Transformer of the balanced-unbalanced type

Patent metadata

Field	Value
Publication number	US-9571060-B2
Application number	US-201213557593-A
Country	US
Kind code	B2
Filing date	Jul 25, 2012
Priority date	Jul 28, 2011
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A transformer of the balanced-unbalanced type includes a primary inductive circuit and a secondary inductive circuit housed inside an additional inductive winding connected in parallel to the terminals of the secondary circuit and inductively coupled with the primary circuit and the secondary circuit.

First claim

That which is claimed:

1. A transformer of the balanced-unbalanced type comprising:
a plurality of metal levels having a primary inductive circuit and a secondary inductive circuit formed thereon, the primary inductive circuit having a first port; and
an additional inductive winding having a pair of differential ports and an innermost turn directly surrounding a portion of an outermost turn of each of the primary and secondary inductive circuits, the additional inductive winding coupled in parallel to terminals of the secondary inductive circuit, and inductively coupled with the primary inductive circuit and the secondary inductive circuit.

2. The transformer according to claim 1 , wherein the additional inductive winding is symmetrical and coplanar with the primary inductive circuit and the secondary inductive circuit.

3. The transformer according to claim 1 , wherein the additional inductive winding is formed on the plurality of metal levels in an interlaced and stacked manner.

4. The transformer according to claim 1 , further comprising a semiconductor substrate supporting the primary inductive circuit, the secondary inductive circuit and the additional inductive winding.

5. A wireless communication circuit comprising:
an antenna;
a processor; and
a transformer coupled between the antenna and the processor, and comprising
a plurality of metal levels having a primary inductive circuit and a secondary inductive circuit formed thereon, the primary inductive circuit having a first port, and
an additional inductive winding having a pair of differential ports and an innermost turn directly surrounding a portion of an outermost turn of each of the primary and secondary inductive circuits, the additional inductive winding coupled in parallel to terminals of the secondary inductive circuit, and inductively coupled with the primary inductive circuit and the secondary inductive circuit.

6. The transformer according to claim 5 , wherein the additional inductive winding is symmetrical and coplanar with the primary inductive circuit and the secondary inductive circuit.

7. The transformer according to claim 5 , further comprising capacitors respectively connected between terminals of the additional inductive winding and the terminals of the secondary inductive circuit; wherein the additional inductive winding includes a middle point configured to be coupled to a voltage source.

8. A method of making a transformer of the balanced-unbalanced type, the method comprising:
forming a primary inductive circuit and a secondary inductive circuit on a plurality of metal levels, the primary inductive circuit having a first port; and
surrounding a portion of an outermost turn of each of the primary and secondary inductive circuits directly with an innermost turn of an additional inductive winding coupled in parallel to terminals of the secondary inductive circuit, and inductively coupled with the primary inductive circuit and the secondary inductive circuit.

9. The method according to claim 8 , wherein the additional inductive winding is symmetrical and coplanar with the primary inductive circuit and the secondary inductive circuit.

10. The method according to claim 8 , wherein the additional inductive winding is formed on the plurality of metal levels in an interlaced and stacked manner.

11. The method according to claim 8 , further comprising supporting the primary inductive circuit, the secondary circuit and the additional inductive winding on a semiconductor substrate.

12. The method according to claim 8 , further comprising connecting respective capacitors between terminals of the additional inductive winding and the terminals of the secondary inductive circuit; wherein the additional inductive winding includes a middle point configured to be coupled to a voltage source.

Assignees

• Gianesello Frederic
• Pilard Romain
• Durand Cedric
• St Microelectronics Crolles 2 Sas
• St Microelectronics Sa

Inventors

• Gianesello Frederic
• Pilard Romain
• Durand Cedric

Classifications

• H10W20/496

  Capacitor integral with wiring layers · CPC title

• H10W20/497

  Inductive arrangements or effects of, or between, wiring layers · CPC title

• Y10T29/4902

  Electromagnet, transformer or inductor · CPC title

• H03H7/42 Primary

  Networks for transforming balanced signals into unbalanced signals and vice versa, e.g. baluns · CPC title

• H01F27/2804

  Printed windings · CPC title