CN209930130U - Switch power supply - Google Patents

Abstract

The utility model relates to a switching power supply, include: the protection circuit comprises a three-phase power supply input end, a protection circuit, a first filter circuit, a rectifying circuit, a transformation circuit, a second filter circuit, a direct-current voltage output end and a control circuit, wherein the three-phase power supply input end, the protection circuit, the first filter circuit, the rectifying circuit, the transformation circuit, the second filter circuit and the direct-current voltage output end are arranged on the same PCB; the three-phase power input end is connected with the direct-current voltage output end through a protection circuit, a first filter circuit, a rectification circuit, a transformation circuit and a second filter circuit in sequence. Implement the utility model discloses can reduce EMI among the switching power supply and disturb.

Description

Switch power supply

Technical Field

The utility model relates to a power technical field, more specifically say, relate to a switching power supply.

Background

A switch mode power supply is a high frequency power conversion device, which is one type of power supply. The function is to convert a level voltage into a voltage or current required by the user terminal through different types of architectures. The input of the switching power supply is mostly an ac power supply (e.g., commercial power) or a dc power supply, and the output is mostly equipment requiring a dc power supply, such as a personal computer, and the switching power supply performs voltage and current conversion between the two. The switching power supply is different from a linear power supply, when the switching power supply works, an internal transistor of the switching power supply is frequently switched, if switching current is processed, noise and electromagnetic interference can be generated to influence other equipment, and if the switching power supply is not specially designed, the power factor of the switching power supply can be not high.

For example, in some specific occasions, the communication equipment needs to communicate in the frequency band of 300MHz-450MHz, but the interference frequency band of the switch power supply is usually distributed from 150KHz to 1000MHz, which cannot meet the requirement of the communication equipment. How to reduce the interference frequency band of the switching power supply to reduce the interference to the communication equipment becomes an important problem in the design process of the switching power supply.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model lies in, to the above-mentioned prior art defect of prior art, a switching power supply is provided.

The utility model provides a technical scheme that its technical problem adopted is: a switching power supply is constructed including: the protection circuit comprises a three-phase power supply input end, a protection circuit, a first filter circuit, a rectifying circuit, a transformation circuit, a second filter circuit, a direct-current voltage output end and a control circuit, wherein the three-phase power supply input end, the protection circuit, the first filter circuit, the rectifying circuit, the transformation circuit, the second filter circuit and the direct-current voltage output end are arranged on the same PCB;

the three-phase power input end is connected with the direct-current voltage output end through the protection circuit, the first filter circuit, the rectification circuit, the transformation circuit and the second filter circuit in sequence.

Preferably, the first filter circuit includes a common-mode inductor LF101, a capacitor CX101, a resistor R103, and a resistor R104;

the first end of the common-mode inductor LF101 is connected with an L line of the three-phase power supply input end through the protection circuit, the third end of the common-mode inductor LF101 is connected with an N line of the three-phase power supply input end, the second end of the common-mode inductor LF101 is connected with the first input end of the rectification circuit, and the fourth end of the common-mode inductor LF101 is connected with the second input end of the rectification circuit;

one end of the capacitor CX101 is connected to the first end of the common-mode inductor LF101, and the other end of the capacitor CX101 is connected to the third end of the common-mode inductor LF 101;

the resistor R103 and the resistor R104 are connected in series and then connected in parallel to the capacitor CX 101.

Preferably, the protection circuit comprises a fuse F101, a varistor MOV101 and a thermistor NTC 101;

fuse F101's one end is connected the L line of three-phase power input end, fuse F101's the other end is connected respectively thermistor NTC101 with piezo-resistor MOV101, and the warp thermistor NTC101 connects common mode inductance LF 101's first end and warp piezo-resistor MOV101 connects the N line of three-phase power input end.

Preferably, the common-mode inductor LF101 is a UU9.8 filter common-mode inductor.

Preferably, the second filter circuit comprises a common-mode inductor LF201,

the first end of the common mode inductor LF201 is connected with the positive output end of the voltage transformation circuit, the second end of the common mode inductor LF201 is connected with the positive electrode of the direct current voltage output end, the third end of the common mode inductor LF201 is connected with the negative output end of the voltage transformation circuit, and the fourth end of the common mode inductor LF201 is connected with the negative electrode of the direct current voltage output end.

Preferably, the second filter circuit further comprises a capacitor C207 and a capacitor C212;

one end of the capacitor C207 is connected to the first end of the common mode inductor LF201, the other end of the capacitor C207 is connected to the third end of the common mode inductor LF201, one end of the capacitor C212 is connected to the second end of the common mode inductor LF201, and the other end of the capacitor C212 is connected to the fourth end of the common mode inductor LF 201.

