CN207652305U

CN207652305U - A kind of Switching Power Supply EMC filter circuit of low cost

Info

Publication number: CN207652305U
Application number: CN201721820382.8U
Authority: CN
Inventors: 徐志亮; 石金明; 王小明; 陈新革; 邹志坚; 任小林
Original assignee: ZHONGSHAN CHANGHONG ELECTRIC CO Ltd
Current assignee: ZHONGSHAN CHANGHONG ELECTRIC CO Ltd
Priority date: 2017-12-21
Filing date: 2017-12-21
Publication date: 2018-07-24
Anticipated expiration: 2027-12-21

Abstract

The utility model discloses a kind of Switching Power Supply EMC filter circuits of low cost, the π type filter modules formed including sequentially connected rectification module, by inductance L1 and electrolytic capacitor, Switching Power Supply, π types filter module outside rectification module access can filter out the EMC interference of Switching Power Supply generation and reduce the pulsation of direct current, applied in low power Switching Power Supply, the design can effectively filter out the EMC interference of Switching Power Supply generation and reduce the pulsation of direct current, cost is relatively low, volume is also relatively small, and circuit setting is simple.

Description

A kind of Switching Power Supply EMC filter circuit of low cost

Technical field

The utility model is related to filter out the circuit field of EMC interference, the Switching Power Supply EMC filtering of especially a kind of control panel Circuit.

Background technology

It is applied at present for the filter circuit of Switching Power Supply EMC interference in control circuit board, as shown in Figure 1, general meeting The EMC interference generated by the π type filtering module for filtering off Switching Power Supplies that capacitance C1 ' common mode inductances L1 ', capacitance C2 ' are formed, then It is exported after reducing the pulsation of direct current by rectification module and filter capacitor C30 filter actions, however it is lower in power It in control circuit board, such as applies in the control circuit board of air-conditioning, uses 5W or below Switching Power Supplies, common mode inductance L1 ' Cost it is higher, volume is larger, and advantage is had no in cost, and in control circuit board, after rectification circuit, generally can all set It is exported after being equipped with the pulsation of filter capacitor C30 filter actions reduction direct current, is based on this structure, the applicant changes circuit Into.

Utility model content

In order to solve the above technical problems, the purpose of this utility model is to provide a kind of lower-cost Switching Power Supply EMC filters Wave circuit.

The technical solution adopted in the utility model is：

A kind of Switching Power Supply EMC filter circuit of low cost, including sequentially connected rectification module, π type filter modules, it is whole Switching Power Supply, π types filter module outside flow module access can filter out the EMC interference of Switching Power Supply generation and reduce direct current The pulsation of electricity, rectification module include cathode output end and cathode output end, and π type filter modules include electrolytic capacitor C31, electrolysis electricity Hold C32 and inductance L1, one end of inductance L1 is electrical with the cathode output end of the anode of electrolytic capacitor C31, rectification module respectively The other end of connection, inductance L1 is electrically connected with the anode of electrolytic capacitor C32 respectively；The cathode of electrolytic capacitor C31 respectively with it is whole The cathode output end of flow module, the cathode of electrolytic capacitor C32 are electrically connected.

The rectification module includes the poles L input terminal and the poles N input terminal, the poles the L input terminal of rectification module and the L of Switching Power Supply Pole is electrically connected, and the poles the N input terminal of rectification module and the poles N of Switching Power Supply are electrically connected, and further include for absorbing surge current Varistor ZNR1, the poles the L input terminal of one end of varistor ZNR1 and rectification module is electrically connected, varistor ZNR1's The poles the N input terminal of the other end and rectification module is electrically connected.

Further include insurance resistance FUSE1, insurance resistance FUSE1 is extremely defeated with the poles L of Switching Power Supply, the L of rectification module respectively Enter end to be electrically connected.

The beneficial effects of the utility model：

The utility model Switching Power Supply EMC filter circuit, the design inductance L1 uses lower-cost colour loop inductance, with two A electrolytic capacitor constitutes π type filter modules, and after rectification module, π types filter module is both used to filter out Switching Power Supply generation EMC interference be also used for reduce direct current pulsation, be applied to low power Switching Power Supply in, the design can effectively filter out open The pulsation of EMC interference and reduction direct current that powered-down source generates, cost is relatively low, and volume is also relatively small, and circuit setting is simple.

Description of the drawings

Specific embodiment of the present utility model is described further below in conjunction with the accompanying drawings.

Fig. 1 is the circuit diagram of traditional switch power supply EMC filter circuit.

Fig. 2 is the circuit diagram of the utility model Switching Power Supply EMC filter circuit.

