Cooperative tunable RF filters

• US 9,628,045 B2
• Filed: 08/01/2014
• Issued: 04/18/2017
• Est. Priority Date: 08/01/2013
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Inventors: Leipold, Dirk Robert Walter, Maxim, George, Scott, Baker, Khlat, Nadim, Rao, Jayanti Jaganatha
• Primary Examiner(s): Jones, Stephen E
• Assistant Examiner(s): PATEL, RAKESH BHASKARBHAI
• Application Number:
  US14/449,913
• Publication Number:
  US 20150035617A1
• Time in Patent Office: 991 Days
• Field of Search: 333132, 333 171, 333174, 333175, 370270
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• CPC Class Codes: H03F 2200/267 A capacitor based passive circuit, e.g. filter, being used in an amplifying circuit
• CPC Class Codes: H03F 2200/391 the output circuit of an amplifying stage comprising an LC-network
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2203/7209 the gated amplifier being switched from a first band to a second band
• CPC Class Codes: H03F 3/193 with field-effect devices H03F3/195 takes precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/68 Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H03H 2210/012 Centre frequency; Cut-off frequency
• CPC Class Codes: H03H 2210/025 Capacitor
• CPC Class Codes: H03H 2210/04 Filter calibration method
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H03H 7/09 Filters comprising mutual inductance
• CPC Class Codes: H03H 7/1775 Parallel LC in shunt or branch path H03H7/1791 takes precedence
• CPC Class Codes: H03H 7/465 having variable circuit topology, e.g. including switches

Abstract

RF communications circuitry, which includes a first tunable RF filter and a second tunable RF filter, is disclosed. The first tunable RF filter is coupled to the second tunable RF filter. The RF communications circuitry operates in one of a first operating mode and a second operating mode. During the first operating mode, the second tunable RF filter receives and filters an upstream RF signal to provide a filtered RF signal. Further, during the first operating mode, the first tunable RF filter augments a frequency response of the second tunable RF filter.

Claims

1. An apparatus configured to operate in one of a first operating mode and a second operating mode, and comprising a first RF filter structure having a connection node and a common connection node, wherein the first RF filter structure comprises:

a shunt RF switch coupled between the connection node and a ground;

a first tunable RF filter coupled to a second tunable RF filter and configured to during the second operating mode, not augment a frequency response of the second tunable RF filter; and

the second tunable RF filter, which is coupled between the connection node and the common connection node, is configured to during the first operating mode, receive and filter an upstream RF signal to provide a filtered RF signal, such that the first tunable RF filter is configured to augment a frequency response of the second tunable RF filter.

2. The apparatus of claim 1 further comprising control circuitry, which is configured to select the one of the first operating mode and the second operating mode.

3. The apparatus of claim 1 wherein the first tunable RF filter is coupled to the second tunable RF filter via the common connection node.

4. The apparatus of claim 1 wherein during the second operating mode, the second tunable RF filter is further configured to receive and filter the upstream RF signal to provide the filtered RF signal.

5. The apparatus of claim 1 wherein during the second operating mode, the first tunable RF filter is further configured to be disabled.

6. The apparatus of claim 5 wherein during the second operating mode, the second tunable RF filter is further configured to be disabled.

7. The apparatus of claim 1 wherein during the second operating mode, the second tunable RF filter is further configured to be disabled.

8. The apparatus of claim 1 wherein the filtered RF signal is a filtered RF receive signal.

9. The apparatus of claim 1 wherein during the first operating mode, the shunt RF switch is configured to be in a CLOSED state.

10. The apparatus of claim 1 wherein during the second operating mode, the shunt RF switch is configured to be in an OPEN state.

11. The apparatus of claim 1 wherein the first RF filter structure further has a second connection node and further comprises a second shunt RF switch coupled between the second connection node and the ground.

12. The apparatus of claim 11 wherein the first tunable RF filter is further coupled between the second connection node and the common connection node.

13. The apparatus of claim 11 wherein during the first operating mode, the second shunt RF switch is configured to be in an OPEN state.

14. The apparatus of claim 11 wherein during the second operating mode, the second shunt RF switch is configured to be in a CLOSED state.