TW201444280A - Filtering circuit and electrical connector - Google Patents

Abstract

A filtering circuit includes a first side, a second side, and a plurality of transmitting passageways disposed therebetween. Each transmitting passageway includes a transformer and a common mode choke. The transformer includes a first winding and a second winding each including two connecting taps and a center tap. The transformer connects with the first side. The common mode choke includes a third winding, a fourth winding, and a fifth winding. The third winding and the fifth winding connect the transformer to the second side. The fourth winding is disposed between the third winding and the fifth winding. The fourth winding does not connect with the center tap and connects to ground.

Description

Filter circuit and electrical connector

The invention relates to a filter circuit for an electrical connector, and more particularly to a ground connection of a common mode suppressor in a filter circuit.

For the prior art, please refer to the publication of Chinese Patent Application No. CN102769438A, published on Nov. 7, 2012, which discloses a filter circuit related to the present invention. The filter circuit has a first side and a second side and a plurality of transmission channels connected between the two sides, each of the transmission channels including a transformer and a common mode suppressor. The transformer includes a first coil and a second coil coupled to each other, each coil having two connecting ends and a center tap, and the two connecting ends of the first coil are connected to the first side. The common mode suppressor has a third coil, a fourth coil and a fifth coil, the two ends of the second coil are connected to one end of the third coil and the fifth coil, and the other ends of the third coil and the fifth coil are connected to the second side. The fourth coil of the common mode suppressor is connected to the center tap of the transformer, and the other end is connected in series with a capacitor and grounded.

The above filter circuit is connected to the center tap of the transformer by the fourth coil of the common mode suppressor. When the high frequency signal is input, the high frequency noise will be chaotic between the common mode suppressor and the transformer, thereby causing the filtering effect. bad.

The problem to be solved by the present invention is to provide a filter circuit having a good filtering effect.

In order to solve the above technical problem, the technical means of the present invention is: a filter circuit having a first side and a second side and a plurality of transmission channels connected between the two sides, each of the transmission channels including a transformer and a common mode rejection The transformer includes a first coil and a second coil coupled to each other, each coil has two connecting ends and a center tap, two connecting ends of the first coil are connected to the first side, and the common mode suppressor has a third coil, a fourth coil and a fifth coil, wherein the two ends of the second coil are connected to one ends of the third coil and the fifth coil, the other ends of the third coil and the fifth coil are connected to the second side, and the fourth coil is grounded, and Not connected to the center tap of the transformer.

After adopting the structure of the invention, the fourth coil of the common mode suppressor is directly connected to the center tap of the transformer and directly grounded, and the high frequency noise can be directly turned on to the ground, which reduces common mode interference and has good filtering effect. In addition, the electrical connectors using the above filter circuit are also protected together.

1, 1’. . . transformer

10, 10’. . . Cable side

100, 100’. . . Filter circuit

11, 11’. . . Primary coil

111, 111’. . . Connection end

112, 112’. . . Center tap

12, 12’. . . Secondary coil

121, 121’. . . Connection end

122, 122’. . . Center tap

2, 2’. . . Common mode suppressor

20, 20’. . . Physical side

201, 201’. . . Power terminal

202, 202’. . . Ground terminal

21, 21’. . . Third coil

211, 211', 231, 231'. . . First joint

212, 212', 232, 232'. . . Second joint

22, 22’. . . Fourth coil

221, 221’. . . First joint

222, 222’. . . Second joint

23, 23’. . . Fifth coil

3, 3’. . . Filter component

30, 30’. . . Transmission channel

4, 4', 5, 5'. . . Ground

6, 6’. . . capacitance

The first figure is a filter circuit diagram of the first embodiment of the present invention.

The second figure is a filter circuit diagram of a second embodiment of the present invention.

The third figure is a schematic diagram of a channel shown in the first figure.

The fourth figure is a comparison of the first embodiment of the present invention with the prior art electromagnetic interference test.