Specific implementation mode

As shown in Fig. 2, the utility model Switching Power Supply EMC filter circuit, including the filter of sequentially connected rectification module 1, π types Wave module 2, rectification module 1 accesses external Switching Power Supply, π types filter module 2 can filter out the EMC interference that Switching Power Supply generates And the pulsation of direct current is reduced, rectification module 1 includes cathode output end and cathode output end, and π types filter module 2 includes electrolysis Capacitance C31, electrolytic capacitor C32 and inductance L1, one end of inductance L1 respectively with the anode of electrolytic capacitor C31, rectification module 1 Cathode output end is electrically connected, and the other end of inductance L1 is electrically connected with the anode of electrolytic capacitor C32 respectively；Electrolytic capacitor C31 Cathode respectively with the cathode of the cathode output end of rectification module 1, electrolytic capacitor C32 be electrically connected.

Wherein, the design, which can follow conventional lines, is arranged in control circuit board for the capacitance of direct current ripple filtering, electricity Sense L1 can be used lower-cost colour loop inductance, such as the operating power of the small-power switching power-supply of the design is 5W, 5W or with Under the Switching Power Supply filter capacitor of power be generally made of the electrolytic capacitor of a 4.7U/450V or 6.8U/450V, filter herein Wave capacitance is made of the electrolytic capacitor C32 of the electrolytic capacitor C31 and 3.3U/450V of 3.3U/450V, and is inserted into one in centre The colour loop inductance L1 of 102uH/100MA, to form π type filter modules, cutoff frequency can be obtained according to formula By two 3.3UF electrolytic capacitors Form 6.6UF) because the test bandwidth of conduction is 150KHZ → 30MHZ, it is possible thereby to the inductance value by changing colour loop inductance To adjust cutoff frequency.

The design uses lower-cost colour loop inductance, π types filter module 2 is constituted with two electrolytic capacitors, by whole After flow module 1, the EMC interference that π types filter module 2 is both used to filter out Switching Power Supply generation is also used for reducing the pulsation of direct current, Applied in low power Switching Power Supply, the design can effectively filter out the EMC interference of Switching Power Supply generation and reduce direct current The pulsation of electricity, cost is relatively low, and volume is also relatively small, and circuit setting is simple, stable and reliable for performance in use, is suitble to high-volume raw Production.

Rectification module 1 includes the poles L input terminal and the poles N input terminal, the poles the L input terminal of rectification module 1 and the poles L of Switching Power Supply It is electrically connected, the poles the N input terminal of rectification module 1 and the poles N of Switching Power Supply are electrically connected, and further include for absorbing surge current One end of varistor ZNR1, varistor ZNR1 and the poles the L input terminal of rectification module are electrically connected, and varistor ZNR1's is another One end and the poles the N input terminal of rectification module 1 are electrically connected.

Further include insurance resistance FUSE1, insurance resistance FUSE1 is extremely defeated with the poles L of Switching Power Supply, the L of rectification module 1 respectively Enter end to be electrically connected.

Varistor ZNR1, insurance resistance FUSE1 herein, which respectively plays filter circuit, to be absorbed surge current, prevented The effect of carrying row and protecting against shock, the operation of effective protection circuit.

The foregoing is merely the preferred embodiments of the utility model, the utility model is not limited to above-mentioned embodiment party Formula, if with essentially identical means realize the technical solution of the utility model aim belong to the scope of protection of the utility model it It is interior.

Claims

1. a kind of Switching Power Supply EMC filter circuit of low cost, it is characterised in that：It is filtered including sequentially connected rectification module, π types Wave module, the external Switching Power Supply of rectification module access, π types filter module can filter out the EMC interference of Switching Power Supply generation with And the pulsation of direct current is reduced, rectification module includes cathode output end and cathode output end, and π type filter modules include electrolytic capacitor C31, electrolytic capacitor C32 and inductance L1, one end of inductance L1 respectively with the anode of electrolytic capacitor C31, the anode of rectification module Output end is electrically connected, and the other end of inductance L1 is electrically connected with the anode of electrolytic capacitor C32 respectively；Electrolytic capacitor C31's is negative Pole is electrically connected with the cathode of the cathode output end of rectification module, electrolytic capacitor C32 respectively.

2. a kind of Switching Power Supply EMC filter circuit of low cost according to claim 1, it is characterised in that：The rectification Module includes the poles L input terminal and the poles N input terminal, and the poles the L input terminal of rectification module and the poles L of Switching Power Supply are electrically connected, rectification The poles the N input terminal of module and the poles N of Switching Power Supply are electrically connected, and further include the varistor ZNR1 for absorbing surge current, One end of varistor ZNR1 and the poles the L input terminal of rectification module are electrically connected, the other end and the rectification mould of varistor ZNR1 The poles the N input terminal of block is electrically connected.

3. a kind of Switching Power Supply EMC filter circuit of low cost according to claim 2, it is characterised in that：Further include protecting The poles the L input terminal of dangerous resistance FUSE1, insurance resistance FUSE1 respectively with the poles L of Switching Power Supply, rectification module is electrically connected.