Design Principle Analysis of Fiber Optic LED Driver Circuit

To reduce the proportion of data transmission time in the overall system processing time index, the data transmission rate should be not less than E1 (2.048 Mb / s) rate, and the communication link is required to be safe and reliable. Through the analysis of various data communication technologies, it is found that the optical link is the most satisfactory.

1, copper media data link analysis
Since high data transmission rate and long communication distance are required at the same time, it is difficult to meet the index requirements without coding and modulation in the copper medium link, but the high-speed modem is not only expensive, but also the time-consuming handshake process of both parties requires random real-time. The field where the data is transmitted will obviously not be applicable.

Most importantly, traditional copper dielectric links generate both electromagnetic interference signals and are susceptible to electromagnetic interference, and are less susceptible to EMC (electromagnetic compatibility) and EMI (electromagnetic interference) standards.

2. Analysis of fiber link
In people's traditional impression, it is uneconomical for fiber to be used for short-distance communication, but it has the advantages that copper media keys are incomparable:

2.1. The optical fiber link neither emits electromagnetic waves nor is it affected. There is no interference between the optical fibers, and the bit error rate is greatly reduced. Designers do not have to consider the environmental noise that may be coupled in;

2.2. Optical fiber provides electrical isolation between the two sides of the communication link, eliminating problems caused by different ground potentials between long-distance devices. At the same time, designers no longer have to worry about impedance matching;

2.3. The fiber optic transmitter can use a digital modulation drive circuit. The digital baseband signal can be directly driven by the fiber optic transmitter as long as it is simply line coded.

Now, the price of fiber optic devices has dropped sharply compared with the past. In the future, as the price of wire ropes rises and the price of fiber optic devices drops further, people will not consider the price factor first when choosing fiber. Therefore, we consider the rate and distance indicators, select the appropriate type of fiber, transceiver and its drive circuit to obtain a high-performance price-performance fiber communication key.

3. Choice of optical fiber communication devices
A basic fiber-optic communication system is very simple: an LED transmitter converts an electrical signal into an optical signal and couples it into a transmission fiber. The optical signal passes through the fiber to the optical receiver, which restores the received optical signal to its original state. Electrical signal output.