CN205647258U

CN205647258U - A circuit structure for reducing switching power supply EMI noise

Info

Publication number: CN205647258U
Application number: CN201620370447.2U
Authority: CN
Inventors: 傅贵; 陈伟栋; 李雪飞
Original assignee: Kai Hui Electronics Co Ltd Guangzhou
Current assignee: Kai Hui Electronics Co Ltd Guangzhou
Priority date: 2016-04-27
Filing date: 2016-04-27
Publication date: 2016-10-12
Anticipated expiration: 2026-04-27

Abstract

The utility model discloses a circuit structure for reducing switching power supply EMI noise, it includes power input end mould piece and rectifier module, still includes and connects the EMI filter module between power input end mould piece and rectifier module, EMI filter module is provided with a P common mode coil and a P+1 X electric capacity, if P is greater than 1, and P common mode coil series connection constitution common mode coil assembly in proper order then, L in power input end mould piece end, N end respectively through the common mode coil or the common mode coil assembly with rectifier module's stream input end is connected, the two output parallel connection X electric capacity of each common mode coil, remaining two pins of X electric capacity end respectively with L end in the power input end mould piece, N hold the connection. The utility model provides a circuit structure, its electromagnetic interference that can effectively reduce switching power supply makes the controllability of switching power supply product and uniformity higher.

Description

A kind of circuit structure for reducing switch power supply EMI noise

Technical field

This utility model relates to switch power technology field, is specifically related to a kind of circuit structure for reducing switch power supply EMI noise.

Background technology

Switching Power Supply is widely used in the various electronic equipments taken as the leading factor with electronic computer with small-sized, light weight and high efficiency feature, is that current electronics and information industry develops rapidly indispensable a kind of power mode.But owing to Switching Power Supply operating frequency is high, internal generation electric current quickly, change in voltage, Switching Power Supply can produce electromagnetic interference (EMI in the course of the work, Electromagnetic Interference), cause Switching Power Supply to produce stronger harmonic wave interference and spike disturbs, and the normal work of self circuit and other electronic equipments is affected by coupling paths such as conduction, radiation and crosstalks, the electronic functionalities that can cause surrounding time serious occurs abnormal, even can cause irremediable consequence.Therefore, it is necessary to provide a kind of circuit being effectively reduced switch power supply EMI noise.

Utility model content

For overcoming the problem of the deficiencies in the prior art and existence, this utility model provides a kind of circuit structure for reducing switch power supply EMI noise, and this circuit structure can effectively reduce the electromagnetic interference of Switching Power Supply, and the controllability making Switching Power Supply product is higher with concordance.

This utility model is achieved through the following technical solutions: a kind of circuit structure for reducing switch power supply EMI noise, including power input module and rectification module, described power input module includes L end, the N end being respectively used to be connected with L line, N line, also include the EMI filtration module being connected between power input module and rectification module, described EMI filtration module is provided with P co-mode coil and P+1 X electric capacity, described P is the positive integer more than or equal to 1, if P is more than 1, then P co-mode coil is sequentially connected in series composition co-mode coil group；

L end, N end in described power input module are connected with two inputs of described rectification module by co-mode coil or described co-mode coil group respectively, two outfans of each co-mode coil are connected in parallel an X electric capacity, and a remaining X electric capacity two pins end is connected with the L end in described power input module, N end respectively.

Further, described circuit structure also includes a Y capacitance module, and this Y capacitance module is provided with 2P Y capacitance, and two outfans of each co-mode coil are respectively by a Y capacitance ground connection；Described power input module also includes the PE end for ground connection, and in described Y capacitance module, one end of all of Y capacitance ground connection forms the earth terminal of Y capacitance module, and described PE end is connected with the earth terminal of described Y capacitance module.

Preferably, described PE end is connected with the earth terminal of described Y capacitance module by a ground wire loop；Described co-mode coil is high frequency common mode coil；The magnetic core of described high frequency common mode coil is preferably nickel zinc magnetic core.

The circuit structure that this utility model provides, it can effectively be imitated the electromagnetic interference of Switching Power Supply, greatly reduce the EMI noise of Switching Power Supply, so that apply the electronic equipment of this Switching Power Supply can stably run and not affect the normal work of periphery electronic equipment.

Accompanying drawing explanation

Fig. 1 is the structural representation of a kind of circuit structure for reducing switch power supply EMI noise in this utility model embodiment；

Wherein, drawing reference numeral is: 10-power input module, 20-rectification module, 30-EMI filtration module, 40-Y capacitance module, 50-ground wire loop.

Detailed description of the invention

For the ease of the understanding of those skilled in the art, below in conjunction with the drawings and specific embodiments, this utility model is described in further detail.

