Isolation transformer for use in isolated DC-to-DC switching power supply

• US 9,478,351 B2
• Filed: 05/24/2013
• Issued: 10/25/2016
• Est. Priority Date: 05/24/2013
• Status: Active Grant

• Current Assignee: Keithley Instruments, Inc.
• Original Assignee: Keithley Instruments, Inc.
• Inventors: Goeke, Wayne C., Gibbons, John C.
• Primary Examiner(s): Lian, Mangtin
• Application Number:
  US13/902,004
• Publication Number:
  US 20140347158A1
• Time in Patent Office: 1,250 Days
• Field of Search: 336/84.C, 336/221, 336/214, 336/215, 336/182, 174/36, 174/105.R, 174/108
• US Class Current: 1/1
• CPC Class Codes: H01F 2027/2833 using coaxial cable as wire
• CPC Class Codes: H01F 27/288 Shielding
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/363 made of electrically conductive material

Abstract

An isolated DC-to-DC switching power supply includes an isolation transformer having a magnetic core, a first winding around the magnetic core, a first winding-shield around the magnetic core, a second winding-shield within the first winding-shield, and a second winding within the second winding-shield. There is no direct coupling between the first winding and the second winding since the second winding is enclosed within the second winding-shield and the second winding-shield is enclosed within the first winding-shield.

Claims

1. An isolated DC-to-DC switching power supply, comprising:

an isolation power transformer including;

a magnetic core;

a first winding around the magnetic core;

a first electrostatic winding-shield around the magnetic core;

a second electrostatic winding-shield within the first electrostatic winding-shield; and

a second winding within the second electrostatic winding-shield,

such that the first winding electrostatically couples to the first electrostatic winding-shield and the second winding electrostatically couples to the second electrostatic winding-shield, such that there is no charge flow between the first electrostatic winding-shield and the second electrostatic winding-shield; and

wherein each of the first winding, the first electrostatic winding-shield, the second electrostatic winding-shield and the second winding are affixed to a printed circuit board.

2. The isolated DC-to-DC switching power supply of claim 1, wherein the isolation power transformer further includes a double-shielded cable comprising the first electrostatic winding-shield as an outer conductor of the double-shielded cable, the second electrostatic winding-shield as the inner conductor of the double-shielded cable, and the second winding as the center conductor of the double-shielded cable, and the first winding is a wire external to the double electrostatic winding-shielded cable.

3. The isolated DC-to-DC switching power supply of claim 1, in which the first electrostatic winding-shield is the first electrostatic winding-shield and a part of the first winding.

4. The isolated DC-to-DC switching power supply of claim 2, in which the first electrostatic winding-shield is the first electrostatic winding-shield and a part of the first winding.

5. The isolated DC-to-DC switching power supply of claim 1, in which the first electrostatic winding-shield is the first electrostatic winding-shield and all of the first winding.

6. The isolated DC-to-DC switching power supply of claim 2, in which the first electrostatic winding-shield is the first electrostatic winding-shield and all of the first winding.

7. The isolated DC-to-DC switching power supply of claim 1, in which the second electrostatic winding-shield is the second electrostatic winding-shield and part of the second winding.

8. The isolated DC-to-DC switching power supply of claim 2, in which the second electrostatic winding-shield is the second electrostatic winding-shield and part of the second winding.

9. The isolated DC-to-DC switching power supply of claim 1, in which the second electrostatic winding-shield is the second electrostatic winding-shield and all of the second winding.

10. The isolated DC-to-DC switching power supply of claim 2, in which the second electrostatic winding-shield is the second electrostatic winding-shield and all of the second winding.

11. The isolated DC-to-DC switching power supply of claim 1, wherein the isolation power transformer further includes a coaxial cable comprising a first electrostatic winding-shield as an outer conductor of the coaxial cable, and a center conductor is the second electrostatic winding-shield and the second winding, the first winding is a wire external to the coaxial cable.

12. The isolated DC-to-DC switching power supply of claim 1, wherein the isolation power transformer further includes a coaxial cable in which the outer conductor of the coaxial cable is the first winding and the first electrostatic winding-shield, and a center conductor is the second electrostatic winding-shield and the second winding.

13. The isolation power transformer of claim 2, wherein a plurality of double-shielded cables are wound in parallel through the magnetic core and connected together to create the first electrostatic winding-shield, the second electrostatic winding-shield, and the second winding.

14. The isolation power transformer of claim 11, wherein a plurality of coaxial cables are wound in parallel through the magnetic core and connected together to create the first electrostatic winding-shield, the second electrostatic winding-shield, and the second winding.