Tunable notch filter and contour tuning circuit

Patent metadata

Field	Value
Publication number	US-9712197-B2
Application number	US-201615247639-A
Country	US
Kind code	B2
Filing date	Aug 25, 2016
Priority date	Aug 28, 2015
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

Aspects of this disclosure relate tuning an impedance presented to a common port of a multi-throw switch and a tunable notch filter coupled to the common port. The impedance presented to the common port can be tuned based on an impedance associated with a throw of the multi-throw switch that is activated. According to embodiments of this disclosure, a shunt inductor in parallel with a tunable capacitance circuit can tune the impedance presented to the common port of the multi-throw switch. In certain embodiments, the tunable notch filter includes a series LC circuit in parallel with a tunable impedance circuit.

First claim

What is claimed is:

1. A radio frequency circuit comprising:
an antenna switch having multiple throws;
a tunable circuit configured to adjust an effective shunt impedance in a signal path from the antenna switch to an antenna port in association with a state of the antenna switch changing;
a tunable notch filter coupled in series between the antenna switch and the antenna port, the tunable notch filter being configured to filter a radio frequency signal propagating between the antenna switch and the antenna port; and
a control circuit configured to set a state of the tunable circuit based on an impedance associated with a trace arranged to route from a duplexer to a throw of the antenna switch that is activated.

2. The radio frequency circuit of claim 1 wherein the tunable notch filter includes a series LC circuit in parallel with a tunable capacitance circuit.

3. The radio frequency circuit of claim 2 wherein the series LC circuit is inductive at frequencies above a resonant frequency of the series LC circuit so as to create a parallel resonance with the tunable capacitance circuit.

4. The radio frequency circuit of claim 2 wherein the control circuit is further configured to control the tunable capacitance circuit such that an effective capacitance in parallel with the series LC circuit corresponds to a frequency of the radio frequency signal.

5. The radio frequency circuit of claim 2 wherein the tunable capacitance circuit and the antenna switch are integrated on a common semiconductor die.

6. The radio frequency circuit of claim 1 wherein the tunable notch filter is arranged to have a frequency response with a notch at a second harmonic frequency of the radio frequency signal.

7. The radio frequency circuit of claim 1 wherein the tunable circuit includes a shunt inductor in parallel with a tunable capacitance circuit.

8. The radio frequency circuit of claim 1 wherein the control circuit is configured to control the tunable circuit so as to provide a first effective shunt impedance when a first throw of the antenna switch is active and to provide a second effective impedance when a second throw of the antenna switch is active.

9. The radio frequency circuit of claim 1 wherein the antenna switch has at least 8 throws.

10. The radio frequency circuit of claim 1 further comprising a trim and control circuit including non-volatile memory storing trim data, the trim and control circuit configured to set a state of the tunable notch filter based on the trim data.

11. A packaged module comprising:
a multi-throw switch including input/output ports and a common port, the multi-throw switch configured to electrically connect a selected one of the input/output ports to the common port;
a tunable circuit configured to adjust an effective shunt impedance coupled to the common port in association with a state of the multi-throw switch changing;
a control circuit configured to set a state of the tunable circuit based on an impedance associated with a trace coupled to a selected throw of the multi-throw switch; and
a tunable notch filter coupled in series in a radio frequency signal path associated with the common port; the multi-throw switch, the tunable circuit, the control circuit, and the tunable notch filter being included within a common package.

12. The packaged module of claim 11 wherein the tunable circuit includes a shunt inductor in parallel with a tunable capacitance circuit.

13. The packaged module of claim 11 wherein the tunable notch filter includes a series LC circuit in parallel with a tunable capacitance circuit.

14. The packaged module of claim 11 wherein the tunable notch filter is configured to provide rejection at a second harmonic of a radio frequency signal propagating between the common port and the tunable notch filter.

15. The packaged module of claim 11 further comprising a trim and control circuit including memory arranged to store trim data, the trim and control circuit configured to set a state of the tunable notch filter based on the trim data.

16. The packaged module of claim 11 further comprising a power amplifier included within the common package.

17. A wireless communication device comprising:
an antenna configured to receive a radio frequency signal;
an antenna switch configured to electrically couple a first radio frequency signal path to the antenna in a first state and to electrically couple a second radio frequency signal path to the antenna in a second state;
a tunable circuit configured to adjust an effective shunt impedance in a signal path from the antenna switch to the antenna in association with a state of the antenna switch changing;
a control circuit configured to control the tunable circuit such that the effective shunt impedance is based on an impedance of the first radio frequency signal path between a duplexer and the antenna switch when the antenna switch is in the first state; and
a tunable notch filter coupled in series between the antenna switch and the antenna.

18. The wireless communication device of claim 17 wherein the tunable circuit is configurable into at least 8 states.

19. The wireless communication device of claim 17 configured as a mobile phone.

20. The wireless communication device of claim 17 further comprising duplexers coupled to the antenna switch by respective traces, the duplexers including the duplexer.

Assignees

• Skyworks Solutions Inc

Inventors

• Ripley David Steven
• Lawrence Edward F
• Ellis Joshua Kawika

Classifications

• H04B1/0458

  Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages (matching circuits in general H03H) · CPC title

• H04B1/18

  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 title

• H03F3/24

  of transmitter output stages · CPC title

• H04B2001/0408

  with power amplifiers · CPC title

• H04B1/1036 Primary

  with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters (H04B1/123 takes precedence; filter circuits H03H) · CPC title