Active-Matrix Pixelated-LED Control System for Automotive Headlamps

This paper presents a driving circuitry system for high-resolution, pixelated-LED automotive headlamps. The system consists of an array of pixel drivers, and a row/column driver suitable for an active-matrix array configuration with the individual dimming control capabilities on each pixelated-LED An asynchronous serial communication protocol is introduced to minimize the number of data transmission interface signals between the row/column driver and pixel drivers. The proposed pixel driver is designed to drive each pixelated-LED with constant current and pulse width modulation (PWM). It contains a memory cell for dimming data, and a sample-and-hold driver stage to minimize the static power consumption of the pixel driver. The proposed system has been fabricated by using a 0.18-mu m CMOS process. The test chip includes a 2 x 16 pixel array with an embedded row/column driver. The functional operation has been verified with an 8 x 16 LED array system prototype.