CN203039650U

CN203039650U - Communication bus filtering device

Info

Publication number: CN203039650U
Application number: CN 201220622972
Authority: CN
Inventors: 张勃
Original assignee: Xi'an Kairong Electronic Technologies Co Ltd
Current assignee: Xi'an Kairong Electronic Technologies Co Ltd
Priority date: 2012-11-22
Filing date: 2012-11-22
Publication date: 2013-07-03
Anticipated expiration: 2022-11-22

Abstract

The utility model relates to a filter and particularly relates to a communication bus filtering device. The communication bus filtering device comprises a first common-mode inductor and a second common-mode inductor, wherein the first common-mode inductor is formed by an inductor LA, an inductor LB, an inductor LC and magnetic cores, and the second common-mode inductor is formed by an inductor LA', an inductor LB', an inductor LC' and magnetic cores; the inductor LA and the inductor LA' are in series connection with a circuit A of the communication bus filtering device; the inductor LB and the inductor LB' are in series connection with a circuit B of the communication bus filtering device; the inductor LC and the inductor LC' are in series connection with a circuit C of the communication bus filtering device; and a ground capacitor CyA, a ground capacitor CyB and a ground capacitor CyC are respectively arranged between a series connection point of the inductors (LA and LA') and a shield ground, between a series connection point of the inductors (LB and LB') and a shield ground, and between a series connection point of the inductors (LC and LC') and a shield ground. A signal line filter for an interface RS232 is provided, and the interference resistance of the interface RS232 is improved.

Description

A kind of communication bus filter

Technical field

The utility model relates to a kind of filter, more particularly, relates to a kind of communication bus filter.

Background technology

Along with the high speed development of microelectric technique, computer technology, control technology, by the universal standard serial line interface RS232 that the EIA of EIA formulates, become the standard interface of data terminal equipment (DTE) and data communications equipment (DCE).Be in the fields such as the RS232 interface of the core point to point communication system that extensively is incorporated in industries such as electric power, telecommunications, bank, industry control, supervisory control system, stored-program control exchange billing terminal, satellite receiver with the integrated circuit.For being extensive use of of RS232 interface, corresponding Anti-interference Design technology (being electromagnetic compatibility EMC) has become more and more important.Disturb and can directly cause the hardware damage of system by interface cable sometimes, though can not damage the hardware of system sometimes, often make the system program operation of microprocessor out of control, cause controlling malfunctioning, thereby cause equipment and production accident.Therefore, how improving antijamming capability and the reliability of RS232 interface in system is important content very important in application, also is one of key of Computer Control Technology application and popularization.RS232 has two kinds of interfaces, 9 pins and 25 pins, and the simplest three lines that are connected to that the RS-232 bus is commonly used connect.

Summary of the invention

The purpose of this utility model is to provide a kind of signal line filter for the RE232 interface, improves a kind of communication bus filter of RS232 interface antijamming capability.

To achieve these goals, the technical solution of the utility model is: the multiplex telephony line filter, it is characterized in that: it comprises the first common mode common mode inductance that common mode inductance LA, LB and LC and magnetic core constitute, second common mode inductance that common mode inductance LA ', LB ' and LC ' and magnetic core constitute, common mode inductance LA and common mode inductance LA ' are connected in series on the communication bus filter A line loop, and common mode inductance LB and common mode inductance LB ' are connected in series on the communication bus filter B line loop; Common mode inductance LC, common mode inductance LC ' are connected in series on the communication bus filter C line loop, be connected in series a little and shield between the ground at common mode inductance LA and LA ', be connected in series a little and shield between the ground at common mode inductance LB and LB ', being connected in series a little and shielding at common mode inductance LC and common mode inductance LC ' has common mode capacitance CyA, CyB, CyC over the ground respectively between the ground.

Described magnetic core is selected nickel-zinc ferrite for use.

The described CyA of common mode capacitance over the ground, CyB, CyC are the little three terminal capacitor of earth impedance or feedthrough capacitor or patch capacitor.

Described first common mode inductance, second common mode inductance are packed in the shield shell.

