Analysis And Design Of A DC-DC Dual-Channel Digital Isolator

In the high pressure,high speed,high precision and long distance communications,the isolation devices often be used to ensure the accuracy of the transmission signal and personnel safety.The isolator that introduced in this paper is a dual-channel digital isolator based on iCoupler technology.Combining high speed CMOS and monolithic transformer technology,these isolation components provide outstanding performance characteristics superior to alternatives such as photocoupler device.This isolation use the internal circuit to realize the encoding and decoding function,so the high repeatability make the isolation able to integrate multiple transmission channel on the same chip,and support two-way transimission of signals with the high channel matching degree.The calibrate and refresh signal function also can be realized by the internal circuit of isolation,and the wave-shaping circuit on the output can help to improve the accuracy of the transmitted signal.In addition,this kind of isolation have the low power operation,high temperature operation,high data rate,precise timing characteristics and high common-mode transient immunity,it can be used on a lot of applications,such as size-critical multichannel isolation,SPI interface/data converter isolation,RS-232/RS-422/RS-485 transceiver isolation and digital field bus isolation.The DC-DC dual-channel digital isolator includes three parts:two circuit diagrams and a monolithic transformer part.The paper just introduce the design of the two circuit diagrams,and the monolithic transformer part is not given.First,the general framework design of the circuit is given.Then,the structures and functions of every small part are introduced.You also can find the logic simulation of these small circuit diagrams.The circuit is fabricated with CSMC 0.5 μm double-poly double-metal CMOS technology.For the general circuit diagram,paper by using Cadence Spectre software realize the circuit simulation of the logic,the supply current,the propagation delay,the logic volages and so on.Finally,the layout is given by the Cadence Virtuoso integration tools.