tube, wherein the first end of the current-limiting resistor is connected with the direct-current input end, and the second end of the current-limiting resistor is connected with the collector electrode of the first triode through the control switch; the emitter of the first triode is connected with the direct current output end, and the first pull-up resistor is connected between the collector and the base of the first triode; the cathode of the first voltage-stabilizing tube is connected with the base electrode of the first triode, and the anode of the first voltage-stabilizing tube is grounded.
In the auxiliary power supply circuit, the auxiliary winding power supply circuit comprises a second diode, a filter circuit, a second triode, a second pull-up resistor and a second voltage regulator tube, wherein the anode of the second diode is connected with the first end of the auxiliary winding, and the second end of the auxiliary winding is grounded; the cathode of the second diode is connected with the collector of the second triode through the filter circuit, the emitter of the second triode is connected with the direct current output end, and the second pull-up resistor is connected between the collector and the base of the second triode; the cathode of the second voltage-stabilizing tube is connected with the base electrode of the second triode, and the anode of the second voltage-stabilizing tube is grounded.
In the auxiliary power supply circuit, the auxiliary winding power supply circuit includes a third diode, an anode of the third diode is connected to an emitter of the second triode, and a cathode of the third diode is connected to the dc output terminal; the switching circuit comprises a third voltage-regulator tube, two voltage-dividing circuits and two MOS tubes, and the control switch is a PNP triode; the emitter of the PNP triode is connected with the second end of the current-limiting resistor, the collector of the PNP triode is connected with the collector of the first triode, and the third pull-up resistor is connected between the emitter and the base of the PNP triode; the first voltage division circuit is connected between the direct current input end and the ground, and the grid of the first MOS tube is connected with the voltage output end of the first voltage division circuit; the source electrode of the first MOS tube is grounded, and the drain electrode of the first MOS tube is connected with the base electrode of the PNP triode; the second voltage-dividing circuit is connected between the anode of the third voltage-stabilizing tube and the ground, the grid of the second MOS tube is connected with the voltage output end of the second voltage-dividing circuit, and the source is grounded; the drain electrode of the second MOS tube is connected with the grid electrode of the first MOS tube.
The auxiliary power supply circuit comprises an output capacitor, and the output capacitor is connected between the direct current output end and the ground.
The utility model discloses start when switching power supply and accomplish, auxiliary winding supply circuit's output voltage stabilizes the back, can close and start supply circuit, by the independent power supply of auxiliary winding supply circuit, auxiliary power supply source's consumption is less.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
Fig. 1 is a circuit diagram of an auxiliary power supply circuit of a DC input switching power supply according to an embodiment of the present invention.
Detailed Description
The structure and the principle of the auxiliary power supply circuit of the DC input switch power supply of the embodiment of the utility model are shown in figure 1, which comprises a DC input end VI, a DC output end VCCA, an auxiliary winding T1 of a DC input switch power supply transformer, a starting power supply circuit, an auxiliary winding power supply circuit and a switching circuit,
the input end of the starting power supply circuit is connected with the direct current input end VI, and the voltage range of the direct current input end VI is 20-60 VDC. The output end is connected with the direct current output end VCCA. The output capacitor C80 is connected between the dc output terminal VCCA and ground.
The starting power supply circuit comprises a current limiting resistor consisting of resistors R6, R7, R29 and R31, a first NPN triode Q11, a first pull-up resistor consisting of resistors R47 and R54 in parallel connection, and a first voltage regulator tube Z10. The first end of the current limiting resistor is connected with the direct current input end VI, and the second end of the current limiting resistor is connected with the collector of the first NPN triode Q11 through a PNP triode Q1 serving as a control switch. An emitter of the first NPN transistor Q11 is connected to the dc output terminal VCCA, and the first pull-up resistor is connected between a collector and a base of the first NPN transistor Q11. The cathode of the first voltage regulator tube Z10 is connected with the base of the first NPN triode Q11, and the anode is grounded GND.
The auxiliary winding power supply circuit comprises a second diode D2, a third diode D3, a filter circuit consisting of resistors R45, R46 and C22, a second NPN triode Q2, a second pull-up resistor R5 and a second voltage regulator tube Z17, wherein the anode of the second diode D2 is connected with the first end of an auxiliary winding T1, and the second end of the auxiliary winding T1 is grounded GND. The cathode of the second diode D2 is connected to the collector of the second NPN transistor Q2 through a filter circuit, the emitter of the second NPN transistor Q2 is connected to the anode of the third diode D3, and the cathode of the third diode D3 is connected to the dc output terminal VCCA. The second pull-up resistor R5 is connected between the collector and the base of the second NPN transistor Q2. The cathode of the second voltage regulator tube Z17 is connected with the base of the second NPN triode Q2, and the anode is grounded GND.
