Variable-Gain Down-Conversion Mixer for Low-Noise Power Saving
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Solution Overview
Problem
Conventional down-conversion mixers have fixed conversion gain and high noise figure, leading to high power consumption due to large power supply voltages, which limits their efficiency and increases power consumption.
Innovation Solution
A down-conversion mixer with a variable conversion gain is achieved by incorporating a converting-and-mixing circuit and a load circuit with transistors and resistors whose transconductance varies with control voltage, allowing adjustment of the conversion gain and noise figure through control voltage and resistor settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If parameters of all elements are fixed in conventional down-conversion mixer, then the structure is simple, but the conversion gain is fixed and cannot be adjusted
Solution Approach 1:
The patent applies dynamics by making the conversion gain adjustable through control voltages applied to the transistors in the converting-and-mixing circuit and load circuit. The transconductance of these transistors varies according to the control voltages, enabling dynamic adjustment of conversion gain without changing the basic circuit structure.
Solution Approach 2:
The patent changes the electrical parameters (transconductance) of the transistors by applying different control voltages. This allows the conversion gain and noise figure to be adjusted by varying the control voltages and resistor settings, achieving parameter adaptability while maintaining the same circuit topology.
2Reliability
If conversion gain is low and noise figure is high in conventional mixer, then power supply voltages must be large, but this results in high power consumption
Solution Approach 1:
The patent changes the transconductance parameters of the transistors through control voltages, enabling the conversion gain to be adjusted to appropriate levels. This allows the mixer to achieve good signal quality with lower power supply voltages, thereby reducing power consumption while maintaining reliability.
3Power
If power supply voltages are large in conventional mixer, then power consumption is high, but this is necessary to achieve adequate conversion gain
Solution Approach 1:
The patent uses dynamic control voltages to adjust the transconductance of transistors, enabling the conversion gain to be optimized without increasing power supply voltages. This decouples the relationship between power consumption and conversion gain, allowing high conversion gain to be achieved with low power consumption.
Data Source
AI summary
A down-conversion mixer includes a converting-and-mixing circuit and a load circuit. The converting-and-mixing circuit performs voltage to current conversion and mixing with a differential oscillatory voltage signal pair upon a differential input voltage signal pair to generate a differential mixed current signal pair. The load circuit includes two transistors each having a transconductance that varies according to a control voltage, two resistors each decreasing a threshold voltage of a respective one of the transistors, and a resistor-inductor circuit cooperating with the transistors to convert the differential mixed current signal pair into a differential mixed voltage signal pair.