Transformer filter arrangement

Patent metadata

Field	Value
Publication number	US-9853621-B2
Application number	US-201615044466-A
Country	US
Kind code	B2
Filing date	Feb 16, 2016
Priority date	Jul 21, 2011
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A transformer filter arrangement including a transformer having a first winding and a second winding is provided. Both of the first and the second windings are located between an outer border and an inner border, which is inside the outer border. The transformer filter arrangement further includes at least one reactive sub circuit, each including at least one inductor. The first winding of the transformer is divided into a plurality of winding segments. At least a first one of the at least one reactive sub circuit being connected in series with the winding segments of the first winding between two such winding segments, and having at least one of the at least one inductor located inside said inner border.

First claim

What is claimed is:

1. A transformer filter arrangement, comprising:
a transformer having a first winding and a second winding formed by conducting and isolation layers of one of a chip and printed circuit board, winding loops of both the first and the second windings, when considered in a plane of the first winding and the second winding of the transformer, enclose an area of the one of said chip and printed circuit board; and
at least one reactive sub circuit, each comprising:
at least one inductor formed by a loop in the corresponding plane of one of the first winding and the second winding, and
a capacitor connected one of in series and in parallel with the at least one inductor;

the first winding of the transformer being divided into a plurality of winding segments;
at least a first one of the at least one reactive sub circuit:
being connected in series with the plurality of winding segments of the first winding between two such winding segments, and
having at least one of the at least one inductor located in said area; and

the transformer and the at least one reactive sub circuit being tuned such that the transformer filter arrangement is configured to pass signals at a fundamental frequency and to suppress signals at least at one interfering frequency.

2. The transformer filter arrangement of claim 1 , wherein each inductor of said at least a first one of the at least one reactive sub circuit is located in said area.

3. The transformer filter arrangement of claim 2 , wherein each of the at least one reactive sub circuit:
is connected in series with the plurality of winding segments of the first winding between two such winding segments; and
has at least one inductor located in said area.

4. The transformer filter arrangement of claim 1 , wherein the second winding of the transformer is divided into a plurality of winding segments;
at least a second one of the at least one reactive sub circuit:
being connected in series with the plurality of winding segments of the second winding between two such winding segments, and
having at least one of at least one inductor of the second one of the at least one reactive sub circuit located in said area.

5. The transformer filter arrangement of claim 4 , wherein each inductor of said at least a second one of the at least one reactive sub circuit is located in said area.

6. The transformer filter arrangement of claim 4 , wherein each of the at least one reactive sub circuit:
is one of connected in series with the plurality of winding segments of the first winding between two such winding segments and connected in series with the winding segments of the second winding between two such winding segments; and
has at least one of the at least one inductor located in said area.

7. The transformer filter arrangement of claim 1 , wherein the transformer filter arrangement is part of a radio transmitter circuit.

8. The transformer filter arrangement of claim 1 , wherein said at least one interfering frequency includes at least one harmonic of the fundamental frequency.

9. The transformer filter arrangement of claim 8 , wherein the at least one harmonic includes at least one odd order harmonic.

10. The transformer filter arrangement of claim 9 , wherein the at least one odd order harmonic includes a third harmonic.

11. The transformer filter arrangement of claim 8 , wherein the transformer filter arrangement has a notch-filter characteristic with notches at the at least one harmonic frequency.

12. The transformer filter arrangement of claim 1 , further comprising at least one additional filtering circuit connected to at least one terminal of at least one of the first and the second winding.

13. The transformer filter arrangement of claim 1 , wherein the transformer filter arrangement is a balun arrangement and the transformer is a balun transformer.

14. The transformer filter arrangement of claim 1 , wherein the transformer filter arrangement is part of an integrated circuit.

15. The transformer filter arrangement of claim 1 , wherein the transformer filter arrangement is part of a radio receiver circuit.

16. The transformer filter arrangement of claim 1 , wherein each of the at least one reactive sub circuit:
is connected in series with the plurality of winding segments of the first winding between two such winding segments; and
has at least one inductor located in said area.

17. The transformer filter arrangement of claim 16 , wherein each inductor of each at least one reactive sub circuit is located in said area.

18. A radio communication apparatus comprising at least one transformer filter arrangement, each transformer filter arrangement including:
a transformer having a first winding and a second winding formed by conducting and isolation layers of one of a chip and printed circuit board, winding loops of both the first and the second windings, when considered in a plane of the first winding and the second winding of the transformer, enclose an area of the one of said chip and printed circuit board; and
at least one reactive sub circuit, each comprising:
at least one inductor formed by a loop in the corresponding plane of one of the first winding and the second winding, and
a capacitor connected one of in series and in parallel with the at least one inductor;

the first winding of the transformer being divided into a plurality of winding segments;
at least a first one of the at least one reactive sub circuit:
being connected in series with the plurality of winding segments of the first winding between two such winding segments, and
having at least one of the at least one inductor located in said area; and

the transformer and the at least one reactive sub circuit being tuned such that the transformer filter arrangement is configured to pass signals at a fundamental frequency and to suppress signals at least at one interfering frequency.

19. The radio communication apparatus of claim 18 , wherein the transformer is part of at least one of an integrated circuit, radio receiver circuit and radio transmitter circuit.

20. The radio communication apparatus of claim 19 , wherein the radio communication apparatus is one of a wireless data modem, a mobile telephone and a radio base station.

Assignees

• ERICSSON TELEFON AB L M (publ)

Inventors

• Andersson Stefan
• Mu Fenghao
• Wernehag Johan

Classifications

• H03H7/09 Primary

  Filters comprising mutual inductance · CPC title

• H03H7/425

  Balance-balance networks · CPC title

• H03H7/1758

  Series LC in shunt or branch path (H03H7/1791 takes precedence) · CPC title

• H03H7/38

  Impedance-matching networks · CPC title

• H01P1/212

  suppressing or attenuating harmonic frequencies (H01P1/215 takes precedence) · CPC title