The switching circuit comprises a third voltage-regulator tube Z13, two voltage-dividing circuits, two MOS tubes and a PNP triode Q1 serving as a control switch. The emitter of the PNP triode Q1 is connected with the second end of the current-limiting resistor of the starting power supply circuit, the collector of the PNP triode Q1 is connected with the collector of the first NPN triode Q11 of the starting power supply circuit, and the third pull-up resistor R1 is connected between the emitter and the base of the PNP triode Q1. The first voltage dividing circuit composed of resistors R32 and R33 is connected between the dc input terminal VI and ground, and divides the input VI. The R33 and R32 resistances are 100K Ω and 24K Ω, respectively. The gate of the first MOS transistor Q4 is connected to the voltage output terminal of the first voltage divider circuit (the connection point of the resistors R32 and R33). The source of the first MOS transistor Q4 is grounded GND, and the drain is connected to the base of the PNP transistor Q1 through the resistor R34. A second voltage-dividing circuit composed of resistors R44 and R41 is connected between the anode of the third voltage-stabilizing tube Z13 and the ground, the gate of the second MOS tube Q6 is connected with the voltage output end (the connection point of the resistors R44 and R41) of the second voltage-dividing circuit, and the source is grounded GND. The drain of the second MOS transistor Q6 is connected to the gate of the first MOS transistor Q4.
When the switching power supply is started and electrified, the connection point of the resistor R32 and the resistor R33 obtains a high level of 4-11V to drive the grid electrode of the first MOS transistor Q4; the first MOS transistor Q4 is turned on, and the source of the first MOS transistor Q4 is grounded; resistors R29, R30, R7, R8, R1 and R34 form a current loop with the ground, the voltage of the first end of the resistor R1 is higher than that of the second end, the emitter of the PNP triode Q1 is connected to the first end of the resistor R1, the base is connected to the second end of the resistor R1, and the PNP triode Q1 is conducted. The resistors R29, R30, R7 and R8 are selected from 100 omega and used for limiting current; the resistor R2 is 2.2K omega, and the resistor R34 is 24K omega; the PNP triode Q1 selects BCX 53-16;
the collector of the NPN triode Q11 is connected with the collector of the PNP triode Q1, and the voltage of the collector of the NPN triode Q11 is approximately equal to the input voltage of 20-60 VDC. After the resistors R47 and R54 are connected in parallel, the first end of the resistor is connected to the collector of the NPN triode Q11, the second end of the resistor is connected to the base of the NPN triode Q11, and the base of the NPN triode Q11 is connected to Z10 to the ground. An emitter of the NPN triode Q11 is connected with the anode of the C80 electrolytic capacitor, the cathode of the C80 is grounded, a current loop is formed by the resistors R47, R54 and Z10, the base voltage of the NPN triode Q11 is higher than the collector voltage, and the NPN triode Q11 is conducted; the output voltage charges C80, while the anode of diode D3 is at a low level. The highest voltage of the switching power supply control chip is 20V, the voltage of a direct current output end VCCA is set to be 18V, the resistances of resistors R47 and R54 are 10K omega, a 10V voltage-stabilizing tube is selected for Z10, TIP3IC is selected for Q11, a diode D3 is 4148, and the capacity of an output capacitor C80 is 100uF;
when the voltage of VCCA reaches the starting voltage of the control chip of the switching power supply, the converter of the switching power supply starts to work to obtain the output voltage. When the input voltage is higher, the voltage drop on the starting power supply circuit without devices is dozens of volts, which can generate the loss of a few watts, thereby not only causing the temperature rise of the devices but also wasting energy; therefore, the voltage of the starting power supply circuit can be turned off at the moment, and the energy consumption can be saved by converting the starting power supply circuit into stable auxiliary winding power supply.
The auxiliary winding T1 of the transformer generates a square wave voltage diode D2, resistors R45, R46 and an electrolytic capacitor C22 to form a rectifying and filtering circuit, and the electrolytic capacitor C22 generates a voltage with a variation range of 20-25V; the diode D2 selects ES3G, the resistances of the resistors R45 and R46 are 3.3 omega, and the capacity of the electrolytic capacitor C22 is 47 uF.
One end of the resistor R5 and a collector of the NPN triode Q2 are connected with the anode of the electrolytic capacitor C22, the other end of the resistor R5 is connected with a base of the NPN triode Q2 and a cathode of the diode Z17, an emitter of the NPN triode Q2 is connected with an anode of the diode D3, the working principle of the NPN triode Q2 is the same as that of the NPN triode Q11, and the VCCA is supplied with the rectified linear regulated voltage output by the auxiliary winding T1 and the linear regulated voltage input by the starting power supply circuit. The resistor R5 takes 2.2K ohm, the NPN triode Q2 selects PBSS306NZ, and the Z10 voltage-regulator selects an 18V voltage-regulator.
