Split-Mixer Current Conveyor for Blocking-Tolerant RF Gain
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Solution Overview
Problem
Current current conveyer technologies in RF transceivers face challenges in processing desired signals and blocking signals simultaneously without significant reduction in gain, especially when the blocking signal has a larger amplitude, and they often require high power dissipation and occupy significant die area.
Innovation Solution
The proposed solution involves a split-mixer current conveyor circuit with two frequency mixers and a current conveyer, operating in a push-pull mode, which uses a pair of PMOS and NMOS transistors with cascode transistors to maintain low input impedance and high output impedance, allowing efficient processing of both desired and blocking signals without significant gain reduction, while minimizing power dissipation and die area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional current conveyer technologies are used to process both desired and blocking signals, then signal processing capability is maintained, but power dissipation increases and die area expands
Solution Approach 1:
The current conveyer is divided into two separate stages: a first stage that processes the desired signal and a second stage that processes the blocking signal. This segmentation allows each stage to be optimized for its specific function, reducing overall power dissipation while maintaining signal processing capability. The first stage uses a first common gate/base differential amplifier and the second stage uses a second common gate/base differential amplifier, enabling independent optimization of each processing path.
2Reliability
If conventional current conveyer technologies are used to handle large amplitude blocking signals, then blocking signal processing is achieved, but gain of desired signal is significantly reduced
Solution Approach 1:
The signal processing path is segmented into two independent stages. The first stage processes the desired signal with high gain while the second stage handles the blocking signal separately. This prevents the blocking signal from loading down the first stage and reducing the desired signal gain. The output of the second stage is combined with the first stage output to produce the final output signal.
Solution Approach 2:
The second common gate/base differential amplifier acts as an intermediary that handles the blocking signal before it can interfere with the desired signal processing. By introducing this intermediate processing stage, the blocking signal is managed separately, allowing the first stage to maintain high gain for the desired signal while the second stage adapts to handle the blocking signal's large amplitude.
3Ease of manufacture
If conventional current conveyer topologies are used, then basic current transfer function is achieved, but die area occupied is significant
Solution Approach 1:
The patent merges the functionality of multiple amplifiers into a unified two-stage current conveyer structure. The first and second common gate/base differential amplifiers are combined in a push-pull configuration, allowing shared circuit elements and reduced overall die area while maintaining the current transfer function. This merging reduces the total component count and interconnect area compared to separate conventional implementations.
Data Source
AI summary
The disclosure relates to technology for an apparatus having a current conveyer comprising a first stage having a first differential input, and a second stage having a second differential input. The first and second stages are configured to operate in a push-pull mode to provide an output signal at a current conveyer output between the first stage and the second stage. The apparatus has a first frequency mixer configured to generate a first mixer signal based on an input signal and an oscillator signal having a first frequency. The first frequency mixer is configured to provide the first mixer signal to the first differential input. The apparatus has a second frequency mixer configured to generate a second mixer signal based on the input signal and a second oscillator signal having the first frequency. The second frequency mixer is configured to provide the second mixer signal to the second differential input.