As shown in Figure 1, a kind of circuit structure for reducing switch power supply EMI noise, including power input module 10 and rectification module 20, described power input module 10 includes L end, the N end being respectively used to be connected with L line, N line, also include the EMI filtration module 30 being connected between power input module 10 and rectification module 20, described EMI filtration module 30 is provided with P co-mode coil and P+1 X electric capacity, described P is the positive integer more than or equal to 1, if P is more than 1, then P co-mode coil is sequentially connected in series composition co-mode coil group；L end, N end in described power input module 10 are connected with two inputs of described rectification module 20 by co-mode coil or described co-mode coil group respectively, two outfans of each co-mode coil are connected in parallel an X electric capacity, and a remaining X electric capacity two pins end is connected with the L end in described power input module 10, N end respectively.Wherein, described co-mode coil is preferably the magnetic core of high frequency common mode coil described in high frequency common mode coil and is preferably nickel zinc magnetic core.In the accompanying drawing 1 of the present embodiment, take P=3.

As the present embodiment preferred embodiment, described circuit structure also includes one for the Y capacitance module 40 as interference signal bypass channel, this Y capacitance module 40 is provided with 2P Y capacitance, and two outfans of each co-mode coil are respectively by a Y capacitance ground connection, as shown in Figure 1.

Further, described power input module 10 also includes the PE end for ground connection, in described Y capacitance module 40, one end of all of Y capacitance ground connection forms the earth terminal of Y capacitance module 40, and described PE end is preferably connected with the earth terminal of described Y capacitance module 40 by a ground wire loop 50.When Switching Power Supply internal structure is sufficiently complex, in the case of interference signal is king-sized, can be decayed interference signal by this ground wire loop 50, the big I of the actual inductance amount of ground wire loop 50 makees corresponding adjustment according to the size of interference signal.

The circuit structure that the present embodiment provides, it mainly realizes reducing the electromagnetic interference of Switching Power Supply by the combinative structure of the co-mode coil in EMI filtration module 30 Yu X electric capacity, and the circuit structure of co-mode coil and X electric capacity is as shown in Figure 1.In EMI filtration module 30, the quantity of co-mode coil is usually 2～5, and the most described P is preferably 2～5；Time actually used, according to Switching Power Supply watt level, interference signal magnitude does corresponding adjustment, can increase or reduce the quantity of P, the inductance value of co-mode coil also should be adjusted according to practical situation simultaneously, when determining the inductance value of co-mode coil, can first carry out conducting side to Switching Power Supply according to standard EMI method of testing, then the Frequency point of the limit value that is above standard is carried out EMI noise location, obtain optimal EMI test result finally by the inductance value combination changing each co-mode coil.After tested, take P=2 or P=3 in actual applications and obtain good EMI filter effect, i.e. so that Switching Power Supply is tested by EMI very well.

In prior art, the method for suppression electromagnetic interference conventional in Switching Power Supply adds shield winding for carrying out filtering, transformator between line at power input addition filter element, and switching tube adds buffer circuit or optimizes the design etc. of circuit board.Compared with prior art, the circuit structure provided in the present embodiment, its beneficial effect obtained has: (1) has only to add the combinational circuit structure of described EMI filtration module and Y capacitance module at Switching Power Supply input, can effectively solve the EMI problem of Switching Power Supply, its simple in construction, its filtering goes interference effect good and reliable, the electromagnetic interference of low switch power supply can be substantially reduced, so that apply the electronic equipment of this Switching Power Supply can stably run and not affect the normal work of periphery electronic equipment；(2) in use can less rely on the experience of Power Management Design personnel, only signal magnitude need to be disturbed to do adjust accordingly according to the Switching Power Supply watt level of switching capacity, the numerical value of P, the inductance value of co-mode coil as described in only need to adjust；(3) any negative impact will not be brought by the split powered-down body that is derived from, increase any inconvenience more will not to the manufacture of power supply product, thus the controllability of Switching Power Supply product can be made higher with concordance.

Above-described embodiment is preferably implementation of the present utility model, is not to restriction of the present utility model, and on the premise of without departing from inventive concept of the present utility model, any obvious replacement is all within protection domain of the present utility model.

Claims

1. the circuit structure being used for reducing switch power supply EMI noise, including power input module (10) and rectification module (20), described power input module includes L end, the N end being respectively used to be connected with L line, N line, it is characterized in that: also include the EMI filtration module (30) being connected between power input module and rectification module, described EMI filtration module is provided with P co-mode coil and P+1 X electric capacity, described P is the positive integer more than or equal to 1, if P is more than 1, then P co-mode coil is sequentially connected in series composition co-mode coil group；

Circuit structure the most according to claim 1, it is characterised in that: described circuit structure also includes a Y capacitance module (40), and this Y capacitance module is provided with 2P Y capacitance, and two outfans of each co-mode coil are respectively by a Y capacitance ground connection.

Circuit structure the most according to claim 2, it is characterized in that: described power input module also includes the PE end for ground connection, in described Y capacitance module, one end of all of Y capacitance ground connection forms the earth terminal of Y capacitance module, and described PE end is connected with the earth terminal of described Y capacitance module.

Circuit structure the most according to claim 3, it is characterised in that: described PE end is connected with the earth terminal of described Y capacitance module by a ground wire loop (50).

5. according to the circuit structure according to any one of Claims 1 to 4, it is characterised in that: described co-mode coil is high frequency common mode coil.

Circuit structure the most according to claim 5, it is characterised in that: the magnetic core of described high frequency common mode coil is nickel zinc magnetic core.