Transformer-based multi-band RF front-end architecture

• US 20060270377A1
• Filed: 05/25/2005
• Published: 11/30/2006
• Est. Priority Date: 05/25/2005
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Marholev, Bojko F., Castaneda, Jesus, Bhatti, Iqbal
• Granted Patent: US 7,526,256 B2
• Time in Patent Office: Days
• US Class Current: 455/333
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

An apparatus and method for allowing two different signal paths to be coupled to a multi-tap transformer balun. The multi-tap transformer has a first port, which is coupled to a single antenna, and two or more differential secondary ports. Each port has one or more taps, which are optimized separately for each of the signal paths, allowing each of the two or more signal paths to operate in different frequency bands. Use of the method of the invention can decrease the number of external components and integrated circuit package pins, and reduce the area required for each signal path on an integrated circuit die, a printed circuit board, or the like.

Claims

1. A communication system, comprising:

an antenna;

a receiver module operable to receive an inbound radio frequency (RF) signal;

a transmitter module operable to generate an outbound RF signal; and

an on-chip multiple tap transformer balun operably coupled to said antenna, said receiver module and said transmitter module, said transformer balun being operable to receive said inbound RF signal from said antenna; and

further operable to provide said outbound RF signal to said antenna;

wherein the transformer balun comprises;

a primary side coupled to said antenna; and

a secondary side, comprising first and second ports, coupled to first and second signal paths, respectively.

2. The communication system of claim 1, wherein said primary side is coupled to said antenna in a single-ended configuration

3. The communication system of claim 1, wherein said first and second ports are tuned independently.

4. The communication system of claim 3, wherein said first and second signal paths operate in different frequency bands.

5. The communication system of claim 1, wherein said primary side is on a first layer of an integrated circuit and said secondary side is on second layer of an integrated circuit.

6. The communication system of claim 5, wherein said on-chip multiple tap transformer balun comprises:

first winding on a first layer of an integrated circuit, wherein the first winding is operably coupled for a single-ended signal;

first portion of a second winding on a second layer of the integrated circuit, wherein a first node of the first portion of the second winding is operably coupled for a first leg of a first differential signal, wherein a second node of first portion of the second winding is operably coupled to a reference potential, and wherein a tap of the first portion of the second winding is operably coupled for a first leg of a second differential signal; and

second portion of the second winding on the second layer, wherein a first node of the second portion of the second winding is operably coupled for a second leg of the first differential signal, wherein a second node of the second portion of the second winding is operably coupled to the reference potential, wherein a tap of the second portion of the second winding is operably coupled for a second leg of the second differential signal, wherein the second portion of the second winding is substantially symmetrical to the first portion of the second winding, and wherein the tap of the first portion of the second winding is substantially symmetrical to the tap of the second portion of the second winding.

7. The on-chip multiple tap transformer balun of claim 1 further comprises a shunt winding on a third layer of the integrated circuit, wherein the shunt winding is connected in parallel to with the second winding.

8. The on-chip multiple tap transformer balun of claim 1, wherein the second winding further comprises:

a rectangular octagonal shape having a first dimension lengthened with respect to a square octagonal reference shape and having a second dimension shortened with respect to the square octagonal reference shape, wherein area of the rectangular octagonal shape is similar to area of the square octagonal reference shape.

9. A method of balancing RF signals in a communication system, comprising:

operably coupling a transformer balun to an antenna and to a transceiver module; and

using said transformer balun to provide impedance matching for RF signals communicated between said antenna and said transceiver module;

wherein the transformer balun comprises;

a primary side coupled to said antenna; and

a secondary side, comprising first and second ports, coupled to first and second signal paths, respectively.

10. The method of claim 9, wherein said primary side is coupled to said antenna in a single-ended configuration

11. The method of claim 9, wherein said first and second ports are tuned independently.

12. The method of claim 11, wherein said first and second signal paths operate in different frequency bands.

13. The method of claim 9, wherein said primary side is on a first layer of an integrated circuit and said secondary side is on second layer of an integrated circuit.

14. The method of claim 13, wherein said on-chip multiple tap transformer balun comprises:

first winding on a first layer of an integrated circuit, wherein the first winding is operably coupled for a single-ended signal;

first portion of a second winding on a second layer of the integrated circuit, wherein a first node of the first portion of the second winding is operably coupled for a first leg of a first differential signal, wherein a second node of first portion of the second winding is operably coupled to a reference potential, and wherein a tap of the first portion of the second winding is operably coupled for a first leg of a second differential signal; and

second portion of the second winding on the second layer, wherein a first node of the second portion of the second winding is operably coupled for a second leg of the first differential signal, wherein a second node of the second portion of the second winding is operably coupled to the reference potential, wherein a tap of the second portion of the second winding is operably coupled for a second leg of the second differential signal, wherein the second portion of the second winding is substantially symmetrical to the first portion of the second winding, and wherein the tap of the first portion of the second winding is substantially symmetrical to the tap of the second portion of the second winding.

15. The on-chip multiple tap transformer balun of claim 9 further comprises a shunt winding on a third layer of the integrated circuit, wherein the shunt winding is connected in parallel to with the second winding.

16. The on-chip multiple tap transformer balun of claim 9, wherein the second winding further comprises:

a rectangular octagonal shape having a first dimension lengthened with respect to a square octagonal reference shape and having a second dimension shortened with respect to the square octagonal reference shape, wherein area of the rectangular octagonal shape is similar to area of the square octagonal reference shape.

17. An apparatus for balancing radio frequency (RF) signals, comprising:

a multiple tap transformer balun comprising a primary side and a secondary side, said secondary side comprising first and second ports, coupled to first and second signal paths, respectively;

wherein said first and second ports are tuned independently; and

wherein said first and second signal paths operate in different frequency bands.

18. The apparatus of claim 17, wherein said primary side is on a first layer of an integrated circuit and said secondary side is on second layer of an integrated circuit.

19. The apparatus of claim 18, wherein said multiple tap transformer balun comprises:

first winding on a first layer of an integrated circuit, wherein the first winding is operably coupled for a single-ended signal;

first portion of a second winding on a second layer of the integrated circuit, wherein a first node of the first portion of the second winding is operably coupled for a first leg of a first differential signal, wherein a second node of first portion of the second winding is operably coupled to a reference potential, and wherein a tap of the first portion of the second winding is operably coupled for a first leg of a second differential signal; and

second portion of the second winding on the second layer, wherein a first node of the second portion of the second winding is operably coupled for a second leg of the first differential signal, wherein a second node of the second portion of the second winding is operably coupled to the reference potential, wherein a tap of the second portion of the second winding is operably coupled for a second leg of the second differential signal, wherein the second portion of the second winding is substantially symmetrical to the first portion of the second winding, and wherein the tap of the first portion of the second winding is substantially symmetrical to the tap of the second portion of the second winding.

20. The on-chip multiple tap transformer balun of claim 19 further comprises a shunt winding on a third layer of the integrated circuit, wherein the shunt winding is connected in parallel to with the second winding.