As shown in the first figure, it is a first embodiment of the present invention. A filter circuit 100 for a network connector having a cable side 10, a physical side 20, and four transmission channels 30 (third diagram) between the cable side 10 and the physical side 20. Each transmission channel 30 has a transformer 1 and a common mode suppressor 2 electrically connected to each other. The transformer 1 is close to the cable side 10 and the common mode suppressor 2 is close to the physical side 20. The transformer 1 includes a primary coil 11 and a secondary coil 12 coupled to each other, and the primary coil 11 and the secondary coil 12 each have two terminals and a center tap. The two connection ends 121 of the secondary coil 12 are connected to the cable side 10, and the center tap 122 of the secondary coil 12 is connected in series with the filter element 3 and then grounded 4. The filter element 3 may be formed by a resistor and a capacitor connected in series, or may be only a capacitor, or may be an air discharge device. The air discharge device can be a helium gas tube or formed from two conductive sheets on the circuit board. The filter element 3 shown in the figure is an air discharge device. The common mode suppressor 2 is a three-wire common mode suppressor including a third coil 21, a fourth coil 22, and a fifth coil 23. The third coil 21, the fourth coil 22, and the fifth coil 23 each have opposite first and second joints. The first joint 211 of the third coil 21 and the first joint 231 of the fifth coil 23 are connected to the connection end 111 of the primary coil 11 of the transformer 1. The second joint 212 of the third coil 21 and the second joint 232 of the fifth coil 23 are connected to the physical side 20. The first joint 221 and the second joint 222 of the fourth coil 22 are directly grounded 5 or connected in series with a capacitor (not shown) and grounded 5, and are not connected to the center tap 112 of the primary coil 11 of the transformer 1. The physical side 20 has a power terminal 201 and a ground terminal 202, and a center tap 112 of the primary coil 11 of the transformer 1 is connected to the power terminal 201. The ground terminal 202 is connected in series with a capacitor 6 in parallel with the power supply terminal 202, and then connected to the center tap 112 of the primary coil 11 of the transformer 1. The voltage of the power terminal 201 is generally about 3V.

As shown in the second figure, it is a second embodiment of the present invention. A filter circuit 100' for a network connector having a cable side 10', a physical side 20', and four transmission channels between the cable side 10' and the physical side 20'. Each of the transmission channels has a transformer 1' and a common mode suppressor 2' electrically connected to each other. The transformer 1' is close to the physical side 20' and the common mode suppressor 2' is close to the cable side 10'. The transformer 1' includes a primary coil 11' and a secondary coil 12' coupled to each other, and the primary coil 11' and the secondary coil 12' each have two terminals and a center tap. The two connection ends 111' of the primary coil 11' are connected to the physical side 20', and the center tap 122' of the secondary coil 12' is connected in series with the filter element 3' to the ground 4'. The filter element 3' may be formed by a resistor and a capacitor connected in series, or may be only a capacitor, or may be an air discharge device. The air discharge device can be a helium gas tube or formed from two conductive sheets on the circuit board. The filter element 3' shown in the figure is an air discharge device. The common mode suppressor 2' is a three-wire common mode suppressor including a third coil 21', a fourth coil 22', and a fifth coil 23'. The third coil 21', the fourth coil 22' and the fifth coil 23' each have a first joint and a second joint, the second joint 212' of the third coil 21' and the second joint 232' of the fifth coil 23' Connected to the connection end 121' of the transformer 1' secondary coil 12', the first joint 211' of the third coil 21' and the first joint 231' of the fifth coil 23' are connected to the cable side 10'. The first joint 221' and the second joint 222' of the fourth coil 22' are directly grounded 5' without being connected to the center taps 112', 122' of the transformer 1'. The physical side 20' has a power terminal 201' and a ground terminal 202', and the center tap 112' of the primary coil 11' of the transformer 1' is connected to the power terminal 201'. The ground terminal 202' is connected in series with a capacitor 6' in parallel with the power supply terminal 202' and then connected to the center tap 112' of the primary coil 11' of the transformer 1'. The voltage of the power supply terminal 201' is generally about 3V.

As shown in the third figure, it is a schematic diagram of a channel 30 shown in the second figure. The high frequency noise can be directly connected to the ground 5 through the fourth coil 22 of the common mode suppressor 2, thereby avoiding the introduction of high frequency noise into the transformer 1, and the noise of the power terminal 201 cannot be passed through the center of the transformer 1. The conduction of the tap to the common mode suppressor 1 causes the noise to go back and forth.

