Power source circuit

• US 4,954,758 A
• Filed: 10/25/1988
• Issued: 09/04/1990
• Est. Priority Date: 10/30/1981
• Status: Expired due to Fees

• Current Assignee: LPI Acquisition Co.
• Original Assignee: XCEL Corp.
• Inventors: Rusk, George R.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US07/221,936
• Time in Patent Office: 679 Days
• Field of Search: 315/411, 363/21, 358/190
• US Class Current: 315/411
• CPC Class Codes: H02M 3/3155 with automatic control of the output voltage or current

Abstract

The high voltage power supply for the CRT display of a computer system is modified by the addition of tightly coupled, unitarily wound secondary windings feeding current to rectifier diodes oriented to conduct during the horizontal scan. These secondary windings and diodes provide a stable, regulated source of D.C. power for the remaining modules of the computer system.

Claims

1. A power source circuit comprising:

a horizontal sweep flyback transformer having a magnetic core with an oversized cross section, having wound next to said core a plurality of unitarily-wound power supply windings, having an insulative layer over said power supply windings, having wound over said insulative layer a primary winding, and also having a high-voltage secondary windings and a commutating secondary winding;

a source of alternating current;

rectification means connecting to said source of alternating current for rectifying said alternating current to provide an unregulated direct current potential source;

voltage regulator means for drawing current intermittently from said unregulated direct current potential source and for providing a non-isolated, regulated direct current potential source, said voltage regulator means including a series circuit formed from the flyback transformer'"'"'s commutating secondary winding and a triggerable controlled conduction device having a trigger input;

a horizontal sweep circuit comprising two circuit elements connected in series across said non-isolated, regulated direct current potential source, the first circuit element comprising the flyback transformer'"'"'s primary winding, and the second circuit element comprising the parallel combination of an electronic switch operated at the horizontal sweep frequency rate, a damper diode, and a horizontal deflection coil circuit;

high-voltage rectification means connected in series with the flyback transformer'"'"'s high-voltage secondary winding and oriented to conduct during horizontal retrace intervals, rather than during horizontal scanning intervals, for rectifying the retrace interval voltage peaks;

a plurality of series circuits formed from diode rectifiers connected in series with filter capacitors, each of said series circuits connecting across one or more of said plurality of power supply windings, said series circuit diode rectifiers being oriented to conduct during horizontal scanning intervals, rather than during horizontal retrace intervals, each of said filtering capacitors forming an isolated, regulated direct current potential source;

at least one high wattage load whose wattage needs fluctuate substantially over time connecting to at least one of said isolated, regulated direct current potential sources; and

scan regulator and pulse generation means for regulating said isolated and regulated direct current potential sources by adjusting the timing, relative to the horizontal retrace interval, of trigger pulses provided to said controlled conduction device, said scan regulator and pulse generation means having a feedback input connecting to at least one of said isolated, regulated direct current potential sources and having a pulse output connecting to said trigger input of said controlled conduction device;

whereby a power supply is achieved in which fluctuations in load currents drawn from the isolated, regulated direct current potential sources do not adversely affect the operation of the high voltage and horizontal deflection circuitry.

2. A power supply circuit in accordance with claim 1 wherein the scan regulator and pulse generation means includes a second feedback input connecting to said unregulated direct current potential source.