Mixer s11 control via sum component termination

Patent metadata

Field	Value
Publication number	US-2019028124-A1
Application number	US-201816040460-A
Country	US
Kind code	A1
Filing date	Jul 19, 2018
Priority date	Jul 20, 2017
Publication date	Jan 24, 2019
Grant date	—

Abstract

A mixer termination circuit for a downconverter mixer includes a diplexer circuit coupled to an output of the downconverter mixer. The diplexer circuit is configured to separately terminate a sum component present in an output signal of the downconverter mixer and a difference component present in the output signal of the downconverter mixer.

First claim

What is claimed is:

1 . A mixer termination circuit for a downconverter mixer, comprising:
a diplexer circuit coupled to an output of the downconverter mixer, the diplexer circuit configured to separately terminate a sum component present in an output signal of the downconverter mixer and a difference component present in the output signal of the downconverter mixer.

2 . The mixer termination circuit of claim 1 , in which the diplexer circuit comprises a termination resistor.

3 . The mixer termination circuit of claim 2 , further comprising an inductor and a capacitor coupled in series with the termination resistor.

4 . The mixer termination circuit of claim 2 , further comprising an inductor and a capacitor coupled in parallel with the termination resistor.

5 . The mixer termination circuit of claim 1 , in which the diplexer circuit comprises a feedback voltage amplifier.

6 . The mixer termination circuit of claim 1 , in which the diplexer circuit comprises a T-network having a series resistor inductor capacitor (RLC) circuit branch including a termination resistor.

7 . The mixer termination circuit of claim 6 , in which the RLC circuit branch is tuned to a frequency of the sum component.

8 . The mixer termination circuit of claim 1 , in which the diplexer circuit comprises a pi-network having an inductor and a capacitor in parallel with a termination resistor, configured to terminate a sum component output of the downconverter mixer at a resonance frequency of the inductor and the capacitor.

9 . The mixer termination circuit of claim 8 , in which the inductor, the capacitor, and the termination resistor are tuned to a frequency of the sum component present in the output signal of the downconverter mixer.

10 . The mixer termination circuit of claim 1 , in which the diplexer circuit comprises an RC filter, including a load resistor RL in parallel with a shunt capacitor, configured to terminate a difference component output of the downconverter mixer at a baseband frequency.

11 . The mixer termination circuit of claim 1 , in which the sum component present in the output signal has a frequency that is a sum of a frequency of a local oscillator (LO) signal of the downconverter mixer and a frequency of a radio frequency (RF) input signal provided to the downconverter mixer.

12 . The mixer termination circuit of claim 1 , in which the difference component present in the output signal has a frequency that is a difference of a frequency of a radio frequency (RF) input signal provided to the downconverter mixer and a frequency of a local oscillator (LO) signal of the downconverter mixer.

13 . The mixer termination circuit of claim 1 , in which the downconverter mixer comprises a mixer-first downconverter, in which a mixer and an amplifier are in a receive chain and an output of the mixer is fed to the amplifier.

14 . The mixer termination circuit of claim 1 , in which the downconverter mixer comprises a current mode mixer or a voltage mode mixer.

15 . The mixer termination circuit of claim 1 , integrated into a mobile RF receiver.

16 . The mixer termination circuit of claim 15 , in which the mobile RF receiver is integrated into an RF integrated circuit (RFIC) system.

17 . A method of controlling an input impedance of a downconverter mixer, comprising:
receiving an output signal from the downconverter mixer at a mixer termination circuit; attenuating a sum component of the output signal using a first branch of the mixer termination circuit; and passing a difference component of the output signal to an output of the mixer termination circuit.

18 . The method of claim 17 , in which the sum component has a frequency that is a sum of a frequency of a local oscillator (LO) signal of the downconverter mixer and a frequency of a radio frequency (RF) input signal provided to the downconverter mixer.

19 . The method of claim 17 , in which the difference component has a frequency that is a difference of a frequency of a radio frequency (RF) input signal provided to the downconverter mixer and a frequency of a local oscillator (LO) signal of the downconverter mixer.

20 . The method of claim 17 , in which attenuating the sum component comprises attenuating using a termination resistor at a sum component output of the downconverter mixer at a resonance frequency.

21 . The method of claim 17 , in which passing the difference component comprises passing the difference component to a difference component output of the downconverter mixer.

22 . The method of claim 17 , in which attenuating the sum component comprises attenuating using a high frequency path through a series resistor inductor capacitor (RLC) branch of a diplexer filter circuit including a termination resistor at a resonance frequency of an inductor and a capacitor of the series RLC branch.

23 . A mixer termination circuit for a downconverter mixer, the mixer termination circuit comprising:
means for attenuating a sum component present in an output signal of the downconverter mixer; and means for passing a difference component present in the output signal of the downconverter mixer.

24 . The mixer termination circuit of claim 23 , in which the downconverter mixer comprises a mixer-first downconverter, in which a mixer and an amplifier are in a receive chain and an output of the mixer is coupled to an input of the amplifier.

25 . The mixer termination circuit of claim 23 , in which the downconverter mixer comprises a current mode mixer or a voltage mode mixer.

26 . The mixer termination circuit of claim 23 , integrated into a mobile RF receiver.

27 . The mixer termination circuit of claim 26 , in which the mobile RF receiver is integrated into an RF integrated circuit system.

28 . The mixer termination circuit of claim 23 , in which the sum component present in the output signal has a frequency that is a sum of a frequency of a local oscillator (LO) signal of the downconverter mixer and a frequency of a radio frequency (RF) input signal provided to the downconverter mixer.

29 . The mixer termination circuit of claim 23 , in which the difference component present in the output signal has a frequency that is a difference of a frequency of a radio frequency (RF) input signal provided to the downconverter mixer and a frequency of a local oscillator (LO) signal of the downconverter mixer.

Assignees

• Qualcomm Inc

Inventors

• Summers Andrew Gordon

Classifications

• H04B1/04

  Circuits · CPC title

• H04B1/006 Primary

  using switches for selecting the desired band (H04B1/0057 takes precedence) · CPC title

• H04B1/18 Primary

  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

• H04B1/0028

  wherein the AD/DA conversion occurs at baseband stage · CPC title

• H04B1/12

  Neutralising, balancing, or compensation arrangements · CPC title