Preferably, the common mode inductor LF201 is a vertical insert common mode inductor of T9 × 5 × 3.

Preferably, the PCB board is a double-sided board including a first surface and a second surface.

Preferably, the transformation circuit comprises a transformer T101, a capacitor C101, a diode D201 and a capacitor C203, and the control circuit comprises a MOS transistor Q101, a resistor R109, a resistor R116, a diode D106 and a capacitor C104; wherein:

the reverse end of the primary coil of the transformer T101 is grounded through the capacitor C101, the in-phase end of the primary coil of the transformer T101 is connected to the drain of the MOS transistor Q101, the source of the MOS transistor Q101 is grounded through the resistor R10, the primary coil of the transformer T101, the capacitor C101, the MOS transistor Q101 and the resistor R109 are arranged adjacent to the first surface of the PCB board, wherein all connections are connected by the shortest routing; and/or

The in-phase end of the secondary coil of the transformer T101 is connected to the anode of the diode D201, and is sequentially connected to the inverting end of the secondary coil of the transformer T101 through the diode D201 and the capacitor C203, the secondary coil of the transformer T101 is disposed adjacent to the first surface of the PCB board of the diode D201 and the capacitor C203, wherein all connections are connected by the shortest routing; and/or

The in-phase end of the power supply coil of the transformer T101 is connected with the resistor R116 and is sequentially grounded through the resistor R116, the diode D106 and the capacitor C104, the reverse-phase end of the power supply coil of the transformer T101 is grounded, the power supply coil of the transformer T101 and the capacitor C104 are arranged in the vicinity of the first surface of the PCB, the resistor R116 and the diode D106 are arranged in the vicinity of the second surface of the PCB and are arranged in the vicinity of the capacitor C104, and all connections are connected through shortest routing.

Preferably, the inverting terminal of the power supply coil of the transformer T101 and the ground pin of the capacitor C101 are grounded at a single point with the PCB.

Implement the utility model discloses a switching power supply has following beneficial effect: EMI interference in the switching power supply can be reduced.

Drawings

The invention will be further explained with reference to the drawings and examples, wherein:

fig. 1 is a logic block diagram of a switching power supply of the present invention;

fig. 2 is a schematic circuit diagram of an embodiment of a switching power supply of the present invention;

fig. 3 is a schematic structural diagram of a first surface of a PCB according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a second surface of a PCB according to an embodiment of the present invention.

Detailed Description

In order to clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 1, a first embodiment of a switching power supply of the present invention includes: the protection circuit comprises a three-phase power supply input end 10, a protection circuit 20, a first filter circuit 30, a rectification circuit 40, a transformation circuit 50, a second filter circuit 60, a direct-current voltage output end and a control circuit 80, wherein the three-phase power supply input end, the protection circuit 20, the first filter circuit 30, the rectification circuit 40, the transformation circuit 50, the second filter circuit 60 and the direct-current voltage output end are arranged on; the three-phase power input terminal 10 is connected with the direct-current voltage output terminal through a protection circuit 20, a first filter circuit 30, a rectification circuit 40, a transformation circuit 50 and a second filter circuit 60 in sequence. Specifically, the three-phase power input 1010 includes an L line and an N line, and the three-phase power is processed by the rectifying circuit 40 and the transforming circuit 50 and then transmitted to the inside of the device to supply power to the device. The first filter circuit 30 is provided to reduce interference in various frequency bands generated when a voltage processing circuit such as a rectifier circuit 40 and a transformer circuit 50 is operated in the switching power supply. The second filter circuit 60 is arranged to filter low frequency interference, where the low frequency interference and the high frequency interference are opposite, the low frequency interference may be frequency interference in the range of 150KHz to 30MHz, and the high frequency interference may be frequency interference higher than 30 MHz. The control circuit 8090 is connected to the transforming circuit 50 to control the output power during the transforming process. Meanwhile, a protection circuit 20 is provided at the three-phase power input terminal 10 to prevent damage to the internal circuit when the voltage is excessive.

