Single-Ended Differential Amplifier Topology for Broadband RF Receivers
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Solution Overview
Problem
Existing low noise amplifiers in radio frequency receivers have a large area and limited frequency range due to the use of inductors and capacitors, which restricts broadband coverage and increases the number of amplifiers required.
Innovation Solution
A single-ended-to-differential amplifier design utilizing three inverting amplifiers and an impedance element, implemented using MOS technology, which eliminates the need for inductors and allows for a smaller area and broader frequency range, enabling broadband matching with fewer amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a passive inductor Balun is used to implement single-ended input and differential output, then the low noise amplifier can achieve the desired signal conversion, but the area of the amplifier increases significantly
Solution Approach 1:
The patent extracts and removes the inductor component from the traditional passive inductor Balun structure. By using an active circuit implementation with operational amplifiers and impedance elements, the solution eliminates the need for large-area inductors while maintaining the single-ended to differential conversion function, thereby significantly reducing the amplifier area.
Solution Approach 2:
The patent replaces the passive electromagnetic inductor-based Balun structure with an active electronic circuit implementation using operational amplifiers and impedance elements. This substitution transitions from a component-based passive system to an active electronic system, achieving the same signal conversion function with reduced area.
2Power
If inductors and capacitors are used as loads in the low noise amplifier, then the amplifier can provide signal amplification, but the frequency range becomes limited
Solution Approach 1:
The patent employs operational amplifiers with adjustable impedance elements that can dynamically adapt to different frequency conditions. Unlike fixed-value inductors and capacitors, the active circuit implementation allows for dynamic compensation and adjustment, enabling the amplifier to maintain stable performance across a broader frequency range.
Solution Approach 2:
The patent changes the fundamental parameters of the amplifier by replacing passive LC loads with active operational amplifier-based impedance simulation. This parameter change allows the circuit to operate without the resonant frequency constraints of traditional LC tanks, thereby expanding the usable frequency range while maintaining amplification capability.
3Adaptability or versatility
If multiple low noise amplifiers are used to implement broadband coverage, then the frequency range increases, but the area of the radio frequency receiver increases further
Solution Approach 1:
The patent creates a universal amplifier design that can handle multiple frequency bands using a single amplifier circuit. By implementing single-ended to differential conversion with active circuits, the amplifier becomes frequency-agnostic and can serve multiple bands without requiring separate dedicated amplifiers for each band, thereby reducing the total number of amplifiers needed.
Solution Approach 2:
The patent merges the functions of multiple band-specific amplifiers into a single broadband-capable amplifier. By combining the single-ended to differential conversion function with active impedance simulation, the solution consolidates what would traditionally require multiple separate amplifier circuits into one unified structure, reducing overall receiver area.
Data Source
AI summary
The present disclosure relates to single-ended-to-differential amplifiers and radio frequency receivers. One example single-ended-to-differential amplifier includes a first inverting amplifier, a second inverting amplifier, and a third inverting amplifier. Both an input end of the first inverting amplifier and an input end of the second inverting amplifier are coupled to an input end of the single-ended-to-differential amplifier, an output end of the first inverting amplifier is coupled to an input end of the third inverting amplifier, an output end of the second inverting amplifier is coupled to a first output end of the single-ended-to-differential amplifier, and an output end of the third inverting amplifier is coupled to a second output end of the single-ended-to-differential amplifier. An impedance element is coupled between the input end of the first inverting amplifier and the output end of the first inverting amplifier.