Low-cost receiver using integrated inductors

• US 8,983,417 B2
• Filed: 05/10/2012
• Issued: 03/17/2015
• Est. Priority Date: 01/03/2012
• Status: Active Grant

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Koroglu, Mustafa H., Su, Yu
• Primary Examiner(s): Le, Lana N
• Application Number:
  US13/468,824
• Publication Number:
  US 20130171952A1
• Time in Patent Office: 1,041 Days
• Field of Search: 455130-355
• US Class Current: 455/232.1
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/171 A filter circuit coupled to the output of an amplifier
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 3/19 with semiconductor devices only
• CPC Class Codes: H03F 3/193 with field-effect devices H03F3/195 takes precedence
• CPC Class Codes: H03H 11/1291 Current or voltage controlled filters
• CPC Class Codes: H03H 2210/025 Capacitor
• CPC Class Codes: H03H 2210/033 Continuous
• CPC Class Codes: H03H 7/0169 Intermediate frequency filters
• CPC Class Codes: H03H 7/09 Filters comprising mutual inductance
• CPC Class Codes: H03H 7/46 Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source for use in multiplex transmission systems H04J1/00
• CPC Class Codes: H03J 2200/32 Tuning of tracking filter
• CPC Class Codes: H03J 3/10 Circuit arrangements for fine tuning, e.g. bandspreading
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/16 Circuits
• CPC Class Codes: H04B 1/1638 Special circuits to enhance selectivity of receivers not otherwise provided for resonant circuits H03H
• 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

Abstract

A receiver includes a first amplifier, a first variable capacitor, and an inductance leg. The first amplifier has an input for receiving a radio frequency signal, and an output. The first variable capacitor has a first terminal coupled to the output of the first amplifier, a second terminal coupled to a power supply voltage terminal, and a control terminal for receiving a tuning signal. The inductance leg has a first terminal coupled to the output of the first amplifier, and a second terminal coupled to the power supply voltage terminal. The inductance leg includes a first inductor and has an effective resistance in series with the first inductor, wherein the effective resistance has a value related to an upper frequency threshold to be tuned by the receiver.

Claims

1. A receiver comprising:

a first amplifier having an input for receiving a radio frequency signal, and an output;

a first variable capacitor having a first terminal coupled to the output of the first amplifier, a second terminal coupled to a power supply voltage terminal, and a control terminal for receiving a tuning signal; and

an inductance leg having a first terminal coupled to the output of the first amplifier, and a second terminal coupled to the power supply voltage terminal, the inductance leg including a first inductor and having an effective resistance in series with the first inductor, wherein the effective resistance has a value related to an upper frequency threshold to be tuned by the receiver.

2. The receiver of claim 1 wherein the inductance leg comprises:

a resistor having a first terminal coupled to the output of the first amplifier, and a second terminal coupled to a first terminal of the inductor, wherein the effective resistance of the inductance leg is equal to a resistance of the resistor plus a parasitic resistance of the inductor.

3. The receiver of claim 1, further comprising:

a second amplifier having an input coupled to the output of the first amplifier, and first and second outputs forming a differential signal pair;

a second variable capacitor having a first terminal coupled to the first output of the second amplifier, and a second terminal coupled to the second output of the second amplifier, and a tuning input terminal; and

a second inductor having a first terminal having a first terminal coupled to the first output of the second amplifier, and a second terminal coupled to the second output of the second amplifier.

4. The receiver of claim 1, wherein the first variable capacitor and the first inductor form a filter with a resonant frequency tunable in a range from 50 to 190 MHz.

5. The receiver of claim 1, wherein output of the first amplifier is single-ended.

6. The receiver of claim 1, characterized as being a television receiver.

7. The receiver of claim 1, wherein the first variable capacitor comprises:

a fixed capacitor having a first terminal coupled to the output of the first amplifier, and a second terminal coupled to the power supply voltage terminal.

8. The receiver of claim 1, wherein the first variable capacitor further comprises:

a binary capacitor having a first terminal coupled to the output of the first amplifier, a second terminal coupled to the power supply voltage terminal, and a control terminal for receiving binary coded signal.

9. The receiver of claim 1, wherein the first variable capacitor further comprises:

a thermometer capacitor having a first terminal coupled to the output of the first amplifier, a second terminal coupled to the power supply voltage terminal, and a control terminal for receiving thermometer coded signal.

10. A receiver comprising:

a first amplifier having an input for receiving a radio frequency signal, and an output;

a first variable capacitor having a first terminal coupled to the output of the first amplifier, a second terminal coupled to a power supply voltage terminal, and a control terminal for receiving a tuning signal;

a resistor having a first terminal coupled to the output of the first amplifier, and a second terminal; and

a first inductor having a first terminal coupled to the second terminal of the resistor and a second terminal coupled to the power supply voltage terminal, wherein a resistance of the resistor plus a parasitic resistance of the first inductor form an effective resistance having a value related to an upper frequency threshold to be tuned by the receiver.

11. The receiver of claim 10, further comprising:

a second amplifier having an input coupled to the output of the first amplifier, and first and second outputs forming a differential signal pair;

a second variable capacitor having a first terminal coupled to the first output of the second amplifier, and a second terminal coupled to the second output of the second amplifier, and a tuning input terminal; and

a second inductor having a first terminal having a first terminal coupled to the first output of the second amplifier, and a second terminal coupled to the second output of the second amplifier.

12. The receiver of claim 10, wherein the first variable capacitor, the resistor, and the first inductor have values that provide a resonant frequency tunable in a range from 50 MHz to 190 MHz.