Front end module with active tuning of a balancing network

• US 9,219,596 B2
• Filed: 11/15/2010
• Issued: 12/22/2015
• Est. Priority Date: 06/03/2010
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Mikhemar, Mohyee, Darabi, Hooman
• Primary Examiner(s): Lu, Zhiyu
• Application Number:
  US12/946,050
• Publication Number:
  US 20110299435A1
• Time in Patent Office: 1,863 Days
• US Class Current: 1/1
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/537 A transformer being used as coupling element between two amplifying stages
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03H 19/002 N-path filters
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 1/581 using a transformer
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

A radio front end includes a duplexer, a tunable balancing network, a detector module, and a processing module. The duplexer is operably coupled to an antenna and is operable to provide electrical isolation between an outbound wireless signal and an inbound wireless signal. The tunable balancing network is operably coupled to the duplexer and operable to establish an impedance that substantially matches an impedance of the antenna based on a tuning signal. The detector module is operable to generate an error signal based on an electrical performance characteristic of the duplexer. The processing module is operable to generate the tuning signal based on the error signal.

Claims

1. A radio front end comprises:

a duplexer operably coupled to an antenna, wherein the duplexer is configured to provide electrical isolation between an outbound wireless signal and an inbound wireless signal;

an antenna tuning unit operably coupled to the antenna and the duplexer, wherein the antenna tuning unit is configured to provide a desired antenna matching circuit based on an antenna tuning signal;

a tunable balancing network operably coupled to the duplexer and configured to establish an impedance that substantially matches an impedance of the antenna based on a balancing network tuning signal;

a detector module configured to dynamically generate an error signal based on an electrical performance characteristic of the duplexer, the electrical performance characteristic indicating a common mode offset within the duplexer; and

a processing module configured to generate the antenna tuning signal, the processing module further configured to generate the balancing network tuning signal based on the error signal.

2. The radio front end of claim 1 further comprises:

a sensing circuit configured to sense the electrical performance characteristic of the duplexer.

3. The radio front end of claim 1 further comprises:

a single-ended or differential low noise amplifier operably coupled to the duplexer, wherein the single-ended or differential low noise amplifier amplifies the inbound wireless signal; and

a power amplifier module configured to amplify an outbound up-converted signal to produce the outbound wireless signal.

4. The radio front end of claim 1, wherein the duplexer comprises:

a transformer having a first winding, a second winding, and a third winding, wherein the first winding and the second winding are coupled in series having a first end coupled to the antenna, a second end coupled to the tunable balancing network, and a center tap for receiving the outbound wireless signal, and wherein the third winding is coupled to the detector module.

5. The radio front end of claim 1, wherein the tunable balancing network comprises at least one of:

a tunable resistor-capacitor network;

a tunable inductor-capacitor network;

or

a tunable resistor-inductor-capacitor network.

6. The radio front end of claim 1, wherein the detector module further detects an impedance mismatch within the duplexer by:

a transmit leakage current or voltage of the duplexer.

7. The radio front end of claim 1 further comprises:

a second duplexer operably coupled to a second antenna, wherein the second duplexer is configured to provide electrical isolation between a second outbound wireless signal and a second inbound wireless signal;

a second tunable balancing network operably coupled to the second duplexer and configured to establish an impedance that substantially matches an impedance of the second antenna based on a second balancing network tuning signal;

a second detector module configured to dynamically generate a second error signal based on an electrical performance characteristic of the second duplexer; and

the processing module configured to generate the second balancing network tuning signal based on the second error signal.

8. The radio front end of claim 1 further comprises:

a front end module that includes the duplexer and the tunable balancing network; and

a radio transceiver module that includes the detector module and the processing module.

20. The radio front end of claim 1, wherein the electrical performance characteristic further indicates at least one of an impedance mismatch within the duplexer, a nonlinearity within the duplexer or a frequency dependent response of the duplexer.

9. A front end module comprises:

a duplexer operably coupled to an antenna, wherein the duplexer is configured to provide electrical isolation between an outbound wireless signal and an inbound wireless signal;

an antenna tuning unit operably coupled to the antenna and the duplexer, wherein the antenna tuning unit is configured to provide a desired antenna matching circuit; and

a tunable balancing network operably coupled to the duplexer and configured to dynamically establish an impedance that substantially matches an impedance of the antenna based on a balancing network tuning signal, which is based on an electrical performance characteristic of the duplexer, the electrical performance characteristic indicating a common mode offset within the duplexer.

10. The front end module of claim 9 further comprises:

a sensing circuit configured to sense the electrical performance characteristic of the duplexer.

11. The front end module of claim 9 further comprises:

a power amplifier module configured to amplify an outbound up-converted signal to produce the outbound wireless signal.

12. The front end module of claim 9, wherein the duplexer comprises:

a transformer having a first winding, a second winding, and a third winding, wherein the first and second windings are coupled in series having a first end coupled to the antenna tuning unit, a second end coupled to the tunable balancing network, and a center tap for receiving the outbound wireless signal, and wherein the third winding is coupled to the detector module.

13. The front end module of claim 9, wherein the tunable balancing network comprises at least one of:

a tunable resistor-capacitor network;

a tunable inductor-capacitor network;

or

a tunable resistor-inductor-capacitor network.

14. The front end module of claim 9, wherein the electrical performance characteristic further indicates an impedance mismatch within the duplexer, the impedance mismatch being detected by:

a transmit leakage current or voltage of the duplexer.

15. The front end module of claim 9 further comprises:

a second duplexer operably coupled to a second antenna, wherein the second duplexer is configured to provide electrical isolation between a second outbound wireless signal and a second inbound wireless signal; and

a second tunable balancing network operably coupled to the second duplexer and configured to establish an impedance that substantially matches an impedance of the second antenna based on a second balancing network tuning signal, which is based on an electrical performance characteristic of the second duplexer.

16. A radio transceiver module comprises:

a detector module configured to generate an error signal based on an electrical performance characteristic of a duplexer, the electrical performance characteristic indicating a common mode offset within the duplexer, wherein the duplexer is operably coupled to an antenna and is configured to provide electrical isolation between an outbound wireless signal and an inbound wireless signal; and

a processing module configured to generate a balancing network tuning signal based on the error signal and to provide the balancing network tuning signal to a tunable balancing network, wherein the tunable balancing network is operably coupled to the duplexer and configured to establish an impedance that substantially matches an impedance of the antenna based on the balancing network tuning signal, the processing module further configured to generate an antenna tuning signal and to provide the antenna tuning signal to an antenna tuning unit operably coupled to the antenna and the duplexer, wherein the antenna tuning unit is configured to provide a desired antenna matching circuit based on the antenna tuning signal.

17. The radio transceiver module of claim 16 further comprises:

a single-ended or differential low noise amplifier operably coupled to receive the inbound wireless signal from the duplexer, wherein the single-ended or differential low noise amplifier amplifies the inbound wireless signal.

18. The radio transceiver module of claim 16, wherein the detector module further detects an impedance mismatch within the duplexer by:

a transmit leakage current or voltage of the duplexer.

19. The radio transceiver module of claim 16 further comprises:

a second detector module configured to generate a second error signal based on an electrical performance characteristic of a second duplexer; and

the processing module configured to generate a second balancing network tuning signal based on the second error signal.