Switchable transformer with embedded switches inside the windings

• US 8,519,814 B2
• Filed: 09/30/2011
• Issued: 08/27/2013
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Feng, Lei, Chu, Chi D., Sadhwani, Ram
• Primary Examiner(s): Musleh, Mohamad
• Assistant Examiner(s): LIAN, MANG TIN BIK
• Application Number:
  US13/250,934
• Publication Number:
  US 20130082810A1
• Time in Patent Office: 697 Days
• Field of Search: 336138-150, 336/200, 336/232, 336/170, 336/180, 336/182, 455/121, 455/292, 455/129, 455/280, 455/338, 333/32, 333/25, 333/132, 333/26, 361/736, 361/749, 257/531
• US Class Current: 336/145
• CPC Class Codes: H01F 2021/125 Printed variable inductor with taps, e.g. for VCO
• CPC Class Codes: H01F 21/12 discontinuously variable, e.g. tapped
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 29/02 with tappings on coil or winding; with provision for rearrangement or interconnection of windings

Abstract

A switchable transformer architecture is disclosed. The switchable transformer includes a primary winding, a secondary winding, and a tertiary winding, in which either the secondary winding or the tertiary winding establish a signal path to the primary winding, based on the position of switches, enabling transmission to either of two blocks sharing the transformer. The transformer architecture achieves high isolation between sharing blocks and low loss on the signal path.

Claims

1. A transformer, comprising:

a primary winding coupled to a first port;

a secondary winding coupled to a second port, the secondary winding comprising a first segment, a second segment, a third segment, a fourth segment, and a secondary winding switch, wherein;

the first segment comprises an S1_A end and an S1_B end, wherein the S1_A end is coupled to the secondary winding switch and the S1_B end is coupled to the second port;

the second segment comprises an S2_A end and an S2_B end, wherein the S2_A end is coupled to the secondary winding switch;

the third segment comprises an S3_A end and an S3_B end, wherein the S3_A end is coupled to the secondary winding switch and the S3_B end is coupled to the S2_B end of the second segment; and

the fourth segment comprises an S4_A end and an S4_B end, wherein the S4_A end is coupled to the secondary winding switch and the S4_B end is coupled to the second port;

wherein the secondary winding switch is;

turned on when S1_A is coupled to S2_A and S3_A is coupled to S4_A; and

turned off when S1_A is coupled to S3_A and S4_A is coupled to S2_A; and

a tertiary winding coupled to a third port, the tertiary winding comprising four tertiary segments and a tertiary winding switch wherein the tertiary winding switch is disposed between the four tertiary segments;

wherein a current is induced in the secondary winding and minimal current is induced in the tertiary winding when the secondary winding switch is turned on and the tertiary winding switch is turned off.

2. The transformer of claim 1, wherein the current is induced in the tertiary winding and minimal current is induced in the secondary winding when the tertiary winding switch is turned on and the secondary winding switch is turned off.

3. The transformer of claim 1, wherein the first port is coupled to a source, and the source is an antenna.

4. The transformer of claim 1, wherein the second port is coupled to a first load and the first load is a transmitter.

5. The transformer of claim 1, wherein the third port is coupled to a second load and the second load is a receiver.

6. The transformer of claim 1, wherein the secondary winding switch is disposed at the S1_A end of the first segment, the S2_A end of the second segment, the S3_A end of the third segment, and the S4_A end of the fourth segment.

7. The transformer of claim 6, wherein the secondary winding switch is turned on when the S1_A end of the first segment is coupled to the S2_A end of the second segment and the S3_A end of the third segment is coupled to the S4_A end of the fourth segment.

8. The transformer of claim 1, wherein the tertiary winding comprises a fifth segment, a sixth segment, seventh a segment, and an eighth segment, wherein:

the fifth segment comprises an S5_A end and an S5_B end, wherein the S5_A end is coupled to the tertiary winding switch;

the sixth segment comprises an S6_A end and an S6_B end, wherein the S6_A end is coupled to the tertiary winding switch and the S6_B end is coupled to the S5_B end of the fifth segment;

the seventh segment comprises an S7_A end and an S7_B end, wherein the S7_A end is coupled to the tertiary winding switch and the S7_B end is coupled to the third port; and

the eighth segment comprises an S8_A end and an S8_B end, wherein the S8_A end is coupled to the tertiary winding switch and the S8_B end is coupled to the third port.

