Simplified power supply for long pulse CO2 laser using zero cross switching technique

We propose a simple power supply for a longitudinally pulsed CO2 laser with long pulse duration by the switching control of AC line (60 Hz) on HV leak age transformer primary, which can generate long pulse of about 3 ms compar ed to a typical pulsed power supply. In this power supply, a low voltage op en loop control for high voltage discharge circuit is employed to avoid the HV sampling or switching, and AC line voltage switched directly by a SCR i s applied to the leakage transformer primary. Thus, there is no need of a r ectified bridge and an energy-storage capacitor in the discharge circuit, a nd the leakage transformer allows one to omit a current-limiting resistor. In order to control the laser output power, the pulse repetition rate is ad justed up to 60 Hz. A ZCS circuit and a PIC one-chip microprocessor are use d io control the gate signal of SCR precisely. (C) 2001 Published by Elsevi er Science Ltd.