As shown in the fourth figure, a comparison diagram of the electromagnetic interference test of the center tap of the transformer connected to the fourth coil of the common mode suppressor and the fourth coil of the common mode suppressor is directly grounded. The A line is the common mode interference test diagram when the fourth coil is connected to the center tap of the transformer, and the B line is the common mode interference test line when the fourth coil is grounded. The horizontal axis is the test frequency (in MHZ) and the vertical axis is the common mode interference (in dB). The filter circuit works at about 100 MHz, and the noise frequency is generally around 250, 500, 750 MHz. It can be seen that the filter circuit has better common mode rejection when the fourth coil of the common mode suppressor is directly grounded.

An electrical connector that applies a filter circuit 100 or a filter circuit 100'. The electrical connector includes: a mating terminal for connecting with the cable side mating connector, a mounting terminal for connecting to the physical side mother board, and a circuit board module for electrically connecting the mating terminal to the mounting terminal, the circuit board A plurality of transformers and a common mode suppressor are disposed on the module. Such an electrical connector can be obtained by modifying the filter circuit diagram on the prior art Chinese Patent Application Publication No. CN102446616A. The electrical connector further includes an insulative housing and a mask housing surrounding the insulative housing and the circuit board module, the common mode suppressor being a three-wire common mode suppressor, and the fourth coil being connected to the mask housing by a conductive path on the circuit board After grounding.

1. . . transformer

10. . . Cable side

100. . . Filter circuit

11. . . Primary coil

111. . . Connection end

112, 122. . . Center tap

12. . . Secondary coil

121. . . Connection end

2. . . Common mode suppressor

20. . . Physical side

201. . . Power terminal

202. . . Ground terminal

twenty one. . . Third coil

211, 231. . . First joint

212, 232. . . Second joint

twenty two. . . Fourth coil

221. . . First joint

222. . . Second joint

twenty three. . . Fifth coil

3. . . Filter component

4, 5. . . Ground

6. . . capacitance

Claims (10)

A filter circuit having a first side, a second side, and a plurality of transmission channels connected between the two sides, each of the transmission channels including a transformer and a common mode suppressor, the transformer including a first coil and a second coupled to each other a coil, each coil has two connecting ends and a center tap, two connecting ends of the first coil are connected to the first side, the common mode suppressor has a third coil, a fourth coil and a fifth coil, and the second coil is connected The end is connected to one end of the third coil and the fifth coil, and the other end of the third coil and the fifth coil is connected to the second side, wherein the fourth coil is grounded and is not connected to the center tap of the transformer. The filter circuit of claim 1, wherein the fourth coil has an opposite first joint and a second joint, and the first joint and the second joint are directly grounded. The filter circuit of claim 1, wherein the first side is a cable side, the second side is a physical side, the common mode suppressor is close to a physical side, and the transformer is close to a cable side. The center tap of the second coil is connected to the physical side, and the center tap of the first coil is connected in series with a filter component and grounded. The filter circuit of claim 1, wherein the first side is a physical side, the second side is a cable side, the transformer is close to a physical side, and the common mode suppressor is close to a cable side. The center tap of the first coil is connected to the physical side, and the center tap of the second coil is connected in series with a filter component and grounded. The filter circuit of claim 3, wherein the filter element is a capacitor or an air discharge device. The filter circuit of claim 3, wherein the physical side has a power terminal, and a center tap of the second coil is connected to the power terminal. The filter circuit of claim 4, wherein the physical side has a power terminal, and a center tap of the first coil is connected to the power terminal. The filter circuit of claim 6 or 7, wherein the power terminal is connected in parallel with a capacitor and connected to a center tap of the first coil or the second coil. An electrical connector, comprising: the filter circuit according to any one of claims 1 to 4, wherein the electrical connector comprises: a docking terminal for connecting with a cable side docking connector, for The mounting terminal of the physical side mother board is connected, and the circuit board module electrically connecting the docking terminal to the mounting terminal, and the transformer and the common mode suppressor are mounted on the circuit board module. The electrical connector of claim 9, wherein the electrical connector further comprises: an insulative housing and a mask housing surrounding the insulative housing and the circuit board module, the common mode suppressor being a three-wire common mode a suppressor, the fourth coil being grounded by being connected to the mask housing by a conductive path on the circuit board.