A SiC Based Two-Stage Pulsed Power Converter System for Laser Diode Driving and Other Pulsed Current Applications

Abstract

High-power laser diodes (LDs) are used in various military, medical, and industrial applications. In this article, the unique driving requirements of a high power pulsed LD array have been presented, and the required converter architecture has been discussed. A two-stage capacitive energy storage based pulsed power converter system consisting of a phase shifted full bridge (PSFB) based capacitor charging power supply (CCPS) and a buck based pulse current source with inductor energy recovery has been adopted. SiC FETs have been employed to increase the pulsed power capability of the switching regulator based pulse current source as an alternative to the conventionally used linear current driver. A reconfigured pulse forming circuit has been proposed for the pulse current source, which mitigates the effect of the output parasitic inductance on the LD without the need for an additional freewheeling diode across the load. The impact of inductor energy recovery on the semiconductor device's transient thermal stress in the pulse current source has been investigated. The tradeoff between the energy storage capacitance and the filter inductor in the pulse current source has been studied. A pulsed LD driver capable of driving 280 V LD arrays has been designed, and a hardware prototype has been built. The complete system has been experimentally demonstrated by generating 50 A current pulses at 250 V output voltage, validating the proposed converter configuration for high pulsed power LD driving applications.