CIRCUIT FOR REDUCING STRAY CAPACITY EFFECTS IN TRANSFORMER WINDINGS

• US 3,562,623 A
• Filed: 07/16/1968
• Issued: 02/09/1971
• Est. Priority Date: 07/16/1968
• Status: Expired due to Term

• Current Assignee: Robert P. Farnsworth
• Original Assignee: Robert P. Farnsworth
• Inventors: Farnsworth, Robert P.
• Application Number:
  US04/745,245
• Time in Patent Office: 938 Days
• US Class Current: 363/20
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: H02M 3/3378 in a push-pull configuration of the parallel type H02M3/3374 takes precedence
• CPC Class Codes: H02M 7/10 arranged for operation in series, e.g. for multiplication of voltage

Abstract

A transformer charging system that provides a highly efficient operation and that substantially eliminates switching transients. The high voltage or secondary winding of the transformer as well as the primary winding in some arrangements, is divided into segments which are isolated from each other by unidirectional current conductive devices such as diodes. For charging a load coupled to the secondary winding, current pulses are repetitively applied to the primary winding from the power source with the flyback voltage resulting from the pulse terminations causing current to flow through the diodes. The diodes allow the stray capacitance associated with each segment to initially charge but prevent them from discharging between the repetitive operations, which would cause additional flow of primary current and dissipation losses.

Claims

1. A system for charging a load comprising:

a source of energy pulses having a predetermined polarity;

transformer means having first and second winding structures, each with first and second ends and with said first and second ends of said first winding structure coupled to said source of energy pulses;

a plurality of first unidirectional current conductive means with a different one coupled between each of a plurality of selected portions of said second winding structure and each with a first polarity along a current path through said second winding between said first and second ends; and

and second and third unidirectional currenT conductive means respectively coupling said first and second ends of said second winding structure to said load, each with said first polarity relative to said current path through said second winding.

2. An energy transfer device comprising:

first and second inductively coupled windings each having first and second ends, said second winding being divided into segments;

a source of current pulses coupled to the first and second ends of said first winding; and

a plurality of diode means each having an anode and a cathode and with a different one of said diode means coupled between each of the segments and to the first and second ends of said second winding, all of said diode means being coupled with a similar anode to cathode polarity along said second winding.

3. The combination of claim 2 in which said first winding is also divided into segments and a plurality of diode means, each having an anode and a cathode, are coupled between each of the segments and to said first and second ends of said first winding, all of said diode means being coupled with a similar anode to cathode polarity along said second winding.

4. A system for transferring energy to a load having first and second terminals comprising:

a transformer having first and second windings each having first and second ends, said second winding being formed of segments;

a power source coupled to the first end of said first winding;

switching means coupled to the second end of said first winding; and

a plurality of diodes each having an anode and a cathode and with a diode coupled between adjacent segments and a diode coupled between each of the first and second terminals of the load and the respective first and second ends of said second winding, said diodes having similar anode to cathode polarity through said second winding between said first and second terminals of said load.

5. A pulse forming system for providing high voltage pulses to an output terminal comprising:

a transformer having first and second windings, each with first and second ends, said second winding being formed of a plurality of segments;

a first voltage source coupled to the first end of said first winding;

a second voltage source;

switching means coupled between the second end of said first winding and said second voltage source;

control means coupled to said switching means for periodically passing a pulse of current through said second winding during a first period and inhibiting said pulse of current during a second period;

a pulse forming network having first, second and third terminals;

a plurality of diodes, each having an anode and a cathode and with a diode coupled between each point of adjacent segments and a diode respectively coupled between each of the first and second ends of said second winding and said first and second terminals of said pulse forming network, said diodes having a similar anode to cathode polarity so that said diodes are reverse biased during said first period and current flows through said second winding and said pulse forming network during said second period; and

a controllable switch coupled between the third terminal of said pulse forming network on said output terminal for controllably passing a high voltage pulse to said output terminal.

6. The combination of claim 5 in which said first winding is formed of a plurality of segments and including a plurality of diodes, each having an anode and cathode and with a diode coupled between adjacent segments and a diode coupled between said first voltage source and the first end of said first winding, said diodes in said first winding having a similar anode to cathode polarity so that said diodes in said first winding conduct during said first period and are reverse biased during said second period.

7. A DC to DC converter comprising:

an output terminal;

a source of two phase driving diving pulses;

a transformer having a first and second windings;

each having first and second ends and a center point and each being divided into segments on both sides of said center point;

first switching means coupled between said source of driving pulses and the first end of said first winding, second switching means coupled between said source of driving pulses and the second end of said first winding;

a source of potential coupled to the center points of each of said first and second windings;

a plurality of first diodes, each having an anode and a cathode with a first diode coupled between the ends of adjacent segments of said first winding, between said first and second switching means and the respective first and second ends of said first winding and between the segments at the center point and said source of reference potential, said first diodes having opposite anode to cathode potentials on opposite sides of said center point; and

a plurality of second diodes each having an anode and a cathode with a second diode coupled between the ends of adjacent segments of said second winding, between the first and second ends of said second winding and the output terminal and between the segments at the center point and said source of reference potential, said second diodes having opposite anode to cathode potentials on opposite sides of said center point.