Optionally, as in the embodiment shown in fig. 2, the first filter circuit 30 includes a common-mode inductor LF101, a capacitor CX101, a resistor R103, and a resistor R104; the first end of the common-mode inductor LF101 is connected with the L line of the three-phase power input end 10 through the protection circuit 20, the third end of the common-mode inductor LF101 is connected with the N line of the three-phase power input end 10, the second end of the common-mode inductor LF101 is connected with the first input end of the rectification circuit 40, and the fourth end of the common-mode inductor LF101 is connected with the second input end of the rectification circuit 40; one end of the capacitor CX101 is connected to the first end of the common-mode inductor LF101, and the other end of the capacitor CX101 is connected to the third end of the common-mode inductor LF 101; the resistor R103 and the resistor R104 are connected in series and then connected in parallel to the capacitor CX 101. Specifically, the rectifying circuit 40 may be a rectifier bridge BD101, a filter circuit formed by the common-mode inductor LF101, the capacitor CX101, the resistor R103, and the resistor R104, and mainly functions to filter out common-mode interference in the circuit, where the common-mode interference is mainly concentrated in 150KHz to 30 MHz.

Further, on the above basis, the common-mode inductor LF101 may be selected as the UU9.8 filter common-mode inductor. Of course, in other embodiments, common mode inductors of other specifications may be used for filtering.

Optionally, the protection circuit 20 includes a fuse F101, a voltage dependent resistor MOV101 and a thermistor NTC 101; one end of the fuse F101 is connected to the L line of the three-phase power input terminal 10, and the other end of the fuse F101 is respectively connected to the thermistor NTC101 and the varistor MOV101, and is connected to the first end of the common mode inductor LF101 through the thermistor NTC101 and is connected to the N line of the three-phase power input terminal 10 through the varistor MOV 101. Specifically, the protection circuit 20 connected to the three-phase power input terminal 10 may include a fuse F101, and the fuse F101 prevents the L-line input voltage of the three-phase power input terminal 10 from being too high to damage the circuit at the rear end thereof. The power supply can also comprise a voltage dependent resistor MOV101, wherein the voltage dependent resistor is connected between the L line and the N line of the three-phase power supply input end 10 and mainly used for preventing the damage of the instantaneous high current generated by lightning stroke to the following circuit, and the thermistor NTC101 is used for limiting the current and avoiding the loss caused by the over-high or over-high current in the starting process of the switching power supply. It is understood that the protection circuit 20 can be configured in any way, and the specification thereof can be selected according to the actual requirement.

Optionally, the second filter circuit 60 includes a common mode inductor LF201, a first end of the common mode inductor LF201 is connected to the positive output end of the transformer circuit 50, a second end of the common mode inductor LF201 is connected to the positive electrode of the dc voltage output end 70, a third end of the common mode inductor LF201 is connected to the negative output end of the transformer circuit 50, and a fourth end of the common mode inductor LF201 is connected to the negative electrode of the dc voltage output end 70. The dc output after passing through the transformer circuit 50 includes a positive output terminal and a negative output terminal, and generally, the transformer circuit 50 may include a transformer, in which the in-phase terminal of the transformer output terminal outputs a positive voltage, and the out-phase terminal of the transformer output terminal outputs a negative voltage, corresponding to the positive output terminal, and the negative output terminal. The dc voltage output 70 includes a positive terminal corresponding to the positive output terminal of the transformer circuit 50 and a negative terminal corresponding to the negative output terminal of the transformer circuit 50. The common mode inductor LF201 is connected between the positive output end and the negative output end of the transformer circuit 50 and the positive electrode and the negative electrode of the dc voltage output end 70, so as to realize high-frequency common mode interference in the power supply processing circuit. In this embodiment, the common mode inductance LF201 may employ a vertical plug-in common mode inductance of T9 × 5 × 3.

Further, the second filter circuit 60 further includes a capacitor C207 and a capacitor C212; one end of the capacitor C207 is connected to the first end of the common mode inductor LF201, the other end of the capacitor C207 is connected to the third end of the common mode inductor LF201, one end of the capacitor C212 is connected to the second end of the common mode inductor LF201, and the other end of the capacitor C212 is connected to the fourth end of the common mode inductor LF 201. Specifically, in order to improve the filtering of the common mode inductor LF201 to the high frequency interference, the common mode inductor LF 207 may cooperate with the capacitor C212 to enhance the filtering effect.

Alternatively, as shown in fig. 3-4, the PCB board is a double-sided board including a first surface and a second surface. Specifically, the PCB board that switching power supply chooseed for use can be the double-sided board of two-sided cloth board, and wherein first surface and second surface equipartition have the device, and its device is connected through the wiring layer in the middle of.

