| In the LED lighting system, if we want to achieve large-scale lighting systems, we must cascade more LED chip to achieve large-screen display, but this,would consequent driver chip cascade problem. In light of this problem, the cascade of signal transmission between the LED driver chip has better stability, better battery life and lower power consumption has been is a hot research topic in the field of LED large screen dot matrix display.The topic for the single-line LED driver chip based on the the Manchester code transmission signal,which generated signal attenuation in the multi-level chip cascade.base on in-depth study the reason of the system signal attenuation law and simulation analysis of the original design, and according to the analysis of the results as well as the data protocol of the chip,increased a self-detect self-compensating signal function module for this drive chip. In this design, according to the law that the high level of per-chip signal attenuation is1.33ns and high level decays to220ns would occurs to the recognition error, add a judgment attenuation margin settings for the signal compensation mechanism.Compare the half-cycle time of the signal waveform with the high level time in the reset frame, if their difference is in line with the judgment attenuation margin,then open compensation module, this avoid the compensation module need to compensate for the signal from time to time, and reduce the circuit power consumption. Meanwhile, according to the protocol requirements, via logic to compensate attenuation only for the next reset frame and the data frame but not the sync frame.Finally, increase the circuit internal logic to strengthen the compensation capacity of the circuit, achieve to compensate the signal one step in place. While this increase the circuit logic resources, but to solve the problem of each level of the original design chip can only compensate a1.59ns. This design achieve to the desired functional requirements. |
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