The utility model has the advantages that the filter circuit that adopts common mode inductance that suitable Ferrite Material turns to and the little common mode capacitance of earth impedance to form carries out filtering to the RS232 interface, can effectively suppress the interference on the interface cable, improve the antijamming capability of product, avoid causing equipment and production accident.

Description of drawings

Below in conjunction with drawings and Examples the utility model is further specified:

Fig. 1 is circuit theory diagrams in the specific embodiment;

Fig. 2 is the filter cut-away view.

Among the figure: 1, common mode inductance LA; 2, common mode capacitance CyA; 3, common mode inductance LA '; 4, common mode inductance LB; 5, common mode capacitance CyB; 6, common mode inductance LB '; 7, common mode inductance LC; 8, common mode capacitance CyC; 9, common mode inductance LC '.

Embodiment

As shown in Figure 1, the communication bus filter, it comprises first common mode inductance that common mode inductance LA1, common mode inductance LB4 and common mode inductance LC7 and magnetic core constitute; Second common mode inductance that common mode inductance LA ' 3, common mode inductance LB ' 6 and common mode inductance LC ' 9 and magnetic core constitute; Common mode inductance LA1 and common mode inductance LA ' 3 are connected in series on the communication bus filter A line loop, and common mode inductance LB4 and common mode inductance LB ' 6 are connected in series on the communication bus filter B line loop; Common mode inductance LC7, common mode inductance LC ' 9 are connected in series on the communication bus filter C line loop, be connected in series a little and shield between the ground at common mode inductance LA1 and common mode inductance LA ' 3, be connected in series a little and shield between the ground at common mode inductance LB4 and common mode inductance LB ' 6, being connected in series a little and shielding at common mode inductance LC7 and common mode inductance LC ' 9 has common mode capacitance CyA2, common mode capacitance CyB5, common mode capacitance CyC8 over the ground respectively between the ground.

Magnetic core is selected nickel-zinc ferrite for use, and nickel-zinc ferrite can not cause energy loss to signal on the one hand, can effectively suppress electromagnetic interference on the other hand.

Common mode capacitance CyA2, CyB5, CyC8 are the little three terminal capacitor of earth impedance or feedthrough capacitor or patch capacitor over the ground, and direct-to-ground capacitance can effectively suppress the High-frequency Interference on the cable.

First common mode inductance, second common mode inductance are packed in the shield shell.

Communication bus adopts the RS232 bus, and as shown in Figure 2, filter seals in device interior RS232 interface one end, and shell contacts with cabinet inwall conduction.The total line filter of RS232 can effectively suppress the interference on the interface cable, improves the antijamming capability of product, avoids causing equipment loss and accident.

Above content be in conjunction with concrete preferred implementation to further describing that the utility model is done, can not assert that concrete enforcement of the present utility model is confined to these explanations.

Claims

1. communication bus filter, it is characterized in that: it comprises the first common mode common mode inductance that common mode inductance LA, LB and LC and magnetic core constitute, second common mode inductance that common mode inductance LA ', LB ' and LC ' and magnetic core constitute, common mode inductance LA and common mode inductance LA ' are connected in series on the communication bus filter A line loop, and common mode inductance LB and common mode inductance LB ' are connected in series on the communication bus filter B line loop; Common mode inductance LC, common mode inductance LC ' are connected in series on the communication bus filter C line loop, be connected in series a little and shield between the ground at common mode inductance LA and LA ', be connected in series a little and shield between the ground at common mode inductance LB and LB ', being connected in series a little and shielding at common mode inductance LC and common mode inductance LC ' has common mode capacitance CyA, CyB, CyC over the ground respectively between the ground.

2. a kind of communication bus filter according to claim 1, it is characterized in that: described magnetic core is selected nickel-zinc ferrite for use.

3. a kind of communication bus filter according to claim 1, it is characterized in that: the described CyA of common mode capacitance over the ground, CyB, CyC are the little three terminal capacitor of earth impedance or feedthrough capacitor or patch capacitor.

4. a kind of communication bus filter according to claim 1, it is characterized in that: described first common mode inductance, second common mode inductance are packed in the shield shell.