Optionally, the voltage transformation circuit 50 includes a transformer T101, a capacitor C101, a diode D201 and a capacitor C203, and the control circuit 80 includes a MOS transistor Q101, a resistor R109, a resistor R116, a diode D106 and a capacitor C104; wherein: in one embodiment, the reverse terminal 6 of the primary winding T5 of the transformer T101 is grounded via the capacitor C101, the in-phase terminal 5 of the primary winding T of the transformer T101 is connected to the drain of the MOS transistor Q101, the source of the MOS transistor Q101 is grounded via the resistor R10, the primary winding T of the transformer T101 is disposed adjacent to the capacitor C101, the MOS transistor Q101 and the resistor R109 on the first surface of the PCB board, and all connections are connected by the shortest route. Specifically, the primary coil T of the transformer T101, the capacitor C101, the MOS transistor Q101, and the resistor R109 form a first loop 301 of an internal circuit, which may also be understood as a main working loop, wherein in order to reduce internal EMI conduction, the main working loop is designed in a small area, and specifically, the primary coil T of the transformer T101, the capacitor C101, the MOS transistor Q101, and the resistor R109 may be disposed adjacent to the first surface of the PCB board, and an internal trace thereof is a shortest trace, so as to ensure that the area of the main working loop is as small as possible.

In another embodiment, the in-phase terminal a of the secondary winding T3 of the transformer T101 is connected to the anode of the diode D201, and is connected to the inverting terminal B of the secondary winding T3 of the transformer T101 through the diode D201 and the capacitor C203 in sequence, the secondary winding T3 of the transformer T101 is disposed adjacent to the first surface of the PCB board of the diode D201 and the capacitor C203, and all connections are connected by the shortest route; specifically, the secondary winding T3 of the transformer T101, the diode D201 and the capacitor C203 form the second loop 302 of the internal circuit, which may be understood as an output loop of the switching power supply, wherein in order to reduce internal EMI conduction, the second loop 302 is designed to be small in area, and specifically, the secondary winding T3 of the transformer T101 may be disposed adjacent to the first surface of the PCB board of the diode D201 and the capacitor C203, and the internal trace thereof is the shortest trace, so as to ensure that the area of the second loop 302 is as small as possible.

In another embodiment, the in-phase terminal 4 of the power supply coil T1 of the transformer T101 is connected to the resistor R116 and is grounded via the resistor R116, the diode D106 and the capacitor C104 in sequence, the out-phase terminal 5 of the power supply coil T1 of the transformer T101 is grounded, the power supply coil T1 of the transformer T101 and the capacitor C104 are disposed adjacent to each other on the first surface of the PCB, the resistor R116 and the diode D106 are disposed adjacent to the second surface of the PCB and are disposed adjacent to each other in space with respect to the capacitor C104, and all connections are connected by the shortest route. Specifically, the power supply coil T1 of the transformer T101 and the capacitor C104, the resistor R116 and the diode D106 form a third loop 303, which can be understood as a power supply loop of the control circuit 80, wherein in order to reduce internal EMI conduction, the third loop 303 is designed to be small in area, specifically, the power supply coil T1 of the transformer T101 and the capacitor C104, the resistor R116 and the diode D106 can be disposed adjacent to each other in space, and the secondary coil T3 of the transformer T101 and the diode D201 and the capacitor C203 can be disposed adjacent to the first surface of the PCB in detail, and the internal trace is the shortest trace, so as to ensure that the area of the third loop 303 is as small as possible.

It can be understood that by forming a minimum loop for the current loop of the working coil of the transformer, the antenna effect of the working coil of the transformer can be reduced, the generation of interference frequency can be reduced, and the interference in the frequency band of 300MHz-450MHz can be further suppressed.

Further, the inverting terminal 4 of the power coil T1 of the transformer T101 and the ground pin of the capacitor C101 are grounded at a single point to the PCB. Specifically, the first loop 301 and the third loop 303 formed by the primary winding T of the transformer T101 and the power supply winding T1 of the transformer T101 are both grounded at a single point through the ground pin of the capacitor C101, that is, correspond to the internal ground point 304, which reduces internal EMI interference. Further suppressing the interference of the frequency band of 300MHz-450 MHz.

It is to be understood that the foregoing examples merely represent preferred embodiments of the present invention, and that the description thereof is more specific and detailed, but not intended to limit the scope of the invention; it should be noted that, for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention; therefore, all changes and modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (10)

1. A switching power supply, comprising: the protection circuit comprises a three-phase power supply input end, a protection circuit, a first filter circuit, a rectifying circuit, a transformation circuit, a second filter circuit, a direct-current voltage output end and a control circuit, wherein the three-phase power supply input end, the protection circuit, the first filter circuit, the rectifying circuit, the transformation circuit, the second filter circuit and the direct-current voltage output end are arranged on the same PCB;

the three-phase power input end is connected with the direct-current voltage output end through the protection circuit, the first filter circuit, the rectification circuit, the transformation circuit and the second filter circuit in sequence.

