Timing compensation for an excimer laser solid-state pulsed power module (SSPPM)

Abstract

For certain applications, it is critical to minimize variations in the (throughput) timing between trigger and the output pulse of a magnetic modulator. A circuit is described that maintains a relatively constant delay over a large operating voltage range (600-1150 V) and temperature range (25 /spl deg/C-65 /spl deg/C) range, The circuit operates by sampling the charging voltage and magnetic switch temperature just prior to the start switch trigger. Those parameters are then used to calculate the appropriate amount of delay to add into the low-level trigger chain to ensure that the delay stays constant over the voltage and temperature operating range. Although other approaches can be conceived and implemented, this particular design is relatively simple and inexpensive and meets the desired performance goals. Data presented show that the ideal correction function is nonlinear in nature and, as a result, simple linear approximations are limited in their ability to minimize the timing variations. Improvements to the original circuit use a multiple, piece-wise, linear approach in order to obtain better performance. The results are that an initial timing variation of almost 3 /spl mu/s has been reduced to a total variation of less than 100 ns.