Energy transfer element with capacitor compensated cancellation and balance shield windings

Patent metadata

Field	Value
Publication number	US-9722499-B2
Application number	US-201514962903-A
Country	US
Kind code	B2
Filing date	Dec 8, 2015
Priority date	Dec 8, 2015
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

Energy transfer element circuitry for use in a power converter includes a cancellation shield winding wound around an energy transfer element core. A first trimming capacitor is coupled to a first end of the cancellation shield winding to adjust a shield response of the cancellation shield winding. A second end of the cancellation shield winding is unconnected. A primary winding is wound around the energy transfer element core. A balance shield winding is wound around the energy transfer element core. A second trimming capacitor is coupled to a second end of the balance shield winding to adjust a shield response of the cancellation shield winding. A first end of the balance shield winding is unconnected. A secondary winding is wound around the energy transfer element core.

First claim

What is claimed is:

1. Energy transfer element circuitry for use in a power converter, comprising:
a cancellation shield winding wound around an energy transfer element core;
a first trimming capacitor coupled to a first end of the cancellation shield winding to adjust a shield response of the cancellation shield winding, wherein a second end of the cancellation shield winding is unconnected, wherein a first end of the first trimming capacitor is coupled to a first input supply rail of a power converter, and wherein a second end of the first trimming capacitor is coupled to the first end of the cancellation shield winding;
a primary winding wound around the energy transfer element core;
a balance shield winding wound around the energy transfer element core;
a second trimming capacitor coupled to a second end of the balance shield winding to adjust a shield response of the balance shield winding, wherein a first end of the balance shield winding is unconnected, wherein a second end of the second trimming capacitor is coupled to a second input supply rail of the power converter, and wherein a first end of the second trimming capacitor is coupled to the second end of the balance shield winding; and
a secondary winding wound around the energy transfer element core.

2. The energy transfer element circuitry of claim 1 , wherein a first end of the primary winding is coupled to a first input supply rail of a power converter, wherein a second end of the primary winding is coupled to a switch of the power converter.

3. The energy transfer element circuitry of claim 1 , wherein a first end of the secondary winding is coupled to an output rectifier of a power converter, wherein a second end of the secondary winding is coupled to an output return of the power converter.

4. The energy transfer element circuitry of claim 1 , wherein the primary winding is wound around the energy transfer element core over the cancellation shield winding.

5. The energy transfer element circuitry of claim 4 , wherein the balance shield winding is wound around the energy transfer element core over the primary winding.

6. The energy transfer element circuitry of claim 5 , wherein the balance shield winding comprises copper foil wound over the primary winding.

7. The energy transfer element circuitry of claim 5 , wherein the balance shield winding comprises magnet wire wound over the primary winding.

8. The energy transfer element circuitry of claim 5 , wherein the secondary winding is wound around the energy transfer element core over the balance shield winding.

9. The energy transfer element circuitry of claim 8 , wherein each layer of the cancellation shield winding, the primary winding, the balance shield winding, and the secondary winding are separated from each other with tape layers.

10. The energy transfer element circuitry of claim 1 , wherein the first trimming capacitor is coupled to enhance an effect of the cancellation shield winding, and wherein the second trimming capacitor is coupled to enhance an effect of the balance shield winding.

11. The energy transfer element circuitry of claim 1 , wherein the first trimming capacitor is coupled between the cancellation shield winding and the primary winding.

12. The energy transfer element circuitry of claim 1 , wherein when current flows through the energy transfer element circuitry, the cancellation shield winding produces an electrostatic field with an opposite polarity as a net electric field produced by the primary winding, the balance shield winding, and the secondary winding.

13. A power converter, comprising:
energy transfer element circuitry coupled between an input and an output of the power converter, wherein the input of the power converter includes first and second input supply rails, the energy transfer element circuitry including:
a cancellation shield winding wound around an energy transfer element core;
a first trimming capacitor coupled to a first end of the cancellation shield winding to adjust a shield response of the cancellation shield winding, wherein a second end of the cancellation shield winding is unconnected, wherein a first end of the first trimming capacitor is coupled to the first input supply rail, and wherein a second end of the first trimming capacitor is coupled to the first end of the cancellation shield winding;
a primary winding wound around the energy transfer element core;
a balance shield winding wound around the energy transfer element core;
a second trimming capacitor coupled to a second end of the balance shield winding to adjust a shield response of the balance shield winding, wherein a first end of the balance shield winding is unconnected, wherein a second end of the second trimming capacitor is coupled to the second input supply rail, and wherein a first end of the second trimming capacitor is coupled to the second end of the cancellation shield winding; and
a secondary winding wound around the energy transfer element core;

a switch coupled to the primary winding; and
a controller coupled to control switching of the switch to regulate a transfer of energy from the input of the power converter to the output of the power converter in response to a feedback signal representative of the output of the power converter.

14. The power converter of claim 13 , wherein a first end of the primary winding is coupled to the first input supply rail, wherein a second end of the primary winding is coupled to the switch.

15. The power converter of claim 13 , further comprising:
an output rectifier coupled to a first end of the secondary winding;
an output return coupled to a second of the secondary winding; and
an output capacitor coupled to the output rectifier and the output return.

16. The power converter of claim 13 , wherein the balance shield winding comprises copper foil wound over the primary winding.

17. The power converter of claim 13 , wherein the balance shield winding comprises magnet wire wound over the primary winding.

18. The power converter of claim 13 , wherein each layer of the cancellation shield winding, the primary winding, the balance shield winding, and the secondary winding are separated from each other with tape layers.

19. The power converter of claim 13 , wherein the first trimming capacitor is coupled to enhance an effect of the cancellation shield winding, and wherein the second trimming capacitor is coupled to enhance an effect of the balance shield winding.

Assignees

• Power Integrations Inc

Inventors

• Martin Robert A

Classifications

• H02M1/44 Primary

  Circuits or arrangements for compensating for electromagnetic interference in converters or inverters · CPC title

• H02M3/28

  using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC · CPC title

• H01F27/289

  with auxiliary windings (for pancake coils H01F27/2871) · CPC title

• H01F27/42

  Circuits specially adapted for the purpose of modifying, or compensating for, electric characteristics of transformers, reactors, or choke coils (circuits for controlling transformers, reactors or choke coils, for the purpose of obtaining a desired output H02P13/00; impedance networks H03H) · CPC title

• H02M3/33592 Primary

  having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer · CPC title