A Driving Circuit Design For LED Display System

LED lighting which is a new type of semiconductor solid-state light source, isbecoming more and more popular. In addition of its unique features, such asprotection of environment, energy saving, long life, durable, small size, fast response,convenient regulation, the advantages of rich colors, it quickly becomes the hottestnew technology of energy-saving and environmental protection.In this paper, we analyzed multiple cascade, single cascade, ComparedManchester code with RZ(return to zero) code realization scheme when took singlecascade, studied low logic source consumption, high reliability, and low powerconsumption in details. I finally choose the RZ code scheme, asynchronous circuitway to realize the LED driver chip. In this system, data is transfered in serial, eachchip cut the data it needs to display, transferring the left data to the next chip afterrecoding, I use a long time low level to indicate the reset signal, so we can get rid ofthe address frame and reset frame, and reduce the complexity; in the meantime,avoiding the decay of waveforms coming along with the commonly used bypass wayfor transferring in a long distance, increased reliability. When decoding the inputsignal, I use only two D flip-flops and several logic gates to construct the statemachine, so I can save a large number of logic resource, and increase the input signaldeviation tolerance. The chip is designed as a asynchronous circuit, the timing ofinternal data’s sampling, decoding, counting, and display is well processed by severallogic circuits, and compared with synchronous circuit, it has a smaller size andsmaller power consumption.The chip take0.5um CMOS process, the result of compile shows that the logicresource consumption of this scheme is only8.94%of the Manchester code scheme,and the size of layout is only30.1%of the Manchester code scheme which used the0.35um CMOS process, chip test result shows that it’s power consumption is only 14.3%of the chip which realized by the Manchester code scheme, the system’s powerconsumption and chip size reached the design requirements.