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

  • US 4,864,213 A
  • Filed: 12/12/1988
  • Issued: 09/05/1989
  • Est. Priority Date: 12/11/1987
  • Status: Expired due to Fees
First Claim
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1. 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;

    threshold means including a breakdown diode connected between first and second terminals of said d.c. voltage source;

    voltage sensing means including a transistor having a base connected to said breakdown diode for switching from a nonconducting state to a conducting state when said d.c. voltage exceeds a prescribed level determined by threshold voltages of said breakdown diode and said transistor; and

    current carrying means including a pair of transistors connected in series between said first terminal of said d.c. voltage source and a power supply terminal of said inverter control means, the transistors of said current carrying means being responsive to the switching of the transistor of said voltage sensing means to said conducting state for carrying current from said first terminal of said d.c. voltage source to said power supply terminal and developing at said power supply terminal a voltage which is substantially determined by threshold voltages of said breakdown diode and the transistor of said voltage sensing means and one of the transistors of said current carrying means.

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