The start-up supply circuit is turned off after the voltage supplied to the dc output terminal VCCA from the rectified linear regulated voltage outputted from the auxiliary winding T1 is stabilized. The anode of the stabilivolt Z13 is connected in series with a second voltage divider circuit consisting of resistors R44 and R47 to ground. Z13 selects 5.6V voltage regulator tube, R44 resistance 270K omega, R47 resistance 47K omega. When the voltage of the anode of the diode D3 reaches 18V, the voltage of the output end of the second voltage division circuit, that is, the voltage of the gate of the MOS transistor Q6 is 1.8V, the MOS transistor Q6 is turned on, and the source thereof is grounded, and the drain of the MOS transistor Q6 is connected to the gate of the MOS transistor Q4, so that the MOS transistor Q4 is turned off at this time; the PNP triode Q1 is cut off, the start power supply circuit stops working, and the loss is reduced to almost zero. At the moment, the main loss of the auxiliary power supply circuit comes from the loss of the rectified linear voltage stabilization of the auxiliary winding, the loss is small due to small voltage drop, and when the rectified linear voltage stabilization of the auxiliary winding is unstable in a short time, the auxiliary power supply circuit can be switched to start the power supply circuit to supply power, so that the reliability of the auxiliary power supply circuit is improved.
Claims (5)
1. An auxiliary power supply circuit of a DC input switching power supply comprises a direct current input end and a direct current output end, and is characterized by comprising a starting power supply circuit, an auxiliary winding power supply circuit and a switching circuit, wherein the input end of the starting power supply circuit is connected with the direct current input end, and the output end of the starting power supply circuit is connected with the direct current output end; the input end of the auxiliary winding power supply circuit is connected with the auxiliary winding of the DC input switching power supply transformer, and the output end of the auxiliary winding power supply circuit is connected with the DC output end; the switching circuit comprises a control switch, the control end of the switching circuit is connected with the auxiliary winding power supply circuit, and the control switch of the switching circuit is connected in series in the starting power supply circuit.
2. The auxiliary power supply circuit according to claim 1, wherein the startup power supply circuit comprises a current limiting resistor, a first triode, a first pull-up resistor and a first voltage regulator tube, wherein a first end of the current limiting resistor is connected with the direct current input end, and a second end of the current limiting resistor is connected with a collector electrode of the first triode through the control switch; the emitter of the first triode is connected with the direct current output end, and the first pull-up resistor is connected between the collector and the base of the first triode; the cathode of the first voltage-stabilizing tube is connected with the base electrode of the first triode, and the anode of the first voltage-stabilizing tube is grounded.
3. The auxiliary power supply circuit according to claim 2, wherein the auxiliary winding power supply circuit comprises a second diode, a filter circuit, a second triode, a second pull-up resistor and a second voltage regulator tube, wherein the anode of the second diode is connected with the first end of the auxiliary winding, and the second end of the auxiliary winding is grounded; the cathode of the second diode is connected with the collector of the second triode through the filter circuit, the emitter of the second triode is connected with the direct current output end, and the second pull-up resistor is connected between the collector and the base of the second triode; the cathode of the second voltage-stabilizing tube is connected with the base electrode of the second triode, and the anode of the second voltage-stabilizing tube is grounded.
4. An auxiliary power supply circuit as claimed in claim 3, wherein the auxiliary winding power supply circuit includes a third diode, an anode of the third diode is connected to the emitter of the second triode, and a cathode of the third diode is connected to said dc output terminal; the switching circuit comprises a third voltage-regulator tube, two voltage-dividing circuits and two MOS tubes, and the control switch is a PNP triode; the emitter of the PNP triode is connected with the second end of the current-limiting resistor, the collector of the PNP triode is connected with the collector of the first triode, and the third pull-up resistor is connected between the emitter and the base of the PNP triode; the first voltage division circuit is connected between the direct current input end and the ground, and the grid of the first MOS tube is connected with the voltage output end of the first voltage division circuit; the source electrode of the first MOS tube is grounded, and the drain electrode of the first MOS tube is connected with the base electrode of the PNP triode; the second voltage-dividing circuit is connected between the anode of the third voltage-stabilizing tube and the ground, the grid of the second MOS tube is connected with the voltage output end of the second voltage-dividing circuit, and the source is grounded; the drain electrode of the second MOS tube is connected with the grid electrode of the first MOS tube.
5. An auxiliary power supply circuit according to claim 1, including an output capacitor connected between said dc output and ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122457669.1U CN215072141U (en) | 2021-10-13 | 2021-10-13 | Auxiliary power supply circuit of DC input switching power supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122457669.1U CN215072141U (en) | 2021-10-13 | 2021-10-13 | Auxiliary power supply circuit of DC input switching power supply |
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| CN215072141U true CN215072141U (en) | 2021-12-07 |
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| CN202122457669.1U Active CN215072141U (en) | 2021-10-13 | 2021-10-13 | Auxiliary power supply circuit of DC input switching power supply |
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- 2021-10-13 CN CN202122457669.1U patent/CN215072141U/en active Active
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