Common-mode signal suppression circuit and switch

Abstract

The invention discloses a common-mode signal suppression circuit belonging to the electronic field. The common mode signal suppression circuit is used for suppressing the common-mode signal when a first chip and a second chip carry out the signal interaction, wherein the first chip is used as the transmitting end. The common-mode signal suppression circuit comprises an isolating transformer. Two ends of the primary coil of the isolating transformer are connected with the anode and the cathode of the differential pair of the first chip; the driving current of the primary coil is supplied when the differential pair of the first chip outputs the set signal; two ends of the secondary coil of the isolating transformer are connected with the anode and the cathode of the differential pair of thesecond chip; and the ratio of the primary coil to the secondary coil is 1:1. Therefore, the common-mode signal generated from the sudden change of the voltage due to the leakage inductance of the isolating transformer can be eliminated, the hidden danger resulted from the electromagnetic interference can be reduced, and the quality of carrying out the signal interaction by the transmitting end and the receiving end can be improved. The invention also discloses a signal interaction circuit and a switch.

Description

Technical field [0001] The invention relates to the field of electronics, in particular to a common mode signal suppression circuit. Background technique [0002] In a general Ethernet switch, the signal is generally transmitted to the physical layer chip through the RJ45 connector and the isolation transformer. The RJ45 connector is a connector that connects the MDI interface (an interface defined by IEEE802.3) and the network cable. Refer to figure 1 As shown, the circuit between the RJ45 connector and the physical layer chip is implemented on a Print Circuit Board (PCB) board, and this circuit is the aforementioned MDI interface. Through RJ45 connectors and network cables, the interconnection between the physical layer chips in different switches can be realized. [0003] Refer to figure 2 As shown, the physical layer chip 1 and the physical layer chip 2 are interconnected in the above manner (the RJ45 connector and the network cable between the two isolation transformers are ...

AI Technical Summary

Problems solved by technology

The common mode signal will not only cause serious electromagnetic interference (EMI), but also seriously affect the signal quality of the transmitted signal and the received signal

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