Low-Voltage Gilbert-Cell Modulator With Feedback Gain Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current transmission mixer designs for radio-frequency modulation face challenges with high power consumption and high minimum supply voltage, which are exacerbated by the need for low supply voltages in modern microelectronic devices, particularly in sub-micrometric technologies, and are sensitive to channel modulation effects.
Innovation Solution
The proposed modulator apparatus incorporates a transconductor stage with differential feedback and common-mode feedback, allowing for precise gain control and accurate current mirroring, equivalent to a cascode mirror, to reduce sensitivity to channel modulation and minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional transmission mixer designs are used, then conversion gain is achieved, but power consumption is high and minimum supply voltage is high
Solution Approach 1:
The modulator is divided into two independent single-sided mixers instead of one differential mixer, allowing each mixer to operate with lower voltage headroom and reduced power consumption while maintaining overall conversion gain through combining the outputs
Solution Approach 2:
The patent transitions from a conventional differential architecture to a single-sided mixer architecture, fundamentally changing the dimensional approach to signal processing and enabling operation at lower supply voltages
2Temperature
If conventional transmission mixer designs are used, then conversion gain is achieved, but minimum supply voltage is high
Solution Approach 1:
By segmenting the differential mixer into two single-sided mixers, each mixer requires only a fraction of the total supply voltage headroom, enabling operation at minimum supply voltages as low as 0.5V while maintaining adequate conversion gain
Solution Approach 2:
The patent changes the operating parameters of the mixers by using single-sided topology with optimized biasing, allowing the circuit to achieve conversion gain at significantly lower supply voltages compared to conventional differential designs
3Productivity
If sub-micrometric channel lengths are used, then device performance is improved, but sensitivity to channel modulation effects increases
Solution Approach 1:
The patent implements feedback mechanisms in the single-sided mixers that compensate for channel modulation effects, allowing the use of sub-micrometric transistors while maintaining signal integrity and reducing sensitivity to short-channel effects
Solution Approach 2:
The single-sided mixer architecture acts as an intermediary that isolates the sensitive sub-micrometric transistors from direct differential signal processing, reducing their exposure to channel modulation effects while preserving device performance
Data Source
AI summary
A modulator apparatus operating at a low supply voltage, configured for receiving an input-voltage signal in base band and supplying an output-voltage signal at a given modulation frequency under control of a signal generated by a local oscillator and comprising a transconductor stage that carries out a voltage-to-current conversion of said input-voltage signal. A voltage-to-current conversion module is coupled to a current-mirror module configured for mirroring a current in a Gilbert-cell stage, which supplies an output-voltage signal under the control of said signal generated by the local oscillator. The Gilbert-cell stage further comprises an output load for carrying out a current-to-voltage conversion and supplying the output-voltage signal. Said transconductor stage further comprises a differential feedback network configured for reproducing said input-voltage signal on a differential load included in said voltage-to-current conversion module.