2. The switching power supply according to claim 1, wherein the first filter circuit comprises a common mode inductor LF101, a capacitor CX101, a resistor R103, and a resistor R104;

the first end of the common-mode inductor LF101 is connected with an L line of the three-phase power supply input end through the protection circuit, the third end of the common-mode inductor LF101 is connected with an N line of the three-phase power supply input end, the second end of the common-mode inductor LF101 is connected with the first input end of the rectification circuit, and the fourth end of the common-mode inductor LF101 is connected with the second input end of the rectification circuit;

one end of the capacitor CX101 is connected to the first end of the common-mode inductor LF101, and the other end of the capacitor CX101 is connected to the third end of the common-mode inductor LF 101;

the resistor R103 and the resistor R104 are connected in series and then connected in parallel to the capacitor CX 101.

3. The switching power supply according to claim 2, wherein said protection circuit comprises a fuse F101, a voltage dependent resistor MOV101 and a thermistor NTC 101;

fuse F101's one end is connected the L line of three-phase power input end, fuse F101's the other end is connected respectively thermistor NTC101 with piezo-resistor MOV101, and the warp thermistor NTC101 connects common mode inductance LF 101's first end and warp piezo-resistor MOV101 connects the N line of three-phase power input end.

4. The switching power supply according to claim 2, wherein the common-mode inductor LF101 is a UU9.8 filter common-mode inductor.

5. The switching power supply according to claim 1, wherein the second filter circuit comprises a common mode inductor LF201,

the first end of the common mode inductor LF201 is connected with the positive output end of the voltage transformation circuit, the second end of the common mode inductor LF201 is connected with the positive electrode of the direct current voltage output end, the third end of the common mode inductor LF201 is connected with the negative output end of the voltage transformation circuit, and the fourth end of the common mode inductor LF201 is connected with the negative electrode of the direct current voltage output end.

6. The switching power supply according to claim 5, wherein the second filter circuit further comprises a capacitor C207 and a capacitor C212;

one end of the capacitor C207 is connected to the first end of the common mode inductor LF201, the other end of the capacitor C207 is connected to the third end of the common mode inductor LF201, one end of the capacitor C212 is connected to the second end of the common mode inductor LF201, and the other end of the capacitor C212 is connected to the fourth end of the common mode inductor LF 201.

7. The switching power supply according to claim 5, wherein the common mode inductor LF201 is a vertical plug-in common mode inductor of T9 × 5 × 3.

8. The switching power supply according to claim 1, wherein the PCB board is a double-sided board including a first surface and a second surface.

9. The switching power supply according to claim 8, wherein the transformer circuit comprises a transformer T101, a capacitor C101, a diode D201 and a capacitor C203, and the control circuit comprises a MOS transistor Q101, a resistor R109, a resistor R116, a diode D106 and a capacitor C104; wherein:

the reverse end of the primary coil of the transformer T101 is grounded through the capacitor C101, the in-phase end of the primary coil of the transformer T101 is connected to the drain of the MOS transistor Q101, the source of the MOS transistor Q101 is grounded through the resistor R10, the primary coil of the transformer T101, the capacitor C101, the MOS transistor Q101 and the resistor R109 are arranged adjacent to the first surface of the PCB board, wherein all connections are connected by the shortest routing; and/or

The in-phase end of the secondary coil of the transformer T101 is connected to the anode of the diode D201, and is sequentially connected to the inverting end of the secondary coil of the transformer T101 through the diode D201 and the capacitor C203, the secondary coil of the transformer T101 is disposed adjacent to the first surface of the PCB board of the diode D201 and the capacitor C203, wherein all connections are connected by the shortest routing; and/or

The in-phase end of the power supply coil of the transformer T101 is connected with the resistor R116 and is sequentially grounded through the resistor R116, the diode D106 and the capacitor C104, the reverse-phase end of the power supply coil of the transformer T101 is grounded, the power supply coil of the transformer T101 and the capacitor C104 are arranged in the vicinity of the first surface of the PCB, the resistor R116 and the diode D106 are arranged in the vicinity of the second surface of the PCB and are arranged in the vicinity of the capacitor C104, and all connections are connected through shortest routing.

10. The switching power supply according to claim 9, wherein the inverting terminal of the power supply coil of the transformer T101 and the ground pin of the capacitor C101 are grounded at a single point with respect to the PCB.

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