Low-Voltage Sub-Nanosecond Pulsed Current Driver IC for High-Speed LIDAR Applications

This article introduces a new low voltage sub-nanosecond monolithic pulsed current driver for light detection and ranging (LIDAR) applications. A unique architecture based on a controlled current source and Vernier activation sequence, combined with a monolithic implementation, allows operation from low input voltage levels, high-resolution pico-seconds (ps) range pulse width, and rapid rise and fall times. An on-chip low voltage pulsed driver sub-nanosecond prototype has been implemented in a TS 0.18-μm 5-V-gated power management process. It incorporates an integrated wide range senseFET-based current sensor and a rail-to-rail comparator for current regulation. A separate line of investigation has been carried out to characterize the avalanche capabilities of the integrated lateral MOSFET power devices required for the driver IC. Several lateral diffused MOS (LDMOS) power devices have been custom designed and experimentally evaluated for life-cycle performance characterization. In addition, a delay-line (DL) based controller to govern the pulsed current driver IC is described and implemented on a field-programmable gate array (FPGA). To validate the concepts of the high-resolution LIDAR current driver, both discrete and IC experimental setups have been constructed and evaluated, validating the method for currents up to 20-A peak in discrete and 5 A in an integrated solution. Postlayout analysis and the experimental evaluation of the driver IC have been found to be in very good agreement. The experimental results demonstrate overall improvement on several operation properties, such as rise time, fall time, and pulse width resolution, of over one order of magnitude, compared to the state-of-the-art silicon-based LIDAR drivers. For 5-V input, and a representative output pulse of 5 A, the results that have been obtained are 900-ps rise time and fall time of 2.5 ns, all measured at the driver's light output. In addition, the pulse width resolution has been enhanced to hundreds of ps, which is significantly below the intrinsic delay of the power switches.