A SiC based Two-Stage Pulsed Power Converter System for Laser Diode Driving Applications

This paper discusses the unique driving requirements of a laser diode array and evaluates potential converter configurations to meet those requirements. 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. Buck based pulse current source with inductor energy recovery enabled by SiC FETs allows significant reduction in energy loss and required energy storage capacitance when compared to conventionally used linear current regulator. A reconfigured pulse forming circuit has been proposed for the pulse current source which mitigates the effect of the output parasitic inductance on the laser diode without the need for an additional freewheeling diode across the load. A pulsed laser diode driver capable of driving 280 V laser diode arrays at 56 kW peak pulse power has been designed and a full-scale hardware prototype has been built. The complete system has been experimentally validated by generating 50 A current pulses at 250 V output voltage (12.5 kW) which proves the feasibility of the proposed converter configuration for high pulse power laser diode driving applications.