Apparatus and methods for filter bypass for radio frequency front-ends

Patent metadata

Field	Value
Publication number	US-10103772-B2
Application number	US-201715671997-A
Country	US
Kind code	B2
Filing date	Aug 8, 2017
Priority date	Aug 10, 2016
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

Apparatus and methods for filter bypass for radio frequency front-ends are provided. In certain configurations, filter connectivity of a front-end is changed as a function of automatic gain control (AGC) in a receive path. For example, lossy filtering can be bypassed when signal conditions and the surrounding interference environment allow. In certain implementations, an additional gain state is added to the AGC in the form of a bypass of the filtering. Thus, receiver gain and noise figure are greatly improved while the linearity and susceptibility to blockers is degraded.

First claim

What is claimed is:

1. A mobile device comprising:
an antenna;
a front-end system including a signal path configured to generate a radio frequency signal based on processing a received signal from the antenna, the front-end system including a blocker filter for providing blocker filtering and a low noise amplifier; and
a transceiver configured to receive the radio frequency signal and to operate the front-end system in a selected mode chosen from a plurality of modes, the transceiver further configured to change an amount of blocker filtering provided by the front-end system based on the selected mode, the plurality of modes including a first mode in which the blocker filter and the low noise amplifier are bypassed, a second mode in which the low noise amplifier is before the blocker filter in the signal path, and a third mode in which the blocker filter is before the low noise amplifier in the signal path.

2. The mobile device of claim 1 wherein the transceiver includes a blocker detector configured to detect a blocker signal level based from the radio frequency signal, the transceiver further configured to choose the selected mode based on the detected blocker signal level.

3. The mobile device of claim 1 wherein the blocker filter is tunable, the transceiver further configured to tune the blocker filter based on the selected mode.

4. The mobile device of claim 1 wherein the transceiver is further configured to change at least one of a bias or a gain of the low noise amplifier based on the selected mode.

5. The mobile device of claim 1 wherein the transceiver includes an automatic gain control system configured to choose the selected mode.

6. The mobile device of claim 5 wherein the automatic gain control system includes a table of gain settings, wherein one or more gain settings of the table indicate activation of a receive bypass path that bypasses the blocker filter and the low noise amplifier.

7. The mobile device of claim 1 wherein the plurality of modes further includes a fourth mode in which the blocker filter is included in the signal path and the low noise amplifier is bypassed.

8. The mobile device of claim 7 wherein the plurality of modes further includes a fifth mode in which the low noise amplifier is included in the signal path and the blocker filter is bypassed.

9. The mobile device of claim 1 wherein the front-end system includes an input terminal configured to receive the received signal, an output terminal configured to output the radio frequency signal, a plurality of switches controlled by the transceiver to set the selected mode.

10. The mobile device of claim 9 wherein the plurality of switches includes a first switch connected between the output terminal and an output of the blocker filter, a second switch connected between the output terminal and an output of the low noise amplifier, and a third switch connected between the output terminal and the input terminal.

11. The mobile device of claim 10 wherein the plurality of switches further includes a fourth switch connected between the input terminal and an input to the low noise amplifier, a fifth switch connected between the input terminal and an input to the blocker filter, a sixth switched connected between the output of the low noise amplifier and the input to the blocker filter, and a seventh switch connected between the input of the low noise amplifier and the output of the blocker filter.

12. A front-end system for a radio frequency communication device, the front-end system comprising:
a low noise amplifier;
a blocker filter for providing blocker filtering of a signal received by an antenna;
a plurality of switches configured to control connectivity of the blocker filter and the low noise amplifier in a signal path; and
a controller configured to control the plurality of switches to operate the front-end system in a selected mode chosen from a plurality of modes, and to change an amount of blocker filtering provided to the signal based on the selected mode, the plurality of modes including a first mode in which the blocker filter and the low noise amplifier are bypassed, a second mode in which the low noise amplifier is before the blocker filter in the signal path, and a third mode in which the blocker filter is before the low noise amplifier in the signal path.

13. The front-end system of claim 12 wherein the controller is further configured to change at least one of a bias or a gain of the low noise amplifier based on the selected mode.

14. The front-end system of claim 12 wherein the plurality of modes further includes a fourth mode in which the blocker filter is included in the signal path and the low noise amplifier is bypassed.

15. The front-end system of claim 14 wherein the plurality of modes further includes a fifth mode in which the low noise amplifier is included in the signal path and the blocker filter is bypassed.

16. The front-end system of claim 12 wherein the plurality of switches includes a first switch connected between an output terminal and an output of the blocker filter, a second switch connected between the output terminal and an output of the low noise amplifier, a third switch connected between the output terminal and an input terminal, a fourth switch connected between the input terminal and an input to the low noise amplifier, a fifth switch connected between the input terminal and an input to the blocker filter, a sixth switched connected between the output of the low noise amplifier and the input to the blocker filter, and a seventh switch connected between the input of the low noise amplifier and the output of the blocker filter.

17. A method of receiving signals in user equipment of a wireless communication network, the method comprising:
providing a received signal from an antenna to a front-end system that includes a blocker filter and a low noise amplifier;
generating a radio frequency signal by processing the received signal using a signal path of the front-end system;
operating the front-end system in a selected mode chosen from a plurality of modes including a first mode in which the blocker filter and the low noise amplifier are bypassed, a second mode in which the low noise amplifier is before the blocker filter in the signal path, and a third mode in which the blocker filter is before the low noise amplifier in the signal path; and
changing an amount of blocker filtering provided by the front-end system based on the selected mode.

18. The method of claim 17 further comprising detecting a blocker signal level of the antenna, and choosing the selected mode based on the detected blocker signal level.

19. The method of claim 17 wherein the plurality of modes further includes a fourth mode in which the blocker filter is included in the signal path and the low noise amplifier is bypassed.

20. The method of claim 19 wherein the plurality of modes further includes a fifth mode in which the low noise amplifier is included in the signal path and the blocker filter is bypassed.

Assignees

• Skyworks Solutions Inc

Inventors

• Pehlke David Richard
• Wloczysiak Stephane Richard Marie

Classifications

• H04B1/40 Primary

  Circuits · CPC title

• H03F3/72

  Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal · CPC title

• H03F3/19

  with semiconductor devices only · CPC title

• H03F2203/7239

  the gated amplifier being switched on or off by putting into parallel or not, by choosing between amplifiers and shunting lines by one or more switch(es) · CPC title

• H03F2200/451

  the amplifier being a radio frequency amplifier · CPC title