PCB Reverse Engineering

Introduction to PCB Reverse Signal Isolation Technology

 1. PCB Reverse isolates the serial data stream
In the PCB Reverse isolation digital signal has a large range of options. If the data stream is bit-serial, then the selection scheme ranges from simple optical coupling
To the isolated transceiver IC. Key design considerations include:
(1) the required data rate;
(2) the system isolation side of the power requirements;
(3) whether the data channel must be bidirectional.
Optocouplers based on LED PCBs are the first to isolate design issues. There are now available LED-based ICs with data rates of 10Mb / s and above. An important design consideration is that the LEC light output decreases over time. An excess current must be provided for the LED in the early stage so that sufficient output light intensity can be provided over time. The need to provide an excess current is a serious problem since the supply of electrical power at the isolated end may be limited. Because the drive current required by the LED can be greater than the current available from a simple logic output stage, a special driver circuit is often required.
2. PCB Reverse isolation parallel data bus system
Parallel digital data bus isolation There are six main design parameters, the serial isolation on the basis of the increase will be three more main
To the design parameters:
(1) the bit width of the bus;
(2) the allowable degree of deviation;
(3) clock speed requirements.
This can be accomplished with a row of optocouplers, but the support circuitry can be quite complex. A mismatch in propagation time between the optocouplers will result in data skew, resulting in data errors at the receiver. To minimize this problem, an isolated digital coupler is used to support double buffered data buffering at the input and output.
3. PCB Reverse analog signal isolation
In many systems, the analog signal must be isolated. The analog signal takes into account the circuit parameters that are completely different from the digital signal.
Analog signals are usually considered first:
(1) isolation accuracy;
(2) linearity;
(3) frequency response;
(4) noise considerations;
(5) isolated power supply.
On the power supply, to high demand, especially for the input stage, requiring the power input stage, the ground is not subject to interference from other parts of the circuit, that is, isolated power supply. It should also be noted that the basic accuracy or linearity of the isolation amplifiers can not be improved by the corresponding application circuit, but these circuits can reduce noise and reduce the input stage power requirements.
 4. PCB Reverse isolation with the multi-functional IC
A multifunctional data acquisition IC with isolation provides the designer with the opportunity to perform multiple tasks while spanning the isolation screen. A complete data acquisition device can include multiple analog switches, sample and hold circuits, programmable gain instrumentation amplifiers, A / D converters and one or more digital I / O channels. All of these functions are controlled through a serial data port.
There are many devices available for designers to use, and use the system in the ground potential of the design of a very different. Each device is designed for unique system requirements. The high level of performance integration of new devices allows for more complex operations that can not be done before across the isolation barrier.


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