9. The transformer of claim 8, wherein the tertiary winding switch is turned off when the S5_A end of the fifth segment is coupled to the S7_A end of the seventh segment and the S6_A end of the sixth segment is coupled to the S8_A end of the eighth segment.

10. A three-port transformer comprising:

a first port coupled to a primary winding, the primary winding comprising at least a single turn;

a second port coupled to a secondary winding, the secondary winding comprising at least two turns, an outer secondary turn and an inner secondary turn, wherein a secondary winding switch is disposed between the outer secondary turn and the inner secondary turn, the secondary winding switch further comprising a first connection point, a second connection point, a third connection point, and a fourth connection point, wherein;

the second connection point couples to the first connection point when the secondary winding switch is turned on;

the second connection point couples to the fourth connection point when the secondary winding switch is turned off;

the third connection point couples to the fourth connection point when the secondary winding switch is turned on;

the third connection point couples to the first connection point when the secondary winding switch is turned off;

wherein the first connection point does not ever couple to the fourth connection point, and the second connection point does not ever couple to the third connection point;

a tertiary port coupled to a tertiary winding, the tertiary winding comprising at least two turns, an outer tertiary turn and an inner tertiary turn, wherein a tertiary winding switch is disposed between the outer tertiary turn and the inner tertiary turn;

wherein the secondary winding has a high coupling coefficient with the primary winding when the secondary switch is turned on and the tertiary switch is turned off.

11. The three-port transformer of claim 10, wherein a signal transmitted from the first port is received by the second port and a second signal transmitted from the second port is received by the first port.

12. The three-port transformer of claim 10, wherein the tertiary winding has a high coupling coefficient with the primary winding when the tertiary switch is turned on and the secondary winding switch is turned off.

13. The three-port transformer of claim 11, wherein a signal transmitted from the first port is received by the third port and a second signal transmitted from the third port is received by the first port.

14. The three-port transformer of claim 10, wherein the first port is coupled to an antenna.

15. The three-port transformer of claim 10, wherein the second port is coupled to a transmitter.

16. The three-port transformer of claim 10, wherein the third port is coupled to a receiver.

17. A transformer, comprising:

a primary winding coupled to an antenna, the primary winding comprising N turns for integer N;

a secondary winding coupled to a transmitter, the secondary winding comprising 2N turns, wherein a secondary winding switch is coupled between an N^th turn of the secondary winding and a (N+1)^th turn; and

a tertiary winding coupled to a receiver, the tertiary winding comprising 2N turns, wherein a tertiary winding switch comprising four connection points is coupled between an N^th turn of the tertiary winding and a (N+1)^th turn, the tertiary winding switch further comprising;

an on position in which a first connection point is coupled to a second connection point and a third connection point is coupled to a fourth connection point; and

an off position in which the first connection point is coupled to the third connection point and the second connection point is coupled to the fourth connection point;

wherein the second connection point of the tertiary winding switch is never coupled to the fourth connection point;

wherein the transmitter is turned on and the receiver is turned off when the secondary winding switch is turned on and the tertiary winding switch is turned off.

18. The transformer of claim 17, the secondary winding switch further comprising four connection points, wherein:

the secondary winding switch is in an on position when a fifth connection point is coupled to a sixth connection point and a seventh connection point is coupled to an eighth connection point; and

the secondary winding switch is in an off position when the fifth connection point is coupled to the seventh connection point and the sixth connection point is coupled to the eighth connection point;

wherein the sixth connection point of the secondary winding switch is never coupled to the eighth connection point.

19. The transformer of claim 17, wherein the secondary winding switch is turned off when the tertiary winding switch is turned on.

20. The transformer of claim 19, wherein the receiver is turned on and the transmitter is turned off.