Kenneth D. Kieffer

A high-performance LED array driver ASIC with programmable thermal coefficients

The authors describe the design of an LED driver ASIC for use in a high-performance printing system using advanced CMOS technology. This ASIC provides digitally controllable constant-current sources capable of delivering up to 6 mA to each channel of an array of 96 LEDs with an effective 16-bit resolution. It features automatic in-situ temperatures compensation with field programmable temperature coefficients that can be digitally varied from 0.3% to 2% per degree Kelvin. These current sources possess excellent current regulation in response to wide LED loading conditions, and are insensitive to power supply fluctuations. Fabricated using an advanced 1.5 mu m CMOS n-well, double-metal, single-poly process, it measures approximately 7.6 mm by 3.8 mm.<<ETX>>