For Led Display 16-channel Constant Current Driver Chip Design

In recent years, with the advantages of high reliability, high brightness, wide viewing angle, low power consumption and long life, LED display gets rapid development and is widely used in the transmission of information indoor and outdoor. Meanwhile, as one of the core part of LED display, LED constant current driver IC also gets rapid development. Especially, multi channel output of constant current driver IC is used in more and more fields, because it can decrease the cost, power and convenient for PCB layout. Therefore, the research of multi-channel output constant current driver chips which is used in LED display has a very important practical value.According to main performance characteristics, this thesis analyzes the basic theory of the sub-module based on the analyzing and design of the system structure of16-channel output of constant current driver chip, finishes the design of actual circuits, and simulates the circuits by using EDA simulation tool. The simulation and verification of analog system and the design of layout is flnished,area of whole layout is2150X128Oμm2. The whole chip contains voltage reference module, OSC module, current regulator module, output module, power on reset module, thermal protection module and digital part.It used0.35μm BCD process, working temperature ranged from-40℃to85℃and supply voltage ranged from3.3V to5V. Except the current matching accuracy of the chips’and the channels’, the other analog simulation results are as follows. The output channels’current which can be regulated precisely by internal digital signal and outside resistor ranges from2mA to45mA. Its output voltage can reach20V. The typical power adjusting rate of the chip is0.14%/V, the typical load adjusting rate is0.0014%/V, the typical temperature coefficient is0.0018%/℃.When output channel is open, the rise time of the four groups channels’output current is5.5ns,7.2ns,9.8ns and12.7ns. When the output channels turn-off, the fall time of all channels’output current is less than2ns.Because the chip is on fabricating, this paper has no testing results.