Laser power supply

Claim 1

A power supply for a gas discharge laser having first and second anodes and a cathode being comprised of a DC high voltage converter to be operated in a pulse width modulated mode and having first and second input terminals and an output terminal, said first input terminal receiving unregulated power and providing in response thereto an output of DC high voltage for application to said first anode of said gas discharge laser, first and second preselected resistors connected in a series arrangement from said output terminal to ground to form a voltage divider network, a first amplifier having an input and output and receiving at said input a control signal, an emitter follower having a base, emitter, and collector, said base being connected to said output of said first amplifier, said collector connected to said cathode of said gas discharge laser, a third preselected resistor connected between said emitter and ground, said first amplifier and emitter follower forcing current through said preselected third resistor so as to be equal to the laser current control voltage divided by the value of said third resistor, a fixed reference voltage source, a second amplifier providing a control voltage equal to the fixed reference voltage applied thereto minus said laser current control voltage, and a third amplifier receiving said control voltage and also a preselected voltage from said voltage divider network, said third amplifier providing an error voltage to said second input of said DC high voltage converter varying the duty cycle of the pulse width modulated voltage converter such that the high voltage is regulated to a value equal to the fixed reference voltage minus the laser current control voltage multiplied by the sum of said preselected first and second resistors divided by said preselected second resistor.