Voltage-Mode Harmonic-Rejection Mixer With Transconductor Summation

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Solution Overview

Problem

Conventional harmonic-rejection mixers are area-inefficient and unable to operate effectively in voltage mode, generating undesirable harmonics and exhibiting non-linearity, which complicates RF transceiver design in wireless communication systems.

Innovation Solution

A voltage mode harmonic-rejection mixer (HRM) is designed with two mixers configured to receive phase-shifted baseband and local oscillator signals, utilizing transconductors to convert voltage mode signals to current mode, allowing for efficient operation and harmonic cancellation without area-inefficient transformers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional harmonic-rejection mixers are used, then harmonic rejection is achieved, but the circuit occupies excessive die area due to electromagnetic components

Engineering Contradiction:

Improveharmonic rejectionVSAvoiddie area

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent replaces electromagnetic components (transformers, inductors) with a voltage-mode circuit implementation using transistors and capacitors. This substitution eliminates the need for area-consuming electromagnetic components while maintaining the harmonic rejection function through voltage-mode signal processing and phase cancellation techniques

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating mode from current-mode to voltage-mode, and modifies the circuit topology to use capacitive coupling and voltage summation instead of transformer-based current summation. This parameter change enables area-efficient implementation while preserving the harmonic rejection mechanism

Inventive Principle:

Principle #35Parameter changes

2Speed

If conventional mixers are used, then frequency translation is achieved, but undesirable harmonics are generated

Engineering Contradiction:

Improvefrequency translationVSAvoidharmonic distortion

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent divides the mixing function into multiple parallel voltage-mode mixer paths, each processing signals with different phase relationships. By segmenting the signal paths and combining their outputs through voltage summation, the circuit achieves frequency translation while canceling harmonic components through destructive interference

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent converts the harmful harmonic signals into beneficial cancellation mechanisms by using phase-shifted local oscillator signals. The harmonics generated by each mixer path are made to interfere destructively with each other, transforming the harmful distortion products into a means for achieving harmonic rejection

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Area of stationary object

If voltage mode operation is implemented, then area efficiency is improved, but conventional HRM designs cannot operate effectively in voltage mode

Engineering Contradiction:

Improvedie areaVSAvoidoperational effectiveness

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent successfully implements voltage-mode operation by replacing current-mode electromagnetic components with voltage-mode transistor circuits. The design uses voltage-controlled switches and capacitive coupling to achieve effective voltage-mode mixing while maintaining operational reliability through careful biasing and signal conditioning

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10305522B1Communication circuit including voltage mode harmonic-rejection mixer (HRM)

Publication Date: 2019.05.28 QUALCOMM INC

AI summary

A communication circuit may include mixers configured to generate voltage mode outputs. The communication circuit may further include voltage nodes configured to sum the voltage mode outputs produced by the mixers to generate intermediate voltage mode signals. The communication circuit may further include transconductors configured to convert the intermediate voltage mode signals to intermediate current mode signals. The communication circuit may further include at least one current node configured to sum the intermediate current mode signals to generate at least one mixer output signal.