DC supply having low and high constant voltages for powering a polarity inverter controller

A power supply comprising:

• inverter means for converting an input voltage from a d.c. voltage source to an output voltage by chopping said input voltage at a predetermined frequency and supplying said output voltage to a load circuit;
• inverter control means for causing said inverter means to chop said input voltage in accordance with said output voltage so that said output voltage is maintained at a desired level under varying current of said load circuit;
• first, second, third and fourth resistors;
• a breakdown diode having a cathode connected through said first resistor to a negative terminal of said d.c. voltage source;
• and
• first, second and third transistors, each of said transistors having a base and first and second controlled electrodes,
• the base of said first transistor being connected to the anode of said breakdown diode, the first controlled electrode of said first transistor being connected to a positive terminal of said d.c. voltage source and further connected to the base of said first transistor through said second resistor, and the second controlled electrode of said first transistor being connected to the second controlled electrode of said third transistor,
• the base of said second transistor being connected to the anode of said breakdown diode, the first controlled electrode of said second transistor being connected through said third resistor to the base of said third transistor, and the second controlled electrode of said second transistor being connected to said negative terminal of said d.c. voltage source and further connected to a negative voltage supply terminal of said inverter control means, and
• the base and second controlled electrode of said third transistor being connected through said fourth resistor, and the first controlled electrode of said third transistor being connected to a positive voltage supply terminal of said inverter control means.