CN107947546A

CN107947546A - A kind of inexpensive Switching Power Supply EMC filter circuit

Info

Publication number: CN107947546A
Application number: CN201711391883.3A
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: 2018-04-20

Abstract

The invention discloses a kind of inexpensive Switching Power Supply EMC filter circuit, 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 sets simple.

Description

A kind of inexpensive Switching Power Supply EMC filter circuit

Technical field

The present invention relates to the Switching Power Supply EMC filtered electricals of the circuit field for filtering out EMC interference, particularly a kind of control panel Road.

Background technology

Apply at present for the filter circuit of Switching Power Supply EMC interference in control board, as shown in Figure 1, general meeting The EMC that the π type filtering module for filtering off Switching Power Supply being made of capacitance C1 ' common mode inductances L1 ', capacitance C2 ' produces is disturbed, then Exported after the pulsation of direct current is reduced by rectification module and filter capacitor C30 filter actions, however it is relatively low in power In control board, such as apply in the control board of air-conditioning, use 5W or following Switching Power Supply, common mode inductance L1 ' Cost it is higher, volume is larger, and advantage is had no in cost, and in control board, after rectification circuit, generally can all set It is equipped with after filter capacitor C30 filter actions reduce the pulsation of direct current and exports, based on this structure, the applicant changes circuit Into.

The content of the invention

In order to solve the above technical problems, the object of the present invention is to provide a kind of lower-cost Switching Power Supply EMC filtered electricals Road.

The technical solution adopted by the present invention is：

A kind of inexpensive Switching Power Supply EMC filter circuit, 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 types filter module includes electrolytic capacitor C31, electrolysis electricity Hold C32 and inductance L1, the cathode with electrolytic capacitor C31, the cathode output end of rectification module are electrical respectively for one end of inductance L1 Connection, the other end cathode electric connection with electrolytic capacitor C32 respectively of inductance L1；The anode of electrolytic capacitor C31 respectively with it is whole The cathode output end of flow module, the anode of electrolytic capacitor C32 are electrically connected.

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

Insurance resistance FUSE1 is further included, the L poles with Switching Power Supply, the L of rectification module are extremely defeated respectively by insurance resistance FUSE1 Enter end to be electrically connected.

Beneficial effects of the present invention：

Switching Power Supply EMC filter circuit of the present invention, the design inductance L1 use lower-cost colour loop inductance, with two electricity Solve capacitance and form π type filter modules, after rectification module, π types filter module is both used for the EMC for filtering out Switching Power Supply generation Interference is also used for reducing the pulsation of direct current, and applied in low power Switching Power Supply, the design can effectively filter out switch electricity The EMC interference and the pulsation of reduction direct current that source produces, cost is relatively low, and volume is also relatively small, and circuit sets simple.

Brief description of the drawings

The embodiment of the present invention 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 Switching Power Supply EMC filter circuit of the present invention.

Embodiment

As shown in Fig. 2, Switching Power Supply EMC filter circuit of the present invention, including sequentially connected rectification module 1, π types filtering mould Block 2, rectification module 1 access outside Switching Power Supply, π types filter module 2 can filter out Switching Power Supply generation EMC interference 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 electrolytic capacitor C31, electrolytic capacitor C32 and inductance L1, one end of inductance the L1 cathode with electrolytic capacitor C31, the cathode of rectification module 1 respectively Output terminal is electrically connected, the other end cathode electric connection with electrolytic capacitor C32 respectively of inductance L1；Electrolytic capacitor C31's is negative The cathode output end with rectification module 1, the anode of electrolytic capacitor C32 are electrically connected respectively for pole.

Wherein, the design, which can follow conventional lines, is arranged in control board for the capacitance to direct current ripple filtering, electricity Sense L1 can use 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 Ripple capacitance is made of the electrolytic capacitor C32 of the electrolytic capacitor C31 and 3.3U/450V of 3.3U/450V, and in centre insertion one The colour loop inductance L1 of 102uH/100MA, so as to form π type filter modules, cutoff frequency can be obtained according to formula (C is by two 3.3UF electrolytic capacitor groups Into 6.6UF) because conduction test bandwidth be 150KHZ → 30MHZ, it is possible thereby to by change the inductance value of colour loop inductance come Adjust cutoff frequency.

The design uses lower-cost colour loop inductance, π types filter module 2 is formed with two electrolytic capacitors, by whole After flow module 1, the EMC that π types filter module 2 is both used to filter out Switching Power Supply generation disturbs the pulsation for being also used for reducing 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 is set simply, stable and reliable for performance in use, is adapted to high-volume raw Production.

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

Insurance resistance FUSE1 is further included, the L poles with Switching Power Supply, the L of rectification module 1 are extremely defeated respectively by insurance resistance FUSE1 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, effectively protects circuit operation.

The foregoing is merely the present invention preferred embodiments, the present invention is not limited to the above embodiment, if with Essentially identical means realize that the technical solution of the object of the invention is belonged within protection scope of the present invention.

Claims

A kind of 1. inexpensive Switching Power Supply EMC filter circuit, it is characterised in that：Filtered including sequentially connected rectification module, π types Ripple module, the exterior 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 types filter module includes electrolytic capacitor C31, electrolytic capacitor C32 and inductance L1, the cathode of one end of inductance the L1 cathode with electrolytic capacitor C31, rectification module respectively Output terminal is electrically connected, the other end cathode electric connection with electrolytic capacitor C32 respectively of inductance L1；Electrolytic capacitor C31's is negative The cathode output end with rectification module, the anode of electrolytic capacitor C32 are electrically connected respectively for pole.
A kind of 2. inexpensive Switching Power Supply EMC filter circuit according to claim 1, it is characterised in that：The rectification Module includes L poles input terminal and N poles input terminal, and the L poles input terminal of rectification module and the L poles of Switching Power Supply are electrically connected, rectification The N poles input terminal of module and the N poles of Switching Power Supply are electrically connected, and further include the varistor ZNR1 for absorbing surge current, One end of varistor ZNR1 and the L poles input terminal of rectification module are electrically connected, the other end and the rectification mould of varistor ZNR1 The N poles input terminal of block is electrically connected.
A kind of 3. inexpensive Switching Power Supply EMC filter circuit according to claim 2, it is characterised in that：Further include guarantor The L poles with Switching Power Supply, the L poles input terminal of rectification module are electrically connected respectively by dangerous resistance FUSE1, insurance resistance FUSE1.