FRONT END MODULE WITH COMPENSATING DUPLEXER

• US 20110299437A1
• Filed: 11/15/2010
• Published: 12/08/2011
• 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
• Granted Patent: US 8,792,836 B2
• Time in Patent Office: Days
• US Class Current: 370/278
• 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 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence
• CPC Class Codes: H04B 1/582 with automatic balancing

Abstract

A front end module includes a duplexer and a balancing network. The duplexer includes a compensation circuit and a transformer three windings having five nodes. The first node for operably coupling an antenna to the first winding; the second node operable to receive an outbound wireless signal and operably couples the first winding to the second winding; the third node operably couples the second winding to a balancing network; the fourth node operably coupled to output a first signal component corresponding to an inbound wireless signal from the third winding; and the fifth node operably coupled to output a second signal component corresponding to an inbound wireless signal from the third winding. The duplexer provides electrical isolation between the first and second signal components and the outbound wireless signal. The compensation module is operable to compensate the electrical isolation between the first and second signals and the outbound wireless signal.

Claims

1. A front end module comprises:

a duplexer including;

a first winding;

a second winding;

a third winding;

first through fifth nodes, wherein;

the first node for operably coupling an antenna to the first winding;

the second node operable to receive an outbound wireless signal and operably couples the first winding to the second winding;

the third node operably couples the second winding to a balancing network;

the fourth node operably coupled to output a first signal component corresponding to an inbound wireless signal from the third winding; and

the fifth node operably coupled to output a second signal component corresponding to an inbound wireless signal from the third winding, wherein the first and second signal components are electrically isolated from the outbound wireless signal; and

a compensation module operably coupled to at least one of the first, second, and third windings and operable to compensate the electrical isolation between the first and second signals and the outbound wireless signal; and

a balancing network operable to establish an impedance that substantially matches an impedance of the antenna.

2. The front end module of claim 1, wherein the compensation module comprises:

a first compensation capacitor coupled in parallel with a first parasitic capacitance formed between the first and third windings; and

a second compensation capacitor coupled in parallel with a second parasitic capacitance formed between the second and third windings, wherein a sum of capacitance of the first compensation capacitor and the first parasitic capacitance substantially equals a sum of capacitance of the second compensation capacitor and the second parasitic capacitance.

3. The front end module of claim 2 further comprises:

a detection module operably coupled to detect an imbalance between the first and second parasitic capacitances;

a processing module operably coupled to;

determine the capacitances of the first and second compensation capacitors based on the imbalance between the first and second parasitic capacitances;

generate a first capacitance setting based on the determined capacitance of the first compensation capacitor; and

generate a second capacitance setting based on the determined capacitance of the second compensation capacitor;

the first compensation capacitor including a first capacitor network that is set based on the first capacitance setting; and

the second compensation capacitor including a second capacitor network that is set based on the second capacitance setting.

4. The front end module of claim 1 further comprises:

a low noise amplifier operably coupled to amplify the inbound wireless signal, wherein the low noise amplifier includes a common-mode isolation compensation circuit.

5. The front end module of claim 4, wherein the common-mode isolation compensation circuit comprises:

a first capacitor coupled to a first input transistor;

a second capacitor coupled to a second input transistor; and

a common-mode degeneration inductor coupled to a return and a common node of the first and second capacitors.

6. The front end module of claim 1, wherein the duplexer comprises:

the first and second windings formed on a first two thick metal layers of a substrate; and

the third winding is formed on a second two thick metal layers of a substrate.

7. The front end module of claim 1, wherein the duplexer comprises:

the first and second windings formed on a first thick metal layer of a substrate; and

the third winding is formed on at least a second thick metal layers of a substrate, wherein the first and second windings have an approximate ninety degree rotation with respect to the third winding.

8. A radio front end comprises:

a power amplifier operably coupled to amplify an up-converted signal to produce an outbound wireless signal;

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

a balancing network operably coupled to the duplexer and operable to establish an impedance that substantially matches an impedance of the antenna;

a low noise amplifier operably coupled to amplify the inbound wireless signal, wherein the low noise amplifier includes a common-mode isolation compensation circuit that compensates for degradation of common-mode isolation caused parasitic capacitance of the duplexer.

9. The front end module of claim 8, wherein the common-mode isolation compensation circuit comprises:

a first capacitor coupled to a first input transistor;

a second capacitor coupled to a second input transistor; and

a common-mode degeneration inductor coupled to a return and a common node of the first and second capacitors.

10. The front end module of claim 8 further comprises:

a compensation module operable to compensate for degradation of the electrical isolation between the first and second signals and the outbound wireless signal caused by parasitic capacitance of the duplexer.

11. The front end module of claim 8, wherein the compensation module comprises:

a first compensation capacitor coupled in parallel with a first parasitic capacitance of the duplexer; and

a second compensation capacitor coupled in parallel with a second parasitic capacitance of the duplexer, wherein a sum of capacitance of the first compensation capacitor and the first parasitic capacitance substantially equals a sum of capacitance of the second compensation capacitor and the second parasitic capacitance.

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

a detection module operably coupled to detect an imbalance between the first and second parasitic capacitances;

a processing module operably coupled to;

determine the capacitances of the first and second compensation capacitors based on the imbalance between the first and second parasitic capacitances;

generate a first capacitance setting based on the determined capacitance of the first compensation capacitor; and

generate a second capacitance setting based on the determined capacitance of the second compensation capacitor;

the first compensation capacitor including a first capacitor network that is set based on the first capacitance setting; and

the second compensation capacitor including a second capacitor network that is set based on the second capacitance setting.

13. The front end module of claim 8 further comprises:

a front end module that includes the power amplifier, the duplexer, and the balancing network; and

a system on a chip module that includes the low noise amplifier.

14. A radio front end comprises:

a power amplifier operably coupled to amplify an up-converted signal to produce an outbound wireless signal;

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

a balancing network operably coupled to the duplexer and operable to establish an impedance that substantially matches an impedance of the antenna; and

a compensation module operable to compensate for degradation of the electrical isolation between the first and second signals and the outbound wireless signal caused by parasitic capacitance of the duplexer.

15. The front end module of claim 14, wherein the compensation module comprises:

a first compensation capacitor coupled in parallel with a first parasitic capacitance of the duplexer; and

a second compensation capacitor coupled in parallel with a second parasitic capacitance of the duplexer, wherein a sum of capacitance of the first compensation capacitor and the first parasitic capacitance substantially equals a sum of capacitance of the second compensation capacitor and the second parasitic capacitance.

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

a detection module operably coupled to detect an imbalance between the first and second parasitic capacitances;

a processing module operably coupled to;

determine the capacitances of the first and second compensation capacitors based on the imbalance between the first and second parasitic capacitances;

generate a first capacitance setting based on the determined capacitance of the first compensation capacitor; and

generate a second capacitance setting based on the determined capacitance of the second compensation capacitor;

the first compensation capacitor including a first capacitor network that is set based on the first capacitance setting; and

the second compensation capacitor including a second capacitor network that is set based on the second capacitance setting.