Strobe power supply

Apparatus for controllably and intermittently energizing a gaseous discharge tube of a warning light from a direct current source to cause the generation of groups of light pulses, the pulses within each group being closely spaced in time and the groups of pulses being separated in time by an interval which greatly exceeds the interval between pulses of each group, the gaseous discharge tube having an anode and a cathode and the warning light including a trigger voltage transformer associated with the discharge tube, said apparatus comprising:

• a power transformer, said transformer having at least a primary winding, a secondary winding and a feedback winding;
• blocking oscillator means, said oscillator means including a first controllable semiconductor device connected in series with said transformer primary winding and the direct current source, said semiconductor device having an emitter, a collector and a base, said oscillator means further including said transformer feedback winding, said first semiconductor device being periodically switched between conductive and non-conductive states at a first frequency to cause current flow through said transformer primary winding when said first semiconductor device is in the conductive state whereby said oscillator means will cause an alternating voltage to be induced in said transformer secondary winding;
• means responsive to gating signals for selectively disabling said oscillator means, said disabling means establishing a conductive path between the base and emitter of said first semiconductor device when in the disabling mode;
• first capacitor means connected to said transformer secondary winding for storing energy induced therein through operation of said oscillator means, said first capacitor means having first and second polarity terminals;
• means for connecting the first polarity terminal of said first capacitor means to the anode of the gaseous discharge tube;
• means for generating timing pulses at a second frequency, and second frequency being lower than said first frequency and said timing pulses having a predetermined duration;
• means responsive to said timing pulses for generating a plurality of control pulses in response to each timing pulse;
• means responsive to said control pulses for generating gaseous discharge tube trigger pulses, said trigger pulse generating means including nominally non-conductive solid state switch means responsive to said control pulse, said trigger pulse generating means further comprising second capacitor means connected in series with the trigger voltage transformer primary winding, switching of said switch means to the conductive state establishing a discharge path for said second capacitor means whereby a trigger voltage pulse of sufficient magnitude to cause conduction of the gaseous discharge tube will be induced in the trigger voltage transformer secondary winding, said first capacitor means discharging through the gaseous discharge tube when the tube is rendered conductive by a trigger voltage pulse;
• means establishing a charging path for said second capacitor means, said charging path establishing means coupling said second capacitor means to said first polarity terminal of said first capacitor means;
• means for limiting level to which said second capacitor means will be charged;
• voltage sensitive means connected to said first capacitor means, said voltage sensitive means generating a first command signal when the voltage across said first capacitor means reaches a predetermined level;
• and
• means responsive to command signals generated by said voltage sensitive means for applying a gating signal to said disabling means to cause the disabling of said oscillator means.